Quantum dot printing ink and preparation method thereof

Abstract

The invention provides quantum dot printing ink. The quantum dot printing ink comprises the following components in percentage by mass: 10-30% of quantum dots, 20-50% of hydroxy acrylic resin, 1-10% of a functional monomer, 1-10% of modified epoxy resin, 0.1-2% of a photoinitiator, 0.1-1% of a flatting agent and 10-50% of a solvent, wherein the modified epoxy resin is acrylic acid modified epoxy resin. An acrylic acid structure is introduced into the epoxy resin, so that the compatibility of the epoxy resin with hydroxy acrylic resin, functional monomers and other components is enhanced, the dispersion of the components is facilitated, quantum dots are uniformly dispersed in an ink system, and the film forming uniformity of the ink is effectively enhanced; meanwhile, a plurality of active groups among the components are subjected to cross-linking action and generate intermolecular acting force to obtain a more three-dimensional net-shaped structure, the structure can adsorb the quantum dots, the quantum dot printing ink with better uniformity and stability is obtained, and the luminous efficiency of the quantum dot printing ink is improved.

Description

Technical Field

[0001] This invention relates to the field of quantum dot printing inks, and more specifically to a quantum dot printing ink and its preparation method. Background Technology

[0002] Quantum dot luminescent materials exhibit a significant quantum confinement effect, which endows them with properties such as tunable emission wavelength, high luminous efficiency, good photostability, long lifespan, and excellent solution processing performance. This makes them play a crucial role in various fields, including novel displays, LED lighting, bioimaging, and fluorescent labeling. Quantum dot ink is one of the representative applications of quantum dot luminescent materials.

[0003] In existing technologies, quantum dot inks typically involve directly dispersing quantum dot luminescent materials in a solvent. This method presents several challenges. For instance, using solvents with high dispersion stability, such as toluene and chloroform, results in quantum dot inks with low viscosity and boiling points. Conversely, using high-viscosity polymers as solvents leads to suboptimal dispersion of the quantum dot luminescent materials, affecting film uniformity. Furthermore, the introduced insulating polymer additives often reduce the charge transport capacity of the film. Additionally, quantum dot ligands may undergo dissociation equilibrium in complex solvent environments, and changes in the external environment can disrupt this equilibrium, impacting the ink's storage stability, uniformity, and luminescent efficiency.

[0004] In conclusion, it is necessary to develop a new technical solution to address the problems existing in the current technology. Summary of the Invention

[0005] This invention provides a quantum dot printing ink, prepared from quantum dots, hydroxyl acrylic resin, functional monomers, and modified epoxy resin. The modified epoxy resin is an acrylic-modified epoxy resin. By introducing an acrylic structure into the epoxy resin, its compatibility with the hydroxyl acrylic resin, functional monomers, and other components is enhanced, which facilitates component dispersion and allows the quantum dots to be uniformly dispersed in the ink system, effectively improving the film-forming uniformity of the ink. Simultaneously, because the modified epoxy resin possesses epoxy groups and an acrylic structure, after being compounded with the hydroxyl acrylic resin, functional monomers, and other components, various active groups between the components undergo cross-linking interactions and intermolecular forces, resulting in a more three-dimensional network structure. This structure can adsorb quantum dots, yielding a quantum dot printing ink with better uniformity and stability, and improving its luminous efficiency.

[0006] One object of the present invention is to provide a quantum dot printing ink, the quantum dot printing ink comprising the following components in parts by mass:

[0007]

[0008]

[0009] in,

[0010] The modified epoxy resin is an acrylic-modified epoxy resin.

[0011] Furthermore, the quantum dots are selected from one or more of the following groups: IIB-VIA, IIIA-VA, IVA-VIA, IB-IIIA-VIA, IIB-IVA-VIA, IIA-IVB-VA, and VIII-VIA single or composite structure quantum dots or perovskite quantum dots.

[0012] Furthermore, the functional monomer is trimethylolpropane trimethacrylate.

[0013] Furthermore, the photoinitiator is selected from one or more of benzoyl groups, aromatic phosphine oxides, benzophenones, alkyl phenyl ketones, or benzoyl carboxyl esters.

[0014] Furthermore, the leveling agent is selected from one or more of acrylic leveling agents, silicone leveling agents, or fluorine leveling agents.

[0015] Furthermore, the solvent is selected from one or more of alcohols, ethers, glycol ether acetates, acetonitrile, dimethyl sulfoxide, or dimethylformamide.

