A photochromic dispersion material, a preparation method thereof, and a self-adapting light-adjusting smart window film made of the same

Abstract

The present application relates to a kind of photochromic dispersion materials, the photochromic dispersion material includes photochromic nanoparticles, polymer and solvent;Wherein, the photochromic nanoparticles are formed by photochromic nanoparticle precursor, and dispersed in the mixing process in solvent and after mixing;The photochromic nanoparticles are formed in non-orthogonal solvent or single solvent.The solvent is the solvent accepted in industry, so that photochromic dispersion material can be mass processed.The present application also relates to a kind of photochromic film, which has photochromic properties: under sunlight irradiation, the initially colorless transparent film will present blue tone, and there is strong absorption in near infrared band, but visible light band still maintains higher transmittance;In dark condition, the film will restore transparent state.The intelligent window film is greater than 15% between coloring state and transparent state Sunlight transmission change, while visible light transmittance change is greater than 15%.

Description

Technical Field

[0001] This invention relates to the field of photochromic materials, and in particular to a photochromic dispersion material, its preparation method, and an adaptive dimming smart window film made therefrom. Background Technology

[0002] Improving energy efficiency and reducing carbon emissions are crucial. Windows are considered the least energy-efficient part of a building facade due to radiative heat loss in winter and increased temperature from solar radiation in summer. To improve building energy efficiency and visible light comfort, smart windows are gaining increasing attention.

[0003] Smart window types include electrochromic (electric field switching), thermochromic (temperature-responsive), and photochromic (light intensity-responsive). Compared to electrochromic windows, thermochromic and photochromic smart windows are more popular due to their simple structure, passive light control, and zero energy consumption.

[0004] Many existing patents for photochromic window films, such as WO2008043853A2, CN217001448U, and CN106218172A, are based on organic molecules with photochromic properties. Literature studies of the organic molecules mentioned in these patents conclude that all these molecules only alter their transmission / absorption within a narrow wavelength range, primarily in the visible light spectrum. This results in modulation of visible light, rather than temperature control; and they all have some shortcomings.

[0005] Furthermore, photochromic materials covering most of the solar spectrum are typically inorganic, such as tungsten oxide (WO3). A major challenge with this material is fabricating it into transparent thin films. Tungsten oxide, described in the literature, exhibits excellent photochromic properties, usually based on thin films or nanoparticles that display scattering in both transparent and photochromic states. Synthesizing sufficiently small nanoparticles (less than 50 nm in diameter) to obtain low-scattering materials requires expensive and non-scalable methods, such as solvothermal synthesis combined with ball milling.

[0006] Furthermore, WO2024007275A1 describes a thin film with low scattering and significant sunlight modulation properties. However, this film has the following drawbacks: First, its processing requires two orthogonal solvents with significantly different polarities, which poses inconvenience for industrial production. Moreover, the described method uses hazardous chemicals such as dimethylformamide, a solvent unsuitable for large-scale industrial production. Second, during film formation, photochromic inorganic nanoparticles are formed and dispersed during the drying of the precursor solution. The choice of solvent results in the photochromic inorganic nanoparticles having a higher solubility in the precursor solvent than the polymer; therefore, the nanoparticles are formed and dispersed through supersaturated drying during film formation. Third, the claimed film is a standalone film consisting solely of a photochromic layer, prepared by coating a sol-gel material onto a glass substrate, drying the solvent, and demolding.

[0007] Therefore, it is very important to develop a photochromic dispersion material and an adaptive dimming smart window film that can be industrially prepared at low cost and on a large scale to overcome the above problems. Summary of the Invention

[0008] To address the aforementioned deficiencies, this invention discloses a photochromic dispersion material and an adaptive dimming smart window film made from the photochromic dispersion material. The photochromic dispersion material comprises photochromic nanoparticles, a polymer, and a solvent; the adaptive dimming smart window film consists of photochromic nanoparticles embedded within the polymer. The formation process of the adaptive dimming smart window film is based on an industrially standardized, fully wet chemical coating method using solvents and materials, suitable for large-scale industrial production. Under ultraviolet irradiation, the smart window film transitions from a transparent state to a colored state; in darkness, the smart window film reverts to a transparent state.

[0009] One object of the present invention is to provide a photochromic dispersion material, the photochromic dispersion material comprising photochromic nanoparticles, a polymer and a solvent;

[0010] in,

[0011] The photochromic nanoparticles are formed from photochromic nanoparticle precursors and dispersed during and after mixing in a solvent.

[0012] The photochromic nanoparticles are formed in solvents with similar polarities or in a single solvent.

[0013] Furthermore, the photochromic dispersion material also includes a dopant, which is a transition metal.

