KR102397860B1 - Flexible electrochromic device - Google Patents

Abstract

The electrochromic device according to an embodiment includes a first base layer, a second base layer, and a light-transmitting variable structure disposed therebetween, and is repeatedly bent or maintained in a bent state for a long time, or power is cut off for a long time. Even in this case, there is little change in transmittance compared to the initial stage, and the transmittance operation function can be maintained as it is.

Description

Flexible electrochromic device {FLEXIBLE ELECTROCHROMIC DEVICE}

It relates to an electrochromic device that realizes an excellent light transmittance variable function based on the electrochromic principle and at the same time has flexibility.

Recently, as interest in environmental protection increases, interest in technology to improve energy efficiency is also increasing. For example, research and development of technologies such as smart windows and energy harvesting are being actively conducted. Among them, the smart window refers to an active control technology that can improve energy efficiency and provide a comfortable environment to users by adjusting the degree of transmission of light coming from the outside, and is a basic technology that can be commonly applied to various industrial fields. . These smart windows use electrochromism as a basic principle, which is a phenomenon in which an electrochemical oxidation or reduction reaction occurs by an applied power, and, accordingly, optical properties such as the intrinsic color or light transmittance of the electrochromic active material are changed. .

Currently, a glass-type smart window with an electrochromic element applied between several sheets of glass is generally used, but the manufacturing process is complicated and the product price is very expensive because it has to be manufactured according to the size of the window to be installed, so it is difficult to commercialize it. There are difficulties. In addition, in the case of silicone finishing, there is a risk of short circuit because moisture can penetrate, and it takes up a lot of loading space during logistics movement, and at the same time, there is a problem that it is dangerous because it is easy to break due to external impact due to the nature of the material such as glass.

Accordingly, research on a smart window capable of solving the above problem and implementing an excellent light transmittance variable function is continuously required.

The embodiment intends to provide an electrochromic device having flexibility while implementing an excellent light transmittance variable function based on the electrochromic principle.

According to one embodiment, a first discoloration comprising a first base layer, a second base layer, and a light-transmitting variable structure disposed therebetween, wherein the light-transmitting variable structure is adjustable in color and discoloration according to the application of power. An electrochromic element including a layer, based on the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length, in a test in which the distance between both ends in the horizontal direction is 75 mm for a certain period of time in a bent state Here, an electrochromic element having a fourth transmittance change (ΔTT_100H) defined in Equation (4) below 3% is provided:

△TT_100H (%) = │TT_100H - TT_0│ ... (4)

In Equation (4), TT_100H is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after performing the sustain test for 100 hours, and TT_0 is the measured in the maximum discoloration state before the sustain test It is the average visible light transmittance (%) of the electrochromic element.

The electrochromic device according to the embodiment has a flexible characteristic while realizing an excellent light transmittance variable function based on the electrochromic principle. In particular, when the electrochromic device according to the embodiment is repeatedly bent or maintained in a bent state for a long time or when the power is cut off for a long time, there is little change in transmittance compared to the initial stage, and the transmittance operation function can be maintained as it is.

Accordingly, the electrochromic device can be applied to a curved window without performance degradation, and can be applied to a curved part or a large moving part in the fields of electronic devices, automobiles, architecture, and the like. In addition, the electrochromic element can be wound in the form of a roll using its flexible characteristics, which can provide convenience in the manufacturing process, transportation, installation, etc., and can be easily cut and attached to fit various window sizes, so it has excellent workability.

1A shows a bending test in which an electrochromic device according to an exemplary embodiment is bent and then straightened to its original shape.
1B illustrates a test in which an electrochromic element according to an exemplary embodiment is maintained in a bent state for a certain period of time.
1C illustrates a memory test in which power is cut off and maintained for a predetermined time in an electrochromic device according to an exemplary embodiment.
2 is a plan view and transmittance measurement points of a specimen for testing an electrochromic device according to an exemplary embodiment.
3 schematically illustrates a cross-section of an electrochromic device according to an exemplary embodiment.
4 schematically illustrates a cross-section of an electrochromic device and a light-transmitting variable structure according to an exemplary embodiment.
5 schematically illustrates a cross-section of an electrochromic device and a barrier layer according to an exemplary embodiment.
6 schematically illustrates a cross-section of an electrochromic device according to another embodiment.
7 is a perspective view conceptually illustrating a window to which an electrochromic element is applied according to an exemplary embodiment.
8 is a cross-sectional view taken along line AA' in FIG. 7 and an enlarged view thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention. However, the embodiment may be embodied in many different forms and is not limited to the embodiment described herein.

Where each film, window, panel, structure, or layer, etc. is described herein as being formed "on" or "under" each film, window, panel, structure, or layer, etc. As such, “on” and “under” include both “directly” or “indirectly” formed through another element.

In addition, the reference for the upper / lower of each component will be described with reference to the drawings. The size of each component in the drawings may be exaggerated for explanation, and does not mean a size actually applied. Also, like reference numerals refer to like elements throughout.

In the present specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

In the present specification, unless otherwise specified, the expression “a” is interpreted as meaning including “a” or “plural” as interpreted in context.

In addition, it should be understood that all numbers and expressions indicating amounts of components, reaction conditions, etc. described herein are modified by the term "about" in all cases unless otherwise specified.

In this specification, terms such as first, second, etc. are used to describe various components, and the components should not be limited by the terms. The above terms are used for the purpose of distinguishing one component from another component.

An electrochromic device according to an embodiment includes a first base layer, a second base layer, and a light-transmitting variable structure disposed therebetween.

The light-transmitting variable structure includes a first color-changing layer that can be colored and discolored according to the application of power.

In addition, the light-transmitting variable structure is a first electrode layer under the first color-changing layer; an electrolyte layer on the first color-changing layer; a second color-changing layer on the electrolyte layer; and a second electrode layer on the second color-changing layer, wherein the first color-changing layer includes a reducing color-changing material and a polymer resin, and the second color-changing layer includes an oxidative color-changing material and a polymer resin.

In the electrochromic device 100 according to a specific embodiment, the light transmission variable structure 130 is interposed between the first base layer 110 and the second base layer 150, and the light transmission variable structure 130 is It includes a first color-changing layer 133 and a second color-changing layer 137 , and an electrolyte layer 135 is interposed between the first color-changing layer 133 and the second color-changing layer 137 ( FIGS. 3 and 3 and see Fig. 4).

The electrochromic device 100 may be a flexible electrochromic device. In addition, the electrochromic element may have a sheet or film form.

The electrochromic device 100 may have a thickness of 20 μm to 1,000 μm. Specifically, the thickness of the electrochromic device 100 may be 25 μm to 900 μm, 25 μm to 800 μm, 25 μm to 700 μm, 25 μm to 600 μm, or 25 μm to 500 μm, but is limited thereto. it is not

The electrochromic device may have an average visible light transmittance of 40% to 90%, 50% to 90%, or 60% to 80% in the maximum decolorization state, but is not limited thereto. In addition, the electrochromic element may have an average visible light transmittance of 10% to 40%, 10% to 30%, or 10% to 20% in the maximum colored state, but is not limited thereto.

The electrochromic element may control transmittance of infrared (IR) and ultraviolet (UV) rays as well as visible light during coloring and decolorization.

Characteristics such as constituent components and physical properties of each layer of the above-described electrochromic element may be combined with each other.

Flexible properties of electrochromic elements

The electrochromic device according to the embodiment has a flexible characteristic while realizing an excellent light transmittance variable function based on the electrochromic principle. In particular, when the electrochromic device according to the embodiment is repeatedly bent or maintained in a bent state for a long time or when the power is cut off for a long time, there is little change in transmittance compared to the initial stage, and the transmittance operation function can be maintained as it is. For example, when the electrochromic element is bent in a tensile or compressive direction with respect to the first color-changing layer or the second color-changing layer, the color-changing function may be maintained.

Specifically, as shown in FIG. 1A , there may be little change in transmittance when the test of bending and unfolding both ends at a distance D corresponding to 25% of the transverse length L of the electrochromic device is repeated. In addition, as shown in FIG. 1B , there may be little change in transmittance even when both ends are bent at a distance D corresponding to 25% of the transverse length L of the electrochromic element and maintained for a long time. In addition, as shown in FIG. 1c , there may be little change in transmittance even when the power to the electrochromic device is cut off and maintained for a long time.

According to one embodiment, the electrochromic element is bent so that the distance between both ends in the horizontal direction is 75 mm based on the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length, and then unfolds to its original shape. When the bending test is repeated, the first transmittance change (ΔTT_B30) defined in Equation (1) below is within 1.5%.