[0016] Another object of the present invention is to provide a method for preparing the above-mentioned quantum dot printing ink, comprising the following steps:

[0017] S1. Epoxy resin and o-hydroxyaniline are blended and heated to react, yielding an intermediate product;

[0018] S2. The intermediate product, acrylic acid and tri(2-hydroxyethyl)isocyanurate triacrylate are mixed and heated to react, thereby obtaining the modified epoxy resin.

[0019] S3. Quantum dots, hydroxyl acrylic resin, functional monomers, the modified epoxy resin, photoinitiator, leveling agent and solvent are mixed evenly to obtain quantum dot printing ink.

[0020] Furthermore, the mass ratio of the epoxy resin to o-hydroxyaniline is 1:(1-3).

[0021] Furthermore, in step S1, the heating temperature is 50-70°C, and the reaction time is 30-60 min.

[0022] Furthermore, the mass ratio of the intermediate product, acrylic acid, and tri(2-hydroxyethyl)isocyanurate triacrylate is 1:(0.5-2):(0.01-0.05).

[0023] Furthermore, in step S2, the heating temperature is 90-120℃, and the reaction time is 30-60 min.

[0024] The present invention has the following beneficial effects:

[0025] This invention provides a quantum dot printing ink, prepared from quantum dots, hydroxyl acrylic resin, functional monomers, and modified epoxy resin. The modified epoxy resin is an acrylic-modified epoxy resin. By introducing an acrylic structure into the epoxy resin, its compatibility with the hydroxyl acrylic resin, functional monomers, and other components is enhanced, which facilitates component dispersion and allows the quantum dots to be uniformly dispersed in the ink system, effectively improving the film uniformity of the ink. Simultaneously, because the modified epoxy resin possesses epoxy groups and an acrylic structure, after being compounded with the hydroxyl acrylic resin, functional monomers with multiple arms and active groups, and other components, cross-linking and intermolecular forces occur between the components, resulting in a more three-dimensional network structure. This structure can adsorb quantum dots, yielding a quantum dot printing ink with better uniformity and stability, and improving its luminous efficiency. Detailed Implementation

[0026] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0027] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0028] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0029] The following raw materials are used in the embodiments of the present invention:

[0030] The quantum dots used in the embodiments and comparative examples of this invention are red CdSe / ZnS quantum dots.

[0031] The hydroxy acrylic resin used in the embodiments and comparative examples of this invention is poly(2-hydroxyethyl methacrylate), brand name V32805, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0032] The functional monomer used in the embodiments and comparative examples of this invention is trimethylolpropane trimethacrylate.

[0033] The photoinitiator used in the embodiments and comparative examples of this invention is photoinitiator 184.

[0034] The leveling agent used in the embodiments and comparative examples of this invention is BYK358N.

[0035] The solvent used in the embodiments and comparative examples of this invention is propylene glycol methyl ether acetate.

[0036] The epoxy resin E51 used in the embodiments and comparative examples of this invention was purchased from Hubei Xinrunde Chemical Co., Ltd.

[0037] Example 1

[0038] A quantum dot printing ink, the quantum dot printing ink comprising the following components in parts by weight:

[0039]

[0040]

[0041] The preparation method of the above-mentioned quantum dot printing ink includes the following steps:

[0042] S1. 20 parts of epoxy resin E51 and 50 parts of o-hydroxyaniline were mixed and stirred at 70°C for 40 min. The mixture was then filtered, washed and dried to obtain the intermediate product.

[0043] S2. The intermediate product, 70 parts of acrylic acid and 1.8 parts of tri(2-hydroxyethyl)isocyanurate triacrylate were mixed and reacted at 100°C for 40 min. The mixture was then filtered, washed and dried to obtain the modified epoxy resin.

[0044] S3. According to the above-mentioned mass proportions, quantum dots, hydroxyl acrylic resin, functional monomer, the modified epoxy resin, photoinitiator, leveling agent and solvent are mixed and stirred evenly to obtain quantum dot printing ink.

[0045] Example 2

[0046] A quantum dot printing ink, the quantum dot printing ink comprising the following components in parts by weight:

[0047]

[0048] The preparation method of the quantum dot printing ink is the same as in Example 1.

[0049] Example 3

[0050] A quantum dot printing ink, the quantum dot printing ink comprising the following components in parts by weight:

[0051]

[0052] The preparation method of the quantum dot printing ink is the same as in Example 1.

[0053] Comparative Example 1

[0054] A quantum dot printing ink, the difference between this comparative example and Example 1 is that step S2 is omitted. In step S3, the modified epoxy resin is replaced by an intermediate product, while the dosage of other components and the preparation method are the same as in Example 1.

