High-strength dual-curing resin composition for 3D printing as well as preparation method and application of high-strength dual-curing resin composition

Abstract

The invention relates to the technical field of additive manufacturing materials, in particular to a high-strength dual-curing resin composition for 3D printing, a preparation method and application. The dual-cured resin composition is prepared from the following raw materials in parts by weight: 30 to 70 parts of reactive terminated polyurethane acrylate oligomer, 40 to 60 parts of reactive diluent, 3 to 10 parts of thermocuring cross-linking agent, 1 to 6 parts of photoinitiator, 0.1 to 1 part of defoaming agent, 0.1 to 1 part of flatting agent, 0.05 to 2 parts of UV absorbent and 0.1 to 3 parts of nano color paste. On the basis of the dual-curing resin composition, a high-strength three-dimensional molded product (greater than or equal to 30Mpa and the elongation at break greater than or equal to 50%) can be obtained under the condition that the resolution ratio, the printing speed and the efficiency are not influenced. The resin composition has wide application prospects in the fields of aerospace, automobiles, precise instruments, jewelry design and manufacturing, artistic sculpture creation, orthodontic appliances, surgical guide plates, even customized production of skeleton implants and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing materials, and in particular to a high-strength dual-curing resin composition for 3D printing, a preparation method and applications thereof. Background Art

[0002] 3D printing technology has made great breakthroughs in the fields of industry and personal manufacturing. Among them, digital light processing (DLP) photocuring technology, as a high-precision and high-speed 3D printing method, is gradually becoming the preferred solution in many fields such as precision parts manufacturing, prototype design, jewelry casting and biomedicine. DLP photocuring 3D printing technology is an additive manufacturing method based on photopolymerization reaction. It uses a high-resolution DLP projector to project ultraviolet light onto a printing platform containing photosensitive resin, and solidifies the resin layer by layer according to the three-dimensional model generated by the computer, and finally builds a solid model. Compared with the CAD / CAM cutting system, which wastes raw materials more seriously and has shortcomings such as tool wear and dust pollution, DLP 3D printing technology can solidify the entire layer of resin through one exposure, greatly improving the printing speed and efficiency. 3D printing technology has broad application prospects in aerospace, automobiles, precision instruments, jewelry design and manufacturing, creation of artistic sculptures, dental braces, surgical guides, and even customized production of bone implants.

[0003] At present, the main problem with photosensitive resin compositions for 3D printing is that in order to improve resolution, printing speed and efficiency, low molecular weight, low viscosity, high functionality polyurethane acrylate oligomers and reactive diluents need to be used, which leads to greater brittleness of three-dimensional molded products (elongation at break ≤ 15%); in order to improve the toughness of the products, high molecular weight, high viscosity, low functionality polyurethane acrylate oligomers and reactive diluents need to be added, which easily leads to a decrease in the resolution of three-dimensional molded products (horizontal holes and vertical holes are greater than 0.7mm), deterioration in strength (tensile strength ≤ 20%), and a decrease in printing speed and efficiency.

[0004] How to improve product resolution, printing speed and efficiency while ensuring that the three-dimensional molded products have good tensile strength and elongation at break is a problem that needs to be solved urgently. Summary of the invention

[0005] In response to the above-mentioned problems existing in the prior art, the applicant of the present invention provides a high-strength dual-cure resin composition for 3D printing. The three-dimensional molded products prepared based on the resin composition can greatly improve the tensile strength and elongation at break of the three-dimensional molded products while ensuring the resolution, printing speed and efficiency of the products.

[0006] In order to achieve the above object, the present invention first provides a reactive end-capped polyurethane acrylate oligomer, wherein the reactive end-capped polyurethane acrylate oligomer has a structure shown in Formula 1:

[0007]

[0008] In formula 1, n=5-15.