△TT_B30 (%) = │TT_B30 - TT_0│ ... (1)

In Equation (1), TT_B30 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after repeating the bending test 30 times, and TT_0 is the electrical measured in the maximum discoloration state before the bending test. It is the average visible light transmittance (%) of the color-changing element.

More specifically, the first transmittance change ΔTT_B30 may be within 1%, within 0.5%, or within 0.3%.

In addition, the values of TT_B30 and TT_0 in Formula (1) may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, the values of TT_B30 and TT_0 in Equation (1) may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In addition, when the electrochromic device repeats the bending test, the second transmittance change (ΔTT_B30_d) defined in Equation (2) below may be within 3%.

△TT_B30_d (%) = ││TT_B30 - TT_B30'│-│TT_0 - TT_0'││ ... (2)

In Equation (2), TT_B30 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after repeating the bending test 30 times, and TT_B30' is the maximum coloring state after repeating the bending test 30 times. is the measured average visible light transmittance (%) of the electrochromic element, TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the bending test, and TT_0' is the maximum before the bending test It is the average visible light transmittance (%) of the electrochromic element measured in the colored state.

More specifically, the second transmittance change ΔTT_B30_d may be within 2%, within 1%, within 0.5%, or within 0.3%.

In addition, the values of TT_B30 and TT_0 in Equation (2) may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, the values of TT_B30 and TT_0 in Equation (2) may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In addition, the values of TT_B30' and TT_0' in Equation (2) may be 30% or less, 20% or less, or 15% or less, respectively, and may be 0% or more, 5% or more, or 10% or more, respectively. Specifically, the values of TT_B30' and TT_0' in Equation (2) may be 0% to 30%, 5% to 10%, or 10% to 15%, respectively.

In addition, when the electrochromic device repeats the bending test, the third transmittance change (ΔTT_B50) defined in Equation (3) below may be within 3%.

△TT_B50 (%) = │TT_B50 - TT_0│ ... (3)

In Equation (3), TT_B50 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after repeating the bending test 50 times, and TT_0 is the electrical measured in the maximum discoloration state before the bending test It is the average visible light transmittance (%) of the color-changing element.

More specifically, the third transmittance change ΔTT_B50 may be within 2%, within 1%, within 0.5%, or within 0.3%.

In addition, the values of TT_B50 and TT_0 in Equation (3) may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, the values of TT_B50 and TT_0 in Equation (3) may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In addition, in a test in which the electrochromic element is bent so that the distance between both ends in the horizontal direction is 75 mm based on the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length, for a certain period of time, The fourth transmittance change (ΔTT_100H) defined in Equation (4) below may be within 3%.

△TT_100H (%) = │TT_100H - TT_0│ ... (4)

In Equation (4), TT_100H is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after performing the sustain test for 100 hours, and TT_0 is the electrical measurement measured in the maximum discoloration state before the sustain test. It is the average visible light transmittance (%) of the color-changing element.

More specifically, the fourth transmittance change (ΔTT_100H) may be within 2%, within 1%, within 0.5%, or within 0.3%.

In addition, the values of TT_100H and TT_0 in Equation (4) may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, the values of TT_100H and TT_0 in Equation (4) may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In addition, when the electrochromic device repeats the bending test after performing the sustain test, the fifth transmittance change (ΔTT_100H_B30) defined in Equation (5) below may be within 3%.

△TT_100H_B30 (%) = │TT_100H_B30 - TT_0│ ... (5)

In Equation (5), TT_100H_B30 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after performing the sustain test for 100 hours and then repeating the bending test 30 times, TT_0 is the sustain test It is the average visible light transmittance (%) of the electrochromic element previously measured in the maximum discoloration state.

More specifically, the fifth transmittance change ΔTT_100H_B30 may be within 2%, within 1%, within 0.5%, or within 0.3%.

In addition, the values of TT_100H_B30 and TT_0 in Equation (5) may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, the values of TT_100H_B30 and TT_0 in Equation (5) may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

In addition, in the memory test in which the electrochromic element repeats the bending test, applies power to make the maximum discoloration state, then cuts off the power and maintains it for a certain period of time, the sixth transmittance defined in Equation (6) below The change (ΔTT_B30_M12H) may be within 3%.

△TT_B30_M12H (%) = │TT_B30_M12H - TT_0│ ... (6)

In Equation (6), TT_B30_M12H is the average visible light transmittance (%) of the electrochromic device measured after repeating the bending test 30 times and performing the memory test in the maximum discoloration state for 12 hours, TT_0 is before the bending test is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state.

More specifically, the sixth transmittance change (ΔTT_B30_M12H) may be within 2%, within 1%, within 0.5%, or within 0.3%.

In addition, the values of TT_B30_M12H and TT_0 in Formula (6) may be 50% or more, 60% or more, or 65% or more, respectively, and may be 90% or less, 80% or less, or 70% or less, respectively. Specifically, the values of TT_B30_M12H and TT_0 in Equation (6) may be 50% to 90%, 60% to 80%, or 65% to 70%, respectively.

The average visible light transmittance referred to in Equations (1) to (6), etc., means an average value of transmittance in the visible light wavelength range, specifically, the average value of transmittances measured at 5 nm intervals in a wavelength of 380 to 780 nm. there is.

base layer

The first base layer 110 and the second base layer 150 correspond to layers for maintaining transparency and durability, and may include a polymer resin. For example, the first base layer and the second base layer may be a polymer film.

Specifically, the first base layer and the second base layer each include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), and polycyclohexylenedimethylene terephthalate. (PCT), polyethersulfone (PES), nylon (nylon), polymethyl methacrylate (PMMA), and may include at least one selected from the group consisting of cycloolefin polymer (COP), but is not limited thereto. . More specifically, each of the first base layer and the second base layer may include polyethylene terephthalate (PET).

Since the first base layer and the second base layer include the above-described polymer resin, an electrochromic device having both durability and flexibility can be implemented.

The first base layer and the second base layer may each have a light transmittance of 80% or more with respect to light having a wavelength of 550 nm. Specifically, the first base layer and the second base layer may each have a light transmittance of 85% or more or 90% or more with respect to light having a wavelength of 550 nm. The first base layer and the second base layer may each have a haze of less than 2.0%, 1.8% or less, or 1.5% or less. The first base layer and the second base layer may each have an elongation of 80% or more. Specifically, the first base layer and the second base layer may each have an elongation of 90% or more, 100% or more, or 120% or more. The first base layer and the second base layer may exhibit transparency by satisfying the light transmittance and haze of the above-described ranges, respectively, and may exhibit flexibility by satisfying the elongation of the above-described ranges.

The thickness of the first base layer and the thickness of the second base layer may be 10 μm to 300 μm, respectively. Specifically, the thickness of the first base layer and the thickness of the second base layer are respectively 50 μm to 180 μm, 70 μm to 180 μm, 80 μm to 180 μm, 100 μm to 180 μm, 100 μm to 170 μm, Alternatively, it may be 100 μm to 150 μm, but is not limited thereto. When the thickness of the first base layer and the thickness of the second base layer satisfy the above ranges, the elongation and tensile strength of the electrochromic device can be implemented at a specific level. In addition, even when the electrochromic element is bent, cracks or cracks do not occur in each layer, and it is possible to implement a thin, light and flexible electrochromic element, which is advantageous for thin film formation.

barrier layer

The barrier layer serves to prevent penetration of impurities including moisture or gas into the light-transmitting variable structure from the outside, and may include, for example, a first barrier layer and a second barrier layer.

Each of the first barrier layer 120 and the second barrier layer 140 may include two or more layers. Specifically, each of the first barrier layer 120 and the second barrier layer 140 may include two layers or three layers (see FIG. 5 ).

For example, the first barrier layer 120 may include two layers, and the second barrier layer 140 may include two layers. Alternatively, the first barrier layer 120 may include three layers, and the second barrier layer 140 may include three layers.

In one embodiment, the first barrier layer 120 includes a 1A barrier layer 121 and a 1B barrier layer 122, or the first barrier layer includes a 1A barrier layer 121 and a 1B It may include a barrier layer 122 and a 1C barrier layer 123 (see FIG. 5 ).

Specifically, the first barrier layer may include a structure in which a 1A barrier layer and a 1B barrier layer are sequentially stacked; Alternatively, the 1A barrier layer, the 1B barrier layer, and the 1C barrier layer may be sequentially stacked.

The first barrier layer may be laminated on the first base layer.

In one embodiment, the second barrier layer 140 includes a 2A barrier layer 141 and a 2B barrier layer 142, or the second barrier layer includes a 2A barrier layer 141 and a 2B second barrier layer. It may include a barrier layer 142 and a 2C barrier layer 143 (see FIG. 5 ).

