Photocurable compositions based on room temperature phosphorescence modulation and 4D printing method

Abstract

This invention discloses a room-temperature phosphorescence-controlled photocurable composition and a 4D printing method. The room-temperature phosphorescence-controlled photocurable composition comprises: a bisphenol A-based epoxy resin; a polybasic acid; a catalyst; and a photoinitiator containing at least one dye molecule, said at least one dye molecule comprising at least one structure as shown in formulas (I) to (III). The 4D printing method comprises steps (S1) uniformly stirring the room-temperature phosphorescence-controlled photocurable composition at room temperature; and (S2) performing 4D printing using the room-temperature phosphorescence-controlled photocurable composition and an ultraviolet light source to obtain a cured product.

Description

Technical Field

[0001] This invention relates to a photocurable composition based on room temperature phosphorescence regulation and a 4D printing method, particularly to a photocurable composition obtained by using phosphorescent molecules as initiators during photocuring at room temperature and a 4D printing method for manufacturing a cured product using said photocurable composition. Background Technology

[0002] In recent years, room temperature phosphorescence (RTP) has attracted widespread attention due to its long lifetime and large Stokes shift. Unlike fluorescence emission, phosphorescence emission requires electrons to undergo an intersystem crossing process from singlet to triplet and then return from the lowest triplet state (T1) to the ground state (S0) via radiative transition. Therefore, due to factors such as molecular vibration and oxygen quenching, the realization of room temperature phosphorescence often requires providing a relatively rigid external environment for the luminescent molecules.

[0003] Photopolymerization technology refers to the rapid transformation of a material system from a liquid to a solid state under ultraviolet light. This technology is widely used in coatings, printing inks, and adhesives. Common photopolymer resin systems consist of oligomers, photoinitiators, reactive diluents, and other additives, with photoinitiators playing a crucial role as the active species. Traditional photopolymer materials remain colorless and transparent under ultraviolet light, making it difficult to monitor the degree and state of curing in real time. However, monitoring the degree and state of curing is essential for 4D printed products.

[0004] Therefore, it is necessary to provide a photocurable composition and 4D printing method based on room temperature phosphorescence regulation, which can use the emission intensity of phosphorescence to monitor the curing degree and state of the 4D printed product, so as to solve the problems existing in the prior art. Summary of the Invention

[0005] In view of this, the present invention provides a photocurable composition based on room temperature phosphorescence regulation and a 4D printing method. The photocurable composition based on room temperature phosphorescence regulation introduces molecules with specific structures as photoinitiators. Under the premise of ensuring a fast-response photocuring process, it realizes the controllable room temperature phosphorescence emission of the photocurable material, and simultaneously completes the real-time visualization monitoring of the internal state of the material, 4D printing, and shape memory process.

[0006] To achieve the above objectives, one embodiment of the present invention provides a photocurable composition based on room temperature phosphorescence regulation, comprising:

[0007] A bisphenol A type epoxy resin;

[0008] Monobasic acids;

[0009] A catalyst; and

[0010] A photoinitiator comprising at least one dye molecule, said at least one dye molecule having one of the structures shown in formulas (I) to (III) below:

[0011]

[0012] as well as

[0013]

[0014] Wherein, R is a methyl, ethyl, propyl, methoxy, or halogen atom.

[0015] In one embodiment of the present invention, the bisphenol A epoxy resin has a structure as shown in formula (IV):

[0016] Where n is an integer from 0 to 4.

[0017] In one embodiment of the present invention, the polyacid is acrylic acid, methacrylic acid, or 3-butenoic acid.

[0018] In one embodiment of the present invention, the catalyst is triethylamine, triethanolamine, or dipropylamine.

[0019] In one embodiment of the present invention, the photocurable composition based on room temperature phosphorescence control further comprises a diluent.

[0020] In one embodiment of the present invention, the diluent is diethylene glycol diacrylate, tripropylene glycol diacrylate, or pentaerythritol tetraacrylate.

[0021] Another embodiment of the present invention provides a 4D printing method, comprising the following steps:

[0022] (S1) The photocurable composition based on room temperature phosphorescence regulation, as described above, is uniformly stirred at room temperature; and

[0023] (S2) Using the room temperature phosphorescence-controlled photocurable composition and an ultraviolet light source, 4D printing is performed to obtain a cured product.

[0024] In one embodiment of the present invention, the wavelength of the ultraviolet light source is 300 to 450 nanometers.

[0025] In one embodiment of the present invention, the cured product emits phosphorescence under the ultraviolet light source.

[0026] In one embodiment of the present invention, the phosphorescence is blue phosphorescence, green phosphorescence, or orange phosphorescence.