[0009] The present invention also provides a method for preparing the reactive blocked polyurethane acrylate oligomer, comprising the following steps:

[0010] S11. The polyethylene glycol and 4,4-dicyclohexylmethane diisocyanate were mixed and then a catalyst, stannous octoate, was added and heated for reaction;

[0011] S12. tert-butylaminoethyl methacrylate was added dropwise to the reaction system of step S11, and then hydroquinone was added and heated to react;

[0012] S13. Dimethylol propionic acid is added dropwise to the reaction system of step S12, and the reaction is heated;

[0013] S14. Ethyl isocyanate acrylate is added dropwise to the reaction system of step S13, and hydroquinone is added to obtain a reactive blocked polyurethane acrylate oligomer after reaction.

[0014] Furthermore, the polyethylene glycol used in step S11 includes but is not limited to polyethylene glycol 400, polyethylene glycol 600, and polyethylene glycol 800;

[0015] Further, the reaction is carried out under an inert atmosphere; in one embodiment, a nitrogen purge is used.

[0016] In some embodiments of the present invention, polyethylene glycol and 4,4,-dicyclohexylmethane diisocyanate (H12MDI) are added to a nitrogen-purged reactor and stirred for 20 minutes, and then a catalyst, stannous octoate, is added and reacted at 70°C for 3 hours. Then the temperature is lowered to 40°C and tert-butylaminoethyl methacrylate (TBAEMA) is added dropwise, hydroquinone is added again and the reaction is continued at 50°C for 10 hours. Then dimethylol propionic acid (DMPA) is added and reacted at 70°C for 3 hours. Finally, isocyanate ethyl acrylate is added dropwise with a funnel, and hydroquinone is added, and the reaction is cooled to 45°C for 5 hours to obtain a reactive blocked polyurethane acrylate oligomer.

[0017] The second aspect of the present application is to provide a high-strength dual-curing resin composition for 3D printing. The resin composition uses the reactive end-capped polyurethane acrylate oligomer;

[0018] The resin composition comprises the following raw materials in parts by weight:

[0019]

[0020]

[0021] Furthermore, the reactive diluent is a mixture of a first reactive diluent and a second reactive diluent;

[0022] Further, the reactive diluent includes one or more of a monofunctional (meth)acrylate monomer and a difunctional or multifunctional (meth)acrylate monomer;

[0023] In some embodiments of the present invention, the first reactive diluent is β-carboxyethyl acrylate, as shown in the structural formula 2:

[0024] In formula 2, n=1-4.

[0025] Further, the second reactive diluent is a (meth)acrylate monomer different from the first reactive diluent;

[0026] In some preferred embodiments, the ratio of the first reactive diluent to the second reactive diluent is 1:5-1:10.

[0027] In some embodiments, the second reactive diluent specifically includes: n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decaester (meth)acrylate, lauryl (meth)acrylate, lauryl (meth)acrylate, tetrahydrofuran (meth)acrylate, benzyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, ethoxyethoxyethyl acrylate and other (meth)acrylates, isobornyl (meth)acrylate, cyclotrimethylolpropane methylal (meth)acrylate, acryloyl One or more of (meth)acrylates (acrylamides) such as morpholine, N,N-dimethylacrylamide, 1,6-hexanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0028] In some preferred embodiments of the present invention, the second reactive diluent may be one or more of isobornyl (meth)acrylate, acryloylmorpholine, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0029] Furthermore, the heat curing cross-linking agent includes one or a combination of diol, diamine, triol and triamine.

[0030] In some embodiments, the thermal curing crosslinking agent includes ethylene glycol, 1,4-butanediol, methylene dicyclohexylamine (H12MDA; or PACM as a trade name, from Air Products), hydroquinone bis (2-hydroxyethyl) ether (HQEE), 4,4'-methylene bis (3-chloro-2,6-diethylaniline) (MCDEA), 4,4'-methylene-bis-(2,6-diethylaniline) (MDEA), 4,4'-methylene bis (2-chloroaniline) (MOCA).

