Photocurable resin, preparation method and use

Abstract

The present application relates to the technical field of photocuring 3D printing and discloses a photocurable resin, a preparation method and a use. The photocurable resin provided in the present application comprises an acrylate oligomer, a reactive diluent, a multifunctional thiol, a polymerization inhibitor, a benzoxazole absorber, an ultraviolet absorber, a photoinitiator, a dye, and a light stabilizer, wherein the acrylate oligomer and the reactive diluent are main components of the photocurable resin. The addition of both the multifunctional thiol and the polymerization inhibitor can inhibit the reaction speed at low energy while improving the curing rate, and reduce the curing thickness while improving the curing degree, thereby improving the printing precision. In addition, the addition of the benzoxazole absorber and the ultraviolet absorber can also reduce the curing thickness, and these components play a synergistic role, thereby improving the printing precision.

Description

UV-curable resins, preparation methods and applications

[0001] This disclosure is based on and claims priority to Chinese Patent Application No. 202411508828.8, filed on October 25, 2024, entitled "Photocurable Resin, Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photocurable 3D printing technology, and in particular to a photocurable resin, its preparation method, and its application. Background Technology

[0003] Photopolymer 3D printing is a method of producing 3D products by curing a photopolymer resin layer by layer using ultraviolet light. For transparent 3D printing materials, light easily penetrates deep into the resin, often causing areas without a defined pattern to be exposed to UV light and cure, resulting in overexposure and a significant decrease in product precision. The precision of photopolymer 3D printing is limited by the layer thickness of each layer. For high-precision applications, such as dental and precision parts, lower layer thicknesses are often required to achieve higher accuracy. Lower layer thicknesses necessitate that the photopolymer resin, at a set curing energy, has both a lower cured layer thickness and a higher degree of cure. Therefore, it is necessary to provide a photopolymer resin with low cured layer thickness and high degree of cure to improve printing precision. Summary of the Invention

[0004] This application provides a photocurable resin, its preparation method, and its application. The photocurable resin exhibits both a low cured layer thickness and a high degree of cure, making it suitable for photocuring transparent materials in 3D printing. The technical solution is as follows:

[0005] On one hand, a photocurable resin is provided, the photocurable resin comprising the following components in parts by weight:

[0006] The composition includes: 40-70 parts acrylate oligomer, 20-50 parts reactive diluent, 5-20 parts polyfunctional thiols, 0.5-1.5 parts polymerization inhibitor, 1-5 parts photoinitiator, 0-0.5 parts ultraviolet absorber, 0.1-2 parts benzoxazole absorber, 0.001-0.01 parts dye, and 0.1-0.5 parts light stabilizer.

[0007] In one possible implementation, the acrylate oligomer is selected from at least one of aliphatic polyurethane acrylates and epoxy acrylates.

[0008] In another possible implementation, the acrylate oligomer is selected from at least one of Sartoma CN989, CN1964NS, Changxing Chemical EM3261, Runao Chemical FSP8091, Bomar BR-952, and Rahn Chemical Genomer*4337.

[0009] In another possible implementation, the reactive diluent is selected from at least one of monofunctional acrylates or methacrylates, difunctional acrylates or methacrylates, and acrylamide monomers.

[0010] In another possible implementation, the polyfunctional thiol is selected from at least one of trimethylolpropane tris(3-mercaptopropionic acid), tris[2-(3-mercaptopropoxy)ethyl]isocyanurate, pentaerythritol tetra(3-mercaptopropionic acid), pentaerythritol tetra(3-mercaptobutyric acid), and dipentaerythritol hexa(3-mercaptopropionic acid).

[0011] In another possible implementation, the benzoxazole absorbent is selected from at least one of 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, 2,2-(4,4-stilbeneyl)bisbenzoxazole, 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 1,4-bis(benzoxazol-2-yl)naphthalene, and Lotte Chemical FV-100.

[0012] In another possible implementation, the photoinitiator is selected from at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone.

[0013] In another possible implementation, the ultraviolet absorber is selected from at least one of UV3035, UV1130, and UV400.

[0014] On the other hand, a method for preparing a photocurable resin is provided, the method comprising:

[0015] Add reactive diluent and dye to the container according to the mass fractions of each component, and ultrasonically disperse for 20 min to 60 min;

[0016] Continue to add photoinitiator, multifunctional thiol, ultraviolet absorber, benzoxazole absorber, light stabilizer and polymerization inhibitor, and disperse at a speed of 600 r / min to 800 r / min for 40 min to 80 min;

[0017] Continue adding acrylate oligomers and disperse at a speed of 800 r / min to 1200 r / min for 40 min to 80 min. After filtration and standing to defoam, the photocurable resin is obtained.

[0018] On the other hand, an application of photocurable resin in photocurable 3D printing transparent materials is provided.

