CN114573857B

CN114573857B - Quantum dot lamellar body and preparation method thereof

Info

Publication number: CN114573857B
Application number: CN202210242458.2A
Authority: CN
Inventors: 余世荣; 白俊; 苏昱恺; 康冬冬; 罗飞; 陶真
Original assignee: Najing Technology Corp Ltd
Current assignee: Najing Technology Corp Ltd
Priority date: 2022-03-11
Filing date: 2022-03-11
Publication date: 2023-08-01
Anticipated expiration: 2042-03-11
Also published as: CN114573857A

Abstract

The present disclosure provides a method of preparing a quantum dot layered body, the quantum dot layered body including a quantum dot composite layer, comprising: mixing a plurality of packaging bodies containing quantum dot dispersion liquid and first polymer granules, putting the packaging bodies into first extrusion equipment, heating, melting, extruding, cooling and solidifying, wherein the packaging bodies comprise polymer shells and the quantum dot dispersion liquid positioned in the inner cavities of the shells, the quantum dot dispersion liquid comprises quantum dots and solvents, the heating and melting temperature is higher than the boiling point of the solvents, the solvents volatilize under the heating condition to obtain a quantum dot composite layer, and the heating and melting temperature is higher than the softening temperature of the first polymer granules and lower than the softening temperature of the polymer shells.

Description

Quantum dot lamellar body and preparation method thereof

Technical Field

The disclosure relates to the technical field of quantum dot light conversion plates, in particular to a quantum dot layered body and a preparation method thereof.

Background

The quantum dot light conversion device is used for a backlight assembly in a display field to improve color representation of a display apparatus. The existing mainstream product form is a quantum dot membrane, comprising two barrier films and a quantum dot layer. However, quantum dot membranes still suffer from high cost. Recently, a quantum dot diffusion plate has been proposed, which combines the functions of quantum dots and diffusion plate, has both functions of light diffusion and color conversion, and belongs to an integrated multifunctional plate.

The traditional diffusion plate adopts diffusion particles such as titanium dioxide and silicon dioxide, and achieves the effect of diffusing light through the scattering refraction of the particle surface, but a large number of inorganic particles cannot penetrate light, so that the light transmittance is sacrificed in order to achieve certain haze, and the backlight brightness is greatly reduced.

Recently, a new diffusion plate technology, namely a foaming diffusion plate, is developed, and a large number of 10-1000 micron bubble holes are uniformly distributed in the diffusion plate through chemical/physical foaming, and the diffusion plate has a good light diffusion effect due to the fact that the refractive index of the internal gas is about 1.0 and the refractive index difference between the internal gas and the diffusion plate matrix is large. However, both chemical and physical foaming requires proprietary equipment or extensive modification of existing equipment to accommodate new processes, requires significant investment and poor process suitability, and requires maintenance by specialized technicians.

Disclosure of Invention

The invention aims to provide a quantum dot lamellar body and a preparation method thereof, which simplify the preparation process of the existing foaming quantum dot diffusion plate and improve the light effect of the quantum dot lamellar body.

In order to achieve the above object, according to one aspect of the present disclosure, there is provided a method of preparing a quantum dot layered body including a quantum dot composite layer, including: mixing a plurality of packaging bodies containing quantum dot dispersion liquid and first polymer granules, putting the packaging bodies into first extrusion equipment, heating, melting, extruding, cooling and solidifying, wherein the packaging bodies comprise polymer shells and the quantum dot dispersion liquid positioned in the inner cavities of the shells, the quantum dot dispersion liquid comprises quantum dots and solvents, the heating and melting temperature is higher than the boiling point of the solvents, the solvents volatilize under the heating condition to obtain a quantum dot composite layer, and the heating and melting temperature is higher than the softening temperature of the first polymer granules and lower than the softening temperature of the polymer shells.

Alternatively, the package is spherical and has a diameter of 1-5mm, and the inner cavity of the package has a diameter of 0.05-0.5mm, preferably 0.07-0.15mm.

Alternatively, the glass transition temperature of the polymer shell is greater than 100 ℃, preferably the softening temperature of the polymer shell is greater than 250 ℃.

Optionally, the quantum dot is a water-soluble quantum dot, and the precursor of the polymer shell comprises one or two of a lipophilic prepolymer and a lipophilic monomer, wherein the lipophilic prepolymer is selected from one or more of 3, 5-trimethylcyclohexane methacrylate, divinylbenzene and pentaerythritol tetraacrylate.

