A method for preparing a photocured resin for 4D printing

Abstract

The embodiment of the application discloses a kind of preparation methods of photocuring resin for 4D printing, comprising: epoxy acrylate resin oligomer and polyurethane acrylic resin oligomer are mixed according to mass ratio 5:0.1~5 to obtain photocuring resin oligomer;Acrylate and HEA are mixed according to mass ratio 0.1~2:1 to obtain diluent;1,3-Propyl sulfone lactone 1,3-PS and dimethylaminoethyl methacrylate DMAEMA are mixed according to molar ratio 1:0.8~1.2 to constitute zwitterionic crosslinking agent;Diluent, zwitterionic crosslinking agent and photoinitiator are sequentially placed in centrifugal tube and mixed uniformly into preheated photocuring resin oligomer, vortex oscillation is mixed and then transferred to ultrasonic cleaning machine and ultrasonic, vortex oscillation is stirred until the mixed solution is transparent and bubble-free;The mixed solution is introduced into a polypropylene mold, irradiated and cured under LED-UV lamp, to obtain a shape memory polymer, or a shape memory polymer product is prepared using a photocuring 3D printer.The method is simple, easy to operate, and the printed sample has excellent shape memory effect.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, and in particular relates to a method for preparing a photocurable resin for 3D printing. Background Technology

[0002] Shape memory polymer (SMP) is a typical smart material that can be deformed into other temporary shapes under certain conditions, and can be fixed in this temporary shape under environmental conditions. When stimulated by external factors again, it can actively return to its initial shape.

[0003] 3D printing is a crucial technology in the field of intelligent manufacturing. When smart materials are combined with 3D printing technology, 4D printing technology emerges, enabling a leap forward in additive manufacturing. Currently, the main focus of development is shape memory polymer 4D printing technology. However, the types of shape memory polymers currently available for 4D printing are quite limited, primarily thermoplastics such as polyurethane, polylactic acid, or polyethylene, and photocurable acrylates. More types of materials still need to be developed to meet diverse application needs. On the other hand, the acrylate compounds currently widely used in 4D printing suffer from drawbacks such as high volume shrinkage after curing and poor thermal stability, severely limiting the further development and application of these materials. Therefore, developing a 4D printing photosensitive resin with low odor, low volume shrinkage, and good stability is essential. Summary of the Invention

[0004] This invention provides a method for preparing a photocurable resin for 4D printing, comprising:

[0005] An epoxy acrylate resin oligomer and a polyurethane acrylate resin oligomer are mixed at a mass ratio of 5:0.1 to 5 to obtain a light-curable resin oligomer.

[0006] The diluent is obtained by mixing acrylate and HEA at a mass ratio of 0.1 to 2:1.

[0007] A zwitterionic crosslinking agent is prepared by mixing 1,3-propanesulfonic acid lactone (1,3-PS) and dimethylaminoethyl methacrylate (DMAEMA) at a molar ratio of 1:0.8–1.2.

[0008] Diluent, zwitterionic crosslinking agent and photoinitiator are placed into centrifuge tubes and mixed evenly. Preheated photocurable resin oligomer is added, and the mixture is vortexed and then transferred to an ultrasonic cleaner for ultrasonication. The mixture is vortexed and stirred repeatedly until the mixture is transparent and free of bubbles.

[0009] The mixture is poured into a polypropylene mold and cured under an LED-UV lamp to obtain a shape memory polymer, or a shape memory polymer product is prepared by using a photopolymerization 3D printer.

[0010] Furthermore, the mass ratio of the photocurable resin oligomer, diluent, and zwitterionic crosslinking agent is 0.1–2:0.1–2:0.01–1.

[0011] Furthermore, the epoxy acrylate resin oligomers include: bisphenol A epoxy acrylate, phenolic epoxy acrylate, or bisphenol F epoxy acrylate.

[0012] Furthermore, polyurethane acrylate resin oligomers include: difunctional aliphatic polyurethane acrylates, hexafunctional aliphatic polyurethane acrylates, polyurethane dimethacrylates, or difunctional aromatic polyurethane acrylates.

