Photocuring elastomer slurry and preparation method and application thereof

Abstract

The invention belongs to the technical field of light-cured resin, and particularly relates to light-cured elastomer slurry as well as a preparation method and application thereof. The photocuring elastomer slurry is prepared from thermoplastic elastomer powder, a reactive diluent, a cross-linking agent, a photoinitiator and a swelling agent; the mass ratio of the reactive diluent to the thermoplastic elastomer powder is 1: (0.1-0.5), and the molar weight of the cross-linking agent, the molar weight of the photoinitiator and the molar weight of the swelling agent are respectively 0.1-1%, 0.1-1% and 1-5% of the molar weight of the reactive diluent. The resin type of the light-cured elastomer slurry is not limited by a modification method, the preparation is simple and easy to implement, green and environmentally friendly, and the obtained light-cured 3D printing sample has good strength and toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of photocurable resins, and in particular relates to a photocurable elastomer slurry and a preparation method and application thereof. Background Art

[0002] Additive manufacturing technology is a technology that uses digital model files and specific materials to construct objects by printing layer by layer. It can be used to manufacture parts with complex shapes. Among the many 3D printing methods, photocuring has fast speed, high printing accuracy, good product surface quality and performance. It is an important development direction of 3D printing technology. This molding method often uses photosensitive resin containing oligomers, active diluents, photoinitiators and additives to print devices. Before printing, the model is prepared by computer. Then the photosensitive resin is selectively irradiated with ultraviolet light or visible light, and three-dimensional entities are generated by printing and stacking layer by layer. There are various types of photocuring 3D printing technology. At present, the popular ones include stereolithography molding technology (SLA), digital light processing molding technology (DLP), continuous liquid surface manufacturing technology (CLIP), multi-nozzle printing molding technology (MJP), two-photon 3D printing technology (TPP or 2PP), and selective area light curing technology (LCD). Among them, stereolithography molding technology (SLA) and digital light processing molding technology (DLP) are the most widely used. SLA uses ultraviolet light spots to scan photosensitive resin to form it. Before curing, fill the resin tank with an appropriate amount of liquid photosensitive resin, and the lifting and moving stage is located below the liquid surface. The layer thickness height between the platform and the liquid surface is controlled by a computer. Then, the laser spot scans a 2D cross section point by point along the liquid surface according to the route pre-set by the computer program. The liquid resin in the exposure area quickly solidifies into a solid state, and the curing platform descends to the height of the single printing layer thickness, and then scans and solidifies the next layer of cross-section, and repeats this cycle until the layers are stacked to form the entire 3D entity. DLP uses surface scanning to perform rapid prototyping. Under the control of ultraviolet light or visible light of a specific wavelength and graphics, a thin layer of resin of a certain thickness and shape is cured by surface scanning through the window at the bottom of the resin tank. After each resin curing is completed, the curing platform moves up or down by a layer thickness, and the scanning and curing steps are repeated continuously to print the device layer by layer.

[0003] Photosensitive resins are usually composed of active functional group oligomers, active diluents, photoinitiators, and additives. Photocuring technology is an environmentally friendly technology that adds photoinitiators to liquid prepolymers to initiate polymerization of components containing unsaturated bonds in the system under ultraviolet light, thereby converting them into solid cross-linked polymers with a three-dimensional network structure. Existing photocurable resins include polyurethane acrylate, polyester acrylate, epoxy acrylate, polyether acrylate, pure acrylic resin, vinyl resin, etc., among which polyurethane acrylate is the most common and widely used photocurable resin. For example, Chinese invention patent application with publication number CN117264166A discloses a variety of photocurable polyurethane acrylate resins and preparation methods thereof; Chinese invention patent with publication number CN118344532B discloses a photosensitive resin composition including multifunctional polyurethane acrylate and aliphatic carbamate dimethacrylate, and the photosensitive resin can be used to prepare dental models with high strength, hardness and toughness through 3D printing technology; Chinese invention patent application with publication number CN118667094A discloses a dual-curable polyurethane acrylate photosensitive resin containing a large hindered urea bond and its preparation method and application, which can be used for sinking SLA and pull-up DLP, LCD and other photocurable 3D printing technologies. However, the photocurable resins used in the above patents are all obtained through double bond modification, the preparation conditions of acrylate prepolymers are harsh and the process is complicated, and the types of available resins are scarce.

