Electrochromic film, method for manufacturing the same, and electrolyte composition used therefor

Abstract

An electrochromic film according to one embodiment includes a base layer, a conductive layer, a color changing layer, and an electrolyte layer, in which the electrolyte layer includes repeating units having a specific structure, thereby exhibiting a significantly faster transmittance change rate than a conventional electrochromic film, and has excellent heat resistance and durability even in a high-temperature and high-humidity severe environment higher than a specific temperature and / or higher than a specific humidity, thereby improving the discoloration rate and performance. Therefore, the electrochromic film can be used for electrochromic devices and can also be used as an intelligent window to be applied to various fields such as electronic equipment, automobiles and buildings.

Description

Technical Field

[0001] The present invention relates to an electrochromic film with excellent heat resistance and durability, a method for preparing the electrochromic film, and an electrolyte composition for the electrochromic film. Background Technology

[0002] Recently, with increasing public awareness of environmental protection, there is also a growing focus on improving energy efficiency. As an example, research and development of technologies such as smart windows and energy harvesting are actively underway. Smart windows, in particular, refer to an active control technology that can improve energy efficiency and provide a comfortable environment for users by adjusting the degree of light transmission from the outside. This is a fundamental technology that can be widely applied in various industrial fields. Smart windows utilize electrochromism as their basic principle. Electrochromism is a phenomenon where an electrochemical oxidation or reduction reaction occurs when an applied power source is applied, thereby changing the optical properties of electrochromic active materials, such as their inherent color or light transmittance.

[0003] Typically, the electrochromic film used in such electrochromic devices comprises a substrate layer, a conductive layer, a color-changing layer, and an electrolyte layer. Here, the electrolyte layer serves as the lithium-ion transport pathway, thus significantly contributing to the performance and durability of the electrochromic film. The electrolyte layer is formed by coating an electrolyte composition containing a polymer resin and a lithium salt onto a chromium layer and then curing it by heating or ultraviolet light.

[0004] However, when the electrolyte layer is heated, its skeletal structure may shrink or undergo slight thermal curing, which reduces the space available for lithium ion transport, thus slowing down the discoloration process. This shrinkage can be exacerbated, especially when exposed to harsh environments with high temperature and humidity, further hindering lithium ion transport, reducing heat resistance and durability, and consequently leading to problems such as decreased discoloration performance.

[0005] [Existing Technical Documents]

[0006] (Patent Document 1) Korean Patent No. 1862200 (May 23, 2018). Summary of the Invention

[0007] Technical issues

[0008] The present invention aims to solve the problems existing in the prior art.

[0009] One object of the present invention is to provide an electrochromic film that can prevent the electrolyte layer from over-curing and can stably maintain the skeletal structure of the electrolyte layer even in harsh environments with high temperature and high humidity, thereby enabling smooth lithium ion transport and having excellent heat resistance and durability, thereby improving the color change speed and performance; and a method for preparing the electrochromic film.

[0010] One object of the present invention is to provide an electrolyte composition for the above-mentioned electrochromic film.

[0011] Solution to the problem

[0012] To achieve the above objectives, one embodiment provides an electrochromic film comprising a substrate layer, a conductive layer, a color-changing layer, and an electrolyte layer, wherein the electrolyte layer comprises repeating units of Formula 1:

[0013] Formula 1

[0014]

[0015] In Equation 1, m ranges from 1 to 20.

[0016] Another embodiment provides a method for preparing an electrochromic film, the method comprising forming a substrate layer, a conductive layer on the substrate layer, a color-changing layer on the conductive layer, and an electrolyte layer on the color-changing layer, wherein the electrolyte layer is formed using an electrolyte composition comprising a polymer resin, a lithium salt compound, and a curing modifier, and the curing modifier comprises repeating units of Formula 1 above.

[0017] Another embodiment provides an electrolyte composition comprising a polymer resin, a lithium salt compound, and a curing modifier, wherein the curing modifier comprises repeating units of Formula 1 above.

[0018] Beneficial effects of the invention

[0019] According to one embodiment, the electrolyte layer contained in the electrochromic film comprises repeating units with a specific structure, thus exhibiting a significantly faster rate of transmittance change compared to conventional electrochromic films. Even in harsh environments with high temperature and / or high humidity exceeding specific limits, it retains excellent heat resistance and durability, thereby enhancing color development performance.

[0020] Therefore, electrochromic films can be used as smart windows in various fields such as electronic devices, automobiles, and buildings. Attached Figure Description

[0021] Figure 1 A cross-section of an electrochromic film according to one embodiment is schematically shown.

[0022] Figure 2 A cross-section of an electrochromic film according to another embodiment is schematically shown.

[0023] Figure 3 A cross-section of an electrochromic film according to another embodiment is schematically shown.

[0024] Figure 4 A cross-section of an electrochromic film according to another embodiment is schematically shown.

[0025] Figure 5 A cross-section of an electrochromic film according to another embodiment is schematically shown.

[0026] Figure 6 A method for preparing an electrochromic film according to one embodiment is illustrated schematically.

[0027] Figure 7 A method for measuring the transmittance of an electrochromic film according to one embodiment is shown.

[0028] Figure 8 The points showing the measurements of the transmittance of the electrochromic film according to one embodiment are displayed.

[0029] Figure 9a It is a perspective view that conceptually shows a window on which an electrochromic film according to one implementation scheme is applied.

[0030] Figure 9b It is along Figure 9a A cross-sectional view taken along line A-A', and its magnified view.

[0031] <Explanation of Figure Markers>

[0032] 10: Window; 100: Electrochromic film; 110: Base layer (first base layer); 111: First A primer layer; 112: First B primer layer; 120: First barrier layer; 121: First A barrier layer; 122: First B barrier layer; 123: First C barrier layer; 130: Transmittable structure; 131: Conductive layer (first conductive layer); 133: Color-changing layer (first color-changing layer); 135: Electrolyte layer; 137: Second color-changing layer; 139: Second conductive layer 140: Second barrier layer, 141: Second A barrier layer, 142: Second B barrier layer, 143: Second C barrier layer, 150: Second base layer, 151: Second A primer layer, 152: Second B primer layer, 160: Release film layer, 161: Adhesive layer, 170: Hard coating layer, 210: Light source, 220: Measuring device, A-A': Cutting line, L1: Length of electrochromic film, P1: Center point of electrochromic film, P2 to P5: Edge points of electrochromic film. Detailed Implementation

[0033] Best Implementation of the Invention

[0034] Various embodiments and examples of the present invention will now be described in detail with reference to the accompanying drawings.

[0035] In this specification, detailed descriptions of known structures or functions will be omitted if it is determined that such detailed descriptions would obscure the subject matter of the invention. Furthermore, for ease of description, the dimensions of various elements in the drawings may be exaggerated or omitted, and they may differ from the actual dimensions.

[0036] In this specification, whenever an element is referred to as being formed, connected, or combined on or under another element, it means all cases in which an element is formed, connected, or combined with another element, directly or indirectly. Furthermore, it should be understood that the terminology of "on" and "under" may vary depending on the orientation of the object being observed, for each component.

[0037] In this specification, the terms used to refer to the various components are for the purpose of distinguishing them from each other and are not intended to limit the scope of the invention. Furthermore, in this specification, unless the context otherwise requires, singular expressions should be interpreted to include plural forms.

[0038] In this specification, the word "comprising" is intended to specify a particular feature, area, step, process, element, and / or component. Unless otherwise expressly stated, the presence or addition of any other feature, area, step, method, element, and / or component is not excluded.

[0039] Throughout this specification, the terms "first," "second," etc., are used to describe various components. However, these components should not be limited by these terms. These terms are used to distinguish one component from another.

[0040] Unless otherwise stated, all numbers and expressions relating to the quantities of components, reaction conditions, etc., used herein should be understood to be modified by the term “about”.

[0041] Electrochromic film

[0042] In one embodiment, an electrochromic film is provided, comprising a substrate layer, a conductive layer, a color-changing layer, and an electrolyte layer, wherein the electrolyte layer comprises repeating units of Formula 1:

[0043] Formula 1

[0044]

[0045] In Equation 1, m ranges from 1 to 20.

[0046] In the repeating unit of Equation 1 above, apart from the bond connecting two naphthol rings, the bond in each naphthol ring that represents the connection to the next repeating unit can be understood as being connected to any carbon atom that constitutes each naphthol ring.

[0047] According to one embodiment, the electrolyte layer contained in the electrochromic film comprises repeating units with a specific structure, thus exhibiting a significantly faster rate of transmittance change compared to conventional electrochromic films. Even in harsh environments with high temperature and / or high humidity exceeding specific limits, it retains excellent heat resistance and durability, thereby enhancing color development performance.

[0048] The layer structure, properties, effects, and applications of electrochromic films will be described in more detail below.

[0049] Layer structure of electrochromic film

[0050] Electrochromic films consist of a base layer, a conductive layer, a color-changing layer, and an electrolyte layer.

[0051] Specifically, the electrochromic film includes a substrate layer and a light-transmitting variable structure on the substrate layer, which is capable of adjusting coloring and fading in response to an applied voltage. The light-transmitting variable structure may include a conductive layer, a color-changing layer, and an electrolyte layer.

[0052] Figures 1 to 5 Each schematically shows a cross-section of the electrochromic film according to its respective embodiment.

[0053] like Figure 1 As shown, an electrochromic film (100) according to one embodiment may sequentially include a substrate layer (110) and a light-transmitting variable structure (130), the light-transmitting variable structure including a conductive layer (131), a color-changing layer (133) and an electrolyte layer (135).

[0054] Furthermore, the electrochromic film may include one, two, or more substrate layers, one, two, or more conductive layers, and one, two, or more color-changing layers. For example, the electrochromic film may include a pair of substrate layers, a pair of conductive layers, and a pair of color-changing layers.

[0055] Furthermore, electrochromic films can have various structures that are altered or added based on the substrate layer, conductive layer, color-changing layer, and electrolyte layer.

[0056] like Figure 2As shown, according to another embodiment, the electrochromic film (100) may further include a first barrier layer (120) located between a first substrate layer (110) and a light transmission variable structure (130), the light transmission variable structure (130) including a conductive layer (131), a color-changing layer (133) and an electrolyte layer (135); and may further include a second barrier layer (140) located between a second substrate layer (150) and the light transmission variable structure (130).

[0057] like Figure 3 As shown, the electrochromic film (100) according to another embodiment includes a first base layer (110), a first barrier layer (120), a light-transmitting variable structure (130), a second barrier layer (140), and a second base layer (150) in sequence, wherein the light-transmitting variable structure (130) may include a first conductive layer (131), a first color-changing layer (133), an electrolyte layer (135), a second color-changing layer (137), and a second conductive layer (139) in sequence.

[0058] When a voltage is applied to the first conductive layer (131) and the second conductive layer (139), the overall transmittance may increase or decrease as specific ions or electrons are transported from the second photochromic layer (137) to the first photochromic layer (133) through the electrolyte layer (135). For example, when the transmittance of the second photochromic layer (137) decreases, the transmittance of the first photochromic layer (133) may also decrease. Furthermore, when the transmittance of the second photochromic layer (137) increases, the transmittance of the first photochromic layer (133) may also increase.

[0059] like Figure 4 As shown, according to another embodiment, the electrochromic film (100) sequentially includes a first substrate layer (110), a first barrier layer (120), a light-transmitting variable structure (130), a second barrier layer (140), and a second substrate layer (150), wherein the first barrier layer (120) may sequentially include a first A barrier layer (121) and a first B barrier layer (122); or may sequentially include a first A barrier layer (121), a first B barrier layer (122), and a first C barrier layer (123).

[0060] Specifically, a first A barrier layer (121) and a first B barrier layer (122) may be sequentially laminated on the first base layer (110), or a first A barrier layer (121), a first B barrier layer (122), and a first C barrier layer (123) may be sequentially laminated on the first base layer (110).

[0061] Furthermore, the second barrier layer (140) may include a second A barrier layer (141) and a second B barrier layer (142), or may include a second A barrier layer (141), a second B barrier layer (142), and a second C barrier layer (143). Specifically, the second A barrier layer (141) and the second B barrier layer (142) may be sequentially laminated under the second substrate layer (150), or the second A barrier layer (141), the second B barrier layer (142), and the second C barrier layer (143) may be sequentially laminated.

