Photochromic dispersing material, preparation method thereof and self-adaptive dimming intelligent window film prepared from photochromic dispersing material

Abstract

The invention relates to a photochromic dispersion material. The photochromic dispersion material comprises photochromic nanoparticles, a polymer and a solvent, wherein the photochromic nano-particles are formed by photochromic nano-particle precursors, and are dispersed in a mixing process in a solvent and after mixing; the photochromic nanoparticles are formed in a non-orthogonal solvent or a single solvent. The solvent is an industrially acceptable solvent so that the photochromic dispersion material can be processed on a large scale. The invention further relates to a photochromic film which has the photochromic characteristic that under the irradiation of sunlight, the film which is colorless and transparent initially shows a blue hue and has strong absorption in a near-infrared band, but the high transmittance is still kept in a visible light band; and the film can recover to a transparent state under a dark condition. The sunlight transmission change of the intelligent window film between a colored state and a transparent state is greater than 15%, and meanwhile, the visible light transmittance change is greater than 15%.

Description

Technical Field

[0001] The invention relates to the field of photochromic materials, and in particular to a photochromic dispersion material and a preparation method thereof, and an adaptive dimming smart window film made of the same. Background Art

[0002] Improving energy efficiency and reducing carbon emissions are crucial. Windows are considered the least energy efficient part of a building's facade due to radiative heat dissipation in winter and solar radiation warming in summer. To improve energy efficiency and visible light comfort in buildings, smart windows are gaining attention.

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

[0004] Many existing patents for photochromic window films, such as WO2008043853A2, CN217001448U, CN106218172A, are based on organic molecules with photochromic properties. Based on the literature research of the organic molecules mentioned in these patents, it can be concluded that all of these molecules only change their transmission / absorption in a narrow band, mainly in the visible light range. This leads to the regulation of visible light, not the control of temperature; and they all have some shortcomings.

[0005] In addition, photochromic materials that cover most of the solar spectrum are usually inorganic materials, such as tungsten oxide (WO3). The main challenge of this material is to make it into transparent films. Tungsten oxides described in the literature have excellent photochromic properties and are usually based on films or nanoparticles that are scattering in both transparent and color-changing states. The synthesis of nanoparticles small enough (less than 50nm in diameter) to obtain low-scattering materials requires expensive and non-scalable methods, such as solvothermal synthesis combined with ball milling.

[0006] In addition, WO2024007275A1 describes a film having low scattering and significant sunlight regulation properties, however, the film has the following defects: First, its processing method requires two different orthogonal solvents with large polarity differences, which brings inconvenience to industrial production, and the method described therein uses hazardous chemicals such as dimethylformamide, which is a solvent not suitable for large-scale industrial production. Secondly, during the film formation process, photochromic inorganic nanoparticles are formed and dispersed when the precursor solution is dried. The choice of solvent makes the solubility of the formed photochromic inorganic nanoparticles in the precursor solvent greater than that of the polymer, so the nanoparticles are formed and dispersed by supersaturated drying during the film formation process; thirdly, the film it claims is an independent film consisting only of a photochromic layer, which is prepared by coating a sol-gel material on 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 produced industrially on a low-cost and large scale to overcome the above problems. Summary of the invention

[0008] Based on the above defects, the present invention discloses a photochromic dispersion material and an adaptive dimming smart window film made of the photochromic dispersion material. The photochromic dispersion material includes photochromic nanoparticles, a polymer and a solvent; the adaptive dimming smart window film is a photochromic nanoparticle embedded in a polymer. The formation process of the adaptive dimming smart window film is based on a full wet chemical coating method of solvents and materials that meet industrial standards, which is suitable for large-scale industrial production. Under ultraviolet irradiation, the smart window film changes from a transparent state to a colored state; in the dark, the smart window film will return to a transparent state.

[0009] An 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 a photochromic nanoparticle precursor and dispersed during and after mixing in a solvent;

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

[0013] Furthermore, the photochromic dispersion material further includes a dopant, and the dopant 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 further comprises an additive, wherein the additive is selected from one or more of a wetting agent, a stabilizer or a dye; the additive can improve the wettability, stability and / or color of the coating.