Specifically, the second barrier layer may include a structure in which a 2A barrier layer and a 2B barrier layer are sequentially stacked; Alternatively, the 2A barrier layer, the 2B barrier layer, and the 2C barrier layer may be sequentially stacked.

The second barrier layer may be laminated on a lower surface of the second base layer.

In one embodiment, the first barrier layer 120 includes a 1A barrier layer 121 and a 1B barrier layer 122 , and the second barrier layer 140 is a 2A barrier layer 141 . and a 2B barrier layer 142 . Alternatively, the first barrier layer includes a 1A barrier layer 121 , a 1B barrier layer 122 , and a 1C barrier layer 123 , and the second barrier layer 140 is a 2A barrier layer 141 . ) and a 2B barrier layer 142 .

The first barrier layer 120 and the second barrier layer 140 are each selected from the group consisting of a metal oxide, a metal nitride, a metal oxynitride, a metalloid oxide, a metalloid nitride, a metalloid oxynitride, and combinations thereof. contains one or more species.

Specifically, each of the first barrier layer 120 and the second barrier layer 140 includes at least one selected from the group consisting of a metal nitride, a metal oxynitride, a metalloid nitride, a metalloid oxynitride, and combinations thereof. include

More specifically, each of the first barrier layer 120 and the second barrier layer 140 includes a metal nitride or a metalloid nitride.

In an embodiment, the first barrier layer 120 includes a 1A barrier layer 121 and a 1B barrier layer 122, and one of the 1A barrier layer and the 1B barrier layer is a metal oxide. Alternatively, it may include a metalloid oxide, and the other one may include a metal nitride or a metalloid nitride.

The first barrier layer 120 may further include a 1C barrier layer 123 . In this case, the 1C barrier layer may include an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or a polyurethane resin.

In addition, the second barrier layer 140 includes a 2A barrier layer 141 and a 2B barrier layer 142 , and one of the 2A barrier layer and the 2B barrier layer is a metal oxide or a metalloid oxide. and the other one may include a metal nitride or a metalloid nitride.

The second barrier layer 140 may further include a 2C barrier layer 143 . In this case, the 2C barrier layer may include an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or a polyurethane resin.

In another embodiment, the first barrier layer includes a first A barrier layer and a first B barrier layer, and a thickness ratio of the first A barrier layer and the first B barrier layer is 1:2 to 1:10. In this case, the first A barrier layer includes a metal nitride or a metalloid nitride, and the first B barrier layer includes a metal oxide or a metalloid oxide.

A thickness ratio of the barrier layer 1A and the barrier layer 1B may be 1:2.5 to 1:10 or 1:2.5 to 1:7.5, but is not limited thereto.

In addition, the second barrier layer may include a second A barrier layer and a second B barrier layer, and a thickness ratio of the second A barrier layer and the second B barrier layer may be 1:2 to 1:10. In this case, the 2A barrier layer includes a metal nitride or a metalloid nitride, and the 2B barrier layer includes a metal oxide or a metalloid oxide.

The thickness ratio of the 2A barrier layer and the 2B barrier layer may be 1:2.5 to 1:10 or 1:2.5 to 1:7.5, but is not limited thereto.

The thickness ratio of the 1A barrier layer and the 1B barrier layer and the thickness ratio of the 2A barrier layer and the 2B barrier layer satisfy the above range, thereby improving long-term reliability such as optical properties, refractive index and weather resistance of the film It works.

On the other hand, when the thickness ratio of the 1A barrier layer and the 1B barrier layer or the thickness ratio of the 2A barrier layer and the 2B barrier layer is out of the above range, the refractive index decreases, becomes opaque, optical properties and weather resistance There is a problem that long-term reliability is lowered, such as

In one embodiment, the first barrier layer includes a 1A barrier layer and a 1B barrier layer, a first base layer, a 1A barrier layer, and a 1B barrier layer are sequentially stacked, and the 1A barrier layer Silver includes a metal nitride or a metalloid nitride, and the 1B barrier layer includes a metal oxide or a metalloid oxide.

In another embodiment, the first barrier layer includes a 1A barrier layer, a 1B barrier layer and a 1C barrier layer, and the first substrate layer, the 1A barrier layer, the 1B barrier layer and the 1C barrier layer are stacked sequentially, wherein the 1A barrier layer includes a metal nitride or a metalloid nitride, the 1B barrier layer includes a metal oxide or a metalloid oxide, and the 1C barrier layer includes an acrylic resin, an epoxy resin, silicone-based resins, polyimide-based resins, or polyurethane-based resins.

In this case, the thickness of the barrier layer 1A may be 10 nm to 50 nm, 10 nm to 40 nm, or 10 nm to 30 nm, but is not limited thereto.

In addition, the thickness of the barrier layer 1B may be 30 nm to 100 nm, 30 nm to 80 nm, 30 nm to 70 nm, or 40 nm to 60 nm, but is not limited thereto.

Each of the barrier layer 1A and the barrier layer 1B may have a moisture permeability of 0.2 g/day·m ² or less, 0.15 g/day·m ² or less, or 0.1 g/day·m ² or less, but is not limited thereto. .

The 1A barrier layer When the thickness range and the water vapor transmission rate of the 1B barrier layer satisfy the above ranges, long-term reliability such as optical properties, refractive index, and weather resistance of the film is improved.

On the other hand, when it is out of the above range, there is a problem in that the refractive index is lowered, the refractive index becomes opaque, or the long-term reliability such as optical properties and weather resistance is lowered.

In one embodiment, the second barrier layer includes a 2A barrier layer and a 2B barrier layer, a second base layer, a 2A barrier layer, and a 2B barrier layer are sequentially stacked, and the 2A barrier layer Silver includes a metal nitride or a metalloid nitride, and the 2B barrier layer includes a metal oxide or a metalloid oxide.

In addition, the second barrier layer includes a 2A barrier layer, a 2B barrier layer and a 2C barrier layer, and a second substrate layer, a 2A barrier layer, a 2B barrier layer and a 2C barrier layer are sequentially stacked. , The 2A barrier layer includes a metal nitride or a metalloid nitride, the 2B barrier layer includes a metal oxide or a metalloid oxide, and the 2C barrier layer is an acrylic resin, an epoxy resin, a silicone resin, or a polyimide. It contains a mid-type resin or a polyurethane-type resin.

In this case, the thickness of the barrier layer 2A may be 10 nm to 50 nm, 10 nm to 40 nm, or 10 nm to 30 nm, but is not limited thereto.

In addition, the thickness of the barrier layer 2B may be 30 nm to 100 nm, 30 nm to 80 nm, 30 nm to 70 nm, or 40 nm to 60 nm, but is not limited thereto.

The 2A barrier layer and the 2B barrier layer may have a moisture permeability of 0.2 g/day·m ² or less, 0.15 g/day·m ² or less, or 0.1 g/day·m ² or less, respectively, but is not limited thereto. .

The 1A barrier layer The thickness range and the water vapor transmission rate of the 1B barrier layer satisfy the above ranges, thereby improving long-term reliability such as optical properties, refractive index and weather resistance of the film. On the other hand, when out of the above range, the refractive index This deterioration, opacity, or long-term reliability, such as optical properties and weather resistance, there is a problem.

The moisture permeability of the first barrier layer and the second barrier layer may be the same or different. Specifically, the moisture permeability of the first barrier layer and the second barrier layer may be different.

As a specific embodiment, the first barrier layer includes a 1A barrier layer and a 1B barrier layer, a first base layer, a 1A barrier layer, and a 1B barrier layer are sequentially stacked, and the 1A barrier layer Silver includes silicon nitride (SiNx), and the 1B barrier layer includes silicon oxide (SiOx). In addition, optionally, the first barrier layer may further include a 1C barrier layer including an acrylic resin.

When the 1A barrier layer includes silicon nitride, the Si:N ratio may be 1.0:0.8 to 1.0:1.2, but is not limited thereto. When the 1B barrier layer includes silicon oxide, the Si:O ratio may be 1.0:1.7 to 1.0:2.3, but is not limited thereto.

In addition, the second barrier layer includes a 2A barrier layer and a 2B barrier layer, a second substrate layer, a 2A barrier layer, and a 2B barrier layer are sequentially stacked, and the 2A barrier layer is silicon nitride ( SiNx), and the 2B barrier layer includes silicon oxide (SiOx). In addition, optionally, the second barrier layer may further include a 2C barrier layer including an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or a polyurethane resin.

When the 2A barrier layer includes silicon nitride, the Si:N ratio may be 1.0:0.8 to 1.0:1.2, but is not limited thereto. When the 2B barrier layer includes silicon oxide, the Si:O ratio may be 1.0:1.7 to 1.0:2.3, but is not limited thereto.