[0062] like Figure 5 As shown, the electrochromic film (100) according to another embodiment may further include a release film layer (160) located on the side of the first base layer (110) opposite to the side laminated with the first barrier layer (120). An adhesive layer (161) may be formed on one side of the release film layer. In addition, primer layers (111, 112, 151, 152) may be laminated on one or both sides of the first base layer (110) or the second base layer (150). Furthermore, the electrochromic film (100) may also include a hard coating layer (170) located on the side of the second base layer (150) opposite to the side laminated with the second barrier layer (140).

[0063] The thickness of the electrochromic film (100) can be from 100 μm to 1,000 μm. Specifically, the thickness of the electrochromic film (100) can be 100 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, or 400 μm or more, and can be 1,000 μm or less, 900 μm or less, 800 μm or less, 700 μm or less, or 600 μm or less. Specifically, the thickness of the electrochromic film (100) can be from 100 μm to 1,000 μm, 100 μm to 800 μm, 100 μm to 700 μm, 200 μm to 700 μm, 200 μm to 600 μm, 300 μm to 800 μm, 300 μm to 700 μm, or 400 μm to 600 μm, but is not limited thereto.

[0064] The electrochromic film (100) may have 4 or more layers, 5 or more layers, 6 or more layers, or 7 or more layers.

[0065] The characteristics of each layer of the electrochromic film, such as composition and properties, can be combined with each other.

[0066] The following will describe each constituent layer in detail.

[0067] Electrolyte layer

[0068] An electrochromic film according to one embodiment of the present invention includes an electrolyte layer.

[0069] The electrolyte layer may serve as a lithium-ion transport pathway and may have a significant impact on durability and color-changing properties, such as the rate of color change.

[0070] Specifically, refer to Figure 3 The electrolyte layer (135) may be located between the first color-changing layer (133) and the second color-changing layer (137). The electrolyte layer can be formed by coating an electrolyte composition comprising a polymer resin, a lithium salt compound and a curing modifier onto one side of the color-changing layer, for example, one of the first color-changing layer (133) and the second color-changing layer (137), and then curing it by heating or ultraviolet light.

[0071] The electrolyte layer comprises repeating units of Equation 1 below:

[0072] Formula 1

[0073]

[0074] In Equation 1, m ranges from 1 to 20.

[0075] According to one embodiment, the electrolyte layer comprises at least one repeating unit of Formula 1 above, having a bulky aromatic compound structure, specifically 1,1'-bi-2-naphthol, linked to a methylene (CH2) group. Therefore, for the smooth transport of lithium ions, sufficient space is formed between the two naphthol-linked structures in the repeating unit, while the repeating unit of Formula 1 acts as a support for the electrolyte layer, thereby stably maintaining the skeletal structure of the electrolyte layer and making the electrolyte layer more robustly formed.

[0076] Furthermore, the electrolyte layer can further improve the performance of the electrochromic film; in particular, compared with the electrolyte layer composed of repeating units of aliphatic compound structures, it can further improve durability and heat resistance. Therefore, it has a significant advantage in maintaining excellent color-changing performance, for example, exhibiting a rapid rate of change in transmittance even in harsh environments with high temperature and high humidity.

[0077] In Equation I, m can be 1 to 20, 2 to 20, 3 to 20, 5 to 20, 5 to 18, 5 to 16, or 5 to 15.

[0078] When m in Equation 1 meets the above range, the desired electrolyte layer can be easily achieved, thereby enhancing the color-changing performance.

[0079] According to one implementation, the electrolyte layer may consist only of repeating units from Equation 1 above. In this case, the electrolyte layer can be strengthened while ensuring the lithium-ion transport path, thereby maintaining excellent electrochromic properties even after exposure to harsh environments with high temperature and humidity.

[0080] Furthermore, according to one embodiment, the repeating unit of Formula 1 above can be combined with other compounds.

[0081] For example, the methylene (CH2) attached to the repeating unit of Formula 1 above can be combined with an aromatic compound containing an alkyl group of 5 to 20 carbon atoms to form an aromatic compound. Furthermore, the aromatic compound can also be substituted with a hydroxyl group (-OH).

[0082] According to one embodiment, the electrolyte layer may further include repeating units of Formula 2, as well as repeating units of Formula 1 above:

[0083]

Formula 2

[0084]

[0085] In Formula 2, A is an aromatic group, n is 1 to 30, and x is 1 or 2.

[0086] Since the electrolyte layer according to one embodiment may further include repeating units of Formula 2, it can additionally impart flexibility to the electrolyte layer firmly formed by the repeating units of Formula 1. In this case, even in harsh environments with high temperature and high humidity above a certain temperature and / or above a certain humidity, a faster rate of change of transmittance can be achieved, and heat resistance and durability can be further improved, thereby further improving the color-changing performance.

[0087] In Formula 2, A may include an aromatic group having 5 to 20 carbon atoms, an aromatic group having 5 to 12 carbon atoms, an aromatic group having 5 to 10 carbon atoms, or an aromatic group having 5 to 8 carbon atoms.

[0088] In Equation 2, n can be 1 to 30, 2 to 30, 5 to 30, 6 to 30, 8 to 30, or 10 to 30.

[0089] In Equation 2, x can be 1 or 2, for example, x can be 1.

[0090] Specifically, Equation 2 may include repeated units from Equation 2-1:

[0091] Equation 2-1

[0092]

[0093] According to one embodiment, the electrolyte layer may contain repeating units of the following formula 3:

[0094]

Formula 3

[0095]

[0096] In Equation 3, m and n are as described above.

[0097] When the electrolyte layer contains repeating units of Formula 3, the large volume structure of the repeating units of Formula 1 allows for the formation of a robust electrolyte layer and ensures a stable lithium-ion transport path. Simultaneously, the repeating units of Formula 2 are smaller in volume than those of Formula 1, imparting flexibility to the electrolyte layer and facilitating smoother lithium-ion transport. Therefore, heat resistance, durability, and color-changing properties can be further improved.

[0098] Meanwhile, when the electrolyte layer contains repeating units of Formula 3, the ratio of the content of repeating units of Formula 1 to repeating units of Formula 2 may be important.

[0099] The electrolyte layer may contain repeating units of Formula 1 and Formula 2 above in a molar ratio of 100:0 to 100:50. Specifically, the molar ratio of the repeating unit of Formula 1 to the repeating unit of Formula 2 in the electrolyte layer can be 100:0 to 100:40, 100:0 to 100:30, 100:0 to 100:25, 100:10 to 100:50, 100:10 to 100:40, 100:10 to 100:30, 100:15 to 100:50, 100:15 to 100:40, 100:15 to 100:30, 100:20 to 100:50, 100:20 to 100:40, 100:20 to 100:30, 100:25 to 100:50, 100:25 to 100:40, 100:25 to 100:30, or 100:20 to 100:25.

[0100] When the electrolyte layer contains repeating units of Formula 1 and Formula 2 within the above molar ratio range, it may be more conducive to producing the desired effect.

[0101] If the electrolyte layer contains an excessive amount of repeating units of Equation 2 above, or only contains repeating units of Equation 2 above, then due to the lack of large-volume repeating units of Equation 1 above, it is difficult to form a space within the electrolyte layer that is conducive to lithium-ion transport, and it may be difficult to support the framework structure of the electrolyte layer, thus making it difficult to produce the expected effect. Especially in high temperature and high humidity environments, heat resistance and durability will decrease, thereby significantly reducing transmission performance.

[0102] Furthermore, the electrolyte layer may include a polymer resin. Specifically, the polymer resin may be selected from, but is not limited to, acrylic resin, epoxy resin, silicone resin, polyimide resin, or polyurethane resin. In this case, the acrylic resin may be a thermosetting acrylic resin or a photocurable acrylic resin, etc. The polyurethane resin may be a thermosetting polyurethane resin, a photocurable polyurethane resin, or a waterborne polyurethane resin, etc.

[0103] In addition, the electrolyte layer may include lithium salt compounds.

[0104] The lithium salt compound may be selected from, but is not limited to, the group consisting of LiClO4, LiBF4, LiAsF6, LiPF6, LIBOB (lithium bis(oxalate)borate), LiDODFP (lithium difluorobis(oxalate)phosphate), and LITFSI (lithium bis(trifluoromethane)sulfonylimide).

[0105] The specific content and properties of each component contained in the electrolyte layer will be described in more detail in the electrolyte composition described below.

[0106] The electrolyte layer can be formed by coating a liquid or gel-like electrolyte composition onto the color-changing layer, specifically onto either the first or second color-changing layer. Specifically, the electrolyte layer can be formed by wet coating one side of either the first or second color-changing layer, followed by drying. Using a wet coating method for the electrolyte layer increases the coating thickness or makes it easier to control, which is advantageous for improving ionic conductivity or color-changing speed. On the other hand, if the electrolyte layer is coated using sputtering instead of a wet coating method, there is a risk that the coating may crack due to the formation of a thin film, or even if no damage occurs, the ionic conductivity may decrease.

[0107] The ionic conductivity of the electrolyte layer can be 10. -3 mS / cm or higher. Specifically, the ionic conductivity of the electrolyte layer can be 10-1. -3 mS / cm to 10 3 mS / cm, or 10 -3 mS / cm to 10 2 The value is mS / cm, but not limited to this. If the ionic conductivity of the electrolyte layer is within the above range, the desired variable light transmittance can be achieved, and it offers advantages in flexibility and reliability under high temperature and high humidity conditions.

[0108] The adhesive strength of the electrolyte layer can be 200 g / in or higher. Specifically, the adhesive strength of the electrolyte layer can be from 200 g / in to 900 g / in or from 200 g / in to 700 g / in, but is not limited to these. If the adhesive strength of the electrolyte layer is within the above range, it can adhere well to both substrates, thus successfully exhibiting the performance of the electrochromic film and the electrochromic device.

[0109] The thickness of the electrolyte layer can be 30 µm to 200 µm, 50 µm to 200 µm, 50 µm to 150 µm, 70 µm to 130 µm, 80 µm to 120 µm or 100 µm to 120 µm.

[0110] When the electrolyte layer thickness meets the above-mentioned range, it may be more conducive to achieving the desired effect. Specifically, the electrochromic film has heat resistance and durability, and at the same time, it ensures that the ion transport path between the first and second color-changing layers is within an appropriate length, thereby achieving light transmission change performance at an appropriate speed.

[0111] If the electrolyte layer thickness exceeds the above range, discoloration may take a long time, which could hinder the achievement of the desired effect. If the electrolyte layer thickness is less than the above range, the desired effect may be negligible.

[0112] Color-changing layer

[0113] An electrochromic film according to one embodiment of the present invention includes a color-changing layer.

[0114] A color-changing layer is a layer whose light transmittance changes; it can be a layer that causes changes in the light transmittance of an electrochromic film.

[0115] The color-changing layer may include a first color-changing layer and a second color-changing layer.

[0116] The first and second color-changing layers can each contain electrochromic materials with complementary color-changing properties. Complementary color-changing properties refer to the fact that the color-changing reaction types of the electrochromic materials are different from each other.

[0117] For example, if an oxidizing color-changing material is used in the first color-changing layer, a reducing color-changing material can be used in the second color-changing layer. Similarly, if a reducing color-changing material is used in the first color-changing layer, an oxidizing color-changing material can be used in the second color-changing layer.

[0118] Specifically, the first color-changing layer may include a reductive color-changing material, and the second color-changing layer may include an oxidizing color-changing material.

[0119] Oxidative color-changing materials are materials that change color when an oxidation reaction occurs, while reductive color-changing materials are materials that change color when a reduction reaction occurs.

[0120] In other words, in a color-changing layer coated with an oxidizing color-changing material, if an oxidation reaction occurs, a coloring reaction will occur; if a reduction reaction occurs, a fading reaction will occur. Furthermore, in a color-changing layer coated with a reducing color-changing material, if a reduction reaction occurs, a coloring reaction will occur; if an oxidation reaction occurs, a fading reaction will occur.

[0121] As a specific example, the reductive color-changing material may be one or more of the following groups: titanium dioxide (TiO), vanadium dioxide (V2O5), niobium pentoxide (Nb2O5), chromium dioxide (Cr2O3), manganese dioxide (MnO2), iron dioxide (FeO2), cobalt dioxide (CoO2), nickel dioxide (NiO2), rhodium dioxide (RhO2), tantalum dioxide (Ta2O5), iridium dioxide (IrO2), tungsten dioxide (WO2, WO3, W2O3 and W2O5), viologen, and combinations thereof, but is not limited thereto.

[0122] As a specific example, oxidative color-changing materials can be one or more, but are not limited to, selected from the group consisting of nickel oxide (e.g., NiO and NiO2), manganese oxide (e.g., MnO2), cobalt oxide (e.g., CoO2), iridium magnesium oxide, nickel magnesium oxide, titanium vanadium oxide, Prussian blue pigment, and combinations thereof. Prussian blue pigment is a deep blue pigment, and for example, it can contain a compound with the chemical formula Fe4(Fe(CN)6)3.