[0027] The beneficial effects of this invention are:

[0028] The phosphorescent dye molecules doped in the room temperature phosphorescence-controlled photocurable composition of the present invention can all exhibit gradually enhanced room temperature phosphorescence emission during the ultraviolet curing process. They can themselves play the role of photo-initiating free radical polymerization reaction, and further realize the real-time monitoring process of photocurable materials.

[0029] The photocurable composition based on room temperature phosphorescence regulation of the present invention can be used for 4D printing, and the printed cured product can undergo reversible dynamic changes while emitting phosphorescence at room temperature.

[0030] The photocurable composition based on room temperature phosphorescence regulation of the present invention uses various materials that are simple and readily available, and are harmless to the human body and the environment. Attached Figure Description

[0031] Figure 1 The phosphorescence spectra of the CER-TCO system before and after UV curing in Example 1 are shown.

[0032] Figure 2 The phosphorescence lifetime of the CER-TCO system before and after UV curing in Example 1;

[0033] Figure 3 The phosphorescence spectra of the CER-BrEB system before and after UV curing in Example 2 are shown.

[0034] Figure 4 The phosphorescence lifetime of the CER-BrEB system before and after UV curing in Example 2;

[0035] Figure 5 The phosphorescence spectra of the CER-DTD system before and after UV curing in Example 3 are shown.

[0036] Figure 6 The phosphorescence lifetime of the CER-DTD system before and after UV curing in Example 3;

[0037] Figure 7 Images showing the phosphorescence changes during the UV curing process of the CER-TCO system in Example 1;

[0038] Figure 8 Images showing the phosphorescence changes during the UV curing process of the CER-BrEB system in Example 2;

[0039] Figure 9 Images showing the phosphorescence changes during the UV curing process of the CER-DTD system in Example 3;

[0040] Figure 10The images shown are 4D printed patterns of the diluted-CER-TCO UV-cured system in Example 1. The top row is a top view and the bottom row is a side view. The curing time of the flowers gradually decreases from left to right.

[0041] Figure 11 The images shown are 4D printed patterns of the diluted-CER-BrEB UV-cured system in Example 2. The top row is a top view and the bottom row is a side view. The curing time of the flowers gradually decreases from left to right.

[0042] Figure 12 The images shown are from the diluted-CER-DTD UV-cured 4D printing system of Example 3. The top row is a top view and the bottom row is a side view. The curing time of the flowers gradually decreases from left to right. Detailed Implementation

[0043] To make the above and other objects, features, and advantages of the present invention more apparent and understandable, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Furthermore, the singular forms “a,” “an,” and “described” used in this invention include plural references unless the context clearly specifies otherwise. Numerical ranges (e.g., 10% to 11% of A) include upper and lower limits unless specifically stated otherwise (i.e., 10% ≤ A ≤ 11%); if a numerical range does not define a lower limit (e.g., less than 0.2% of B, or B below 0.2%), it means that the lower limit may be 0 (i.e., 0% ≤ B ≤ 0.2%). The above terms are used to illustrate and understand the present invention, and not to limit the present invention.

[0044] An embodiment of the present invention provides a photocurable composition based on room temperature phosphorescence regulation, comprising: a bisphenol A-type epoxy resin; a polybasic acid; a catalyst; and a photoinitiator, wherein the photoinitiator comprises at least one dye molecule having a structure as shown in formula (I), (II), or (III) below:

[0045]

[0046] as well as

[0047]

[0048] In formulas (I) to (III) above, R is an alkyl group, such as methyl, ethyl, or propyl; R can also be an alkoxy group, such as methoxy; R can also be a halogen atom, such as chlorine (Cl) or bromine (Br), but is not limited thereto. As shown above, formula (I) contains a thiochromone molecular structure, formula (II) contains a bromobenzaldehyde molecular structure, and formula (III) contains a 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic dianhydride structure.

[0049] In one embodiment of the present invention, the bisphenol A epoxy resin has a structure as shown in formula (IV):

[0050]

[0051] In one embodiment, n in equation (IV) is an integer from 0 to 4, such as 0, 1, 2, 3 or 4.

[0052] In one embodiment of the present invention, the polyacid may be acrylic acid. Methacrylic acid or 3-butenoic acid.

[0053] In one embodiment of the present invention, the catalyst is triethylamine. Triethanolamine or dipropylamine.

[0054] In one embodiment of the present invention, the room-temperature phosphorescence-controlled photocurable composition further comprises a diluent. Preferably, the diluent is diethylene glycol diacrylate. Tripropylene glycol diacrylate.

[0055] Another embodiment of the present invention provides a 4D printing method, which mainly includes the following steps:

[0056] (S1) The photocurable composition based on room temperature phosphorescence regulation, as described above, is uniformly stirred at room temperature; and

[0057] (S2) Using the room temperature phosphorescence-controlled photocurable composition and an ultraviolet light source, 4D printing is performed to obtain a cured product.

