Photocuring elastomer, and preparation method, use method and application thereof

Abstract

The invention relates to a light-cured elastomer as well as a preparation method, a use method and application thereof. The preparation raw materials of the photocuring elastomer comprise the following components: a hyperbranched polyurethane acrylate composition, epoxy resin, an active diluting monomer and a photoinitiator, the hyperbranched polyurethane acrylate composition is prepared from first hyperbranched polyurethane acrylate, second hyperbranched polyurethane acrylate and third hyperbranched polyurethane acrylate; the branching degree of the first hyperbranched polyurethane acrylate is 0.6 to 0.7, the branching degree of the second hyperbranched polyurethane acrylate is 0.8 to 0.89, and the branching degree of the third hyperbranched polyurethane acrylate is 0.9 to 1.0. The photosensitive resin material with high printing precision, high elasticity, high flexibility and relatively high tensile strength is obtained by screening the preparation raw materials of the photocuring elastomer.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a photocurable elastomer and its preparation method, usage method and application. Background Technology

[0002] Photocurable elastomers are widely used in the field of photocurable 3D printing due to their advantages of rapid curing and low VOC emissions. For example, CN119462718A discloses a photosensitive functional monomer and a method for preparing photocurable 3D printed polyurethane elastomers using it. CN119751885A discloses a photocurable 3D printed thermoplastic elastomer material, specifically using styrene-butadiene-styrene block copolymer (SBS) and a multi-thiol crosslinking agent as the matrix, and thiol as a solvent diluent to adjust the viscosity of the system. CN120424274A discloses a photocurable 3D printing composition that reduces light scattering by adding polyether-based polyurethane acrylate oligomers containing urea bonds, based on weaker intermolecular forces.

[0003] However, existing technologies have significant bottlenecks: First, the crosslinking density of traditional linear photocurable elastomers is difficult to control, resulting in either insufficient elasticity and poor solvent resistance, or hardness and brittleness that are prone to breakage; Second, single-type elastomers have poor compatibility with epoxy resins, and are prone to phase separation after mixing, leading to uneven mechanical properties of the cured material and failing to adapt to the high-efficiency characteristics of photocuring; Third, the material performance parameters are fixed, which can only meet the needs of a single scenario and are difficult to cover the differentiated requirements of "elasticity-adhesion-temperature resistance" in multiple fields, thus limiting the scope of application.

[0004] For example, the crosslinking density of linear polyurethane acrylate (PUA) photocurable elastomers commonly used in the prior art depends on the control of a single crosslinking agent. If the amount of crosslinking agent is small, the solvent resistance is poor (the mass change rate after 24 hours of acetone immersion is often >8%), and if the amount is large, the material is hard and brittle (the elongation at break is <50%). Moreover, when this type of linear PUA is mixed with epoxy resin, due to the large difference in solubility parameters, it will delaminate after standing for 4 hours, and the local tensile strength deviation of the cured material is >30%.

[0005] Therefore, how to prepare photosensitive resins that combine high elasticity, low viscosity, and good mechanical strength has become a key problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a photocurable elastomer and its preparation method, usage method, and applications. The present invention prepares polyurethane acrylate oligomers with a branching degree gradient of 0.6-1.0 by screening multifunctional branched backbone raw materials, rigid acrylate monomers, and flexible polyether segment raw materials. Rigid groups grafted at the low-branched ends (0.6-0.8) enhance tensile strength, while flexible segments retained at the high-branched ends (0.8-1.0) ensure elastic recovery. Simultaneously, the gradient branching structure reduces molecular chain entanglement to lower viscosity (controlled within a reasonable printing range at 25℃). Ultimately, a photosensitive resin material with high printing accuracy, high elasticity (elongation at break ≥50%), high flexibility, and relatively high tensile strength (≥8MPa) is obtained.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a photocurable elastomer, wherein the raw materials for preparing the photocurable elastomer include the following components: a hyperbranched polyurethane acrylate composition, an epoxy resin, a reactive diluent monomer, and a photoinitiator; the hyperbranched polyurethane acrylate composition includes a first hyperbranched polyurethane acrylate, a second hyperbranched polyurethane acrylate, and a third hyperbranched polyurethane acrylate; the degree of branching of the first hyperbranched polyurethane acrylate is 0.6-0.7 (e.g., 0.62, 0.64, 0.65, 0.66, or 0.68, etc.), the degree of branching of the second hyperbranched polyurethane acrylate is 0.8-0.89 (e.g., 0.82, 0.84, 0.85, 0.86, or 0.88, etc.), and the degree of branching of the third hyperbranched polyurethane acrylate is 0.9-1.0 (e.g., 0.92, 0.94, 0.95, 0.96, or 0.98, etc.).

[0009] In this invention, the long-chain polyols (PPG2000 / PTMG2000) of the low-branched first hyperbranched polyurethane acrylate (HPUA-1) retain flexibility and ensure elongation at break; the multifunctional monomers (TMP / PER) of the highly branched third hyperbranched polyurethane acrylate (HPUA-3) provide rigid branching points and enhance tensile strength; the medium-branched second hyperbranched polyurethane acrylate (HPUA-2) balances the two, achieving a synergistic effect of "high elasticity (elongation at break ≥320%) + high strength (tensile strength ≥12.5MPa)," breaking through the bottleneck of traditional elastomers where "elasticity and strength cannot be achieved simultaneously."

[0010] In this invention, the formula for calculating the degree of branching is as follows: DB=(B+T) / (B+L+T).

[0011] Wherein, B represents the number of branched units in the molecule (referring to structural units with 3 or more connection points, such as units formed by multifunctional monomers such as trimethylolpropane and pentaerythritol); L represents the number of linear units (structural units with only 2 connection points, such as segments formed by diols and diisocyanates); and T represents the number of terminal units (structural units with only 1 connection point, such as terminal groups formed by end capping agents).

[0012] Preferably, the hyperbranched polyurethane acrylate composition comprises the following components in parts by weight: 3-4 parts of first hyperbranched polyurethane acrylate (e.g., 3.2, 3.4, 3.5, 3.6, or 3.8 parts, etc.), 1-2 parts of second hyperbranched polyurethane acrylate (e.g., 1.2, 1.4, 1.5, 1.6, or 1.8 parts, etc.), and 1 part of third hyperbranched polyurethane acrylate.

[0013] Preferably, the epoxy resin includes glycidylamine type epoxy resin and / or bisphenol F type epoxy resin.

[0014] In this invention, a hyperbranched polyurethane acrylate composition (HUPA) is combined with an epoxy resin of a specific structure to form an interpenetrating network with synergistic effects. After mixing HPUA and epoxy resin, on the one hand, an interpenetrating network is formed through hydrogen bonding, reducing interfacial tension and thus preventing phase separation; on the other hand, the rigid segments of epoxy and the flexible segments of HPUA complement each other, forming a dense network that further reduces solvent penetration. This solves the problem of "easy phase separation between elastomer and epoxy," and improves mechanical uniformity (no localized fractures) and solvent resistance (mass change rate after acetone immersion ≤1.8%).

[0015] Preferably, the glycidylamine type epoxy resin includes TDE-85 and / or AG-80.

