Composite material and preparation method thereof, and optical conversion device

Abstract

The present disclosure provides a composite material and a preparation method thereof, and a photoconversion device, wherein the composite material comprises an oleophilic continuous phase, a first discontinuous phase and a second discontinuous phase dispersed in the continuous phase, and an emulsifier located at the interface between the first discontinuous phase and the continuous phase, wherein the emulsifier is an oil-in-water type surfactant, the first discontinuous phase comprises a plurality of microstructures, the second discontinuous phase comprises an oil-soluble wavelength conversion material, and the microstructure comprises a water-soluble protective agent and a dispersion medium for dispersing the protective agent. Since unfavorable substances such as water and oxygen will be preferentially captured by the microstructure after continuing to enter the composite material containing the wavelength conversion material, the wavelength conversion material is protected from being corroded by these unfavorable substances and becoming ineffective, thereby improving the stability and life of the composite material.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic technology, and in particular to a composite material and a preparation method thereof, and a photoconversion device. Background Art

[0002] In recent years, given the special chemical and physical properties of quantum dots, they have broad application prospects in the fields of photoluminescent devices, solid-state lighting, displays, biomedicine, etc. The key step in applying quantum dots to the above fields is to deviceize quantum dots, of which quantum dot films are an effective means. The most commonly used method for preparing quantum dot films is to disperse quantum dots directly into polymers, and then prepare quantum dot films by spraying, spin coating, etc. However, the chemical stability of quantum dots themselves is insufficient, and they are easy to react with water and oxygen, causing quantum dots to fail and denature, affecting the luminescence performance of the device. In order to prevent water and oxygen from invading quantum dots, barrier films are usually set on the upper and lower sides of the quantum dot film, which can block water and oxygen from the outside. However, the higher the water and oxygen barrier rate of the barrier film, the higher the price of the barrier film, and the four sides of the quantum dot film are not covered with barrier films. After water vapor enters the quantum dot film, it will still cause the quantum dot material to fail rapidly. Summary of the invention

[0003] The purpose of the present disclosure is to provide a composite material, comprising a lipophilic continuous phase, a first discontinuous phase and a second discontinuous phase dispersed in the continuous phase, and an emulsifier located at the interface between the first discontinuous phase and the continuous phase, wherein the emulsifier is an oil-in-water type surfactant, the first discontinuous phase comprises a plurality of microstructures, the second discontinuous phase comprises an oil-soluble wavelength conversion material, and the microstructures comprise a water-soluble protective agent and a dispersion medium for dispersing the protective agent.

[0004] Optionally, the microstructure is in liquid, solid or gel state.

[0005] Optionally, the protective agent is selected from one or more of the group consisting of a water absorbent, an oxygen scavenger, a free radical scavenger and an ultraviolet absorber.

[0006] Optionally, the difference between the control group composite material and the above composite material is that the first discontinuous phase and the emulsifier are not included, and the difference between the refractive index of the control group composite material and the refractive index of the above composite material is within ±0.5.

[0007] Optionally, the initial average size of the microstructure is less than 0.5 μm; after the composite material is placed in air at room temperature and pressure for 7 to 10 days, the average size of the microstructure is 0.8 to 1.5 μm.

[0008] Optionally, the above-mentioned dispersion medium includes at least one hydrophilic polymer; preferably, the monomer forming the above-mentioned hydrophilic polymer is selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid.

[0009] Optionally, the continuous phase comprises at least one lipophilic polymer; preferably, the lipophilic polymer is selected from one of polyamide, polyurethane, polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol-lactic acid-glycolic acid copolymer, polyethylene glycol, polyhydroxybutyric acid, polyhydroxyalkyl ester, polybutylene succinate, polyterephthalate, polyhydroxyalkanoic acid and acrylic resin.

[0010] Optionally, the water absorbent includes one or more, and the water absorbent is selected from one of ionic liquid, polyvinyl alcohol, aluminum oxide, magnesium oxide, sodium sulfate, potassium sulfate, magnesium sulfate, calcium chloride, silica gel and aluminosilicate.

[0011] Optionally, the above-mentioned oxygen scavenger includes one or more, and the above-mentioned oxygen scavenger is selected from inorganic salt oxygen scavengers, organic matrix oxygen scavengers or photosensitivity dye deoxidizers. Preferably, the above-mentioned oxygen scavenger is selected from one of sulfites, enzymes, ascorbic acid, water-soluble photosensitizers and water-soluble singlet oxygen acceptors.

[0012] Optionally, the free radical scavenger includes one or more, and the free radical scavenger is selected from one of p-benzoquinone, 2-methyl-2-nitrosomethane, phenyl-N-tert-butylnitrone and a metal complex quencher.

[0013] Optionally, the above-mentioned ultraviolet absorber includes one or more, and the above-mentioned ultraviolet absorber is selected from one of nano ZnO, nano TiO2, talcum powder, salicylates, benzotriazoles, substituted acrylonitriles, and triazines.

[0014] Optionally, the dispersion medium comprises at least one organic solvent, and preferably the organic solvent is selected from one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran.

[0015] Optionally, the above-mentioned dispersion medium includes auxiliary solvent water; preferably, the solubility of the above-mentioned protective agent in the above-mentioned auxiliary solvent water is recorded as S mg, and the weight ratio between the above-mentioned protective agent and the above-mentioned auxiliary solvent water is (0.85S~S):0.1 or (0.9S~S):0.1.

[0016] Optionally, the weight ratio between the protective agent and the continuous phase is 1:20 to 3:20, and the weight ratio between the protective agent and the wavelength conversion material is 2:1 to 10:1.

[0017] The present disclosure also provides a photoconversion device, comprising any of the above-mentioned composite materials.

[0018] Optionally, the mass of the adverse substances in the continuous phase accounts for 0% to 10% of the total mass of the adverse substances in the photoconversion device, the mass of the adverse substances in the microstructure accounts for 90% to 100% of the total mass of the adverse substances, and the adverse substances are water, oxygen or free radicals.

[0019] The present disclosure also provides a method for preparing a composite material, comprising the following steps: S1, mixing and dispersing a raw material of a hydrophilic first non-continuous phase, a raw material of a lipophilic continuous phase, and an oil-in-water surfactant to form a first non-continuous phase dispersed in the raw material of the continuous phase, wherein the first non-continuous phase includes a plurality of microstructures, and the microstructures include a water-soluble protective agent and a dispersion medium for dispersing the protective agent; S2, mixing and dispersing an oil-soluble wavelength conversion material with the dispersion system obtained in S1 to form a second non-continuous phase dispersed in the raw material of the continuous phase, wherein the second non-continuous phase includes the wavelength conversion material; S3, curing the dispersion system obtained in S2 to obtain the composite material.