Optionally, the quantum dot is an oil-soluble quantum dot, and the precursor of the polymer shell comprises a hydrophilic prepolymer, wherein the hydrophilic prepolymer is selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl methacrylate, ethoxylated trimethylol propane triacrylate, and polyethylene glycol acrylate resin prepolymer.

Optionally, the solvent has a boiling point of less than 200 ℃.

Optionally, when the equivalent quantum dot is a water-soluble quantum dot, the solvent is selected from one or two of water and ethanol; when the quantum dot is an oil-soluble quantum dot, the solvent is selected from one or more of n-hexane, n-octane and toluene.

Optionally, the weight ratio of the encapsulant to the first polymer pellet is 0.02-0.2.

Alternatively, the temperature of the heat fusion is 200-300 ℃.

Optionally, in the extrusion process, a vacuum pumping device is started, so that the processing environment of the raw materials maintains a vacuum degree of-0.05 to-0.1 MPa, and the volatilization of the solvent is accelerated.

Optionally, the polymeric shell comprises a plurality of shell layers, and the outermost layer of the shell is a hydrophobic resin.

Optionally, preparing second polymer pellets, placing the pellets into a second extrusion device, heating and melting, and working together by the first extrusion device and the second extrusion device to obtain a laminated plate of the second polymer layer and the quantum dot composite layer.

Optionally, preparing third polymer granules, putting the third polymer granules into third extrusion equipment, heating and melting, and enabling the third extrusion equipment, the first extrusion equipment and the second extrusion equipment to work together to obtain a laminated plate of the second polymer layer, the quantum dot composite layer and the third polymer layer.

According to two aspects of the present disclosure, there is provided a quantum dot layered body comprising a bubble body dispersed in a polymer matrix, the bubble body comprising bubbles, a polymer shell around the bubbles, and quantum dots located within the bubbles, the bubble body being free of liquid, the polymer matrix having a softening temperature less than the softening temperature of the polymer shell.

Alternatively, the body of the air bubble is spherical and has a diameter of 1-5mm, the diameter of the inner cavity of the air bubble is 0.05-0.5mm, and preferably the diameter of the inner cavity of the air bubble is 0.07-0.15mm.

Optionally, the quantum dot layered body further comprises diffusing particles.

By adopting the technical scheme of the invention, the shell can not be broken in the heating and melting process by controlling the performance of the shell material of the package, so that the quantum dot dispersion liquid does not flow out, the quantum dots are protected from free radical damage generated by the decomposition of the melt of the first polymer granules, and the high efficiency of the quantum dots is maintained. Through volatilizing the solvent in the quantum dot dispersion liquid, the solvent volatilizes to pass through the shell of the packaging body, so that a bubble structure can be formed, a quantum dot lamellar body with bubbles is formed, the refractive index of gas (such as air or other inert gases) of the bubbles is 1, the refractive index difference value between the gas and a polymer matrix formed by the first polymer granules is large, a good scattering effect is formed, and the light mixing uniformity of the quantum dot lamellar body is improved. The preparation process is simple, and the melting and the solvent volatilization can be completed in one step or can be completed successively. Compared with the traditional foaming method, the method does not need to introduce a foaming agent, and has no influence on the stability of the quantum dots.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:

FIG. 1 shows a package with a polymer shell and quantum dot dispersion;

FIG. 2 shows a mixture of encapsulant and first polymer pellets;

FIG. 3 shows a flow chart of a method of preparing a quantum dot composite layer;

FIG. 4 shows a schematic structural diagram of a quantum dot composite layer;

FIG. 5 illustrates a second polymer layer and quantum dot composite layer laminate structure;

fig. 6 shows a laminated structure of a second polymer layer and quantum dot composite layer, a third polymer layer;

fig. 7 shows a stacked structure of a second polymer layer (containing diffusion particles), a quantum dot composite layer, and a third polymer layer (containing diffusion particles);

fig. 8 shows a schematic cross-sectional view of a package of quantum dot dispersion prepared by a droplet photocuring process. Wherein, the reference numerals are as follows:

1. a package; 11. a polymer housing; 12. quantum dot dispersion; 2. a first polymer pellet; 31 bubble bodies; 311. air bubbles; 312. a polymer housing; 32. a polymer matrix; 3. a quantum dot composite layer; 4. a second polymer layer; 5. a third polymer layer; 6. and diffusing the particles.