[0019] This application provides a photocurable resin comprising acrylate oligomers, reactive diluents, polyfunctional thiols, polymerization inhibitors, benzoxazole absorbers, ultraviolet absorbers, photoinitiators, dyes, and light stabilizers. The acrylate oligomers and reactive diluents form the main components of the photocurable resin. The addition of polyfunctional thiols and polymerization inhibitors simultaneously increases the curing rate while suppressing reaction rates at low energy levels. This improves the degree of curing while reducing the cured thickness, thus enhancing printing accuracy. Furthermore, the addition of benzoxazole absorbers and ultraviolet absorbers also reduces the cured thickness, demonstrating the synergistic effect of the components and improving printing accuracy.

[0020] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this disclosure. Attached Figure Description

[0021] Figure 1 is a schematic diagram of a 3D transparent dental brace provided in an embodiment of this application. Detailed Implementation

[0022] To make the technical solution and advantages of this application clearer, the embodiments of this application will be described in further detail below.

[0023] On one hand, embodiments of this application provide a photocurable resin, which comprises the following components in parts by weight:

[0024] The composition includes: 40-70 parts acrylate oligomer, 20-50 parts reactive diluent, 5-20 parts polyfunctional thiols, 0.5-1.5 parts polymerization inhibitor, 1-5 parts photoinitiator, 0-0.5 parts ultraviolet absorber, 0.1-2 parts benzoxazole absorber, 0.001-0.01 parts dye, and 0.1-0.5 parts light stabilizer.

[0025] The mass fractions of the acrylate oligomers can be 40, 42, 45, 50, 52, 55, 60, 62, 65, or 70 parts; the mass fractions of the reactive diluents can be 20, 22, 25, 30, 32, 35, 40, 45, 48, or 50 parts; the mass fractions of the polyfunctional thiols can be 5, 8, 9, 10, 12, 15, 18, or 20 parts; the mass fractions of the polymerization inhibitors can be 0.5, 0.6, 0.7, 0.8, 1, 1.2, 1.4, or 1.5 parts; the mass fractions of the photoinitiator can be 1, 2, 2.5, 3, 3.5, 4, 4.5, or 5 parts; and the mass fractions of the ultraviolet absorbers can be... The mass fractions can be 0 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, etc.; the mass fractions of benzoxazole absorbents can be 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, etc.; the mass fractions of dyes can be 0.001 parts, 0.002 parts, 0.003 parts, 0.004 parts, 0.005 parts, 0.006 parts, 0.007 parts, 0.008 parts, 0.009 parts, 0.01 parts, etc.; and the mass fractions of light stabilizers can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, etc.

[0026] This application provides a photocurable resin comprising acrylate oligomers, reactive diluents, polyfunctional thiols, polymerization inhibitors, benzoxazole absorbers, ultraviolet absorbers, photoinitiators, dyes, and light stabilizers. The acrylate oligomers and reactive diluents form the main components of the photocurable resin. The addition of polyfunctional thiols and polymerization inhibitors simultaneously increases the curing rate while suppressing reaction rates at low energy levels. This improves the degree of curing while reducing the cured thickness, thus enhancing printing accuracy. Furthermore, the addition of benzoxazole absorbers and ultraviolet absorbers also reduces the cured thickness, demonstrating the synergistic effect of the components and improving printing accuracy.

[0027] In one possible implementation, the acrylate oligomer is selected from at least one of aliphatic polyurethane acrylates and epoxy acrylates.

[0028] In this implementation, the acrylate oligomer can be an aliphatic polyurethane acrylate, an epoxy acrylate, or a blend of aliphatic polyurethane acrylate and epoxy acrylate. If the acrylate oligomer is a blend of aliphatic polyurethane acrylate and epoxy acrylate, the blending ratio between the two can be set and changed as needed. For example, the mass ratio of aliphatic polyurethane acrylate to epoxy acrylate can be 20:40, 20:35, 30:30, 20:25, 20:30, 40:25, 40:20, etc., without specific limitations.

[0029] Among them, the functionality of aliphatic polyurethane acrylate and epoxy acrylate is 2 to 3, and the weight-average molecular weight ranges from 400 g / mol to 2000 g / mol.

[0030] The acrylate oligomer can be specifically selected from at least one of Sartoma CN989, CN1964NS, Changxing Chemical EM3261, Runao Chemical FSP8091, Bomar BR-952, and Rahn Chemical Genomer*4337.

[0031] Among them, Sartoma CN989, CN1964NS, FSP8091, Bomar BR-952, and Rahn Chemical Genomer*4337 belong to aliphatic polyurethane acrylates, while Changxing Chemical EM3261 belongs to epoxy acrylates.