[0014] Furthermore, the transition metal is selected from one or more of ferric chloride, iodine, cuprous chloride, cupric chloride, or lithium chloride.

[0015] Furthermore, the molar ratio of the photochromic nanoparticles to the dopant is 100:(1-40).

[0016] Furthermore, the photochromic dispersion material also includes additives selected from one or more of wetting agents, stabilizers, or dyes; the additives can improve the wettability, stability, and / or color of the coating.

[0017] Furthermore, the photochromic nanoparticles are wide-bandgap semiconductor materials, which are selected from one or more of titanium dioxide, tungsten trioxide, or molybdenum trioxide.

[0018] Furthermore, the polymer is selected from one or more of polymethyl methacrylate or polyacrylic acid.

[0019] Furthermore, the solvent is selected from one or more of ethylene glycol, diethylene glycol, acetophenone, ethyl lactate, anisole, or cyclohexanone; the solvent is industrially acceptable and is not listed on the Candidate List of Substances of Very High Concern (SVHC).

[0020] Another object of the present invention is to provide a method for preparing the above-mentioned photochromic dispersion material, one embodiment of which includes the following steps:

[0021] S1. Add the polymer to the solvent, heat and stir to obtain solution 1;

[0022] S2. Add the photochromic nanoparticle precursor and dopant to the solvent and stir at room temperature or under heating conditions to obtain solution 2.

[0023] S3. Mix the solutions 1 and 2 together, then add the additives and stir until homogeneous to obtain a photochromic dispersion material.

[0024] Furthermore, in step S1, the heating temperature is 90-140°C.

[0025] Furthermore, in step S2, the heating temperature is 80-100℃.

[0026] Furthermore, the solvent in step S2 can be the same as or different from the solvent in step S1.

[0027] Another approach includes the following steps:

[0028] Photochromic nanoparticle precursors, polymers, and dopants are added to a solvent, heated and stirred, cooled, and then additives are added and stirred until homogeneous to obtain a photochromic dispersion material.

[0029] Furthermore, the heating temperature is 80-100℃.

[0030] Another object of the present invention is to provide a photochromic film comprising the above-mentioned photochromic dispersion material, wherein the preparation method of the photochromic film comprises the following steps:

[0031] A photochromic dispersion material is coated onto a substrate and then heated and dried to obtain a photochromic film.

[0032] Furthermore, the heating temperature is 60-120℃; the drying time is 3-30 minutes.

[0033] Furthermore, the photochromic nanoparticles account for 1-5% of the dry film mass of the photochromic film, and the average particle size is less than 30 nm.

[0034] Furthermore, the formation process of the photochromic film is based on a fully wet chemical coating method using solvents and materials that conforms to industrial standards, making it suitable for large-scale industrial production. The photochromic film can change its transmittance of visible and near-infrared light in response to changes in ultraviolet radiation intensity. As ultraviolet intensity increases, the photochromic film material changes from a transparent state to a colored state; as ultraviolet intensity decreases, the photochromic film material switches back from a colored state to a transparent state.

[0035] Furthermore, the all-wet chemical coating method includes, but is not limited to, blade coating, roll-to-roll coating, gravure coating, slot coating, flexographic printing, or spray coating.

[0036] Furthermore, the substrate is a rigid or flexible substrate, including but not limited to glass, polyethylene terephthalate (PET) film, polycarbonate (PC) film or sheet, polymethyl methacrylate (PMMA) sheet or acrylic adhesive film, and a primer or adhesive layer may be selectively used.

[0037] Furthermore, the dopant can modulate the response of the photochromic film to ultraviolet irradiation, particularly accelerating the recovery process under dark conditions.

[0038] Furthermore, the wetting agent is selected from one or more of polyacrylate or silicone-based surface additives, which can improve the wettability of the photochromic film, preferably BYK 361N or BYK 378.

[0039] Furthermore, the stabilizer is a light stabilizer, which can improve the stability of the photochromic film, and a hindered amine light stabilizer is preferred.

[0040] Furthermore, the dye can adjust the color of the photochromic film, preferably carbon black.

[0041] Furthermore, the photochromic film is protected by at least one protective layer. The functions of the protective layer include, but are not limited to, weather protection, scratch resistance, color adjustment, or ultraviolet absorption.

[0042] Furthermore, the photochromic film can be peeled off from the substrate to obtain an independent film containing only the photochromic layer.

[0043] Furthermore, the photochromic film can be detached from the substrate using an adhesive film to obtain a multilayer film comprising at least an adhesive layer and a photochromic layer.

[0044] Furthermore, the photochromic film exhibits at least a 15% change in solar energy transmission between the colored and transparent states, accompanied by at least a 15% change in visible light transmission.