[0020] Optionally, the protective agent is selected from one or more of the group consisting of a water absorbent, an oxygen scavenger, a free radical scavenger and an ultraviolet absorber.

[0021] Optionally, in the above S1, the above dispersion medium includes at least one hydrophilic monomer or hydrophilic polymer; preferably, the above hydrophilic monomer and the monomer forming the above hydrophilic polymer are independently selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid.

[0022] Optionally, the dispersion medium comprises at least one organic solvent, and preferably the organic solvent is selected from one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran.

[0023] Optionally, the above-mentioned dispersion medium includes auxiliary solvent water and a main dispersion medium, and the above-mentioned main dispersion medium is selected from at least one of a water-soluble monomer, a water-soluble polymer and an organic solvent; the above-mentioned S1 includes: pre-mixing the above-mentioned protective agent and the above-mentioned auxiliary solvent water to form a mixed liquid, and then mixing and dispersing the above-mentioned mixed liquid with the above-mentioned main dispersion medium and the raw materials of the above-mentioned continuous phase; preferably, the solubility of the above-mentioned protective agent in the above-mentioned auxiliary solvent water is recorded as S mg, and the weight ratio between the above-mentioned protective agent and the above-mentioned auxiliary solvent water is (0.85S~S):0.1 or (0.9S~S):0.1.

[0024] Optionally, the auxiliary solvent water accounts for 15-20% by mass in the dispersion medium.

[0025] Optionally, the raw materials of the above-mentioned continuous phase include at least one lipophilic monomer or lipophilic polymer; preferably, the above-mentioned lipophilic polymer is selected from one of polyamide, polyurethane, polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol-lactic acid-glycolic acid copolymer, polyethylene glycol, polyhydroxybutyric acid, polyhydroxyalkyl ester, polybutylene succinate, polyterephthalate, polyhydroxyalkanoic acid and acrylic resin, and the above-mentioned lipophilic monomer is selected from one of the monomers that form the above-mentioned lipophilic polymer.

[0026] Optionally, the weight ratio between the protective agent and the raw material of the continuous phase is 1:20 to 3:20, and the weight ratio between the protective agent and the wavelength conversion material is 2:1 to 10:1.

[0027] By applying the technical solution provided by the present disclosure, that is, a composite material is provided with a plurality of microstructures containing a protective agent in a continuous phase in which a wavelength conversion material is dispersed. The protective agent can quickly absorb adverse substances such as water vapor, oxygen, free radicals or ultraviolet rays in the composite material (for the wavelength conversion material). Since the content of the above-mentioned adverse substances in the microstructure is higher than that in the continuous phase, there is a concentration difference between the two, which will generate osmotic pressure, so that the above-mentioned adverse substances will be preferentially captured by the microstructure after continuing to enter the composite material, thereby protecting the wavelength conversion material from being corroded by these adverse substances and becoming ineffective, thereby improving the stability and life of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0029] Figure 1 A schematic diagram showing the structure of a composite material in some embodiments of the present application is shown;

[0030] Figure 2 A transmission electron microscope (TEM) image of the composite material just produced in Example 1 of the present application is shown;

[0031] Figure 3 The TEM of the composite material of Example 1 of the present application after being placed in air (relative humidity of about 50% Rh, room temperature and normal pressure) for 7 days is shown;

[0032] Figure 4 The TEM of the composite material of Example 1 of the present application after being placed in air for 7 days is shown. Figure 3 The observation magnification is magnified by 1 times.

[0033] Reference numerals:

[0034] 1. Continuous phase; 2. Microstructure; 3. Wavelength conversion material. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, method, system, product or equipment comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0037] The term "lipophilicity" refers to the property of a material that cannot be wetted by water when it comes into contact with water in the air. The term "hydrophilicity" refers to the property of a material that can be wetted by water when it comes into contact with water in the air. Wetting is the process by which water is adsorbed by the surface of a material. When the cohesive force of the interaction between the material molecules and the water molecules is greater than the cohesive force between the water molecules, the water molecules can quickly spread out on the surface of the material. At this point, at the intersection of the material, water and air, the angle formed by the tangent along the surface of the water droplet and the surface of the material (called the wetting angle) θ≤90°, and the material is hydrophilic; if θ>90°, the material is lipophilic.

[0038] The term "oil-soluble" refers to substances that are easily soluble or soluble in non-polar organic solvents but poorly soluble or slightly soluble in water. The term "water-soluble" refers to substances that are easily soluble or soluble in water. Based on the solubility of substances at 20°C, their solubility in water is divided into the following levels: solubility above 10g is "easy soluble", 1g to 10g is "soluble", 0.01g to 1g is "slightly soluble", and below 0.01g is "poorly soluble".

[0039] The term "surfactant" refers to a substance that can significantly change the interfacial state of its solution system when added in a small amount. It has fixed hydrophilic and lipophilic groups and can be arranged in a directional manner on the surface of the solution. The molecular structure of the surfactant is amphiphilic: one end is a hydrophilic group and the other end is a hydrophobic group. Surfactants are divided into two categories: water-in-oil type (W / O type) and oil-in-water type (O / W type). The former disperses the water phase into the oil phase, and the latter disperses the oil phase into the water phase.

[0040] One aspect of the present application provides a composite material, comprising a lipophilic continuous phase, a first discontinuous phase and a second discontinuous phase dispersed in the continuous phase, and an emulsifier located at the interface between the first discontinuous phase and the continuous phase, wherein the emulsifier is an oil-in-water type surfactant, the first discontinuous phase comprises a plurality of microstructures, the second discontinuous phase comprises an oil-soluble wavelength conversion material, and the microstructures comprise a water-soluble protective agent and a dispersion medium for dispersing the protective agent.

[0041] The composite material provided in the present application has multiple microstructures containing protective agents arranged in a continuous phase in which a wavelength conversion material is dispersed. The protective agent can quickly absorb adverse substances such as water vapor, oxygen, free radicals or ultraviolet rays in the composite material (for the wavelength conversion material). Since the content of the above-mentioned adverse substances in the microstructure is higher than that in the continuous phase, there is a concentration difference between the two, which will generate osmotic pressure, so that the above-mentioned adverse substances will be preferentially captured by the microstructure after continuing to enter the composite material, thereby protecting the wavelength conversion material from being corroded by these adverse substances and becoming ineffective, thereby improving the stability and life of the composite material.

