A high-stability quantum dot diffusion plate and its preparation method

Abstract

The present invention belongs to the field of optical display, and specifically relates to a high-stability quantum dot diffusion plate and a preparation method thereof. In order to solve the problem of poor optical performance stability of existing quantum dot diffusion plates, the present invention provides a quantum dot diffusion plate and a preparation method thereof. The quantum dot diffusion plate comprises a first upper barrier layer, a second upper barrier layer, a quantum dot layer, a second lower barrier layer and a first lower barrier layer in sequence. The quantum dot diffusion plate is formed in one step by five-layer co-extrusion. The quantum dot layer is formed by a modified polystyrene resin system, the first barrier layer is composed of a modified polyethylene resin system, and the second barrier layer is composed of a modified polyvinyl alcohol resin system. The quantum dot diffusion plate provided by the present invention utilizes reactive blending to improve the compatibility of different polymers, combines the oxygen barrier properties of polyvinyl alcohol with the water barrier properties of polyethylene, greatly improves the water and oxygen resistance of the overall structure, and makes the quantum dot diffusion plate have excellent optical stability.

Description

Technical Field

[0001] The present invention belongs to the field of optical display, and in particular relates to a high-stability quantum dot diffusion plate and a preparation method thereof. Background Art

[0002] Quantum dots (QDs) are nanoparticles with a size smaller than or close to the exciton Bohr radius of bulk materials that exhibit quantum effects. Their unique structure results in quantum size effects, macroscopic quantum tunneling, dielectric confinement, and surface effects, resulting in unique physical and chemical properties and exceptional luminescence performance. Quantum dot luminescence exhibits excellent optoelectronic properties, including high quantum yield, long fluorescence lifetime, excellent photostability, a broad absorption spectrum, a narrow half-width (FWHM) of the fluorescence spectrum, good symmetry, and easily controllable fluorescence peak position. As a result, quantum dots are beginning to replace traditional phosphors in a wide range of applications, including materials science and display devices. However, quantum dots currently suffer from poor water and oxygen resistance during use. This means that when exposed to air, quantum dots are easily oxidized by oxygen and water vapor in the air, resulting in a decrease in fluorescence intensity. To address this issue, quantum dot film products typically utilize magnetron sputtering or vapor deposition to deposit a dense inorganic layer (such as silicon nitride, silicon oxide, or aluminum oxide) onto the substrate surface. This layer acts as a barrier to water and oxygen permeation, maintaining the optical stability of the quantum dot film during use. However, the above solution results in a substantial increase in cost, limiting the large-scale use of quantum dot films.

[0003] Quantum dot diffuser plates, another form of quantum dot backlight module, generally do not use the water and oxygen barrier film mentioned above. Instead, some adjustments are made to the quantum dot structure, such as thickening the quantum dot shell and inorganic coating, so that the quantum dot diffuser plate can also meet the requirements of use. Because it does not use expensive barrier films, its cost is much lower than that of quantum dot films, and therefore it has recently been widely used in the backlight display field. However, these treatment methods generally provide less protection for quantum dots than barrier films, making the optical performance stability of current quantum dot diffuser plates significantly weaker than that of quantum dot films in long-term use.

[0004] Polyethylene is an excellent non-polar material with very high water resistance, but it has a high permeability to gases like oxygen and carbon dioxide. Polyvinyl alcohol has very low permeability to gases like oxygen and carbon dioxide, as well as low water resistance. Combining these two materials as a barrier layer in a quantum dot diffuser plate through structural design can achieve both high water resistance and high oxygen resistance, thereby improving the optical stability of the quantum dot diffuser plate. However, because polyethylene's molecular structure is non-polar, while polyvinyl alcohol's is polar, the two are very incompatible, preventing direct inter-layer bonding. Summary of the Invention

[0005] To address the poor optical stability of existing quantum dot diffuser plates, the present invention provides a quantum dot diffuser plate and a method for its preparation. This quantum dot diffuser plate offers low cost and addresses the poor optical stability issues of existing quantum dot diffuser plates. The quantum dot diffuser plate provided by the present invention utilizes readily available, inexpensive raw materials, a simple process, and low cost, enabling rapid industrial production and large-scale application.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] The present invention provides a quantum dot diffusion plate, which includes a first upper barrier layer, a second upper barrier layer, a quantum dot layer, a second lower barrier layer and a first lower barrier layer.