[0004] In addition, the Chinese patent application with the publication number CN118108502A discloses a method for preparing a zirconium oxide photocurable ceramic slurry, including pre-preparation of a liquid phase, mixing of a solid phase and a liquid phase, and optimizing the ratio of the particle size of ceramic particles to improve the rheological properties and stability of the slurry. The preparation process is as follows: according to the optimized ratio, zirconium oxide powders with an average particle size of 1 μm and 0.1 μm are mixed in a mass ratio of 3:1 to prepare a solid phase for standby use, resin monomers and photoinitiators are mixed uniformly by magnetic stirring under a constant temperature environment to prepare a liquid phase, and the solid phase, liquid phase and dispersant are ball-milled and mixed according to a solid phase content of 60wt%, to obtain a zirconium oxide photocurable ceramic slurry with good rheological properties and stability. However, the acrylic photosensitive resin monomer used in this patent still needs to undergo double bond modification under harsh conditions to be obtained, and the liquid phase molecules and the solid phase in this patent do not have the conditions for combination. The zirconium oxide particles cannot dissolve, swell or form intermolecular binding forces with the resin monomer. The liquid phase and the solid phase are two isolated systems. Therefore, the prepared photocurable ceramic slurry is not homogeneous, but an unstable system that is extremely easy to stratify, difficult to control fluidity, and uneven density. Summary of the invention

[0005] In view of the shortcomings of the existing methods, the present invention provides a photocurable elastomer slurry and a preparation method and application thereof.

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

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

[0008] Preferably, 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, photoinitiator and swelling agent are 0.1%-1%, 0.1%-1% and 1%-5% of the molar amount of the active diluent, respectively.

[0009] Preferably, the thermoplastic elastomer powder is obtained by freeze-crushing a thermoplastic elastomer, and 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), poly(styrene-ethylene-butylene-styrene) elastomer (SEBS), polystyrene-polyisoprene-polystyrene 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), dipropylene glycol acrylamide (AAm), hydroxyethyl acrylate (HEA), diacrylate (DPGDA), pentaerythritol tetraacrylate (PETEA) and trimethylolpropane triacrylate (TMPTA).

[0011] Preferably, the cross-linking agent is one or more of polyethylene glycol diacrylate monomer (PEGDA), N,N'-methylenebisacrylamide (BIS), trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate (TMPT), ethoxylated trimethylolpropane triacrylate (TMP(EO)nTA), 3(propoxy)propylene triacrylate (GPTA), (trimethylolpropane) tetraacrylate (DTMPTTA), pentaerythritol tetraacrylate (PETTA), 4(ethoxy)pentaerythritol tetraacrylate (PE(EO)4TTA) and dipentaerythritol hexaacrylate (DPHA).

[0012] Preferably, the photoinitiator is one or more of the free radical photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (2959), 2-hydroxy-2-methyl-1-phenylpropiophenone (1173), 1-hydroxycyclohexyl phenyl ketone (184), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester (TPO-L), blue light initiator phenyl-2,4,6-trimethylbenzoyl lithium phosphite (LAP), visible light initiator fluorinated diphenyl titanocene (784) and bis(pentafluorophenyl) titanocene.

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

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

[0015] S1, freeze-crushing and sieving the thermoplastic elastomer to obtain thermoplastic elastomer powder;

[0016] S2, dispersing the thermoplastic elastomer powder in the active diluent and the swelling agent and swelling them for a certain period of time to obtain a premixed liquid;

[0017] S3. Add a photoinitiator and a cross-linking agent to the premixed liquid, mix them evenly, and obtain a photocurable elastomer slurry.

