High-elasticity and high-toughness 3D printing photosensitive resin and preparation method thereof
By preparing functionalized PUA oligomers containing polyurea bonds and amide hydrogen bonds, and combining them with optimized formulations, the problems of high brittleness and insufficient toughness of photosensitive resins have been solved, resulting in a photosensitive resin with high elasticity and high toughness. This resin is suitable for 3D printing of flexible functional parts and impact-resistant structural parts, is compatible with mainstream photopolymerization 3D printing equipment, and is suitable for large-scale production.
Patent Information
- Application Number
- CN202610630862.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-09
- Publication Date
- 2026-07-10
AI Technical Summary
Existing 3D printing photosensitive resins are brittle and lack elasticity and toughness after curing. Modification processes are complex and it is difficult to balance printing performance and mechanical properties, which limits their application in flexible functional parts and impact-resistant structural parts.
Functionalized PUA oligomers containing polyurea bonds and amide hydrogen bonds were prepared by synthetic addition polymerization and grafting reactions. In combination with reactive diluents, photoinitiators, toughening agents, interface modifiers and antioxidants, the formulation composition and preparation process were optimized to form a dynamic cross-linked network, achieving high elasticity and high toughness.
It achieves high elasticity and high toughness of photosensitive resin, with finished products having an elongation at break of 200-300%, a Shore A hardness of 60-65, an impact strength of ≥200kJ/m², and an elastic recovery rate of ≥95%. It is compatible with mainstream photopolymerization 3D printing equipment, and the printed products have a smooth surface and high dimensional accuracy, making them suitable for mass production.
Smart Images
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Abstract
Description
Technical Background
[0001] Photopolymer 3D printing technology, with its advantages of high forming accuracy and fast forming speed, is widely used in precision manufacturing, medical consumables, automotive parts, flexible materials, and other fields. Its performance directly determines the quality and application scenarios of printed products. To improve the toughness and elasticity of photosensitive resins, existing technologies mostly adopt physical toughening or formulation modification methods. Physical toughening is often achieved by adding reinforcing phases such as nanomaterial particles and bio-based fillers, but it is prone to problems such as poor compatibility and poor dispersion between the toughening elastomer and the resin matrix, resulting in decreased printing accuracy and deterioration of surface quality. Formulation modification involves adding flexible prepolymers, but it often presents a contradiction between elasticity and toughness, and between curing speed and mechanical properties. Moreover, some modification processes are complex and costly, which is not conducive to large-scale production. Furthermore, such resins generally have high brittleness, insufficient toughness, and poor elastic recovery performance after curing. Printed products are prone to breakage under external impact and are difficult to restore their original shape after deformation, limiting their application in high-end scenarios such as flexible functional parts and impact-resistant structural parts. Therefore, developing a method for preparing 3D printing photosensitive resin that has a reasonable formula, simple process, excellent elasticity and toughness, and does not sacrifice printing performance has become a technical problem that the industry urgently needs to solve. Summary of the Invention
[0002] This invention aims to overcome the shortcomings of existing 3D printing photosensitive resins, such as high brittleness, insufficient elasticity and toughness after curing, complex modification processes, and difficulty in simultaneously achieving printing performance and mechanical properties. It provides a method for preparing a high-elasticity, high-toughness 3D printing photosensitive resin. Through synthetic addition polymerization and grafting reactions, coupled with optimized formulation and preparation processes, the photosensitive resin possesses excellent elastic recovery properties, fracture toughness, and photocuring performance, making it compatible with mainstream photocuring 3D printing technologies such as LCD, SLA, and DLP, and meeting the application requirements of flexible functional parts and impact-resistant structural parts.