[0045] Another object of the present invention is to provide the above-mentioned photochromic film as an adaptive dimming smart window film for adaptive sunlight and solar thermal management, wherein the amount of transmitted visible and near-infrared light depends on the outdoor ultraviolet intensity.

[0046] Furthermore, the adaptive dimming smart window film includes one or more photochromic layers and can be mass-produced industrially.

[0047] Furthermore, the method of using the adaptive dimming smart window film includes: after adding an adhesive layer during processing, it can be adhered to other substrates, including but not limited to glass, polycarbonate, or polymethyl methacrylate. Therefore, it can also be integrated into the cavity of a multi-layered window.

[0048] Furthermore, the method of using the adaptive dimming smart window film also includes: directly coating it onto a substrate with good adhesion, and the resulting panel can be directly used as a smart window or as part of a multi-layer window.

[0049] Furthermore, the method of using the adaptive dimming smart window film also includes: when preparing a self-supporting film without an adhesive layer, the film can be sandwiched between two window materials, including but not limited to glass, polycarbonate or polymethyl methacrylate.

[0050] The present invention has the following beneficial effects:

[0051] (1) This invention relates to a photochromic dispersion material and its preparation method, wherein photochromic nanoparticles are formed and dispersed from a precursor in a solvent. The photochromic dispersion material contains a polymer and a solvent, wherein the solvent is an industrially acceptable solvent, enabling the photochromic dispersion material to be processed on a large scale. Furthermore, in the prior art, supersaturation generally occurs during the drying process, and the formation and embedding of nanoparticles require two orthogonal solvents. In contrast, the photochromic dispersion material of this invention forms and disperses photochromic nanoparticles in a solvent. The solvent for dissolving the precursor and polymer does not need to rely on two orthogonal solvents, and can even be the same solvent. It does not require the solubility difference between the precursor solvent and the polymer to form and disperse the photochromic nanoparticles.

[0052] (2) This invention describes a thin film formation process in which a photochromic dispersion material is coated onto a rigid or flexible substrate and then subsequently dried. While standalone thin films are still possible, the photochromic thin film material may comprise a multilayer structure including at least a substrate and a photochromic layer. This allows for further processing of the film for smart window applications, including renovation applications with adhesive layers, coated panels with good adhesion, and lamination of the photochromic thin film material.

[0053] (3) The dopants added in this invention can improve the speed at which the smart window film is restored from a colored state to a transparent state. For example, during the photochromic reaction, some of the photoelectrons generated by WO3 are captured by its own oxygen vacancies, forming W 5+ The ions, and another part of them were Cu 2+ Cu absorption + During the fading process, Cu + It is an unstable intermediate valence state, and is more easily oxidized by oxygen in the air to form Cu. 2+ Electrons from W 5+ Oxygen vacancies on the complex surface are transferred to the generated Cu 2+ On the ions, it promotes the fading process.

[0054] (4) This invention discloses an adaptive dimming smart window film, which is composed of a polymer embedded with photochromic nanoparticles. This smart window film exhibits photochromic properties: under sunlight, the initially colorless and transparent film displays a blue hue and strong absorption in the near-infrared band, while maintaining high transmittance in the visible light band; under dark conditions, the film returns to a transparent state. Between the colored and transparent states, the change in solar transmittance exceeds 15%, and the change in visible light transmittance also exceeds 15%. Furthermore, the photochromic nanoparticles of this invention are embedded in the polymer. The polymer regulates the nucleation process by encapsulating the nanoparticle precursor and dispersing it in discrete compartments, thereby controlling particle growth and preventing particle aggregation. This allows for the simple and effective acquisition of highly dispersed small-sized nanoparticles in the composite film.

[0055] (5) The present invention adds wetting agents, stabilizers and other additives. The wetting agent has hydrophilic groups and lipophilic groups. When the surfactant is prepared into a solution, the surfactant molecules on its surface tend to oriented the hydrophilic groups toward the aqueous phase and the lipophilic groups toward the air phase, forming a thin film on the liquid surface to improve the wettability of the solution. The stabilizer can shield or absorb the energy of ultraviolet rays, prevent or delay the photoaging process, and extend the service life of polymer products. In addition, the polymer, photochromic nanoparticles, dopants and wetting agents and stabilizers of the present invention can obtain highly dispersed small-sized nanoparticles with fast response speed, good film-forming effect and long service life. Therefore, they have a synergistic effect and jointly improve the performance of the film.

[0056] (6) The formation process of the adaptive dimming smart window film of the present invention is based on a fully wet chemical coating method using solvents and materials that meet industrial standards. It is environmentally friendly and non-toxic, and suitable for large-scale industrial production. Attached Figure Description

[0057] Figure 1 A reduced-size image and a TEM image of the photochromic thin film prepared in Application Example 1 are shown;

[0058] in,

[0059] Figure 1 (a) shows a reduced-size image of the photochromic film prepared in Application Example 1;

[0060] Figure 1 (b) shows a TEM image of the photochromic thin film prepared using Example 1.