[0042] In some embodiments, the composite material further comprises a third discontinuous phase dispersed in the continuous phase, and the third discontinuous phase may comprise at least one of a water-soluble protective agent and an oil-soluble protective agent. These protective agents located outside the microstructure are beneficial to promoting the improvement of the stability of the composite material.

[0043] In some embodiments, the dispersion medium includes at least one hydrophilic polymer. The monomers forming the hydrophilic polymer are preferably selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid, but are not limited thereto. The hydrophilic polymer can be a substance formed by polymerization of the same monomers or a substance formed by copolymerization of different monomers.

[0044] In some embodiments, the dispersion medium includes at least one organic solvent. The organic solvent may be selected from but not limited to at least one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran, which have good solubility for water-soluble protective agents and are miscible with water, so that the microstructure will not be destroyed due to phase separation after the water absorbent absorbs water vapor. In some embodiments, when the dispersion medium includes both the above-mentioned organic solvent and a hydrophilic polymer, the water-soluble protective agent can be dissolved in the hydrophilic polymer (it may also be dissolved in a hydrophilic monomer before curing), and the solubility of the organic solvent to the protective agent does not need to be particularly limited, and the dispersion medium as a whole exhibits hydrophilicity.

[0045] In some embodiments, the dispersion medium includes auxiliary solvent water. Since the water-soluble protective agent can be dissolved in water, adding auxiliary solvent water to the dispersion medium helps to fully dissolve the protective agent, thereby facilitating the formation of the microstructure. In the above embodiments, since the amount of auxiliary solvent used is very small, the dispersion medium also needs to include at least one hydrophilic polymer and / or at least one organic solvent.

[0046] In a preferred embodiment, assuming that the solubility of the protective agent in the auxiliary solvent is S mg, the weight ratio between the protective agent and the auxiliary solvent is (0.85S-S):0.1 or (0.9S-S):0.1.

[0047] The physical state of the microstructure is mainly affected by the dispersion medium therein. Depending on the dispersion medium contained in the microstructure, the microstructure can be in liquid, solid or gel state.

[0048] In some embodiments, the microstructure is in liquid state, and the dispersion medium is the above-mentioned organic solvent, or the dispersion medium is a mixture of at least two of water, organic solvent, and the first hydrophilic polymer. Among them, the network size of the first hydrophilic polymer needs to be larger than the water molecules or organic solvent molecules, which is conducive to the free passage of water molecules or organic solvent molecules through the network of the first hydrophilic polymer, so that the dispersion medium containing the first hydrophilic polymer is in liquid state. The above-mentioned organic solvent may include one or more organic solvents. The organic solvent may be selected from but not limited to at least one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran.

[0049] In some embodiments, the microstructure is solid and the dispersion medium is a hydrophilic polymer. However, in the process of preparing the composite material, the dispersion medium may also include a low-boiling point organic solvent. The organic solvent is basically completely volatilized during the curing in the following step S3, and the hydrophilic polymer is cross-linked and cured. The microstructure of the composite material finally obtained is solid.

[0050] In some embodiments, the microstructure is in a gel state, and the material of the dispersion medium is a mixture of water and a second hydrophilic polymer. The network size of the second hydrophilic polymer is slightly smaller than that of water molecules, and the water molecules are blocked in the network of the second hydrophilic polymer, thereby forming a gel-state microstructure.

[0051] In addition, when the dispersion medium includes the above-mentioned hydrophilic polymer, the physical state of the microstructure may also be affected by the degree of polymerization, degree of crosslinking, degree of polymer chain entanglement and affinity of the hydrophilic polymer.

[0052] In some embodiments, the protective agent is selected from one or more of the group consisting of a moisture absorbent, an oxygen scavenger, a free radical scavenger, and an ultraviolet absorber.

[0053] In some embodiments, the water absorbing agent is one or more, and the water absorbing agent is selected from one of ionic liquid, polyvinyl alcohol, aluminum oxide, magnesium oxide, sodium sulfate, potassium sulfate, magnesium sulfate, calcium chloride, silica gel and aluminosilicate.

[0054] In some embodiments, the oxygen scavenger is one or more, and the oxygen scavenger is selected from inorganic salt oxygen scavengers, organic matrix oxygen scavengers or photosensitive dye deoxidizers; the oxygen scavenger can be selected from but not limited to one of sulfites, enzymes, ascorbic acid, water-soluble photosensitizing dyes and water-soluble singlet oxygen acceptors (belonging to organic matrix oxygen scavengers). The oxygen scavenger is a type of substance that can react with oxygen or can absorb oxygen, wherein when the microstructure containing the photosensitive dye is exposed to light of a suitable wavelength, the excited dye molecules will sensitize the oxygen molecules that penetrate into the microstructure into singlet oxygen, and the singlet oxygen molecules will then react with the singlet oxygen acceptor molecules and be consumed, thereby achieving the removal of oxygen.

[0055] Under light or heating conditions, various free radicals are generated in the composite material during production and use, and these free radicals are likely to damage the quantum dot structure, and the free radical scavenger in the microstructure can absorb the free radicals. In some embodiments, the free radical scavenger is one or more, and the free radical scavenger is selected from one of p-benzoquinone, 2-methyl-2-nitrosomethane, phenyl-N-tert-butylnitrone and a metal complex quencher.

[0056] Under ultraviolet light conditions, during the production and use of composite materials, wavelength conversion materials (such as quantum dots) are more susceptible to erosion by heat, water vapor, oxygen, etc., which may cause the wavelength conversion materials to fail. In the prior art, ultraviolet blocking layers are often set on both sides of the light conversion layer or the emission layer, but they cannot effectively eliminate the influence of ultraviolet rays inside the light conversion layer or the emission layer. The present application achieves effective protection of the wavelength conversion material by setting a plurality of microstructures containing ultraviolet absorbers in the composite material. In some embodiments, the ultraviolet absorber is one or more, and the ultraviolet absorber is selected from nano ZnO, nano TiO 2 , talc, salicylates, benzotriazoles, substituted acrylonitriles, and triazines.

[0057] The above examples do not constitute a limitation on the types of protective agents of the present application, and those skilled in the art can select protective agents with appropriate affinity according to actual needs.

