A photocured elastomer paste, its preparation method and use

Abstract

The application belongs to the technical field of light-cured resin, and particularly relates to a light-cured elastomer slurry, a preparation method and application thereof. The light-cured elastomer slurry is prepared from thermoplastic elastomer powder, active diluent, crosslinking agent, photoinitiator and swelling agent. The mass ratio of the active diluent to the thermoplastic elastomer powder is 1:0.1-0.5, and the molar amounts of the crosslinking agent, the photoinitiator and the swelling agent are 0.1-1%, 0.1-1% and 1%-5% of the molar amount of the active diluent, respectively. The resin type of the light-cured elastomer slurry is not limited by the modification method, the preparation is simple and easy to implement and green and environment-friendly, and the obtained light-cured 3D printing sample has good strength and toughness.

Description

Technical Field

[0001] This invention belongs to the field of photocurable resin technology, specifically relating to a photocurable elastomer slurry, its preparation method, and its application. Background Technology

[0002] Additive manufacturing is a technology that uses digital model files and specific materials to construct objects layer by layer through printing. It can be used to manufacture parts with complex shapes. Among the many 3D printing methods, photopolymerization is a key development direction for 3D printing technology due to its fast speed, high printing accuracy, and good product surface quality and performance. This method often uses photosensitive resins containing oligomers, reactive diluents, photoinitiators, and additives to print devices. Before printing, a model is prepared using a computer. Then, the photosensitive resin is selectively irradiated with ultraviolet or visible light, and three-dimensional solids are generated through layer-by-layer printing and stacking. There are various types of photopolymerization 3D printing technologies. Currently, the most widely used ones include stereolithography (SLA), digital light processing (DLP), continuous liquid surface manufacturing (CLIP), multi-nozzle printing (MJP), two-photon 3D printing (TPP or 2PP), and selective area transparent curing (LCD). Among these, stereolithography (SLA) and digital light processing (DLP) are the most widely used. SLA (Single Layer Laser) uses a UV spot to scan photosensitive resin, shaping it into a 3D object. Before curing, a suitable amount of liquid photosensitive resin is filled into a resin tank. A movable stage is positioned below the liquid surface, and the layer thickness is controlled by a computer. The laser spot then scans the liquid surface point by point along a pre-programmed path, creating a 2D cross-section. The liquid resin in the exposed area quickly solidifies, and the curing platform descends by the thickness of a single printing layer. The next cross-section is then scanned and cured, and this process is repeated until layers are stacked to form the entire 3D object. DLP (Digital Laser Prototyping) uses surface scanning for rapid prototyping. Under the control of specific wavelengths of UV or visible light and graphics, thin layers of resin of a certain thickness and shape are cured through a window at the bottom of the resin tank using surface scanning. After each resin curing, the curing platform moves up or down by the thickness of a layer, continuously repeating the scanning and curing steps to print the device layer by layer.

[0003] Photosensitive resins are typically composed of oligomers with active functional groups, reactive diluents, photoinitiators, and additives. Photocuring technology is an environmentally friendly technology that involves adding a photoinitiator to a liquid prepolymer and initiating a polymerization reaction of the unsaturated components in the system under ultraviolet light irradiation, thereby transforming it into a solid cross-linked polymer with a three-dimensional network structure. Existing photocurable resins include polyurethane acrylates, polyester acrylates, epoxy acrylates, polyether acrylates, pure acrylic resins, and vinyl resins. Among them, polyurethane acrylates are currently the most common and widely used photocurable resin. For example, Chinese invention patent application CN117264166A discloses various photocurable polyurethane acrylate resins and their preparation methods; Chinese invention patent CN118344532B discloses a photosensitive resin composition comprising multifunctional polyurethane acrylates and aliphatic urethane dimethacrylates, which can be used to prepare dental models with high strength, hardness, and toughness through 3D printing technology; Chinese invention patent application CN118667094A discloses a double-curable polyurethane acrylate photosensitive resin containing sterically hindered urea bonds, its preparation method, and its applications, which can be used in sink-type SLA and pull-type DLP, LCD, and other photocurable 3D printing technologies. However, the photocurable resins used in the above patents are all obtained by double bond modification. The preparation conditions of acrylate prepolymers are harsh and the process is complicated, and there are few types of resins available.