[0008] The present invention provides a quantum dot diffusion plate, which sequentially comprises a first upper barrier layer, a second upper barrier layer, a quantum dot layer, a second lower barrier layer and a first lower barrier layer.

[0009] In the quantum dot diffusion plate, no bonding layer is provided between the layers.

[0010] The quantum dot diffusion plate is composed of a first upper barrier layer, a second upper barrier layer, a quantum dot layer, a second lower barrier layer and a first lower barrier layer in sequence.

[0011] The quantum dot diffusion plate is formed by five-layer co-extrusion.

[0012] The quantum dot diffusion plate has a sandwich symmetrical structure.

[0013] The first upper barrier layer and the first lower barrier layer are the same and are both referred to as first barrier layers.

[0014] The second upper barrier layer and the second lower barrier layer are the same and are both referred to as the second barrier layer for short.

[0015] Furthermore, the first barrier layer is made of polyethylene resin, and the second barrier layer is made of polyvinyl alcohol resin. The quantum dot diffuser plate provided by the present invention combines the oxygen barrier properties of polyvinyl alcohol with the water barrier properties of polyethylene, significantly enhancing the overall structure's resistance to water and oxygen, and resulting in excellent optical stability.

[0016] Furthermore, the quantum dot layer of the quantum dot diffuser plate is formed from a modified polystyrene resin system comprising polystyrene, metallocene polyethylene, peroxide, styrene monomer, and quantum dot powder. The raw materials for the quantum dot layer are blended and then reactively extruded to form the quantum dot layer. The blending process can be direct blending of solids and liquids.

[0017] Furthermore, the quantum dot powder includes red quantum dot powder, or green quantum dot powder, or a combination of red quantum dot powder and green quantum dot powder.

[0018] Furthermore, the modified polystyrene resin system (i.e., quantum dot layer) is formulated as follows: 70-90 parts of polystyrene, 10-30 parts of metallocene polyethylene, 1-3 parts of peroxide, 2-5 parts of styrene monomer, and 2-4 parts of quantum dot powder; the quantum dot powder includes 0-2 parts of red quantum dot powder and 0-2 parts of green quantum dot powder; the total number of polystyrene and metallocene polyethylene is 100 parts; the numbers are in parts by weight. The aforementioned technical solution includes embodiments 1-7. During the extrusion process, the peroxide decomposes to produce free radicals, which trigger the styrene monomer to react with the polystyrene and metallocene polyethylene to form a block polymer, thereby improving the compatibility of polystyrene with metallocene polyethylene and improving the adhesion to the second barrier layer. The quantum dot (QD) layer has metallocene polyethylene added, and vinyl alcohol-ethylene copolymer is added to the second barrier layer to introduce polyethylene segments, which improve the adhesion between the quantum dot layer and the second barrier layer through this polyethylene segment.

[0019] Furthermore, the peroxide is one of diisopropylbenzene oxide, di(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane or 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane.

[0020] Furthermore, the thickness of the quantum dot layer is 0.5-1.5 mm.

[0021] Furthermore, the first barrier layer of the quantum dot diffusion plate is composed of a modified polyethylene resin system, wherein the modified polyethylene resin system is obtained by blending metallocene polyethylene and ethylene-vinyl acetate copolymer and then extruding.

[0022] Furthermore, the modified polyethylene resin system (i.e., the first barrier layer) is formulated as follows: 80-95 parts of metallocene polyethylene and 5-20 parts of ethylene-vinyl acetate copolymer; the total number of parts of the metallocene polyethylene and ethylene-vinyl acetate copolymer is 100 parts; the parts are by weight. The addition of ethylene-vinyl acetate copolymer to the formula serves to improve the compatibility between the first and second barrier layers and enhance the adhesion between the layers, thereby eliminating the need for an adhesive. The ethylene-vinyl acetate copolymer in the first barrier layer and the vinyl alcohol-ethylene copolymer in the second barrier layer work together to enhance adhesion. The ethylene-vinyl acetate copolymer in the first barrier layer enhances the polarity of the system and increases compatibility with polyvinyl alcohol. At the same time, the vinyl alcohol-ethylene copolymer in the second barrier film layer enhances compatibility with polyethylene through the polyethylene segments of the copolymer, thereby enhancing adhesion between the second barrier layer and the first barrier layer.