[0018] Preferably, the particle size of the elastomer powder is ≤500 μm.

[0019] The invention discloses an application of a photocurable elastomer slurry in photocurable 3D printing.

[0020] Preferably, the application includes: printing the photocurable elastomer slurry on a 3D printing device to initially fix the shape, and then post-curing it under ultraviolet light or visible light to obtain a printed sample.

[0021] The positive beneficial effects of the present invention are:

[0022] 1. The present invention uses thermoplastic elastomer powder to prepare photocurable 3D printing elastomer slurry. It is not necessary to chemically modify the oligomers such as double bond modification as in the prior art. The preparation process is simple and there is no restriction on the type of elastomer. A general method for preparing photocurable resin is provided. The present invention selects a high polymer elastomer with low crystallinity as the solid phase, and a diluent, a cross-linking agent, a swelling agent, and a photoinitiator solution as the liquid phase. Under the action of a strong polar swelling agent, small molecules in the liquid phase enter between the molecular chains of the elastomer, and the photocurable resin system is made uniform and stable through swelling. The active diluent, swelling agent, and cross-linking agent molecules all carry active groups. When the elastomer slurry is exposed to visible light or ultraviolet light, under the action of the photoinitiator, the small molecules in the liquid phase that enter between the molecular chains of the elastomer will undergo free radical polymerization reaction, forming a semi-network interpenetrating structure with the elastomer. At the same time, the elastomer is distributed in the three-dimensional network of the photocurable polymer and acts as a physical cross-linking point. The prepared photocurable polymer has excellent mechanical properties.

[0023] 2. The types of resins that can be used for photocuring 3D printing in the prior art are relatively limited, the fluidity of the photocuring precursor is difficult to control, and the contradiction between the printing speed and toughness of the printed product limits the development of photocuring 3D printing. The present invention broadens the range of types of photocurable resins, and the types of resins are not limited by the modification method. Some TPAE, SEBS, and POE polymers that are difficult to modify with double bonds but have excellent properties of high strength and high elasticity can also be used to prepare photocurable resins, and the fluidity of the photocurable elastomer slurry and the performance of the photocurable 3D printed products can be regulated by adjusting the diluent type, elastomer type, solid content, elastomer molecular weight, crosslinking agent content, and swelling agent content in the slurry formula, getting rid of the mutual restrictions between the fluidity and mechanical properties of traditional photocurable materials, and having a wider adjustment range. The preparation of the photocurable elastomer slurry in the present invention is simple, easy, and green and environmentally friendly. The obtained photocurable printed samples have good strength and toughness, and have great application potential in high-end manufacturing and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0026] Figure 3 This is a physical picture of the DLP light-curing 3D printed elastomer spline in Example 1.

[0027] Figure 4 The DSC curves of the primary melt crystallization process of TPAE resin powders with molecular weights of 10,000, 20,000 and 30,000 in Examples 1, 4 and 7 are shown.

[0028] Figure 5 The DSC curves of the secondary melting of TPAE resin powders with molecular weights of 10,000, 20,000 and 30,000 in Examples 1, 4 and 7 are shown.

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

[0030] Figure 7 It is a stress-strain curve diagram of the light-cured 3D printed specimens in Example 7, Example 10, and Example 11.

[0031] Figure 8 Graph showing the stress-strain curves of the photocurable 3D printed specimens in Examples 1-9. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with some specific embodiments.

[0033] Example 1

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

[0035] S1. Using a freezing mill to grind a TPAE resin with a molecular weight of 10,000 to obtain TPAE powder, and using a 35-mesh sieve to finely screen the TPAE powder to obtain TPAE powder with a particle size not exceeding 500 μm;

[0036] S2, swelling the TPAE powder in step S1 into the active diluent HEA, the mass ratio of the active diluent to the TPAE powder is 1:0.3, adding the swelling agent AA accounting for 1% of the molar amount of HEA, stirring evenly, and standing for 12 hours to obtain the TPAE premix;

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

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

[0039] S5. Post-curing the DLP printed strip in step S4 under ultraviolet light for 3 hours to obtain a DLP light-cured 3D printed model and an elastomer strip.