[0013] Furthermore, it also includes: acrylates including: hydroxyethyl acrylate, isobornyl acrylate, polyethylene glycol acrylate, tripropylene glycol acrylate, or triethylene glycol diacrylate.

[0014] Furthermore, it also includes:

[0015] N-methyldiethanolamine (MDEA) and 1,3-propanesulfonic acid lactone (PS) were dissolved in equal amounts of solvent and mixed at a molar ratio of 1:0.8 to 1.2. The mixture was stirred rapidly for 12 to 24 hours to obtain a white solid precipitate. The precipitate was filtered and dried to obtain the zwitterionic crosslinking agent.

[0016] Furthermore, it also includes:

[0017] Dimethylaminoethyl methacrylate (DMAEMA) and 1,3-propanesulfonic acid lactone (PS) were dissolved in equal amounts of solvent and mixed at a molar ratio of 1:0.8 to 1.2. The mixture was stirred rapidly for 12 to 24 hours to obtain a white solid precipitate, which was then filtered and dried to obtain an amphoteric crosslinking agent.

[0018] Furthermore, the photoinitiator includes: diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0019] Furthermore, the mass fraction of the photoinitiator is 0.01–5%.

[0020] Furthermore, the wavelength of the LED-UV lamp is 320–420 nm, and the curing time is 0.5–3 h.

[0021] The beneficial effects of this invention are as follows: By employing a strategy of enhancing the acrylate component through electrostatic interaction, complementary advantages are achieved. The system obtains high curing speed from the prepolymer component and high dimensional stability and oxygen insensitivity from the diluent and crosslinking agent components. By controlling the ratio of the prepolymer component to the diluent and crosslinking agent components, the final material possesses excellent toughness and shape memory properties. Furthermore, it can be adapted to photopolymer 3D printing equipment for the customization of complex, personalized, and diverse 3D structures, and the 3D structures exhibit excellent macroscopic shape memory properties. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a shape memory effect diagram of a 3D printed model of a photopolymer-curable 4D printable shape polymer in an embodiment of the present invention.

[0024] Figure 2 Infrared image of a printed sample as an example of the present invention;

[0025] Figure 3 and Figure 4 The graphs show the shape fixation rate and shape recovery rate after 10 cycles of shape memory according to the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0027] This invention provides a method for preparing a shape memory polymer for photopolymerization 4D printing, comprising:

[0028] Step 1: Mix epoxy acrylate resin oligomer and polyurethane acrylate resin oligomer at a mass ratio of 5:0.1-5 to obtain a light-curable resin oligomer;

[0029] Step 2: Mix acrylate and HEA at a mass ratio of 0.1 to 1:1 to obtain a diluent;

[0030] Step 3: Mix 1,3-propanesulfonic acid lactone (1,3-PS) and dimethylaminoethyl methacrylate (DMAEMA) at a molar ratio of 1:0.8-1.2 to form an amphoteric crosslinking agent;

[0031] Step 4: Place the diluent, zwitterionic crosslinking agent and photoinitiator into a centrifuge tube and mix them evenly. Add the preheated photocurable resin oligomer, vortex mix, and then transfer to an ultrasonic cleaner for ultrasonication. Vortex mix and repeat until the mixture is transparent and free of bubbles.

[0032] Step 5: Pour the mixture into a polypropylene mold and irradiate it under an LED-UV lamp to cure it, thereby obtaining a shape memory polymer, or use a photopolymer 3D printer to prepare shape memory polymer products.

[0033] Furthermore, the epoxy acrylate resin oligomers include: bisphenol A epoxy acrylate, phenolic epoxy acrylate, or bisphenol F epoxy acrylate.

[0034] Furthermore, polyurethane acrylate resin oligomers include: difunctional aliphatic polyurethane acrylates, hexafunctional aliphatic polyurethane acrylates, polyurethane dimethacrylates, or difunctional aromatic polyurethane acrylates.

[0035] Furthermore, it also includes: acrylates including: hydroxyethyl acrylate, isobornyl acrylate, polyethylene glycol acrylate, tripropylene glycol acrylate, or triethylene glycol diacrylate.