[0031] In some preferred embodiments of the present invention, the heat curing crosslinking agent is methylene dicyclohexylamine (H12MDA; or PACM as a trade name, from Air Products).

[0032] In some embodiments, the photoinitiator includes an α-hydroxyketone photoinitiator and an acylphosphine oxide photoinitiator; preferably one or more of Ciba's Darocur 1173 photoinitiator, Ciba's Darocur MBF photoinitiator, BASF's Irgacure 184 photoinitiator, BASF's Irgacure 2959 photoinitiator, BASF's Irgacure 907 photoinitiator, BASF's Irgacure 369 photoinitiator, BASF's Irgacure TEPO photoinitiator, BASF's Irgacure TPO photoinitiator, and BASF's Irgacure 819 photoinitiator.

[0033] In some more preferred embodiments, the photoinitiator may be one or more of Darocur 1173 photoinitiator from Ciba, Irgacure 907 photoinitiator from BASF, Irgacure 369 photoinitiator from BASF, Irgacure TEPO photoinitiator from BASF, Irgacure TPO photoinitiator from BASF, and Irgacure 819 photoinitiator from BASF.

[0034] In some embodiments, the defoaming agent includes one or more of a silicone defoaming agent, a polymer defoaming agent and a mineral oil defoaming agent; preferably, the defoaming agent specifically includes one or more of BYK017, BYK018, BYK019, BYK021, BYK022, BYK023, BYK024, BYK025, BYK026, BYK044, BYK065, BYK066, BYK077, BYK088, BYK094, BYK011, BYK012, BYK015, BYK016, BYK055, BYK057, BYK035, BYK037, BYK038, and BYK039.

[0035] In some more preferred embodiments, the defoaming agent may be one or more of BYK022, BYK044, and BYK066.

[0036] Furthermore, the leveling agent includes one or more of organic silicon compounds and acrylic compounds.

[0037] In some embodiments, the leveling agent specifically includes: one or more of BYK300, BYK302, BYK306, BYK307, BYK310, BYK313, BYK320, BYK322, BYK323, BYK326, BYK327, BYK330, BYK331, BYK332, BYK333, BYK342, BYK345, BYK346, BYK347, BYK348, and BYK349.

[0038] In some preferred embodiments of the present invention, the leveling agent may be one or more of BYK330, BYK331, BYK332, etc.

[0039] Furthermore, the UV absorber includes one or more of a benzophenone ultraviolet absorber, a triazine ultraviolet absorber, a benzotriazole ultraviolet absorber, and anthracene ultraviolet absorber.

[0040] In some embodiments, the UV absorber specifically includes one or more of UV-P, UV 400, UV405, UV460, UV 928, UV531, UVS1101, UV1130, UVS1331, UV326, UV328, UV329, UV360, and UV234. In some preferred embodiments of the present invention, the UV absorber is an anthracene ultraviolet absorber, specifically UVS1331 or UVS1101.

[0041] Further, the nano color paste includes one or more of nano silicon dioxide, nano zirconium oxide, nano aluminum oxide, and carbon nanotubes;

[0042] In some preferred embodiments of the present invention, the nano-color paste is nano-silicon dioxide.

[0043] The third aspect of the present invention is to provide a method for preparing the high-strength dual-cure resin composition for 3D printing as described above, comprising the following steps: 30-70 parts of reactive blocked polyurethane acrylate oligomer, 40-60 parts of active diluent, 3-10 parts of thermosetting crosslinking agent, 1-6 parts of photoinitiator, 0.1-1 parts of defoaming agent, 0.1-1 parts of leveling agent, 0.05-2 parts of UV absorber, and 0.1-3 parts of nano-color paste are mixed, stirred and dispersed evenly, and then stored in a dark place.

[0044] Furthermore, the dispersion method adopts a high-speed disperser; further, the rotation speed of the disperser is 500-2500rpm, and the dispersion time is 20-60 minutes.