[0058] In some embodiments, the continuous phase includes at least one lipophilic polymer. The lipophilic polymer can be selected from, but not limited to, one of polyamide, polyurethane, polylactic acid, polyglycolic acid, polylactic acid-co-glycolic acid, polyethylene glycol-co-lactic acid-co-glycolic acid, polyethylene glycol, polyhydroxybutyric acid, polyhydroxyalkyl ester, polybutylene succinate, poly(terephthalate), polyhydroxyalkanoic acid and acrylic resin.

[0059] In some embodiments, the weight ratio of the protective agent to the continuous phase is 1:20 to 3:20, and the weight ratio of the protective agent to the wavelength conversion material is 2:1 to 10:1. The weight of the protective agent here refers to the weight of all protective agents included in the composite material.

[0060] In some embodiments, the weight ratio between the protective agent and the continuous phase is 1.2:20 to 2:20, and the weight ratio between the protective agent and the wavelength conversion material is 7.5:1 to 10:1.

[0061] In some embodiments, the microstructure further includes a suspending dispersant, such as fumed silica powder, which can promote the stability of the microstructure.

[0062] In some embodiments, the wavelength conversion material may be at least one of a quantum dot material, a nanorod material, a nanosheet material, and the like.

[0063] In some embodiments, a control group composite material is prepared for comparison, and the difference between the control group composite material and the composite material provided in this embodiment is that the first discontinuous phase and the emulsifier are not included, and the difference in the refractive index of the control group composite material and the refractive index of the composite material provided in this embodiment is within ±0.5. This shows that the microstructure can play the role of diffusion particles, can change the refraction of light passing through the composite material, and optimize the overall optical properties of the composite material.

[0064] In some embodiments, after the microstructure absorbs adverse substances such as water vapor, oxygen, free radicals or ultraviolet rays, its volume will increase, further exacerbating the difference in refractive index between the microstructure and the continuous phase, thereby enhancing the light diffusion effect of the microstructure. This effect on the refractive index may be positive or negative. When the protective agent in the microstructure reaches saturation in absorbing the adverse substances, the size of the microstructure will remain stable. The initial average size of the microstructure (i.e., when the composite material is just made) is less than 0.5 μm; after the composite material is placed in the air (environmental conditions: relative humidity of about 50% Rh, room temperature and normal pressure) for 7 to 10 days, the protective agent absorbs the adverse substances, and the average size of the microstructure is 0.8 to 1.5 μm. The average size of the microstructure is calculated by measuring its refractive index and taking the average value, or tested by a dynamic light scattering instrument, or directly observed by an electron microscope.

[0065] In some embodiments, the volume of one or more microstructures may remain unchanged before and after absorbing the adverse agent.

[0066] Another aspect of the present application provides a photoconversion device, comprising any of the above-mentioned composite materials. Since the above-mentioned composite material contains a protective agent arranged in a microstructure, the wavelength conversion material is effectively protected, the erosion of adverse substances such as water oxygen and free radicals is avoided or reduced, and the stability and life of the wavelength conversion material are improved. Therefore, the photoconversion device containing it also has higher stability and life. The above-mentioned photoconversion device can be a quantum dot film, a diffusion plate, an LED package, etc.

[0067] In some embodiments, the mass of the unfavorable substance in the continuous phase accounts for 0% to 10% of the total mass of the unfavorable substance in the photoconversion device, and the mass of the unfavorable substance in the microstructure accounts for 90% to 100% of the total mass of the unfavorable substance, and the unfavorable substance is water, oxygen or free radicals. The total mass of the unfavorable substance is obtained by incremental calculation under a single variable environment. For example, the sample is acted on for a period of time under oxygen-isolated high humidity conditions, and the mass change before and after the action is calculated, which is the mass of water absorbed by the photoconversion device.

[0068] Another aspect of the present application provides a method for preparing a composite material, comprising the following steps: S1, mixing and dispersing a hydrophilic raw material of a first non-continuous phase, a lipophilic raw material of a continuous phase, and an oil-in-water surfactant to form a first non-continuous phase dispersed in the raw material of the continuous phase, wherein the first non-continuous phase includes a plurality of microstructures, and the microstructures include a water-soluble protective agent and a dispersion medium for dispersing the protective agent; S2, mixing and dispersing an oil-soluble wavelength conversion material with the dispersion system obtained in S1 to form a second non-continuous phase dispersed in the raw material of the continuous phase, wherein the second non-continuous phase includes the wavelength conversion material; S3, curing the dispersion system obtained in S2 to obtain a composite material.

[0069] The preparation method of the composite material provided in the present application is to mix the raw materials of the hydrophilic first non-continuous phase and the raw materials of the lipophilic continuous phase, and form an emulsion system by utilizing the difference in affinity between the two. At the same time, the oil-in-water surfactant acts as an emulsifier to further stabilize the microstructure. Since the raw materials of the first non-continuous phase contain a water-soluble protective agent, after curing, the protective agent located in the microstructure can quickly absorb water vapor, oxygen, free radicals or ultraviolet rays and other adverse substances in the composite material, so that the content of the above-mentioned adverse substances in the microstructure is higher than that in the continuous phase. There is a concentration difference between the two, and osmotic pressure will be generated. Therefore, the above-mentioned adverse substances will be preferentially captured by the microstructure after continuing to enter the composite material, thereby protecting the wavelength conversion material from being corroded by these adverse substances and becoming ineffective, thereby improving the stability and life of the composite material.

[0070] It should be noted that the microstructures in S1 and S2 are in liquid state, and the microstructure of S3 after solidification may be in liquid, solid or gel state depending on the dispersion medium.

[0071] In some embodiments, a small portion of the water-soluble protective agent in S1 may be dispersed in the raw material of the continuous phase to form a third discontinuous phase dispersed in the raw material of the continuous phase; and / or, in S2, the oil-soluble protective agent, the oil-soluble wavelength conversion material and the dispersion system obtained in S1 are mixed and dispersed to form a third discontinuous phase dispersed in the raw material of the continuous phase. The oil-soluble protective agent is selected from one or more of the group consisting of oil-soluble deoxidizers, oil-soluble free radical scavengers and oil-soluble ultraviolet absorbers. The oil-soluble deoxidizer can be selected from at least one of oxime deoxidizers (e.g., dimethyl ketone oxime, acetaldehyde oxime, etc.), hydrazine, oil-soluble photosensitizers and oil-soluble singlet oxygen acceptors, but is not limited thereto. The oil-soluble free radical scavenger can be selected from at least one of 2,2-diphenyl-1-trinitrophenylhydrazine and tetramethylbenzoquinone, but is not limited thereto. The oil-soluble ultraviolet absorber can be selected from at least one of benzophenone substances, but is not limited thereto.