[0017] Furthermore, the photochromic nanoparticles are wide bandgap semiconductor materials, and the wide bandgap semiconductor materials 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 not included in 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, wherein one solution comprises the following steps:

[0021] S1, adding the polymer to the solvent, heating and stirring, to obtain solution 1;

[0022] S2, adding a photochromic nanoparticle precursor and a dopant into a solvent, stirring at room temperature or under heating conditions, to obtain a solution 2;

[0023] S3, blending the solution 1 and the solution 2, then adding additives, and stirring evenly 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°C.

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

[0027] Another solution includes the following steps:

[0028] The photochromic nanoparticle precursor, polymer and dopant are added into the solvent, heated and stirred, and after cooling, additives are added and stirred evenly to obtain the photochromic dispersed material.

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

[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] The photochromic dispersion material is coated on a substrate, heated and dried to obtain a photochromic film.

[0032] Furthermore, the heating temperature is 60-120° C.; and the drying time is 3-30 min.

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

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

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

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

[0037] Furthermore, the dopant can adjust the response of the photochromic film to ultraviolet radiation, in particular, accelerate the recovery process under dark conditions.

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

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

[0040] Furthermore, the dye can adjust the color of the photochromic film, and is 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] Further, the photochromic film can be released from the substrate by using an adhesive film to obtain a multilayer film including at least an adhesive layer and a photochromic layer.

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

[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 heat management, wherein the amount of transmitted visible light 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 industrially produced on a large scale.

[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-layer window.

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

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

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

[0051] (1) The present invention relates to a photochromic dispersion material and a preparation method thereof, in which photochromic nanoparticles are formed and dispersed from a precursor in a solvent. The photochromic dispersion material contains a polymer and a solvent, and the solvent is an industrially accepted solvent, so that the photochromic dispersion material can be processed on a large scale. In addition, the prior art generally supersaturates during the drying process, and the formation and embedding of nanoparticles require two orthogonal solvents, while the photochromic dispersion material of the present invention forms and disperses photochromic nanoparticles in a solvent, and the solvent for dissolving the precursor and the polymer does not need to rely on two orthogonal solvents, and can even be the same solvent, and does not need to form and disperse the photochromic nanoparticles through the solubility difference between the precursor solvent and the polymer.

[0052] (2) The present invention describes a thin film formation process in which a photochromic dispersion material is coated onto a rigid or flexible substrate followed by subsequent drying. While a stand-alone film is still possible, the photochromic thin film material may include a multilayer structure of at least a substrate and a photochromic layer. This allows for further processing of the film for use in smart window applications, including renovation applications with an adhesive layer, coated panels with good adhesion, and lamination of photochromic thin film materials.

[0053] (3) The dopant added in the present invention can increase the speed at which the smart window film is restored from a colored state to a transparent state. For example, during the photochromic reaction, part of the photoelectrons generated by WO3 are captured by its own oxygen vacancies to form W 5+ ions, and the other part is Cu 2+ Absorption of Cu + 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+ , the electrons from W 5+ The oxygen vacancies occupied by the complex surface are transferred to the generated Cu 2+ ions, promoting the fading process.

[0054] (4) The present invention discloses an adaptive dimming smart window film, which is composed of a polymer embedded with photochromic nanoparticles. The smart window film has photochromic properties: under sunlight, the initially colorless and transparent film will show a blue hue and have strong absorption in the near-infrared band, but the visible light band still maintains a high transmittance; under dark conditions, the film will return to a transparent state. Between the colored and transparent states, the solar transmittance changes by more than 15%, and the visible light transmittance also changes by more than 15%. In addition, the photochromic nanoparticles of the present invention are embedded in the polymer, and the polymer regulates the nucleation process by encapsulating the nanoparticle precursor and dispersing it in discrete compartments, thereby controlling the growth of the particles and preventing particle agglomeration, and highly dispersed small-sized nanoparticles can be obtained in the composite film simply and effectively.

[0055] (5) The present invention adds additives such as wetting agents and stabilizers. The wetting agent has a hydrophilic group and a lipophilic group. When the surfactant is prepared into a solution, the active agent molecules on its surface tend to turn the hydrophilic group toward the water phase and the lipophilic group 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 process of photoaging, and extend the service life of high molecular 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 and have a faster response speed, good film-forming effect and a longer service life, so they have a synergistic effect and jointly improve the film performance.