[0032] The weight-average molecular weights of aliphatic polyurethane acrylates can be 400 g / mol, 500 g / mol, 600 g / mol, 700 g / mol, 800 g / mol, 900 g / mol, 1000 g / mol, 1100 g / mol, 1200 g / mol, 1300 g / mol, 1400 g / mol, 1500 g / mol, 1600 g / mol, 1700 g / mol, 1800 g / mol, 1900 g / mol, and 2000 g / mol. The weight-average molecular weight of epoxy acrylates can be 400 g / mol, 500 g / mol, 600 g / mol, 700 g / mol, 800 g / mol, 900 g / mol, 1000 g / mol, 1100 g / mol, 1200 g / mol, 1300 g / mol, 1400 g / mol, 1500 g / mol, 1600 g / mol, 1700 g / mol, 1800 g / mol, 1900 g / mol, 2000 g / mol, etc.

[0033] In the embodiments of this application, the molecular weight of the acrylate oligomer not only affects the curing speed of the photocurable resin but also its viscosity. Acrylic oligomers with higher molecular weights have higher viscosity, while those with lower molecular weights have lower viscosity. Selecting acrylate oligomers within the aforementioned molecular weight range allows the photocurable resin to achieve suitable curing speed and viscosity. Correspondingly, the functionality of the acrylate oligomer also affects the performance of the photocurable resin. The level of functionality determines the length of the polymer molecular chain and the crosslinking density, thus influencing the performance of the photocurable resin.

[0034] This application uses acrylate oligomers with the above-mentioned molecular weight range and functionality with other components, which can not only give the photocurable resin a suitable viscosity and curing speed, but also improve the performance of the photocurable resin.

[0035] In one possible implementation, the reactive diluent is selected from at least one of monofunctional acrylates or methacrylates, difunctional acrylates or methacrylates, and acrylamide monomers.

[0036] The monofunctional acrylate or methacrylate is selected from at least one of isobornyl acrylate (IBOA), 4-tert-butylcyclohexyl acrylate (TBCHA), 3,3,5-trimethylcyclohexyl acrylate (TMCHA), isobornyl methacrylate (IBOMA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), and Rahn Chemical Genomer*1122.

[0037] The difunctional acrylate or methacrylate is selected from at least one of tripropylene glycol diacrylate (TPGDA), tetraethyl bisphenol A diacrylate (BPA4EODA), decaethyl bisphenol A diacrylate (BPA10EODA), and triethylene glycol dimethacrylate (TEGDMA).

[0038] The acrylamide monomers are selected from at least one of 4-acryloylmorpholine (ACMO), dimethylacrylamide (DMAA), and diethylacrylamide (DEAA).

[0039] In the embodiments of this application, the use of the above-mentioned reactive diluent in combination with other components can reduce the viscosity of the photocurable resin and improve its flowability.

[0040] In one possible implementation, the polyfunctional thiol is selected from at least one of trimethylolpropane tris(3-mercaptopropionic acid) ester (TMPMP), tris[2-(3-mercaptopropoxy)ethyl]isocyanurate (TEMPIC), pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), pentaerythritol tetrakis(3-mercaptobutyric acid) ester (PE1), and dipentaerythritol hexa(3-mercaptopropionic acid) ester (DTMPS).

[0041] Among them, TMPMP and TEMPIC are trifunctional thiols, PETMP and PE1 are tetrafunctional thiols, and DTMPS are hexafunctional thiols.

[0042] In the embodiments of this application, a multifunctional thiol is used in combination with polymerization inhibitors and other components. This can improve the overall curing rate while inhibiting the curing effect at low energy. It can also improve the degree of curing while reducing the curing thickness. Furthermore, the addition of multifunctional thiols can also improve oxygen inhibition, increase the curing speed of photocurable resins, and reduce the viscosity of photocurable resins.

[0043] In one possible implementation, the benzoxazole absorbent is selected from at least one of 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene (OB), 2,2-(4,4-stilbeneyl)bisbenzoxazole, 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 1,4-bis(benzoxazol-2-yl)naphthalene, and Lotte Chemical FV-100.

[0044] In the embodiments of this application, benzoxazole absorbers can adjust the curing layer thickness and curing precision of photocurable resins, and while absorbing light energy, they can synergistically generate energy conversion with photoinitiators to improve the curing degree of photocurable resins.

[0045] In one possible implementation, the photoinitiator is selected from at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator TPO), 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (photoinitiator TMO), 1-hydroxycyclohexylphenyl ketone (photoinitiator 184), 2-isopropylthioxanthone (photoinitiator ITX), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (photoinitiator 369), 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (photoinitiator 379), and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone (photoinitiator 907).

[0046] Furthermore, one of TPO and TMO can be combined with one of photoinitiator 184, photoinitiator ITX, photoinitiator 369, photoinitiator 379, and photoinitiator 907 as a photoinitiator.

[0047] In this embodiment, the photoinitiator is an acylphosphine oxide photoinitiator. This type of photoinitiator has good absorption at the wavelength of the 365nm-405nm light source used in photopolymerization 3D printing, and can initiate reactive polymerization. It also has a photobleaching effect, reducing absorbance after curing and resulting in better light uniformity.