[0123] Both the first and second color-changing layers may further comprise a polymer resin. This polymer resin may be a flexible resin and is not limited to a specific type. For example, the polymer resin may be a polyurethane acrylic resin, silicone resin, acrylic resin, ester resin, epoxy resin, phenolic resin, polyurethane resin, polyimide resin, or ethylene vinyl acetate resin, but is not limited thereto.

[0124] Furthermore, the number-average molecular weight of the polymer resin may be from 50 g / mol to 10,000 g / mol. Specifically, the number-average molecular weight of the polymer resin may be from 100 g / mol to 10,000 g / mol, 200 g / mol to 10,000 g / mol, or 500 g / mol to 10,000 g / mol, but is not limited thereto.

[0125] The first and second color-changing layers, each based on 100 parts by weight of a reducing or oxidizing color-changing material, may each contain 0.1 to 15 parts, 1 to 15 parts, 2 to 15 parts, 3 to 10 parts, 3 to 7 parts, or 0.1 to 5 parts by weight of a polymer resin. Within the above preferred ranges, the reducing or oxidizing color-changing material can stably adhere to adjacent layers, thereby achieving smooth variable transmittance. Furthermore, it may have an advantage in suppressing visible light transmittance changes that may occur after repeated bending or prolonged power outages.

[0126] At the same time, refer to Figure 3Each of the light-transmitting variable structures (130) includes at least one of a first color-changing layer (133) and a second color-changing layer (137). It may include two or more first color-changing layers or second color-changing layers made of different materials as needed.

[0127] The initial transmittance of the first color-changing layer (133) can be 90% or higher. Within this range, the optical performance of the electrochromic film can be further improved. Meanwhile, the initial transmittance of the second color-changing layer (137) can be 50% or lower. Specifically, an initial transmittance within the above range means that it will appear as a deep blue or light indigo when viewed with the naked eye.

[0128] The thickness of the first color-changing layer (133) can be 100 nm to 1,000 nm, 200 nm to 1,000 nm, 200 nm to 800 nm, 200 nm to 700 nm, 300 nm to 700 nm, or 300 nm to 600 nm. When the thickness of the first color-changing layer is within the above-mentioned preferred range, the change in the transmittance of the variable-transmittance structure may cause a significant change in the transmittance of the entire electrochromic film. It may be more advantageous in suppressing the visible light transmittance changes that may occur after repeated bending or long-term power outages.

[0129] The thickness of the second color-changing layer (137) can be 100 nm to 1,000 nm, 100 nm to 800 nm, 100 nm to 600 nm, 100 nm to 500 nm, 100 nm to 400 nm, 200 nm to 800 nm, or 300 nm to 800 nm, but is not limited thereto. When the thickness of the second color-changing layer (137) is within the above-mentioned preferred range, the film can withstand external impacts well and retain an appropriate amount of ions. At the same time, it is beneficial to make the electrochromic film thinner, ensuring its flexibility and achieving excellent transmittance change characteristics.

[0130] The thickness ratio of the first color-changing layer (133) to the second color-changing layer (137) can be 50:50 to 80:20, 55:45 to 75:25, or 60:40 to 70:30. Within the above preferred thickness ratio range, the color change range from transparent to dark can be wider, and the color change time can be shortened.

[0131] There are no particular limitations on the preparation methods of the first color-changing layer (133) and the second color-changing layer (137), but a wet coating method can be used to form them to a certain thickness or greater. Since the wet coating can form a color-changing layer with a thickness of 100 nm or more, it has advantages in achieving excellent variable transmittance and flexibility. Specifically, the first color-changing layer (133) can be formed by coating a raw material onto one side of the first conductive layer (131) by a wet coating method and then drying. In addition, the second color-changing layer (137) can be formed by coating a raw material onto one side of the second conductive layer (139) by a wet coating method and then drying. The solvent used in the wet coating can be a non-aromatic solvent or an aromatic solvent, specifically, it can be ethanol, acetone and toluene, etc., but is not limited to these.

[0132] conductive layer

[0133] An electrochromic film according to one embodiment of the present invention includes a conductive layer.

[0134] The conductive layer is an electrode layer, which may include a first conductive layer and a second conductive layer.

[0135] Both the first conductive layer and the second conductive layer can include a transparent electrode or a reflective electrode. In one embodiment, one of the first conductive layer and the second conductive layer can be a transparent electrode, and the other can be a reflective electrode. In another embodiment, both the first conductive layer and the second conductive layer can be transparent electrodes.

[0136] refer to Figure 3 The first conductive layer (131) can be formed on the first substrate layer (110) or the first barrier layer (120) by sputter deposition. In addition, the second conductive layer (139) can be formed on the second substrate layer (150) or the second barrier layer (140) by sputter deposition.

[0137] Transparent electrodes can be made of materials with high light transmittance, low sheet resistance, and good penetration resistance, and can be made into the shape of an electrode plate.

[0138] Transparent electrodes may include, for example, materials selected from the group consisting of indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), and combinations thereof.

[0139] The reflective electrode may include at least one material selected from the group consisting of silver (Ag), aluminum (Al), copper (Cu), molybdenum (Mo), gold (Au), tungsten (W), chromium (Cr), and combinations thereof.

[0140] The thickness of the first conductive layer (131) and the second conductive layer (139) can be 100 nm to 500 nm, 100 nm to 400 nm, 100 nm to 300 nm or 150 nm to 250 nm respectively, but is not limited thereto.

[0141] Both the first and second conductive layers can be transparent electrodes or reflective electrodes, and both are composed of indium tin oxide (ITO).

[0142] Specifically, the first conductive layer and the second conductive layer may each contain indium oxide and tin oxide in a mass ratio of 70:30 to 98:2 or 80:20 to 97:3.

[0143] Furthermore, the surface resistance of the first conductive layer and the second conductive layer can be from 5 Ω / sq to 100 Ω / sq, 5 Ω / sq to 80 Ω / sq, 5 Ω / sq to 70 Ω / sq, or 5 Ω / sq to 50 Ω / sq, but is not limited thereto.

[0144] basal layer

[0145] An electrochromic film according to one embodiment of the present invention includes a substrate layer.

[0146] The base layer is used to maintain transparency and durability, and may contain polymer resin.

[0147] The base layer may include a first base layer and a second base layer.

[0148] The first and second base layers can each be flexible plastic films.

[0149] Specifically, the first and second base layers may each comprise one or more polymer resins selected from, but not limited to, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), polycyclohexanediol terephthalate (PCT), polyethersulfone (PES), nylon, polymethyl methacrylate (PMMA), and cyclic olefin polymers (COP). More specifically, both the first and second base layers may comprise polyethylene terephthalate (PET).

[0150] When the first substrate layer and the second substrate layer each contain the aforementioned polymer resin, it is possible to obtain an electrochromic film and an electrochromic device that combine durability and flexibility.

[0151] The transmittance of the first and second substrate layers to light with a wavelength of 550 nm can each be 80% or higher. Specifically, the transmittance of the first and second substrate layers to light with a wavelength of 550 nm can each be 85% or higher, or 90% or higher. The haze of the first and second substrate layers can each be less than 2.0%, 1.8% or less, or 1.5% or less. The elongation of the first and second substrate layers can each be 80% or more. Specifically, the elongation of the first and second substrate layers can each be 90% or more, 100% or more, or 120% or more. Transparency can be achieved when the first and second substrate layers each meet the transmittance and haze ranges described above. Flexibility can be obtained when their elongation meets the ranges described above.

[0152] The thicknesses of the first and second substrate layers can each range from 10 µm to 300 µm. Specifically, the thicknesses of the first and second substrate layers can each be 50 µm to 250 µm, 70 µm to 200 µm, 80 µm to 200 µm, 100 µm to 200 µm, 100 µm to 190 µm, 100 µm to 180 µm, 120 µm to 200 µm, or 150 µm to 200 µm, but are not limited thereto. When the thicknesses of the first and second substrate layers are each within the above ranges, the electrochromic film can have a specific level of elongation and tensile strength, thereby providing a thin, lightweight, and flexible electrochromic film. It also has advantages due to its thinness.

[0153] Barrier layer

[0154] An electrochromic film according to one embodiment of the present invention includes a barrier layer.

[0155] The barrier layer prevents impurities, including moisture or gas, from seeping into the light-transmitting variable structure.

[0156] refer to Figure 4 The first barrier layer (120) may be disposed on the first base layer (110), and the second barrier layer (140) may be disposed under the second base layer (150).

[0157] The first barrier layer (120) and the second barrier layer (140) may each comprise two or more layers. Specifically, the first barrier layer (120) and the second barrier layer (140) may each comprise two or three layers. For example, the first barrier layer (120) may comprise two layers, and the second barrier layer (140) may comprise two layers. Alternatively, the first barrier layer (120) may comprise three layers, and the second barrier layer (140) may comprise three layers.

[0158] The first barrier layer (120) may include a first A barrier layer (121) and a first B barrier layer (122), or it may include a first A barrier layer (121), a first B barrier layer (122), and a first C barrier layer (123). Specifically, the first A barrier layer (121) and the first B barrier layer (122) may be laminated sequentially on the first substrate layer (110), or the first A barrier layer (121), the first B barrier layer (122), and the first C barrier layer (123) may be laminated sequentially.

[0159] Furthermore, the second barrier layer (140) may include a second A barrier layer (141) and a second B barrier layer (142), or may include a second A barrier layer (141), a second B barrier layer (142), and a second C barrier layer (143). Specifically, the second A barrier layer (141) and the second B barrier layer (142) may be sequentially laminated under the second substrate layer (150), or the second A barrier layer (141), the second B barrier layer (142), and the second C barrier layer (143) may be sequentially laminated.

[0160] In this case, the thickness of the first A-blocking layer and the second A-blocking layer can be 10 nm to 50 nm, 10 nm to 40 nm, or 10 nm to 30 nm, respectively, but is not limited thereto. In addition, the thickness of the first B-blocking layer and the second B-blocking layer can be 30 nm to 100 nm, 30 nm to 80 nm, 30 nm to 70 nm, or 40 nm to 60 nm, respectively, but is not limited thereto.

[0161] The thickness ratio of the first A-block layer to the first B-block layer can be 1:2 to 1:10, 1:2.5 to 1:10, or 1:2.5 to 1:7.5, and the thickness ratio of the second A-block layer to the second B-block layer can be 1:2 to 1:10, 1:2.5 to 1:10, or 1:2.5 to 1:7.5, but is not limited thereto. Within the above-mentioned preferred thickness ratio range, the optical properties, refractive index, and long-term reliability of the film, such as weather resistance, can be further improved.

[0162] The first barrier layer (120) and the second barrier layer (140) may each comprise at least one selected from the group consisting of metal oxides, metal nitrides, metal oxide nitrides, metal oxide-like compounds, metal nitride-like compounds, and combinations thereof. Specifically, the first A barrier layer may comprise a metal nitride or a metal oxide-like compound, and the first B barrier layer may comprise a metal oxide or a metal oxide-like compound. Furthermore, the second A barrier layer may comprise a metal nitride or a metal nitride-like compound, and the second B barrier layer may comprise a metal oxide or a metal oxide-like compound.

[0163] Specifically, the first A-barrier layer may include silicon nitride (SiNx), and the first B-barrier layer may include silicon oxide (SiOx). Furthermore, the second A-barrier layer may include silicon nitride (SiNx), and the second B-barrier layer may include silicon oxide (SiOx). The Si:N ratio of silicon nitride may be from 1.0:0.8 to 1.0:1.2, and the Si:O ratio of silicon oxide may be from 1.0:1.7 to 1.0:2.3, but is not limited thereto. Within the above preferred composition range, the desired performance can be achieved even using a thin barrier layer, and moisture penetration can be prevented to the maximum extent, thereby further improving durability and long-term stability.

[0164] Furthermore, the moisture permeability of the first A barrier layer, the first B barrier layer, the second A barrier layer, and the second B barrier layer can each be 0.2 g / day·m³. 2 Or even lower, 0.15 g / day·m 2 Or lower, or 0.1 g / day·m 2 Or lower, but not limited to. Within the above-mentioned preferred thickness and moisture permeability range, the optical properties, refractive index, and long-term reliability of the membrane, such as weather resistance, can be further improved.

[0165] In addition, the first C-barrier layer and the second C-barrier layer may each comprise acrylic resin, epoxy resin, silicone resin, polyimide resin or polyurethane resin.

