Light conversion film and method for manufacturing the same

Abstract

The present application relates to light conversion film preparation technical field, especially to a light conversion film and a preparation method thereof.The method comprises the following steps: adding light conversion material to a polymer source, mixing uniformly, and obtaining light conversion film polymer mixed material; uniformly coating the light conversion film polymer mixed material on the surface of polyethylene terephthalate film, covering a layer of polyethylene terephthalate film, and preparing light conversion film by using heat compression method; and curing the compressed light conversion film by irradiation under LED light source, and obtaining cured light conversion film.The advantage is that a new light conversion material, i.e., rhodamine B, is introduced into the polymer, and the prepared light conversion film can efficiently convert green light into red light required for plant photosynthesis, and has wide application prospect in the agricultural field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of light conversion film preparation, in particular to a light conversion film and a preparation method thereof. BACKGROUND

[0002] In the field of agricultural technology, luminescent materials with light conversion function are doped into polymer films to make light conversion agricultural films. Through the transition emission of the luminescent center, ultraviolet light (250-400 nm), green light (500-560 nm) and yellow light (580-595 nm) in sunlight can be selectively converted into red light necessary for photosynthesis of crops, effectively promoting the growth of crops (Polymers, 2022, 14, 851). Compared with LED light supplement technology, the advantages of light conversion agricultural film in energy saving and emission reduction are as follows: 1) the entire light conversion process does not produce energy consumption by using sunlight to excite light conversion materials; 2) the increase of red light can change the phototaxis of pests, greatly reducing the incidence of aphid and whitefly pests, and greatly reducing the use of pesticides and fertilizers; 3) in the down-conversion process of photoluminescence, the light conversion material will release heat due to the Stokes effect (J. Mater. Chem. C, 2021, 9, 8066), which can effectively increase the temperature in the facility greenhouse, thereby reducing the carbon emissions caused by heating in the facility greenhouse in winter. As can be seen, light conversion agricultural film technology is the best technical approach for light supplement in facility agriculture. However, the current research on light conversion agricultural film at home and abroad is mainly based on rare earth organic complexes as light conversion materials. Rare earth organic complexes have the disadvantages of poor spectral matching and poor photothermal stability.

[0003] Rhodamine B is a commonly used fluorescent dye with good fluorescence performance and chemical stability, and is widely used in biomedical, material science, optoelectronics and other fields. In recent years, research on Rhodamine B materials has mainly focused on biomedical, optoelectronic devices, photocatalytic materials, dye-sensitized solar cells, environmental monitoring and other fields, involving material synthesis, device preparation, performance optimization and other aspects of research content. SUMMARY

[0004] The present application provides a light conversion film and a preparation method thereof to solve the above problems.

[0005] The first object of the present application is to provide a light conversion film and a preparation method thereof, comprising the following steps:

[0006] S1. Add light conversion materials to a polymer source, mix thoroughly, and obtain light conversion film polymer mixture;

[0007] S2. uniformly coating the light conversion film polymer mixture material on the surface of the polyethylene terephthalate film, and then covering a layer of polyethylene terephthalate film, and preparing a laminated film by hot compression method;

[0008] S3. curing the compressed laminated film by irradiation under an LED light source to obtain a cured light conversion film.

[0009] Preferably, the light conversion material is rhodamine B, and the polymer source is an acrylic resin.

[0010] Preferably, step S1 specifically comprises: preparing a rhodamine B ethanol solution with a concentration of 1-10 mg / mL; and adding the rhodamine B ethanol solution to an acrylic resin to obtain a rhodamine B-acrylic resin mixture material.

[0011] Preferably, the mass ratio of the rhodamine B ethanol solution to the acrylic resin is 7:1.

[0012] Preferably, the hot compression method in step S2 specifically comprises: placing the coated material in a shrink press, and performing shrinkage treatment at a temperature of 70-90℃ and a pressure of 130-200 PSI to obtain a laminated film.

[0013] Preferably, the shrinkage treatment is performed at a temperature of 80℃ and a pressure of 150 PSI.

[0014] Preferably, the emission wavelength of the LED light source in step S3 is 400-420 nm.

[0015] Preferably, the emission wavelength of the LED light source is 405 nm, and the irradiation time is 30 minutes.

[0016] The second object of the present application is to provide a light conversion film prepared by a light conversion film and a preparation method thereof, wherein the light conversion film is a three-layer film structure composed of a light conversion film polymer mixture material intermediate layer and two polyethylene terephthalate film layers on both sides.

[0017] Compared with the prior art, the present application can achieve the following beneficial effects:

[0018] Rhodamine B organic dyes are prepared by a chemical method, which can achieve ultra-high fluorescence quantum efficiency (PLQY) and stability, and are applied in the agricultural field to realize the preparation of a light conversion film that converts green light into red light.