[0048] In one possible implementation, the ultraviolet absorber is selected from at least one of UV3035, UV1130, and UV400.

[0049] In the embodiments of this application, the ultraviolet absorber can adjust the curing layer thickness of the photocurable resin and improve the color stability of the photocurable resin against photoaging.

[0050] In one possible implementation, the polymerization inhibitor is selected from at least one of N-nitroso-N-phenylhydroxylamine aluminum (polymerization inhibitor 510), 2,6-di-tert-butyl-p-cresol (BHT), p-hydroxyanisole (MEHQ), phenothiazine (PTZ), Rahn Chemicals Genorad*16, and Genorad*20.

[0051] In the embodiments of this application, the polymerization inhibitor is used in combination with a multifunctional thiol. While improving the overall curing rate, it can suppress the curing effect at low energy. While improving the degree of curing, it can reduce the curing thickness. In addition, the polymerization inhibitor can also increase the stability of the system and reduce the impact of the trace amounts of transmitted and scattered light on the accuracy.

[0052] In one possible implementation, the dye is selected from blue dyes, such as at least one of elliptical crystal violet, ultramarine, and blue dyes.

[0053] In the embodiments of this application, the above-mentioned dye can not only provide the required color for the photocurable resin, but also effectively reduce the yellowing effect of the photocurable resin.

[0054] In one possible implementation, the light stabilizer is selected from at least one of Tinuvin 292, Tinuvin 770, and light stabilizer 944.

[0055] In the embodiments of this application, the above-mentioned light stabilizer can not only effectively protect the light-cured resin from ultraviolet damage and extend its service life, but also improve the color aging stability of the product.

[0056] On the other hand, embodiments of this application provide a method for preparing a photocurable resin, the method comprising:

[0057] Step 1: Add reactive diluent and dye to the container according to the mass fraction of each component, and ultrasonically disperse for 20 min to 60 min.

[0058] Add reactive diluent and dye to the tank, ultrasonically disperse for 20-60 minutes, and proceed to the next step after dissolution.

[0059] The dispersion time can be 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0060] Step 2: Continue to add photoinitiator, polyfunctional thiol, ultraviolet absorber, benzoxazole absorber, light stabilizer and polymerization inhibitor, and disperse at a speed of 600 r / min to 800 r / min for 40 min to 80 min.

[0061] One method is to use a high-speed disperser to disperse the material at a speed of 600 r / min to 800 r / min for 40 min to 80 min.

[0062] The rotation speed can be 600 r / min, 650 r / min, 680 r / min, 700 r / min, 750 r / min, 780 r / min, 800 r / min, etc. The dispersion time can be 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, etc.

[0063] Step 3: Continue to add acrylate oligomers and disperse at a speed of 800r / min to 1200r / min for 40min to 80min. After filtration and standing to defoam, the light-cured resin is obtained.

[0064] For filtration, a 300-mesh filter cloth can be used.

[0065] The rotational speed in this step can be 800 r / min, 850 r / min, 900 r / min, 950 r / min, 1000 r / min, 1050 r / min, 1100 r / min, 1150 r / min, 1200 r / min, etc. The dispersion time can be 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, etc.

[0066] On the other hand, this application also provides an application of photocurable resin in photocurable 3D printing transparent materials.

[0067] The transparent material can be used in dental applications, for precision parts, or for other applications; no specific limitations are imposed.

[0068] Printing Steps: Pour the photocurable resin into the feed tank of the photocurable 3D printer. Import the pre-printed model into the printer, set the printing parameters (such as layer thickness and single-layer illumination time), and then print. For example, the layer thickness is 30μm, and the single-layer illumination time is 3s. After printing, remove the model, remove the supports, and clean it with a solvent (such as alcohol, isopropanol, etc.). After cleaning, perform surface polishing and other treatments, and then place it in a light box for post-curing.

[0069] Referring to Figure 1, which shows a 3D transparent dental brace printed using the light-curing resin provided in this application, it can be seen that the printed 3D dental brace is transparent, has high precision, and clear details, meeting the appearance requirements of invisible orthodontic braces.

[0070] To make the technical solution and advantages of this application clearer, they will be described in detail below through specific embodiments.

[0071] In the following specific embodiments, operations without specified conditions are performed under standard conditions or conditions recommended by the manufacturer. Raw materials without specified manufacturers and specifications are all commercially available products.

[0072] Among them, the acrylate oligomers were selected from Rahn Chemical Genomer*4337, Runao Chemical FSP8091, Bomar BR-952, Sartoma CN1964NS, and Changxing Chemical EM3261;

[0073] The polyfunctional thiols are selected from PE1 and PETMP;

[0074] The reactive diluents were selected from ACMO, TBCHA, IBOA, Genomer*1122, and TMCHA;

[0075] The photoinitiator was selected from TPO, TMO, 819, 379, and 184;

[0076] The polymerization inhibitors are selected from polymerization inhibitors 510 and PTZ;

[0077] Benzoxazole absorbents were selected from OB and Lotte Chemical FV-100;

[0078] The light stabilizer was selected from Tinuvin 292;

[0079] The ultraviolet absorbers are selected from UV3035 and 1130;

[0080] The dye was selected from ultramarine.