[0056] (6) The formation process of the adaptive dimming smart window film of the present invention is a full wet chemical coating method based on solvents and materials that meet industrial standards. It is environmentally friendly and non-toxic and suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The reduced image and TEM image of the photochromic film prepared in Application Example 1 are shown;

[0058] in,

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

[0060] Figure 1 (b) shows the TEM image of the photochromic film prepared in Application Example 1.

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

[0062] in,

[0063] Figure 2 (a) shows that the photochromic film prepared in Application Example 1 is colored under ultraviolet irradiation;

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

[0065] Figure 3 A schematic diagram showing the bonding of the photochromic film prepared in Application Example 1 to a substrate.

[0066] Figure 4 The colored state and transparent state of the photochromic film prepared in Application Example 2 without being covered with PDMS topcoat and with being covered with PDMS topcoat are shown;

[0067] in,

[0068] Figure 4 (a) shows the comparison between the colored state and the transparent state of the photochromic film prepared in Application Example 2 without being covered with PDMS topcoat and with being covered with 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 film prepared in Application Example 3 is shown.

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

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

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

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

[0075] in,

[0076] Fig. 9 (a) shows that in Application Example 7, no dopant is added, and in the colored state, the film has the same coloring speed and the same transmittance;

[0077] Fig. 9 (b) shows that in Application Example 7, the fading speed of the film is much lower than that of the film with added dopants.

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

[0079] in,

[0080] Fig.10 (a) shows that the photochromic film prepared in Application Example 8 is colored under ultraviolet irradiation;

[0081] Fig.10 (b) shows the reduction of the photochromic film prepared in Application Example 8 in the dark. DETAILED DESCRIPTION

[0082] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0083] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0084] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

[0085] The molecular weight of the polymethyl methacrylate in the embodiment of the present invention is 120000 g / mol, and it is purchased from Sigma-Aldrich, Germany.

[0086] The molecular weight of the polyamic acid in the embodiment of the present invention is 1800 g / mol, and it is purchased from Sigma-Aldrich, Germany.

[0087] The "parts" in the embodiments of the present invention refer to parts by mass.

[0088] Example 1

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

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

[0091] S1, adding PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), and then placing on a hot plate at 140° C. and stirring for 2 h to obtain solution 1, the viscosity of which is 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; Cu + :W 6+ =4:25, n / n), and then placed on a hot plate at 90° C. and stirred for 2 h to obtain solution 2;

[0093] S3. The solution 1 and the solution 2 (solution 1:solution 2=1:0.0885, m / m) were mixed and stirred until all bubbles disappeared, and then 0.5 wt % of BYK 378 was added and stirred evenly to obtain a photochromic dispersion material.

[0094] Example 2

[0095] A photochromic dispersion material consists of PMMA, WO3 nanoparticles, CuCl and BYK 378.

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

[0097] S1, adding PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), and then placing on a hot plate at 140° C. and stirring for 2 h to obtain solution 1;

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

[0099] S3. The solution 1 and the solution 2 (solution 1:solution 2=1:0.0885, m / m) were mixed and stirred until all bubbles disappeared, and then 0.5 wt % of BYK 378 was added and stirred evenly to obtain a photochromic dispersion material.

[0100] Example 3

[0101] A photochromic dispersion material consists of PMMA, WO3 nanoparticles, CuCl and BYK 378.

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

[0103] 2.28 g PMMA, 10 g ethyl lactate, 164 mg WCl6 and 6.5 mg CuCl were mixed, then 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 a photochromic dispersion material.

[0104] Example 4

[0105] A photochromic dispersion material consists of PMMA, WO3 nanoparticles, CuCl and BYK 378.

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

[0107] S1, adding PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), and then placing on a hot plate at 140° C. and stirring for 2 h to obtain solution 1;

[0108] S2, WCl6 and CuCl were added to ethyl lactate (WCl6: ethyl lactate = 1:5.15, m / m; Cu + :W 6+ =4:25, n / n), and then placed on a hot plate at 90° C. and stirred for 2 h to obtain solution 2;

[0109] S3. The solution 1 and the solution 2 (solution 1:solution 2=1:0.0885, m / m) were mixed and stirred until all bubbles disappeared, and then 0.5 wt % of BYK 378 was added and stirred evenly to obtain a photochromic dispersion material.