For ease of understanding, the positions, dimensions, ranges, etc. of the respective structures shown in the drawings and the like may not represent actual positions, dimensions, ranges, etc. Accordingly, the present disclosure is not limited to the disclosed positions, dimensions, ranges, etc. as illustrated in the accompanying drawings.

Detailed Description

Various exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. That is, the structures and methods herein are shown by way of example to illustrate different embodiments of the structures and methods in this disclosure. However, those skilled in the art will appreciate that they are merely illustrative of the exemplary ways in which the disclosure may be practiced, and not exhaustive. Moreover, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components.

In addition, techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.

The words "left", "right", "front", "back", "top", "bottom", "upper", "lower", "high", "low", and the like in the description and in the claims, if present, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the disclosure described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. For example, when the device in the figures is inverted, features that were originally described as "above" other features may be described as "below" the other features. The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the relative spatial relationship will be explained accordingly.

In the description and claims, an element is referred to as being "on," attached "to," connected "to," coupled "to," etc., another element, which may be directly on, attached to, coupled to, or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly on," "directly attached to," directly connected to, "directly coupled" to, or "directly coupled" to another element, there are no intervening elements present. In the description and claims, a feature being disposed "adjacent" to another feature may refer to a feature having a portion that overlaps with, or is located above or below, the adjacent feature.

As used herein, the word "exemplary" means "serving as an example, instance, or illustration," and not as a "model" to be replicated accurately. Any implementation described herein by way of example is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, this disclosure is not limited by any expressed or implied theory presented in the technical field, background, brief summary or the detailed description.

In addition, for reference purposes only, the terms "first," "second," and the like may also be used herein, and are thus not intended to be limiting. For example, the terms "first," "second," and other such numerical terms referring to structures or elements do not imply a sequence or order unless clearly indicated by the context.

It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components, and/or groups thereof.

In this disclosure, the term "providing" is used in a broad sense to cover all ways of obtaining an object, and thus "providing an object" includes, but is not limited to, "purchasing," "preparing/manufacturing," "arranging/setting," "installing/assembling," and/or "ordering" an object, etc.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

According to a first aspect of the present disclosure, there is provided a method of preparing a quantum dot laminate, the quantum dot laminate comprising a quantum dot composite layer, comprising: mixing a plurality of packaging bodies containing quantum dot dispersion liquid and first polymer granules, putting the packaging bodies into first extrusion equipment, heating, melting, extruding, cooling and solidifying, wherein the packaging bodies comprise polymer shells and the quantum dot dispersion liquid positioned in the inner cavities of the shells, the quantum dot dispersion liquid comprises quantum dots and solvents, the heating and melting temperature is higher than the boiling point of the solvents, the solvents volatilize under the heating condition to obtain a quantum dot composite layer, and the heating and melting temperature is higher than the softening temperature of the first polymer granules and lower than the softening temperature of the polymer shells.

The package as a raw material is shown in fig. 1, and includes a quantum dot dispersion liquid and a polymer shell. As shown in fig. 2, the encapsulant and the first polymer pellets are mixed. Fig. 3 illustrates a method of preparing a quantum dot composite layer of a quantum dot layered body. Fig. 4 shows a cross-sectional structure of a quantum dot composite layer, the bubble body 31 comprising a bubble 311 and a polymer shell 312, wherein quantum dots located within the bubble body are not numbered. By controlling the performance of the shell material of the packaging body, the shell is not broken in the heating and melting process, so that the quantum dot dispersion liquid does not flow out, the quantum dots are protected from free radical damage generated by the decomposition of the melt of the first polymer granules, and the high efficiency of the quantum dots is maintained. Through volatilizing the solvent in the quantum dot dispersion liquid, the solvent volatilizes to pass through the shell of the packaging body, so that a bubble structure can be formed, a quantum dot lamellar body with bubbles is formed, the refractive index of gas (such as air or other inert gases) of the bubbles is 1, the refractive index difference value between the gas and a polymer matrix formed by the first polymer granules is large, a good scattering effect is formed, and the light mixing uniformity of the quantum dot lamellar body is improved. The solvent is volatilized in the heating and melting step, for example, the volatilization is incomplete in the heating and melting step, and the solvent can be further volatilized by heating after cooling and solidifying. The preparation process is simple, and the melting and the solvent volatilization can be completed in one step or can be completed successively. Compared with the traditional foaming method, the method does not need to introduce a foaming agent, and has no influence on the stability of the quantum dots.