[0061] Figure 2 The colored and transparent state spectra of the photochromic thin film prepared in Application Example 1 are shown;

[0062] in,

[0063] Figure 2 (a) shows the coloring of the photochromic film prepared in Example 1 under ultraviolet irradiation;

[0064] Figure 2 (b) shows the reduction of the photochromic film prepared in Example 1 in the dark.

[0065] Figure 3 A schematic diagram of the photochromic film prepared in Application Example 1 being bonded to a substrate is shown.

[0066] Figure 4 The coloring and transparent states of the photochromic film prepared in Application Example 2, with and without PDMS topcoat, are shown.

[0067] in,

[0068] Figure 4 (a) shows a comparison of the colored and transparent states of the photochromic film prepared in Application Example 2 with and without PDMS topcoat;

[0069] Figure 4 (b) shows a schematic diagram of the structure of the photochromic film prepared in Application Example 2 covered with PDMS topcoat.

[0070] Figure 5 The transmission spectrum of the photochromic thin film prepared in Application Example 3 is shown.

[0071] Figure 6 A physical image of the photochromic thin film prepared in Application Example 4 is shown.

[0072] Figure 7 A physical image of the photochromic thin film prepared in Application Example 5 is shown.

[0073] Figure 8 The transmission spectrum of the photochromic thin film prepared in Application Example 6 is shown.

[0074] Figure 9 The transmission spectrum of the photochromic thin film prepared in Application Example 7 is shown;

[0075] in,

[0076] Figure 9 (a) shows that in Application Example 7, without the addition of dopants, the thin film in the colored state has the same coloring rate and the same transmittance;

[0077] Figure 9 (b) shows that in application example 7, the film fades at a much lower rate than the film with added dopant.

[0078] Figure 10 The transmission spectrum of the photochromic thin film prepared in Application Example 8 is shown;

[0079] in,

[0080] Figure 10 (a) shows the coloring of the photochromic film prepared in Example 8 under ultraviolet irradiation;

[0081] Figure 10 (b) shows the reduction of the photochromic film prepared in Example 8 in the dark. Detailed Implementation

[0082] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0083] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0084] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0085] The polymethyl methacrylate used in this embodiment of the invention has a molecular weight of 120,000 g / mol and was purchased from Sigma-Aldrich, Germany.

[0086] The polyamic acid used in this embodiment of the invention has a molecular weight of 1800 g / mol and was purchased from Sigma-Aldrich, Germany.

[0087] In the embodiments of this invention, "parts" refers to parts by mass.

[0088] Example 1

[0089] A photochromic dispersion material, wherein the photochromic dispersion material is composed of PMMA, WO3 nanoparticles, cuprous chloride (CuCl) and BYK 378.

[0090] The preparation method of the above-mentioned photochromic dispersion material includes the following steps:

[0091] S1. Add PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), then place it on a hot plate at 140°C and stir for 2 hours to obtain solution 1, which has a viscosity of about 1 Pa·s.

[0092] S2. Add tungsten chloride (WCl6) and cuprous chloride (CuCl) to ethyl lactate (WCl6:ethyl lactate = 1:5.15, m / m; CuCl6:ethyl lactate = 1:5.15, m / m). + :W 6+ =4:25, n / n), then place on a hot plate at 90℃ and stir for 2 hours to obtain solution 2;

[0093] S3. Mix solution 1 and solution 2 (solution 1:solution 2 = 1:0.0885, m / m), stir until all bubbles disappear, then add 0.5wt% BYK 378, stir evenly, and obtain photochromic dispersion material.

[0094] Example 2

[0095] A photochromic dispersion material, wherein the photochromic dispersion material is composed of PMMA, WO3 nanoparticles, CuCl and BYK 378.

[0096] The preparation method of the above-mentioned photochromic dispersion material includes the following steps:

[0097] S1. Add PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), then place it on a hot plate at 140°C and stir for 2 hours to obtain solution 1;

[0098] S2. Add WCl6 and CuCl to ethyl lactate (WCl6:ethyl lactate = 1:5.15, m / m; CuCl6:ethyl lactate = 1:5.15, m / m). + :W 6+ =4:25, n / n), stir the solution at room temperature until a transparent blue solution is obtained, to obtain solution 2;

[0099] S3. Mix solution 1 and solution 2 (solution 1:solution 2 = 1:0.0885, m / m), stir until all bubbles disappear, then add 0.5wt% BYK 378, stir evenly, and obtain photochromic dispersion material.