[0003] The preparation method of the present invention includes the following steps: 1. Synthesis of hydrogen-bonded functionalized PUA oligomers: Polycaprolactone neopentyl diol (PCL) (molecular weight 2000 g / mol) was placed in a reactor at 110℃ and evacuated for 2.5 h using a circulating water vacuum pump, maintaining the vacuum at 0.05 MPa to remove moisture and avoid side reactions. After cooling to 45-55℃, the mixture was transferred to a nitrogen-protected four-necked flask, and isophorone diisocyanate (IPDI) and dibutyltin dilaurate (DBTDL) catalysts were added. The molar ratio of IPDI to PCL was (1:1), and the amount of DBTDL added was 0.05-0.1% of the PCL mass. The mixture was heated to 65-75℃ and stirred for 1.5 h. -2.5h, forming an NCO prepolymer; then cooling to 40-50℃, slowly adding hydrogen-bonded and amino-bonded acrylate monomer—tert-butylaminoethyl methacrylate (TBAEMA), with a molar ratio of TBAEMA to the remaining NCO groups of 1:1. After the addition is complete, the reaction is kept at a constant temperature for 1-2h. The disappearance of the NCO characteristic peak (2270cm⁻¹) is monitored by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), yielding a functionalized PUA oligomer with polyurea bonds and amide hydrogen bonds, which is then cooled to room temperature for later use.
[0004] 2. Preparation of the mixed system: The synthesized PUA prepolymer was added to a high-speed disperser. Under the conditions of 800-1200 r / min and 35-45℃, reactive diluent, photoinitiator, toughening agent, interface modifier and antioxidant were added in sequence and dispersed for 30-45 minutes. The viscosity was adjusted by using reactive diluent and controlled at 500-600 mPa.s (25℃) to obtain a uniform mixture. The obtained mixture was filtered through a 200-300 mesh filter membrane to obtain a high-elasticity and high-toughness 3D printing photosensitive resin.
[0006] Functionalized PUA oligomers, accounting for 38-50%; the above-mentioned functionalized PUA oligomers with polyurea bonds and amide hydrogen bonds are synthesized by molecular design to form a dynamic cross-linking network of polyurea bonds (-NH-CO-NH-) and amide bonds (-CO-NH-) using intermolecular and intramolecular amide hydrogen bonds, so as to achieve comprehensive properties such as high elasticity and high toughness; the rigid support of polyurea bonds and the dynamic cross-linking of amide hydrogen bonds, together with the curable properties of PUA backbone, achieve a balance of elasticity, toughness, strength and processability; Reactive diluent A, accounting for 37-52%; the reactive diluent is a mixture of hydroxypropyl methacrylate, trihydroxy(2-hydroxyethyl) isocyanurate, lauryl acrylate, polyethylene glycol (200) diacrylate, and 4-acryloylmorpholine in a mass ratio of 3:1:1:2:2; it can reduce the viscosity of the system and participate in the cross-linking reaction, thereby improving the elasticity and strength of the cured resin; Photoinitiator B, accounting for 3-5%; the photoinitiator is a compound system composed of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and 1-hydroxycyclohexylphenyl ketone (184) in a mass ratio of 4:1; it is suitable for ultraviolet / visible light in the 385-420nm band, has high curing efficiency, and can reduce curing shrinkage; Toughening agent, accounting for 5-10%; the toughening agent is an organosilicon-modified polyether elastomer with a molecular weight of 8000; it can form a flexible network in the resin matrix, significantly improving fracture toughness and elastic recovery performance. An interface modifier, comprising 0.3-1% of the total content, is γ-methacryloyloxypropyltrimethoxysilane. This interface modifier can improve the compatibility between the components and avoid performance fluctuations and printing defects caused by uneven dispersion. Antioxidant, accounting for 0.2-0.8%; the antioxidant is a mixture of hindered phenolic antioxidant (1076) and benzotriazole (UV-326) in a mass ratio of 1:1; it can improve the storage stability of the resin and the aging resistance of the cured product.