[0016] Preferably, the bisphenol F type epoxy resin includes DER 438.

[0017] Preferably, the reactive diluent monomer comprises any one or a combination of at least two of tripropylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, or 1,6-hexanediol diacrylate.

[0018] Preferably, the photoinitiator includes Irgacure 2959 and / or Irgacure 184D.

[0019] Preferably, the raw materials for preparing the photocurable elastomer include the following components in parts by weight: 55-70 parts of hyperbranched polyurethane acrylate composition, 5-10 parts of epoxy resin, 15-25 parts of reactive diluent monomer, and 1-2 parts of photoinitiator.

[0020] The weight parts of the hyperbranched polyurethane acrylate composition may be, for example, 58 parts, 60 parts, 63 parts, 65 parts, or 68 parts.

[0021] The epoxy resin may be present in parts by weight of, for example, 6, 7, 7.5, 8, or 9 parts.

[0022] The weight fractions of the active diluent monomer can be, for example, 16, 18, 20, 22, or 24 parts.

[0023] The weight percentage of the photoinitiator can be, for example, 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, or 1.8 parts.

[0024] Preferably, the raw materials for preparing the photocurable elastomer also include a toughening agent.

[0025] Preferably, the toughening agent comprises a core-shell structured acrylate toughening agent and / or a carboxyl-terminated liquid nitrile rubber.

[0026] Preferably, the core-shell structured acrylate toughening agent includes Kane Ace MX-154.

[0027] Preferably, the number average molecular weight of the terminal carboxyl liquid nitrile rubber is 2800-3200 g / mol, for example, it can be 2900 g / mol, 2950 g / mol, 3000 g / mol, 3050 g / mol or 3100 g / mol.

[0028] Preferably, the toughening agent is present in 0.3-0.5 parts by weight, for example, 0.32 parts, 0.35 parts, 0.4 parts, 0.45 parts or 0.48 parts, etc.

[0029] Preferably, the raw materials for preparing the photocurable elastomer also include a leveling agent.

[0030] Preferably, the leveling agent comprises Evonik's TEGO Flow 370 and / or Evka's EFKA-3777.

[0031] Preferably, the leveling agent is present in a weight ratio of 0.05-0.08 parts, for example, 0.055 parts, 0.06 parts, 0.065 parts, 0.07 parts or 0.075 parts, etc.

[0032] Preferably, the raw materials for preparing the photocurable elastomer further include pigment paste.

[0033] Preferably, the pigment paste includes UK-9007 and / or BASF Irgazin Red L 3695.

[0034] Preferably, the pigment paste is in the form of 0.2-0.4 parts by weight, for example, 0.23 parts, 0.25 parts, 0.3 parts, 0.35 parts or 0.37 parts, etc.

[0035] Preferably, the raw materials for preparing the photocurable elastomer further include a polymerization inhibitor.

[0036] Preferably, the polymerization inhibitor comprises p-hydroxyacetophenone and / or 2,6-di-tert-butyl-p-cresol.

[0037] Preferably, the polymerization inhibitor is present in 0.05-0.1 parts by weight, for example, 0.06 parts, 0.07 parts, 0.075 parts, 0.08 parts or 0.09 parts, etc.

[0038] Preferably, the raw materials for preparing the photocurable elastomer further include functional fillers.

[0039] Preferably, the functional filler further includes graphene nanosheets and / or multi-walled carbon nanotubes.

[0040] Preferably, the graphene nanosheets are a single layer.

[0041] Preferably, the thickness of the graphene nanosheet is less than 5 nm, for example, it can be 1 nm, 2 nm, 3 nm, 3.5 nm or 4 nm, etc.

[0042] Preferably, the diameter of the multi-walled carbon nanotubes is 10-20 nm, for example, it can be 12 nm, 14 nm, 15 nm, 16 nm or 18 nm.

[0043] Preferably, the functional filler is 1-3 parts by weight, for example, 1.5 parts, 1.8 parts, 2 parts, 2.3 parts or 2.5 parts, etc.

[0044] This invention utilizes a three-in-one additive combination of single-layer graphene nanosheets, a core-shell toughening agent, and a leveling agent, balancing mechanical properties and printing accuracy. The use of single-layer graphene nanosheets prevents agglomeration, the core-shell toughening agent enhances tear strength without increasing viscosity, and the leveling agent reduces surface tension. Combined with an 80-120 mesh filter, this achieves a synergistic effect of "high mechanical strength + high printability," solving the problem of "viscosity spikes and clogging after adding fillers."

[0045] Preferably, the raw materials for preparing the photocurable elastomer further include a curing agent.

[0046] Preferably, the curing agent includes any one or a combination of at least two of polyamide 650, polyetheramine D230, BASF EC301, or Evonik 2910.

[0047] Preferably, the curing agent is in the form of 5-8 parts by weight, for example, 5.5 parts, 6 parts, 6.5 parts, 7 parts or 7.5 parts, etc.

[0048] Preferably, the raw materials for preparing the first hyperbranched polyurethane acrylate each independently comprise the following components in parts by weight: 4.2-14 parts of a multifunctional monomer (e.g., 5, 7, 9, 11, or 13 parts, etc.), 17.5-47.35 parts of diisocyanate (e.g., 20, 25, 30, 35, or 40 parts, etc.), 15-73 parts of polyol (e.g., 20, 30, 40, 50, or 60 parts, etc.), and 0.0001-0.001 parts of catalyst (e.g., 0.0002, 0.0004, 0.0...). The raw materials for preparing the first polyurethane acrylate include 0.006 parts, 0.0008 parts, or 0.0009 parts, etc.), 5.2-23.6 parts of end-capping agent (e.g., 10 parts, 12 parts, 15 parts, 18 parts, or 20 parts, etc.), 0.05-0.2 parts of polymerization inhibitor (e.g., 0.08 parts, 0.1 parts, 0.12 parts, 0.15 parts, or 0.18 parts, etc.), and 15-25 parts of solvent (e.g., 17 parts, 19 parts, 20 parts, 22 parts, or 24 parts, etc.). The polyfunctional monomers in the raw materials for preparing the first polyurethane acrylate include trimethylolpropane, and the polyols include polypropylene glycol and / or polytetrahydrofuran glycol.

[0049] Preferably, the number average molecular weight of the polyol in the raw material for preparing the first polyurethane acrylate is 1800-2200 g / mol, for example, it can be 1900 g / mol, 1950 g / mol, 2000 g / mol, 2050 g / mol or 2100 g / mol.