[0045] A fourth aspect of the present invention is to provide a method for preparing a three-dimensional molded product, the method being based on the dual-cure resin composition described above;

[0046] The preparation method comprises the following steps:

[0047] S21: pouring the dual-cure resin composition evenly into a material tank of a commercially available 3D printing device;

[0048] S22: Construct 3D printing model and parameters and start printing;

[0049] S23: After printing, take out the molded product and place it in ethanol for cleaning for 0.5-5 minutes, and then post-cure it with a 405nm light source for 1-5 minutes;

[0050] S24: The molded product is placed in an oven at 100-120° C. for 8-15 hours to obtain a three-dimensional molded product.

[0051] In one embodiment, the molded product in step S24 is placed in an oven at 110 degrees for 12 hours to obtain a three-dimensional molded product.

[0052] Another aspect of the present invention is to provide a three-dimensional shaped product, wherein the tensile strength of the three-dimensional shaped product is ≥30 MPa and the elongation at break is ≥50%.

[0053] In one embodiment, the curing light source is ultraviolet light with a wavelength of 405 nm;

[0054] In some embodiments, the preparation of a three-dimensional molded product includes the following steps: pouring the dual-cure resin composition evenly into a material tank of a commercially available 3D printing device (405nm light source); constructing a 3D printing model and parameters and starting printing; after printing, taking out the molded product and placing it in ethanol for cleaning for 3 minutes, post-curing it with a 405nm light source for 3 minutes, and then placing it in a 110-degree oven for 12 hours.

[0055] In some embodiments, printing parameters include: layer thickness 50 um, exposure time 2.5 s.

[0056] The present invention also provides the application of the dual-curing resin composition or the three-dimensional molded product, which is applied to the fields of aerospace, automobiles, precision instruments, jewelry design and manufacturing, artistic sculpture creation, dental braces, surgical guides and customized production of bone implants.

[0057] The beneficial effects of this application are at least:

[0058] (1) The present invention first provides a reactive blocked polyurethane acrylate oligomer having a light-heat dual curing effect and high toughness characteristics, and is suitable for preparing 3D printing slurry;

[0059] (2) The present invention further provides a 3D printing resin composition based on a reactive blocked polyurethane acrylate oligomer. The three-dimensional molded product prepared based on the high-strength dual-curing resin composition for 3D printing provided by the present invention has high resolution (both the horizontal hole and the vertical hole are not more than 0.5 mm); high strength (tensile strength ≥30Mpa and elongation at break ≥50%); and high printing speed (exposure time 2.5s);

[0060] (3) The preparation method of the 3D printing resin composition and the three-dimensional molded product has a simple process and is suitable for the fields of aerospace, automobile, precision instrument, jewelry design and manufacturing, artistic sculpture creation, dental braces, surgical guides, and even customized production of bone implants. DETAILED DESCRIPTION

[0061] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0062] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0063] Performance testing method:

[0064] Tensile strength test: refer to GB / T 1040-92 "Test method for tensile properties of plastics" to test the tensile strength and elongation at break of the samples prepared in the examples and comparative examples;

[0065] Resolution test method: pour the dual-cure resin composition into a commercially available 3D printing device; construct a 3D printing model and parameters and print (the printing model must include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S); test the minimum aperture that can achieve a clear and complete printing effect.

[0066] Embodiment 1 Synthesis Example 1 of Reactive Blocked Polyurethane Prepolymer:

[0067] 200 grams of polyethylene glycol 400 (PEG400) dried under vacuum was added to a four-necked flask with a stirrer, nitrogen purge and thermometer. Then 131 grams of 4,4,-dicyclohexylmethane diisocyanate (H12MDI) was added to the flask and stirred for 20 minutes, followed by the addition of 50 microliters of tin (II) catalyst stannous octoate. The temperature was raised to 70°C and the reaction was maintained for 3 hours. The temperature was then gradually lowered to 40°C and 92.6 grams of tert-butylaminoethyl methacrylate (TBAEMA) was gradually added over 20 minutes using a funnel, the temperature was then set to 50°C and 100 ppm of hydroquinone was added, and the reaction was allowed to continue for 10 hours. Then 128 grams of dimethylol propionic acid (DMPA) was gradually added over 30 minutes using a funnel, the temperature was raised to 70°C, and the reaction was maintained for 3 hours. Finally, 70.5 g of 2-isocyanatoethyl acrylate was gradually added using a funnel over 20 minutes, and 100 ppm of hydroquinone was added, and the temperature was lowered to 45° C. to keep the reaction for 5 hours. The final liquid was poured out as product A1.