[0081] Example 1

[0082] Example 1 provides a photocurable resin, which is prepared by the following method: 36 parts by weight of TMCHA and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; then 3 parts by weight of photoinitiator TPO, 10 parts by weight of PETMP, 0.05 parts by weight of UV3035, 0.8 parts by weight of FV-100, 0.2 parts by weight of Tinuvin 292, and 1 part by weight of PTZ are added and dispersed for 60 min; then 18 parts by weight of Genomer*4337 and 36 parts by weight of BR-952 are added and dispersed for 60 min. After filtration and standing to defoam, the photocurable resin is obtained.

[0083] Example 2

[0084] Example 2 provides a photocurable resin, which is prepared by the following method: 36 parts by weight of TMCHA and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; then 3 parts by weight of photoinitiator TMO, 10 parts by weight of PETMP, 0.05 parts by weight of UV3035, 0.8 parts by weight of FV-100, 0.2 parts by weight of Tinuvin 292, and 1 part by weight of PTZ are added and dispersed for 60 min; then 18 parts by weight of Genomer*4337 and 36 parts by weight of BR-952 are added and dispersed for 60 min. After filtration and standing to defoam, the photocurable resin is obtained.

[0085] Example 3

[0086] Example 3 provides a photocurable resin, which is prepared by the following method: 35 parts by weight of TBCHA and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 2.5 parts by weight of photoinitiator TMO, 15 parts by weight of PE1, 0.5 parts by weight of OB, 0.2 parts by weight of Tinuvin 292, and 0.8 parts by weight of PTZ are added and dispersed for 60 min; 15 parts by weight of Genomer*4337 and 35 parts by weight of FSP8091 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0087] Example 4

[0088] Example 4 provides a photocurable resin, which is prepared by the following method: 35 parts by weight of ACMO and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 2.7 parts by weight of photoinitiator TMO, 15 parts by weight of PETMP, 0.1 parts by weight of UV3035, 0.5 parts by weight of OB, 0.2 parts by weight of Tinuvin 292, and 1 part by weight of polymerization inhibitor 510 are added and dispersed for 60 min; 17 parts by weight of BR-952 and 33 parts by weight of CN1964NS are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0089] Example 5

[0090] Example 5 provides a photocurable resin, which is prepared by the following method: 30 parts by weight of ACMO and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 2.5 parts by weight of photoinitiator TMO, 8 parts by weight of PETMP, 0.15 parts by weight of UV3035, 0.7 parts by weight of OB, 0.2 parts by weight of Tinuvin 292, and 0.8 parts by weight of PTZ are added and dispersed for 60 min; 40 parts by weight of FSP8091 and 25 parts by weight of EM3261 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0091] Example 6

[0092] Example 6 provides a photocurable resin, which is prepared by the following method: 25 parts by weight of IBOA, 10 parts by weight of Genomer*1122 and 0.001 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 2.6 parts by weight of TPO, 0.5 parts by weight of photoinitiator 184, 8 parts by weight of PETMP, 0.1 parts by weight of UV3035, 0.4 parts by weight of FV-100, 0.1 parts by weight of Tinuvin 292 and 0.6 parts by weight of polymerization inhibitor 510 are added and dispersed for 60 min; 30 parts by weight of Genomer*4337 and 30 parts by weight of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0093] Example 7

[0094] Example 7 provides a photocurable resin, which is prepared by the following method: 10 parts by weight of ACMO, 30 parts by weight of IBOA, and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 2.5 parts by weight of TMO, 0.5 parts by weight of photoinitiator 379, 9 parts by weight of PETMP, 0.1 parts by weight of UV3035, 0.5 parts by weight of OB, 0.2 parts by weight of Tinuvin 292, and 0.5 parts by weight of polymerization inhibitor 510 are added and dispersed for 60 min; 20 parts by weight of Genomer*4337 and 25 parts by weight of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0095] Example 8

[0096] Example 8 provides a photocurable resin prepared by the following method: 20 parts by weight of IBOA, 20 parts by weight of TMCHA, and 0.001 parts by weight of ultramarine were added to a container and ultrasonically dispersed for 30 min; 2.6 parts by weight of photoinitiator TMO, 0.6 parts by weight of photoinitiator 184, 5 parts by weight of PETMP, 0.1 parts by weight of UV3035, 0.4 parts by weight of FV-100, 0.1 parts by weight of Tinuvin 292, and 0.5 parts by weight of PTZ were added and dispersed for 60 min; 20 parts by weight of Genomer*4337 and 30 parts by weight of CN1964NS were added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin was obtained.