[0023] Furthermore, the thickness of the first barrier layer is 0.1-0.2 mm.

[0024] Furthermore, the second barrier layer of the quantum dot diffusion plate is composed of a modified polyvinyl alcohol resin system.

[0025] The modified polyvinyl alcohol resin system of the second barrier layer is obtained by mixing polyvinyl alcohol, vinyl alcohol-ethylene copolymer and caprolactam and then extruding.

[0026] Furthermore, the modified polyvinyl alcohol resin system (i.e., the second barrier layer) is formulated as follows: 10-20 parts vinyl alcohol-ethylene copolymer, 80-90 parts polyvinyl alcohol, and 2-5 parts caprolactam; the total weight of the vinyl alcohol-ethylene copolymer and polyvinyl alcohol is 100 parts; the weights are expressed in parts by weight. In this formulation, the polyvinyl alcohol improves the oxygen barrier efficiency, the vinyl alcohol-ethylene copolymer enhances adhesion to the first barrier layer, and the caprolactam serves as a plasticizer.

[0027] Furthermore, the thickness of the second barrier layer is 0.1-0.2 mm.

[0028] Furthermore, the average degree of polymerization of the polyvinyl alcohol is 2400-2500.

[0029] Furthermore, the melt index of the metallocene polyethylene is 0.3 g / 10 min.

[0030] Furthermore, the melt index of the polystyrene is 8.0 g / 10 min.

[0031] Furthermore, the mass content of vinyl acetate in the ethylene-vinyl acetate copolymer is 28%.

[0032] Furthermore, the mass content of the ethylene block in the vinyl alcohol-ethylene copolymer is 24%.

[0033] The quantum dot diffuser plate provided by the present invention utilizes peroxide decomposition during the extrusion process of the quantum dot layer to generate free radicals, which trigger a reaction between styrene monomer, polystyrene, and metallocene polyethylene to form a block polymer. This improves the compatibility of polystyrene and metallocene polyethylene, thereby enhancing adhesion to the second barrier layer. The first and second barrier layers utilize the addition of vinyl alcohol-ethylene copolymer to enhance adhesion to adjacent layers. This allows the overall quantum dot diffuser plate to combine the oxygen barrier properties of polyvinyl alcohol with the water barrier properties of polyethylene, significantly enhancing the overall structure's resistance to water and oxygen, and resulting in excellent optical stability.

[0034] Furthermore, the modified polystyrene resin system (i.e., quantum dot layer) is formulated as follows: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts peroxide, 4 parts styrene monomer, and 4 parts quantum dot powder; the quantum dot powder includes 2 parts red quantum dot powder and 2 parts green quantum dot powder; the parts are expressed in parts by weight. The thickness of the quantum dot layer is 1-1.5 mm. The modified polyethylene resin system (i.e., first barrier layer) is formulated as follows: 80-95 parts metallocene polyethylene and 5-20 parts ethylene-vinyl acetate copolymer; the total of the metallocene polyethylene and ethylene-vinyl acetate copolymer is 100 parts; the parts are expressed in parts by weight. The thickness of the first barrier layer is 0.1-0.2 mm. The modified polyvinyl alcohol resin system (i.e., the second barrier layer) has a formula of: 10-20 parts vinyl alcohol-ethylene copolymer, 80-90 parts polyvinyl alcohol, and 2-5 parts caprolactam; the total weight of the vinyl alcohol-ethylene copolymer and polyvinyl alcohol is 100 parts; the weights are expressed in parts by weight. The thickness of the second barrier layer is 0.1-0.2 mm. The aforementioned technical solution includes Examples 1-5.

[0035] Furthermore, the modified polystyrene resin system (i.e., quantum dot layer) has a formula of: 80 parts of polystyrene, 20 parts of metallocene polyethylene, 2 parts of peroxide, 4 parts of styrene monomer, and 4 parts of quantum dot powder; the quantum dot powder includes 2 parts of red quantum dot powder and 2 parts of green quantum dot powder; the parts are in parts by weight. The thickness of the quantum dot layer is 1 mm. The modified polyethylene resin system (i.e., the first barrier layer) has a formula of: 90 parts of metallocene polyethylene and 10 parts of ethylene-vinyl acetate copolymer; the parts are in parts by weight. Furthermore, the thickness of the first barrier layer is 0.2 mm. The modified polyvinyl alcohol resin system (i.e., the second barrier layer) has a formula of: 15 parts of vinyl alcohol-ethylene copolymer, 85 parts of polyvinyl alcohol, and 4 parts of caprolactam; the parts are in parts by weight. The thickness of the second barrier layer is 0.2 mm. The aforementioned technical solution includes Example 1.