[0068] Embodiment 2 Synthesis Example 2 of Reactive Blocked Polyurethane Prepolymer:

[0069] 300 grams of polyethylene glycol 600 (PEG600) dried under vacuum was added to a four-necked flask with a stirrer, nitrogen purge and thermometer. Then 131 grams of 4,4,-dicyclohexylmethane diisocyanate (H12MDI) was added to the flask and stirred for 20 minutes, followed by the addition of 50 microliters of tin (II) catalyst stannous octoate. The temperature was raised to 70°C and the reaction was maintained for 3 hours. The temperature was then gradually lowered to 40°C and 92.6 grams of tert-butylaminoethyl methacrylate (TBAEMA) was gradually added over 20 minutes using a funnel, the temperature was then set to 50°C and 100 ppm of hydroquinone was added, and the reaction was allowed to continue for 10 hours. Then 128 grams of dimethylol propionic acid (DMPA) was gradually added over 30 minutes using a funnel, the temperature was raised to 70°C, and the reaction was maintained for 3 hours. Finally, 70.5 g of 2-isocyanatoethyl acrylate was gradually added using a funnel over 20 minutes, and 100 ppm of hydroquinone was added, and the temperature was lowered to 45° C. to keep the reaction for 5 hours. The final liquid was poured out as product A2.

[0070] Embodiment 3 Synthesis Example 3 of Reactive Blocked Polyurethane Prepolymer:

[0071] 400 grams of vacuum dried polyethylene glycol 800 (PEG800) was added to a four-necked flask with a stirrer, nitrogen purge and thermometer. Then 131 grams of 4,4,-dicyclohexylmethane diisocyanate (H12MDI) was added to the flask and stirred for 20 minutes, followed by the addition of 50 microliters of tin (II) catalyst stannous octoate. The temperature was raised to 70°C and the reaction was maintained for 3 hours. The temperature was then gradually lowered to 40°C and 92.6 grams of tert-butylaminoethyl methacrylate (TBAEMA) was gradually added over 20 minutes using a funnel, the temperature was then set to 50°C and 100 ppm of hydroquinone was added, and the reaction was allowed to continue for 10 hours. Then 128 grams of dimethylol propionic acid (DMPA) was gradually added over 30 minutes using a funnel, the temperature was raised to 70°C, and the reaction was maintained for 3 hours. Finally, 70.5 g of 2-isocyanatoethyl acrylate was gradually added using a funnel over 20 minutes, and 100 ppm of hydroquinone was added, and the temperature was lowered to 45° C. to keep the reaction for 5 hours. The final liquid was poured out as product A3.

[0072] The present invention is described in detail below. The raw materials and the amounts of raw materials used in each example are shown in Table 1.

[0073] Table 1: Allocation ratio of each group in the embodiment

[0074]

[0075] * 1β-CEA: n = 2; * 2 DPGDA: dipropylene glycol diacrylate;* 3 Methylenedicyclohexylamine (H12MDA; PACM as a trade name, from Air Products)

[0076] Example 4

[0077] A method for preparing a three-dimensional molded product of a high-strength dual-curing resin composition for 3D printing, the preparation method comprising the following steps:

[0078] 50 parts of reactive blocked polyurethane acrylate oligomer A1, 5.5 parts of active diluent β-CEA, 40.5 parts of difunctional active diluent DPGDA, 6.5 parts of heat curing crosslinking agent PACM, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331 and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the low-viscosity and high-performance dual-curing resin composition for 3D printing was prepared.