[0110] Example 5

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

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

[0113] S1, adding PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), and then placing it on a hot plate at 140° C. and stirring it for 2 hours to obtain a PMMA solution; adding PAA to ethyl lactate (PAA: ethyl lactate = 1:3, m / m), and then placing it on a hot plate at 90° C. and stirring it for 2 hours to obtain a PAA solution; mixing the PMMA solution with the PAA solution (PMMA solution: PAA solution = 9:1, m / m) to obtain a solution 1;

[0114] S2, WCl6 and CuCl were added to ethyl lactate (WCl6: ethyl lactate = 1:5.15, m / m; Cu + :W 6+ =4:25, n / n), and then placed on a hot plate at 90° C. and stirred for 2 h until a transparent blue solution was obtained to obtain solution 2;

[0115] S3. The solution 1 and the solution 2 (solution 1:solution 2=1:0.0221, m / m) were mixed and stirred until all bubbles disappeared, and then 0.5 wt % of BYK 361N was added and stirred evenly to obtain a photochromic dispersion material.

[0116] Example 6

[0117] A photochromic dispersion material consists of PMMA, WO3 nanoparticles, CuCl and BYK 378.

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

[0119] S1, adding PMMA to ethyl lactate (PMMA: ethyl lactate = 1:4, m / m), and then placing on a hot plate at 140° C. and stirring for 2 h to obtain solution 1;

[0120] S2, WCl6 and CuCl were added to ethyl lactate (WCl6: ethyl lactate = 1:5.15, m / m; Cu + :W 6+ =4:25, n / n), and then placed on a hot plate at 90° C. and stirred for 2 h to obtain solution 2;

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

[0122] Example 7

[0123] A photochromic dispersion material. The difference between this embodiment and embodiment 1 is that in step S2, CuCl is not added, and the amounts of other components and the preparation method are the same as those 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 molar mass of the dopant CuCl is replaced by FeCl3, and the amounts of other components and the preparation method are the same as those in embodiment 1.

[0126] Application Example 1

[0127] This application note describes the preparation of photochromic films based on polymethyl methacrylate (PMMA) embedded with tungsten trioxide (WO3) nanoparticles and doped with copper on an acrylic pressure sensitive adhesive, based on a single solvent.

[0128] A photochromic film comprises the photochromic dispersion material of embodiment 1, and a preparation method of the photochromic film comprises the following steps:

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

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

[0131] Figure 1 The reduced image and TEM image of the photochromic film prepared in Application Example 1 are shown;

[0132] in,

[0133] Figure 1 (a) shows a reduced 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 Application Example 1; the figure shows WO3 nanoparticles with a size of 2-20 nm.

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

[0136] in,

[0137] Figure 2 (a) shows that the photochromic film prepared in Application Example 1 is colored under ultraviolet irradiation;

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

[0139] Depend on Figure 2 It can be seen that when the intensity is 5mW / m 2 After irradiation with 365nm LED light for 15 minutes, the transmittance of the photochromic film prepared in Example 1 changes, and the intensity is equivalent to the ultraviolet intensity of sunlight. vis, from 90% in the transparent state to 40% in the colored state; the solar transmittance T sol , from 85% in the transparent state to 36% in the colored state.

[0140] Figure 3 A schematic diagram showing the bonding of the photochromic film prepared in Application Example 1 to a substrate is shown; after removing the liner 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 note describes the preparation of a photochromic film based on polymethyl methacrylate (PMMA) with a protective overcoat on a polycarbonate substrate, which is embedded with Cu-doped tungsten trioxide (WO3) nanoparticles.

[0143] A photochromic film comprises the photochromic dispersion material of embodiment 2, and a method for preparing the photochromic 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 on a polycarbonate film substrate using a doctor blade to form a thin film, which 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 dry film thickness of the photochromic film is 40 μm, and the mass of the WO3 nanoparticles is 4% of the dry film mass of the photochromic film. After the photochromic film is cooled and placed at room temperature to dry naturally for 1 day, the adhesion of the film to the PC substrate is good, which is verified by a cross-hatch tape test according to the 4B classification of the ASTM D3359 standard.