[0040] Example 2

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

[0042] S1. Using a freezing mill to crush a 10,000 molecular weight TPU resin to obtain a TPU powder, and using a 35-mesh sample sieve to finely screen the TPU powder to obtain a TPU powder with a particle size not exceeding 500 μm;

[0043] S2, MMA and BA are prepared into a compound diluent in a molar ratio of 1:1, the TPU powder in step S1 is swollen in the compound diluent of MMA and BA, the mass ratio of the compound diluent to the TPU powder is 1:0.1, and the swelling agent MAA accounting for 3% of the molar amount of the compound diluent is added, stirred evenly, and allowed to stand for 12 hours to obtain a TPU premix;

[0044] S3, adding 0.5% of the crosslinking agent BIS and 0.25% of the photoinitiator TPO-L in the molar amount of the compound diluent to the TPU premix obtained in step S2, stirring evenly to obtain a photocurable elastomer slurry that can be used for 3D printing;

[0045] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV laser light source SLA printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0046] S5. Post-curing the SLA printed strip in step S4 under ultraviolet light for 3 hours to obtain an SLA light-cured 3D printed elastomer strip.

[0047] Example 3

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

[0049] S1. Use a freezing mill to crush 10,000 molecular weight TPEE resin to obtain TPEE powder, and use a 35-mesh sample sieve to finely sieve the TPEE powder to obtain TPEE powder with a particle size not exceeding 500 μm;

[0050] S2, dissolving AAm into HEA to obtain a compound diluent, the molar ratio of HEA:AAm is 4:1, swelling the TPEE powder in step S1 into the compound diluent of HEA and AAm, the mass ratio of the compound diluent to TPEE powder is 1:0.5, adding 5% of the molar amount of the swelling agent AA to the compound diluent, stirring evenly, standing for 12 hours, and obtaining a TPEE premix;

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

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

[0053] S5. Post-curing the DLP printed strip in step S4 under visible light for 3 hours to obtain a DLP light-cured 3D printed elastomer strip.

[0054] Example 4

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

[0056] S1. Using a freezing mill to crush 20,000 molecular weight TPAE resin to obtain TPAE powder, and using a 35-mesh sample sieve to finely screen the TPAE powder to obtain TPAE powder with a particle size not exceeding 500 μm;

[0057] S2, swelling the TPAE powder in step S1 into the active diluent MA, the mass ratio of the active diluent to the TPAE powder is 1:0.3, adding the swelling agent AA accounting for 1% of the molar amount of MA, stirring evenly, and standing for 12 hours to obtain the TPAE premix;

[0058] S3, adding 0.1% of the crosslinking agent TMPT and 0.1% of the photoinitiator 2959 based on the molar amount of MA to the TPAE premix obtained in step S2, stirring evenly to obtain a photocurable elastomer slurry that can be used for 3D printing;

[0059] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV light source DLP printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0060] S5. Post-curing the DLP printed strip in step S4 under ultraviolet light for 3 hours to obtain a DLP light-cured 3D printed elastomer strip.

[0061] Example 5

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

[0063] S1. Using a freezing mill to crush a 20,000 molecular weight SBS resin to obtain SBS powder, and using 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 with TPGDA and IBOA in a molar ratio of 2:1, dissolve the SBS powder in step S1 in the compound diluent of TPGDA and IBOA, the mass ratio of the compound diluent to the SBS powder is 1:0.1, add a swelling agent MAA accounting for 3% of the molar amount of the compound diluent, stir evenly, and let stand for 12 hours to obtain an SBS premix;

[0065] S3, adding 0.5% of the crosslinking agent GPTA and 0.25% of the photoinitiator 1173 in the molar amount of the compound diluent to the SBS premix obtained in step S2, stirring evenly to obtain a photocurable elastomer slurry that can be used for 3D printing;

[0066] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV laser light source SLA printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0067] S5. Post-curing the SLA printed strip in step S4 under ultraviolet light for 3 hours to obtain an SLA light-cured 3D printed elastomer strip.

