A coated reflective film containing white light quantum dot coated organic particles and a preparation method thereof

Abstract

The present application relates to the technical field of optical reflection film, disclose a kind of coating reflection film containing white light quantum dot coated organic particle and preparation method, including white reflection base film and coating in the surface of white reflection base film;The raw materials in the coating include white light quantum dot coated organic particle, adhesive and auxiliary agent;White light quantum dot coated organic particle, white light quantum dot is the ZnCuGaInS / ZnS quantum dot after surface ligand exchange by containing thiol functional group molecule, and the particle size of organic particle is 3~50 μm.The white light quantum dot coated organic particle is used as coating particle in the coating of the present application, since the coating contains organic flexible particle, therefore, the coating reflection film provided by the present application has good anti-absorption effect;In addition, since the surface of coating particle is coated with white light quantum dot, the material can spontaneously generate white light emission under the excitation of backlight, greatly increase the brightness of coating reflection film.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical reflection film, in particular to a coated reflection film containing white light quantum dot coated organic particles and a preparation method thereof. BACKGROUND

[0002] The reflection film is an important component in the display backlight module, and its main function is to reflect the light emitted downward in the light source back to the upper part of the backlight module for light compensation, so its reflection ability of light plays a decisive role in the overall brightness of the display. With the development of large-size display, consumers' demand for the brightness of the display is increasingly improved. The assembly of large-size display is usually accompanied by the adsorption problem between the bottom reflection film and the light guide plate. The commonly used solution is to coat particles on the surface of the reflection film to form an air barrier layer between the reflection sheet and the light guide plate, thereby avoiding adsorption. However, coating will inevitably cause the brightness loss of the reflection sheet, resulting in poor performance in large-size display, so improving the brightness of the coated reflection sheet has become an important topic in the field of large-size display.

[0003] The patent with publication number CN114637061A discloses a high-toughness high-brightness reflection film and a preparation method thereof, and the core technology is to coat a glue layer containing quantum dot materials on the surface of the reflection film, and to achieve the purpose of improving the brightness through the optical gain generated by the quantum confinement effect of the quantum dot materials.

[0004] However, the quantum dot materials used in this patent are inorganic particles such as silicon dioxide, titanium dioxide, ferric oxide or copper oxide. On the one hand, these materials are rigid particles, which can easily scratch the light guide plate made of soft material during assembly. Moreover, due to the nanoscale size of the materials, it is difficult to form an air barrier layer between the reflection film and the light guide plate, so the anti-adsorption effect is not ideal. On the other hand, these particles do not have the characteristic of self-luminescence, so the brightness improvement effect of the coated reflection film is not significant. SUMMARY

[0005] The present application is to overcome the problem of brightness loss of the reflection film itself caused by coating particles on the surface of the reflection film in the prior art, and to provide a coated reflection film containing white light quantum dot coated organic particles and a preparation method thereof. In the coating layer, white light quantum dot coated organic particles are used as coating particles. Since the coating layer contains organic flexible particles, the coated reflection film provided by the present application has good anti-adsorption effect. In addition, since the surface of the coating particles is coated with white light quantum dots, the material can spontaneously emit white light under the excitation of the backlight source, greatly increasing the brightness of the coated reflection film.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A coated reflective film containing white quantum dot-coated organic particles includes a white reflective base film and a coating layer coated on the surface of the white reflective base film; the raw materials in the coating layer include white quantum dot-coated organic particles, adhesives, and additives.

[0008] The organic particles are coated with white light quantum dots. The white light quantum dots are ZnCuGaInS / ZnS quantum dots after surface ligand exchange through molecules containing thiol functional groups. The organic particles are one or more of PMMA particles, PBMA particles, PET particles, and PA particles, and the particle size of the organic particles is 3~50μm.

[0009] This invention incorporates white quantum dot-coated organic particles as coating particles into the coating of the reflective film. The larger organic particles can form protrusions in the coating. The organic particles are relatively soft and can provide a certain buffering effect when the backlight module is subjected to external pressure, preventing the bottom reflective sheet from scratching the light guide plate and causing white spots on the display. In addition, these protruding coating particles have a supporting function, ensuring that an air barrier layer can be formed between the bottom reflective film and the upper light guide plate, avoiding direct contact between the light guide plate and the adhesive coating, which would cause adhesion and result in dark shadows on the display.

[0010] Meanwhile, this invention coats the surface of organic particles with white quantum dots, and these ZnCuGaInS / ZnS quantum dots can emit white fluorescence across the entire visible light spectrum. When the coated reflective film provided by this invention is applied to a backlight module, the white quantum dots on the surface of the coated particles emit white light under the excitation of the backlight source, which is equivalent to introducing a second light source into the backlight. This increases the amount of light returning from the bottom reflective film to the upper light guide plate, thereby improving the brightness of the coated reflective sheet. Since the ZnCuGaInS / ZnS quantum dots produce fluorescence emission across the entire visible light spectrum, the coated reflective sheet provided by this invention has light gain in the blue, green, and red light bands, resulting in a good brightness enhancement effect.