[0100] Example 3

[0101] A photochromic dispersion material, wherein the photochromic dispersion material is composed of PMMA, WO3 nanoparticles, CuCl and BYK 378.

[0102] The preparation method of the above-mentioned photochromic dispersion material includes the following steps:

[0103] 2.28 g PMMA, 10 g ethyl lactate, 164 mg WCl6 and 6.5 mg CuCl were mixed and stirred at 90 °C for 5 h. After cooling, 0.15 wt% BYK 378 was added and stirred at room temperature until the bubbles completely disappeared to obtain the photochromic dispersion material.

[0104] Example 4

[0105] A photochromic dispersion material, wherein the photochromic dispersion material is composed of PMMA, WO3 nanoparticles, CuCl and BYK 378.

[0106] The preparation method of the above-mentioned photochromic dispersion material includes the following steps:

[0107] S1. Add PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), then place it on a hot plate at 140°C and stir for 2 hours to obtain solution 1;

[0108] S2. Add WCl6 and CuCl to ethyl lactate (WCl6:ethyl lactate = 1:5.15, m / m; CuCl6:ethyl lactate = 1:5.15, m / m). + :W 6+ =4:25, n / n), then place on a hot plate at 90℃ and stir for 2 hours to obtain solution 2;

[0109] S3. Mix solution 1 and solution 2 (solution 1:solution 2 = 1:0.0885, m / m), stir until all bubbles disappear, then add 0.5wt% BYK 378, stir evenly, and obtain photochromic dispersion material.

[0110] Example 5

[0111] A photochromic dispersion material, wherein the photochromic dispersion material is composed of PMMA, polyamic acid (PAA), WO3 nanoparticles, CuCl and BYK 378.

[0112] The preparation method of the above-mentioned photochromic dispersion material includes the following steps:

[0113] S1. PMMA is added to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), and then stirred on a hot plate at 140°C for 2 hours to obtain a PMMA solution; PAA is added to ethyl lactate (PAA: ethyl lactate = 1:3, m / m), and then stirred on a hot plate at 90°C for 2 hours to obtain a PAA solution; the PMMA solution and PAA solution (PMMA solution: PAA solution = 9:1, m / m) are mixed to obtain solution 1;

[0114] S2. Add WCl6 and CuCl to ethyl lactate (WCl6:ethyl lactate = 1:5.15, m / m; CuCl6:ethyl lactate = 1:5.15, m / m). + :W 6+ =4:25, n / n), then place on a hot plate at 90°C and stir for 2 hours until a transparent blue solution is obtained, thus obtaining solution 2;

[0115] S3. Mix solution 1 and solution 2 (solution 1:solution 2 = 1:0.0221, m / m), stir until all bubbles disappear, then add 0.5wt% BYK 361N, stir evenly, and obtain photochromic dispersion material.

[0116] Example 6

[0117] A photochromic dispersion material, wherein the photochromic dispersion material is composed of PMMA, WO3 nanoparticles, CuCl and BYK 378.

[0118] The preparation method of the above-mentioned photochromic dispersion material includes the following steps:

[0119] S1. Add PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), then place it on a hot plate at 140°C and stir for 2 hours to obtain solution 1;

[0120] S2. Add WCl6 and CuCl to ethyl lactate (WCl6:ethyl lactate = 1:5.15, m / m; CuCl6:ethyl lactate = 1:5.15, m / m). + :W 6+ =4:25, n / n), then place on a hot plate at 90℃ and stir for 2 hours to obtain solution 2;

[0121] S3. Mix solution 1 with solution 2 (solution 1:solution 2 = 1:0.1106, m / m), stir until all bubbles disappear, then add 0.5 wt% BYK 378, stir evenly to obtain intermediate product 1; add hindered amine light stabilizer (HALS) Chimasorb 944 to ethyl lactate (Chimasorb 944:ethyl lactate = 1:20, m / m), stir evenly to obtain Chimasorb 944 solution; mix the Chimasorb 944 solution with intermediate product 1 (Chimasorb 944:ethyl lactate = 1:20, m / m). 944 solution: intermediate product 1 = 3:500, m / m) are mixed to obtain intermediate product 2; carbon black is added to ethyl lactate (carbon black: ethyl lactate = 1:2.5, m / m) and stirred evenly to obtain carbon black solution; the carbon black solution is mixed with the intermediate product 2 (carbon black solution: intermediate product 2 = 87:10000, m / m) to obtain photochromic dispersion material.

[0122] Example 7

[0123] A photochromic dispersion material. The difference between this embodiment and Embodiment 1 is that CuCl is not added in step S2, while the dosage of other components and the preparation method are the same as in Embodiment 1.