[0036] The invention provides a method for preparing a quantum dot diffusion plate. The various layers of the diffusion plate are co-extruded.

[0037] Furthermore, in the preparation process of the quantum dot diffuser plate, the raw materials of each layer of the diffuser plate are mixed in a twin-screw extruder and then extruded into a multi-layer co-extrusion die to obtain the quantum dot diffuser plate.

[0038] The beneficial effects of the present invention are as follows:

[0039] The design of this invention is an upgrade of the existing mass production process for quantum dot diffuser plates, enabling rapid, large-scale production while retaining the existing process. The polymer system and design structure employed in this invention exhibit strong resistance to water and oxygen, maintaining excellent optical stability even under harsh aging conditions (high temperature, high humidity, and strong blue light). The polymer formulation employed in this invention facilitates reactive extrusion, improving interlayer compatibility and eliminating the need for additional adhesives between layers, resulting in a simple process and low cost.

[0040] The quantum dot diffuser plate produced by the present invention is a type of optical plate with high brightness and high stability, and has broad and excellent application prospects in the field of display devices. The quantum dot diffuser plate provided by the present invention has excellent optical stability and strong compatibility with the appearance design of display devices. The design requires inexpensive and readily available raw materials, and the process is simple and low-cost, which can be used for efficient industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic structural diagram of the high-stability quantum dot diffusion plate provided by the present invention.

[0042] Reference numerals in the figures:

[0043] 10 first upper barrier layer (referred to as the first barrier layer),

[0044] 20 second upper barrier layer (referred to as the second barrier layer),

[0045] 30 quantum dot layers,

[0046] 40 second lower barrier layer (referred to as the second barrier layer),

[0047] 50 first lower barrier layer (referred to as the first barrier layer), DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be further described below in conjunction with this embodiment and the accompanying drawings.

[0049] like Figure 1 As shown, the present invention provides a quantum dot diffusion plate, which has a sandwich symmetrical structure and a total of five layers. The first to fifth layers are respectively a first upper barrier layer 10, a second upper barrier layer 20, a quantum dot layer 30, a second lower barrier layer 40, and a first lower barrier layer 50.

[0050] Example 1

[0051] like Figure 1As shown, the present invention provides a quantum dot diffusion plate. The quantum dot diffusion plate of the present invention has a sandwich symmetrical structure with a total of five layers. The first to fifth layers are respectively a first barrier layer 10, a second barrier layer 20, a quantum dot layer 30, a second barrier layer 40, and a first barrier layer 50.

[0052] The properties of the polymers used are as follows: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in the ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of the ethylene block in the vinyl alcohol-ethylene copolymer is 24%.

[0053] The modified polyethylene resin system of the first barrier layer has a weight ratio of 90 parts of metallocene polyethylene and 10 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0054] The modified polyvinyl alcohol resin system of the second barrier layer has a weight ratio of: 15 parts of vinyl alcohol-ethylene copolymer, 85 parts of polyvinyl alcohol, and 4 parts of caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0055] The modified polystyrene resin system for the quantum dot layer is formulated by weight as follows: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts dicumyl oxide, 4 parts styrene monomer, 2 parts red quantum dot powder, and 2 parts green quantum dot powder. A twin-screw extruder is used, with each section set at 160°C. This layer is a solid-liquid blend, with a chemical reaction occurring during the extrusion process.

[0056] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain a final quantum dot diffusion plate. The thickness of each layer is 1mm for the quantum dot layer, 0.2mm for the first barrier layer, and 0.2mm for the second barrier layer, with a total thickness of 1.8mm.

[0057] Example 2

[0058] As described in Example 1, the properties of the polymer used in the quantum dot diffusion plate are as follows: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of ethylene block in vinyl alcohol-ethylene copolymer is 24%.