[0019] A new light conversion material is introduced into a polymer, i.e., a high-performance light conversion material rhodamine B is introduced to prepare a polymer mixed material, and a light conversion film for converting green light into red light with high efficiency is prepared by compression. The introduction of the light conversion material rhodamine B can convert green light in sunlight into red light required for plant photosynthesis, and with the increase of the amount of rhodamine B introduced, the light conversion intensity will change. The rhodamine B material has high light emission performance and stability, and can realize long-time high-efficiency light conversion. The material and the polymer are used to prepare a light conversion film applied in the agricultural field for the first time and have a very promising application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is an absorption spectrum of a light conversion film according to an embodiment of the present application.

[0021] Figure 2 is a photoluminescence spectrum according to an embodiment of the present application; wherein curves 1, 2, 3 and 4 correspond to embodiments 1, 2, 3 and 4, respectively. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0023] In order to make the objectives, technical solutions and advantages of the present application clearer, further detailed descriptions will be made to the present application in combination with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not constitute a limitation on the present application.

[0024] Embodiment 1

[0025] The light conversion film preparation method of the present embodiment includes the following steps:

[0026] S1. 3 mg of rhodamine B material is dissolved in 3 ml of ethanol solution to prepare a rhodamine B ethanol solution with a concentration of 1 mg / ml; the rhodamine B ethanol solution is gradually added to the acrylic resin in a mass ratio of 7:1, and stirred in the air for 30 minutes to ensure that the rhodamine B is uniformly dispersed in the resin, thereby preparing a rhodamine B-acrylic resin mixed material;

[0027] S2. The Rhodamine B-acrylic resin mixed material is uniformly coated on the surface of the polyethylene terephthalate (PET) film using a doctor blade coating method to ensure uniform and consistent coating thickness. After coating, a layer of polyethylene terephthalate film is overlaid, and the laminate film is obtained by performing a calendering process at 80°C and a pressure of 150 pounds per square inch (PSI) in a calendering machine, so that the intermediate layer of the Rhodamine B-acrylic resin mixed material is tightly combined with the PET film, improving the adhesion and stability of the coating layer;

[0028] S3. The laminate film obtained after the calendering process in step S2 is exposed to a LED light source with an emission wavelength of 405 nm for irradiation for 30 minutes to cure the intermediate layer of the Rhodamine B-acrylic resin mixed material, ensuring complete curing and stability of the coating layer.

[0029] Figure 1 is the absorption spectrum of the light conversion film prepared in this example. It can be seen from Figure 1 that the absorption peak is at 552 nm. And the absorption peak does not change with the concentration, in the central region of green light, indicating that the light conversion film doped with Rhodamine B absorbs a wide range of green light.

[0030] Example 2

[0031] The light conversion film preparation method of this example includes the following steps:

[0032] S1. 12 mg of Rhodamine B material is dissolved in 3 ml of ethanol solution to prepare a Rhodamine B ethanol solution with a concentration of 4 mg / ml. The Rhodamine B ethanol solution is gradually added to the acrylic resin in a mass ratio of 7:1, and stirred in the air for 30 minutes to ensure that the Rhodamine B is uniformly dispersed in the resin, and a Rhodamine B-acrylic resin mixed material is prepared;

[0033] S2. The Rhodamine B-acrylic resin mixed material is uniformly coated on the surface of the polyethylene terephthalate (PET) film using a doctor blade coating method to ensure uniform and consistent coating thickness. After coating, a layer of polyethylene terephthalate film is overlaid, and the laminate film is obtained by performing a calendering process at 80°C and a pressure of 150 pounds per square inch (PSI) in a calendering machine, so that the intermediate layer of the Rhodamine B-acrylic resin mixed material is tightly combined with the PET film, improving the adhesion and stability of the coating layer;

[0034] S3. The laminate film obtained after the calendering process in step S2 is exposed to a LED light source with an emission wavelength of 405 nm for irradiation for 30 minutes to cure the intermediate layer of the Rhodamine B-acrylic resin mixed material, ensuring complete curing and stability of the coating layer.

[0035] Example 3

[0036] The light conversion film preparation method of the embodiment includes the following steps:

[0037] S1. Dissolve 24 mg of rhodamine B material in 3 ml of ethanol solution to prepare a rhodamine B ethanol solution with a concentration of 4 mg / ml; gradually add the rhodamine B ethanol solution to the acrylic resin at a mass ratio of 7:1, and stir in the air for 30 minutes to ensure that the rhodamine B is uniformly dispersed in the resin, thereby preparing a rhodamine B-acrylic resin mixed material;

[0038] S2. Use a doctor blade coating method to uniformly coat the rhodamine B-acrylic resin mixed material on the surface of a polyethylene terephthalate (PET) film, ensuring that the coating thickness is uniform and consistent; after coating, cover a layer of polyethylene terephthalate film, and place it in a shrink press for shrinkage treatment at 80°C and a pressure of 150 pounds per square inch (PSI), thereby obtaining a laminated film, allowing the rhodamine B-acrylic resin mixed material middle layer to be tightly combined with the PET film, and improving the adhesion and stability of the coating;

[0039] S3. Expose the laminated film obtained after shrinkage treatment in step S2 to a LED light source with an emission wavelength of 405 nm for irradiation for 30 minutes to cure the rhodamine B-acrylic resin mixed material middle layer, ensuring that the coating is completely cured and stable.