[0166] The first and second barrier layers can be formed on the first and second substrate layers, respectively, by vacuum deposition. Vacuum deposition can be achieved through physical vacuum deposition or chemical vacuum deposition. Physical vacuum deposition includes thermal vacuum deposition, electron beam (E-beam) vacuum deposition, and sputtering deposition.

[0167] As a specific embodiment, the first barrier layer and the second barrier layer can be formed on the first substrate layer and the second substrate layer respectively by sputtering deposition. Sputtering can be direct current (DC) magnetron sputtering or alternating current (AC) magnetron sputtering. Specifically, DC magnetron sputtering can be reactive plasma sputtering.

[0168] The raw materials used in the deposition process can be one or more metals or metalloids, and there are no particular restrictions on their types. For example, it can contain at least one selected from magnesium (Mg), silicon (Si), indium (In), titanium (Ti), bismuth (Bi), germanium (Ge), and aluminum (Al).

[0169] The reaction gases used in the deposition process can include oxygen (O2) or nitrogen (N2). If oxygen is used as the reaction gas, a barrier layer containing metal oxides or metal-like oxides can be formed. If nitrogen is used as the reaction gas, a barrier layer containing metal nitrides or metal-like nitrides can be formed. If oxygen and nitrogen are properly mixed and used as the reaction gases, a barrier layer containing metal nitrides or metal-like nitrides can be formed.

[0170] Release film layer

[0171] review Figure 5 As shown, the release film layer (160) can be formed on the side of the first base layer (110) opposite to the side of the first barrier layer (120) laminated together.

[0172] The release film layer is used to protect the electrochromic film from external moisture or impurities during storage and transportation. When the electrochromic film is subsequently applied to surfaces such as transparent windows, it can be used after removing the release film layer, if necessary. The release film layer is particularly effective in preventing a decrease in the adhesive strength of the bonding layers.

[0173] The release film layer may contain a polyester-based resin, which may include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polycarbonate (PC).

[0174] Specifically, the thickness of the adhesive layer can be 10 μm to 100 μm, 10 μm to 80 μm, 10 μm to 50 μm, or 12 μm to 50 μm, but is not limited to these.

[0175] The peel strength of the adhesive layer can be 50 gf / inch or lower. Specifically, it may be from 3 gf / inch to 50 gf / inch, or from 10 gf / inch to 50 gf / inch, but is not limited to these.

[0176] An adhesive layer (161) can be formed on one side of the release film layer.

[0177] The adhesive layer (161) may comprise acrylic resin, silicone resin, polyurethane resin, epoxy resin, or polyimide resin. Specifically, the adhesive layer may comprise acrylic resin, in which case it is beneficial to improve optical performance and durability.

[0178] The adhesive layer can block 95% or more, 97% or more, 98% or more, or 99% or more of ultraviolet light (based on 400 nm), but is not limited to these values.

[0179] In addition, the initial adhesive strength of the adhesive layer can be from 0.5 N / inch to 8.0 N / inch, 1.0 N / inch to 7.0 N / inch, or 2.0 N / inch to 6.0 N / inch, but is not limited thereto.

[0180] primer layer

[0181] The primer layer can be laminated on one or both sides of the first substrate layer. Specifically, referring to Figure 5, the first A primer layer (111) can be laminated on one side of the first substrate layer (110), and the first B primer layer (112) can be laminated on the other side.

[0182] Furthermore, the primer layer can be laminated on one or both sides (150) of the second substrate layer. Specifically, the second A primer layer (151) can be laminated on one side of the second substrate layer (150), and the second B primer layer (152) can be laminated on the other side.

[0183] In one embodiment, a primer layer may be disposed between a first barrier layer (120) and a first substrate layer (110). Alternatively, the primer layer may be inserted between a second barrier layer (140) and a second substrate layer (150).

[0184] The primer layers (first primer layer A, first primer layer B, second primer layer A and second primer layer B) may each contain acrylic resin, polyurethane resin, silicone resin or polyimide resin.

[0185] The surface tension of the primer layers (first primer layer A, first primer layer B, second primer layer A, and second primer layer B) can be 35 dynes / cm. 2 Or smaller, or 30 dynes / cm 2 Or smaller.

[0186] The adhesive strength of each primer layer (first A primer layer, first B primer layer, second A primer layer and second B primer layer) can be 3.0 gf / inch or higher, or 3.5 gf / inch or higher.

[0187] The primer layer is used to enhance the adhesion between the base layer and the barrier layer, or to increase the refractive index. Furthermore, the materials, surface tension, peel strength, etc., of the individual primer layers may be the same or different.

[0188] Hard coating

[0189] refer to Figure 5 The electrochromic film (100) may also include a hard coating (170) located on the side of the second base layer (150) opposite to the side laminated with the second barrier layer (140).

[0190] The hard coating (170) may contain acrylic resin, silicone resin, polyurethane resin, epoxy resin or polyimide resin.

[0191] The thickness of the hard coating can be 1 μm to 10 μm, 2 μm to 8 μm, 2 μm to 6 μm, or 2 μm to 5 μm, but is not limited to these.

[0192] Hard-coated pencils can have a hardness of 3H or higher, 4H or higher, or 5H or higher, but are not limited to these.

[0193] The hard coating protects the electrochromic film from external impacts and imparts excellent hardness due to its scratch resistance.

[0194] Furthermore, when the hard coating thickness meets the above-mentioned range, an electrochromic film with flexibility and excellent processability can be obtained. If the hard coating thickness exceeds the above-mentioned range, it is difficult to achieve flexibility. If the hard coating thickness is less than the above-mentioned range, it may be susceptible to external impacts.

[0195] Physical properties of electrochromic films

[0196] When the electrochromic film according to one embodiment possesses the above-mentioned characteristics, its transmittance changes significantly faster compared to conventional electrochromic films. Even in harsh environments with high temperature and / or high humidity exceeding a certain level, it maintains excellent heat resistance and durability, thereby enhancing its color rendering performance.

[0197] According to one implementation, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, when measuring the average visible light transmittance in the maximum colored state, the transmittance difference (ΔT60) in the maximum colored state is expressed by the following equation 1-1. dis It can be less than 3.5%.

[0198] Equation 1-1

[0199] ΔT60 dis (%) = |T dis0 – T dis60 │

[0200] In Equation 1-1, T dis0 The initial transmittance (%) of the sample under maximum coloration conditions, measured at room temperature, is T. dis60 The transmittance (%) of the sample under maximum coloration is measured after 7 days of exposure to 60°C and 60% humidity.

[0201] Specifically, the difference (ΔT60) between the transmittance (%) of the electrochromic film in its maximum colored state after 7 days of exposure to 60°C and 60% humidity and the initial transmittance (%) in its maximum colored state measured at room temperature. dis The percentage can be 3.2% or less, 3.0% or less, 2.8% or less, 2.5% or less, 2.0% or less, 1.8% or less, 1.5% or less, 1.2% or less, 1.0% or less, less than 1.0%, 0.9% or less, or 0.8% or less.

[0202] When the transmittance difference of the electrochromic film (ΔT60) dis When the above range is met, it can maintain excellent electrochromic performance even in harsh environments with high temperature and high humidity.

[0203] For example, refer to Figure 7 and 8 The transmittance of the electrochromic film was measured by placing the electrochromic film (100) sample between the light source (210) and the measuring device (220) and measuring the visible light transmittance at the center point (P1) and four edge points (P2, P3, P4 and P5) in the wavelength range of about 30 nm to 60 nm. The average visible light transmittance value from P1 to P5 was measured by excluding 30 mm from each end of the electrochromic film (100) sample.

[0204] Furthermore, for example, the change in transmittance over time in the colored state can be measured while simultaneously applying a voltage of -1.2 V to the sample in its maximum fading state to induce a return to the maximum colored state. Similarly, the change in transmittance over time in the fading state can be measured while simultaneously applying a voltage of 1.2 V to the sample in its maximum colored state to induce a return to the maximum fading state. Moreover, the coloring and fading tests can be repeated as needed.

[0205] In Equation 1-1, T dis0 It can be, for example, 50% to 80%, 50% to 70%, 55% to 68%, 58% to 68%, 59% to 67%, or 60% to 67%.

[0206] In equation 1-1, T dis60 For example, it can be 50% to 80%, 50% to 70%, 55% to 68%, 58% to 68%, 58% to 66%, 59% to 66%, or 60% to 66%.

[0207] When T dis0 and T dis60 Meeting the above-mentioned ranges may be more conducive to achieving the desired effect.

[0208] Furthermore, according to another embodiment, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, when measuring the average visible light transmittance in the maximum fading state, the transmittance difference (ΔT60) in the maximum fading state is expressed by the following formula 1-2. de It can be 1.2% or less:

[0209]

Formula 1-2

[0210] ΔT60 de (%) = |T de0 – T de60 │

[0211] In Equation 1-2, T de0 The initial transmittance (%) of the sample under the maximum fading state, measured at room temperature, is T. de60 The transmittance (%) of the sample under maximum fading condition was measured after 7 days of exposure to 60°C and 60% humidity.

[0212] Specifically, the difference (ΔT60) between the transmittance (%) of the electrochromic film under the maximum fading state measured after 7 days of exposure to 60°C and 60% humidity and the initial transmittance (%) under the maximum fading state measured at room temperature. de () can be 1.0% or less, less than 1.0%, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, or 0.5% or less.

[0213] When the transmittance difference of the electrochromic film (ΔT60) de When the above range is met, it can maintain excellent electrochromic performance even in harsh environments with high temperature and high humidity.

[0214] In Equation 1-2, T de0 It can be, for example, 10% to 30%, 10% to 25%, 10% to 20%, 10% to 15%, 12% to 15%, or 12% to 14%.

[0215] In Equation 1-2, T de60 It can be, for example, 10% to 30%, 10% to 25%, 10% to 20%, 10% to 18%, 12% to 16%, or 12% to 15%.

[0216] When T de0 and T de60 Meeting the above-mentioned ranges may be more conducive to achieving the desired effect.

[0217] According to another embodiment, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, when measuring the average visible light transmittance in the maximum colored state, the transmittance difference (ΔT60) in the maximum colored state, as expressed by the above formula 1-1, is... dis The transmittance can be less than 3.5%; when measuring the average visible light transmittance under the maximum fading state, the transmittance difference (ΔT60) under the maximum fading state is expressed by the above formula 1-2. de It can be 1.2% or less.

[0218] According to another embodiment, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, when measuring the average visible light transmittance in the maximum colored state, the transmittance difference (ΔT80) in the maximum colored state is expressed by the following equation 2-1. dis It can be 6.0% or less:

[0219] Equation 2-1

[0220] ΔT80 dis (%) = |T dis0 – T dis80 │

[0221] In Equation 2-1, T dis0 The initial transmittance (%) of the sample under maximum coloration conditions, measured at room temperature, is T. dis80 The transmittance (%) of the sample under maximum coloration is measured after 7 days of exposure to 80°C.

[0222] Specifically, the difference (ΔT80) between the transmittance (%) of the electrochromic film under the maximum colored state measured after 7 days of exposure to 80°C and the initial transmittance (%) under the maximum colored state measured at room temperature is considered. dis The percentage can be 5.0% or less, 4.0% or less, 3.0% or less, 2.8% or less, 2.5% or less, 2.0% or less, 1.8% or less, 1.5% or less, 1.4% or less, or 1.2% or less.

[0223] When the transmittance difference of the electrochromic film (ΔT80) dis When the above range is met, it can maintain excellent electrochromic performance even in harsh environments with high temperatures of 80°C or higher.

[0224] In formula 2-1, T dis0 As stated above.

[0225] In Equation 2-1, T dis80It can be, for example, 50% to 80%, 50% to 70%, 55% to 68%, 57% to 68%, or 58% to 66%.

[0226] When T dis80 Meeting the above criteria may be more conducive to achieving the desired results.

[0227] According to another embodiment, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, when measuring the average visible light transmittance under the maximum fading state, the transmittance difference (ΔT80) under the maximum fading state is expressed by the following equation 2-2. de It can be 2.0% or less:

[0228]

Formula 2-2

[0229] ΔT80 de (%) = |T de0 – T de80 │

[0230] In Equation 2-2, T de0 The initial transmittance (%) of the sample under the maximum fading state, measured at room temperature, is T. de80 The transmittance (%) of the sample under maximum fading condition was measured after 7 days of exposure to 80°C.