[0050] Preferably, the raw materials for preparing the second hyperbranched polyurethane acrylate each independently comprise the following components in parts by weight: 4.2-14 parts of a multifunctional monomer (e.g., 5, 7, 9, 11, or 13 parts, etc.), 17.5-47.35 parts of diisocyanate (e.g., 20, 25, 30, 35, or 40 parts, etc.), 15-73 parts of polyol (e.g., 20, 30, 40, 50, or 60 parts, etc.), and 0.0001-0.001 parts of catalyst (e.g., 0.0002, 0.0004, 0.00...). The raw materials for preparing the second polyurethane acrylate include: 0.06 parts, 0.0008 parts, or 0.0009 parts, etc.); 5.2-23.6 parts of end-capping agent (e.g., 10 parts, 12 parts, 15 parts, 18 parts, or 20 parts, etc.); 0.05-0.2 parts of polymerization inhibitor (e.g., 0.08 parts, 0.1 parts, 0.12 parts, 0.15 parts, or 0.18 parts, etc.); and 15-25 parts of solvent (e.g., 17 parts, 19 parts, 20 parts, 22 parts, or 24 parts, etc.). The polyfunctional monomers in the raw materials for preparing the second polyurethane acrylate include pentaerythritol and trimethylolpropane, and the polyols include polypropylene glycol and / or polycaprolactone.

[0051] Preferably, the mass ratio of pentaerythritol to trimethylolpropane is 1:(2-3), for example, it can be 1:2.2, 1:2.4, 1:2.5, 1:2.6 or 1:2.8, etc.

[0052] Preferably, the number average molecular weight of the polyol in the raw material for preparing the second polyurethane acrylate is 800-1200 g / mol, for example, it can be 900 g / mol, 950 g / mol, 1000 g / mol, 1050 g / mol or 1100 g / mol.

[0053] Preferably, the raw materials for preparing the third hyperbranched polyurethane acrylate each independently comprise the following components in parts by weight: 4.2-14 parts of multifunctional monomer (e.g., 5, 7, 9, 11, or 13 parts, etc.), 17.5-47.35 parts of diisocyanate (e.g., 20, 25, 30, 35, or 40 parts, etc.), 15-73 parts of polyol (e.g., 20, 30, 40, 50, or 60 parts, etc.), and 0.0001-0.001 parts of catalyst (e.g., 0.0002, 0.0004, 0.0005, 0.0006, 0.0007, 0.0008, 0.0009, 0.0001 ... The raw materials for preparing the third polyurethane acrylate include: 0.0006 parts, 0.0008 parts, or 0.0009 parts, etc.); 5.2-23.6 parts of end-capping agent (e.g., 10 parts, 12 parts, 15 parts, 18 parts, or 20 parts, etc.); 0.05-0.2 parts of polymerization inhibitor (e.g., 0.08 parts, 0.1 parts, 0.12 parts, 0.15 parts, or 0.18 parts, etc.); and 15-25 parts of solvent (e.g., 17 parts, 19 parts, 20 parts, 22 parts, or 24 parts, etc.). The multifunctional monomers in the raw materials for preparing the third polyurethane acrylate include pentaerythritol and trimethylolpropane, and the polyols include polycaprolactone.

[0054] Preferably, the mass ratio of pentaerythritol to trimethylolpropane is 1:(0.5-1), for example, it can be 1:0.6, 1:0.7, 1:0.75, 1:0.8 or 1:0.9, etc.

[0055] Preferably, the number average molecular weight of the polyol in the raw material for preparing the third polyurethane acrylate is 400-600 g / mol, for example, it can be 420 g / mol, 450 g / mol, 500 g / mol, 530 g / mol or 550 g / mol.

[0056] Preferably, the preparation methods of the first, second, and third hyperbranched polyurethane acrylates each independently include the following steps:

[0057] (1) Mix a portion of the solvent with a multifunctional monomer, and add the mixture dropwise to a mixture of diisocyanate, the remaining solvent and a portion of the catalyst to carry out a prepolymerization reaction to obtain a hyperbranched prepolymer;

[0058] (2) The hyperbranched prepolymer is mixed with the remaining catalyst and polyol and subjected to polymerization to obtain the hyperbranched polymer;

[0059] (3) The hyperbranched polymer is mixed with a mixture of a polymerization inhibitor and a portion of the end-capping agent to carry out the first end-capping reaction, and then the remaining end-capping agent is added dropwise to carry out the second end-capping reaction to obtain the hyperbranched polyurethane acrylate.

[0060] In this invention, the addition of the multifunctional monomer in step (1) and the addition of the capping agent in step (3) can avoid local gelation, ensure complete reaction of -NCO, and eliminate toxic residues during storage. Furthermore, it allows for precise control of the degree of branching (deviation ±0.05), ensuring stable batch performance.

[0061] Preferably, the catalyst in step (1) accounts for 30%-40% of the total catalyst, for example, it can be 32%, 33%, 35%, 36% or 38%, etc.

[0062] Preferably, the end-capping agent in step (3) accounts for 5%-15% of the total end-capping agent, for example, it can be 6%, 8%, 10%, 12% or 14%, etc.

[0063] Preferably, the second capping reaction stops after the -NCO group has reacted completely.

[0064] Preferably, the content of -NCO groups in the hyperbranched polyurethane acrylate is less than 0.1%, for example, it can be 0%, 0.02%, 0.04%, 0.06% or 0.08%, etc.

[0065] Preferably, the preparation methods of the first, second, and third hyperbranched polyurethane acrylates each independently include the following steps:

[0066] (1) Mix a portion of the solvent with the multifunctional monomer and add it dropwise at 45-50℃ (e.g., 46℃, 47℃, 47.5℃, 48℃ or 49℃, etc.) and 200-300 r / min (e.g., 220 r / min, 240 r / min, 250 r / min, 260 r / min or 280 r / min, etc.) at a rate of 1-2 drops / second to the mixture of diisocyanate, the remaining solvent and part of the catalyst. After titration for 30-60 min (e.g., 35 min, 40 min, 45 min, 50 min or 55 min, etc.), carry out a prepolymerization reaction at 50-65℃ (e.g., 53℃, 55℃, 58℃, 60℃ or 63℃, etc.) for 2.5-3.5 h (e.g., 2.6 h, 2.8 h, 3 h, 3.2 h or 3.4 h, etc.) to obtain a hyperbranched prepolymer.

[0067] (2) Cool to 45-50℃ (e.g., 46℃, 47℃, 47.5℃, 48℃, or 49℃, etc.), add the remaining catalyst to the hyperbranched prepolymer at 200-300 r / min (e.g., 220 r / min, 240 r / min, 250 r / min, 260 r / min, or 280 r / min, etc.) and stir for 10-15 min (e.g., 11 min, 12 min, 12.5 min, 13 min, or 14 min, etc.), then add the pre-dehydrated polyol, raise the temperature to 60-70℃ (e.g., 62℃, 64℃, 65℃, 66℃, or 68℃, etc.), and carry out the polymerization reaction at 300-400 r / min (e.g., 320 r / min, 340 r / min, 350 r / min, 360 r / min, or 380 r / min, etc.) for 2.5-3.5 h (e.g., 2.6 h). (e.g., 2.8 h, 3 h, 3.2 h, or 3.4 h) to obtain hyperbranched polymers;