[0059] The modified polyethylene resin system used for the first barrier layer has a weight ratio of 80 parts of metallocene polyethylene and 20 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0060] The modified polyvinyl alcohol resin system used for the second barrier layer has a weight ratio of 15 parts vinyl alcohol-ethylene copolymer, 85 parts polyvinyl alcohol, and 4 parts caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0061] The modified polystyrene resin system used for the quantum dot layer has a weight ratio of: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 4 parts styrene monomer, 2 parts red quantum dot powder, and 2 parts green quantum dot powder. A twin-screw extruder was used, with each section set at 160°C.

[0062] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain the final quantum dot diffusion plate. The thickness of each layer is 1mm for the quantum dot layer, 0.1mm for the first barrier layer, 0.2mm for the second barrier layer, and the total thickness is 1.6mm.

[0063] Example 3

[0064] As described in Example 1, the quantum dot diffusion plate uses the following polymer properties: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of ethylene block in vinyl alcohol-ethylene copolymer is 24%.

[0065] The modified polyethylene resin system used for the first barrier layer has a weight ratio of 95 parts of metallocene polyethylene and 5 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0066] The modified polyvinyl alcohol resin system used for the second barrier layer has a weight ratio of 15 parts vinyl alcohol-ethylene copolymer, 85 parts polyvinyl alcohol, and 4 parts caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0067] The modified polystyrene resin system used for the quantum dot layer has a weight ratio of: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts dicumyl oxide, 4 parts styrene monomer, 2 parts red quantum dot powder, and 2 parts green quantum dot powder. A twin-screw extruder was used, with each section set at 160°C.

[0068] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain a final quantum dot diffusion plate. The thickness of each layer is 1mm for the quantum dot layer, 0.2mm for the first barrier layer, and 0.2mm for the second barrier layer, with a total thickness of 1.8mm.

[0069] Example 4

[0070] As described in Example 1, the quantum dot diffusion plate uses the following polymer properties: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of ethylene block in vinyl alcohol-ethylene copolymer is 24%.

[0071] The modified polyethylene resin system used for the first barrier layer has a weight ratio of 90 parts of metallocene polyethylene and 10 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0072] The modified polyvinyl alcohol resin system used for the second barrier layer has a weight ratio of 10 parts vinyl alcohol-ethylene copolymer, 90 parts polyvinyl alcohol, and 5 parts caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0073] The modified polystyrene resin system used for the quantum dot layer has a weight ratio of: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts di(tert-butylperoxyisopropyl)benzene, 4 parts styrene monomer, 2 parts red quantum dot powder, and 2 parts green quantum dot powder. A twin-screw extruder was used, with each section set at 160°C.

[0074] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain a final quantum dot diffusion plate. The thickness of each layer is 1mm for the quantum dot layer, 0.2mm for the first barrier layer, 0.1mm for the second barrier layer, and a total thickness of 1.6mm.

[0075] Example 5

[0076] As described in Example 1, the quantum dot diffusion plate uses the following polymer properties: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of ethylene block in vinyl alcohol-ethylene copolymer is 24%.

[0077] The modified polyethylene resin system used for the first barrier layer has a weight ratio of 90 parts of metallocene polyethylene and 10 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0078] The modified polyvinyl alcohol resin system used for the second barrier layer has a weight ratio of 20 parts vinyl alcohol-ethylene copolymer, 80 parts polyvinyl alcohol, and 5 parts caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0079] The modified polystyrene resin system used for the quantum dot layer has a weight ratio of: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 4 parts styrene monomer, 2 parts red quantum dot powder, and 2 parts green quantum dot powder. A twin-screw extruder was used, with each section set at 160°C.

[0080] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain a final quantum dot diffusion plate. The thickness of each layer is 1.5mm for the quantum dot layer, 0.2mm for the first barrier layer, 0.1mm for the second barrier layer, and a total thickness of 2.1mm.

[0081] Example 6

[0082] As described in Example 1, the quantum dot diffusion plate uses the following polymer properties: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of ethylene block in vinyl alcohol-ethylene copolymer is 24%.

[0083] The modified polyethylene resin system used for the first barrier layer has a weight ratio of 90 parts of metallocene polyethylene and 10 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0084] The modified polyvinyl alcohol resin system used for the second barrier layer has a weight ratio of 15 parts vinyl alcohol-ethylene copolymer, 85 parts polyvinyl alcohol, and 4 parts caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0085] The modified polystyrene resin system used for the quantum dot layer has a weight ratio of: 70 parts polystyrene, 30 parts metallocene polyethylene, 3 parts dicumyl oxide, 5 parts styrene monomer, 0.1 parts red quantum dot powder, and 2 parts green quantum dot powder. A twin-screw extruder was used, with each section set at 160°C.