[0097] Comparative Example 1

[0098] Comparative Example 1 provides a photocurable resin, which is prepared by the following method: 36 parts by weight of TMCHA and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; then 3 parts by weight of photoinitiator 819, 10 parts by weight of PETMP, 0.05 parts by weight of UV3035, 0.8 parts by weight of FV-100, 0.2 parts by weight of Tinuvin 292, and 1 part by weight of PTZ are added and dispersed for 60 min; then 18 parts by weight of Genomer*4337 and 36 parts by weight of BR-952 are added and dispersed for 60 min. After filtration and standing to defoam, the photocurable resin is obtained.

[0099] Comparative Example 2

[0100] Comparative Example 2 provides a photocurable resin, which is prepared by the following method: 36 parts by weight of TMCHA and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 2 parts by weight of photoinitiator 819, 10 parts by weight of PETMP, 0.05 parts by weight of UV3035, 0.8 parts by weight of FV-100, 0.2 parts by weight of Tinuvin 292, and 1 part by weight of PTZ are added and dispersed for 60 min; 18 parts by weight of Genomer*4337 and 36 parts by weight of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0101] Comparative Example 3

[0102] Comparative Example 3 provides a photocurable resin, which is prepared by the following method: 40 parts by mass of ACMO are added to a container and ultrasonically dispersed for 30 min; 3 parts by mass of TMO are added and dispersed for 60 min; 20 parts by mass of Genomer*4337 and 40 parts by mass of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0103] Comparative Example 4

[0104] Comparative Example 4 provides a photocurable resin, which is prepared by the following method: 40 parts by weight of ACMO and 0.002 parts by weight of ultramarine are added to a container and ultrasonically dispersed for 30 min; 3 parts by weight of TMO and 0.2 parts by weight of Tinuvin 292 are added and dispersed for 60 min; 20 parts by weight of Genomer*4337 and 40 parts by weight of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0105] Comparative Example 5

[0106] Comparative Example 5 provides a photocurable resin, which is prepared by the following method: 40 parts by mass of ACMO and 0.002 parts by mass of ultramarine are added to a container and ultrasonically dispersed for 30 min; 6 parts by mass of TMO and 0.2 parts by mass of Tinuvin 292 are added and dispersed for 60 min; 20 parts by mass of Genomer*4337 and 40 parts by mass of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0107] Comparative Example 6

[0108] Comparative Example 6 provides a photocurable resin prepared by the following method: 40 parts by weight of ACMO and 0.002 parts by weight of ultramarine were added to a container and ultrasonically dispersed for 30 min; 3 parts by weight of TMO, 10 parts by weight of PETMP and 0.2 parts by weight of Tinuvin 292 were added and dispersed for 60 min; 20 parts by weight of Genomer*4337 and 40 parts by weight of BR-952 were added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin was obtained.

[0109] Comparative Example 7

[0110] Comparative Example 7 provides a photocurable resin, which is prepared by the following method: 40 parts by mass of ACMO and 0.002 parts by mass of ultramarine are added to a container and ultrasonically dispersed for 30 min; 3 parts by mass of TMO, 0.2 parts by mass of Tinuvin 292, and 1 part by mass of PTZ are added and dispersed for 60 min; 20 parts by mass of Genomer*4337 and 40 parts by mass of BR-952 are added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin is obtained.

[0111] Comparative Example 8

[0112] Comparative Example 8 provides a photocurable resin prepared by the following method: 40 parts by mass of ACMO and 0.002 parts by mass of ultramarine were added to a container and ultrasonically dispersed for 30 min; 3 parts by mass of TMO, 0.2 parts by mass of Tinuvin 292 and 1 part by mass of UV1130 were added and dispersed for 60 min; 20 parts by mass of Genomer*4337 and 40 parts by mass of BR-952 were added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin was obtained.

[0113] Comparative Example 9

[0114] Comparative Example 9 provides a photocurable resin prepared by the following method: 40 parts by mass of ACMO and 0.002 parts by mass of ultramarine were added to a container and ultrasonically dispersed for 30 min; 3 parts by mass of TMO, 1 part by mass of FV-100 and 0.2 parts by mass of Tinuvin 292 were added and dispersed for 60 min; 20 parts by mass of Genomer*4337 and 40 parts by mass of BR-952 were added and dispersed for 60 min; after filtration and standing to defoam, the photocurable resin was obtained.

[0115] The formulations of Examples 1 to 8 above can be found in Table 1 below, and the formulations of Comparative Examples 1 to 9 can be found in Table 2 below.

[0116] Table 1

[0117] Table 2

[0118] Application Examples

[0119] The printing test used a DLP 3D printer with a wavelength of 405nm and a light intensity of 2mW·cm. -1 ~5mW·cm -1 The printing thickness of each layer was set to 30μm, and the illumination time for each layer was 3s.

[0120] The appearance and color are determined by visual inspection.