[0079] The method for preparing a three-dimensional formed product comprises the following steps:

[0080] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0081] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0082] S13: After printing, take out the molded product and place it in ethanol for cleaning for 3 minutes, and then cure it with a 405nm light source for 3 minutes;

[0083] S14: The molded product is placed in an oven at 110 degrees for 12 hours.

[0084] Example 5

[0085] A method for preparing a three-dimensional molded product of a high-strength dual-curing resin composition for 3D printing, the preparation method comprising the following steps:

[0086] 50 parts of reactive blocked polyurethane acrylate oligomer A2, 5.5 parts of active diluent β-CEA, 40.5 parts of difunctional active diluent DPGDA, 6.5 parts of heat curing crosslinking agent PACM, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331 and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the low-viscosity and high-performance dual-curing resin composition for 3D printing was prepared.

[0087] The method for preparing a three-dimensional formed product comprises the following steps:

[0088] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0089] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0090] S13: After printing, take out the molded product and place it in ethanol for cleaning for 3 minutes, and then use a 405nm light source to post-cure for 3 minutes; S14: The molded product is placed in a 110 degree oven for 12 hours.

[0091] Example 6

[0092] A method for preparing a three-dimensional molded product of a high-strength dual-curing resin composition for 3D printing, the preparation method comprising the following steps:

[0093] 50 parts of reactive blocked polyurethane acrylate oligomer A3, 5.5 parts of active diluent β-CEA, 40.5 parts of difunctional active diluent DPGDA, 6.5 parts of heat curing crosslinking agent PACM, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331 and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the low-viscosity and high-performance dual-curing resin composition for 3D printing was prepared.

[0094] The method for preparing a three-dimensional formed product comprises the following steps:

[0095] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0096] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0097] S13: After printing, take out the molded product and place it in ethanol for cleaning for 3 minutes, and then use a 405nm light source to post-cure for 3 minutes; S14: The molded product is placed in a 110 degree oven for 12 hours.

[0098] Example 7

[0099] A method for preparing a three-dimensional molded product of a high-strength dual-curing resin composition for 3D printing, the preparation method comprising the following steps:

[0100] 40 parts of reactive blocked polyurethane acrylate oligomer A2, 7.5 parts of active diluent β-CEA, 48 parts of difunctional active diluent DPGDA, 6.5 parts of heat curing crosslinking agent PACM, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331, and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the low-viscosity and high-performance dual-curing resin composition for 3D printing was prepared.

[0101] The method for preparing a three-dimensional formed product comprises the following steps:

[0102] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0103] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0104] S13: After printing, take out the molded product and place it in ethanol for cleaning for 3 minutes, and then cure it with a 405nm light source for 3 minutes;

[0105] S14: The molded product is placed in an oven at 110 degrees for 12 hours.

[0106] Example 8

[0107] A method for preparing a three-dimensional molded product of a high-strength dual-curing resin composition for 3D printing, the preparation method comprising the following steps:

[0108] 60 parts of reactive blocked polyurethane acrylate oligomer A2, 4.0 parts of active diluent β-CEA, 32 parts of difunctional active diluent DPGDA, 6.5 parts of heat curing crosslinking agent PACM, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331, and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the low-viscosity and high-performance dual-curing resin composition for 3D printing was prepared.

[0109] The method for preparing a three-dimensional formed product comprises the following steps:

[0110] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0111] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0112] S13: After printing, take out the molded product and place it in ethanol for cleaning for 3 minutes, and then cure it with a 405nm light source for 3 minutes;

[0113] S14: The molded product is placed in an oven at 110 degrees for 12 hours.

[0114] Comparative Example 1

[0115] A method for preparing a three-dimensional molded product of a photosensitive resin composition for 3D printing, the preparation method comprising the following steps:

[0116] 50 parts of polyurethane acrylate oligomer CN983NS, 45 parts of difunctional active diluent DPGDA, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331, and 0.2 parts of nano-silica color paste were mixed, and stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the 3D printing photosensitive resin composition was prepared.