[0011] This invention utilizes surface ligand exchange, replacing the original oleic acid and oleylamine ligands on the surface of white quantum dots with molecules containing thiol functional groups. Due to the greater electronegativity of thiol functional groups, they can form stronger coordination bonds with the quantum dot surface. Simultaneously, under the action of photoinitiators and UV light, thiol functional groups generate sulfur radicals. These sulfur radicals can cross-link with the unsaturated bonds in organic particle molecules through click reactions, ensuring that the white quantum dots are firmly coated onto the surface of the organic coated particles. Compared to methods that directly mechanically mix white quantum dots with organic coated particles, the method provided by this invention ensures that the white quantum dots are uniformly dispersed in the coating liquid along with the organic coated particles, avoiding aggregation or sedimentation of white quantum dots dispersed alone in the coating liquid. Furthermore, the organic coated particles coated with white quantum dots are embedded in an adhesive coating, which also acts as a water and oxygen barrier layer to protect the quantum dots, improving the luminescence stability of the white quantum dots.

[0012] Preferably, in the white quantum dot-coated organic particles, the mass ratio of white quantum dots to organic particles is 1:14~25. If the number of white quantum dots coated on the surface of the organic particles is too small, the light compensation provided by the excited white quantum dots will be insufficient, resulting in an unsatisfactory brightness enhancement effect of the coated reflective film. Conversely, due to the self-absorption phenomenon of white quantum dots, if the quantum dots distributed too densely on the surface of the organic particles, the fluorescence generated by some quantum dots after excitation will be absorbed by other quantum dots, which will also affect the brightness enhancement effect of the coated reflective film.

[0013] Preferably, the molecule containing the thiol functional group is pentaerythritol tetramercaptoacetate and / or γ-mercaptopropyltrimethoxysilane; during surface ligand exchange, the mass ratio of ZnCuGaInS / ZnS quantum dots to the molecule containing the thiol functional group is 1:30~50.

[0014] Preferably, the raw materials in the coating, by weight, include: 3-8 parts of white quantum dot-coated organic particles, 75-85 parts of adhesive, and 8-12 parts of additives; the refractive index of the adhesive is 1.43-1.53. Adhesives with refractive indices within this range have good photosynthetic affinity and will not affect the luminescence properties of the quantum dots.

[0015] Preferably, the adhesive is one of thermosetting acrylic adhesive, polyurethane resin, epoxy resin, and polyvinyl acetal resin; the additive is at least one of dispersant, curing agent, and antistatic agent.

[0016] Preferably, in the coating, the amount of white quantum dots coated with organic particles is 1.5~2.5 g / m². 2 .

[0017] Preferably, the white reflective base film has a reflectivity >95%; the white reflective base film is one of foamed polyethylene terephthalate base film, polypropylene base film, and polycarbonate base film.

[0018] Preferably, the thickness of the white reflective base film is 100~188μm.

[0019] The present invention also provides a method for preparing the above-mentioned coating reflective film containing white light quantum dots coated with organic particles, comprising the following steps:

[0020] (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion;

[0021] (2) Quantum dot surface ligand exchange: ZnCuGaInS / ZnS quantum dot dispersion and molecular solution containing thiol functional groups were mixed and stirred to obtain white light quantum dot dispersion after surface ligand exchange.

[0022] (3) Coating organic particles: The white quantum dot dispersion after surface ligand exchange is added to the dispersion of organic particles, and a photoinitiator is added. After stirring and drying under ultraviolet irradiation, a white quantum dot-coated organic particle dispersion is obtained.

[0023] (4) Preparation of coating solution: Add the raw materials in the coating to the organic solvent and mix evenly to prepare the coating solution;

[0024] (5) Coating: The coating liquid is applied to the surface of the white reflective base film and cured to obtain the coated reflective film containing white light quantum dots coated with organic particles.

[0025] Preferably, in step (2), the reaction is stirred under a protective atmosphere, the stirring speed is 800~1500 rpm, and the reaction time is 4~5 h.

[0026] Preferably, the photoinitiator in step (3) is dimethylphenylphosphine or TPO; step (3) is performed at 180~200W / m 2 The reaction was carried out under ultraviolet irradiation and stirring at 400-600 rpm for 2-3 hours.

[0027] Preferably, the organic solvent in the coating solution in step (4) is a mixed solvent of ethyl acetate and butyl acetate in a volume ratio of 1:0.5~2.