[0121] Test method for degree of cure: The prepared photocurable resin was coated onto a quartz glass slide with a thickness of 30 μm, and the surface was covered with a release film. The quartz glass slide was then placed on the printer's light platform and set to cure for 3 seconds. The glass slide was removed, the release film was peeled off, and the cured resin film was taken off. The infrared spectrum of the side with the release film and the infrared spectrum of the photocurable resin liquid before curing were scanned using a Fourier transform infrared spectrometer. The spectrum was then processed to obtain the degree of cure.

[0122] Infrared spectrum processing method: 1410 cm⁻¹ -1 Integrate the characteristic absorption peak at the reaction location, and then integrate the standard absorption peak (e.g., 1730 cm⁻¹). -1 The area integral ratio of the two absorption peaks (the carbonyl absorption peak at the carbonyl group) is defined as:

[0123] AU liquid = A liquid (1410cm) -1 ) / A liquid (1730cm) -1 );

[0124] AU sample = A sample (1410cm) -1 ) / A sample (1730cm) -1 );

[0125] Degree of curing = ((AU liquid - AU sample) / AU liquid) * 100%.

[0126] The curable thickness test method is as follows: The prepared photocurable resin is coated onto a quartz glass slide to a thickness of approximately 1 mm. The quartz glass slide is then placed on the printer's light platform and the curing time is set to 3 seconds. The glass slide is then removed, the uncured liquid portion is wiped off, and the thickness of the cured film is measured; this is the curable thickness.

[0127] Test method for the ratio of actual size to set size:

[0128] Import the drawn printing model into the 3D printer, set the exposure time per layer to 3 seconds, and the layer thickness to 30μm, and then print. After printing and cleaning, remove the column and use calipers to measure the actual width of the column, then calculate the value of actual size / set size.

[0129] Model drawing: Use 3D drawing software to draw 64 quadrilaterals with a base of 2mm×2mm and a height of 1cm, evenly arranged in a grid on the plane, with a spacing of 1mm between the columns, and export the model in 3D printing format.

[0130] The photocurable resins prepared in Examples 1-8 and Comparative Examples 1-9 were used for 3D printing using the above testing methods. The test results for Examples 1-8 can be found in Table 3 below, and the test results for Comparative Examples 1-9 can be found in Table 4 below.

[0131] Table 3

[0132] Table 4

[0133] Comparing Examples 1, 2, and 1, the only difference is the type of photoinitiator. It can be observed that TMO and TPO have comparable initiation efficiencies. The curing degree of the sample using TMO is comparable to that using TPO, while the curing depth of the sample using TMO is slightly lower than that using TPO. Photoinitiator 819, due to its excessively high initiation efficiency, resulted in severe light attenuation. At the same addition amount, both the curing degree and curing thickness of the sample decreased significantly, making printing impossible.

[0134] The difference between Comparative Example 2 and Comparative Example 1 lies in the reduced amount of photoinitiator 819. It can be seen that in Comparative Example 2, after reducing the amount of photoinitiator 819, the curing degree, curing thickness, and printing accuracy of the sample are comparable to those of Example 2 (i.e., the sample using TMO), but the sample appears light yellow. Since TPO has reproductive toxicity issues and is listed on the candidate list of substances of very high concern, its application is limited. Therefore, TMO was chosen as the photoinitiator.

[0135] Comparative Example 3 is a pure resin composition without any special additives, which is close to commercially available 3D printing formulations. It can be seen that the pure resin composition without special additives has a weaker ability to absorb light sources, and light can easily penetrate deep into the layers, resulting in a higher curing thickness and lower curing degree. During printing, it is easy for undefined areas to be cured, leading to a serious decrease in printing accuracy. It is not suitable for 3D printing with low layer thickness.

[0136] Compared to Comparative Example 3, Comparative Example 4 only added dye and light stabilizer. It can be seen that after adding dye and light stabilizer, yellowing was better suppressed. After curing, the color changed from light yellow to colorless and transparent, and the curing effect was not significantly affected.

[0137] Comparative Example 5 increased the amount of photoinitiator compared to Comparative Example 4. Increasing the amount of photoinitiator can increase the absorption of ultraviolet light, thereby reducing the curing thickness, but it also brings about the problem of yellowing. At the same time, excessive amount of photoinitiator can also lead to adverse effects such as small molecule migration and reduced mechanical properties.

[0138] Comparative Example 6 added a polyfunctional thiol to Comparative Example 4. The addition of the polyfunctional thiol increased the curing degree at 30μm. Due to the excellent reactivity of the thiol group, the curing activity of the system was increased, thus improving the curing degree. However, at the same time, the curing thickness was increased. Therefore, adding polyfunctional thiol alone is not conducive to improving printing accuracy.