[0004] Another Chinese patent application, CN118108502A, discloses a method for preparing a zirconia photocurable ceramic slurry, including pre-preparation of the liquid phase, solid-liquid phase mixing, and optimization of the ceramic particle size ratio to improve the rheological properties and stability of the slurry. The preparation process is as follows: Zirconia powders with average particle sizes of 1 μm and 0.1 μm are mixed at a mass ratio of 3:1 according to the optimized ratio to prepare a solid phase. The resin monomer and photoinitiator are then uniformly mixed under constant temperature using magnetic stirring to prepare a liquid phase. Finally, the solid phase, liquid phase, and dispersant are ball-milled to a solid phase content of 60 wt%, resulting in a zirconia photocurable ceramic slurry with good rheological properties and stability. However, the acrylate photosensitive resin monomers used in this patent still require harsh double bond modification to obtain, and the liquid phase molecules and solid phase in this patent do not have the conditions for bonding. Zirconia particles cannot dissolve, swell, or form intermolecular bonding forces with the resin monomers. The liquid phase and solid phase are two isolated systems. Therefore, the prepared photocurable ceramic slurry is not homogeneous, but an unstable system that is very easy to separate, has difficult-to-control flowability, and has uneven density. Summary of the Invention

[0005] To address the shortcomings of existing methods, this invention provides a photocurable elastomer slurry, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A photocurable elastomer slurry is prepared from thermoplastic elastomer powder, reactive diluent, crosslinking agent, photoinitiator, and swelling agent.

[0008] Preferably, the mass ratio of the reactive diluent to the thermoplastic elastomer powder is 1:0.1-0.5, and the molar amounts of the crosslinking agent, photoinitiator, and swelling agent are 0.1%-1%, 0.1%-1%, and 1%-5% of the molar amount of the reactive diluent, respectively.

[0009] Preferably, the thermoplastic elastomer powder is formed by cryogenic pulverization of a thermoplastic elastomer, wherein the thermoplastic elastomer is one or more of thermoplastic polyamide elastomer (TPAE), thermoplastic polyurethane elastomer (TPU), thermoplastic polyester elastomer (TPEE), styrene-butadiene-styrene triblock copolymer (SBS), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-isoprene-styrene triblock copolymer (SIS), and polyolefin elastomer (POE).

[0010] Preferably, the reactive diluent is one or more of methyl acrylate (MA), methyl methacrylate (MMA), butyl acrylate (BA), isobornyl acrylate (IBOA), tripropylene glycol diacrylate (TPGDA), acrylamide (AAm), hydroxyethyl acrylate (HEA), dipropylene glycol diacrylate (DPGDA), pentaerythritol tetraacrylate (PETA), and trimethylolpropane triacrylate (TMPTMA).

[0011] Preferably, the crosslinking agent is one or more of polyethylene glycol diacrylate monomer (PEGDA), N,N'-methylenebisacrylamide (BIS), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPTMA), ethoxylated trimethylolpropane triacrylate (TMP(EO)nTA), 3(propoxy)propanetriol triacrylate (GPTA), di(trimethylolpropane)tetraacrylate (DTMPTA), pentaerythritol tetraacrylate (PETA), 4(ethoxy)pentaerythritol tetraacrylate (PE(EO)4TTA), and dipentaerythritol hexaacrylate (DPHA).

[0012] Preferably, the photoinitiator is one or more of the following: free radical photoinitiators: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone (2959), 2-hydroxy-2-methyl-1-phenylacetone (1173), 1-hydroxycyclohexylphenyl ketone (184), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), blue light initiator: phenyl-2,4,6-trimethylbenzoyl lithium phosphite (LAP), visible light initiator: fluorinated diphenyltitanium (784), and bis(pentafluorophenyl)titanium.

[0013] Preferably, the swelling agent is acrylic acid (AA) and / or methacrylic acid (MAA).

[0014] A method for preparing a photocurable elastomer slurry includes the following steps:

[0015] S1. The thermoplastic elastomer is cryogenically pulverized and sieved to obtain thermoplastic elastomer powder;

[0016] S2. Disperse the thermoplastic elastomer powder in an active diluent and a swelling agent and allow it to swell for a certain period of time to obtain a premixed solution;

[0017] S3. Add photoinitiator and crosslinking agent to the premixed liquid, mix evenly, and obtain photocurable elastomer slurry.