[0040] Embodiment 4

[0041] The light conversion film preparation method of the embodiment includes the following steps:

[0042] S1. Dissolve 24 mg of rhodamine B material in 3 ml of ethanol solution to prepare a rhodamine B ethanol solution with a concentration of 4 mg / ml; gradually add the rhodamine B ethanol solution to the acrylic resin at a mass ratio of 7:1, and stir in the air for 30 minutes to ensure that the rhodamine B is uniformly dispersed in the resin, thereby preparing a rhodamine B-acrylic resin mixed material;

[0043] S2. Use a doctor blade coating method to uniformly coat the rhodamine B-acrylic resin mixed material on the surface of a polyethylene terephthalate (PET) film, ensuring that the coating thickness is uniform and consistent; after coating, cover a layer of polyethylene terephthalate film, and place it in a shrink press for shrinkage treatment at 80°C and a pressure of 150 pounds per square inch (PSI), thereby obtaining a laminated film, allowing the rhodamine B-acrylic resin mixed material middle layer to be tightly combined with the PET film, and improving the adhesion and stability of the coating;

[0044] S3. Expose the laminated film obtained after shrinkage treatment in step S2 to a LED light source with an emission wavelength of 405 nm for irradiation for 30 minutes to cure the rhodamine B-acrylic resin mixed material middle layer, ensuring that the coating is completely cured and stable.

[0045] Comparative Example 1

[0046] The method for preparing the film without light conversion capability of the present comparative example comprises the following steps:

[0047] S1. uniformly coat the surface of a polyethylene terephthalate (PET) film with an acrylic resin material using a doctor blade coating method, ensuring that the coating thickness is uniform; the acrylic resin layer is between two layers of polyethylene terephthalate barrier film, and the PET film coated with the acrylic resin is placed in a shrink press for shrinkage treatment at 80°C and a pressure of 150 pounds per square inch (PSI), to obtain a light conversion film, so that the acrylic resin coating is tightly combined with the PET film, improving the adhesion and stability of the coating;

[0048] S2. expose the laminated film obtained after shrinkage treatment in step S1 to an LED light source with an emission wavelength of 405 nm for 30 minutes to cure the nanocomposite intermediate layer, ensuring that the coating is completely cured and stable.

[0049] The properties of the light conversion films prepared in Examples 1-4 and Comparative Example 1 were compared, and the results are shown in Table 1 and Figure 2 :

[0050] Table 1 Detailed information of light conversion film

[0051]

[0052] As can be seen from Table 1, Comparative Example 1 has no photoluminescence, while the light conversion films of Examples 1-4 of the present application all have photoluminescence properties, and the emission wavelength gradually increases after the concentration of rhodamine B is increased.

[0053] Figure 2 The middle curves 1, 2, 3, and 4 correspond to the photoluminescence spectra of the light conversion films prepared in Examples 1, 2, 3, and 4, respectively. As can be seen from the figure, the light conversion films prepared in Examples 1-4 have a red shift of the emission peak with increasing concentration of rhodamine B, and are all in the red light region, indicating that the material emits red light.

[0054] It should be understood that the various forms of the flow shown above can be reordered, added, or deleted steps. For example, the steps described in the present disclosure can be performed in parallel, in sequence, or in a different order, as long as the desired results of the technical solutions of the present disclosure can be achieved, which is not limited herein.

[0055] The above detailed description does not limit the scope of the application. Various modifications, combinations, sub-combinations and alternatives can be made to the detailed description. Any modification, equivalent replacement and improvement etc. made within the spirit and principle of the application shall be included in the scope of the application.

Claims

1. A light-converting thin film, characterized in that, The light-converting film is a three-layer film structure composed of a middle layer of light-converting film polymer mixture material and two polyethylene terephthalate film layers on both sides. The preparation method includes the following steps: S1. Add the light-converting material to the polymer source and mix thoroughly to obtain a light-converting thin film polymer mixture; the light-converting material is Rhodamine B, and the polymer source is acrylic resin; Specifically, the process includes: preparing an ethanol solution of Rhodamine B with a concentration of 1-10 mg / mL; gradually adding the ethanol solution of Rhodamine B to an acrylic resin to obtain a Rhodamine B-acrylic resin mixture; the mass ratio of the ethanol solution of Rhodamine B to the acrylic resin is 7:

1. S2. The light-converting thin film polymer mixture is uniformly coated on the surface of the polyethylene terephthalate film, and then covered with another layer of polyethylene terephthalate film. A laminated film is prepared by hot compression. The hot compression method specifically includes: placing the coated material in a compression press and performing compression treatment at a temperature of 70~90℃ and a pressure of 130~200psi to obtain a laminated film. S3. The compressed laminate is cured by irradiation under an LED light source to obtain a cured light-converting film.

2. The light-converting thin film according to claim 1, characterized in that: The compression treatment is performed at a temperature of 80°C and a pressure of 150 psi.

3. The light-converting thin film according to claim 2, characterized in that: In step S3, the emission wavelength of the LED light source is 400~420nm.

4. The light-converting thin film according to claim 3, characterized in that: The LED light source emits light at a wavelength of 405nm and is irradiated for 30 minutes.

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