[0139] Comparative Example 7 added a polymerization inhibitor to Comparative Example 4. While some conventional UV-curable resin formulations also include polymerization inhibitors, these are typically added only to increase storage stability, at amounts of approximately 0.01% to 0.5%, which have virtually no impact on curing performance. This application increases the amount of polymerization inhibitor to reduce the cured thickness, but this also affects the degree of curing. Therefore, adding a polymerization inhibitor alone is not beneficial for improving printing accuracy.

[0140] In Examples 1-8, polyfunctional thiols and polymerization inhibitors were added simultaneously, which improved the overall curing rate while suppressing the curing effect at low energy. This improved the degree of curing while reducing the curing thickness, thereby improving printing accuracy.

[0141] Comparative Example 8, based on Comparative Example 4, added a UV absorber. Adding a UV absorber can reduce the cured thickness. However, the UV absorber only absorbs light energy and does not convert energy with the photoinitiator and resin to promote curing. Therefore, while the cured thickness is reduced, the degree of cure is also correspondingly reduced. Nevertheless, adding a UV absorber can effectively reduce the risk of yellowing due to UV aging of the cured sample.

[0142] Comparative Example 9 added a benzoxazole absorbent to Comparative Example 4. By adding the benzoxazole absorbent, the curing thickness can be significantly reduced and the printing accuracy can be adjusted, but the problem of low curing degree still exists.

[0143] Examples 1-8 achieve good printing accuracy by adding polyfunctional thiols to increase the reaction rate and curing degree, adding polymerization inhibitors to suppress the reaction rate at low energy, adding benzoxazole absorbers to increase the curing degree and reduce the curing thickness, and adding small amounts of ultraviolet absorbers, dyes and light stabilizers to adjust the curing thickness.

[0144] In summary, the effect of improving printing accuracy is achieved by comprehensively and synergistically combining the types and amounts of photoinitiators, multifunctional thiols, polymerization inhibitors, benzoxazole absorbers, ultraviolet absorbers, and light stabilizers. In other words, the technical effect produced by this application is achieved by the synergistic effect of each component, while simply adding a single component does not have a significant effect on improving printing accuracy.

[0145] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photocurable resin, wherein, The photocurable resin comprises the following components in parts by weight: The composition includes: 40-70 parts acrylate oligomer, 20-50 parts reactive diluent, 5-20 parts polyfunctional thiols, 0.5-1.5 parts polymerization inhibitor, 1-5 parts photoinitiator, 0-0.5 parts ultraviolet absorber, 0.1-2 parts benzoxazole absorber, 0.001-0.01 parts dye, and 0.1-0.5 parts light stabilizer.

2. The photocurable resin according to claim 1, wherein, The acrylate oligomer is selected from at least one of aliphatic polyurethane acrylate and epoxy acrylate.

3. The photocurable resin according to claim 2, wherein, The acrylate oligomer is selected from at least one of Sartoma CN989, CN1964NS, Changxing Chemical EM3261, Runao Chemical FSP8091, Bomar BR-952, and Rahn Chemical Genomer*4337.

4. The photocurable resin according to claim 1, wherein, The reactive diluent is selected from at least one of monofunctional acrylates or methacrylates, difunctional acrylates or methacrylates, and acrylamide monomers.

5. The photocurable resin according to claim 1, wherein, The polyfunctional thiol is selected from at least one of trimethylolpropane tris(3-mercaptopropionic acid), tris[2-(3-mercaptopropoxy)ethyl]isocyanurate, pentaerythritol tetra(3-mercaptopropionic acid), pentaerythritol tetra(3-mercaptobutyric acid), and dipentaerythritol hexa(3-mercaptopropionic acid).

6. The photocurable resin according to claim 1, wherein, The benzoxazole absorbent is selected from at least one of 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, 2,2-(4,4-stilbeneyl)bisbenzoxazole, 4,4-bis(5-methyl-2-benzoxazolyl)stilbene, 1,4-bis(benzoxazol-2-yl)naphthalene, and Lotte Chemical FV-100.

7. The photocurable resin according to claim 1, wherein, The photoinitiator is selected from at least one of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, 2-isopropylthioxanthone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone.

8. The photocurable resin according to claim 1, wherein, The ultraviolet absorber is selected from at least one of UV3035, UV1130, and UV400.

9. A method for preparing a photocurable resin, wherein, The photocurable resin is as described in any one of claims 1 to 8, and the preparation method includes: Add reactive diluent and dye to the container according to the mass fractions of each component, and ultrasonically disperse for 20 min to 60 min; Continue to add photoinitiator, multifunctional thiol, ultraviolet absorber, benzoxazole absorber, light stabilizer and polymerization inhibitor, and disperse at a speed of 600 r / min to 800 r / min for 40 min to 80 min; Continue adding acrylate oligomers and disperse at a speed of 800-1200 r / min for 40-80 min. After filtration and standing to defoam, the photocurable resin is obtained.

10. The application of a photocurable resin in photocurable 3D printing transparent materials, wherein, The photocurable resin is as described in any one of claims 1 to 8.

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