[0018] Preferably, the elastomer powder has a particle size ≤ 500 μm.

[0019] Application of a photocurable elastomer slurry in photocurable 3D printing.

[0020] Preferably, the application includes: printing a photocurable elastomer slurry into a preliminary fixed shape on a 3D printing device, followed by post-curing under ultraviolet light or visible light to obtain a printed sample.

[0021] The positive and beneficial effects of this invention are as follows:

[0022] 1. This invention utilizes thermoplastic elastomer powder to prepare photocurable 3D printing elastomer slurry, eliminating the need for chemical modification of oligomers, such as double bond modification, as required by existing technologies. The preparation process is simple, has no limitations on the type of elastomer, and provides a universal method for preparing photocurable resins. This invention selects a low-crystallinity polymer elastomer as the solid phase, and a solution of diluent, crosslinking agent, swelling agent, and photoinitiator as the liquid phase. Under the action of a highly polar swelling agent, small liquid molecules enter the spaces between elastomer molecular chains, resulting in a uniform and stable photocurable resin system through swelling. The active diluent, swelling agent, and crosslinking agent molecules all possess active groups. When the elastomer slurry is exposed to visible or ultraviolet light, under the action of the photoinitiator, the small liquid molecules entering the spaces between elastomer molecular chains undergo free radical polymerization, forming a semi-interpenetrating network structure with the elastomer. Simultaneously, the elastomer, distributed within the three-dimensional network of the photocurable polymer, acts as physical crosslinking points, resulting in a photocurable polymer with excellent mechanical properties.

[0023] 2. Existing technologies have a relatively limited range of resins suitable for photopolymer 3D printing. The flowability of photopolymer precursors is difficult to control, and the trade-off between printing speed and toughness in the final product restricts the development of photopolymer 3D printing. This invention broadens the range of photopolymer resins, freeing them from modification method limitations. Some polymers like TPAE, SEBS, and POE, which are difficult to modify with double bonds but possess excellent high strength and elasticity, can also be used to prepare photopolymer resins. Furthermore, the flowability of the photopolymer elastomer slurry and the performance of the photopolymer 3D printed product can be controlled by adjusting factors such as the type of diluent, elastomer type, solid content, elastomer molecular weight, crosslinking agent content, and swelling agent content in the slurry formulation. This overcomes the traditional trade-off between flowability and mechanical properties in photopolymer materials, providing a wider adjustment range. The preparation of the photopolymer elastomer slurry in this invention is simple, easy, and environmentally friendly. The resulting photopolymer printed samples exhibit good strength and toughness, showing significant application potential in high-end manufacturing and other fields. Attached Figure Description

[0024] Figure 1 This is a physical image of the photocurable elastomer slurry that can be used for 3D printing in Example 7.

[0025] Figure 2 This is the DLP photopolymerization 3D printed small airplane model in Example 1.

[0026] Figure 3 This is a physical image of the DLP photopolymer 3D printed elastomer template from Example 1.

[0027] Figure 4 The above are DSC curves of the one-time melt crystallization process of TPAE resin powders with molecular weights of 10000, 20000, and 30000 in Examples 1, 4, and 7.

[0028] Figure 5 The images show the DSC curves of the secondary melting of TPAE resin powders with molecular weights of 10000, 20000, and 30000 in Examples 1, 4, and 7.

[0029] Figure 6 The shear flow curves of the photocurable elastomer slurries prepared with TPAE resin powders of molecular weights of 30,000, 10,000, and 20,000 in Examples 7, 10, and 11 are shown.

[0030] Figure 7 The stress-strain curves are for the photopolymer 3D printed splines in Examples 7, 10, and 11.

[0031] Figure 8 The stress-strain curves are shown for the photopolymer 3D printed splines in Examples 1-9. Detailed Implementation

[0032] The present invention will be further described below with reference to some specific embodiments.

[0033] Example 1

[0034] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0035] S1. Use a cryogenic pulverizer to pulverize 10000 molecular weight TPAE resin to obtain TPAE powder. Use a 35 mesh sieve to finely sieve the TPAE powder to obtain TPAE powder with a particle size not exceeding 500μm.