[0068] Example 6

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

[0070] S1. Using a freezing mill to crush a 20,000 molecular weight SEBS resin to obtain SEBS powder, and using a 35-mesh sample sieve to finely sieve the SEBS powder to obtain a SEBS powder with a particle size not exceeding 500 μm;

[0071] S2, dissolving AAm in HEA to obtain a compound diluent, the molar ratio of HEA:AAm is 4:1; swelling the SEBS powder in step S1 into the compound diluent of HEA and AAm, the mass ratio of the compound diluent to SEBS powder is 1:0.5, adding swelling agent AA accounting for 5% of the molar amount of the compound diluent, stirring evenly, and standing for 12 hours to obtain a SEBS premix;

[0072] S3, adding 1% of the molar amount of the crosslinking agent DTMPTTA and 0.5% of the visible light initiator 784 to the SEBS premix obtained in step S2, stirring evenly to obtain a light-curable elastomer slurry that can be used for 3D printing;

[0073] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a visible light source DLP printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0074] S5. Post-curing the DLP printed strip in step S4 under visible light for 3 hours to obtain a DLP light-cured 3D printed elastomer strip.

[0075] Example 7

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

[0077] S1. Using a freezing mill to crush TPAE resin with a molecular weight of 30,000 to obtain TPAE powder, and using a 35-mesh sample sieve to finely screen the TPAE powder to obtain TPAE powder with a particle size not exceeding 500 μm;

[0078] S2, swelling the TPAE powder in step S1 into the active diluent DPGDA, the mass ratio of the active diluent to the TPAE powder is 1:0.3, adding the swelling agent AA accounting for 1% of the molar amount of DPGDA, stirring evenly, and standing for 12 hours to obtain the TPAE premix;

[0079] S3, adding 0.1% of the cross-linking agent PETPA and 0.1% of the photoinitiator 184 accounting for 0.1% of the molar amount of DPGDA to the TPAE premix obtained in step S2, stirring evenly to obtain a photocurable elastomer slurry that can be used for 3D printing;

[0080] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV light source DLP printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0081] S5. Post-curing the DLP printed strip in step S4 under ultraviolet light for 3 hours to obtain a DLP light-cured 3D printed elastomer strip.

[0082] Example 8

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

[0084] S1. Using a freezing mill to crush SIS resin with a molecular weight of 30,000 to obtain SIS powder, and using a 35-mesh sample 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 with PETEA and TMPTA in a molar ratio of 3:1, dissolve the SIS powder in step S1 in the compound diluent of PETEA and TMPTA, the mass ratio of the compound diluent to SIS powder is 1:0.1, add a swelling agent MAA accounting for 3% of the molar amount of the compound diluent, stir evenly, and let stand for 12 hours to obtain a SIS premix;

[0086] S3, adding 0.5% of the crosslinking agent DPHA and 0.25% of the photoinitiator TPO in the molar amount of the compound diluent to the SIS premix obtained in step S2, stirring evenly to obtain a photocurable elastomer slurry that can be used for 3D printing;

[0087] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a UV laser light source SLA printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0088] S5. Post-curing the SLA printed strip in step S4 under ultraviolet light for 3 hours to obtain an SLA light-cured 3D printed elastomer strip.