[0124] Example 8

[0125] A photochromic dispersion material. The difference between this embodiment and Embodiment 1 is that in step S2, the dopant CuCl is replaced with FeCl3 at the same molar mass. The amounts of other components and the preparation method are the same as in Embodiment 1.

[0126] Application Example 1

[0127] This application example describes the preparation of a photochromic film based on polymethyl methacrylate (PMMA) containing embedded tungsten trioxide (WO3) nanoparticles and copper doped onto an acrylic pressure-sensitive adhesive, using a single solvent.

[0128] A photochromic thin film, comprising the photochromic dispersion material of Example 1, wherein the preparation method of the photochromic thin film comprises the following steps:

[0129] At room temperature, using a gap size of 120 μm and a coating speed of 1 m / min, the photochromic dispersion material of Example 1 was coated onto an acrylic pressure-sensitive adhesive to form a film. Then, it was placed on a hot plate at 90°C and dried for 10 min using a hot air gun at 90°C on top to obtain the photochromic film.

[0130] The dry film thickness of the photochromic film is 40 μm, and the mass of WO3 nanoparticles is 4% of the dry film mass of the photochromic film.

[0131] Figure 1 A reduced-size image and a TEM image of the photochromic thin film prepared in Application Example 1 are shown;

[0132] in,

[0133] Figure 1 (a) shows a reduced-size image of the photochromic film prepared in Application Example 1; the thickness of the photochromic film is shown in the figure.

[0134] Figure 1 (b) shows a TEM image of the photochromic film prepared in Example 1; the image shows WO3 nanoparticles with a size of 2-20 nm.

[0135] Figure 2 The colored and transparent state spectra of the photochromic thin film prepared in Application Example 1 are shown;

[0136] in,

[0137] Figure 2 (a) shows the coloring of the photochromic film prepared in Example 1 under ultraviolet irradiation;

[0138] Figure 2 (b) shows the reduction of the photochromic film prepared in Example 1 in the dark;

[0139] Depend on Figure 2 It can be seen that when the strength is 5mW / m 2 After 15 minutes of irradiation with 365nm LED light, the transmittance of the photochromic film prepared in Example 1 changed, with the intensity comparable to the ultraviolet radiation of sunlight. The visible light transmittance T of this photochromic film... visThe solar transmittance T decreased from 90% in the transparent state to 40% in the colored state. sol The percentage of the transparent state decreased from 85% to 36% of the colored state.

[0140] Figure 3 A schematic diagram of the photochromic film prepared in Application Example 1 being bonded to a substrate is shown; after removing the backing from the uncoated side of the adhesive layer, the photochromic film can be adhered to a glass or polymer plate.

[0141] Application Example 2

[0142] This application example describes the preparation of a photochromic film on polymethyl methacrylate (PMMA) with a protective outer coating on a polycarbonate substrate, the photochromic film being embedded with Cu-doped tungsten trioxide (WO3) nanoparticles.

[0143] A photochromic thin film, comprising the photochromic dispersion material of Example 2, wherein the preparation method of the photochromic thin film comprises the following steps:

[0144] At room temperature, using a gap size of 120 μm and a coating speed of 1 m / min, the photochromic dispersion material of Example 2 was coated onto a polycarbonate film substrate using a doctor blade to form a film. The film was then placed on a hot plate at 90°C and dried with a hot air gun for 10 min to obtain the photochromic film.

[0145] The photochromic film has a dry film thickness of 40 μm, and the WO3 nanoparticles account for 4% of the dry film mass. After cooling and allowing the photochromic film to air dry at room temperature for one day, the film exhibits good adhesion to the PC substrate, as verified by the cross-hatch tape test according to ASTM D3359 standard 4B classification.

[0146] Figure 4 The coloring and transparent states of the photochromic film prepared in Application Example 2, with and without PDMS topcoat, are shown.

[0147] in,

[0148] Figure 4 (a) shows a comparison of the colored and transparent states of the photochromic film prepared in Application Example 2 with and without PDMS topcoat;

[0149] Figure 4 (b) shows a schematic diagram of the structure of the photochromic film prepared in Application Example 2 covered with PDMS topcoat;

[0150] Depend on Figure 4It was found that a silicone protective layer was prepared by mixing silicone components at a 1:10 ratio using the Silgard 184 silicone elastomer kit. Then, a photochromic dispersion material was coated onto the protective layer using a 14μm wire rod and cured at 80°C for 2 hours. The color-changing and fading properties of the coating were not affected by the PDMS protective layer.