[0036] S2. The TPAE powder from step S1 is swollen into the reactive diluent HEA. The mass ratio of the reactive diluent to the TPAE powder is 1:0.3. 1% of the swelling agent AA is added, the mixture is stirred evenly, and it is allowed to stand for 12 hours to obtain the TPAE premix.

[0037] S3. Add 0.1% of the crosslinking agent PEGDA and 0.1% of the photoinitiator TPO to the TPAE premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0038] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV light source DLP printer to obtain a pre-cured model, as well as dumbbell-shaped and strip-shaped polymer samples.

[0039] S5. The DLP printed sample from step S4 is post-cured under ultraviolet light for 3 hours to obtain the DLP photocurable 3D printed model and the elastomer sample.

[0040] Example 2

[0041] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0042] S1. TPU powder is obtained by crushing 10,000 molecular weight TPU resin with a cryogenic pulverizer. The TPU powder is then finely sieved with a 35-mesh sieve to obtain TPU powder with a particle size not exceeding 500μm.

[0043] S2. Prepare a compound diluent by mixing MMA and BA in a molar ratio of 1:1. Swell the TPU powder from step S1 into the compound diluent of MMA and BA. The mass ratio of the compound diluent to the TPU powder is 1:0.1. Add 3% of the swelling agent MAA, which accounts for 3% of the molar amount of the compound diluent. Stir evenly and let stand for 12 hours to obtain the TPU premixed solution.

[0044] S3. Add 0.5% of crosslinking agent BIS and 0.25% of photoinitiator TPO-L to the TPU premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0045] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on an ultraviolet laser SLA printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0046] S5. The SLA printed sample from step S4 is post-cured under ultraviolet light for 3 hours to obtain an SLA photocured 3D printed elastomer sample.

[0047] Example 3

[0048] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0049] S1. Use a cryogenic pulverizer to crush 10,000 molecular weight TPEE resin to obtain TPEE powder. Use a 35-mesh sieve to finely sieve the TPEE powder to obtain TPEE powder with a particle size not exceeding 500μm.

[0050] S2. Dissolve AAm in HEA to obtain a compound diluent with a HEA:AAm molar ratio of 4:1. Swell the TPEE powder from step S1 into the compound diluent of HEA and AAm with a mass ratio of compound diluent to TPEE powder of 1:0.5. Add 5% of the swelling agent AA according to the molar amount of the compound diluent, stir evenly, and let stand for 12 hours to obtain the TPEE premixed solution.

[0051] S3. Add 0.1% of crosslinking agent BIS and 0.5% of visible light initiator bis(pentafluorophenyl)titanium to the TPEE premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0052] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on a visible light source DLP printer to obtain a partially cured dumbbell-shaped polymer and a strip-shaped sample.

[0053] S5. The DLP printed sample from step S4 is post-cured under visible light for 3 hours to obtain a DLP photocurable 3D printed elastomer sample.

[0054] Example 4

[0055] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0056] S1. Use a cryogenic pulverizer to crush 20,000 molecular weight TPAE resin to obtain TPAE powder. Use a 35-mesh sieve to finely sieve the TPAE powder to obtain TPAE powder with a particle size not exceeding 500 μm.

[0057] S2. The TPAE powder from step S1 is swollen into the reactive diluent MA. The mass ratio of the reactive diluent to the TPAE powder is 1:0.3. 1% of the swelling agent AA is added, the mixture is stirred evenly, and it is allowed to stand for 12 hours to obtain the TPAE premix.

[0058] S3. Add 0.1% of the crosslinking agent TMPTMA and 0.1% of the photoinitiator 2959 to the TPAE premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0059] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV light source DLP printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0060] S5. The DLP printed sample from step S4 is post-cured under ultraviolet light for 3 hours to obtain a DLP photocurable 3D printed elastomer sample.

[0061] Example 5

[0062] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0063] S1. Use a cryogenic pulverizer to crush 20,000 molecular weight SBS resin to obtain SBS powder. Use a 35-mesh sieve to finely sieve the SBS powder to obtain SBS powder with a particle size not exceeding 500 μm.