[0146] Figure 4 The colored state and transparent state of the photochromic film prepared in Application Example 2 without being covered with PDMS topcoat and with being covered with PDMS topcoat are shown;

[0147] in,

[0148] Figure 4 (a) shows the comparison between the colored state and the transparent state of the photochromic film prepared in Application Example 2 without being covered with PDMS topcoat and with being covered with 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 can be seen that the silicone protective layer was prepared by mixing the silicone components in a ratio of 1:10 using the Silgard 184 silicone elastomer kit. The photochromic dispersion material was then coated on the protective layer using a 14 μm wire rod and cured at 80°C for 2 hours. The discoloration and fading characteristics of the coating were not affected by the PDMS protective layer.

[0151] Application Example 3

[0152] This application note describes the preparation of an adhesive photochromic film with a scratch-resistant protective layer based on polymethyl methacrylate (PMMA) photochromic film embedded with copper-doped tungsten trioxide (WO3) nanoparticles using a one-step mixing method and coated on top with a scratch-resistant hard coating with UV-absorbing properties.

[0153] A photochromic film comprises the photochromic dispersion material of embodiment 3, and a method for preparing the photochromic film comprises the following steps:

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

[0155] The dry film thickness of the photochromic film is 40 μm. A layer of acrylic adhesive is pasted on the surface of the photochromic film so as to peel it off from the substrate, thereby obtaining an adhesive smart window film.

[0156] The UV-curable aliphatic urethane acrylate Ebecryl 225 was mixed with ethyl acetate (Ebecryl 225: ethyl acetate = 2:1, m / m), and then 7 wt% of Omnirad TPO photoinitiator was added, and 1.5 wt% of UV absorber Tinuvin 328 was added to obtain an outer coating. The outer coating was applied on 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 the coating was applied with an intensity of 60 W / cm 2 UV curing for 10s.

[0157] After 20min, 1mW / cm 2 After irradiation with ultraviolet light, the photochromic film with a partial ultraviolet blocking protective layer was obtained, and its visible light transmittance was only reduced by 5%, compared with a 26% reduction for the photochromic film without a protective layer. 2 Under ultraviolet light, the visible light transmittance of both dropped to 40%, indicating that the color change threshold had changed due to the presence of the protective layer.

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

[0159] The photochromic film with scratch-resistant hard coating passed the ASTM D1044 friction test using Rotating platform friction tester. Its haze increased by 4%, while the photochromic film without anti-scratch protection layer had a haze increase of 31%.

[0160] Application Example 4

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

[0162] A photochromic film comprises the photochromic dispersion material of embodiment 4, and a method for preparing the photochromic film comprises the following steps:

[0163] On a slot coater with a width of 40 cm, the photochromic dispersion material of Example 4 was coated on a PET substrate at a coating speed of 3 m / min to form a thin film, which was then placed in a drying zone of a hot air oven with a length of 10 m and a temperature of 100° C. and dried for 200 s to obtain the photochromic film.

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

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

[0166] Application Example 5

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

[0168] A photochromic film comprises the photochromic dispersion material of embodiment 5, and a method for preparing 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 on a 4 mm float glass plate by blade coating to form a thin film, and then placed on a 90° C. hot plate with a 90° C. hot air gun on top and dried for 10 min to obtain the photochromic film.

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

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

[0172] The photochromic film has strong adhesion to the glass plate, and the adhesion test according to ASTM D3359 meets Class 2B. Under simulated sunlight, the visible light transmittance T of the photochromic film is vis Reduced from 90% to 75%.

[0173] Application Example 6

[0174] This application note describes the preparation of polymethyl methacrylate (PMMA) based photochromic thin films coated on PMMA substrates with embedded copper doped tungsten trioxide (WO3) nanoparticles and the addition of additional pigments and light stabilizers on the PMMA substrate.

[0175] A photochromic film, comprising the photochromic dispersion material of embodiment 6, wherein the preparation method of the photochromic 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 on a 2 mm thick PMMA plate using a doctor blade to form a thin film, which 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 dry film thickness of the photochromic film is 40 μm, and the mass of WO3 nanoparticles is 5% of the dry film mass of the photochromic film. After cooling and further drying under ambient conditions for 1 day, the photochromic film has good adhesion to the PC substrate and passes the 2B type adhesion test of ASTM D3359.