[0151] Application Example 3

[0152] This application example describes the preparation of an adhesive photochromic film with a scratch-resistant protective layer, based on a polymethyl methacrylate (PMMA) photochromic film in which copper-doped tungsten trioxide (WO3) nanoparticles are embedded, using a one-step mixing method, and topped with a scratch-resistant hard coating with ultraviolet absorption properties.

[0153] A photochromic thin film, comprising the photochromic dispersion material of Example 3, wherein the preparation method of the photochromic thin film comprises the following steps:

[0154] The photochromic dispersion material of Example 3 was coated onto a 100 μm thick PET substrate to form a film, and then dried on a hot plate at 90°C for 10 min to obtain the photochromic film.

[0155] The photochromic film has a dry film thickness of 40 μm. An acrylic adhesive layer is adhered to the surface of the photochromic film to allow it to be peeled off from the substrate, thereby obtaining an adhesive smart window film.

[0156] UV-curable aliphatic urethane acrylate Ebecryl 225 was mixed with ethyl acetate (Ebecryl 225:ethyl acetate = 2:1, m / m), then 7 wt% Omnirad TPO photoinitiator and 1.5 wt% Tinuvin 328 UV absorber were added to obtain an outer coating. The outer coating was applied to the top of the photochromic film prepared in Application Example 3 using a 14 μm wire rod and a coating speed of 2.5 m / min, and then coated with an UV absorber of 60 W / cm². 2 Cured with ultraviolet light for 10 seconds.

[0157] After 20 minutes, 1mW / cm 2 After irradiation with ultraviolet light, a photochromic film with a partially ultraviolet-blocking protective layer was obtained, and its visible light transmittance decreased by only 5%, compared to a 26% decrease in the unprotected photochromic film. (At 10 mW / cm²) 2 Under ultraviolet radiation, the visible light transmittance of both decreased to 40%, indicating that the color change threshold changed due to the presence of the protective layer.

[0158] Figure 5The transmission spectrum of the photochromic thin film prepared in Application Example 3 is shown.

[0159] The photochromic film with a scratch-resistant hard coating passed the abrasion test according to ASTM D1044 standard. A rotating platform friction tester showed a 4% increase in haze, while the photochromic film without an anti-scratch protective layer showed a 31% increase in haze.

[0160] Application Example 4

[0161] This application example describes the process of preparing photochromic films on a pilot roll-to-roll production line.

[0162] A photochromic thin film, comprising the photochromic dispersion material of Example 4, wherein the preparation method of the photochromic thin film comprises the following steps:

[0163] On a 40cm wide trough-type coating machine, at a coating speed of 3m / min, the photochromic dispersion material of Example 4 was coated onto a PET substrate to form a film. Then, it was placed in the drying zone of a 10m long hot air oven at 100°C and dried for 200s to obtain the photochromic film.

[0164] Figure 6 A physical image of the photochromic thin film prepared in Application Example 4 is shown.

[0165] The viscosity of the photochromic dispersion material is 1 Pa·s, which meets the requirements for uniform coating on roll-to-roll machines; the coating speed is set to 3 m / min to ensure production efficiency. The coating should be applied to a suitable substrate according to the actual application requirements; a PET substrate can be used, or it can be directly coated onto a pressure-sensitive adhesive.

[0166] Application Example 5

[0167] This application example describes the preparation of a photochromic film on a glass plate consisting of a mixture of polymethyl methacrylate (PMMA) and polyamic acid (PAA).

[0168] A photochromic film, comprising the photochromic dispersion material of Example 5, wherein the preparation method of the photochromic film comprises the following steps:

[0169] At room temperature, using a gap size of 120 μm and a coating speed of 1 m / min, the photochromic dispersion material of Example 5 was coated onto a 4 mm float glass plate to form a thin film by scraping. Then, it was placed on a hot plate at 90°C and dried for 10 min using a hot air gun at 90°C on top to obtain the photochromic film.

[0170] The dry film thickness of the photochromic film is 40 μm, and the mass of WO3 nanoparticles is 1% of the dry film mass of the photochromic film.

[0171] Figure 7 A physical image of the photochromic thin film prepared in Application Example 5 is shown.

[0172] The photochromic film exhibits strong adhesion to the glass plate, meeting Class 2B adhesion standards according to ASTM D3359. Under simulated sunlight, the visible light transmittance T of the photochromic film... vis It decreased from 90% to 75%.

[0173] Application Example 6

[0174] This application example describes the preparation of a photochromic film based on polymethyl methacrylate (PMMA) coated on a PMMA substrate. The smart window film has embedded copper-doped tungsten trioxide (WO3) nanoparticles and additional pigments and light stabilizers added to the PMMA substrate.