[0064] S2. Prepare a compound diluent by mixing TPGDA and IBOA at a molar ratio of 2:1. Swell the SBS powder from step S1 into the compound diluent of TPGDA and IBOA. The mass ratio of the compound diluent to the SBS powder is 1:0.1. Add 3% of the swelling agent MAA, which accounts for 3% of the molar amount of the compound diluent. Stir evenly and let stand for 12 hours to obtain the SBS premixed solution.

[0065] S3. Add GPTA (0.5% of the molar amount of the compound diluent) and 1173 (0.25% of the molar amount of the compound diluent) to the SBS premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0066] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on an ultraviolet laser SLA printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0067] S5. The SLA printed sample from step S4 is post-cured under ultraviolet light for 3 hours to obtain an SLA photocured 3D printed elastomer sample.

[0068] Example 6

[0069] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0070] S1. SEBS resin with a molecular weight of 20,000 was crushed into SEBS powder using a cryogenic pulverizer. The SEBS powder was then finely sieved using a 35-mesh sieve to obtain SEBS powder with a particle size not exceeding 500 μm.

[0071] S2. Dissolve AAm in HEA to obtain a compound diluent with a HEA:AAm molar ratio of 4:1. Swell the SEBS powder from step S1 into the compound diluent of HEA and AAm with a mass ratio of compound diluent to SEBS powder of 1:0.5. Add 5% of the swelling agent AA according to the molar amount of the compound diluent, stir evenly, and let stand for 12 hours to obtain the SEBS premixed solution.

[0072] S3. Add 1% of the crosslinking agent DTMPTA and 0.5% of the visible light initiator 784 to the SEBS premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0073] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on a visible light source DLP printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0074] S5. The DLP printed sample from step S4 is post-cured under visible light for 3 hours to obtain a DLP photocurable 3D printed elastomer sample.

[0075] Example 7

[0076] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0077] S1. Use a cryogenic pulverizer to crush TPAE resin with a molecular weight of 30,000 to obtain TPAE powder. Use a 35-mesh sieve to finely sieve the TPAE powder to obtain TPAE powder with a particle size of no more than 500 μm.

[0078] S2. The TPAE powder from step S1 is swollen into the reactive diluent DPGDA. The mass ratio of the reactive diluent to the TPAE powder is 1:0.3. Add swelling agent AA accounting for 1% of the molar amount of DPGDA, stir evenly, and let stand for 12 hours to obtain the TPAE premixed solution.

[0079] S3. Add 0.1% of crosslinking agent PETA and 0.1% of photoinitiator 184 (based on the molar amount of DPGDA) to the TPAE premix obtained in step S2, stir until homogeneous, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0080] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV light source DLP printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0081] S5. The DLP printed sample from step S4 is post-cured under ultraviolet light for 3 hours to obtain a DLP photocurable 3D printed elastomer sample.

[0082] Example 8

[0083] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0084] S1. Use a cryogenic pulverizer to crush 30,000 molecular weight SIS resin to obtain SIS powder. Use a 35-mesh sieve to finely sieve the SIS powder to obtain SIS powder with a particle size not exceeding 500 μm.

[0085] S2. Prepare a compound diluent by mixing PETEA and TMPTA in a molar ratio of 3:1. Swell the SIS powder from step S1 into the compound diluent of PETEA and TMPTA. The mass ratio of the compound diluent to the SIS powder is 1:0.1. Add 3% of the swelling agent MAA according to the molar amount of the compound diluent, stir evenly, and let stand for 12 hours to obtain the SIS premixed solution.

[0086] S3. Add 0.5% of the crosslinking agent DPHA and 0.25% of the photoinitiator TPO to the SIS premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0087] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on an ultraviolet laser SLA printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0088] S5. The SLA printed sample from step S4 is post-cured under ultraviolet light for 3 hours to obtain an SLA photocured 3D printed elastomer sample.

[0089] Example 9

[0090] A method for preparing a photocurable elastomer slurry and its application in photocurable 3D printing includes the following steps:

[0091] S1. Use a cryogenic pulverizer to crush POE resin with a molecular weight of 30,000 to obtain POE powder. Use a 35-mesh sieve to finely sieve the POE powder to obtain POE powder with a particle size of no more than 500 μm.