Since the first barrier layer and the second barrier layer satisfy the above-mentioned conditions, desired performance can be realized even with a thin thickness, and durability and long-term stability of the electrochromic device can be improved by maximally preventing moisture penetration.

The first barrier layer and the second barrier layer may be deposited on each of the first base layer and the second base layer by a vacuum deposition method. Specifically, the first barrier layer and the second barrier layer may be deposited on each of the first base layer and the second base layer by a sputtering deposition method.

In this case, the deposition raw material may be at least one of a metal or a metalloid, and the type is not particularly limited, but, for example, magnesium (Mg), silicon (Si), indium (In), titanium ( Ti), bismuth (Bi), germanium (Ge), and may include at least one selected from aluminum (Al).

The deposition reaction gas may include an oxygen (O ₂ ) gas or a nitrogen (N ₂ ) gas. When oxygen gas is used as a reactive gas, a barrier layer including a metal oxide or a metalloid oxide is formed, and when nitrogen gas is used as a reaction gas, a barrier layer including a metal nitride or a metalloid nitride can be formed. When an oxygen gas and a nitrogen gas are appropriately mixed and used as the reaction gas, a barrier layer including a metal oxynitride or a metalloid oxynitride may be formed.

The vacuum deposition method includes a physical vacuum deposition method and a chemical vacuum deposition method. The physical vacuum deposition method includes thermal vacuum deposition, E-beam vacuum deposition, and sputtering deposition.

The sputtering may be DC magnetron sputtering or AC magnetron sputtering.

The DC magnetron sputtering may be specifically, plasma sputtering, for example, reactive plasma sputtering.

light transmittance variable structure

The light-transmitting variable structure 130 includes a first electrode layer 131; a first color-changing layer 133 on the first electrode layer 131; an electrolyte layer 135 on the first discoloration layer 133; a second discoloration layer 137 on the electrolyte layer 135; and a second electrode layer 139 on the second discoloration layer 137 (see FIG. 4 ).

The light-transmitting variable structure 130 is a structure in which a first electrode layer 131 , a first color-changing layer 133 , an electrolyte layer 135 , a second color-changing layer 137 and a second electrode layer 139 are sequentially stacked. can be Specifically, the light transmittance variable structure is a laminate structure in which light transmittance is reversibly changed when a predetermined voltage is applied.

Specifically, when a voltage is applied to the first electrode layer 131 and the second electrode layer 139 , from the second color-changing layer 137 through the electrolyte layer 135 to the first color-changing layer 133 . The overall light transmittance increases and decreases due to specific ions or electrons moving through them.

When the light transmittance of the second color-changing layer 137 is lowered, the light transmittance of the first color-changing layer 133 is also lowered, and when the light transmittance of the second color-changing layer 137 is increased, the first color change The light transmittance of the layer 133 is also increased.

first electrode layer and second electrode layer

Each of the first electrode layer and the second electrode layer may include a transparent electrode or a reflective electrode. In one embodiment, one of the first electrode layer and the second electrode layer may be a transparent electrode, and the other may be a reflective electrode. In another embodiment, both the first electrode layer and the second electrode layer may be transparent electrodes.

The first electrode layer 131 may be formed by depositing on the first barrier layer 120 by a sputtering method. In addition, the second electrode layer 139 may be formed by depositing on the second barrier layer 140 by a sputtering method.

The transparent electrode may be made of a material having high transmittance to light, low sheet resistance, and penetration resistance, and may be configured in the shape of an electrode plate.

The transparent electrode is, for example, from the group consisting of indium-tin oxide (ITO, indium-tin oxide), zinc oxide (ZnO, zinc oxide), indium-zinc oxide (IZO, indium-zinc oxide), and combinations thereof. It may include a selected one.

The reflective electrode is, for example, a group consisting of silver (Ag), aluminum (Al), copper (Cu), molybdenum (Mo), gold (Au), tungsten (W), chromium (Cr), and combinations thereof. It may include at least one selected from

Each of the first electrode layer 131 and the second electrode layer 139 may have a thickness of 100 nm to 500 nm, 100 nm to 400 nm, 100 nm to 300 nm, or 150 nm to 250 nm, but is limited thereto. it is not

Each of the first electrode layer and the second electrode layer may be a transparent electrode, and may include indium-tin oxide.

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

In addition, the surface resistance of each of the first electrode layer and the second electrode layer is 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 It may be 50 Ω/sq, but is not limited thereto.

first chromic layer

The first color-changing layer 133 is a layer in which light transmittance changes when a voltage is applied between the first electrode layer 131 and the second electrode layer 139, and is a layer that imparts light transmittance variability to the electrochromic device. am.

The first color-changing layer 133 may include a material having a color development characteristic complementary to the electrochromic material included in the second color-changing layer 137 . The complementary color development characteristic means that the types of reactions in which the electrochromic material develops colors are different from each other.

For example, when an oxidative color-changing material is used for the first color-changing layer, a reducing color-changing material may be used for the second color-changing layer, and when a reducing color-changing material is used for the first color-changing layer, the second color-changing material An oxidative color change material may be used for the layer.

Specifically, the first color-changing layer 133 may include a reducing color-changing material, and the second color-changing layer 137 may include an oxidative color-changing material.

The oxidative color-changing material refers to a material that changes color when an oxidation reaction occurs, and the reductive color-change material refers to a material that changes color when a reduction reaction occurs.

That is, when an oxidation reaction occurs in the color-changing layer to which an oxidative color-changing material is applied, a coloring reaction occurs, and when a reduction reaction occurs, a decolorization reaction occurs. When a reduction reaction occurs in the color-changing layer to which a reducing color-changing material is applied, a coloring reaction occurs, and when an oxidation reaction occurs, a decolorization reaction occurs.

Since the material having such complementary color development properties is included in each color-changing layer, coloring or color development can be performed simultaneously in both layers. In addition, coloring or color development may be alternated according to the polarity of a voltage applied to the electrochromic element.

The initial transmittance of the first electrode layer 131 and the first color-changing layer 133 may be 90% or more. Specifically, if the initial transmittance satisfies the above range, it means that each of the above-described layers is applied very uniformly, respectively, and indicates that the layer is very transparent.

In one embodiment, the first color-changing layer 133 may include a reducing color-changing material and a polymer resin.

The reducible color-changing material is titanium oxide (TiO), vanadium oxide (V ₂ O ₅ ), niobium pentoxide (Nb ₂ O ₅ ), chromium oxide (Cr ₂ O ₃ ), manganese oxide (MnO ₂ ), iron oxide (FeO) ₂ ), cobalt oxide (CoO ₂ ), nickel oxide (NiO ₂ ), rhodium oxide (RhO ₂ ), tantalum oxide (Ta ₂ O ₅ ), iridium oxide (IrO ₂ ), tungsten oxide (WO _{2 ,} WO ₃ , W) ₂ O ₃ , W ₂ O ₅ ), viologen, and may be at least one selected from the group consisting of combinations thereof, but is not limited thereto.

The polymer resin may be a resin having flexibility, and specific types are not limited. For example, the polymer resin may be at least one selected from the group consisting of a silicone-based resin, an acrylic resin, a phenol-based resin, a polyurethane-based resin, a polyimide-based resin, and an ethylene vinyl acetate-based resin, but is not limited thereto. For example, the first color-changing layer 133 may include tungsten oxide (WO ₃ ) and an acrylic resin.

The first color-changing layer 133 may include a reducing color-changing material and a polymer resin, and may contain 0.1 to 15 parts by weight of the polymer resin based on 100 parts by weight of the reducible color-changing material. Specifically, the polymer resin may be included in an amount of 1 part by weight to 15 parts by weight, 2 parts by weight to 15 parts by weight, or 3 parts by weight to 10 parts by weight based on 100 parts by weight of the reducible color-changing material. Specifically, the first color-changing layer may include 100 parts by weight of the reducing color-changing material and 3 to 7 parts by weight of the polymer resin. When it is within the preferred range, it may be more advantageous to suppress a change in visible light transmittance that may occur after repeated bending of the electrochromic element, after maintaining the bent state for a long time, or after turning off the power for a long time.

On the other hand, when the first color-changing layer contains the polymer resin in excess of the above-mentioned range based on 100 parts by weight of the reducible color-changing material, memory performance is deteriorated, so that it is not possible to maintain a certain level of transmittance or it takes a long time to reach a specific transmittance. As the discoloration time increases, the discoloration rate may decrease. In addition, when the first color-changing layer contains less than the above-described range of the polymer resin based on 100 parts by weight of the reducible color-changing material, cracks may occur when deformed to a small radius of curvature due to a decrease in flexibility, and a certain level of It may be difficult to implement the variable light transmission function.

The first color-changing layer 133 may include at least one layer, for example, may include two or more layers of different materials.