[0028] Preferably, in the coating liquid of step (4), the mass ratio of adhesive to organic solvent is 1:2~3.

[0029] Preferably, the curing temperature in step (5) is 90~120℃ and the curing time is 2~4min.

[0030] Therefore, the present invention has the following beneficial effects:

[0031] (1) Add white quantum dots to the coating to coat organic particles as coating particles; the organic particles have a larger particle size and a softer material, which can prevent the bottom reflective film from scratching the light guide plate and causing white spots on the display; and can ensure that an air barrier layer can be formed between the bottom reflective film and the upper light guide plate, avoiding the light guide plate from directly contacting the adhesive coating and causing adhesion and resulting in shadows on the display.

[0032] (2) The white quantum dots coated on the surface of organic particles can emit white fluorescence in the entire visible light band. When excited by the backlight, they will emit white light, which is equivalent to introducing a second light source into the backlight, thereby increasing the amount of light returning from the bottom reflective film to the upper light guide plate, thus achieving the effect of improving the brightness of the coated reflective sheet.

[0033] (3) Through surface ligand exchange, molecules containing thiol functional groups replace the original oleic acid and oleylamine ligands on the surface of white quantum dots. The thiol functional groups generate sulfur free radicals under the action of photoinitiators and UV. These sulfur free radicals can crosslink with the unsaturated bonds in organic particle molecules through click reactions, ensuring that white quantum dots can be firmly coated on the surface of organic coated particles. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments.

[0035] In this invention, unless otherwise specified, all equipment and raw materials are available from the market or commonly used in the industry. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0036] General Implementation Examples:

[0037] A coated reflective film containing white quantum dot-coated organic particles includes a white reflective base film and a coating layer coated on the surface of the white reflective base film; the raw materials in the coating layer include white quantum dot-coated organic particles, adhesives, and additives.

[0038] The organic particles are coated with white light quantum dots. The white light quantum dots are ZnCuGaInS / ZnS quantum dots after surface ligand exchange through molecules containing thiol functional groups. The organic particles are one or more of PMMA particles, PBMA particles, PET particles, and PA particles, and the particle size of the organic particles is 3~50μm.

[0039] In one specific implementation, the mass ratio of white quantum dots to organic particles in the white quantum dot-coated organic particles is 1:14~25.

[0040] In one specific embodiment, the molecule containing the thiol functional group is pentaerythritol tetramercaptoacetate and / or γ-mercaptopropyltrimethoxysilane; during surface ligand exchange, the mass ratio of ZnCuGaInS / ZnS quantum dots to the molecule containing the thiol functional group is 1:30~50.

[0041] In one specific embodiment, the raw materials in the coating, by weight, include: 3-8 parts of white light quantum dot-coated organic particles, 75-85 parts of adhesive, and 8-12 parts of additives; the refractive index of the adhesive is 1.43-1.53.

[0042] In one specific embodiment, the adhesive is one of thermosetting acrylic adhesive, polyurethane resin, epoxy resin, and polyvinyl acetal resin; the additive is at least one of dispersant, curing agent, and antistatic agent.

[0043] In one specific embodiment, the coating amount of white quantum dots coated with organic particles is 1.5~2.5 g / m². 2 .

[0044] In one specific embodiment, the white reflective base film has a reflectivity >95%; the white reflective base film is one of foamed polyethylene terephthalate base film, polypropylene base film, and polycarbonate base film.

[0045] In one specific implementation, the thickness of the white reflective base film is 100~188μm.

[0046] The preparation method of the above-mentioned coating reflective film containing white light quantum dots coated with organic particles includes the following steps:

[0047] (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion;

[0048] (2) Quantum dot surface ligand exchange: ZnCuGaInS / ZnS quantum dot dispersion and molecular solution containing thiol functional groups were mixed and stirred to obtain white light quantum dot dispersion after surface ligand exchange.

[0049] (3) Coating organic particles: The white quantum dot dispersion after surface ligand exchange is added to the dispersion of organic particles, and a photoinitiator is added. After stirring and reacting under ultraviolet irradiation and drying, white quantum dot coated organic particles are obtained.

[0050] (4) Preparation of coating solution: Add the raw materials in the coating to the organic solvent and mix evenly to prepare the coating solution;

[0051] (5) Coating: The coating liquid is applied to the surface of the white reflective base film and cured to obtain the coated reflective film containing white light quantum dots coated with organic particles.

[0052] As a specific implementation method, in step (1), ZnCuGaInS / ZnS quantum dot dispersion is prepared by referring to the method in patent CN117285930A.

[0053] In one specific implementation, in step (2), the reaction is stirred under a protective atmosphere, the stirring speed is 800~1500 rpm, and the reaction time is 4~5h.