[0175] A photochromic thin film, comprising the photochromic dispersion material of Example 6, wherein the preparation method of the photochromic thin film comprises the following steps:

[0176] At room temperature, using a gap size of 120 μm and a coating speed of 1 m / min, the photochromic dispersion material of Example 6 was coated onto a 2 mm thick PMMA plate using a doctor blade to form a film. The film was then placed on a hot plate at 60°C and dried with a hot air gun at 80°C for 20 min to obtain the photochromic film.

[0177] The photochromic film has a dry film thickness of 40 μm, and the WO3 nanoparticles account for 5% of the dry film mass. After cooling and further drying under ambient conditions for 1 day, the photochromic film exhibits good adhesion to the PC substrate and passes the ASTM D3359 Class 2B adhesion test.

[0178] Figure 8 The transmission spectrum of the photochromic thin film prepared in Application Example 6 is shown.

[0179] Depend on Figure 8 It can be seen that the transmittance of the photochromic film prepared in Example 6 decreased by 15% under the full solar spectrum. After simulated sunlight irradiation, the transmittance changed by 31%, which is 42% compared with the photochromic film without carbon black and light stabilizer.

[0180] Application Example 7

[0181] A photochromic film, comprising the photochromic dispersion material of Example 7, wherein the preparation method of the photochromic film is the same as that of Application Example 1.

[0182] Figure 9 The transmission spectrum of the photochromic thin film prepared in Application Example 7 is shown;

[0183] in,

[0184] Figure 9 (a) shows that in Application Example 7, without the addition of dopants, the thin film in the colored state has the same coloring rate and the same transmittance;

[0185] Figure 9 (b) shows that in application example 7, the film fading rate is much lower than that of the film with added dopant;

[0186] Depend on Figure 9 It can be seen that a strength of 100mW / m 2 After 15 seconds of irradiation with 365nm LED light, the visible light transmittance T of the photochromic thin film prepared in Example 7 was measured. vis The solar transmittance T decreased from 89% in the transparent state to 50% in the colored state. sol The photochromic film decreased from 88% in the transparent state to 55% in the colored state. After the ultraviolet lamp was removed for 2 hours, the photochromic film recovered from the colored state to the transparent state at a much slower rate than the film with added dopants.

[0187] Application Example 8

[0188] A photochromic film, comprising the photochromic dispersion material of Example 8, wherein the preparation method of the photochromic film is the same as that of Application Example 1.

[0189] Figure 10 The transmission spectrum of the photochromic thin film prepared in Application Example 8 is shown;

[0190] in,

[0191] Figure 10 (a) shows the coloring of the photochromic film prepared in Example 8 under ultraviolet irradiation;

[0192] Figure 10 (b) shows the reduction of the photochromic film prepared in Example 8 in the dark;

[0193] Depend on Figure 10 It can be seen that a strength of 100mW / m 2 After irradiation with an ultraviolet lamp for 60 seconds, the visible light transmittance T of the photochromic thin film prepared in Example 8 was measured. vis The solar transmittance T decreased from 86% in the transparent state to 60% in the colored state. sol The photochromic film decreased from 85% in the transparent state to 65% in the colored state. After the ultraviolet lamp was removed, the photochromic film returned to the transparent state from the colored state.

[0194] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0195] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A photochromic dispersion material, characterized in that, The photochromic dispersion material comprises photochromic nanoparticles, a polymer, and a solvent; in, The photochromic nanoparticles are formed from photochromic nanoparticle precursors and dispersed during and after mixing in a solvent. The photochromic dispersion material further includes a dopant, wherein the dopant is CuCl; The photochromic nanoparticles are wide-bandgap semiconductor materials, which are selected from one or more of titanium dioxide, tungsten trioxide, or molybdenum trioxide. The polymer is polymethyl methacrylate; The solvent is ethyl lactate; The photochromic dispersion material further includes additives, which are selected from one or more of wetting agents, stabilizers or dyes; The preparation method of the photochromic dispersion material includes the following steps: S1. Add the polymer to ethyl lactate, heat and stir to obtain solution 1; S2. Add the photochromic nanoparticle precursor and dopant to ethyl lactate, and stir at room temperature or under heating conditions to obtain solution 2. S3. Mix the solutions 1 and 2 together, then add the additives and stir until homogeneous to obtain a photochromic dispersion material; or Photochromic nanoparticle precursors, polymers, and dopants were added to ethyl lactate, heated and stirred, cooled, and then additives were added and stirred until homogeneous to obtain a photochromic dispersion material.

2. A photochromic thin film, characterized in that, Including the photochromic dispersion material of claim 1, the method for preparing the photochromic thin film includes the following steps: A photochromic dispersion material is coated onto a substrate and then heated and dried to obtain a photochromic film.

3. The application of the photochromic film of claim 2 as an adaptive dimming smart window film in adaptive sunlight and solar thermal management.

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