[0117] The method for preparing a three-dimensional formed product comprises the following steps:

[0118] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0119] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0120] S13: After printing is completed, the molded product is taken out and placed in ethanol for cleaning for 3 minutes, and then cured for 3 minutes using a 405nm light source.

[0121] Comparative Example 2

[0122] A method for preparing a three-dimensional molded product of a photosensitive resin composition for 3D printing, the preparation method comprising the following steps:

[0123] 50 parts of reactive blocked polyurethane acrylate oligomer A2, 45 parts of difunctional active diluent DPGDA, 1 part of photoinitiator 1173, 2.5 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.1 parts of UV absorber UVS1331, and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser to obtain the 3D printing photosensitive resin composition.

[0124] The method for preparing a three-dimensional formed product comprises the following steps:

[0125] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0126] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0127] S13: After printing, take out the molded product and place it in ethanol for cleaning for 3 minutes, and then use a 405nm light source to post-cure for 3 minutes. Comparative Example 3: Previous Patent - Photocuring High-Resolution Photosensitive Resin Composition

[0128] The method for preparing the resin composition comprises the following steps:

[0129] 35 parts of difunctional polyurethane acrylate oligomer CN983NS, 15 parts of nonafunctional polyurethane acrylate oligomer CN9013NS, 40 parts of difunctional reactive diluent DPGDA, 10 parts of tetrafunctional reactive diluent PETTA, 3 parts of photoinitiator TPO, 0.25 parts of defoamer BYK066, 0.25 parts of leveling agent BYK332, 0.2 parts of UV absorber UVS1331, and 0.2 parts of nano-silica color paste were mixed, and then stirred and dispersed at a speed of 1500 rpm for 40 minutes using a high-speed disperser; the high-resolution photosensitive resin composition for 3D printing was prepared.

[0130] The method for preparing a three-dimensional formed product comprises the following steps:

[0131] S11: Pour the photosensitive resin composition evenly into a material tank of a commercially available 3D printing device (405 nm light source);

[0132] S12: Build a 3D printing model and parameters and start printing (the printing model needs to include vertical and horizontal holes of 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm; printing parameters: layer thickness 50um, exposure time 2.5S);

[0133] S13: After printing is completed, the molded product is taken out and placed in ethanol for cleaning for 3 minutes, and then cured for 3 minutes using a 405nm light source.

[0134] Performance test results:

[0135] The three-dimensional formed products obtained in Examples 4-8 of the present invention and Comparative Examples 1-3 were tested for tensile strength and elongation at break, and the resolution and printing effect were observed. The test results are shown in Table 2.

[0136] Table 2

[0137]

[0138] From the test results in Table 2, we can see that:

[0139] The three-dimensional formed products prepared in Examples 4-8 of the present invention have both high strength (tensile strength ≥30Mpa and elongation at break ≥50%) and high resolution (both the horizontal hole and the vertical hole do not exceed 0.5mm); among them, the tensile strength of Example 2 can reach 37.5Mpa and the elongation at break 63.2%, and the resolution of the vertical hole can reach 0.4mm. At the same time, it has an efficient printing speed (exposure time 2.5s), and is suitable for aerospace, automobile, precision instrument, jewelry design and manufacturing, creation of artistic sculptures, dental braces, surgical guides, and even customized production of bone implants.

[0140] However, the performance of the three-dimensional molded products prepared in Comparative Examples 1-2 cannot fully meet the requirements. The three-dimensional molded product prepared in Comparative Example 1 is hard and brittle (high tensile strength and very low elongation at break) and is easy to crack. Although the three-dimensional molded product prepared in Comparative Example 2 has relatively good elongation at break and efficient printing speed, it has low tensile strength, poor printing effect and low resolution. Although the three-dimensional molded product prepared in Comparative Example 3 has high resolution and high tensile strength, and the printing speed is also fast, the elongation at break is very low and cannot meet the application scenarios with high toughness requirements.