[0086] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain a final quantum dot diffusion plate. The thickness of each layer is 0.5mm for the quantum dot layer, 0.2mm for the first barrier layer, and 0.2mm for the second barrier layer, with a total thickness of 1.3mm.

[0087] Example 7

[0088] As described in Example 1, the quantum dot diffusion plate uses the following polymer properties: the melt index of polystyrene is 8.0 g / 10 min; the melt index of metallocene polyethylene is 0.3 g / 10 min; the mass content of vinyl acetate in ethylene-vinyl acetate copolymer is 28%; the average degree of polymerization of polyvinyl alcohol is 2400-2500; and the mass content of ethylene block in vinyl alcohol-ethylene copolymer is 24%.

[0089] The modified polyethylene resin system used for the first barrier layer has a weight ratio of 90 parts of metallocene polyethylene and 10 parts of ethylene-vinyl acetate copolymer. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0090] The modified polyvinyl alcohol resin system used for the second barrier layer has a weight ratio of 15 parts vinyl alcohol-ethylene copolymer, 85 parts polyvinyl alcohol, and 4 parts caprolactam. A twin-screw extruder is used, and the temperature of each section of the extruder is set at 160°C.

[0091] The modified polystyrene resin system used for the quantum dot layer has a weight ratio of: 90 parts polystyrene, 10 parts metallocene polyethylene, 1 part dicumyl oxide, 2 parts styrene monomer, 2 parts red quantum dot powder, and 0.1 part green quantum dot powder. A twin-screw extruder was used, with each section set at 160°C.

[0092] The above raw materials are mixed in a twin-screw extruder and then enter a multi-layer co-extrusion die to obtain a final quantum dot diffusion plate. The thickness of each layer is 0.5mm for the quantum dot layer, 0.2mm for the first barrier layer, and 0.2mm for the second barrier layer, with a total thickness of 1.3mm.

[0093] Comparative Example

[0094] The comparative example is a quantum dot diffusion plate produced by Nantong Chuangyida New Materials Co., Ltd., product model CPQ18B, and sample thickness 1.8 mm.

[0095] The test method of the quantum dot diffuser plate is as follows.

[0096] After cutting the above quantum dot diffusion plate into A4 size, it was tested for brightness and white point (i.e., color coordinate test, the data is Wx and Wy values) using a blue backlight module on a CS-2000 luminance meter. Afterwards, the samples were divided into 3 groups, and 5 samples in each group were placed in a high-temperature oven, a high-temperature and high-humidity oven, and a blue light box. After 1000 hours, the brightness and white point tests were carried out again and compared. Among them, the brightness and color coordinates of the data of each diaphragm were averaged. Furthermore, the temperature of the high-temperature oven was set to 80 degrees Celsius; the high-temperature and high-humidity box was set to 65 degrees Celsius and the humidity was 95%; the blue light box was set to 350mW / cm 2Strong blue light exposure. The test results are compared as follows:

[0097] Table 1 High temperature aging optical performance test results of the quantum dot diffusion plate provided in the embodiment and comparative example

[0098]

[0099]

[0100] Table 2 Test results of optical properties of quantum dot diffusion plates provided in Examples and Comparative Examples under high temperature and high humidity aging

[0101]

[0102] Table 3 Test results of strong blue light aging optical performance of quantum dot diffusion plates provided in Examples and Comparative Examples

[0103]