[0036] Furthermore, it also includes:

[0037] N-methyldiethanolamine (MDEA) and 1,3-propanesulfonic acid lactone (PS) were dissolved in equal amounts of solvent and mixed at a molar ratio of 1:0.8 to 1.2. The mixture was stirred rapidly for 12 to 24 hours to obtain a white solid precipitate. The precipitate was filtered and dried to obtain the zwitterionic crosslinking agent.

[0038] Furthermore, it also includes:

[0039] Dimethylaminoethyl methacrylate (DMAEMA) and 1,3-propanesulfonic acid lactone (PS) were dissolved in equal amounts of solvent and mixed at a molar ratio of 1:0.8 to 1.2. The mixture was stirred rapidly for 12 to 24 hours to obtain a white solid precipitate, which was then filtered and dried to obtain an amphoteric crosslinking agent.

[0040] Furthermore, the photoinitiator includes: diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0041] Furthermore, the mass fraction of the photoinitiator is 0.01–5%.

[0042] Furthermore, the wavelength of the LED-UV lamp is 320–420 nm, and the curing time is 0.5–3 h.

[0043] In one embodiment of the present invention, epoxy acrylate and polyurethane acrylate are mixed at a mass ratio of 9:1 to 6 to form an oligomer component, and acrylate monomer A and acrylate monomer B are mixed at a mass ratio of 1 to 4:1 to form an acrylate component. Under dark conditions, the oligomer component and diluent component are mixed at a mass ratio of 1:1 to 10, and an amphoteric crosslinking agent and a free radical photoinitiator are added to the mixture. The mixture is vortexed and then transferred to an ultrasonic cleaner for ultrasonication and vortexing. This process is repeated until the mixture is transparent and free of bubbles. The mixture is then poured into a polypropylene mold and cured under an LED-UV lamp to obtain a shape memory polymer. Alternatively, a shape memory polymer product can be prepared using a photopolymerization 3D printer. Figure 1 The image shown is a shape memory effect diagram of a 3D printed model of a photopolymer-curable 4D printable shape polymer in an embodiment of the present invention. Figure 2 Infrared image of a printed sample as an example of the present invention;

[0044] Figure 3 and Figure 4 This is a graph showing the shape fixation rate and shape recovery rate after 10 cycles of shape memory in this invention.

[0045] The photocurable resin in this invention features fast curing time, high hardness, and low odor. It comprises a prepolymer, a diluent, and a crosslinking agent. The zwitterionic crosslinking agent with electrostatic interaction constitutes 1-15% of the total system by mass, the acrylic prepolymer comprises 40-60%, and the diluent comprises 40-60%. The preparation method involves using an acrylate-containing resin as the prepolymer, an acrylic diluent, and the zwitterionic crosslinking agent as raw materials. These are mixed uniformly through stirring and ultrasonication to form a bubble-free, highly fluid 4D printing photocurable resin with shape memory properties. The preparation method is simple and easy to operate, producing printed samples with excellent shape memory effects. It can be applied to 4D printing, biomedicine, flexible robotics, aerospace, smart devices, or mechanical parts, breaking the limitations of traditional 3D printing and showing great promise in the 4D printing field.

[0046] Example 1

[0047] The shape memory polymer in this example was prepared according to the following steps:

[0048] First, under dark conditions, weigh 1.2g of bisphenol A epoxy acrylate and 0.8g of aliphatic polyurethane acrylate at a mass ratio of 6:4. Then, weigh 2.0g of hydroxyethyl acrylate at a mass ratio of 1:1. Add 0.28g of DMAPS and 0.08g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide, vortex mix for 1-3 minutes, and transfer to an ultrasonic cleaner for ultrasonication for 5 minutes. Then, vortex mix again, repeating the process several times until the system becomes transparent and free of bubbles.

[0049] The second step is to pour the mixed solution into a polypropylene mold and irradiate it under an LED-UV lamp (405nm) for 1.5 hours to cure it, thereby obtaining the shape memory polymer.

[0050] Example 2

[0051] First, under dark conditions, weigh 1.2g of bisphenol F epoxy acrylate and 0.8g of aliphatic polyurethane acrylate at a mass ratio of 6:4. Then, weigh 2.0g of hydroxyethyl acrylate at a mass ratio of 1:1. Add 0.28g of DMAPS and 0.08g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide, vortex mix for 1-3 minutes, and transfer to an ultrasonic cleaner for ultrasonication for 5 minutes. Then, vortex mix again. Repeat this process several times until the system becomes transparent and free of bubbles.