[0092] S2. Dissolve AAm in HEA to obtain a compound diluent with a HEA:AAm molar ratio of 2:1. Swell the POE powder from step S1 into the compound diluent of HEA and AAm with a mass ratio of compound diluent to POE powder of 1:0.5. Add 5% of the swelling agent AA according to the molar amount of the compound diluent, stir evenly, and let stand for 12 hours to obtain POE premixed solution.

[0093] S3. Add 1.0% of crosslinking agent TMPTA and 0.5% of visible light initiator 784 to the POE premix obtained in step S2, stir evenly, and obtain a photocurable elastomer slurry that can be used for 3D printing.

[0094] S4. Print the photocurable elastomer slurry that can be used for 3D printing in step S3 on a visible light source DLP printer to obtain pre-cured dumbbell-shaped and strip-shaped polymer samples.

[0095] S5. The DLP printed sample from step S4 is post-cured under visible light for 3 hours to obtain a DLP photocurable 3D printed elastomer sample.

[0096] Example 10

[0097] The other conditions in this embodiment are the same as in embodiment 7, except that the molecular weight of the TPAE resin in this embodiment is 10000.

[0098] Example 11

[0099] The other conditions in this embodiment are the same as in embodiment 7, except that the molecular weight of the TPAE resin in this embodiment is 20,000.

[0100] Performance testing

[0101] Crystallinity test: The thermal properties of TPAE resin powders with molecular weights of 10,000, 20,000, and 30,000 in Examples 1, 4, and 7 were tested using a differential scanning calorimeter. The DSC curves of crystallization after one melt are shown below. Figure 4 As shown, the DSC curve of secondary melting is as follows: Figure 5 As shown, the crystallization temperatures of TPAE resins with molecular weights of 10000, 20000, and 30000 are 96.3℃, 97.1℃, and 83.3℃, ​​respectively, and their secondary melting points are 152℃, 149℃, and 131℃, respectively. TPAEs with the same structural type but different molecular weights have different crystallization temperatures and melting points.

[0102] Viscosity test: Figure 1 This is a photograph of the photocurable elastomer slurry prepared using 30,000 molecular weight TPAE resin powder in Example 7. The photocurable 30,000 molecular weight TPAE slurry is semi-transparent.

[0103] At room temperature, and with the entire test conducted in the dark, the shear rheology of the photocurable elastomer slurries in Examples 7, 10, and 11 was tested using a rotational rheometer. The results are as follows: Figure 6 As shown, the photosensitive resins prepared in Examples 7, 10, and 11 exhibit shear-thinning flow characteristics. Combined with crystallinity tests, it can be seen that in the same liquid-phase formulation, TPAE with higher crystallinity has more complete crystal regions and a more compact molecular chain segment arrangement. This makes it difficult for the swelling agent to penetrate between the chain segments and promote its swelling effect in the diluent. Therefore, TPAE with higher crystallinity has lower swelling degree and lower initial shear viscosity in the diluent, while TPAE with lower crystallinity has higher swelling degree and higher initial shear viscosity in the diluent.

[0104] Mechanical property testing: Figure 3These are actual images of dumbbell-shaped and strip-shaped polymer samples prepared by DLP photopolymerization 3D printing using 10,000 molecular weight TPAE resin powder in Example 1. The samples have smooth surfaces and exhibit a semi-transparent, slightly whitish appearance. Figure 2 The small airplane model obtained by DLP printing of 10,000 molecular weight TPAE resin powder in Example 1 has a smooth surface and high printing accuracy.

[0105] At room temperature, tensile tests were performed on the photocurable 3D printed polymer strips from Examples 1-11 using a universal testing machine. The stress-strain curves of the strips were obtained, and the results are as follows: Figure 7 , Figure 8 As shown.