[0178] Figure 8 The transmission spectrum of the photochromic 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 Application Example 6 under the full solar spectrum is reduced by 15%. After simulated sunlight exposure, the transmittance changes to 31%. Compared with the photochromic film without carbon black and light stabilizer, its transmittance changes to 42%.

[0180] Application Example 7

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

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

[0183] in,

[0184] Fig. 9 (a) shows that in Application Example 7, no dopant is added, and in the colored state, the film has the same coloring speed and the same transmittance;

[0185] Fig. 9 (b) shows that in Application Example 7, the fading speed of the film is much lower than that of the film with dopant added;

[0186] Depend on Fig. 9 It can be seen that the intensity is 100mW / m 2 After irradiation with 365nm LED light for 15s, the visible light transmittance T of the photochromic film prepared in Example 7 is vis , from 89% in the transparent state to 50% in the colored state; the solar transmittance T sol , from 88% in the transparent state to 55% in the colored state. After removing the UV lamp for 2 hours, the speed at which the photochromic film recovers from the colored state to the transparent state is much lower than that of the film with dopants added.

[0187] Application Example 8

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

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

[0190] in,

[0191] Fig.10 (a) shows that the photochromic film prepared in Application Example 8 is colored under ultraviolet irradiation;

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

[0193] Depend on Fig.10 It can be seen that the intensity is 100mW / m 2 After irradiation with ultraviolet light for 60 seconds, the visible light transmittance T of the photochromic film prepared in Example 8 is vis , from 86% in the transparent state to 60% in the colored state; the solar transmittance T sol , from 85% in the transparent state to 65% in the colored state. After the UV lamp is removed, the photochromic film recovers from the colored state to the transparent 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 present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0195] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes 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 a photochromic nanoparticle precursor and dispersed during and after mixing in a solvent; The photochromic nanoparticles are formed in two non-orthogonal solvents or in a single solvent.

2. The photochromic dispersion material according to claim 1, characterized in that: The photochromic dispersion material further includes a dopant, and the dopant is a transition metal.

3. The photochromic dispersion material according to claim 2, characterized in that: The transition metal is selected from one or more of ferric chloride, iodine, cuprous chloride, cupric chloride or lithium chloride.

4. The photochromic dispersion material according to claim 1, characterized in that: The photochromic dispersion material further comprises an additive, wherein the additive is selected from one or more of a wetting agent, a stabilizer or a dye.

5. The photochromic dispersion material according to claim 1, characterized in that: The photochromic nanoparticles are wide bandgap semiconductor materials, and the wide bandgap semiconductor materials are selected from one or more of titanium dioxide, tungsten trioxide or molybdenum trioxide.

6. The photochromic dispersion material according to claim 1, characterized in that: The polymer is selected from one or more of polymethyl methacrylate and polyacrylic acid.

7. The photochromic dispersion material according to claim 1, characterized in that: The solvent is selected from one or more of ethylene glycol, diethylene glycol, acetophenone, ethyl lactate, anisole or cyclohexanone.

8. The method for preparing the photochromic dispersion material according to any one of claims 1 to 7, characterized in that: The steps include: S1, adding the polymer to the solvent, heating and stirring, to obtain solution 1; S2, adding a photochromic nanoparticle precursor and a dopant into a solvent, stirring at room temperature or under heating conditions, to obtain a solution 2; S3, blending the solution 1 and the solution 2, then adding additives, and stirring evenly to obtain a photochromic dispersion material; or The photochromic nanoparticle precursor, polymer and dopant are added into the solvent, heated and stirred, and after cooling, additives are added and stirred evenly to obtain the photochromic dispersed material.

9. A photochromic film, characterized in that: The photochromic film comprises the photochromic dispersion material according to any one of claims 1 to 7, and the preparation method of the photochromic film comprises the following steps: The photochromic dispersion material is coated on a substrate, heated and dried to obtain a photochromic film.

10. Application of the photochromic film of claim 9 as an adaptive dimming smart window film in adaptive sunlight and solar heat management.

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