[0052] The second step is to pour the mixed solution into a polypropylene mold and irradiate it under an LED-UV lamp (405nm) for 1.5 hours to cure it, thereby obtaining the shape memory polymer.

[0053] Example 3

[0054] First, under dark conditions, weigh 1.2g of bisphenol A epoxy acrylate and 0.8g of aliphatic polyurethane acrylate at a mass ratio of 6:4. Then, weigh 2.0g of isobornyl acrylate at a mass ratio of 1:1. Add 0.28g of DMAPS and 0.08g of diphenyl-(2,4,6-trimethylbenzoyl)phosphorus oxide, vortex mix for 1-3 minutes, and transfer to an ultrasonic cleaner for ultrasonication for 5 minutes. Then, vortex mix again. Repeat this process several times until the system becomes transparent and free of bubbles.

[0055] The second step is to pour the mixed solution into a polypropylene mold and irradiate it under an LED-UV lamp (405nm) for 1.5 hours to cure it, thereby obtaining the shape memory polymer.

[0056] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

[0057] The above description is only a partial embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a photocured resin for 4D printing, characterized by, include: An epoxy acrylate resin oligomer and a polyurethane acrylate resin oligomer are mixed at a mass ratio of 5:0.1~5 to obtain a light-curable resin oligomer. The diluent is hydroxyethyl acrylate or isoborneol acrylate; The zwitterionic crosslinking agent is composed of 1,3-propanesulfonic acid lactone (PS) and dimethylaminoethyl methacrylate (DMAEMA) in a molar ratio of 1:0.8~1.

2. Diluent, zwitterionic crosslinking agent and photoinitiator are placed into centrifuge tubes and mixed evenly. Preheated photocurable resin oligomer is added, and the mixture is vortexed and then transferred to an ultrasonic cleaner for ultrasonication. The mixture is vortexed and stirred repeatedly until the mixture is transparent and free of bubbles. The mixture is poured into a polypropylene mold and cured under an LED-UV lamp to obtain a shape memory polymer, or a shape memory polymer product is prepared using a photopolymerization 3D printer.

2. The production method according to claim 1, characterized by, The mass ratio of the photocurable resin oligomer, diluent, and zwitterionic crosslinking agent is 0.1~2:0.1~2:0.01~1.

3. The preparation method according to claim 1, characterized in that, Epoxy acrylate resin oligomers include: bisphenol A epoxy acrylate, phenolic epoxy acrylate, or bisphenol F epoxy acrylate.

4. The preparation method according to claim 1, characterized in that, Polyurethane acrylate resin oligomers include: difunctional aliphatic polyurethane acrylate, hexafunctional aliphatic polyurethane acrylate, polyurethane dimethacrylate, or difunctional aromatic polyurethane acrylate.

5. The preparation method according to claim 1, characterized in that, The zwitterionic crosslinking agent is obtained by dissolving N-methyldiethanolamine (MDEA) and 1,3-propanesulfonic acid lactone (PS) in equal masses of solvent, mixing them at a molar ratio of 1:0.8~1.2, and then rapidly stirring the mixture for 12-24 hours to obtain a white solid precipitate, which is then filtered and dried.

6. The preparation method according to claim 1, characterized in that, The zwitterionic crosslinking agent is obtained by dissolving dimethylaminoethyl methacrylate (DMAEMA) and 1,3-propanesulfonic acid lactone (PS) in equal masses of solvent, mixing them at a molar ratio of 1:0.8~1.2, and then rapidly stirring the mixture for 12~24 hours to obtain a white solid precipitate, which is then filtered and dried.

7. The preparation method according to claim 1, characterized in that, Photoinitiators include: diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

8. The preparation method according to claim 6, characterized in that, The mass fraction of the photoinitiator is 0.01–5%.

9. The preparation method according to claim 1, characterized in that, The wavelength of the LED-UV lamp is 320-420nm, and the curing time is 0.5-3h.

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