[0072] The physical state of the microstructure is mainly affected by the dispersion medium therein. In some embodiments, the microstructure is in a liquid state, and the dispersion medium is the above-mentioned organic solvent, or the dispersion medium is a mixture of at least two of water, an organic solvent, and a first hydrophilic polymer. Among them, the network size of the first hydrophilic polymer needs to be larger than the water molecules or the organic solvent molecules, which is conducive to the free passage of water molecules or organic solvent molecules through the network of the first hydrophilic polymer, so that the dispersion medium containing the first hydrophilic polymer is in a liquid state. The above-mentioned organic solvent may include one or more organic solvents. The organic solvent may be selected from but not limited to at least one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran.

[0073] In some embodiments, the microstructure is solid and the dispersion medium is a hydrophilic polymer. However, in the process of preparing the composite material, the dispersion medium may also include a low-boiling point organic solvent, which is substantially completely volatilized during the curing step S3 described below, and the hydrophilic polymer is cross-linked and cured, and the microstructure of the composite material finally obtained is solid. Preferably, the boiling point of the low-boiling point organic solvent does not exceed 40°C.

[0074] In some embodiments, the microstructure is in a gel state, and the material of the dispersion medium is a mixture of water and a second hydrophilic polymer. The network size of the second hydrophilic polymer is slightly smaller than that of water molecules, and the water molecules are blocked in the network of the second hydrophilic polymer, thereby forming a gel-state microstructure.

[0075] In addition, when the dispersion medium includes the above-mentioned hydrophilic polymer, the physical state of the microstructure may also be affected by the degree of polymerization, degree of crosslinking, degree of polymer chain entanglement and affinity of the hydrophilic polymer.

[0076] In some embodiments, the hydrophile-lipophile balance value of the water-in-oil surfactant is between 3 and 6. Examples may be glyceryl monostearate, fatty acid glyceride, polyglyceryl distearate, monoalkyl phosphate, hexadecanoate, sorbitan fatty acid ester, and the like.

[0077] In some embodiments, in S1, the dispersion medium includes at least one hydrophilic monomer or hydrophilic polymer. In some embodiments, an initiator or a cross-linking agent is added to the dispersion medium to initiate a curing reaction in the first non-continuous phase in S3; in other embodiments, there is no need to add an initiator or a cross-linking agent to the dispersion medium, and the hydrophilic monomer or polymer in the dispersion medium is cured by a dry method. When the raw material of the continuous phase and the first non-continuous phase are cured in the same manner, for example, the corresponding initiator or cross-linking agent is added respectively, and cured by heating (or light), then the raw material of the continuous phase and the first non-continuous phase are preferably cured simultaneously. When the raw material of the continuous phase is thermally cured or photocured, and the first non-continuous phase is cured by drying, the curing of the two can be achieved simultaneously or in steps.

[0078] In some embodiments, the hydrophilic monomer and the monomer forming the hydrophilic polymer can be independently selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid, but is not limited thereto. The hydrophilic polymer can be a substance formed by polymerization of the same monomer or a substance formed by copolymerization of different monomers.

[0079] In some embodiments, the dispersion medium includes at least one organic solvent. The organic solvent may be selected from at least one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran, but is not limited thereto. It is understood that, while or after S3 is being solidified, it may also include volatilization of at least part of the organic solvent in the dispersion medium, and the degree of volatilization can be adjusted by controlling the temperature and pressure to achieve a preset microstructure state.

[0080] In some embodiments, the organic solvent used as the dispersion medium may be selected from hydrophilic organic solvents.

[0081] In some embodiments, the dispersion medium includes auxiliary solvent water and a main dispersion medium, and the main dispersion medium is selected from at least one of a hydrophilic monomer, a hydrophilic polymer, and an organic solvent; S1 includes: premixing the protective agent and the auxiliary solvent water to form a mixed liquid, and then mixing and dispersing the mixed liquid with the main dispersion medium and the raw materials of the continuous phase. Since the water-soluble protective agent can be dissolved in water, adding the auxiliary solvent water to the dispersion medium helps to fully dissolve the protective agent, thereby facilitating the formation of the microstructure.

[0082] In some embodiments, the solubility of the protective agent in the auxiliary solvent water is recorded as S mg, and the weight ratio between the protective agent and the auxiliary solvent water is (0.85S~S):0.1 or (0.9S~S):0.1.

[0083] In some embodiments, the auxiliary solvent water accounts for 15-20% by weight of the entire dispersion medium.

[0084] In some embodiments, the protective agent is selected from one or more of the group consisting of a water absorbent, a deoxidizer, a free radical scavenger and a UV absorber. Examples of water absorbents, deoxidizers, free radical scavengers and UV absorbers have been given above and will not be repeated here.

[0085] In certain embodiments, the raw material of the continuous phase includes at least one lipophilic monomer or lipophilic polymer. The lipophilic polymer can be selected from but not limited to one of polyamide, polyurethane, polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol-lactic acid glycolic acid copolymer, polyethylene glycol, polyhydroxybutyric acid, polyhydroxyalkanoate, polybutylene succinate, polyterephthalate, polyhydroxyalkanoic acid and acrylic resin, and the lipophilic monomer is selected from one of the monomers forming the above-mentioned lipophilic polymer. In certain embodiments, the raw material of the continuous phase includes an initiator or a crosslinking agent for the curing reaction of the raw material of the continuous phase in S3.

[0086] In some embodiments, the weight ratio of the protective agent to the raw material of the continuous phase is 1:20 to 3:20, and the weight ratio of the protective agent to the wavelength conversion material is 2:1 to 10:1. The weight of the protective agent here refers to the weight of all protective agents included in the composite material.

[0087] In some embodiments, the weight ratio between the protective agent and the continuous phase is 1.2:20 to 2:20, and the weight ratio between the protective agent and the wavelength conversion material is 7.5:1 to 10:1.