The quantum dot dispersion includes red quantum dots and/or green quantum dots. In some embodiments, the package body only comprises red quantum dots or green quantum dots, and by mixing the red package body and the green package body, the influence among different quantum dots is reduced, the red-green quantum dot layered body is formed, and white light emission is realized under the excitation of an external light source such as blue light.

The package body with the solid outside and the liquid inside can be any shape as long as the process can be realized. In some embodiments, the package is spherical and has a diameter of 1-5mm, and the package has a lumen diameter of 0.05-0.5mm, preferably 0.07-0.15mm. The diameter of the package body can be selected according to the total thickness of the quantum dot layered body, the sizes of the multiple package bodies are not required to be completely consistent, the diameter of the inner cavity of the package body can be selected in combination with the size of the required bubble, and the diameter of the inner cavity of the package body is not required to be completely consistent. Preferably, the packages are uniform in size, which is advantageous for estimating the quantum dot content within the package.

The first polymer pellet may be approximately the size of the package, e.g., 1-5mm in any one dimension. The first polymer pellets are selected from one or more of PMMA (polymethyl methacrylate), PS (polystyrene), PC (polycarbonate), PP (polypropylene) or their corresponding copolymers.

In some embodiments, the glass transition temperature of the polymer shell is greater than 100 ℃, preferably the softening temperature of the polymer shell is greater than 250 ℃. The highly crosslinked polymeric materials are generally selected to meet the above-mentioned needs.

According to the selection of the preparation process of the encapsulation body, the encapsulation body can be obtained by solidifying after the W/O/W emulsion is coated to form the liquid beads, in some embodiments, the quantum dots are water-soluble quantum dots, the precursor of the polymer shell comprises one or two of lipophilic prepolymer and lipophilic monomer, and the lipophilic prepolymer is selected from one or more of 3, 5-trimethylcyclohexane methacrylate, divinylbenzene and pentaerythritol tetraacrylate.

Depending on the choice of the encapsulation preparation process, the encapsulation may be obtained by coating the O/W/O emulsion to form beads and then curing the beads, and in some embodiments the quantum dots are oil-soluble quantum dots, and the precursor of the polymer shell comprises a hydrophilic prepolymer selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl methacrylate, ethoxylated trimethylol propane triacrylate, and polyethylene glycol acrylate resin prepolymers.

Preferably, the quantum dots within the package are oil soluble quantum dots and the polymer shell is also a hydrophobic polymer, thereby allowing for longer lifetime of the quantum dots. The process implementation of this structure is, for example, to make a hollow polymer body, to which the quantum dot dispersion is injected with a needle tip and then encapsulated with a polymer, but is not limited thereto.

In some embodiments, the solvent has a boiling point of less than 200 ℃. Thereby volatilizing the solvent at a lower temperature.

In some embodiments, when the quantum dots are water-soluble quantum dots, the solvent is selected from one or both of water, ethanol; when the quantum dot is an oil-soluble quantum dot, the solvent is selected from one or more of n-hexane, n-octane and toluene. The conversion of the water solubility and the oil solubility of the quantum dots can be obtained according to the conventional technology in the field.

In some embodiments, the weight ratio of the encapsulant to the first polymer pellet is 0.02-0.2. Thereby controlling the distribution density of the formed bubbles in the first polymer. Preferably, the weight ratio of the encapsulant to the first polymer pellet is 0.1.

The quantum dots in the quantum dot dispersion liquid account for 1-2wt% of the weight of the packaging body.

In some embodiments, the temperature of the heat fusion is 200-300 ℃. The temperature of the heat fusion is selected primarily based on the softening temperature of the polymer pellets to effect fusion of the first polymer.

In some embodiments, during the extrusion process, the vacuum extractor is turned on so that the processing environment of the raw materials maintains a vacuum level of-0.05 to-0.1 MPa, accelerating the volatilization of the solvent.

In some embodiments, the polymeric shell comprises a plurality of shell layers, with the outermost layer of the shell being a hydrophobic resin. The hydrophobic resin can prevent moisture from entering the bubble body and protect the quantum dots.

The quantum dot layered body may be one or more layers, and the quantum dot layered body as a product may be separated from the boundary between layers due to fusion between layers or the like. The thickness of the quantum dot layered body may be any thickness, and may be referred to as a quantum dot film when thin and as a quantum dot plate when thick.