[0231] Specifically, the difference (ΔT80) between the transmittance (%) of the electrochromic film under the maximum fading state measured after 7 days of exposure to 80°C and the initial transmittance (%) under the maximum fading state measured at room temperature is considered. de The percentage can be 2.0% or less, 1.9% or less, 1.8% or less, 1.7% or less, 1.6% or less, 1.5% or less, 1.4% or less, 1.3% or less, 1.2% or less, 1.1% or less, or 1.0% or less.

[0232] When the transmittance difference of the electrochromic film (ΔT80) de When the above range is met, it can maintain excellent electrochromic performance even in harsh environments with high temperatures of 80°C or higher.

[0233] In formula 2-2, T de0 As stated above.

[0234] In equation 2-2, T de80 It can be, for example, 10% to 30%, 10% to 25%, 10% to 20%, 10% to 18%, 12% to 18%, 12% to 16%, or 12% to 15%.

[0235] When T de80Meeting the above criteria may be more conducive to achieving the desired results.

[0236] According to another embodiment, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, when measuring the average visible light transmittance in the maximum colored state, the transmittance difference (ΔT80) in the maximum colored state, as expressed by the above formula 2-1, is... dis It can be 6.0% or less; when measuring the average visible light transmittance under the maximum fading state, the transmittance difference (ΔT80) under the maximum fading state is expressed by the above formula 2-2. de It can be 2.0% or less.

[0237] According to another embodiment, for an electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, the rate of change of color change (Dt) expressed by Equation 3 can be 6.0% or less:

[0238]

Formula 3

[0239]

[0240] In Equation 3, dt0 is the time (in seconds) required for the average visible light transmittance at room temperature to decrease from 60% to 15%. 60 It is the time (in seconds) required for the average visible light transmittance to decrease from 60% to 15% after 7 days of exposure to 60°C and 60% humidity.

[0241] Specifically, the rate of change of color (Dt) refers to the time (in seconds) (dt0) required for the average visible light transmittance at room temperature to decrease from 60% to 15%, and the time (in seconds) (dt0) required for the average visible light transmittance to decrease from 60% to 15% after exposure to 60°C and 60% humidity for 7 days. 60 The absolute value of the difference between dt0 and dt0 is divided by a percentage of dt0. The value can be 5.0% or lower, 4.5% or lower, 4.0% or lower, 3.5% or lower, 3.0% or lower, 2.9% or lower, 2.8% or lower, 2.5% or lower, 2.0% or lower, 1.0% or lower, less than 1.0%, 0.9% or lower, or 0.8% or lower.

[0242] When the rate of change of color change (Dt) of the electrochromic film meets the above range, it can maintain excellent electrochromic performance even in harsh environments with high temperature and high humidity.

[0243] In Equation 3, dt0 can be 100 seconds to 165 seconds, 100 seconds to 160 seconds, 100 seconds to 155 seconds, 100 seconds to 150 seconds, 100 seconds to 145 seconds, 120 seconds to 165 seconds, 130 seconds to 165 seconds, 130 seconds to 150 seconds, 133 seconds to 145 seconds, 133 seconds to 143 seconds, or 133 seconds to 140 seconds.

[0244] In Equation 3, dt 60 The duration can be 100 to 170 seconds, 110 to 165 seconds, 110 to 160 seconds, 110 to 155 seconds, 110 to 150 seconds, 110 to 148 seconds, 120 to 165 seconds, 130 to 165 seconds, 130 to 150 seconds, 132 to 148 seconds, 133 to 147 seconds, or 133 to 145 seconds.

[0245] When dt0 and dt 60 Meeting the above-mentioned ranges may be more conducive to achieving the desired effect.

[0246] According to another implementation scheme, the time difference (Δdt) represented by the following equation 3-1 can be 10 seconds or less:

[0247]

Formula 3-1

[0248] Δdt (seconds) = │dt0 – dt 60 │

[0249] In Equation 3-1, dt0 and dt 60 The definition is as described above.

[0250] The time difference (Δdt) refers to the time (in seconds) (dt0) required for the average visible light transmittance at room temperature to decrease from 60% to 15%, compared to the time (in seconds) required for the average visible light transmittance to decrease from 60% to 15% after 7 days of exposure to 60°C and 60% humidity. 60 The absolute value of the difference between ) can be 9 seconds or less, 8 seconds or less, 7 seconds or less, 6 seconds or less, 5 seconds or less, 4 seconds or less, or 3 seconds or less.

[0251] When the time difference (Δdt) measured after the electrochromic film is exposed to 60°C and 60% humidity for 7 days meets the above range, the color change rate can be improved even in harsh environments with high temperature and high humidity.

[0252] In Equation 3-1, dt0 can be less than 170 seconds, 150 seconds or less, 143 seconds or less, or 140 seconds or less.

[0253] In equation 3-1, dt 60It can be 180 seconds or less, 150 seconds or less, 148 seconds or less, 147 seconds or less, 145 seconds or less, 140 seconds or less, or 138 seconds or less.

[0254] In equation 3-1, when dt0 and dt 60 When each of the above-mentioned ranges is met, the color change rate will be enhanced even in harsh environments with high temperature and high humidity, which may be more beneficial for achieving the desired effect.

[0255] According to another embodiment, for an electrochromic film sample with a width of 5 cm and a length of 5 cm, the thermal shrinkage rate (S) is expressed by the following formula 4. 80 It can be 2.5% or less:

[0256] Formula 4

[0257]

[0258] In Equation 4, FT0 is the initial thickness (µm) of the electrochromic film at room temperature. 80 It is the thickness (µm) of the electrochromic film after being exposed to 80°C for 7 days.

[0259] Thermal shrinkage rate (S) 80 () can be 2.0% or less, 1.8% or less, 1.5% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, or 0.6% or less.

[0260] When the thermal shrinkage rate (S) of the electrochromic film 80 When the above range is met, even in harsh environments with high temperatures of 80°C or higher, its thermal shrinkage rate can be very low, thus maintaining the performance of the electrochromic film.

[0261] In Equation 4, FT0 can be 300 μm to 400 μm, 320 μm to 400 μm, 320 μm to 380 μm, 330 μm to 360 μm, 340 μm to 360 μm, or 340 μm to 355 μm.

[0262] In Equation 4, FT 80 It can be 300 μm to 400 μm, 320 μm to 400 μm, 320 μm to 380 μm, 330 μm to 360 μm, 340 μm to 360 μm, or 340 μm to 355 μm.

[0263] In Equation 4, when FT0 and FT 80 When all of the above ranges are met, it is more conducive to achieving the expected results even in harsh environments with high temperatures of 80°C or higher.

[0264] According to another embodiment, an electrochromic film with a width of 5 cm, a length of 5 cm, and a thickness of 500 µm is immersed in a methyl ethyl ketone (MEK) organic solvent for 3 hours, and then the electrochromic film and the methyl ethyl ketone (MEK) organic solvent are removed. The amount of unreacted residue remaining may then be 40 mg or less. More specifically, it may be 30 mg or less, 20 mg or less, 10 mg or less, 5 mg or less, 3 mg or less, 2 mg or less, 1 mg or less, 0.5 mg or less, or almost nothing.

[0265] According to another implementation, when exposed to 140°C for 60 minutes, the change in haze before and after exposure can be observed with the naked eye, and the smooth and transparent shape can be maintained.

[0266] Furthermore, even in harsh environments at 140°C or higher, the electrochromic film maintains excellent color-changing performance without thermal decomposition.

[0267] Effects and applications of electrochromic films

[0268] This electrochromic film can be applied to electrochromic devices and can be further applied to smart windows in various fields such as electronic devices, automobiles, and buildings.

[0269] Electrochromic films have the property that their transmittance changes reversibly when electrical energy is applied. Therefore, with a simple operation, such as pressing a button, the transmittance of sunlight and other substances can be selectively controlled, thereby improving energy efficiency.

[0270] Specifically, when electrical energy is applied to the electrochromic film, an electric field is created between the two electrodes, resulting in coloring and fading, thereby adjusting the transmittance for each wavelength of sunlight. Therefore, it is advantageous to achieve both heat insulation and sun shading functions.

[0271] Specifically, the electrochromic film according to one embodiment comprises repeating units with a specific structure, exhibiting a significantly faster transmittance change rate compared to conventional electrochromic films. It possesses excellent heat resistance and durability, maintaining the electrolyte layer's skeletal structure from thermal decomposition and ensuring smooth lithium-ion transport even in harsh environments exceeding specific temperatures and / or humidity levels. Its transmittance change is minimal, allowing for further improvements in color-changing speed and performance. Furthermore, the electrochromic film can be manufactured at low cost in large-area electrochromic devices, and it consumes little power. Therefore, it is suitable for use as a material in smart windows, smart mirrors, or other next-generation architectural windows.

[0272] For example, electrochromic devices, including electrochromic films, can be applied by simply attaching them to structures such as conventional transparent windows. Specifically, such as Figure 9a As shown, it can be installed on one side of a window. More specifically, Figure 9b Showing along Figure 9a A cross-sectional view taken along line A-A', and an enlarged view of the portion where the electrochromic film is applied.

[0273] An electrochromic film (100) can be attached to one side of a window (10), which may be flat or curved. Furthermore, the electrochromic film (100) can be attached to the entire side of the window (10) or only to a portion of the window (10). Additionally, the electrochromic film (100) can be inserted into the window (10). Specifically, the electrochromic film can be applied by placing it between glass substrates. More specifically, it can be applied by placing two layers of polyvinyl butyral (PVB) film between the laminated glass of the window and placing the electrochromic film between the two PVB films. When heated to ensure tight adhesion, it can be stably inserted into the window.

[0274] <Preparation method of electrochromic film>

[0275] In one embodiment, a method for preparing an electrochromic film is provided, the method comprising forming a substrate layer, a conductive layer on the substrate layer, a color-changing layer on the conductive layer, and an electrolyte layer on the color-changing layer, wherein the electrolyte layer is formed using an electrolyte composition comprising a polymer resin, a lithium salt compound, and a curing modifier, and the curing modifier comprises repeating units of Formula 1 below.

[0276] Formula 1

[0277]

[0278] In Equation 1, m ranges from 1 to 20.

[0279] According to one implementation scheme, various methods can be used to prepare electrochromic films. Electrochromic films with various structures can be prepared using various methods, provided that the electrolyte layer contains repeating units of a specific structure and does not impair the desired effect.

[0280] Figure 6 A method for preparing an electrochromic film according to one embodiment is illustrated schematically.

[0281] like Figure 6As shown, a first conductive layer (131) can be formed on a first substrate layer (110) to prepare a lower plate, and a second conductive layer (139) can be formed on a second substrate layer (150) to prepare an upper plate. A first color-changing layer (133) can be formed on the first conductive layer (131) of the lower plate, and a second color-changing layer (137) can be formed on the second conductive layer (139) of the upper plate.

[0282] For example, the formation of the first conductive layer (131) and the second conductive layer (139) can be achieved by vacuum sputtering, and the formation of the first color-changing layer (133) and the second color-changing layer (137) can be achieved by wet coating. Subsequently, an electrolyte layer (135) can be formed on the first color-changing layer (133) by wet coating, and the upper and lower plates are combined together so that the electrolyte layer (135) contacts the second color-changing layer (137), thereby preparing an electrochromic film.

[0283] The electrolyte layer can be formed by coating a liquid or gel-like electrolyte composition onto the first or second color-changing layer. Specifically, the electrolyte layer (135) can be formed by coating an electrolyte composition onto one side of either the first color-changing layer (133) or the second color-changing layer (137) by wet coating, sputtering coating, or a combination of both, and then drying.

[0284] If the electrolyte layer is coated using a wet coating method, the coating thickness can be increased or the coating thickness can be easily controlled, which is beneficial for improving ionic conductivity or color change speed.

[0285] At the same time, it is possible to manufacture electrochromic devices that include electrochromic films.

[0286] Electrochromic devices can be manufactured using conventional methods. For example, copper strips can be attached to the conductive layer side of the electrochromic film to form a busbar that can be connected to a power source, thereby obtaining an electrochromic device.

[0287] <Electrolyte Composition>

[0288] In one embodiment, an electrolyte composition is provided comprising a polymer resin, a lithium salt compound, and a curing regulator, wherein the curing regulator comprises repeating units of Formula 1 above.

[0289] According to one embodiment, the electrolyte composition comprises a curing modifier having repeating units of Formula 1 above. Therefore, when electrochromic films and electrochromic devices are prepared using the electrolyte composition, their transmittance changes significantly faster compared to conventional electrochromic films. It exhibits excellent heat resistance and durability, maintaining the electrolyte layer's framework structure without thermal decomposition and ensuring smooth lithium-ion transport even in harsh environments above certain temperatures and / or humidity levels. Its transmittance change is minimal, and the color-changing speed and performance can be further improved.