[0054] In one specific embodiment, the photoinitiator mentioned in step (3) is dimethylphenylphosphine or TPO; step (3) is performed at 180~200W / m 2 The reaction was carried out under ultraviolet irradiation and stirring at 400-600 rpm for 2-3 hours.

[0055] In one specific embodiment, the organic solvent in the coating liquid in step (4) is a mixed solvent of ethyl acetate and butyl acetate in a volume ratio of 1:0.5~2.

[0056] In one specific implementation, the mass ratio of adhesive to organic solvent in the coating liquid of step (4) is 1:2~3.

[0057] In one specific implementation, the curing temperature in step (5) is 90~120℃ and the curing time is 2~4min.

[0058] Example 1:

[0059] A coated reflective film containing white quantum dot-coated organic particles includes a 150 μm thick white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150, reflectivity 96.8%) and a coating layer applied to the surface of the white reflective base film; by weight, the raw materials in the coating layer include 6.3 parts white quantum dot-coated organic particles, 82 parts thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts curing agent, 0.7 parts antistatic agent and 3 parts dispersant BYK-156.

[0060] The preparation method of the above-mentioned coating reflective film containing white light quantum dots coated with organic particles includes the following steps:

[0061] (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion:

[0062] a) Dissolve zinc acetate in octadecene and n-dodecyl mercaptan at 150°C with stirring, using the solution as zinc precursor solution No. 1, with a concentration of 0.5 mol / L.

[0063] b) Dissolve zinc carbonate at 170°C by stirring in a mixed solution of octadecene, n-dodecyl mercaptan and oleic acid in a volume ratio of 1:1:2, as zinc precursor solution No. 2, with a precursor solution concentration of 0.5 mol / L.

[0064] c) Weigh a certain mass of zinc stearate and dissolve it in octadecene and n-dodecyl mercaptan at 200℃ with stirring. This solution is prepared as zinc precursor solution No. 3 and has a concentration of 0.5 mol / L.

[0065] d) Add zinc iodide, cuprous iodide, gallium iodide, elemental sulfur, indium iodide, and oleylamine and n-dodecyl mercaptan in a molar ratio of 1:0.04:0.3:0.6:0.03 to a three-necked flask. React at a constant temperature of 240℃ for 20 min under N2 environment. Then, inject the zinc precursor solution No. 1 from step a) into the three-necked flask with a syringe and react for 60 min. The volume ratio of the injected precursor solution to the mixed solution in the flask is 1:2.

[0066] e) Inject the same amount of zinc precursor solution No. 2 from step b) into the reaction flask in step d), and react at a constant temperature of 240°C for 60 min;

[0067] f) Inject the same amount of zinc precursor solution No. 3 from step c) into the reaction flask in step e), and react at a constant temperature of 240℃ for 60 min. After the reaction is completed, cool the mixture to room temperature in an ice bath to obtain the ZnCuGaInS / ZnS quantum dot stock solution.

[0068] g) Add ethyl acetate at a volume ratio of 1:2 to the ZnCuGaInS / ZnS quantum dot stock solution obtained in step f) and centrifuge at high speed to remove the solvent in the stock solution. Then disperse the precipitate obtained by centrifugation in toluene and centrifuge at high speed a second time to remove the larger nanocrystals. Keep the supernatant to obtain ZnCuGaInS / ZnS dispersion.

[0069] (2) Quantum dot surface ligand exchange: Pentaerythritol tetramercaptoacetate was dissolved in toluene to obtain a pentaerythritol tetramercaptoacetate solution; the ZnCuGaInS / ZnS quantum dots and pentaerythritol tetramercaptoacetate dispersion were mixed with the pentaerythritol tetramercaptoacetate solution at a mass ratio of 1:35, and the mixture was stirred at 1000 rpm for 4 h under nitrogen protection to obtain a white quantum dot dispersion after surface ligand exchange;

[0070] (3) Coating organic particles: PMMA particles with a particle size of 7 μm were dispersed in toluene solution. 3% (by mass) of dispersant BYK-156 (by mass of PMMA particles) was added to assist dispersion. Then, a white quantum dot dispersion with surface ligand exchange and photoinitiator TPO were added. The mass ratio of added white quantum dots to PMMA particles was 1:15, and the mass of the added photoinitiator was 2% of the total mass of PMMA particles and white quantum dots. At 190 W / m 2 After ultraviolet irradiation and stirring at 500 rpm for 2 hours, the mixture was dried to obtain white light quantum dot-coated organic particles.

[0071] (4) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, white light quantum dot coated organic particles, curing agent, antistatic agent and dispersant in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0072] (5) Coating: The coating solution was coated onto the surface of the white reflective base film using an OSP-20 wire rod. The coating amount of white quantum dots coated with organic particles was 1.8 g / m. 2 After curing at 100℃ for 3 minutes, the coated reflective film containing white light quantum dots coated with organic particles is obtained.