[0007] Compared with the prior art, the present invention has the following advantages: 1. Excellent Mechanical Properties: Through addition polymerization, functionalized PUA oligomers with polyurea and amide hydrogen bonds are obtained. Combined with organosilicon-modified polyether elastomer toughening agents, the cured resin exhibits both high elasticity and high toughness. The finished product has an elongation at break of 200-300%, a Shore A hardness of 60-65, an impact strength ≥200kJ / m², and an elastic recovery rate ≥95%, which is far superior to existing conventional photosensitive resins. Furthermore, it maintains stable mechanical properties within a temperature range of -20℃ to 40℃.
[0008] 2. Excellent printing performance: The optimized ratio of prepolymer to reactive diluent results in a system viscosity of 500-600cps (25℃), making it compatible with mainstream photopolymer 3D printing equipment such as LCD, SLA, and DLP. The curing depth is 0.10-0.20mm in the 385-420nm wavelength range. It features fast curing speed, smooth printed surfaces, high dimensional accuracy, and no significant shrinkage or deformation.
[0009] 3. Simple and controllable process: The preparation process does not require high temperature and high pressure conditions, the reaction conditions are mild, the components have good compatibility and are evenly dispersed, no complicated post-processing is required, it is suitable for large-scale mass production, and the production cost is lower than that of similar high-performance elastic photosensitive resins.
[0010] 4. Wide range of applications: The product has excellent elasticity, toughness and molding precision, and can be widely used in flexible electronic shells, medical rehabilitation equipment, automotive cushioning parts, impact-resistant models and other scenarios, expanding the application boundaries of photopolymer 3D printing technology. Detailed Implementation
[0011] The preparation method of the present invention includes the following steps: 1. Synthesis of hydrogen-bonded functionalized PUA oligomers 300g of polycaprolactone neopentyl glycol (PCL) (molecular weight 2000 g / mol) was placed in a reactor at 110℃. A vacuum pump was used to evacuate the reactor for 2.5 hours, maintaining the vacuum at 0.05MPa, to remove moisture and avoid side reactions. After cooling to 45-55℃, nitrogen gas was introduced into the reactor for protection to prevent oxygen inhibition and yellowing. 33.4g of IPDI (IPDI to PCL molar ratio 1:1) and 0.15g of DBTDL were added. The mixture was heated to 75℃ and stirred for 2.5 hours. The NCO value was detected by ATR-FTIR. When half of the NCO peak disappeared, an NCO-terminated prepolymer was formed. Subsequently, the temperature was lowered to 40-50℃ by cooling water, and 13.8g of tert-butylaminoethyl methacrylate (1:1 molar ratio with the remaining NCO) was slowly added dropwise. After reacting for 2 hours, the NCO characteristic peak disappeared by ATR-FTIR. The mixture was cooled to room temperature to obtain a functionalized PUA oligomer with polyurea and amide hydrogen bonds.
[0012] 2.3D Printing Photosensitive Resin Application Formulation Case: 3D printed photosensitive resin sample 1
[0013] 3D printed photosensitive resin sample 2
[0014] 3D printed photosensitive resin sample 3
[0015] 3D printed photosensitive resin sample 4
[0016] 3D printed photosensitive resin sample 5
[0017] The above formulation and operation process: Under the conditions of rotation speed of 800-1200 r / min and temperature of 35-45℃, add reactive diluent, photoinitiator, toughening agent, interface modifier and antioxidant in sequence, disperse for 30-45 minutes, adjust the viscosity with reactive diluent, and control the viscosity at 500-600 mPa.s (25℃), and filter the resulting mixture through a 200-300 mesh filter membrane to obtain a high elasticity and high toughness 3D printing photosensitive resin.
[0018] The test results show that both toughness and elasticity are acceptable, with sample 3 being the best (see below). Sample 3 contained 45g of functionalized PUA oligomer with polyurea bonds and amide hydrogen bonds; 40g of reactive diluent A; 4g of photoinitiator B; 10g of toughening agent; 0.7g of interface modifier; and 0.3g of antioxidant. The photosensitive resin prepared by dispersing at 800-1200 r / min for 30 minutes was the optimal one.