[0290] The components of the electrolyte composition will be described in detail below.

[0291] polymer resin

[0292] According to one embodiment, the electrolyte composition may include a polymeric resin.

[0293] The types of polymer resins are as described above.

[0294] Specifically, the polymer resin may include acrylic resin, epoxy resin, silicone resin, polyimide resin, or polyurethane resin. Specifically, the acrylic resin may be thermosetting acrylic resin or photocurable acrylic resin, etc. The polyurethane resin may be thermosetting polyurethane resin, photocurable polyurethane resin, or waterborne polyurethane resin, etc.

[0295] The acrylic resin can be a thermosetting acrylic resin or a photocurable acrylic resin. After polymerization, the number-average molecular weight of the acrylic resin may be from 100 g / mol to 1,000,000 g / mol. Specifically, the number-average molecular weight of the acrylic resin may be from 200 g / mol to 800,000 g / mol, 300 g / mol to 650,000 g / mol, or 500 g / mol to 400,000 g / mol, but is not limited thereto. The viscosity of the acrylic resin at room temperature may be from 1,000 mPa·s to 10,000 mPa·s, specifically from 3,000 mPa·s to 9,000 mPa·s. The glass transition temperature (Tg) of the acrylic resin may be from -90°C to -10°C, specifically from -70°C to -30°C. The visible light transmittance of the acrylic resin may be 70% or higher, 80% or higher, or 90% or higher.

[0296] In addition, acrylic resins preferably contain carboxyl groups in their side chains to impart adhesiveness and compatibility with additives.

[0297] The monomer units constituting acrylic resins can be, for example, 2-ethylhexyl acrylate, methyl methacrylate, styrene, butyl acrylate, acrylamide, methacrylamide, hydroxyethyl methacrylate, methacrylic acid, itaconic acid, other monomers having monofunctional, difunctional or higher functional acrylate groups, or combinations thereof.

[0298] The weight-average molecular weight of the polymer resin can be from 15,000 g / mol to 35,000 g / mol, 18,000 g / mol to 35,000 g / mol, 18,000 g / mol to 32,000 g / mol, or 20,000 g / mol to 30,000 g / mol. The weight-average molecular weight (Mw) of the polymer resin can be determined by gel permeation chromatography (GPC).

[0299] The polydispersity (Mw / Mn) of the polymer resin can be 1.0 to 4.0, 1.5 to 3.5, 2.0 to 3.0, 2.5 to 3.5, or 2.5 to 3.0. Polydispersity can be determined by gel permeation chromatography (GPC).

[0300] lithium salt compounds

[0301] According to one embodiment, the electrolyte composition may include a lithium salt compound.

[0302] The types of lithium salt compounds are as described above.

[0303] The content of the lithium salt compound relative to 100 parts by weight of the polymer resin can be 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, or 20 parts by weight or more, and less than 50 parts by weight, less than 45 parts by weight, less than 40 parts by weight, or less than 30 parts by weight. As a specific embodiment, the content of the lithium salt compound relative to 100 parts by weight of the polymer resin, such as acrylic resin, can be 10 to 50 parts by weight, 10 to 40 parts by weight, or 10 to 35 parts by weight.

[0304] Lithium salt compounds can be used alone or in combination of two or more lithium salt compounds.

[0305] When lithium salt compounds are used alone, for example, the amount of lithium salt compound used relative to 100 parts by weight of polymer resin can be from 10 parts by weight to 40 parts by weight.

[0306] When lithium salt compounds are used in combination, for example, LITFSI and LiPF6 can be mixed in a ratio of 9:1 to 1:9, and the amount of lithium salt compound used relative to 100 parts by weight of polymer resin can be from 10 parts by weight to 40 parts by weight.

[0307] The above content ranges may be based on the content of non-volatile components.

[0308] Since lithium salt compounds are typically in solid crystalline form, they can be dissolved by adding a polar solvent to the electrolyte. Polar solvents can be, for example, methyl ethyl ketone, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, ethyl propionate, methyl propionate, isopropanol, and acetone. The amount of polar solvent used relative to 100 parts by weight of the lithium salt compound can be 40 to 80 parts by weight, or 50 to 70 parts by weight.

[0309] Curing regulator

[0310] According to one embodiment, the electrolyte composition may include a curing regulator.

[0311] Curing regulators can prevent over-curing by controlling the degree of curing of polymer resins, while maintaining the skeletal structure of the electrolyte layer in the electrochromic film and ensuring lithium ion channels.

[0312] According to one embodiment, the curing modifier is an aromatic oligomer or polymer with a structure different from that of the polymer resin, and is a compound containing binaphthol, for example, 1,1'-binaphthol, in repeating units.

[0313] The curing modifier can create sufficient space between the two naphthol-linked structures, allowing for smooth lithium ion transport and thus stably maintaining the electrolyte layer structure and ensuring the lithium ion transport pathway. Furthermore, heat resistance and durability can be further improved. In particular, when the curing modifier contains the aforementioned compounds, it can strengthen the electrolyte layer, thus maintaining excellent electrochromic properties even after exposure to harsh environments.

[0314] Specifically, a curing modifier according to one embodiment may contain repeating units of Formula 1 above: the structural features of the repeating units of Formula 1 above are as described above.

[0315] When the curing modifier contains repeating units of the specific structure described above, it may be beneficial to achieve the desired effect; in particular, it can improve the durability, heat resistance and color change rate of the electrochromic film.

[0316] Furthermore, the curing modifier may further include repeating units of Formula 2 above: the structural features of the repeating units of Formula 2 above are as described above.

[0317] Furthermore, the curing modifier may contain repeating units of Formula 3 above: the structural features of the repeating units of Formula 3 above are as described above.

[0318] The weight-average molecular weight of the curing modifier can be from 1,500 g / mol to 6,000 g / mol, 2,000 g / mol to 5,000 g / mol, 2,500 g / mol to 4,500 g / mol, 2,500 g / mol to 4,000 g / mol, or 3,000 g / mol to 4,000 g / mol.

[0319] Furthermore, in one specific embodiment, the weight-average molecular weight of the curing regulator can be from 1,500 g / mol to 6,000 g / mol, and the weight-average molecular weight of the polymer resin can be from 15,000 g / mol to 35,000 g / mol.

[0320] When the weight-average molecular weight of the curing modifier meets the above range, its solubility and compatibility are excellent, and its heat resistance and durability can be further improved.

[0321] If the weight-average molecular weight of the curing modifier exceeds the above range, its solubility and compatibility may deteriorate. If the molecular weight of the curing modifier is less than the above range, its heat resistance and durability under high temperature and high humidity conditions may be insufficient.

[0322] The weight-average molecular weight of the curing modifier can be 20% or less, 15% or less, or 10% or less of the molecular weight of the polymer resin, and can also be 5% or more, or 8% or more of the molecular weight of the curing modifier. The molecular weight of the curing modifier can be 5% to 20%, 5% to 18%, 8% to 18%, or 8% to 15% of the molecular weight of the polymer resin.

[0323] Furthermore, when the curing modifier contains repeating units of Formula 1 with aromatic structures and the polymer resin contains aliphatic compounds, the curing modifier and the polymer resin have different structures, thus exhibiting excellent compatibility. Therefore, it can provide a stable space for the electrolyte layer skeleton, which helps the smooth transport of lithium ions and enhances heat resistance and durability.

[0324] For example, when the polymer resin contains aliphatic compounds, the polymer resin may shrink upon heating, which may reduce the space for lithium-ion transport. Therefore, especially in harsh environments with high temperature and humidity, this shrinkage may hinder lithium-ion transport, thereby reducing the color-changing rate. However, when a curing modifier comprising repeating units of Formula 1 according to one embodiment is added, sufficient lithium-ion transport space can be ensured in the electrolyte layer, and thermal curing of the polymer resin can be prevented, thereby maintaining excellent electrochromic properties.

[0325] The polydispersity of the curing regulator can be 1.0 to 5.0, 1.0 to 4.0, 1.0 to 3.5, 1.5 to 3.0 or 2.0 to 3.0.

[0326] As a specific example, the molecular weight of the curing regulator may be 20% or less of the molecular weight of the polymer resin, and the polydispersity is 1.0 to 5.0.

[0327] When the weight-average molecular weight and / or polydispersity of the curing regulator meet the above ranges, it may be more conducive to achieving the desired effect.

[0328] Weight-average molecular weight and polydispersity can be determined by gel permeation chromatography (GPC).

[0329] The content of the curing modifier relative to 100 parts by weight of polymer resin can be from 1 part by weight to 20 parts by weight. Specifically, the content of the curing modifier can be from 1 part by weight to 15 parts by weight, 1 part by weight to 12 parts by weight, 1 part by weight to 10 parts by weight, 1 part by weight to 8 parts by weight, 1 part by weight to 6 parts by weight, 1 part by weight to 5 parts by weight, 2 parts by weight to 20 parts by weight, 2 parts by weight to 15 parts by weight, 2 parts by weight to 12 parts by weight, 2 parts by weight to 10 parts by weight, 2 parts by weight to 8 parts by weight, 2 parts by weight to 6 parts by weight, 2 parts by weight to 5 parts by weight, 3 parts by weight to 20 parts by weight, 3 parts by weight to 15 parts by weight, 3 parts by weight to 12 parts by weight, 3 parts by weight to 10 parts by weight, and so on. Parts by weight, 3 to 8 parts by weight, 3 to 6 parts by weight, 3 to 5 parts by weight, 5 to 20 parts by weight, 5 to 15 parts by weight, 5 to 12 parts by weight, 5 to 10 parts by weight, 5 to 8 parts by weight, 8 to 20 parts by weight, 8 to 15 parts by weight, 8 to 12 parts by weight, 8 to 10 parts by weight, 10 to 20 parts by weight, 10 to 15 parts by weight, 10 to 12 parts by weight, 15 to 20 parts by weight, or 15 to 18 parts by weight.

[0330] When the content of the curing modifier meets the above range, the heat resistance of the electrolyte layer can be improved, and it has excellent durability in high temperature and high humidity environments, thereby improving the color-changing performance, such as the color-changing speed.

[0331] If the content of the curing modifier exceeds the above range, thermal decomposition or side reactions may occur at temperatures of 60°C or higher, or 80°C or higher, and the curing modifier may not bond firmly to the polymer resin, thus reducing the curing effect. Furthermore, if the concentration of the curing modifier is below the above range, the expected effect may be negligible.

[0332] According to one embodiment, a method for preparing a curing modifier may include, for example, dissolving 1,1'-bi-2-naphthol, phenol and 1,3,5-trioxane in a first solvent, then adding p-toluenesulfonic acid monohydrate to obtain a curing modifier solution; and reacting the curing modifier solution.

[0333] The first solvent may include at least one selected from the group consisting of propylene glycol monomethyl ether acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol n-butyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether acetate, diethylene glycol methyl ethyl ether, diethylene glycol ethyl ether acetate, dipropylene glycol n-butyl ether, tripropylene glycol n-propyl ether, tripropylene glycol methyl ether, propylene glycol diacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether acetate, cyclohexanone, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, and ethyl 3-ethoxypropionate.

[0334] The above reaction may be a phenol-formaldehyde reaction. A curing regulator can be obtained through the above reaction, which contains a repeating unit of Formula 1 above, wherein the repeating unit contains at least one repeating unit of 1,1'-bi-2-naphthol linked to a methylene (CH2) group.

[0335] For example, the reaction is maintained at about 60°C to 200°C, about 60°C to 150°C, or about 80°C to 120°C for about 10 minutes to 5 hours, about 30 minutes to 4 hours, about 30 minutes to 3 hours, or about 30 minutes to 2 hours.

[0336] In addition, after the reaction is complete, the product is slowly cooled to room temperature to terminate the reaction. The product is then added dropwise to the solvent with stirring. The resulting chemical reaction product condenses on the bottom surface of the flask. It is then separated from the supernatant and dried to obtain the curing regulator.

[0337] As long as it contains the repeating units mentioned above, the curing regulator can be prepared by various methods, and is not limited to the preparation methods described above.

[0338] Furthermore, according to one embodiment, a curing modifier containing repeating units of Formula 1 above can be prepared and used in an electrolyte composition.

[0339] According to another embodiment, a curing modifier containing repeating units of Formula 3 above can be prepared and used in an electrolyte composition.