[0073] Example 2:

[0074] A coated reflective film containing white quantum dot-coated organic particles includes a 150 μm thick white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) and a coating layer applied to the surface of the white reflective base film; by weight, the raw materials in the coating layer include 6.5 parts white quantum dot-coated organic particles, 82 parts thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts curing agent, 0.7 parts antistatic agent, and 2.8 parts dispersant BYK-156.

[0075] The preparation method of the above-mentioned coating reflective film containing white light quantum dots coated with organic particles includes the following steps:

[0076] (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion: The method is the same as in Example 1;

[0077] (2) Quantum dot surface ligand exchange: Pentaerythritol tetramercaptoacetate was dissolved in toluene to obtain a pentaerythritol tetramercaptoacetate solution; the ZnCuGaInS / ZnS quantum dots and pentaerythritol tetramercaptoacetate dispersion and the pentaerythritol tetramercaptoacetate solution were mixed at a mass ratio of 1:36 and stirred at 800 rpm for 5 h under nitrogen protection to obtain a white light quantum dot dispersion after surface ligand exchange;

[0078] (3) Coating organic particles: PMMA particles with a particle size of 7 μm were dispersed in toluene solution. BYK-156 dispersant (2% by mass of PMMA particles) was added to assist dispersion. Then, a white quantum dot dispersion with surface ligand exchange and photoinitiator TPO were added. The mass ratio of added white quantum dots to PMMA particles was 1:18, and the mass of the added photoinitiator was 2% of the total mass of PMMA particles and white quantum dots. At 180 W / m 2 After ultraviolet irradiation and stirring at 600 rpm for 3 hours, the mixture was dried to obtain white light quantum dot-coated organic particles.

[0079] (4) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, white light quantum dot coated organic particles and additives in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0080] (5) Coating: The coating solution was coated onto the surface of the white reflective base film using an OSP-20 wire rod. The coating amount of white quantum dots coated with organic particles was 1.8 g / m. 2 After curing at 90℃ for 4 minutes, the coated reflective film containing white light quantum dots coated with organic particles is obtained.

[0081] Example 3:

[0082] A coated reflective film containing white light quantum dots coated with organic particles includes a white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) with a thickness of 150 μm and a coating layer coated on the surface of the white reflective base film; by weight, the raw materials in the coating layer include 6.8 parts of white light quantum dot coated organic particles, 82 parts of thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts of curing agent, 0.7 parts of antistatic agent and 2.5 parts of dispersant BYK-156.

[0083] The preparation method of the above-mentioned coating reflective film containing white light quantum dots coated with organic particles includes the following steps:

[0084] (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion: The method is the same as in Example 1;

[0085] (2) Quantum dot surface ligand exchange: Pentaerythritol tetramercaptoacetate was dissolved in toluene to obtain a pentaerythritol tetramercaptoacetate solution; the ZnCuGaInS / ZnS quantum dot dispersion and the pentaerythritol tetramercaptoacetate solution were mixed at a mass ratio of ZnCuGaInS / ZnS quantum dots to pentaerythritol tetramercaptoacetate of 1:40, and stirred at 1500 rpm for 4 h under nitrogen protection to obtain a white quantum dot dispersion after surface ligand exchange;

[0086] (3) Coating organic particles: PMMA particles with a particle size of 7 μm were dispersed in toluene solution. BYK-156 dispersant (3% by mass of PMMA particles) was added to assist dispersion. Then, a white quantum dot dispersion with surface ligand exchange and photoinitiator TPO were added. The mass ratio of added white quantum dots to PMMA particles was 1:20, and the mass of the added photoinitiator was 2% of the total mass of PMMA particles and white quantum dots. At 200 W / m 2 After ultraviolet irradiation and stirring at 400 rpm for 2 hours, the mixture was dried to obtain white light quantum dot-coated organic particles.

[0087] (4) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, white light quantum dot coated organic particles and additives in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0088] (5) Coating: The coating solution was coated onto the surface of the white reflective base film using an OSP-20 wire rod. The coating amount of white quantum dots coated with organic particles was 1.8 g / m. 2 After curing at 120℃ for 2 minutes, the coated reflective film containing white light quantum dots coated with organic particles is obtained.

[0089] Example 4:

[0090] A coated reflective film containing white quantum dot-coated organic particles includes a 150 μm thick white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) and a coating layer applied to the surface of the white reflective base film. By weight, the raw materials in the coating layer include 4 parts white quantum dot-coated organic particles, 85 parts thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts curing agent, 0.7 parts antistatic agent, and 2.3 parts dispersant BYK-156; the rest are the same as in Example 1.