The processes of the layers of the quantum dot layered body may be different from each other, for example, a new layer may be formed by coating, spraying, etc. on the surface of the quantum dot composite layer, instead of using a melt extrusion method.

In some embodiments, the second polymer pellets are prepared and placed in a second extrusion device for heating to melt, and the first extrusion device and the second extrusion device work together to produce a sheet of a laminate of the second polymer layer and the quantum dot composite layer. The resulting structure is shown in FIG. 5.

In some embodiments, a third polymer pellet is prepared and placed in a third extrusion device to be heated and melted, and the third extrusion device works together with the first extrusion device and the second extrusion device to obtain a laminated plate of the second polymer layer, the quantum dot composite layer and the third polymer layer. The resulting structure is shown in FIG. 6.

Auxiliaries may be added during the preparation of the second polymer layer from the second polymer pellets and/or during the preparation of the third polymer layer from the third polymer pellets. Such as one or more of a diffusing agent/particle, an ultraviolet absorber/particle, a whitening agent, an anti-yellowing agent and other formulas or functional additives, and is extruded into a thin layer in a mold after melting to improve haze or concealing property.

According to a second aspect of the present disclosure there is provided a quantum dot layered body comprising a body of gas bubbles dispersed in a polymer matrix, the body of gas bubbles comprising gas bubbles, a polymer shell around the gas bubbles and quantum dots located within the gas bubbles, the body of gas bubbles being free of liquid, the polymer matrix having a softening temperature less than the softening temperature of the polymer shell. The quantum dot layered body has the effects of light weight, high quantum dot light efficiency and uniform emergent light, and can be used in backlight display and illumination products.

In some embodiments, the body of the bubbles is spherical and has a diameter of 1-5mm, the lumen diameter of the bubbles is 0.05-0.5mm, and preferably the lumen diameter of the bubbles is 0.07-0.15mm.

In some embodiments, the glass transition temperature of the polymer shell is greater than 100 ℃, preferably the softening temperature of the polymer shell is greater than 250 ℃.

In some embodiments, the quantum dots are water-soluble quantum dots, and the precursor of the polymer shell comprises one or two of a lipophilic prepolymer and a lipophilic monomer, wherein the lipophilic prepolymer is selected from one or more of 3, 5-trimethylcyclohexane methacrylate, divinylbenzene and pentaerythritol tetraacrylate.

In some embodiments, the quantum dots are oil-soluble quantum dots, and the precursor of the polymer shell comprises a hydrophilic prepolymer selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl methacrylate, ethoxylated trimethylol propane triacrylate, and polyethylene glycol based acrylate resin prepolymers.

In some embodiments, the quantum dot layered body further comprises diffusing particles. The diffusion particles and the quantum dots can be positioned on the same layer, and the diffusion particles and the gas cooperate to enable the emergent light of the two-character-point layered body to be more uniform in the working state.

In some embodiments, the quantum dot layered body comprises a three-layer structure with undefined boundaries between layers, including a first diffusion layer, a quantum dot composite layer, and a second diffusion layer that are sequentially adjacent. The structure is shown in fig. 7. In some embodiments, the diffusion layer surface has a raised structure, which is a prismatic layer or a frosted layer.

Hereinafter, the embodiments are described in more detail with reference to specific examples. However, they are illustrative examples of the present disclosure, and the present disclosure is not limited thereto.

Example 1

Preparing a packaging body of quantum dot dispersion liquid by adopting a microfluidic pipeline method (W1/O/W2), wherein an external dispersion phase W1 (water phase) adopts deionized water, and 10 weight percent of sodium dodecyl sulfate and 10 weight percent of polyvinyl alcohol are added as a surfactant; the middle oil phase O is the shell precursor of the packaging body, which adopts 3, 5-trimethylcyclohexane methacrylate (39 wt%), divinylbenzene (30 wt%), pentaerythritol tetraacrylate (10 wt%), resin prepolymer-saruma CN9006 NS (20 wt%), photoinitiator TPOL (1 wt%), an internal quantum dot liquid phase W2 (water phase) adopts a quantum dot water solution, and the content of water-soluble CdSe quantum dots is 5wt%. Referring to fig. 8, a package was prepared by photo (L) curing after droplet discharge through a three-phase microfluidic channel, and the photo curing system energy was set at 2000mJ. The package body is spherical, the diameter is 2mm, and the internal diameter is 1mm. The softening temperature of the polymer shell of the encapsulant is about 350 ℃.