[0055] Comparative Example 2

[0056] A quantum dot printing ink, the difference between this comparative example and Example 1 is that steps S1 and S2 are omitted, and in step S3, the modified epoxy resin is replaced with epoxy resin E51 by mass. The other component amounts and preparation methods are the same as in Example 1.

[0057] Test case

[0058] (1) The quantum dot printing inks prepared in Examples 1-3 and Comparative Examples 1-2 were printed into 20×30μm red quantum dot layers with a resolution of 200×200ppi using an inkjet printer. The layers were then heated to 100°C on a hot plate under a nitrogen flow vacuum of 1×10⁻⁶. -6 After evaporation and drying under Torr for 30 min, a monochromatic quantum dot luminescent layer was obtained, and then its film uniformity was tested using a white light interferometer.

[0059] (2) A quantum dot light-emitting diode (LED) in which the above-mentioned monochromatic quantum dot light-emitting layer is applied to a positive-type quantum dot LED, comprising: a substrate, an anode disposed on the surface of the substrate, a hole transport layer disposed on the surface of the anode, a quantum dot light-emitting layer disposed on the surface of the hole transport layer, an electron transport layer disposed on the surface of the quantum dot light-emitting layer, and a cathode disposed on the surface of the electron transport layer. The anode is made of ITO, the hole transport layer is made of TFB, the quantum dot light-emitting layer is the above-mentioned monochromatic quantum dot light-emitting layer, the electron transport layer is made of ZnO, and the cathode is made of Al. The external quantum efficiency (EQE) of the above-mentioned quantum dot LED is tested using an EQE optical testing instrument.

[0060] The test results are shown in Table 1.

[0061] Table 1 Performance Test Results

[0062] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Film uniformity % 73 72 71 55 53 External quantum efficiency % 12.2 11.7 11.3 6.2 5.8

[0063] The test results above show that Examples 1-3 of the present invention have better film uniformity and external quantum efficiency, indicating that the quantum dots in the embodiments of the present invention can be more uniformly dispersed in the ink system, have better stability, and can effectively improve ink flow and stability in inkjet printing and other processes, resulting in better uniformity of the printed film. Simultaneously, the present invention also has better external quantum efficiency and better luminescent performance. In contrast, Comparative Examples 1-2, which replace the modified epoxy resin with intermediate products and epoxy resin E51 respectively, have relatively poor compatibility between components, making it difficult to form a three-dimensional structure, thus resulting in poorer performance of the quantum dot printing ink.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0065] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A quantum dot printing ink, characterized in that, The quantum dot printing ink comprises the following components in parts by weight: in, The modified epoxy resin is an acrylic-modified epoxy resin.

2. The quantum dot printing ink according to claim 1, characterized in that, The quantum dots are selected from one or more of the following groups: IIB-VIA, IIIA-VA, IVA-VIA, IB-IIIA-VIA, IIB-IVA-VIA, IIA-IVB-VA, and VIII-VIA, including single or composite quantum dots or perovskite quantum dots.

3. The quantum dot printing ink according to claim 1, characterized in that, The functional monomer is trimethylolpropane trimethacrylate.

4. The quantum dot printing ink according to claim 1, characterized in that, The photoinitiator is selected from one or more of benzoyl groups, aromatic phosphine oxides, benzophenones, alkyl phenyl ketones, or benzoyl carboxyl esters.

5. The quantum dot printing ink according to claim 1, characterized in that, The leveling agent is selected from one or more of acrylic leveling agents, silicone leveling agents, or fluorine leveling agents.

6. A method for preparing the quantum dot printing ink according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Epoxy resin and o-hydroxyaniline are blended and heated to react, yielding an intermediate product; S2. The intermediate product, acrylic acid and tri(2-hydroxyethyl)isocyanurate triacrylate are mixed and heated to react, thereby obtaining the modified epoxy resin. S3. Quantum dots, hydroxyl acrylic resin, functional monomers, the modified epoxy resin, photoinitiator, leveling agent and solvent are mixed evenly to obtain quantum dot printing ink.

7. The method for preparing quantum dot printing ink according to claim 6, characterized in that, The mass ratio of the epoxy resin to o-hydroxyaniline is 1:(1-3).

8. The method for preparing quantum dot printing ink according to claim 6, characterized in that, In step S1, the heating temperature is 50-70℃, and the reaction time is 30-60 min.

9. The method for preparing quantum dot printing ink according to claim 6, characterized in that, The mass ratio of the intermediate product, acrylic acid, and tri(2-hydroxyethyl)isocyanurate triacrylate is 1:(0.5-2):(0.01-0.05).

10. The method for preparing quantum dot printing ink according to claim 6, characterized in that, In step S2, the heating temperature is 90-120℃, and the reaction time is 30-60 min.

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