[0104] It can be concluded from the test results in Tables 1 to 3 that the quantum dot diffusion plates provided in Examples 1-7 have excellent stability and optical properties after being tested under high temperature, high temperature and humidity, and strong blue light irradiation. After the above-mentioned extreme test conditions, whether it is high temperature, high temperature and humidity or strong blue light irradiation, the brightness fluctuation range of the samples in the above embodiments is less than 10%, and the fluctuation range of the color coordinates is less than 0.01, which is better than the current mass-produced samples on the market (CPQ18B), especially the high temperature aging performance and strong blue light aging performance. The above test results show that the quantum dot diffusion plate has excellent stability and optical properties. In particular, the quantum dot diffusion plate provided in Example 1 has better comprehensive performance, and has good stability in high temperature, high temperature and humidity, and strong blue light irradiation tests, with a brightness fluctuation range of less than 5% and a color coordinate fluctuation range of less than 0.005.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A quantum dot diffuser plate, characterized in that: The quantum dot diffusion plate includes a first upper barrier layer, a second upper barrier layer, a quantum dot layer, a second lower barrier layer and a first lower barrier layer; the formula of the quantum dot layer is: 70-90 parts of polystyrene, 10-30 parts of metallocene polyethylene, 1-3 parts of peroxide, 2-5 parts of styrene monomer, and 2-4 parts of quantum dot powder; the quantum dot powder includes 0-2 parts of red quantum dot powder and 0-2 parts of green quantum dot powder; the total number of parts of polystyrene and metallocene polyethylene is 100 parts; the parts are by weight.

2. The quantum dot diffuser plate according to claim 1, characterized in that The peroxide is one of diisopropylbenzene oxide, di-tert-butyl peroxide isopropylbenzene, 2,5-dimethyl-2,5-di-tert-butyl peroxyhexane or 1,1-di-tert-butyl peroxy-3,3,5-trimethylcyclohexane.

3. The quantum dot diffuser plate according to claim 1, characterized in that The first upper barrier layer is the same as the first lower barrier layer, and the formula is: 80-95 parts of metallocene polyethylene and 5-20 parts of ethylene-vinyl acetate copolymer; the total parts of the metallocene polyethylene and ethylene-vinyl acetate copolymer is 100 parts; the parts are parts by weight.

4. The quantum dot diffuser plate according to claim 3, characterized in that The second upper barrier layer is the same as the second lower barrier layer, and has the following formula: 10-20 parts of vinyl alcohol-ethylene copolymer, 80-90 parts of polyvinyl alcohol, and 2-5 parts of caprolactam; the total number of parts of the vinyl alcohol-ethylene copolymer and polyvinyl alcohol is 100 parts; the parts are parts by weight.

5. The quantum dot diffuser plate according to claim 4, characterized in that: The thickness of the quantum dot layer is 0.5-1.5 mm; the first upper barrier layer and the first lower barrier layer are the same, with a thickness of 0.1-0.2 mm; the second upper barrier layer and the second lower barrier layer are the same, with a thickness of 0.1-0.2 mm.

6. The quantum dot diffuser plate according to claim 4, characterized in that The average degree of polymerization of the polyvinyl alcohol is 2400-2500, the melt index of the metallocene polyethylene is 0.3 g / 10 min, the melt index of the polystyrene is 8.0 g / 10 min, the mass content of vinyl acetate in the ethylene-vinyl acetate copolymer is 28%, and the mass content of the ethylene block in the vinyl alcohol-ethylene copolymer is 24%.

7. The quantum dot diffuser plate according to claim 6, characterized in that The quantum dot layer is formulated as follows: 80 parts polystyrene, 20 parts metallocene polyethylene, 2 parts peroxide, 4 parts styrene monomer, and 4 parts quantum dot powder; the quantum dot powder includes 2 parts red quantum dot powder and 2 parts green quantum dot powder; the thickness of the quantum dot layer is 1-1.5 mm; the first upper barrier layer is the same as the first lower barrier layer, and is formulated as follows: 80-95 parts metallocene polyethylene and 5-20 parts ethylene-vinyl acetate copolymer; the metallocene polyethylene and ethylene-vinyl acetate copolymer are The total number of parts of the vinyl ester copolymer is 100 parts; the first upper barrier layer is the same as the first lower barrier layer, and has a thickness of 0.1-0.2 mm; the second upper barrier layer is the same as the second lower barrier layer, and has a formula of: 10-20 parts of vinyl alcohol-ethylene copolymer, 80-90 parts of polyvinyl alcohol, and 2-5 parts of caprolactam; the total number of parts of the vinyl alcohol-ethylene copolymer and polyvinyl alcohol is 100 parts; the parts are by weight; the second upper barrier layer is the same as the second lower barrier layer, and has a thickness of 0.1-0.2 mm.

8. A method for preparing a quantum dot diffuser plate according to any one of claims 1 to 7, characterized in that: The quantum dot diffusion plate is formed by five-layer co-extrusion.

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