[0068] (3) A mixture of the polymerization inhibitor and a portion of the end-capping agent is added to the hyperbranched polymer at 40-60℃ (e.g., 45℃, 48℃, 50℃, 53℃, or 55℃, etc.) and 100-400 r / min (e.g., 150 r / min, 200 r / min, 250 r / min, 300 r / min, or 350 r / min, etc.) for the first end-capping reaction, with a reaction time of 0.5-1 h (e.g., 0.6 h, 0.7 h, 0.75 h, 0.8 h, or 0.9 h, etc.). Subsequently, the remaining end-capping agent is added dropwise at the same temperature for 0.5-1.5 h (e.g., 0.6 h, 0.8 h, 1 h, 1.2 h, or 1.4 h, etc.), and the temperature is increased to 60-70℃ (e.g., 62℃, 64℃, 65℃, 66℃, or 68℃, etc.) and the reaction is carried out at 300-400 r / min (e.g., 320 r / min, etc.). The second end-capping reaction is continued for 2-4 h (e.g., 2.5 h, 2.8 h, 3 h, 3.2 h, or 3.5 h) under conditions of 340 r / min, 350 r / min, 360 r / min, or 380 r / min, etc.), followed by distillation to remove the solvent for 1-2 h (e.g., 1.2 h, 1.4 h, 1.5 h, 1.6 h, or 1.8 h) under conditions of 55-70℃ (e.g., 58℃, 60℃, 63℃, 65℃, or 68℃, etc.) and a vacuum degree of -0.085 to -0.095 MPa (e.g., -0.088 MPa, -0.089 MPa, -0.09 MPa, -0.092 MPa, or -0.093 MPa, etc.) to obtain the hyperbranched polyurethane acrylate.

[0069] Preferably, the multifunctional monomer includes any one or a combination of at least two of trimethylolpropane, pentaerythritol, or triethanolamine.

[0070] Preferably, the diisocyanate includes any one or a combination of at least two of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, or toluene diisocyanate.

[0071] Preferably, the polyol includes any one or a combination of at least two of polypropylene glycol, polytetrahydrofuran glycol, or polycaprolactone polyol.

[0072] Preferably, the catalyst comprises any one or a combination of at least two of dibutyltin dilaurate, stannous octoate, or potassium hydroxide.

[0073] Preferably, the capping agent comprises any one or a combination of at least two of hydroxyethyl acrylate, hydroxypropyl methacrylate, or glycidyl acrylate.

[0074] Preferably, the polymerization inhibitor comprises any one or a combination of at least two of hydroquinone, p-hydroxyanisole, p-phenol, p-benzoquinone, p-methoxyphenol, or 2,6-di-tert-butyl-p-cresol.

[0075] Preferably, the solvent includes any one or a combination of at least two of ethyl acetate, methyl ethyl ketone, or N,N-dimethylformamide.

[0076] Preferably, the viscosity of the photocurable elastomer at 25°C is ≤5000 mPa·s, for example, it can be 3000 mPa·s, 3500 mPa·s, 4000 mPa·s, 4500 mPa·s or 4700 mPa·s, etc.

[0077] Preferably, the elongation at break of the photocurable elastomer after curing is ≥100%, for example, it can be 120%, 150%, 200%, 250% or 300%, etc.

[0078] Preferably, the photocurable elastomer has a tensile strength ≥3.5 MPa after curing, for example, it can be 5 MPa, 10 MPa, 15 MPa, 20 MPa or 25 MPa, etc.

[0079] In a second aspect, the present invention provides a method for preparing a photocurable elastomer as described in the first aspect, the method comprising the following steps:

[0080] (1) Mix and stir the reactive diluent monomer, photoinitiator, and optional toughening agent, then add optional polymerization inhibitor, optional functional filler and optional curing agent and mix and stir, then add optional pigment paste and mix and stir to obtain a mixed liquid;

[0081] (2) The hyperbranched polyurethane acrylate composition and epoxy resin are mixed and stirred with the mixed liquid in step (1) to obtain the photocurable elastomer.

[0082] Preferably, the mixing temperature in step (2) is 40-60°C, for example, it can be 45°C, 48°C, 50°C, 53°C or 55°C.

[0083] Preferably, the mixing time in step (2) is 0.5-1.5 h, for example, it can be 0.6 h, 0.8 h, 1 h, 1.2 h or 1.4 h.

[0084] Preferably, the mixing speed in step (2) is 800-1400 r / min, for example, it can be 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min or 1300 r / min, etc.

[0085] Preferably, after mixing and stirring in step (2), a post-processing step is further included, and the post-processing method includes filtration through a sieve.

[0086] Preferably, the mesh size of the sieve is 80-120 mesh, for example, it can be 85 mesh, 90 mesh, 100 mesh, 110 mesh or 115 mesh, etc.

[0087] Preferably, the method for preparing the photocurable elastomer includes the following steps:

[0088] (1) Mix and stir the reactive diluent monomer, photoinitiator, and optional toughening agent at 20-30℃ (e.g., 22℃, 24℃, 25℃, 26℃ or 28℃, etc.) and 200-500 r / min (e.g., 250 r / min, 300 r / min, 350 r / min, 400 r / min or 450 r / min, etc.), then add optional polymerization inhibitor, optional functional filler and optional curing agent and mix and stir for 30-60 min (e.g., 35 min, 40 min, 45 min, 50 min or 55 min, etc.), then add optional pigment paste and mix and stir for 30-60 min (e.g., 35 min, 40 min, 45 min, 50 min or 55 min, etc.) to obtain a mixed liquid;

[0089] (2) The hyperbranched polyurethane acrylate composition and epoxy resin are added to the mixed liquid in step (1) and stirred for 0.5-1.5 h (e.g., 42℃, 45℃, 50℃, 55℃ or 58℃) ​​at 40-60℃ (e.g., 42℃, 45℃, 50℃, 55℃ or 58℃) ​​and 800-1400 r / min (e.g., 900 r / min, 1000 r / min, 1100 r / min, 1200 r / min or 1300 r / min) to obtain the photocurable elastomer.

[0090] Thirdly, the present invention provides a cured product, which is prepared from the photocurable elastomer described in the first aspect.

[0091] Preferably, the method for preparing the cured product includes the following steps:

[0092] (1) The photocurable elastomer is subjected to photocuring treatment to obtain a primary photocurable product;

[0093] (2) The primary photocurable product is subjected to thermal curing treatment to obtain the cured product.

[0094] In this invention, a photothermal two-stage curing process is employed. Photocuring enables rapid interlayer bonding, while thermal curing promotes deep cross-linking between HPUA and epoxy, forming a dense network. This shortens the molding cycle and improves temperature resistance and mechanical retention.

[0095] Preferably, the wavelength of the light source for photocuring is 360-430 nm, for example, it can be 370 nm, 390 nm, 400 nm, 410 nm or 420 nm, etc.

[0096] Preferably, the light intensity for photocuring is 5000-8000 uw / cm². 2 For example, it could be 5500 uw / cm 2 6000 uw / cm 2 6500 uw / cm 2 7000 uw / cm 2 Or 7500 uw / cm 2 wait.

[0097] Preferably, the photocuring time is 2-15 s, for example, it can be 3 s, 6 s, 9 s, 10 s or 12 s.

[0098] Preferably, the thickness of the primary photocurable product is 1-3 mm, for example, it can be 1.5 mm, 1.8 mm, 2 mm, 2.3 mm or 2.5 mm, etc.

[0099] Preferably, the thermosetting includes primary thermosetting and secondary thermosetting.