[0340] According to another embodiment, a first curing modifier containing repeating units of Formula 1 and a second curing modifier containing repeating units of Formula 2 are prepared, and the first curing modifier and the second curing modifier are combined to prepare a mixed curing modifier, which can be used in an electrolyte composition.

[0341] Meanwhile, the method for preparing the electrolyte composition may include (1) dissolving a lithium salt compound in a second solvent to prepare a solution containing a lithium salt; (2) adding a polymer resin to the solution to prepare a resin mixture; and (3) adding a curing modifier to the resin mixture and mixing the mixture.

[0342] The second solvent may include at least one solvent selected from the group consisting of ethanol, methyl ethyl ketone, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, ethyl propionate, methyl propionate, isopropanol, and acetone.

[0343] The specific types and quantities of raw materials used in steps (1) to (3) are shown above.

[0344] The mixing in step (2) can be carried out at room temperature, for example, by stirring at a speed of 300 rpm to 700 rpm for 10 minutes to 1 hour until the mixture becomes transparent.

[0345] In addition, the mixing in step (3) can be carried out at room temperature to 60°C, for example, by stirring at a speed of 300 rpm to 700 rpm for 30 minutes to 2 hours until the mixture becomes transparent.

[0346] Invention Model

[0347] The present invention will now be described in more detail with reference to the following embodiments. However, these embodiments are provided for the purpose of describing the present invention, and the scope of the present invention is not limited thereto.

[0348] Preparation Example 1: Preparation of Curing Conditioner

[0349] Preparation Example 1-1

[0350] Step 1-1: Prepare a 500ml three-necked round-bottom flask equipped with a thermometer, condenser (reflux condenser), dropping funnel, and mechanical stirrer, and immerse it in a thermostat at approximately 100°C. Add 43.0g of 1,1'-bi-2-naphthol, 14.1g of phenol, and 35.1g of 1,3,5-trioxane dissolved in approximately 150g of propylene glycol monomethyl ether acetate to the flask. Add 2.85g of p-toluenesulfonic acid monohydrate to the flask.

[0351] Step 1-2: After the addition in Step 1-1 is completed, the reactor temperature is maintained at approximately 100°C. While the reaction proceeds, a sample is taken from the reaction mixture and the weight-average molecular weight (Mw) of the sample is measured. When the desired weight-average molecular weight is reached, this is determined as the completion point of the reaction, and the reaction mixture is gradually cooled at room temperature to terminate the reaction.

[0352] Steps 1-3: The product from Steps 1-2 was added dropwise to approximately 800 g of ethanol while stirring. The resulting chemical reaction product condensed at the bottom of the flask and was separated from the supernatant. The resulting product was dried in a vacuum oven at approximately 80°C to remove residual solvent and impurities, thus obtaining the curing regulator. The curing regulator was determined by gel permeation chromatography (GPC). The weight-average molecular weight was approximately 3,200 g / mol, the polydispersity was approximately 1.9, and the molar ratio of repeating units in Formula 1 to repeating units in Formula 2 was 100:25.

[0353] Preparation Examples 1-2

[0354] Except for changing the amounts of 1,1'-bi-2-naphthol, phenol, and 1,3,5-trioxane to make the molar ratio of the repeating units of Formula 1 to Formula 2 in the electrolyte layer 100:20, the curing modifier was obtained by the same method as in Preparation Example 1-1.

[0355] Preparation Examples 1-3

[0356] Except for changing the amounts of phenol and 1,3,5-trioxane, and omitting 1,1'-bi-2-naphthol, so that the molar ratio of the repeating units of Formula 1 to Formula 2 in the electrolyte layer is 0:100, the curing modifier was obtained by the same method as in Preparation Example 1-1.

[0357] Preparation Example 2: Preparation of Polymer Resin

[0358] Step 2-1: Prepare a 1L three-necked round-bottom flask equipped with a thermometer, condenser (reflux condenser), dropping funnel, and mechanical stirrer, and immerse it in a thermostat at approximately 90°C. Add approximately 300g of ethyl acetate and approximately 1.5g of azobisisobutyronitrile (AIBN) to the flask as free radical polymerization initiators, and stir with the mechanical stirrer at a speed of 100 rpm. Here, the temperature of the condenser is maintained at approximately 10°C.

[0359] Step 2-2: In another flask, add approximately 63 parts by weight (approximately 189 g) of butyl acrylate, approximately 9 parts by weight (approximately 27 g) of methyl methacrylate, approximately 17 parts by weight (approximately 51 g) of 2-hydroxyethyl acrylate, and approximately 10 parts by weight (approximately 30 g) of p-dodecylstyrene (C 20 H 32 Stir with a mechanical stirrer for about 30 minutes. Then, slowly add it to the flask from step 2-1 using a dropping funnel.

[0360] Steps 2-3: After the addition is complete, the reactor temperature is maintained at approximately 90°C. While the reaction proceeds, a sample is taken from the reaction mixture, and the weight-average molecular weight (Mw) of the sample is measured. When the desired weight-average molecular weight is reached, this is determined as the completion point of the reaction, and the reaction mixture is gradually cooled at room temperature to terminate the reaction. The resulting compound (a liquid acrylic resin) is determined by gel permeation chromatography (GPC). The weight-average molecular weight is approximately 26,000 g / mol, and the polydispersity is approximately 2.7.

[0361] Example 1

[0362] Preparation of electrolyte composition

[0363] About 10 parts by weight (about 100 g) of LITFSI (lithium bis(trifluoromethane)sulfonylimide) and about 25 parts by weight (about 250 g) of LiPF6 lithium salt compound were added to about 50 parts by weight (about 500 g) of propylene carbonate and about 15 parts by weight (about 150 g) of ethyl propionate relative to 100 parts by weight of polymer resin, and dissolved at about 40°C to obtain a solution containing lithium salt.

[0364] Approximately 40 g of the polymer resin obtained in Preparation Example 2 was added to 160 g of the above solution and mixed. Then, 3 parts by weight of the curing conditioner obtained in Preparation Examples 1-1, relative to 100 parts of the polymer resin, were added to the mixture. The mixture was mixed at room temperature to obtain the electrolyte composition.

[0365] Preparation of electrochromic films

[0366] Two transparent electrode substrates were fabricated, wherein a primer layer, a barrier layer, and an ITO electrode (surface resistivity of 50 Ω / sq) as a conductive layer were formed on a PET substrate layer (thickness: 125 μm), and these substrates were used as the upper and lower plates. In this case, the combined thickness of the primer layer and the barrier layer was approximately 2 μm, and the thickness of the conductive layer was approximately 100 nm.

[0367] Tungsten oxide (WO3) slurry was coated onto the ITO conductive layer of the lower plate by wet coating and dried at 140°C for 5 minutes to form a reduction color-changing layer (thickness: 600 nm).

[0368] In addition, Prussian blue pigment was coated onto the ITO conductive layer of the upper plate by wet coating and dried at 140°C for 5 minutes to form an oxide color-changing layer (thickness: 400 nm).

[0369] The electrolyte composition was coated onto the reductive color-changing layer of the lower plate and dried at about 130°C for 2 minutes to form an electrolyte layer (drying thickness of about 100 μm) having the molar ratio of repeating units of Formula 1 to repeating units of Formula 2 as shown in Table 1 below.

[0370] The upper and lower plates are assembled together so that the oxidized color-changing layer is on the electrolyte layer. Then, they are placed in an oven and cured at 130°C for 2 minutes to obtain an electrochromic film with a width of 300 mm, a length of 500 mm, and a thickness of 500 μm.

[0371] Fabrication of electrochromic devices

[0372] A copper strip is connected to the side of the ITO conductive layer on the upper and lower plates of the electrochromic film to form a busbar that can be connected to a power source, thereby obtaining an electrochromic device.

[0373] The edges of the electrochromic device are sealed with silicone sealant.

[0374] Example 2

[0375] Except for the electrolyte composition obtained by adding 5 parts by weight of the curing modifier obtained in Preparation Examples 1-1 relative to 100 parts by weight of polymer resin, as shown in Table 1 below, electrochromic films and electrochromic devices were obtained by the same method as in Example 1.

[0376] Example 3

[0377] Except for the electrolyte composition obtained by adding 10 parts by weight of the curing modifier obtained in Preparation Examples 1-2 relative to 100 parts by weight of polymer resin as shown in Table 1 below, electrochromic films and electrochromic devices were obtained by the same method as in Example 1.

[0378] Example 4

[0379] Except for the electrolyte composition obtained by adding 15 parts by weight of the curing modifier obtained in Preparation Examples 1-2 relative to 100 parts by weight of polymer resin as shown in Table 1 below, electrochromic films and electrochromic devices were obtained by the same method as in Example 1.

[0380] Example 5

[0381] Except for the electrolyte composition obtained by adding 20 parts by weight of the curing modifier obtained in Preparation Examples 1-1 relative to 100 parts by weight of polymer resin as shown in Table 1 below, electrochromic films and electrochromic devices were obtained by the same method as in Example 1.

[0382] Comparative Example 1

[0383] The upper and lower plates are assembled together so that the oxidized color-changing layer is on top of the reduced color-changing layer, as shown in Table 1 below. Then, they are placed in an oven and cured at 130°C for 2 minutes to obtain an electrochromic film with a width of 300 mm, a length of 500 mm, and a thickness of 400 μm.

[0384] Comparative Example 2

[0385] Except for the electrolyte composition obtained by adding 5 parts by weight of the curing modifier obtained in Preparation Examples 1-3 relative to 100 parts by weight of polymer resin as shown in Table 1 below, electrochromic films and electrochromic devices were obtained by the same method as in Example 1.

[0386] Evaluation of Implementation Examples

[0387] Evaluation of Example 1: Transmission Characteristics of Electrochromic Film

[0388] The following tests were performed on the electrochromic films prepared in the examples and comparative examples.

[0389] A. Measuring device

[0390] - Fluke 175 True RMS multimeter for electrical measurements.

[0391] - Toyotech's DP-30 is for power supplies.

[0392] - The SD 2400 from EDTM, Inc. in the United States is used for transmittance measurement.

[0393] B. Samples: Electrochromic films of Examples 1 to 5 and Comparative Examples 1 and 2, having dimensions of 300 mm in width, 500 mm in length, and 500 µm in thickness.

[0394] C. Detection Method

[0395] (1) Initialization: Apply a voltage of 2.4 V to each sample at room temperature to achieve the maximum fading effect.

[0396] (2) Coloration test: Apply a voltage of -1.2 V to the sample in the maximum fading state to make it return to the maximum coloration state. Measure the transmittance over time.

[0397] (3) Fading test: Apply a voltage of 1.2 V to the sample in the maximum coloring state to make it change to the maximum fading state. Measure the transmittance over time.

[0398] (4) Repeat steps (2) and (3) as needed to perform the test.

[0399] D. Transmittance measurement

[0400] See Figure 7 and 8 The electrochromic film (100) sample is placed between the light source (210) and the measuring device (220). The visible light transmittance of the center point (P1) and four edge points (P2, P3, P4 and P5) is measured in the wavelength range of about 30 nm to 60 nm. 30 mm is removed from each end of the electrochromic film (100) sample, and the average visible light transmittance value of P1 to P5 is taken.

[0401] Meanwhile, the above method was used to evaluate various transmission characteristics of the electrochromic film samples.

[0402] - Transmittance difference at maximum tinting condition (ΔT60) dis )

[0403] For each electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, the average visible light transmittance was measured under the maximum coloring state, and the transmittance difference (ΔT60) under the maximum coloring state was calculated as expressed by Equation 1-1 below. dis ):

[0404] Equation 1-1

[0405] ΔT60 dis (%) = |T dis0 – T dis60 │

[0406] In Equation 1-1, T dis0 The initial transmittance (%) of the sample under maximum coloration conditions, measured at room temperature, is T. dis60 The transmittance (%) of the sample under maximum coloration is measured after 7 days of exposure to 60°C and 60% humidity.

[0407] The results are shown in Table 2 below.

[0408] - Transmittance difference under maximum fading condition (ΔT60) de )

[0409] For each electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, the average visible light transmittance was measured under the maximum fading state, and the transmittance difference (ΔT60) under the maximum fading state was calculated as expressed by Equation 1-2 below. de ).

[0410]

Formula 1-2

[0411] ΔT60 de (%) = |T de0 – T de60│

[0412] In Equation 1-2, T de0 The initial transmittance (%) of the sample under the maximum fading state, measured at room temperature, is T. de60 The transmittance (%) of the sample under maximum fading condition was measured after 7 days of exposure to 60°C and 60% humidity.

[0413] The results are shown in Table 2 below.