[0088] Before step S3, the present application also provides a composition, including a raw material of a lipophilic continuous phase, a first discontinuous phase and a second discontinuous phase dispersed in the raw material of the continuous phase, the first discontinuous phase including a plurality of microstructures, the second discontinuous phase including an oil-soluble wavelength conversion material, and the microstructures including a water-soluble protective agent and a dispersion medium for dispersing the protective agent.

[0089] In some embodiments, the composition further includes an emulsifier located at the interface between the raw materials of the first discontinuous phase and the continuous phase, and the emulsifier is a water-in-oil surfactant.

[0090] In some embodiments, the dispersion medium includes at least one hydrophilic monomer or hydrophilic polymer. The hydrophilic monomer and the monomer forming the hydrophilic polymer can be independently selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid, but is not limited thereto.

[0091] In some embodiments, the dispersion medium includes at least one organic solvent. The organic solvent may be selected from at least one of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran, but is not limited thereto.

[0092] In some embodiments, the dispersion medium further includes an auxiliary solvent, water.

[0093] In some embodiments, the raw material of the continuous phase includes at least one lipophilic monomer or lipophilic polymer. The lipophilic polymer can be selected from, but not limited to, one of polyamide, polyurethane, polylactic acid, polyglycolic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol-lactic acid-glycolic acid copolymer, polyethylene glycol, polyhydroxybutyric acid, polyhydroxyalkyl ester, polybutylene succinate, polyterephthalate, polyhydroxyalkanoic acid and acrylic resin, and the lipophilic monomer can be selected from one of the monomers forming the lipophilic polymer.

[0094] The present application is further described in detail below in conjunction with specific embodiments.

[0095] Example 1

[0096] 1. Weigh 50 parts by mass of aliphatic polyurethane acrylate, 35 parts by mass of 2-ethylhexyl methacrylate, 15 parts by mass of acryloyl morpholine, and 0.2 parts by mass of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer to obtain a raw material of a continuous phase; add 5 parts by mass of polyethylene glycol (degree of polymerization 200) monolaurate to the raw material of the continuous phase, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer; then add 2 parts by mass of a saturated aqueous solution of polyvinyl alcohol (degree of polymerization 2000, degree of alcoholysis 80) as a water absorbent, 1 part by mass of magnesium sulfate and ferric sulfate as auxiliary water absorbents, 2 parts by mass of sulfite as an oxygen scavenger, and 1 part by mass of 2-methyl-2-nitrosomethane as a free radical scavenger, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer;

[0097] 2. Add 1 part by mass of oil-soluble quantum dot particles into the system and stir at a speed of 2000 r / min for 5 min using a rubber mixer;

[0098] 3. Apply the above mixture on two PET films to form a "sandwich structure" and perform UV light curing; the curing process is: 365nm UV curing, and the curing energy is 500-5000MJ / cm 2 A quantum dot film is obtained, in which the microstructure is in a liquid state.

[0099] Figure 2 The TEM of the composite material just made in this embodiment is shown, wherein the black dots are quantum dot particles, and the gray dots may be TPO, excess protective agent or microstructures. Since most of the microstructures at this time are very small, it is difficult to observe clearly through an electron microscope. It is speculated that the initial average size of the microstructure is less than 0.5μm. Figure 3 and Figure 4 TEM images of the composite material of this embodiment at different magnifications after being placed in air at room temperature for 7 days are shown. At this time, the average size of the microstructure is about 1 μm, especially from Figure 4 It can be clearly observed that the interior of the microstructure contains a large amount of liquid, and the quantum dot particles are completely distributed outside the microstructure.

[0100] Example 2

[0101] 1. Weigh 35 parts by mass of poly(terephthalate), 35 parts by mass of cyclohexyl methacrylate, 30 parts by mass of isobornyl methacrylate, and 0.3 parts by mass of TPO, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer to obtain the raw materials of the continuous phase; add 5 parts by mass of glycerol monolaurate to the raw materials of the continuous phase, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer; then add 2 parts by mass of ionic liquid as a water absorbent, 1 part by mass of an enzyme deoxidizer, and 2 parts by mass of ZnO as a UV absorber, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer;

[0102] 2. Add 1 part by mass of oil-soluble quantum dot particles into the system and stir at a speed of 2000 r / min for 5 min using a rubber mixer;

[0103] 3. Apply the above mixture on two PET films to form a "sandwich structure" and perform UV light curing; the curing process is: 365nm UV curing, and the curing energy is 500-5000MJ / cm 2 A quantum dot film is obtained, in which the microstructure is in a liquid state.

[0104] Example 3

[0105] 1. Weigh 75 parts by mass of polylactic acid-glycolic acid copolymer, 20 parts by mass of n-butyl acrylate, 0.5 parts by mass of azobisisobutyronitrile (AIBN), and 5 parts by mass of crosslinking agent triethylamine, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer to obtain a raw material of a continuous phase; add 25 parts by mass of diglycerol monolaurate to the raw material of the continuous phase, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer;

[0106] 2. Grind 1 part by mass of magnesium sulfate and aluminum sulfate powder, add them to 1 part by mass of a saturated aqueous solution of polyvinyl alcohol, add 2 parts by mass of a photosensitizing dye and 2 parts by mass of a singlet oxygen acceptor as a co-oxidizer, add 2 parts by mass of p-benzoquinone as a free radical scavenger, and 2 parts by mass of benzotriazole as an ultraviolet absorber, stir until the mixture is evenly dispersed, and add the mixture to the mixture obtained in step 1;

[0107] 3. Add 1 part by mass of oil-soluble quantum dots into the system and stir at a speed of 2000 r / min for 5 min using a rubber mixer;

[0108] 4. The mixture obtained in step 3 is applied on the surface and surrounding of a common blue light LED chip by dispensing, and placed in an oven at 110° C. for 12 hours for curing. A QD-LED device is obtained, in which the microstructure is in liquid state.

[0109] Example 4

[0110] Weigh 100 parts by mass of methyl methacrylate, grind 5 parts by mass of magnesium sulfate and aluminum sulfate powder, add 5 parts by mass of polyvinyl alcohol saturated aqueous solution, add 5 parts by mass of sulfite as a deoxidizer, 25 parts by mass of glycerol monolaurate, and then add 7.5 parts by mass of oil-soluble quantum dot microspheres, stir to make the mixture dispersed evenly, add to the main extruder, extrude, roll (smooth roll) press cooling and cutting to obtain a quantum dot diffusion plate. The microstructure is solid.