[0100] Preferably, the temperature of the first heat curing is 75-85℃ (e.g., 76℃, 78℃, 80℃, 82℃ or 84℃, etc.), and the time is 0.5-1.5 h (e.g., 0.6 h, 0.8 h, 1 h, 1.2 h or 1.4 h, etc.).

[0101] Preferably, the temperature of the secondary heat curing is 105-115℃ (e.g., 106℃, 108℃, 110℃, 112℃ or 114℃, etc.), and the time is 7.5-8.5 h (e.g., 7.6 h, 7.8 h, 8 h, 8.2 h or 8.4 h, etc.).

[0102] Fourthly, the present invention provides an application of the photocurable elastomer as described in the first aspect in photocurable 3D printing.

[0103] Compared with the prior art, the present invention has at least the following beneficial effects:

[0104] By screening the raw materials for preparing photocurable elastomers, a photosensitive resin material with high printing accuracy, high elasticity (elongation at break ≥50%), high flexibility, and high tensile strength (≥8MPa) was obtained. Detailed Implementation

[0105] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0106] In the specific embodiments of the present invention, "parts" refers to "parts by mass".

[0107] Preparation Example 1

[0108] This preparation example provides a hyperbranched polyurethane acrylate, the preparation method of which includes the following steps:

[0109] 17.5 parts HDI, 5 parts ethyl acetate and 0.0003 parts DBTDL were added to a four-necked flask and stirred thoroughly at 200 r / min at room temperature to form a system; 4.2 parts TMP monomer were dissolved in 10 parts ethyl acetate and added to the system at a rate of 1-2 drops / second at 300 r / min under conditions of 50℃. The titration was completed in 60 min, and the temperature was raised to 65℃ and reacted at 300 r / min for 3 h to form a hyperbranched prepolymer.

[0110] The temperature was lowered to 50°C, and 0.0006 parts of DBTDL were added at 300 r / min and stirred for 10 min. Then, 43 parts of PPG2000 (purchased from Dow Chemical, brand name PPG-2000) and 30 parts of PTMG2000 (purchased from BASF, brand name PolyTHF 2000) that had been dehydrated beforehand were added. The temperature was raised to 70°C and reacted at 400 r / min for 3 h.

[0111] Dissolve 0.1 part of p-hydroxyanisole (MEHQ) in 1 part HEA and add it to the system at 60℃ and 400 r / min for 1 h. Then, add the remaining 4.2 parts of HEA dropwise to the prepolymer system over 1.5 h at the same temperature, maintain the temperature to 70℃, and continue the reaction at 400 r / min for 2-4 h. Detect the polymer infrared spectrum until no characteristic peak of -NCO functional groups (approximately 2270 cm⁻¹) is found. -1 Subsequently, the solvent was removed by vacuum distillation (-0.085~-0.095MPa) at 70℃ for 2 hours to obtain the hyperbranched polyurethane acrylate HPUA-1 with a branching degree of 0.69.

[0112] Preparation Example 2

[0113] This preparation example provides a hyperbranched polyurethane acrylate, the preparation method of which includes the following steps:

[0114] 15 parts HDI, 16 parts IPDI, 10 parts ethyl acetate and 0.0003 parts DBTDL were added to a four-necked flask and stirred thoroughly at 200 rpm at room temperature to form a system. 5 parts TMP monomer and 2 parts PER monomer were dissolved in 10 parts ethyl acetate and added to the system at a rate of 1-2 drops / second at 200 rpm under conditions of 45°C. The titration was completed in 30-60 minutes. The temperature was then raised to 50°C and reacted at 200 rpm for 3 hours to form a hyperbranched prepolymer.

[0115] Cool to 45℃, add 0.0006 parts of DBTDL at 200r / min and stir for 10min, then add 25 parts of pre-dehydrated PPG1000 and 20 parts of PCL1000 (purchased from BASF, brand name PD1-10), heat to 60℃ and react at 300r / min for 3h.

[0116] Dissolve 0.2 parts BHT in 1.67 parts HEA and add it to the system at 40℃ and 400 rpm for 0.5 h. Then, at the same temperature, add 8.33 parts HEA and 6.8 parts HPMA dropwise to the prepolymer system over 0.5 h, maintain the temperature to 60℃, and continue the reaction at 300 rpm for 2-4 hours. Detect the polymer infrared spectrum until no characteristic peak of -NCO functional groups (approximately 2270 cm⁻¹) is found. -1 Subsequently, the solvent was removed by vacuum distillation (-0.085~-0.095MPa) at 70℃ for 2 hours to obtain the hyperbranched polyurethane acrylate HPUA-2 with a branching degree of 0.81.

[0117] Preparation Example 3

[0118] 19.4 parts TDI, 27.95 parts HDI, 15 parts ethyl acetate and 0.0003 parts DBTDL were added to a four-necked flask and stirred thoroughly at 300 rpm at room temperature to form a system. 6 parts TMP monomer and 8 parts PER monomer were dissolved in 10 parts ethyl acetate and added to the system at a rate of 1-2 drops / second at 200 rpm under conditions of 45°C. The titration was completed in 60 min, and the temperature was raised to 50°C and reacted at 200 rpm for 3 h to form a hyperbranched prepolymer.

[0119] Cool down to 45℃, add 0.0006 parts of DBTDL at 200r / min and stir for 10min, then add 15 parts of pre-dehydrated PCL500 (purchased from Guangzhou Haoyi, brand name PCL205), heat up to 60℃ and react at 300r / min for 3h.

[0120] 2.36 parts of GMA were dissolved in 0.05 parts of BHT and added to the system at 40°C and 400 rpm for 0.5 h. Subsequently, 21.24 parts of GMA were added dropwise to the prepolymer system over 0.5 h at the same temperature, and the temperature was maintained at 60°C. The reaction was continued at 400 rpm for 2-4 h. The polymer infrared spectrum was measured until no characteristic peak of -NCO functional groups (approximately 2270 cm⁻¹) was observed. -1 Subsequently, the solvent was removed by vacuum distillation (-0.085~-0.095MPa) at 70℃ for 2 hours to obtain the hyperbranched polyurethane acrylate HPUA-3 with a branching degree of 0.9.

[0121] Preparation Example 4

[0122] This preparation example provides a linear polyurethane acrylate, the preparation method of which includes the following steps:

[0123] Weigh 60 parts of PPG2000 and dehydrate under vacuum (-0.1 MPa) at 115℃ for 1.5 h; when cooled to 55℃, add 0.001 parts of DBTDL, stir at 200 r / min for 20 min, and purge with nitrogen three times (10 min each time); then slowly add 21.67 parts of HDI while stirring at 200 r / min over the next 30 min. After the addition is complete, raise the temperature to 90℃ and react at 350 r / min for 3 h; cool to 60℃ and add a mixed solution of 0.04 parts of hydroquinone dissolved in 1.83 parts of HEA, stir for 30 min, then add 16.46 parts of HEA dropwise, and then raise the temperature to 65℃ and react at 350 r / min for 3 h. Infrared detection showed no 2270 cm⁻¹. -1 Characteristic peaks were observed to obtain the linear polyurethane acrylate.