The first color-changing layer 133 may have a thickness of 100 nm to 1,000 nm, 200 nm to 1,000 nm, 200 nm to 800 nm, 200 nm to 700 nm, or 300 nm to 700 nm, or 300 nm to 600 nm. there is. When the thickness of the first color-changing layer satisfies the above range, the degree of change in the light transmittance of the light-transmitting variable structure may impart significant light transmittance variability to the entire electrochromic element, whereby the entire electrochromic element may be a building or It can be applied to automobile windows, etc. to realize the light transmission change characteristic that can realize the energy control effect. In particular, when the thickness of the first color-changing layer is 300 nm to 600 nm, a change in visible light transmittance that may occur after repeated bending of the electrochromic element, after maintaining the bent state for a long time, or after turning off the power for a long time may be more advantageous in suppressing

In addition, a certain relationship may be satisfied between the thickness of the first discoloration layer and the content of the polymer resin. As a specific example, the first color-changing layer may have a thickness within ±150 nm, within ±100 nm, or within ±50 nm based on the thickness calculated in the formula below using the content of the polymer resin as a factor.

First color-changing layer thickness (nm) = [Polymer resin content (parts by weight) × 75 (nm/parts by weight)] + 75 (nm)

In the above formula, the content of the polymer resin is parts by weight of the polymer resin based on 100 parts by weight of the reducible color-changing material in the first color-changing layer.

When the desired relationship between the thickness of the first color-changing layer and the content of the polymer resin is satisfied, it may occur after repeated bending of the electrochromic element, after maintaining the bent state for a long time, or after turning off the power for a long time. It may be more advantageous to suppress a change in visible light transmittance.

second color change layer

The second color-changing layer 137 is a layer in which light transmittance is changed when a voltage is applied between the first electrode layer 131 and the second electrode layer 139, and is a layer that imparts light transmittance variability to the electrochromic device. am.

In an embodiment, the second color-changing layer 137 may include an oxidative color-changing material and a polymer resin.

The oxidative color change material is nickel oxide (eg, NiO, NiO ₂ ), manganese oxide (eg, MnO ₂ ), cobalt oxide (eg, CoO ₂ ), iridium -It may be at least one selected from the group consisting of iridium-magnesium oxide, nickel-magnesium oxide, titanium-vanadium oxide, Prussian blue pigment, and combinations thereof. However, the present invention is not limited thereto. The Prussian blue pigment is a dark blue pigment, and is a compound having a chemical formula of Fe ₄ (Fe(CN) ₆ ) ₃ .

The polymer resin may be a resin having flexibility, and specific types are not limited. For example, the polymer resin may be a urethane acrylic resin, a silicone resin, an acrylic resin, an ester resin, an epoxy resin, a phenol resin, a polyurethane resin, a polyimide resin, an ethylene vinyl acetate resin, etc., but limited thereto. it is not going to be

In addition, the weight average molecular weight of the polymer resin may be 50 to 10,000. Specifically, the weight average molecular weight of the polymer resin may be 100 to 10,000, 200 to 10,000, or 500 to 10,000, but is not limited thereto.

For example, the second color-changing layer 137 may include nickel oxide (NiO) and an acrylic resin, and the acrylic resin may have a weight average molecular weight of 50 to 10,000.

The second color-changing layer 137 may include an oxidative color-changing material and a polymer resin, and may contain 0.1 to 5 parts by weight of a polymer resin based on 100 parts by weight of the oxidative color-changing material.

When the second color-changing layer contains the above-described range of the polymer resin based on 100 parts by weight of the oxidative color-changing material, the oxidative color-changing material is stably attached to the film surface, thereby helping to implement smooth light transmission variable performance.

On the other hand, if the polymer resin is less than the above-mentioned range, the oxidative discoloration material may have weak adhesion to the film surface, which may cause a problem of detachment or scattering even with a slight external impact, and may cause color cracks during bending due to poor flexibility. In addition, when the polymer resin exceeds the above range, the ionic conductivity of the oxidative discoloration material may be lowered due to the resistance of the polymer resin itself, and the ionic conductivity performance of the oxidative discoloration material may be lowered, and the durability at high temperature may be weakened, thereby reducing the reliability. .

The second discoloration layer 137 includes at least one layer, and if necessary, two or more layers of different materials may be applied.

The thickness of the second color-changing layer 137 may 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 satisfies the above range, it can withstand external impact well and retain an appropriate amount of ions. It is advantageous to implement transmission change characteristics.

On the other hand, when the thickness of the second color-changing layer is less than the above range, it may be difficult to properly implement the color-changing performance due to a decrease in ionic conductivity because the color-changing layer is thin. In addition, when it exceeds the above range, the color-changing layer is thick and cracks may occur even with a slight external impact, which may make it difficult to implement as a flexible electrochromic device, and may be uneconomical due to increased manufacturing cost.

The initial transmittance of the second color-changing layer 137 may be 50% or less. Specifically, when the initial transmittance satisfies the above range, it means that it is dark and dark blue or pale indigo blue when viewed with the naked eye.

In an embodiment, the first color-changing layer 133 includes a reducing color-changing material, the second color-changing layer 137 includes an oxidative color-changing material, and the first color-changing layer and the second color-changing layer each include It may be formed by a wet coating method.

Specifically, the first discoloration layer 133 may be formed by coating a raw material on one surface of the first electrode layer 131 by a wet coating method and then drying it. In addition, the second discoloration layer 137 may be formed by applying a raw material to one surface of the second electrode layer 139 by a wet coating method and then drying it.

The solvent used in the wet coating may be a non-aromatic solvent or an aromatic solvent, and specifically, may be ethanol, acetone, toluene, or the like, but is not limited thereto.

When the first color-changing layer and the second color-changing layer are formed by the sputtering coating method, an electrochromic device having both excellent light transmittance variable performance and flexibility because only a very thin coating film of 100 nm or less can be formed due to the characteristics of the coating method There are limits to its application.

A thickness ratio of the first color-changing layer and the second color-changing layer may be 50:50 to 80:20, 55:45 to 75:25, or 60:40 to 70:30.

When the thickness ratio of the first color-changing layer and the second color-changing layer satisfies the above range, a color change period that becomes transparent and dark becomes wider and the color change time is shortened. On the other hand, when the above range is not satisfied, a color change section that becomes transparent and dark may be narrowed, and the color change time is increased to change slowly or it may be difficult to operate even when electricity is applied to the electrochromic device.

electrolyte layer

The electrolyte layer 135 is a layer serving as an ion movement path between the first color-changing layer and the second color-changing layer, and the type of electrolyte used in the electrolyte layer is not particularly limited.

For example, the electrolyte layer may include hydrogen ions or Group 1 element ions. Specifically, the electrolyte layer may include a lithium salt compound. The lithium salt compound may be LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiTFSi, LiFSi, or the like, but is not limited thereto.

In addition, the electrolyte layer may include a polymer resin. Specifically, the electrolyte layer may include an acrylic resin, an epoxy resin, a silicone resin, a polyimide resin, or a polyurethane resin, but is not limited thereto.

Specifically, the acrylic resin may be a thermosetting acrylic resin or a photocurable acrylic resin, and the polyurethane-based resin may be a thermosetting polyurethane-based resin, a photocurable polyurethane-based resin, or an aqueous polyurethane-based resin.

The electrolyte layer may include a polymer resin and a lithium salt in a weight ratio of 95:5 to 80:20, 95:5 to 85:15, or 93:7 to 87:3.

The ionic conductivity of the electrolyte layer is 10 ^-3 mS/cm or more. Specifically, the ionic conductivity of the electrolyte layer may be 10 ^-3 mS/cm to 10 ³ mS/cm, or 10 ^-3 mS/cm to 10 ² mS/cm, but is not limited thereto. When the ionic conductivity of the electrolyte layer is within the above range, a desired light transmittance variable performance can be realized, and it is advantageous in terms of flexibility and reliability at high temperature. On the other hand, when the ionic conductivity of the electrolyte layer is out of the above range, the color change rate is very slow, and thus the performance of the electrochromic device is deteriorated.

The adhesive strength of the electrolyte layer is 200 g/inch or more. Specifically, the adhesive force of the electrolyte layer may be 200 g/inch to 900 g/inch or 200 g/inch to 700 g/inch, but is not limited thereto. When the adhesive force of the electrolyte layer is within the above range, it is well adhered to both substrates to allow the performance of the electrochromic device to be smoothly expressed. On the other hand, when the adhesive force of the electrolyte layer is out of the above range, there is a problem in adhesion to both substrates, so that it is easily peeled off even by a small external shock or stimulus, or a discontinuous surface such as floating in an empty space or some layer surface is generated, and the ionic conductivity is lowered and it becomes difficult to realize the performance up to a certain level of the electrochromic device.