[0106] from Figure 7 It can be seen that, under the same liquid phase composition, the mechanical properties of photocured specimens prepared with TPAE of different crystallinities also differ. Crystallinity affects the fluidity of the photocured TPAE slurry by influencing its swelling effect, thereby affecting the printing effect and the mechanical properties of the photocured specimens. Choosing TPAE with lower crystallinity results in better swelling, more uniform dispersion of TPAE particles in the liquid phase, and higher toughness of the photocured specimens. However, when the swelling is too high, the proportion of liquid phase in the system is too low, leading to TPAE particle aggregation, poor slurry fluidity, poor photocuring 3D printing effect, and uneven overall density of the photocured polymer, which can cause stress concentration and a decrease in elongation at break. Therefore, as the crystallinity of TPAE decreases, the swelling effect of TPAE increases, the fluidity of the photocured TPAE slurry decreases, and the toughness of the photocured 3D printed TPAE specimens first increases and then decreases.

[0107] from Figure 8 As can be seen, the photocured sample in Example 9 exhibits hard and brittle properties, with a fracture strength reaching approximately 30 MPa. The photocured samples in Examples 3, 4, 6, and 7 exhibit hard and tough properties, showing yielding during tensile testing. Example 4 demonstrates the best toughness, with a strength of 21 MPa and an elongation at break of 259%. The photocured samples in Examples 1, 2, 5, and 8 exhibit soft and tough properties, with a high elongation at break, reaching approximately 300%. This indicates that adjusting the type of diluent, elastomer type, elastomer molecular weight, swelling agent content, crosslinking agent content, and solid content of the photocured elastomer slurry can all alter the mechanical properties of photocured 3D printed polymer samples, resulting in photocured samples with different mechanical characteristics—soft and tough, hard and tough, or hard and brittle—thus endowing photocured 3D printed products with a wide range of adjustable mechanical properties.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A photocurable elastomer slurry, characterized in that, It is prepared from thermoplastic elastomer powder, reactive diluent, crosslinking agent, photoinitiator, and swelling agent; The thermoplastic elastomer powder is formed by cryogenic pulverization of a thermoplastic elastomer, wherein the thermoplastic elastomer is one or more of thermoplastic polyamide elastomer, thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, styrene-butadiene-styrene triblock copolymer, styrene-ethylene-butene-styrene block copolymer, styrene-isoprene-styrene triblock copolymer, and polyolefin elastomer; The thermoplastic elastomers are distributed in the three-dimensional network of the photocurable polymer and act as physical crosslinking points; The swelling agent is acrylic acid and / or methacrylic acid; The mass ratio of the reactive diluent to the thermoplastic elastomer powder is 1:0.1-0.5, and the molar amounts of the crosslinking agent, photoinitiator, and swelling agent are 0.1%-1%, 0.1%-1%, and 1%-5% of the molar amount of the reactive diluent, respectively. The active diluent is one or more of the following: methyl acrylate, methyl methacrylate, butyl acrylate, isobornyl acrylate, tripropylene glycol diacrylate, acrylamide, hydroxyethyl acrylate, dipropylene glycol diacrylate, pentaerythritol tetraacrylate, and trimethylolpropane triacrylate. The crosslinking agent is one or more of the following: polyethylene glycol diacrylate monomer, N,N'-methylenebisacrylamide, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, 3(propoxy)propanetriol triacrylate, di(trimethylolpropane)tetraacrylate, pentaerythritol tetraacrylate, 4(ethoxy)pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

2. The photocurable elastomer slurry according to claim 1, characterized in that, The photoinitiator is one or more of the following: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, 2-hydroxy-2-methyl-1-phenylacetone, 1-hydroxycyclohexylphenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, lithium phenyl-2,4,6-trimethylbenzoyl phosphite, diphenyltitanium fluoride, and bis(pentafluorophenyl)titanium fluoride.

3. A method for preparing the photocurable elastomer slurry according to claim 1 or 2, characterized in that, Includes the following steps: S1. The thermoplastic elastomer is cryogenically pulverized and sieved to obtain thermoplastic elastomer powder; S2. Disperse the thermoplastic elastomer powder in an active diluent and a swelling agent and allow it to swell for a certain period of time to obtain a premixed solution; S3. Add photoinitiator and crosslinking agent to the premixed liquid, mix evenly, and obtain photocurable elastomer slurry.

4. The application of the photocurable elastomer slurry according to claim 1 or 2 in photocurable 3D printing.

5. The application according to claim 4, characterized in that, The application includes: printing the photocurable elastomer slurry into a preliminary fixed shape on a 3D printing device, followed by post-curing under ultraviolet light or visible light to obtain a printed sample.

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