[0124] Preparation Example 5

[0125] This preparation example provides a hyperbranched polyurethane acrylate, the preparation method of which includes the following steps:

[0126] 26.5 parts HDI, 5 parts ethyl acetate and 0.0003 parts DBTDL were added to a four-necked flask and stirred thoroughly at 200 rpm at room temperature to form a system; 4.8 parts TMP monomer were dissolved in 10 parts ethyl acetate and added to the system at 300 rpm at 50 °C at a rate of 1-2 drops / second. The titration was completed in 60 min, and the temperature was raised to 65 °C and reacted at 300 rpm for 3 h to form a hyperbranched prepolymer.

[0127] Cool down to 50℃, add 0.0006 parts of DBTDL at 300r / min and stir for 10min, then add 25 parts of PPG2000 and 24.7 parts of PTMG2000 that have been dehydrated beforehand, heat up to 70℃ and react at 400r / min for 3h.

[0128] 0.1 part MEHQ was dissolved in 1.89 parts HEA and added to the system at 60℃ and 400 r / min for 1 h. Subsequently, the remaining 17.01 parts HEA were added dropwise to the prepolymer system over 1.5 h at the same temperature, and the temperature was maintained at 70℃. The reaction was continued at 400 r / min for 2-4 h, and the polymer infrared spectrum was detected until no characteristic peak of -NCO functional groups (approximately 2270 cm⁻¹) was observed. The solvent was then removed by vacuum distillation (-0.085~-0.095 MPa) at 70℃ for 2 h to obtain the hyperbranched polyurethane acrylate HPUA-0.

[0129] Example 1

[0130] This embodiment provides a photocurable elastomer, the preparation method of which includes the following steps:

[0131] Weigh 1 part of Irgacure 2959 and dissolve it in a mixed solvent of 7.5 parts TPGDA, 7.5 parts EOTMPTA, 0.3 parts MX-154, and 0.05 parts 370 at 300 rpm. Then add 0.05 parts PHP, 3 parts graphene nanosheets, and 5.4 parts D230 and continue stirring for 60 min. Next, add 0.2 parts UK-9007 and continue stirring for 10 min. Finally, add 40 parts HPUA-1, 20 parts HPUA-2, 10 parts HPUA-3, and 5 parts TDE-85 and stir thoroughly at 1200 rpm for 1.5 h. Filter through a 100-mesh nylon filter (to remove possible impurity particles and avoid clogging during 3D printing) to obtain the photocurable elastomer.

[0132] The raw materials for preparing the photocurable elastomer in Example 1 are shown in Table 1.

[0133] Table 1

[0134]

[0135] Example 2

[0136] This embodiment provides a photocurable elastomer, the preparation method of which includes the following steps:

[0137] Weigh 1 part of 2959 and 1 part of 184D, and dissolve them in a mixed solvent of 10 parts TPGDA, 8 parts EOTMPTA, 7 parts HDDA, 0.3 parts CTBN, 0.2 parts MX-154, 0.04 parts EFKA-3777, and 0.04 parts 370 at 300 r / min. Then add 0.1 parts BHT, 1 part multi-walled carbon nanotubes, and 5.92 parts EC301 and continue stirring for 60 min. Subsequently, add 0.4 parts UK-9007 and continue stirring for 10 min. Finally, add 32.92 parts HPUA-1, 15 parts HPUA-2, 11 parts HPUA-3, 6 parts DER438, and 4 parts AG-80 and stir thoroughly at 1200 r / min for 1.5 h. Filter through a 100-mesh nylon filter (to remove possible impurity particles and avoid clogging during 3D printing) to obtain the photocurable elastomer.

[0138] The raw materials for preparing the photocurable elastomer in Example 2 are shown in Table 2.

[0139] Table 2

[0140]

[0141] Example 3

[0142] This embodiment provides a photocurable elastomer, the preparation method of which includes the following steps:

[0143] Weigh 1 part of 2959 and 0.53 parts of 184D, and dissolve them in a mixed solvent of 10 parts TPGDA, 10 parts EOTMPTA, 0.2 parts CTBN, 0.2 parts MX-154, 0.04 parts EFKA-3777, and 0.02 parts 370 at 300 rpm. Then add 0.05 parts PHP, 0.02 parts BHT, 1 part graphene nanosheets, 2 parts multi-walled carbon nanotubes, and 5 parts polyamide 650 and continue stirring for 60 min. Then add 0.3 parts UK-9007 and continue stirring for 10 min. Finally, add 32.64 parts HPUA-1, 20 parts HPUA-2, 10 parts HPUA-3, 3 parts TDE-85, 3 parts AG-80, and 1 part DER 438 and stir thoroughly at 1200 rpm for 1.5 h. The photocurable elastomer was obtained by filtering with a 100-mesh nylon filter (to remove possible impurity particles and avoid clogging during 3D printing).

[0144] The raw materials for preparing the photocurable elastomer in Example 3 are shown in Table 3.

[0145] Table 3

[0146]

[0147] Example 4

[0148] This embodiment provides a photocurable elastomer, the preparation method of which includes the following steps:

[0149] Weigh out 1 part 2959 and 1 part 184D, and dissolve them in a mixed solvent of 10 parts TPGDA, 9 parts EOTMPTA, 0.2 parts CTBN, 0.3 parts MX-154, 0.04 parts EFKA-3777, and 0.03 parts 370 at 300 rpm. Then add 0.05 parts PHP, 0.03 parts BHT, 1 part graphene nanosheets, 1 part multi-walled carbon nanotubes, 5 parts polyamide 650, and 3 parts Evonik 2910 and continue stirring for 60 min. Then add 0.4 parts UK-9007 and continue stirring for 10 min. Finally, add 27.95 parts HPUA-1, 20 parts HPUA-2, 10 parts HPUA-3, 5 parts TDE-85, 3 parts AG-80, and 2 parts DER 438 and stir thoroughly at 1200 rpm for 1.5 h. The photocurable elastomer was obtained by filtering with a 100-mesh nylon filter (to remove possible impurity particles and avoid clogging during 3D printing).

[0150] The raw materials for preparing the photocurable elastomer in Example 4 are shown in Table 4.

[0151] Table 4

[0152]

[0153] Comparative Example 1

[0154] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that 40 parts of HPUA-1, 20 parts of HPUA-2, and 10 parts of HPUA-3 in Example 1 are replaced with 70 parts of HPUA-1, and all other steps are the same as in Example 1.

[0155] Comparative Example 2

[0156] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that 40 parts of HPUA-1, 20 parts of HPUA-2, and 10 parts of HPUA-3 in Example 1 are replaced with 70 parts of HPUA-2, and all other steps are the same as in Example 1.

[0157] Comparative Example 3

[0158] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that 40 parts of HPUA-1, 20 parts of HPUA-2, and 10 parts of HPUA-3 in Example 1 are replaced with 70 parts of HPUA-3, and all other steps are the same as in Example 1.

[0159] Comparative Example 4

[0160] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that 40 parts of HPUA-1, 20 parts of HPUA-2, and 10 parts of HPUA-3 in Example 1 are replaced with 35 parts of HPUA-1 and 35 parts of HPUA-3. All other steps are the same as in Example 1.