[0091] Example 5:

[0092] A coated reflective film containing white quantum dot-coated organic particles includes a 150 μm thick white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) and a coating layer applied to the surface of the white reflective base film. By weight, the raw materials in the coating layer include 8 parts white quantum dot-coated organic particles, 82 parts thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts curing agent, 0.7 parts antistatic agent, and 1.3 parts dispersant BYK-156; the rest are the same as in Example 1.

[0093] Example 6:

[0094] The difference between Example 6 and Example 1 is that in the white light quantum dot-coated organic particles, the organic particles are PA particles with a particle size of 3 μm; the rest are the same as in Example 1.

[0095] Example 7:

[0096] The difference between Example 7 and Example 1 is that in the white light quantum dot-coated organic particles, the organic particles are PET particles with a particle size of 40 μm; the rest are the same as in Example 1.

[0097] Comparative Example 1:

[0098] Uncoated white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150).

[0099] Comparative Example 2 (replaced with CdSe quantum dots):

[0100] A quantum dot-coated organic particle coating includes a white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) with a thickness of 150 μm and a coating layer applied to the surface of the white reflective base film; by weight, the raw materials in the coating layer include 6.3 parts of quantum dot-coated organic particles, 82 parts of thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts of curing agent, 0.7 parts of antistatic agent, and 3 parts of dispersant BYK-156.

[0101] The preparation method of the above-mentioned reflective coating containing organic particles coated with sub-dots includes the following steps:

[0102] (1) Preparation of CdSe quantum dot dispersion: CdSe powder (purchased from Nano Crystal Technology) was dispersed in toluene solvent to obtain a CdSe quantum dot dispersion with a mass fraction of 1%;

[0103] (2) Quantum dot surface ligand exchange: Pentaerythritol tetramercaptoacetate was dissolved in toluene to obtain a pentaerythritol tetramercaptoacetate solution; CdSe quantum dot dispersion and pentaerythritol tetramercaptoacetate solution were mixed at a mass ratio of 1:35 and stirred at 1000 rpm for 4 h under nitrogen protection to obtain quantum dot dispersion after surface ligand exchange;

[0104] (3) Coating organic particles: PMMA particles with a particle size of 7 μm were dispersed in toluene solution. BYK-156 dispersant (3% by mass of PMMA particles) was added to assist dispersion. Then, a quantum dot dispersion with surface ligand exchange and photoinitiator TPO were added. The mass ratio of added CdSe quantum dots to PMMA particles was 1:15, and the mass of the added photoinitiator was 2% of the total mass of PMMA particles and CdSe quantum dots. At 190 W / m 2 After ultraviolet irradiation and stirring at 500 rpm for 2 hours, the mixture was dried to obtain quantum dot-coated organic particles.

[0105] (4) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, quantum dot coated organic particles and additives in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0106] (5) Coating: The coating solution was coated onto the surface of the white reflective base film using an OSP-20 wire rod. The coating amount of quantum dots coated with organic particles was 1.8 g / m². 2 After curing at 100℃ for 3 minutes, a coated reflective film containing organic particles with the specified content of sub-dots is obtained.

[0107] Comparative Example 3 (organic particles without white quantum dots):

[0108] A coated reflective film includes a white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) with a thickness of 150 μm and a coating layer coated on the surface of the white reflective base film; by weight, the raw materials in the coating layer include 6.3 parts of PMMA particles with a particle size of 7 μm, 82 parts of thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts of curing agent, 0.7 parts of antistatic agent, and 3 parts of dispersant BYK-156.

[0109] The above-mentioned method for preparing the coated reflective film includes the following steps:

[0110] (1) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, PMMA particles and additives in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0111] (2) Coating: The coating solution was applied to the surface of the white reflective base film using an OSP-20 wire rod. The coating amount of PMMA particles was 1.8 g / m². 2 The coated reflective film is obtained after curing at 100℃ for 3 minutes.

[0112] Comparative Example 4 (without organic particles):

[0113] A white quantum dot-coated reflective film includes a 150 μm thick white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) and a coating applied to the surface of the white reflective base film; by weight, the raw materials in the coating include 6.3 parts ZnCuGaInS / ZnS quantum dots, 82 parts thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts curing agent, 0.7 parts antistatic agent, and 3 parts dispersant BYK-156.

[0114] The preparation method of the above-mentioned coated reflective film containing white light quantum dots includes the following steps:

[0115] (1) Preparation of ZnCuGaInS / ZnS quantum dots: The ZnCuGaInS / ZnS dispersion prepared according to the method in Example 1 was centrifuged and the precipitate was dried to obtain ZnCuGaInS / ZnS quantum dots;

[0116] (2) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, ZnCuGaInS / ZnS quantum dots and additives in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0117] (5) Coating: The coating solution was coated onto the surface of the white reflective substrate using an OSP-20 wire rod. The coating amount of ZnCuGaInS / ZnS quantum dots was 1.8 g / m. 2 The coated reflective film containing white light quantum dots was obtained after curing at 100℃ for 3 minutes.