[0058] In step (S1), the stirring time can be adjusted automatically until the various materials in the room-temperature phosphorescence-controlled photocurable composition are uniformly dispersed or the solid components are substantially dissolved. In one embodiment of the invention, the wavelength of the ultraviolet light source is 300 to 450 nanometers, and may be, for example, 300, 320, 350, 365, 380, 400, or 450 nanometers, but is not limited thereto, and may be any wavelength between 300 and 450 nanometers. Preferably, the cured product emits phosphorescence under the ultraviolet light source. In one embodiment, the phosphorescence is blue phosphorescence, green phosphorescence, or orange phosphorescence.

[0059] To verify the effectiveness of the room temperature phosphorescence-controlled photocurable composition of the present invention in 4D printing, the following experiments were conducted.

[0060] Example 1:

[0061] (1) Synthesis of a photocurable composition system based on formula (Ⅰ) (CER-TCO):

[0062] Bisphenol A epoxy resin of formula (IV) and acrylic acid were mixed at a mass ratio of 5:2, and 0.3 wt% (by weight) of photoinitiator of formula (I) was added. (TCO) and 3 wt% triethylamine were added, and the resulting mixture was stirred on a heating table at 70°C for 1 hour. Subsequently, it was stirred overnight at room temperature to obtain a homogeneous photocurable composition system, CER-TCO. The mixture was dropped onto a glass plate and exposed to 365 nm ultraviolet light; gradually increasing blue phosphorescence was observed, indicating that the photocurable composition had gradually completed curing. Figures 1-2 The image shows the changes in phosphorescence intensity and lifetime of the CER-TCO photocurable composition before and after curing, as well as a series of images showing the gradual enhancement of phosphorescence during the photocuring process.

[0063] (2) Diluted photopolymerization composition system (diluted-CER-TCO) for 4D printing methods:

[0064] 100 wt% diethylene glycol diacrylate was added to the above-mentioned CER-TCO photocurable composition system. The mixture was stirred overnight at room temperature to ensure homogeneity, thus obtaining the diluted-CER-TCO photocurable composition system for 4D printing.

[0065] Photopolymerization 4D printing using 365nm ultraviolet light allows for the production of cured products with varying degrees of curing by changing the ultraviolet light irradiation time. For example... Figure 7 As shown, due to the differences in the photocured surface of cured products with different degrees of curing and the solubility of uncured monomers, they can exhibit dynamic changes in different bending angles in dichloromethane solvent and emit blue phosphorescence under ultraviolet light.

[0066] Example 2:

[0067] (1) Synthesis of CER-BrEB, a photocurable composition system based on the structure of formula (II):

[0068] Bisphenol A epoxy resin of formula (IV) and acrylic acid were mixed at a mass ratio of 5:2, and 0.3 wt% of photoinitiator of formula (II) was added. (BrEB) and 3 wt% triethylamine were added, and the resulting mixture was stirred on a heating table at 70°C for 1 hour. Subsequently, it was stirred overnight at room temperature to obtain a homogeneous photocurable composition system, CER-BrEB. The mixture was dropped onto a glass plate and exposed to 365 nm ultraviolet light; gradually increasing green phosphorescence was observed, indicating that the photocurable composition had gradually completed curing. Figures 3-4The image shows the changes in phosphorescence intensity and lifetime of the CER-BrEB photocurable composition before and after curing, as well as a series of images showing the gradual enhancement of phosphorescence during the photocuring process.

[0069] (2) Diluted photopolymerization composition system (diluted-CER-BrEB) for 4D printing method:

[0070] 100 wt% diethylene glycol diacrylate was added to the above-mentioned CER-BrEB photocurable composition system. Stir overnight at room temperature to ensure homogeneity and obtain the photocurable composition system diluted-CER-BrEB for 4D printing.

[0071] Photopolymerization 4D printing using 365nm ultraviolet light allows for the production of cured products with varying degrees of curing by changing the ultraviolet light irradiation time. For example... Figure 8 As shown, due to the differences in the photocured surface of cured products with different degrees of curing and the solubility of uncured monomers, they can exhibit dynamic changes in different bending angles in dichloromethane solvent and emit green phosphorescence under ultraviolet light.

[0072] Example 3:

[0073] (1) Synthesis of CER-DTD photocurable system based on structure (III):

[0074] Bisphenol A epoxy resin of formula (IV) and acrylic acid were mixed at a mass ratio of 5:2, and 0.3 wt% of photoinitiator of formula (III) was added. (DTD) and 3 wt% triethylamine were added, and the resulting mixture was stirred on a heating table at 70°C for 1 hour. Subsequently, it was stirred overnight at room temperature to obtain a homogeneous photocurable composition system, CER-DTD. When the mixture was dropped onto a glass plate and exposed to 365 nm UV light, gradually increasing orange phosphorescence was observed, indicating that the photocurable composition had gradually completed curing. Figures 5-6 The image shows the changes in phosphorescence intensity and lifetime of the CER-BrEB photocurable composition before and after curing, as well as a series of images showing the gradual enhancement of phosphorescence during the photocuring process.