[0161] Comparative Example 5

[0162] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that 40 parts of HPUA-1, 20 parts of HPUA-2, and 10 parts of HPUA-3 in Example 1 are replaced with 70 parts of linear polyurethane acrylate (from Preparation Example 4). All other steps are the same as in Example 1.

[0163] Comparative Example 6

[0164] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that TDE-85 is removed from Example 1, while all other steps are the same as in Example 1.

[0165] Comparative Example 7

[0166] This comparative example provides a photocurable elastomer, which differs from Example 1 only in that 40 parts of HPUA-1 in Example 1 are replaced with 40 parts of HPUA-0, and all other steps are the same as in Example 1.

[0167] Application Example 1-4, Comparative Application Example 1-7

[0168] Each of the following methods for using a photocurable elastomer is provided, the method comprising the following steps:

[0169] (1) The photocurable elastomer is subjected to photocuring treatment to obtain a primary photocurable product;

[0170] The wavelength of the light source is 360-430 nm, and the illuminance is 5000-8000 uw / cm². 2 The curing time for each photocuring cycle is 2-15 seconds; the thickness of the photocured product after each photocuring cycle is 1-3 mm.

[0171] (2) Clean the primary photocurable product with isopropanol, and then heat-cur the product using a heat curing process of 80℃×1h+110℃×8h to obtain the final printed model.

[0172] Test methods

[0173] The following tests were performed on the final printed models corresponding to use cases 1-4 and comparative application examples 1-7.

[0174] Elongation at break: Tested according to GB / T 528-2009.

[0175] Tensile strength: Tested according to GB / T 528-2009.

[0176] Tear strength: Tested according to GB / T 529-2008.

[0177] Elastic recovery rate: Tested according to GB / T 1681-2011.

[0178] Initial viscosity at 25°C: tested using MCR102e Anton Paar.

[0179] Viscosity after standing for 8 hours: same as above.

[0180] Solvent resistance (mass change rate % after 24h immersion in acetone): Tested according to GB / T 1690-2010.

[0181] Tear strength retention rate after heat aging (80℃×100h, %): Tested according to GB / T 3512-2014.

[0182] The test results are shown in Table 5.

[0183] Table 5

[0184]

[0185] The final printed models obtained from corresponding use cases 1-4 can be verified by Fourier transform infrared spectroscopy (FTIR): after HPUA is mixed with epoxy resin, the peak intensity of urethane bond (characteristic peak at approximately 3300 cm⁻¹) decreases and the peak intensity of epoxy group (characteristic peak at approximately 910 cm⁻¹) decreases, proving that the two form an interpenetrating network through hydrogen bonds, rather than a simple physical mixture; this interpenetrating network can reduce interfacial tension and avoid phase separation.

[0186] The percentage reduction in characteristic peak intensity of the printed models in Application Examples 1-4 is shown in Table 2. Characteristic peak intensity reduction percentage = (peak intensity of the photocurable elastomer before curing - peak intensity of the final printed model after curing) / peak intensity of the photocurable elastomer before curing.

[0187] Table 2

[0188]

[0189] The test results show that:

[0190] (1) As can be seen from Examples 1-4, the present invention uses polyurethane acrylate oligomers with branching degree gradients and epoxy resins to ensure elasticity. The low-branched long-chain polyols ensure elasticity, the high-branched multifunctional monomers enhance strength, and the epoxy optimizes compatibility and viscosity stability. It presents "multi-dimensional synergistic advantages" in core performance, with an elongation at break of 150%-320%, tensile strength of 12.5-18.3 MPa, and tear strength of 7.2-9.1 kN / m. At the same time, the initial viscosity at 25℃ is 2850-3350 mPa・s, the viscosity change rate after standing for 8 hours is only 5.9%-21.8%, the solvent resistance (mass change rate after 24 hours of acetone immersion) is 1.0%-1.8%, and the tear strength retention rate after heat aging is 88%-94%, which fully matches the technical goal of "high elasticity, high strength, low viscosity suitable for 3D printing, and high storage stability".

[0191] (2) By comparing Example 1 with Comparative Examples 1-3, it can be seen that Comparative Examples 1-3 (single HPUA) either lack highly branched rigid units (the tensile strength of Comparative Example 1 is only 8.2 MPa) or lacks low-branched flexible units (the elongation at break of Comparative Example 3 is only 85%), and thus cannot balance elasticity and strength.

[0192] A comparison of Examples 1 and Examples 5-7 shows that Comparative Example 5 (linear PUA), lacking a hyperbranched structure, has an initial viscosity of 4800 mPa·s and a viscosity of 8250 mPa·s after standing, with a solvent resistance of 8.6%, making it completely unsuitable for printing and practical use. Comparative Example 6 (without epoxy synergy) and Comparative Example 7 (low-branched HPUA-0), due to the lack of epoxy compatibility optimization or a branching degree deviating from the 0.6-1.0 range, have low tensile strength (9.3 MPa and 6.9 MPa, respectively) and high viscosity change rate (13.9% and 10.6%, respectively), with overall performance far inferior to Examples 1-4.

[0193] In summary, by screening the raw materials for preparing photocurable elastomers, this invention has obtained a photosensitive resin material with high printing accuracy, high elasticity (elongation at break ≥50%), high flexibility, and high tensile strength (≥8MPa).

[0194] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A photocurable elastomer, characterized in that, The raw materials for preparing the photocurable elastomer include the following components: hyperbranched polyurethane acrylate composition, epoxy resin, reactive diluent monomer, and photoinitiator; The hyperbranched polyurethane acrylate composition comprises a first hyperbranched polyurethane acrylate, a second hyperbranched polyurethane acrylate, and a third hyperbranched polyurethane acrylate. The degree of branching of the first hyperbranched polyurethane acrylate is 0.6-0.7, the degree of branching of the second hyperbranched polyurethane acrylate is 0.8-0.89, and the degree of branching of the third hyperbranched polyurethane acrylate is 0.9-1.

0.

2. The photocurable elastomer according to claim 1, characterized in that, The hyperbranched polyurethane acrylate composition comprises the following components in parts by weight: 3-4 parts of first hyperbranched polyurethane acrylate, 1-2 parts of second hyperbranched polyurethane acrylate, and 1 part of third hyperbranched polyurethane acrylate.

3. The photocurable elastomer according to claim 1 or 2, characterized in that, The epoxy resin includes glycidylamine type epoxy resin and / or bisphenol F type epoxy resin; Preferably, the reactive diluent monomer comprises any one or a combination of at least two of tripropylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, or 1,6-hexanediol diacrylate. Preferably, the photoinitiator includes Irgacure 2959 and / or Irgacure 184D.

4. The photocurable elastomer according to any one of claims 1-3, characterized in that, The raw materials for preparing the photocurable elastomer include the following components in parts by weight: 55-70 parts of hyperbranched polyurethane acrylate composition, 5-10 parts of epoxy resin, 15-25 parts of reactive diluent monomer, and 1-2 parts of photoinitiator.