[0118] Comparative Example 5 (no surface ligand exchange of quantum dots):

[0119] The method for preparing the white light quantum dots coated organic particles in Comparative Example 5 is as follows:

[0120] (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion: The method is the same as in Example 1;

[0121] (2) Coating organic particles: PMMA particles with a particle size of 7 μm were dispersed in toluene solution. After adding 3% (w / w) of dispersant BYK-156 to assist dispersion, ZnCuGaInS / ZnS quantum dot dispersion and photoinitiator TPO were added. The mass ratio of added ZnCuGaInS / ZnS quantum dots to PMMA particles was 1:15, and the mass of the added photoinitiator was 2% of the total mass of PMMA particles and ZnCuGaInS / ZnS quantum dots. At 190 W / m 2 After ultraviolet irradiation and stirring at 500 rpm for 2 hours, the mixture was dried to obtain white light quantum dot-coated organic particles.

[0122] Everything else is the same as in Example 1.

[0123] Comparative Example 6 (Direct blending of white light quantum dots and organic particles):

[0124] A white light quantum dot coated reflective film includes a 150 μm thick white reflective base film (Ningbo Changyang Technology Co., Ltd., reflective film FDX150) and a coating applied to the surface of the white reflective base film; by weight, the raw materials in the coating include 0.4 parts ZnCuGaInS / ZnS quantum dots, 5.9 parts PMMA particles with a particle size of 7 μm, 82 parts thermosetting acrylic adhesive with a refractive index of 1.48, 8 parts curing agent, 0.7 parts antistatic agent, and 3 parts dispersant.

[0125] The preparation method of the above-mentioned coated reflective film containing white light quantum dots includes the following steps:

[0126] (1) Preparation of ZnCuGaInS / ZnS quantum dots: The ZnCuGaInS / ZnS dispersion prepared according to the method in Example 1 was centrifuged and the precipitate was dried to obtain ZnCuGaInS / ZnS quantum dots;

[0127] (2) Preparation of coating solution: First, mix ethyl acetate and butyl acetate in a volume ratio of 1:1 to prepare an organic mixed solvent. Then, dissolve thermosetting acrylic adhesive, ZnCuGaInS / ZnS quantum dots, PMMA particles and additives in the organic mixed solvent in proportion and mix evenly to prepare a coating solution. The mass-volume ratio of thermosetting acrylic adhesive to organic mixed solvent in the coating solution is 1:2.

[0128] (5) Coating: The coating solution was coated onto the surface of the white reflective substrate using an OSP-20 wire rod. The coating amount of ZnCuGaInS / ZnS quantum dots was 1.8 g / m. 2The coated reflective film containing white light quantum dots was obtained after curing at 100℃ for 3 minutes.

[0129] The performance of the coated reflective films prepared in the above embodiments and comparative examples was tested, and the results are shown in Table 1.

[0130] The testing methods for each performance aspect are as follows:

[0131] Brightness uniformity test: The coated reflective film is cut into 10.1-inch pieces and assembled into a 10.1-inch backlight module. A luminance meter (German model HS-1000) is used to perform 13-point sampling tests. The uniformity indicates the uniformity of the brightness test values ​​at each sampling point. The higher the uniformity, the better the uniformity.

[0132] Average luminance: Represents the average value of the luminance test results from the 13 sampled points.

[0133] Relative luminance: The relative luminance of each embodiment and the comparative example was calculated with the luminance of the white reflective base film provided in Comparative Example 1 as 100%. The relative luminance was calculated as (average luminance of the samples in each embodiment and the comparative example / average luminance of the sample in Comparative Example 1) × 100%.

[0134] Anti-adsorption test: Cut the coated reflective film into 10.1-inch pieces and assemble them into a 10.1-inch backlight module. After lighting up the backlight module, place it in a vacuum-capable adsorption testing device. After vacuuming, observe whether there are bright spots on the backlight module. More white spots indicate poor anti-adsorption, fewer white spots indicate average anti-adsorption, and no white spots indicate excellent anti-adsorption.