[0075] (2) Diluted CER-DTD photopolymerization system for 4D printing:

[0076] 100 wt% diethylene glycol diacrylate was added to the above-mentioned CER-DTD photocurable composition system. Stir overnight at room temperature to ensure homogeneity and obtain the photocurable composition system diluted-CER-DTD for 4D printing.

[0077] Photopolymerization 4D printing using 365nm ultraviolet light allows for the production of cured products with varying degrees of curing by changing the ultraviolet light irradiation time. For example... Figure 9 As shown, due to the differences in the photocured surface of cured products with different degrees of curing and the solubility of uncured monomers, they can exhibit dynamic changes in different bending angles in dichloromethane solvent and emit orange phosphorescence under ultraviolet light.

[0078] The photocurable compositions of Examples 1-3 described above gradually change from a liquid to a solid state under ultraviolet light irradiation. As the rigidity of the composition gradually increases, it emits progressively stronger room-temperature phosphorescence, such as... Figures 1-9 As shown, each image displays the changes in phosphorescence intensity and lifetime of the photocurable composition before and after curing, as well as a series of images showing the gradual enhancement of phosphorescence during the photocuring process in 4D printing.

[0079] In 4D printing, when the curing time is short, the degree of polymerization and rigidity of the cured product are small, and the cured product film is relatively soft, spontaneously generating a large bending angle in dichloromethane solution. In contrast, films with longer curing times can spontaneously generate a smaller bending angle. Figures 10-12 The study demonstrates the degree of petal bending at different curing times using the diluted photocurable compositions from Examples 1-3, with the photocuring time for the flowers decreasing progressively from left to right.

[0080] The photocurable composition of the present invention reacts and gradually cures under ultraviolet light irradiation, accompanied by gradually increasing room-temperature phosphorescence emission. Therefore, the UV curing process can be monitored by changes in luminescence intensity. With the addition of an appropriate amount of diluent, due to the different curing degrees on the upper and lower surfaces of the photocurable composition and the solubility of uncured monomers, it can exhibit reversible 4D dynamic changes in organic solvents.

[0081] The three photoinitiators used in the room-temperature phosphorescence-controlled photocurable composition of this invention include thiochromone molecules, bromobenzaldehyde molecules, and 1,4,5,8-naphthalenetetracarboxylic acid dianhydride molecules. These three types of molecules can initiate free radical polymerization reactions under the action of triethylamine, and as the rigidity of the polymer structure gradually increases, they exhibit tunable room-temperature phosphorescence emission.

[0082] The present invention has been described by the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, modifications and equivalents contained within the spirit and scope of the claims are included within the scope of the present invention.

Claims

1. A room temperature phosphor-based light-cured composition, characterized in that, The room temperature phosphorescence-regulated photocuring composition comprises: a bisphenol A type epoxy resin; a polyacid; a catalyst; and a photoinitiator comprising at least one dye molecule, the at least one dye molecule comprising at least one of the structures shown in the following formulas (II) to (III): wherein R is a methyl group, an ethyl group, a propyl group, a methoxy group, or a halogen atom; and the bisphenol A type epoxy resin has the structure shown in the following formula (IV): wherein n is an integer from 0 to 4; the polyacid is acrylic acid, methacrylic acid, or 3-butenoic acid; the catalyst is triethylamine, triethanolamine, or dipropylamine. It further comprises a diluent.

2. The room temperature phosphor-based modulation regulated photocuring composition according to claim 1, wherein The diluent is diethylene glycol diacrylate, tripropylene glycol diacrylate, or pentaerythritol tetraacrylate.

3. The room temperature phosphor-based modulation regulated photocuring composition according to claim 2, wherein The 4D printing method comprises the following steps:

4. A 4D printing method, characterized by, (S1) uniformly stirring the room temperature phosphorescence-regulated photocuring composition as claimed in claim 1 at room temperature; and (S2) using the room temperature phosphorescence-regulated photocuring composition and an ultraviolet light source to perform 4D printing to obtain a cured product. The wavelength of the ultraviolet light source is 300 to 450 nanometers.

5. The 4D printing method of claim 4, wherein, The cured product emits phosphorescence under the ultraviolet light source.

6. The 4D printing method of claim 4, wherein, The phosphorescence is green phosphorescence or orange phosphorescence.

7. The 4D printing method of claim 6, wherein, ​

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