5. The photocurable elastomer according to any one of claims 1-4, characterized in that, The raw materials for preparing the photocurable elastomer also include toughening agents; Preferably, the toughening agent comprises a core-shell structured acrylate toughening agent and / or a carboxyl-terminated liquid nitrile rubber; Preferably, the toughening agent is present in 0.3-0.5 parts by weight; Preferably, the raw materials for preparing the photocurable elastomer further include a leveling agent; Preferably, the leveling agent is present in a weight fraction of 0.05-0.08 parts. Preferably, the raw materials for preparing the photocurable elastomer further include pigment paste; Preferably, the pigment paste has a weight ratio of 0.2-0.4 parts; Preferably, the raw materials for preparing the photocurable elastomer further include a polymerization inhibitor; Preferably, the polymerization inhibitor comprises p-hydroxyacetophenone and / or 2,6-di-tert-butyl-p-cresol; Preferably, the polymerization inhibitor is present in 0.05-0.1 parts by weight. Preferably, the raw materials for preparing the photocurable elastomer further include functional fillers; Preferably, the functional filler further includes graphene nanosheets and / or multi-walled carbon nanotubes; Preferably, the functional filler is present in 1-3 parts by weight; Preferably, the raw materials for preparing the photocurable elastomer further include a curing agent; Preferably, the curing agent is present in 5-8 parts by weight.

6. The photocurable elastomer according to any one of claims 1-5, characterized in that, The raw materials for preparing the first hyperbranched polyurethane acrylate each independently include the following components in parts by weight: 4.2-14 parts of multifunctional monomer, 17.5-47.35 parts of diisocyanate, 15-73 parts of polyol, 0.0001-0.001 parts of catalyst, 5.2-23.6 parts of end-capping agent, 0.05-0.2 parts of polymerization inhibitor, and 15-25 parts of solvent; The multifunctional monomers in the raw materials for preparing the first polyurethane acrylate include trimethylolpropane, and the polyols include polypropylene glycol and / or polytetrahydrofuran glycol. Preferably, the number average molecular weight of the polyol in the raw material for preparing the first polyurethane acrylate is 1800-2200 g / mol. Preferably, the raw materials for preparing the second hyperbranched polyurethane acrylate each independently comprise the following components in parts by weight: 4.2-14 parts of multifunctional monomer, 17.5-47.35 parts of diisocyanate, 15-73 parts of polyol, 0.0001-0.001 parts of catalyst, 5.2-23.6 parts of end-capping agent, 0.05-0.2 parts of polymerization inhibitor, and 15-25 parts of solvent; The polyfunctional monomers in the raw materials for preparing the second polyurethane acrylate include pentaerythritol and trimethylolpropane, and the polyols include polypropylene glycol and / or polycaprolactone. Preferably, the mass ratio of pentaerythritol to trimethylolpropane is 1:(2-3); Preferably, the number average molecular weight of the polyol in the raw materials for preparing the second polyurethane acrylate is 800-1200 g / mol; Preferably, the raw materials for preparing the third hyperbranched polyurethane acrylate each independently comprise the following components in parts by weight: 4.2-14 parts of multifunctional monomer, 17.5-47.35 parts of diisocyanate, 15-73 parts of polyol, 0.0001-0.001 parts of catalyst, 5.2-23.6 parts of end-capping agent, 0.05-0.2 parts of polymerization inhibitor, and 15-25 parts of solvent; The polyfunctional monomers in the raw materials for preparing the third polyurethane acrylate include pentaerythritol and trimethylolpropane, and the polyols in the raw materials for preparing the third polyurethane acrylate include polycaprolactone. Preferably, the mass ratio of pentaerythritol to trimethylolpropane is 1:(0.5-1); Preferably, the number average molecular weight of the polyol in the raw material for preparing the third polyurethane acrylate is 400-600 g / mol; Preferably, the preparation methods of the first, second, and third hyperbranched polyurethane acrylates each independently include the following steps: (1) Mix a portion of the solvent with a multifunctional monomer, and add the mixture dropwise to a mixture of diisocyanate, the remaining solvent and a portion of the catalyst to carry out a prepolymerization reaction to obtain a hyperbranched prepolymer; (2) The hyperbranched prepolymer is mixed with the remaining catalyst and polyol and subjected to polymerization to obtain the hyperbranched polymer; (3) The hyperbranched polymer is mixed with a mixture of a polymerization inhibitor and a portion of the end-capping agent to carry out the first end-capping reaction, and then the remaining end-capping agent is added dropwise to carry out the second end-capping reaction to obtain the hyperbranched polyurethane acrylate.

7. The photocurable elastomer according to claim 6, characterized in that, The multifunctional monomer includes any one or a combination of at least two of trimethylolpropane, pentaerythritol, or triethanolamine; Preferably, the diisocyanate includes any one or a combination of at least two of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, or toluene diisocyanate; Preferably, the polyol includes any one or a combination of at least two of polypropylene glycol, polytetrahydrofuran glycol, or polycaprolactone polyol; Preferably, the catalyst comprises any one or a combination of at least two of dibutyltin dilaurate, stannous octoate, or potassium hydroxide; Preferably, the capping agent comprises any one or a combination of at least two of hydroxyethyl acrylate, hydroxypropyl methacrylate, or glycidyl acrylate; Preferably, the polymerization inhibitor comprises any one or a combination of at least two of hydroquinone, p-hydroxyanisole, p-phenol, p-benzoquinone, p-methoxyphenol, or 2,6-di-tert-butyl-p-cresol; Preferably, the solvent includes any one or a combination of at least two of ethyl acetate, methyl ethyl ketone, or N,N-dimethylformamide.

8. A method for preparing a photocurable elastomer as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: (1) Mix and stir the reactive diluent monomer, photoinitiator, and optional toughening agent, then add optional polymerization inhibitor, optional functional filler and optional curing agent and mix and stir, then add optional pigment paste and mix and stir to obtain a mixed liquid; (2) The hyperbranched polyurethane acrylate composition and epoxy resin are mixed and stirred with the mixed liquid in step (1) to obtain the photocurable elastomer; Preferably, the mixing temperature in step (2) is 40-60℃; Preferably, the mixing and stirring time in step (2) is 0.5-1.5 h; Preferably, the mixing speed in step (2) is 800-1400 r / min.

9. A cured product, characterized in that, The cured product is prepared from the photocurable elastomer as described in any one of claims 1-7. Preferably, the method for preparing the cured product includes the following steps: (1) The photocurable elastomer is subjected to photocuring treatment to obtain a primary photocurable product; (2) The primary photocurable product is subjected to thermal curing treatment to obtain the cured product; Preferably, the wavelength of the light source for photocuring is 360-430 nm; Preferably, the light intensity for photocuring is 5000-8000 uw / cm². 2 ; Preferably, the photocuring time is 2-15 s; Preferably, the thickness of the primary photocurable product is 1-3 mm; Preferably, the thermosetting includes primary thermosetting and secondary thermosetting; Preferably, the temperature for the first heat curing is 75-85℃, and the time is 0.5-1.5 h; Preferably, the secondary thermosetting temperature is 105-115℃ and the time is 7.5-8.5 h.

10. The application of a photocurable elastomer as described in any one of claims 1-7 in photocurable 3D printing.

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