[0141] In summary, the present invention synthesizes reactive blocked polyurethane acrylate oligomers, adds a thermosetting crosslinking agent, and then compounding β-carboxyethyl acrylate, and uses dual curing technology to obtain high-strength (tensile strength ≥30Mpa and elongation at break ≥50%) three-dimensional molded products without affecting resolution, printing speed and efficiency.

[0142] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. Application of a reactive blocked polyurethane acrylate oligomer in a 3D printing resin composition, characterized in that: It has the structure shown in formula 1: In formula 1, n=5-15.

2. A high-strength dual-curing resin composition for 3D printing, characterized in that: Using the reactive blocked polyurethane acrylate oligomer according to claim 1; The invention comprises the following raw materials in parts by weight:

3. The high-strength dual-curing resin composition for 3D printing according to claim 2, characterized in that: The active diluent is a mixture of a first active diluent and a second active diluent; The first active diluent is β-carboxyethyl acrylate, as shown in the structural formula 2: In formula 2, n=1-4.

4. The high-strength dual-curing resin composition for 3D printing according to claim 3, characterized in that: The second reactive diluent is a (meth)acrylate monomer different from the first reactive diluent; The ratio of the first active diluent to the second active diluent is 1:5-1:

10.

5. The high-strength dual-curing resin composition for 3D printing according to claim 2, characterized in that: The photoinitiator includes α-hydroxy ketone photoinitiator and acylphosphine oxide photoinitiator; And / or, the defoamer includes one or more of an organosilicon defoamer, a polymer defoamer and a mineral oil defoamer; And / or, the leveling agent includes one or more of an organosilicon compound and an acrylic compound; And / or, the heat curing cross-linking agent includes one or a combination of diol, diamine, triol, triamine or the like.

6. The high-strength dual-curing resin composition for 3D printing according to claim 2, characterized in that: The UV absorber includes one or more of a benzophenone type UV absorber, a triazine type UV absorber, a benzotriazole type UV absorber, and anthracene type UV absorber; And / or, the nano-color paste includes one or more of nano-silicon dioxide, nano-zirconium oxide, nano-aluminum oxide, and carbon nanotubes.

7. The method for preparing the high-strength dual-curing resin composition for 3D printing according to any one of claims 2 to 6, characterized in that: The steps include: Reactive end-capped polyurethane acrylate oligomer 30-70 parts, active diluent 40-60 parts, thermosetting crosslinking agent 3-10 parts, photoinitiator 1-6 parts, defoamer 0.1-1 parts, leveling agent 0.1-1 parts, UV absorber 0.05-2 parts, nano color paste 0.1-3 parts, mix and stir to disperse evenly, then store in a dark place.

8. A method for preparing a three-dimensional formed product, characterized in that: Using the dual-cure resin composition according to any one of claims 2 to 6 or the dual-cure resin composition prepared by the preparation method according to claim 7; The preparation method comprises the following steps: S21: pouring the dual-cure resin composition evenly into a material tank of a commercially available 3D printing device; S22: Construct 3D printing model and parameters and start printing; S23: After printing, take out the molded product and place it in ethanol for cleaning for 0.5-5 minutes, and then post-cure it with a 405nm light source for 1-5 minutes; S24: The molded product is placed in an oven at 100-120°C for 8-15 hours.

9. The three-dimensional shaped product obtained by the method of claim 8, characterized in that: The three-dimensional formed product has a tensile strength of ≥30 MPa and an elongation at break of ≥50%.

10. Use of the dual-cure resin composition according to any one of claims 2 to 6, or use of the three-dimensional molded product according to claim 9, characterized in that: It is used in aerospace, automobile, precision instrument, jewelry design and manufacturing, art sculpture creation, dental braces, surgical guides and customized production of bone implants.

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