[0111] Example 5

[0112] 1. Weigh 6 parts by mass of vinyl pyrrolidone, 3.5 parts by mass of acrylamide, 0.5 parts by mass of N,N-methylenebisacrylamide, and 0.15 parts by mass of benzophenone carboxylate as aqueous phase photoinitiator, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer to obtain a raw material of a discontinuous phase; then add 3 parts by mass of a saturated aqueous solution of polyvinyl alcohol as a water absorbent, 2 parts by mass of ascorbic acid and 2 parts by mass of sulfite as deoxidizers, 3 parts by mass of 2-methyl-2-nitrosomethane as a free radical scavenger, 1 part by mass of nano ZnO and 1 part by mass of TiO 2As a UV absorber, a rubber mixer was used to stir at a speed of 2000 r / min for 5 min;

[0113] 2. Weigh 40 parts by mass of aliphatic polyurethane acrylate, 35 parts by mass of cyclohexyl methacrylate, 25 parts by mass of isobornyl methacrylate, and 0.2 parts by mass of TPO, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer to obtain a raw material of a continuous phase; add 5 parts by mass of polyethylene glycol (200) monolaurate to the raw material of the continuous phase, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer; then add the discontinuous phase material in step 1, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer;

[0114] 3. Add 1.5 parts by mass of oil-soluble quantum dot particles into the system and stir at a speed of 2000 r / min for 5 min using a rubber mixer;

[0115] 4. Coat the above mixture on two PET films to form a "sandwich structure" and perform UV light curing; the curing process is: 365nm UV curing, and the curing energy is 500-5000MJ / cm 2 A quantum dot film is obtained, in which the microstructure is in a gel state.

[0116] Comparative Example 1

[0117] 1. Weigh 50 parts by mass of aliphatic polyurethane acrylate, 35 parts by mass of 2-ethylhexyl methacrylate, 15 parts by mass of acryloyl morpholine, and 0.2 parts by mass of TPO, stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer, then add 2 parts by mass of a saturated aqueous solution of polyvinyl alcohol as a water absorbent, 1 part by mass of magnesium sulfate and ferric sulfate as auxiliary water absorbents, 2 parts by mass of sulfite as a deoxidizer, and 1 part by mass of 2-methyl-2-nitrosomethane as a free radical scavenger, and stir them at a speed of 2000 r / min for 5 minutes using a rubber mixer;

[0118] 2. Add 1 part by mass of oil-soluble quantum dot particles into the system and stir at a speed of 2000 r / min for 5 min using a rubber mixer;

[0119] 3. Coat the above mixture on two PET films to form a "sandwich structure" and perform UV light curing to obtain a quantum dot film. The curing process is: 365nm UV curing, curing energy is 500-5000MJ / cm 2 .

[0120] Comparative Example 2

[0121] Weigh 100 parts by mass of methyl methacrylate, grind 5 parts by mass of magnesium sulfate and aluminum sulfate powder, add 5 parts by mass of a saturated aqueous solution of polyvinyl alcohol, add 5 parts by mass of sulfite as a deoxidizer, and then add 7.5 parts by mass of oil-soluble quantum dot microspheres, stir to disperse the mixture evenly, add it to the main extruder, extrude it, roll (smooth roll) press, cool and cut it to obtain a quantum dot diffusion plate.

[0122] Take appropriate amount of the mixture in the last step of each embodiment and comparative example, and cure with 365nm UV at a curing energy of 500-5000MJ / cm 2 , a simple composite material is obtained. The refractive index of the composite material without microstructure and the composite material with microstructure are measured by a refractometer and the difference between the two is calculated; the "composite material without microstructure" in the refractive index measurement object specifically refers to the composite material obtained by mixing and dispersing the raw materials of the continuous phase and the wavelength conversion material used in the embodiment and then curing; the "composite material containing microstructure" refers to the above composite material obtained by the preparation method of this embodiment. The water permeability and oxygen permeability of the above composite material are measured by a water vapor and oxygen permeability meter. After the above composite material is placed in the air (relative humidity of about 50% Rh, room temperature and normal pressure) for 7 days, the average size of the microstructure in each composite material is tested by an electron transmission microscope.

[0123] The following tests were performed on the photoconversion devices (quantum dot films, QD-LED devices or quantum dot diffusion plates) of all the examples and comparative examples. The initial luminous flux and color coordinates were tested with an integrating sphere to calculate the luminous efficiency of the quantum dots in the photoconversion devices. Each photoconversion device (except the QD-LED device of Example 3) was aged under 70°C blue light for 7 days with a light intensity of 0.3 W / cm 2 The luminous flux and color coordinates were tested again with an integrating sphere to calculate the luminous efficiency. The QD-LED device of Example 3 was aged for 7 days at 70°C with a light intensity of 0.3 W / cm 2 , use an integrating sphere to test the luminous flux and color coordinates, and calculate the luminous efficiency. The measurement results are recorded in Table 1 and Table 2 respectively.

[0124] Table 1

[0125]

[0126] Table 2

[0127]

[0128] By comparing the water permeability and oxygen permeability of the composite materials of Example 1 and Comparative Example 1, and Example 4 and Comparative Example 2, and the degree of change in the luminous efficiency of their light conversion devices before and after aging, it can be found that when the type and proportion of the protective agent contained in the composite material are the same, since a microstructure is formed in the composite material of the embodiment, the protective agent is located in the microstructure, and the content of adverse substances such as water oxygen and free radicals in the microstructure is higher than that in the continuous phase. There is a concentration difference between the two, which will generate osmotic pressure, so that the above-mentioned adverse substances will be preferentially captured by the microstructure after continuing to enter the composite material. Therefore, compared with the composite material of the comparative example without forming a microstructure, the protective agent in the composite material of the embodiment has a higher capture rate of adverse substances, thereby reducing the water permeability and oxygen permeability of the composite material, and also reducing the amount of adverse substances that can contact the quantum dot material, thereby improving the luminescence stability of the quantum dot material.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A composite material, It is characterized in that Comprising a lipophilic continuous phase, a first discontinuous phase and a second discontinuous phase dispersed in the continuous phase, and an emulsifier located at the interface between the first discontinuous phase and the continuous phase, the emulsifier being a water-in-oil surfactant, the first discontinuous phase comprising a plurality of microstructures, the second discontinuous phase comprising an oil-soluble wavelength conversion material, the microstructures comprising a water-soluble protective agent and a dispersion medium for dispersing the protective agent, the protective agent being selected from one or more of the group consisting of a water absorbent, an oxygen scavenger, a radical scavenger and an ultraviolet absorber; the ultraviolet absorber comprises one or more, and the ultraviolet absorber is selected from nano-ZnO, nano-TiO 2 .