The electrolyte layer 135 may be formed by coating a raw material on one surface of any one of the first color-changing layer 133 or the second color-changing layer 137 by a wet coating method and then drying. .

When the electrolyte layer is applied by a wet coating method, the thickness of the coating film can be thickened or the thickness of the coating film can be easily controlled, which is advantageous in terms of improvement of ionic conductivity or improvement of discoloration rate. On the other hand, when using the sputtering coating method rather than the wet coating method for the electrolyte layer, there is a problem in that the coating film is easily broken due to the formation of a thin film of the coating film, or the ionic conductivity is lowered even if there is no damage.

The electrolyte layer 135 may have a thickness of 30 μm to 200 μm, 50 μm to 200 μm, 50 μm to 150 μm, 70 μm to 130 μm, or 80 μm to 120 μm. When the thickness of the electrolyte layer 135 satisfies the above range, durability is imparted to the electrochromic element and, at the same time, an ion movement path between the first color-changing layer and the second color-changing layer is secured to an appropriate length to achieve an appropriate speed. It is possible to implement the light transmission change performance.

release film layer

The electrochromic device 100 according to an embodiment may further include a release film layer 160 on a surface opposite to the surface on which the first barrier layer 120 of the first base layer 110 is laminated. (See Fig. 6).

The release film layer 160 may include a polyester-based resin including polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polycarbonate (PC).

Specifically, the thickness of the release film layer may 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 thereto.

The peeling force of the release film layer is 50 gf/inch or less. Specifically, the peeling force of the release film layer may be 3 gf/inch to 50 gf/inch, or 10 gf/inch to 50 gf/inch, but is not limited thereto.

The release film layer serves to protect the electrochromic element from external moisture or impurities during storage and movement of the electrochromic element. It can also be used later. The release film layer can prevent a decrease in the adhesion of the pressure-sensitive adhesive layer in particular.

An adhesive layer 161 may be formed on one surface of the release film layer.

The pressure-sensitive adhesive layer 161 may include an acrylic resin, a silicone-based resin, a polyurethane-based resin, an epoxy-based resin, or a polyimide-based resin. Specifically, the pressure-sensitive adhesive layer may include an acrylic resin, and in this case, it is advantageous to improve optical properties and durability.

The UV blocking rate (based on 400 nm) of the pressure-sensitive adhesive layer may be 95% or more, 97% or more, 98% or more, or 99% or more, but is not limited thereto.

In addition, the initial adhesive force of the pressure-sensitive adhesive layer may be 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.

primer layer

A primer layer may be laminated on one or both surfaces of the first base layer 110 . Specifically, the 1A primer layer 111 may be laminated on one surface of the first base layer 110 , and the 1B primer layer 112 may be laminated on the other surface (see FIG. 6 ).

In addition, a primer layer may be laminated on one or both surfaces of the second base layer 150 . Specifically, a 2A primer layer 151 may be laminated on one surface of the second base layer 150 , and a 2B primer layer 152 may be laminated on the other surface (see FIG. 6 ).

In one embodiment, a primer layer may be interposed between the first barrier layer 120 and the first base layer 110 . In addition, a primer layer may be interposed between the second barrier layer 140 and the second base layer 150 (see FIG. 6 ).

Each of the primer layers (1A primer layer, 1B primer layer, 2A primer layer, and 2B primer layer) may include an acrylic resin, a polyurethane-based resin, a silicone-based resin, or a polyimide-based resin.

Each of the primer layers (1A primer layer, 1B primer layer, 2A primer layer, and 2B primer layer) may have a surface tension of 35 dyne/cm ² or less, or a surface tension of 30 dyne/cm ² or less. .

The primer layer (1A primer layer, 1B primer layer, 2A primer layer, 2B primer layer) may have an adhesive force of 3.0 gf/inch or more or 3.5 gf/inch or more.

The primer layer serves to impart adhesion between the base layer and the barrier layer or to improve the refractive index. In addition, the material for forming each of the primer layers, surface tension, peeling force, etc. may be the same or different.

hard coating layer

The electrochromic device 100 according to an embodiment may further include a hard coating layer 170 on the opposite side of the surface on which the second barrier layer 140 of the second base layer 150 is laminated ( 6).

The hard coating layer 170 may include an acrylic resin, a silicone-based resin, a polyurethane-based resin, an epoxy-based resin, or a polyimide-based resin.

The thickness of the hard coating layer may 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 thereto.

The pencil hardness of the hard coating layer may be 3H or more, 4H or more, or 5H or more, but is not limited thereto.

The hard coating layer serves to protect the electrochromic element from external impact, and can provide excellent hardness because it is strong against scratches and the like.

In addition, since the thickness of the hard coating layer satisfies the above range, an electrochromic device having flexibility and excellent workability can be implemented. may be vulnerable to the impact of

In a specific embodiment, the electrochromic device 100 includes a release film layer 160; a pressure-sensitive adhesive layer 161 on the release film layer 160; 1B primer layer 112 on the pressure-sensitive adhesive layer 161; a first base layer 110 on the 1B primer layer 112; 1A primer layer 111 on the first base layer 110; a first barrier layer 120 on the 1A primer layer 111; a light transmission variable structure 130 on the first barrier layer 120; a second barrier layer 140 on the light-transmitting variable structure 130 ; a 2A primer layer 151 on the second barrier layer 140; a second base layer 150 on the 2A primer layer 151; a 2B primer layer 152 on the second base layer 150; and a hard coating layer 170 on the second primer layer 152 .

Effects and uses

Since the electrochromic device has a characteristic of reversibly changing the light transmittance when power is applied, it is possible to selectively control the transmittance of sunlight, etc. only by a simple operation such as pressing a button, thereby increasing energy efficiency. In particular, when power is applied to the electrochromic device, an electric field is formed between the two electrodes to cause coloring and discoloration, so that transmittance can be adjusted for each wavelength of sunlight, which is useful because it is possible to implement a thermal insulation function and a shading function. In addition, the electrochromic device can manufacture a device of a large area at a low cost and has low power consumption, so it is suitable for use as a material for smart windows, smart mirrors, and other next-generation architectural windows. In addition, the electrochromic device has a thin thickness and light and flexible characteristics, so it has excellent workability, a low risk of breakage, can be stored in a roll form, and is easy to transport.

The electrochromic element realizes a variable light transmission function and at the same time has flexibility, thereby overcoming the limitation that had to be applied only to a rigid structure in the prior art, and simply attaching it to a structure such as an existing transparent window. can be obtained For example, the electrochromic device can be applied by simply attaching it to a structure such as an existing transparent window. Specifically, it can be attached to one side of the window as shown in FIG. More specifically, a cross-sectional view taken along line A-A' of FIG. 7 and an enlarged view of a portion to which an electrochromic element is applied are shown in FIG. 8 . The electrochromic device 100 may be attached to one surface of the window 10 , and the window 10 may have a flat surface or a curved surface. In addition, the electrochromic device 100 may be attached to the front surface of the window 10 or may be attached to only a portion of the window 10 . In addition, the electrochromic device 100 may be inserted into the window 10 . Specifically, it can be applied by interposing the electrochromic element between the glass substrate and the glass substrate. More specifically, it can be applied by interposing two PVB films (polyvinyl butyral film) between the laminated glass and the laminated glass of the window, and interposing an electrochromic element between the two PVB films, and pressing through heat to the window It can be stably inserted inside.

[Example]

Although specific embodiments will be described below, it should be understood that various forms including equivalents and substitutes corresponding to the technical scope of these embodiments can be implemented.

Example 1

Step 1: Preparation of acrylic resin

Prepare a 1L three-necked round flask (flask A) equipped with a thermometer, condenser, dropping funnel, and mechanical stirrer, and after adding 300 g of ethyl acetate and 1.5 g of azobisisobutyronitrile (AIBN) as a radical polymerization initiator, 80 Rotational stirring was performed at 100 times per minute using a mechanical stirrer in a constant temperature bath at °C. At this time, the temperature of the cooler was maintained at 10 ℃. In another flask (Flask B), 189 g of butyl acrylate, 27 g of methyl methacrylate, 51 g of 2-hydroxyethyl acrylate and 30 g of para-dodecyl styrene were added and mixed with a mechanical stirrer for 30 minutes, It was slowly introduced into the flask (Flask A) using a dropping funnel, and the polymerization reaction was carried out while maintaining the temperature at 80°C. When the desired weight average molecular weight was reached, the reaction was terminated by cooling slowly at room temperature to obtain an acrylic resin. As a result of gel permeation chromatography (GPC), the weight average molecular weight was 70,000 g/mol, and the dispersion was 4.2.