[0414] - Transmittance difference at maximum tinting condition (ΔT80) dis )

[0415] Furthermore, for each electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, the average visible light transmittance was measured under the maximum coloring state, and the transmittance difference (ΔT80) under the maximum coloring state was calculated as expressed by Equation 2-1 below. dis ).

[0416] Equation 2-1

[0417] ΔT80 dis (%) = |T dis0 – T dis80 │

[0418] In Equation 2-1, T dis0 The initial transmittance (%) of the sample under maximum coloration conditions, measured at room temperature, is T. dis80 The transmittance (%) of the sample under maximum coloration is measured after 7 days of exposure to 80°C.

[0419] The results are shown in Table 3 below.

[0420] - Transmittance difference under maximum fading condition (ΔT80) de )

[0421] For each electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, the average visible light transmittance was measured under the maximum fading state, and the transmittance difference (ΔT80) under the maximum fading state was calculated as expressed by Equation 2-2 below. de ).

[0422]

Formula 2-2

[0423] ΔT80 de (%) = |T de0 – T de80 │

[0424] In Equation 2-2, T de0The initial transmittance (%) of the sample under the maximum fading state, measured at room temperature, is T. de80 The transmittance (%) of the sample under maximum fading condition was measured after 7 days of exposure to 80°C.

[0425] The results are shown in Table 3 below.

[0426] - Rate of change of color change (Dt)

[0427] For each electrochromic film sample with a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, calculate the rate of change of color change (Dt) as expressed by Equation 3 below.

[0428]

Formula 3

[0429]

[0430] In Equation 3, dt0 is the time (in seconds) required for the average visible light transmittance at room temperature to decrease from 60% to 15%, and dT is the time (in seconds) required for the average visible light transmittance to decrease from 60% to 15%. 60 It is the time (in seconds) required for the average visible light transmittance to decrease from 60% to 15% after 7 days of exposure to 60°C and 60% humidity.

[0431] The results are shown in Table 4 below.

[0432] - Time difference (Δdt)

[0433] Using dt0 and dt 60 The time difference (Δdt) represented by the following formula 3-1 is calculated.

[0434]

Formula 3-1

[0435] Δdt (seconds) = │dt0 – dt 60 │

[0436] In Equation 3-1, dt0 and dt60 are defined as described above.

[0437] The results are shown in Table 4 below.

[0438] However, if the samples are not exactly the same, the initial transmittance may differ due to the different preparation and measurement variables for each sample.

[0439] Evaluation of Example 2: Thermal shrinkage rate (S) of electrochromic film 80 )

[0440] For an electrochromic film sample with a width of 5 cm and a length of 5 cm, the initial thickness (µm) of the electrochromic film at room temperature and the thickness (µm) after exposure to 80°C for 7 days were measured, and the thermal shrinkage rate (S) expressed by Equation 4 was rated. 80):

[0441] Formula 4

[0442]

[0443] In Equation 4, FT0 is the initial thickness (µm) of the electrochromic film at room temperature. 80 It is the thickness (µm) of the electrochromic film after being exposed to 80°C for 7 days.

[0444] The results are shown in Table 5 below.

[0445] Evaluation Example 3: Shape Changes of Electrochromic Films under Harsh Environments such as High Temperature and High Humidity

[0446] Electrochromic films with dimensions of 5 cm wide, 5 cm long, and 400 µm thick, obtained from the examples and comparisons, were exposed to 140°C for 60 minutes, and the shape changes of the electrochromic films before and after exposure were observed with the naked eye. The results are shown in Table 6 below.

[0447] Evaluation of Example 4: Residual Amount

[0448] The electrochromic films obtained in the examples and comparative examples were cut into 5 cm wide and 5 cm long pieces, respectively, and immersed in methyl ethyl ketone (MEK) organic solvent for 3 hours, followed by shaking for 3 hours. The solution was transferred to a flask and completely evaporated using a vacuum evaporator to remove the electrochromic film and methyl ethyl ketone (MEK) organic solvent. The amount of remaining unreacted residue was determined. The results are shown in Table 6 below.

[0449] Table 1

[0450]

[0451] Table 2

[0452]

[0453] Table 3

[0454]

[0455] As can be seen from Tables 2 and 3 above, the electrochromic films containing repeating units of Formula 1 in Examples 1 to 5 have a strong electrolyte layer framework structure. Therefore, even when exposed to harsh environments with a temperature of 60°C and humidity of 60% or 80°C for 7 days or longer, the difference in transmittance between the maximum colored state and the faded state is very small. Moreover, even under harsh environments, the transmittance can be maintained at a certain level or higher. In contrast, the electrochromic film without an electrolyte layer in Comparative Example 1 and the electrochromic film with repeating units containing an electrolyte layer of Formula 2 in Comparative Example 2 do not have this advantage.

[0456] Meanwhile, although the electrochromic film in Comparative Example 2 using the repeating unit electrolyte layer of Formula 2 is slightly improved compared to the electrochromic film in Comparative Example 1 without the electrolyte layer, its light transmittance is lower than that of the electrochromic films in Examples 1 to 5.

[0457] It is understood that in the electrochromic film of Comparative Example 2, which uses an electrolyte layer containing repeating units of Formula 2, the lack of large-volume repeating units of Formula 1 makes it difficult to form a space conducive to lithium-ion transport within the electrolyte layer, and the insufficient heat resistance causes its projection performance to decrease depending on the content of curing regulator.

[0458] Table 4

[0459]

[0460] As can be seen from Table 4 above, in the electrochromic films of Examples 1 to 5, the electrolyte layer includes the repeating unit of Formula 1. At a temperature of 60°C and a humidity of 60%, the color change rate from 60% to 15% is improved. Even after exposure to harsh environments for 7 days, the rate of change of color change is lower than that of the electrochromic film without an electrolyte layer in Comparative Example 1 and the electrochromic film with an electrolyte layer including the repeating unit of Formula 2 in Comparative Example 2.

[0461] Table 5

[0462]

[0463] As can be seen from Table 5 above, in the electrochromic films of Examples 1 to 5, the electrolyte layer contains the repeating unit of Formula 1. Even when exposed to a harsh environment of 80°C for 7 days, its thermal shrinkage rate is significantly lower than that of the electrochromic film without an electrolyte layer in Comparative Example 1 and the electrochromic film with an electrolyte layer containing repeating units of Formula 2 in Comparative Example 2.

[0464] Table 6

[0465]

[0466] As can be seen from Table 6 above, the electrochromic films containing repeating units of Formula 1 in Examples 1 to 5 exhibit very low thermal decomposition. Even after exposure to a harsh environment of 140°C for 60 minutes, they still maintain a smooth and transparent shape, with a residual amount of 17 mg or less, and in most cases, the residual amount is almost zero. The electrochromic films without an electrolyte layer in Comparative Example 1 and the electrochromic films with repeating units containing an electrolyte layer of Formula 2 in Comparative Example 2 do not exhibit this phenomenon.

Claims

1. An electrochromic film comprising a substrate layer, a conductive layer, a color-changing layer, and an electrolyte layer, wherein, The electrolyte layer includes a repeating unit of the following Formula 1: 【Formula 1】 ； In Formula 1, m is 1 to 20. 2.The electrochromic film of claim 1, wherein the electrolyte layer comprises a repeating unit of the following Formula 2: 【Formula 2】 ； In Formula 2, A is an aromatic group, n is 1 to 30, and x is 1 or 2. 3.The electrochromic film of claim 2, wherein the electrolyte layer comprises the repeating unit of the above Formula 1 and the repeating unit of the above Formula 2 in a molar ratio of 100:0 to 100:

50. 4.The electrochromic film of claim 1, wherein, for an electrochromic film sample having a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, When the average visible light transmittance is measured in the maximum tint state, the transmittance difference (ΔT60 dis ) in the maximum tint state represented by Equation 1-1 below is less than 3.5%, and The difference in transmittance in the maximum faded state (ΔT60 de ) is 1.2% or less when the average visible light transmittance is measured in the maximum faded state by the following Equation 1-2: [Formula 1-1] ΔT60 dis (%) = |T dis0 – T dis60 |; In formula 1-1, T dis0 is the initial transmittance of the sample in the most colored state (%), measured at room temperature, T dis60 is the transmittance of the sample in the most colored state (%), measured after 7 days of exposure to a temperature of 60°C and a humidity of 60%. [Formula 1-2] ΔT60 de (%) = |T de0 – T de60 |; In formula 1-2, T de0 is the initial transmission of the sample in the maximum faded state (%), measured at room temperature, T de60 is the transmission of the sample in the maximum faded state (%), measured after 7 days of exposure to a temperature of 60°C and a humidity of 60%. 5.The electrochromic film of claim 1, wherein, for an electrochromic film sample having a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, When the average visible light transmittance is measured in the maximum tint state, the transmittance difference (ΔT80 dis ) in the maximum tint state represented by Equation 2-1 below is 6.0% or less, and The difference in transmittance in the maximum faded state (ΔT80 de ) represented by Equation 2-2 below is 2.0% or less when the average visible light transmittance is measured in the maximum faded state: [Formula 2-1] ΔT80 dis (%) = |T dis0 – T dis80 |; In formula 2-1, T dis0 is the initial transmittance of the sample in the most colored state (%), measured at room temperature, T dis80 is the transmittance of the sample in the most colored state (%), measured after exposure to a temperature of 80°C for 7 days, [Formula 2-2] ΔT80 de (%) = |T de0 - T de80 |; In formula 2-2, T de0 is the initial transmittance (%) of the sample in the maximum faded state measured at room temperature, T de80 is the transmittance (%) of the sample in the maximum faded state measured after exposure to a temperature of 80°C for 7 days. 6.The electrochromic film of claim 1, wherein, for an electrochromic film sample having a width of 300 mm, a length of 500 mm, and a thickness of 500 µm, The color change rate (Dt) represented by the following Formula 3 is 6.0% or less: 【Formula 3】 ； In formula 3, dt0 is the time (seconds) required for the average visible light transmittance to decrease from 60% to 15% at room temperature, dt 60 is the time (seconds) required for the average visible light transmittance to decrease from 60% to 15% after exposure to a temperature of 60°C and a humidity of 60% for 7 days. 7.The electrochromic film of claim 6, wherein the time difference (Δdt) represented by the following Formula 3-1 is 10 seconds or less: 【Formula 3-1】 Δdt (sec) = |dto - dt 60 |; In formula 3-1, dt0and dt 60 each as defined in claim 6.

8. The electrochromic film of claim 1, wherein a heat shrinkage (S 80 ) represented by the following formula 4 is 2.5% or less for an electrochromic film sample having a width of 5 cm and a length of 5 cm: S = (L - L0) / L0 x 100 (4) where L0 is the length of the electrochromic film sample before heat treatment, and L is the length of the electrochromic film sample after heat treatment. 【Formula 4】 ； In formula 4, FT0is the initial thickness of the electrochromic film at room temperature (pm), FT 80 is the thickness of the electrochromic film after exposure to 80°C for 7 days (pm). 9.The electrochromic film of claim 1, wherein, when an electrochromic film having a width of 5 cm, a length of 5 cm, and a thickness of 500 µm is immersed in a methyl ethyl ketone (MEK) organic solvent for 3 hours, and the electrochromic film and the methyl ethyl ketone (MEK) organic solvent are taken out, the amount of residual unreacted residue remaining is 40 mg or less. 10.A method of manufacturing an electrochromic film, comprising forming a base layer, a conductive layer on the base layer, a color-changing layer on the conductive layer, and an electrolyte layer on the color-changing layer, wherein, The electrolyte layer is formed from an electrolyte composition including a polymer resin, a lithium salt compound, and a curing adjuster, wherein the curing adjuster includes a repeating unit of the following Formula 1: 【Formula 1】 ； In Formula 1, m is 1 to 20. 11.An electrolyte composition including a polymer resin, a lithium salt compound, and a curing adjuster, wherein the curing adjuster includes a repeating unit of the following Formula 1: 【Formula 1】 ； In Formula 1, m is 1 to 20. 12.The electrolyte composition of claim 11, wherein the content of the curing adjuster is 1 to 20 parts by weight with respect to 100 parts by weight of the polymer resin. 13.The electrolyte composition of claim 11, wherein the molecular weight of the curing adjuster is 20% or less of the molecular weight of the polymer resin, and the polydispersity is 1.0 to 5.

0. 14.The electrolyte composition of claim 11, wherein the weight average molecular weight of the curing adjuster is 1,500 g / mol to 6,000 g / mol, and the weight average molecular weight of the polymer resin is 15,000 g / mol to 35,000 g / mol.

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