2. The composite material according to claim 1, It is characterized in that The microstructure is in liquid, solid or gel state.

3. The composite material according to claim 1, It is characterized in that The control composite material is defined as being different from the composite material only in that the first discontinuous phase and the emulsifier are not included, and the difference between the refractive index of the control composite material and the refractive index of the composite material is within ±0.

5.

4. The composite material according to claim 1, It is characterized in that The dispersion medium includes at least one hydrophilic polymer.

5. The composite material according to claim 4, It is characterized in that The monomers forming the hydrophilic polymer are selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid.

6. The composite material according to any one of claims 1 to 5, It is characterized in that The continuous phase comprises at least one oleophilic polymer.

7. The composite material according to claim 6, It is characterized in that The lipophilic polymer is selected from one or more of polyamide, polyurethane, polylactic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol-lactic acid-glycolic acid copolymer, polyhydroxybutyric acid, polyhydroxyalkyl ester, polybutylene succinate, poly(ethylene glycol terephthalate) and acrylic resin.

8. The composite material according to claim 1, It is characterized in that The water absorbing agent includes one or more, and the water absorbing agent is selected from one or more of ionic liquid, polyvinyl alcohol, sodium sulfate, potassium sulfate, magnesium sulfate, calcium chloride, silica gel and aluminosilicate.

9. The composite material according to claim 1, It is characterized in that The deoxidizer includes one or more, and the deoxidizer is selected from inorganic salt deoxidizer, organic matrix deoxidizer or light-sensitive dye deoxidizer.

10. The composite material according to claim 1, It is characterized in that The oxygen scavenger is selected from one or more of sulfites, enzymes, ascorbic acid, water-soluble photosensitizing dyes and water-soluble singlet oxygen acceptors.

11. The composite material according to claim 1, It is characterized in that The dispersion medium includes at least one organic solvent.

12. The composite material according to claim 11, It is characterized in that The organic solvent is selected from one or more of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran.

13. The composite material according to claim 1, It is characterized in that The dispersion medium includes water as an auxiliary solvent.

14. The composite material according to claim 13, It is characterized in that The solubility of the protective agent in the auxiliary solvent water is recorded as S mg, and the weight ratio between the protective agent and the auxiliary solvent water is (0.85S~S):0.1 or (0.9S~S):0.

1.

15. The composite material according to claim 1, It is characterized in that The weight ratio of the protective agent to the continuous phase is 1:20 to 3:20, and the weight ratio of the protective agent to the wavelength conversion material is 2:1 to 10:

1.

16. A light conversion device, It is characterized in that The composite material comprises the composite material according to any one of claims 1 to 15.

17. The photoconversion device according to claim 16, It is characterized in that The amount of the adverse substance in the continuous phase accounts for 0% to 10% of the total amount of the adverse substances in the photoconversion device, the amount of the adverse substance in the microstructure accounts for 90% to 100% of the total amount of the adverse substances, and the adverse substance is water, oxygen or free radicals.

18. A method for preparing a composite material, It is characterized in that The following steps are involved: S1, mixing and dispersing a raw material of a hydrophilic first discontinuous phase, a raw material of a lipophilic continuous phase, and a water-in-oil surfactant to form a first discontinuous phase dispersed in the raw material of the continuous phase, wherein the first discontinuous phase comprises a plurality of microstructures, wherein the microstructures comprise a water-soluble protective agent and a dispersion medium for dispersing the protective agent, wherein the protective agent is selected from one or more of a water absorbent, a deoxidizer, a free radical scavenger, and a UV absorber; wherein the UV absorber comprises one or more, and the UV absorber is selected from nano ZnO, nano TiO 2 ; S2, mixing and dispersing an oil-soluble wavelength conversion material with the dispersion system obtained in S1 to form a second discontinuous phase dispersed in the raw material of the continuous phase, wherein the second discontinuous phase includes the wavelength conversion material; S3, curing the dispersed system obtained in S2 to obtain the composite material.

19. The preparation method according to claim 18, It is characterized in that In the above S1, the dispersion medium includes at least one hydrophilic monomer or hydrophilic polymer.

20. The preparation method according to claim 19, It is characterized in that The hydrophilic monomer and the monomer forming the hydrophilic polymer are independently selected from one or more of vinyl pyrrolidone, acrylamide and acrylic acid.

21. The preparation method according to claim 18, It is characterized in that The dispersion medium includes at least one organic solvent.

22. The preparation method according to claim 21, It is characterized in that The organic solvent is selected from one or more of ethanol, isopropanol, acetone, acetonitrile, dimethyl sulfoxide, dioxane and tetrahydrofuran.

23. The preparation method according to claim 18, It is characterized in that The dispersion medium includes auxiliary solvent water and a main dispersion medium, and the main dispersion medium is selected from at least one of a water-soluble monomer, a water-soluble polymer and an organic solvent; S1 includes: pre-mixing the protective agent and the auxiliary solvent water to form a mixed liquid, and then mixing and dispersing the mixed liquid with the main dispersion medium and the raw materials of the continuous phase.

24. The preparation method according to claim 23, It is characterized in that The solubility of the protective agent in the auxiliary solvent water is recorded as S mg, and the weight ratio between the protective agent and the auxiliary solvent water is (0.85S~S):0.1 or (0.9S~S):0.

1.

25. The preparation method according to claim 23, It is characterized in that The auxiliary solvent water accounts for 15-20% by weight in the dispersion medium.

26. The preparation method according to claim 18, It is characterized in that The raw material of the continuous phase includes at least one lipophilic monomer or lipophilic polymer.

27. The preparation method according to claim 26, It is characterized in that The lipophilic polymer is selected from one of polyamide, polyurethane, polylactic acid, polylactic acid-glycolic acid copolymer, polyethylene glycol-lactic acid-glycolic acid copolymer, polyhydroxybutyric acid, polyhydroxyalkyl ester, polybutylene succinate, poly(terephthalate) and acrylic resin, and the lipophilic monomer is selected from one or more of the monomers that form the lipophilic polymer.

28. The preparation method according to claim 18, It is characterized in that The weight ratio of the protective agent to the raw material of the continuous phase is 1:20 to 3:20, and the weight ratio of the protective agent to the wavelength conversion material is 2:1 to 10:1.

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