[0089] Example 9

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

[0091] S1. Using a freezing mill to crush POE resin with a molecular weight of 30,000 to obtain POE powder, and using a 35-mesh sample sieve to finely screen the POE powder to obtain POE powder with a particle size not exceeding 500 μm;

[0092] S2, dissolving AAm in HEA to obtain a compound diluent, the molar ratio of HEA:AAm is 2:1, swelling the POE powder in step S1 into the compound diluent of HEA and AAm, the mass ratio of the compound diluent to POE powder is 1:0.5, adding a swelling agent AA accounting for 5% of the molar amount of the compound diluent, stirring evenly, and standing for 12 hours to obtain a POE premix;

[0093] S3, adding 1.0% of the crosslinking agent TMPTA and 0.5% of the visible light initiator 784 in the molar amount of the compound diluent to the POE premix obtained in step S2, stirring evenly to obtain a light-curable elastomer slurry that can be used for 3D printing;

[0094] S4, printing the photocurable elastomer slurry that can be used for 3D printing in step S3 on a visible light source DLP printer to obtain preliminarily cured dumbbell-shaped and long strip polymer splines;

[0095] S5. Post-curing the DLP printed strip in step S4 under visible light for 3 hours to obtain a DLP light-cured 3D printed elastomer strip.

[0096] Example 10

[0097] The other conditions of this embodiment are the same as those of embodiment 7, except that the molecular weight of the TPAE resin in this embodiment is 10,000.

[0098] Embodiment 11

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

[0100] Performance Testing

[0101] 1. Crystallinity test: The thermal properties of the TPAE resin powders with molecular weights of 10,000, 20,000 and 30,000 in Examples 1, 4 and 7 were tested by differential scanning calorimetry. The DSC curves of crystallization after primary melting are shown in FIG. Figure 4 As shown, the DSC curve of the secondary melting is as follows Figure 5 As shown, the crystallization temperatures of TPAE resins with molecular weights of 10,000, 20,000 and 30,000 are 96.3°C, 97.1°C and 83.3°C respectively, and the secondary melting points are 152°C, 149°C and 131°C respectively. TPAE with the same structural type but different molecular weights have different crystallization temperatures and melting points.

[0102] 2. Viscosity test: Figure 1 This is a physical picture 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 appears translucent.

[0103] At room temperature, the test was conducted in the dark. The shear rheology of the shear flow curves 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, it can be seen that the photosensitive resins prepared in Examples 7, 10 and 11 exhibit shear-thinning flow characteristics. Combined with the crystallinity test, it can be seen that in the same liquid phase formula, the TPAE with high crystallinity has more perfect crystal regions, the molecular chain segments are arranged more closely, and the swelling agent is difficult to enter between the segments to promote its swelling effect in the diluent. Therefore, the TPAE with higher crystallinity has lower swelling degree in the diluent and lower initial shear viscosity, and the TPAE with lower crystallinity has higher swelling degree in the diluent and higher initial shear viscosity.

[0104] 3. Mechanical properties test: Figure 3This is a physical picture of the dumbbell-shaped and long-shaped polymer splines prepared by DLP light-curing 3D printing using 10,000 molecular weight TPAE resin powder in Example 1. The surface of the spline is smooth and presents a translucent and slightly whitish appearance; Figure 2 This is a small airplane model obtained by DLP printing of 10,000 molecular weight TPAE resin powder in Example 1. The model has a smooth surface and high printing accuracy.

[0105] At room temperature, the light-cured 3D printed polymer strips in Examples 1-11 were subjected to tensile tests using a universal testing machine to obtain stress-strain curves of the strips. The results are shown in Figure 7 , Figure 8 shown.

[0106] from Figure 7 It can be seen that under the same liquid phase composition, the mechanical properties of the photocured strips prepared by TPAE with different crystallinity are also different. The crystallinity affects the fluidity of the photocured TPAE slurry by affecting the swelling effect of the photocured TPAE slurry, thereby affecting the printing effect and the mechanical properties of the photocured strips. Selecting TPAE with lower crystallinity will have a better swelling effect, the TPAE particles will be more evenly dispersed in the liquid phase, and the toughness of the photocured strips will be higher. However, when the swelling is too high, the proportion of liquid phase in the system is too low, the TPAE particles will agglomerate, the fluidity of the slurry will deteriorate, the photocured 3D printing effect will be poor, and the overall density of the photocured polymer will be uneven, which will lead to 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 deteriorates, and the toughness of the photocured 3D printed TPAE strips first increases and then decreases.