Step 2: Preparation of electrochromic device

Two transparent electrode substrates having a primer layer, a barrier layer, and an ITO electrode layer (surface resistance 50 Ω/s) formed on a PET substrate layer (thickness 125 μm) were prepared, and these were used as upper and lower plates.

Dissolve the acrylic resin (prepared in step 1) in toluene and mix it with an aqueous ammonium metatungstate solution to prepare a tungsten oxide (WO ₃ ) paste, but 3 parts by weight of the acrylic resin relative to 100 parts by weight of tungsten oxide (WO ₃ ) prepared. A tungsten oxide paste was wet-coated on the ITO electrode layer of the lower plate and dried at 140° C. for 5 minutes to form a reduced color change layer (thickness 300 nm).

In addition, a Prussian blue pigment was wet-coated on the ITO electrode layer of the upper plate and dried at 140° C. for 5 minutes to form an oxidative discoloration layer (thickness 400 nm).

An electrochromic device (width 300 mm × length 200 mm) was prepared by coating and laminating a gel electrolyte (ion conductivity of 50 μS/cm or more) to a thickness of 100 μm between the reduction color change layer and the oxidation color change layer. Then, copper tapes were attached to the side surfaces of the ITO electrode layers of the upper and lower plates to form a bus bar capable of power connection.

Examples 2 to 9 and Comparative Examples 1 and 2

As shown in Tables 1 to 4, an electrochromic device was prepared in the same manner as in Example 1, except that the weight ratio of tungsten oxide and the acrylic resin and/or the thickness of the reduced color-change layer were changed as the composition of the reduced color-changing layer. .

test example

The following tests were performed on the electrochromic devices manufactured in Examples and Comparative Examples.

go. Specimen size: 300 mm wide × 200 mm long × 350 μm thick

me. Test Methods

- Bending test: After bending the specimen so that the distance between both ends of the specimen is 25% of the width, it was restored to its original shape (repeat 7 to 10 times per minute).

- Continuous test: The bending state was continued for a certain period of time so that the distance between the transverse ends of the specimen was 25% of the transverse length.

- Memory test: After applying power to the specimen to achieve maximum discoloration, the power was turned off and maintained for a certain period of time.

all. Transmittance measurement: After applying power to the specimen to make the maximum discoloration state or the maximum coloring state, as shown in FIG. 2, four points (P2) with a separation distance (a) of 30 mm from the edge of the specimen (P2) and the center point of the specimen In (P1), the average transmittance of visible light was measured. The average visible light transmittance is an average value of values obtained by measuring transmittance at intervals of 5 nm at a wavelength in the range of 380 to 780 nm.

la. measurement data

- TT_0: transmittance measured in the state of maximum discoloration at the initial stage (before the test)

- TT_0': transmittance measured in the initial (before the test) state of maximum coloring

- TT_B30 : Transmittance measured in the state of maximum discoloration after repeating the bending test 30 times

- TT_B30' : Transmittance measured in the maximum colored state after repeating the bending test 30 times

- TT_B50 : Transmittance measured in the state of maximum discoloration after repeating the bending test 50 times

- TT_B50' : Transmittance measured in the maximum colored state after repeating the bending test 50 times

- TT_100H: Transmittance measured in the state of maximum discoloration after 100 hours of continuous testing

- TT_100H': transmittance measured in the maximum colored state after 100 hours of continuous testing

- TT_100H_B30: Transmittance measured in the state of maximum discoloration after performing the continuous test for 100 hours and then repeating the bending test 30 times

- TT_100H_B30' : Transmittance measured in the maximum colored state after performing the continuous test for 100 hours and then repeating the bending test 30 times

- TT_B30_M12H: The transmittance measured after repeating the bending test 30 times and performing the memory test for 12 hours in the state of maximum discoloration

- TT_B30_M12H': The transmittance measured after repeating the bending test 30 times and performing the memory test in the maximum coloration state for 12 hours

The measured data are summarized in Tables 2 to 5 in the format of Table 1 below.

Siheung items Early
(before the test) 30 episodes
flex 50 episodes
flex bent over
100 hours 100H +30 bends while bent 30 bends+
12H maintenance after coloring transmittance
(%) decolorization TT_0 TT_B30 TT_B50 TT_100H TT_100H_B30 TT_B30_M12H coloring TT_0' TT_B30' TT_B50' TT_100H' TT_100H_B30' TT_B30_M12H'

division restoration
discoloration layer
thickness
(nm) additive
content*
(parts by weight) Siheung items Early
(before the test) 30 episodes
flex 50 episodes
flex bent over
100H 100H +30 bends while bent 30 bends+
after coloring
12H maintenance Example
One 300 3 Transmittance*
(%) decolorization 67.3 67.2 67.0 67.2 67.0 66.9 coloring 13.0 12.9 13.1 12.9 13.2 - ΔTransmittance (%) 54.3 54.3 53.9 54.3 53.8 - Example
2 450 5 Transmittance*
(%) decolorization 67.5 67.4 67.3 67.3 67.2 67.0 coloring 13.1 13.0 13.2 13.0 13.2 - ΔTransmittance (%) 54.4 54.4 54.1 54.3 54.0 - Example
3 600 7 Transmittance*
(%) decolorization 67.6 67.6 67.5 67.6 67.3 67.1 coloring 13.3 13.2 13.4 13.3 13.7 - ΔTransmittance (%) 54.3 54.4 54.1 54.3 53.6 - * Additive content (parts by weight): content relative to 100 parts by weight of tungsten oxide in the reducing color change layer
* Transmittance: Measure at 5 nm intervals at a wavelength of 380 to 780 nm and calculate the average value

division restoration
discoloration layer
thickness
(nm) additive
content*
(parts by weight) Test Items Early
(before the test) 30 episodes
flex 50 episodes
flex 100H bent 100H +30 bends while bent 30 times bending + 12H maintenance after coloring Example
4 600 One Transmittance*
(%) decolorization 68.2 68.1 67.7 - - 65.5 coloring 13.2 13.3 14.0 - - - ΔTransmittance (%) 55.0 54.3 53.7 - - - Example
5 600 3 Transmittance*
(%) decolorization 68.0 68.0 67.8 - - 67.0 coloring 13.3 13.4 13.5 - - - ΔTransmittance (%) 54.7 54.6 54.3 - - - Example
6 600 9 Transmittance*
(%) decolorization 67.5 67.3 67.1 - - 64.0 coloring 13.5 13.6 13.8 - - - ΔTransmittance (%) 54.0 53.7 53.3 - - - * Additive content (parts by weight): content relative to 100 parts by weight of tungsten oxide in the reducing color change layer
* Transmittance: Measure at 5 nm intervals at a wavelength of 380 to 780 nm and calculate the average value

division restoration
discoloration layer
thickness
(nm) additive
content*
(parts by weight) Test Items Early
(before the test) 30 episodes
flex 50 episodes
flex 100H bent 100H +30 bends while bent 30 times bending + 12H maintenance after coloring Example
7 300 One Transmittance*
(%) decolorization 67.5 67.3 67.7 - - 67.1 coloring 13.0 13.3 14.0 - - - ΔTransmittance (%) Δ54.5 Δ54.0 Δ53.7 - - - Example
8 300 7 Transmittance*
(%) decolorization 67.0 66.8 67.8 - - 66.5 coloring 13.3 13.5 13.5 - - - ΔTransmittance (%) Δ53.7 Δ53.3 Δ54.3 - - - Example
9 300 9 Transmittance*
(%) decolorization 64.0 63.8 63.8 - - 59.5 coloring 14.8 15.0 15.1 - - - ΔTransmittance (%) Δ49.2 Δ48.8 Δ48.7 - - - * Additive content (parts by weight): content relative to 100 parts by weight of tungsten oxide in the reducing color change layer
* Transmittance: Measure at 5 nm intervals at a wavelength of 380 to 780 nm and calculate the average value

division restoration
discoloration layer
thickness
(nm) additive
content*
(parts by weight) Test Items Early
(before the test) 30 episodes
flex 50 episodes
flex 100H bent 100H +30 repetitions while bent 30 times bending + 12H maintenance after coloring comparative example
One 600 0 Transmittance*
(%) decolorization 68.3 68.2 66.5 - - - coloring 13.2 13.3 15.0 - - - ΔTransmittance (%) Δ55.1 Δ54.9 Δ51.5 - - - comparative example
2 900 0 Transmittance*
(%) decolorization 69.0 57.0 inoperable
(Front
crack) - - - coloring 12.5 21.0 - - - ΔTransmittance (%) Δ56.5 Δ36.0 - - - * Additive content (parts by weight): content relative to 100 parts by weight of tungsten oxide in the reducing color change layer
* Transmittance: Measure at 5 nm intervals at a wavelength of 380 to 780 nm and calculate the average value

e. Calculation of Equations Using Measured Data The following equations were calculated using the measured data and summarized in the table below.