[0135] Table 1: Performance Test Results of Coated Reflective Film

[0136]

[0137] From the anti-adsorption performance test results in Table 1, large-particle-size PET particles (Example 7) exhibit superior anti-adsorption performance compared to small-particle-size PA (Example 6) and PMMA particles. The uncoated substrate (Comparative Example 1) shows the worst anti-adsorption performance. In Comparative Example 4, only quantum dots were added without adding organic particles, resulting in no improvement in anti-adsorption performance. However, as the particle size of the coated particles increases, the surface roughness of the coated reflective film increases, and the uniformity decreases, affecting the uniformity of light emission. From the brightness test results, the brightness improvement effect becomes more significant with the increase of the proportion of quantum dot-coated organic coated particles. This is because the increased proportion of quantum dots leads to an increase in the number of excited quantum dots in the coated reflective film, increasing the intensity of light reflected back to the upper part of the backlight module. In Comparative Example 3, without coating the organic particle surface with quantum dots, the brightness decreases. It is worth noting that because white quantum dots have optical gain across the entire visible light band, the brightness improvement effect is better than that of CdSe quantum dots with single green light band fluorescence emission in Comparative Example 2. In Comparative Example 5, no ligand exchange was performed on the surface of the white light quantum dots. Instead, organic particles were directly coated. Since the oleic acid and oleylamine ligands on the surface of the quantum dots could not form chemical cross-links with the surface of the organic coated particles, the effect on improving brightness was not much different from that of mechanical blending in Comparative Example 6. Furthermore, since the quantum dots could not be dispersed as uniformly as the organic coated particles, the uniformity of light output was also poor.

Claims

1. A coated reflective film containing white light quantum dots coated with organic particles, characterized in that, It includes a white reflective base film and a coating applied to the surface of the white reflective base film; the raw materials in the coating include white quantum dot-coated organic particles, adhesives, and additives; In the white quantum dot-coated organic particles, the white quantum dots are ZnCuGaInS / ZnS quantum dots obtained by surface ligand exchange through molecules containing thiol functional groups, and the organic particles are one or both of PMMA and PBMA particles, with a particle size of 3~50μm; in the white quantum dot-coated organic particles, the mass ratio of white quantum dots to organic particles is 1:14~25.

2. The coated reflective film containing white light quantum dots coated with organic particles according to claim 1, characterized in that, The molecule containing the thiol functional group is pentaerythritol tetramercaptoacetate and / or γ-mercaptopropyltrimethoxysilane; During surface ligand exchange, the mass ratio of ZnCuGaInS / ZnS quantum dots to molecules containing thiol functional groups is 1:30~50.

3. The coated reflective film containing white light quantum dots coated with organic particles according to claim 1, characterized in that, By weight, the raw materials in the coating include: 3-8 parts white light quantum dot-coated organic particles, 75-85 parts adhesive, and 8-12 parts additives; the refractive index of the adhesive is 1.43-1.

53.

4. The coated reflective film containing white light quantum dots coated with organic particles according to claim 3, characterized in that, The adhesive is one of thermosetting acrylic glue, polyurethane resin, epoxy resin, and polyvinyl alcohol acetal resin; the additive is at least one of dispersant, curing agent, and antistatic agent.

5. The coated reflective film containing white light quantum dots coated with organic particles according to claim 1 or 3, characterized in that, In the coating, the amount of white quantum dots coated with organic particles is 1.5~2.5 g / m². 2 .

6. The coated reflective film containing white light quantum dots coated with organic particles according to claim 1, characterized in that, The white reflective base film has a reflectivity >95%; the white reflective base film is one of the following: foamed polyethylene terephthalate base film, polypropylene base film, and polycarbonate base film.

7. A method for preparing a coating reflective film containing white light quantum dots coated with organic particles as described in any one of claims 1 to 6, characterized in that, step include: (1) Preparation of ZnCuGaInS / ZnS quantum dot dispersion; (2) Mix ZnCuGaInS / ZnS quantum dot dispersion with a molecular solution containing thiol functional groups, and stir the reaction to obtain white quantum dot dispersion after surface ligand exchange; (3) Add the white quantum dot dispersion after surface ligand exchange to the dispersion of organic particles, add a photoinitiator, stir and react under ultraviolet irradiation and dry to obtain white quantum dot-coated organic particles. (4) Add the raw materials for the coating to the organic solvent and mix them evenly to prepare the coating liquid; (5) Apply the coating liquid to the surface of the white reflective base film and cure it to obtain the final product.

8. The method for preparing a coated reflective film containing white light quantum dots coated with organic particles according to claim 7, characterized in that, The photoinitiator mentioned in step (3) is dimethylphenylphosphine or TPO; step (3) is performed at 180~200W / m 2 The reaction was carried out under ultraviolet irradiation and stirring at 400-600 rpm for 2-3 hours.

9. The method for preparing a coated reflective film containing white light quantum dots coated with organic particles according to claim 7, characterized in that, The organic solvent in the coating solution in step (4) is a mixed solvent of ethyl acetate and butyl acetate in a volume ratio of 1:0.5~2.

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