[0107] from Figure 8 It can be seen that the photocured strips in Example 9 show hard and brittle properties, and the fracture strength can reach about 30MPa. The photocured strips in Examples 3, 4, 6, and 7 show hard and tough properties, and yielding occurs during the stretching process. Among them, Example 4 has the best toughness, with a strength of 21MPa and an elongation at break of 259%. The photocured strips in Examples 1, 2, 5, and 8 show soft and tough properties, and the elongation at break is relatively high, which can reach about 300%. This shows that the mechanical properties of the photocured 3D printed polymer strips can be changed by adjusting the diluent type, elastomer type, elastomer molecular weight, swelling agent content and cross-linking agent content, and solid content of the photocured elastomer slurry, thereby obtaining photocured strips with different mechanical characteristics of soft and tough, hard and tough, or hard and brittle, giving the photocured 3D printed products a wide range of adjustable mechanical properties.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A photocurable elastomer slurry, characterized in that: The composition is prepared from thermoplastic elastomer powder, active diluent, cross-linking agent, photoinitiator and swelling agent.

2. The photocurable elastomer slurry according to claim 1, characterized in that: 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.

3. The photocurable elastomer slurry according to claim 1, characterized in that: The thermoplastic elastomer powder is obtained by freezing and crushing a thermoplastic elastomer, and the thermoplastic elastomer is one or more of a thermoplastic polyamide elastomer, a thermoplastic polyurethane elastomer, a thermoplastic polyester elastomer, a styrene-butadiene-styrene triblock copolymer, a poly(styrene-butadiene-ethylene-butylene-styrene) elastomer, a polystyrene-polyisoprene-polystyrene triblock copolymer and a polyolefin elastomer.

4. The photocurable elastomer slurry according to claim 1, characterized in that: The active diluent is one or more of methyl acrylate, methyl methacrylate, butyl acrylate, isobornyl acrylate, tripropylene glycol diacrylate, dipropylene glycol acrylamide, hydroxyethyl acrylate, diacrylate, pentaerythritol tetraacrylate and trimethylolpropane triacrylate.

5. The photocurable elastomer slurry according to claim 1, characterized in that: The crosslinking agent is one or more of polyethylene glycol diacrylate monomer, N,N'-methylenebisacrylamide, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, 3 (propoxy) propylene glycol triacrylate, (trimethylolpropane) tetraacrylate, pentaerythritol tetraacrylate, 4 (ethoxy) pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate.

6. The photocurable elastomer slurry according to claim 1, characterized in that: The photoinitiator is one or more of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-hydroxy-2-methyl-1-phenylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, phenyl-2,4,6-trimethylbenzoyl lithium phosphite, fluorinated diphenyl titanocene and bis(pentafluorophenyl) titanocene.

7. The photocurable elastomer slurry according to claim 1, characterized in that: The swelling agent is acrylic acid and / or methacrylic acid.

8. A method for preparing the photocurable elastomer slurry according to any one of claims 1 to 7, characterized in that: The steps include: S1, freeze-crushing and sieving the thermoplastic elastomer to obtain thermoplastic elastomer powder; S2, dispersing the thermoplastic elastomer powder in the active diluent and the swelling agent and swelling them for a certain period of time to obtain a premixed liquid; S3. Add a photoinitiator and a cross-linking agent to the premixed liquid, mix them evenly, and obtain a photocurable elastomer slurry.

9. Use of the photocurable elastomer slurry according to any one of claims 1 to 7 in photocurable 3D printing.

10. The use according to claim 9, characterized in that: The application includes: printing the photocurable elastomer slurry on a 3D printing device to initially fix the shape, and then post-curing it under ultraviolet light or visible light to obtain a printed sample.

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