(1) Change in transmittance before and after 30 repeated bending tests

△TT_B30 (%) = │TT_B30 - TT_0│

(2) Changes in transmittance operating range before and after 30 repeated bending tests

△TT_B30_d (%) = ││TT_B30 - TT_B30'│-│TT_0 - TT_0'││

(3) Change in transmittance before and after 50 repeated bending tests

△TT_B50 (%) = │TT_B50 - TT_0│

(4) Change in transmittance before and after the test held for 100 hours in a bent state

△TT_100H (%) = │TT_100H - TT_0│

(5) Change in transmittance after 30 repeated bending tests after holding for 100 hours in a bent state

△TT_100H_B30 (%) = │TT_100H_B30 - TT_0│

(6) After 30 times of repeated bending test, apply power to make the maximum discoloration state, then cut off the power and maintain for 12 hours, then change the transmittance

△TT_B30_M12H (%) = │TT_B30_M12H - TT_0│

unit:% △TT_B30
(One) △TT_B30_d
(2) △TT_B50
(3) △TT_100H
(4) △TT_100H_B30
(5) △TT_B30_M12H
(6) Example 1 0.1 0 0.3 0.1 0.3 0.4 Example 2 0.1 0 0.2 0.2 0.3 0.5 Example 3 0 0.1 0.1 0 0.3 0.5 Example 4 0.1 0.7 0.5 - - 2.7 Example 5 0 0.1 0.2 - - 1.0 Example 6 0.2 0.3 0.4 - - 3.5 Example 7 0.2 0.5 0.2 - - 0.4 Example 8 0.2 0.4 0.8 - - 0.5 Example 9 0.2 0.4 0.2 - - 4.5 Comparative Example 1 1.8 3.6 - - - - Comparative Example 2 crack crack - - - -

mind. Interpretation of results

As shown in the above table, in the electrochromic device of Comparative Example 1, microcracks occurred after the repeated bending test 30 times, so that the change in transmittance from the initial time exceeded 1%. In addition, in the electrochromic device of Comparative Example 2, a number of cracks occurred after repeated bending for 10 times, and the transmittance was greatly reduced, and during the repeated bending test of 30 times, a number of cracks occurred on the front surface, making operation impossible.

On the other hand, in the electrochromic devices of Examples 1 to 9, it was measured that the transmittance change was within 1% compared to the initial stage even after the repeated bending test 30 times.

In particular, the electrochromic elements of Examples 1 to 3 were measured to have transmittance changes of less than 1% compared to the initial stage after the test of repeating or continuing bending or the test of keeping the power turned off.

On the other hand, when looking at Examples 4 to 6, it was found that the color retention (memory) function and bending properties were affected by the additive content at a certain level of thickness. Specifically, in Example 4, microcracks occurred when repeated 50 times, and in Examples 4 and 6, after repeated bending 30 times, power was applied to create a maximum discoloration state, and then the transmittance was slightly decreased when the power was turned off and maintained for 12 hours. was lowered

In addition, when viewing Examples 7 to 9, when the thickness of the tungsten oxide was thin, it was found that the transmittance operating range and the memory function were affected by the additive content.

A-A': incision line
L: length of electrochromic element
D: distance between both ends of the electrochromic element
10: Windows
100: electrochromic element
110: first base layer
111: 1A primer layer
112: 1B primer layer
120: first barrier layer
121: 1A barrier layer
122: 1B barrier layer
123: 1C barrier layer
130: light transmission variable structure
131: first electrode layer
133: first color-changing layer
135: electrolyte layer
137: second color-changing layer
139: second electrode layer
140: second barrier layer
141: 2A barrier layer
142: 2B barrier layer
143: 2C barrier layer
150: second base layer
151: 2A primer layer
152: 2B primer layer
160: release film layer
161: adhesive layer
170: hard coating layer

Claims (9)

Electrochromic comprising a first color-changing layer comprising a first base layer, a second base layer, and a light-transmitting variable structure disposed therebetween, wherein the light-transmitting variable structure is adjustable in color and discoloration according to the application of power As a child,
In the test in which the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length is bent so that the distance between both ends in the horizontal direction is 75 mm for a certain period of time, it is defined in Equation (4) below The fourth transmittance change (ΔTT_100H) is within 3%, the electrochromic element:
△TT_100H (%) = │TT_100H - TT_0│ ... (4)
In the above formula (4)
TT_100H is the average visible light transmittance (%) of the electrochromic element measured in the state of maximum discoloration after performing the continuous test for 100 hours,
TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the sustain test.
According to claim 1,
The electrochromic element is
Based on the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length, the following equation (1) ), the first transmittance change (ΔTT_B30) defined in 1.5%, the electrochromic element:
△TT_B30 (%) = │TT_B30 - TT_0│ ... (1)
In the above formula (1)
TT_B30 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after repeating the bending test 30 times,
TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the bending test.
According to claim 1,
The electrochromic element is
Based on the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length, the following equation (2) ), the second transmittance change (ΔTT_B30_d) defined in 3%, the electrochromic element:
△TT_B30_d (%) = ││TT_B30 - TT_B30'│-│TT_0 - TT_0'││ ... (2)
In the above formula (2)
TT_B30 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after repeating the bending test 30 times,
TT_B30' is the average visible light transmittance (%) of the electrochromic element measured in the maximum colored state after repeating the bending test 30 times,
TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the bending test,
TT_0' is the average visible light transmittance (%) of the electrochromic element measured in the maximum colored state before the bending test.
According to claim 1,
The electrochromic element is
Based on the specimen of the electrochromic element having a size of 300 mm in width and 200 mm in length, the following formula (3) ), the third transmittance change (ΔTT_B50) defined in 3%, the electrochromic element:
△TT_B50 (%) = │TT_B50 - TT_0│ ... (3)
In the above formula (3)
TT_B50 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state after repeating the bending test 50 times,
TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the bending test.
3. The method of claim 2,
The electrochromic element is
When the bending test is repeated after performing the sustain test, the fifth transmittance change (ΔTT_100H_B30) defined in Equation (5) below is within 3%, the electrochromic device:
△TT_100H_B30 (%) = │TT_100H_B30 - TT_0│ ... (5)
In the above formula (5)
TT_100H_B30 is the average visible light transmittance (%) of the electrochromic element measured in a state of maximum discoloration after performing the sustain test for 100 hours and repeating the bending test 30 times,
TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the sustain test.
3. The method of claim 2,
The electrochromic element is
After repeating the bending test, applying power to make the maximum discoloration state, and then turning off the power and maintaining the memory test for a certain period of time, the sixth transmittance change (ΔTT_B30_M12H) defined in Equation (6) below is 3 %, which is an electrochromic element:
△TT_B30_M12H (%) = │TT_B30_M12H - TT_0│ ... (6)
In the above formula (6)
TT_B30_M12H is the average visible light transmittance (%) of the electrochromic element measured after repeating the bending test 30 times and performing the memory test for 12 hours in the maximum discoloration state,
TT_0 is the average visible light transmittance (%) of the electrochromic element measured in the maximum discoloration state before the bending test.
According to claim 1,
The first base layer and the second base layer are polymer films,
The first color-changing layer has a thickness of 300 nm to 600 nm,
The electrochromic device has a thickness of 20 μm to 1,000 μm.
According to claim 1,
The first base layer and the second base layer are each polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI), polycyclohexylenedimethylene terephthalate (PCT) , polyether sulfone (PES), nylon (nylon), polymethyl methacrylate (PMMA) and containing at least one selected from the group consisting of cycloolefin polymer (COP),
The first color-changing layer comprises 100 parts by weight of a reducible color-changing material and 3 to 7 parts by weight of a polymer resin,
The reducible color-changing material is titanium oxide, vanadium oxide, niobium oxide, chromium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, rhodium oxide, tantalum oxide, iridium oxide, tungsten oxide and a group consisting of viologen At least one selected from
The polymer resin is at least one selected from the group consisting of a silicone-based resin, an acrylic resin, a phenol-based resin, a polyurethane-based resin, a polyimide-based resin, and an ethylene vinyl acetate-based resin, an electrochromic device.
According to claim 1,
The light-transmitting variable structure
a first electrode layer under the first color-changing layer;
an electrolyte layer on the first color-changing layer;
a second color-changing layer on the electrolyte layer; and
Further comprising a second electrode layer on the second color-changing layer,
The first color-changing layer includes a reducing color-changing material and a polymer resin,
The second color-changing layer includes an oxidative color-changing material and a polymer resin.

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