[0019] The finished product exhibits an elongation at break of 200-300%, a Shore A hardness of 60-65, an impact strength ≥200kJ / m², and an elastic recovery rate ≥95%, far superior to existing conventional photosensitive resins. It also maintains stable mechanical properties within a temperature range of -20℃ to 40℃. It demonstrates excellent printing performance; the optimized ratio of prepolymer to reactive diluent results in a viscosity of 500-600cps (25℃), making it compatible with mainstream photopolymer 3D printing equipment such as SLA and DLP. The curing depth is 0.10-0.20mm in the 385-420nm wavelength range, with fast curing speed, smooth surface finish, high dimensional accuracy, and no significant shrinkage or deformation in the printed products.
Claims
1. A high-elasticity, high-toughness 3D printing photosensitive resin, characterized in that... According to the weight ratio, it includes: Functionalized PUA oligomers 38-50%; Reactive diluent A 37-52%; Photoinitiator B 3-5%; Toughening agent 5-10%; Antioxidant 0.2-0.8%; The active diluent is a mixture of hydroxypropyl methacrylate, trihydroxy(2-hydroxyethyl) isocyanurate, lauryl acrylate, polyethylene glycol (200) diacrylate, and 4-acryloylmorpholine in a mass ratio of 3:1:1:2:
2.
2. The high-elasticity, high-toughness 3D printing photosensitive resin according to claim 1, characterized in that: The photoinitiator is a compound system consisting of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and 1-hydroxycyclohexylphenyl ketone (184) in a mass ratio of 4:
1.
3. The high-elasticity, high-toughness 3D printing photosensitive resin according to claim 2, characterized in that: The toughening agent is an organosilicon-modified polyether elastomer with a molecular weight of 8000; The interface modifier is γ-methacryloyloxypropyltrimethoxysilane.
4. The high-elasticity, high-toughness 3D printing photosensitive resin according to claim 1, characterized in that: The antioxidant is a mixture of hindered phenolic antioxidant (1076) and benzotriazole (UV-326) in a mass ratio of 1:
1.
5. The method for preparing a high-elasticity, high-toughness 3D printing photosensitive resin according to claim 1, characterized in that... Includes the following steps:
1. Synthesis of hydrogen-bonded functionalized PUA oligomers: Polycaprolactone neopentyl diol (PCL) (molecular weight 2000 g / mol) was placed in a reactor at 110℃ and evacuated for 2.5 h using a circulating water vacuum pump, maintaining the vacuum at 0.05 MPa to remove moisture and avoid side reactions. After cooling to 45-55℃, the mixture was transferred to a nitrogen-protected four-necked flask, and isophorone diisocyanate (IPDI) and dibutyltin dilaurate (DBTDL) catalysts were added. The molar ratio of IPDI to PCL was (1:1), and the amount of DBTDL added was 0.05-0.1% of the PCL mass. The mixture was heated to 65-75℃ and stirred for 1.5 h. -2.5h, forming NCO prepolymer; then cool to 40-50℃, slowly add hydrogen-bonded and amino-bonded acrylate monomer - tert-butylaminoethyl methacrylate (TBAEMA), with a molar ratio of TBAEMA to the remaining NCO groups of 1:
1. After the addition is completed, react at a constant temperature for 1-2h. Monitor the disappearance of the NCO characteristic peak (2270cm⁻¹) by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to obtain functionalized PUA oligomers with polyurea bonds and amide hydrogen bonds, and cool to room temperature for later use; 2. Preparation of the mixed system: The synthesized PUA prepolymer was added to a high-speed disperser. Under the conditions of 800-1200 r / min and 35-45℃, reactive diluent, photoinitiator, toughening agent, interface modifier and antioxidant were added in sequence and dispersed for 30-45 minutes. The viscosity was adjusted by using reactive diluent and controlled at 500-600 mPa.s (25℃) to obtain a uniform mixture. The obtained mixture was filtered through a 200-300 mesh filter membrane to obtain a high-elasticity and high-toughness 3D printing photosensitive resin.