Mixing 10wt% of Polystyrene (PS) matrix resin granules (90 wt%) with the prepared packaging body, extruding the packaging body through an existing diffusion plate extruder, wherein the melting temperature is 210 ℃, the vacuum degree of the middle section is maintained at-0.06 Mpa to-0.1 Mpa, and then, cooling and pulling the packaging body to a plate cutting machine to cut the packaging body to obtain the quantum dot diffusion plate with the bubble body.

Example 2

The difference from example 1 is that the encapsulation was prepared using an O1/W/O2 system, the external disperse phase O1 (oil phase) was n-octane, and 15wt% fatty alcohol-polyoxyethylene ether carboxylate surfactant was added; the middle water phase W, namely the shell precursor of the packaging body, adopts hydrophilic prepolymer such as acrylic acid (9 wt%), methacrylic acid (20 wt%), hydroxyethyl methacrylate (30 wt%), ethoxylated trimethylol propane triacrylate (10 wt%), polyethylene glycol (400) dimethacrylate (20 wt%), polyethylene glycol (600) diacrylate) (10 wt%) and the like, and a photoinitiator TPOL (1 wt%). The internal quantum dot liquid phase O2 (oil phase) adopts quantum dot n-octane solution, and the content of the oil-soluble CdSe quantum dots is 5wt%. The package body is spherical, the diameter is 2mm, and the internal diameter is 1mm. The softening temperature of the polymer shell of the package is about 300 ℃.

The process for producing the quantum dot diffusion plate is the same as that of example 1.

Comparative example 1

First quantum dot master batch. The quantum dot master batch is produced by adopting a mode that oil-soluble quantum dot CdSe-series n-octane solution is mixed with PS matrix resin granules (namely polymer granules) and the mixture is pumped by a plastic granulator, wherein the concentration of the quantum dots is 5 weight percent. The oil-soluble quantum dot species were the same as in example 2.

Then mixing quantum dot master batch (10 wt%) and dispersing agent master batch (5 wt%) with PS matrix resin granules (85 wt%) and extruding the dispersing plate by means of existent dispersing plate extruder, its melting temperature is 210 deg.C, and making it pass through the processes of press roll and cooling, and making it be drawn into plate cutting machine so as to obtain the invented common quantum dot dispersing plate.

Comparative example 2

The difference from comparative example 1 is that in the second step, azodicarbonamide blowing agent (5 wt%) was added and a special foaming diffusion plate line was used to produce a foaming quantum dot diffusion plate.

The diffusion plates of the respective examples and comparative examples have the same thickness. In the haze test, a 450nm blue LED lamp is used as a backlight spectrum, a quantum dot diffusion plate is placed on a sample stage, the spectrum of a blue backlight light source and the spectrum of a transmitted quantum dot diffusion plate are respectively tested by using an integrating sphere, and the light conversion efficiency is calculated by using the integral area of the spectrogram. Light conversion efficiency = number of emitted photons/number of absorbed photons = (peak area of quantum dot diffusion plate fluorescence emission spectrum)/(peak area of blue backlight-peak area of blue backlight not absorbed through quantum dot diffusion plate) ×100%. The test results of the respective examples and comparative examples are shown in table 1:

TABLE 1

Project	Haze degree	Light conversion efficiency
			Example 1	95％	45％
Example 2	96％	55％
			Comparative example 1	91％	30％
Comparative example 2	97％	25％

As shown in table 1, the quantum dot diffusion plates of examples 1 and 2 were superior to the conventional non-foaming quantum dot diffusion plate and the conventional foaming quantum dot diffusion plate in both haze and quantum efficiency.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. The embodiments disclosed herein may be combined in any desired manner without departing from the spirit and scope of the present disclosure. Those skilled in the art will also appreciate that various modifications might be made to the embodiments without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A method of preparing a quantum dot layered body comprising a quantum dot composite layer, comprising:

mixing a plurality of packaging bodies containing quantum dot dispersion liquid and first polymer granules, putting the packaging bodies into first extrusion equipment, heating, melting, extruding, cooling and solidifying, wherein the packaging bodies comprise polymer shells and the quantum dot dispersion liquid positioned in shell inner cavities, the quantum dot dispersion liquid comprises quantum dots and a solvent, the heating and melting temperature is higher than the boiling point of the solvent, the solvent is volatilized under the heating condition, and the quantum dot composite layer is obtained, and the heating and melting temperature is higher than the softening temperature of the first polymer granules and lower than the softening temperature of the polymer shells.

2. The method of claim 1, wherein the package is spherical and has a diameter of 1-5mm, and the inner cavity of the package has a diameter of 0.05-0.5mm.

3. The method of claim 2, wherein the lumen diameter is 0.07-0.15mm.

4. The method of claim 1, wherein the polymer shell has a softening temperature greater than 100 ℃.

5. The method of claim 4, wherein the polymer shell has a softening temperature greater than 250 ℃.

6. The method of claim 1, wherein the quantum dots are water-soluble quantum dots, and the precursor of the polymer shell comprises one or two of a lipophilic prepolymer and a lipophilic monomer, and the lipophilic prepolymer is one or more selected from 3, 5-trimethylcyclohexane methacrylate, divinylbenzene and pentaerythritol tetraacrylate.

7. The method of claim 1, wherein the quantum dots are oil-soluble quantum dots, and the precursor of the polymer shell comprises a hydrophilic prepolymer selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl methacrylate, ethoxylated trimethylol propane triacrylate, and polyethylene glycol based acrylate resin prepolymers.

8. The method of claim 1, wherein the solvent has a boiling point of less than 200 ℃.

9. The method of claim 1, wherein when the quantum dots are water-soluble quantum dots, the solvent is selected from one or both of water and ethanol; when the quantum dot is an oil-soluble quantum dot, the solvent is selected from one or more of n-hexane, n-octane and toluene.

10. The method of claim 1, wherein the weight ratio of the encapsulant to the first polymer pellet is 0.02-0.2.

11. The method of claim 1, wherein the temperature of the heat fusion is 200-300 ℃.

12. The method according to claim 1, wherein in the extrusion process, a vacuum-pumping device is turned on so that the processing environment of the raw material is maintained at a vacuum level of-0.05 to-0.1 MPa, and volatilization of the solvent is accelerated.

13. The method of claim 1, wherein the polymeric shell comprises a plurality of shell layers, and wherein the outermost layer of the shell is a hydrophobic resin.

14. The method of claim 1, wherein the second polymer pellets are prepared and placed in a second extrusion device for heating and melting, and wherein the first extrusion device and the second extrusion device work together to provide a laminate of the second polymer layer and the quantum dot composite layer.

15. The method of claim 14, wherein the third polymer pellets are prepared and placed in a third extrusion device, and the third extrusion device, the first extrusion device and the second extrusion device work together to obtain a laminate of the second polymer layer, the quantum dot composite layer and the third polymer layer.

16. A layered body of quantum dots, comprising a body of bubbles dispersed in a polymer matrix, the body of bubbles comprising bubbles, a polymer shell around the bubbles, and quantum dots within the bubbles, the body of bubbles being free of liquid, the polymer matrix having a softening temperature less than the softening temperature of the polymer shell.

17. The quantum dot layered body of claim 16, wherein the bubble body is spherical and has a diameter of 1-5mm, and the inner cavity diameter of the bubble is 0.05-0.5mm.

18. The quantum dot laminate according to claim 17, wherein the inner cavity diameter of the bubbles is 0.07-0.15mm.

19. The quantum dot laminate of claim 16, wherein the polymer shell has a softening temperature greater than 100 ℃.

20. The quantum dot laminate of claim 19, wherein the polymer shell has a softening temperature greater than 250 ℃.

21. The quantum dot laminate according to claim 16, wherein the quantum dot is a water-soluble quantum dot, and the precursor of the polymer shell comprises one or two of a lipophilic prepolymer and a lipophilic monomer, and the lipophilic prepolymer is one or more selected from 3, 5-trimethylcyclohexane methacrylate, divinylbenzene, pentaerythritol tetraacrylate.

22. The quantum dot laminate of claim 16, wherein the quantum dot is an oil-soluble quantum dot and the precursor of the polymer shell comprises a hydrophilic prepolymer selected from one or more of acrylic acid, methacrylic acid, hydroxyethyl methacrylate, ethoxylated trimethylol propane triacrylate, and polyethylene glycol based acrylate resin prepolymers.

23. The quantum dot laminate of claim 16, wherein the quantum dot laminate further comprises diffusing particles.