Method for manufacturing smart window and smart window manufactured by the method

Abstract

To provide a method for manufacturing a smart window excellent in quality and appearance without causing liquid crystal unevenness even after joining base materials by stabilizing unevenness of pressure applied to a liquid crystal layer inside a dimming laminate when joining the base materials.SOLUTION: A step of laminating a film laminate including a light control laminate, an adhesive layer, and a substrate, a pre-bonding step, and a main bonding step, wherein the main bonding step includes a) a step of maintaining at 3.5 to 10bar for 15 to 60 minutes, and b) a step of maintaining at 1bar to 3bar for 70 to 100 minutes after the step a).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a smart window and to a smart window manufactured by said method. [Background technology]

[0002] Generally, glass windows of vehicles and other transportation means are often coated with an external light blocking coating. However, conventional glass windows of transportation means have a fixed transmittance, and the external light blocking coating also has a fixed transmittance. Therefore, such conventional transportation windows have a fixed overall transmittance, which can lead to accidents. For example, if the overall transmittance is set low, there is no problem during the daytime when there is sufficient surrounding light. However, there is a problem that drivers have difficulty properly checking the surroundings of the transportation means during times when there is insufficient surrounding light, such as at night. Alternatively, if the overall transmittance is set high, there is a problem that drivers may experience glare during times when there is sufficient surrounding light. For this reason, a variable transmittance optical laminate has been developed that can change light transmittance when a voltage is applied.

[0003] The variable transmittance optical stack is driven by applying a voltage to drive the liquid crystal to change the transmittance. The variable transmittance optical stacks developed to date are manufactured by forming a conductive layer for driving the liquid crystal on a separate substrate and combining it with other elements such as a polarizer.

[0004] For example, Japanese Patent Publication No. 2018-010035 discloses a variable transmittance optical laminate including a transparent conductive layer formed on a polycarbonate PC substrate of a predetermined thickness. Such variable transmittance smart windows require a liquid crystal layer to implement the variable transmittance function and are ultimately bonded to glass. However, when using conventional technologies, the liquid crystal layer in the light-control laminate is likely to be compressed during the glass bonding process, resulting in unevenness due to the fluidity of the liquid crystal. This can lead to the occurrence of liquid crystal irregularities in the final smart window that were not visible before glass bonding. Thinner light-control laminates, especially those with a structure in which the polarizer and conductive layer are in direct contact without a substrate between them, are more likely to develop liquid crystal irregularities due to the glass bonding pressure. Therefore, there is a need to develop a variable transmittance optical laminate that has a structure that can minimize the pressure applied to the liquid crystal layer and a bonding method that can eliminate pressure unevenness, thereby preventing liquid crystal irregularities even after glass bonding. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-010035 Summary of the Invention [Problem to be solved by the invention]

[0006] In order to solve the problems described above, the present invention aims to provide a method for manufacturing a smart window with excellent quality and appearance, in which the bonding of a substrate to a film laminate includes two or more steps, thereby stabilizing the uneven pressure applied to the liquid crystal layer inside the light-control laminate when the substrate is bonded, and preventing liquid crystal unevenness even after the substrate is bonded.

[0007] Another object of the present invention is to provide a method for manufacturing a smart window that can suppress liquid crystal unevenness that can occur in displays, particularly liquid crystal unevenness that is more likely to occur in light-control laminates manufactured by directly contacting the polarizer and conductive layer without including a substrate between them, by providing a manufacturing process in which the main bonding of the substrate to the film laminate is divided into two or more stages and the bonding is carried out gradually using different pressures.

[0008] Another object of the present invention is to provide a method for manufacturing a smart window including a film laminate further including a gap layer having optimal physical properties and structure for protecting a liquid crystal layer.

[0009] Another object of the present invention is to provide a method for manufacturing a smart window including a film laminate further including a surface protection layer having optimal physical properties and structure for protecting a liquid crystal layer.

[0010] Another object of the present invention is to provide a smart window that includes a light control laminate manufactured without a separate substrate for forming a conductive layer, and that has a significantly reduced thickness compared to conventional light control laminates.

[0011] Another object of the present invention is to provide a smart window including the film laminate, and a means of transportation, a wearable device, or a building fixture to which the smart window is applied.

[0012] However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0013] The present invention relates to a method for manufacturing a smart window, comprising the steps of laminating a film laminate including a light-control laminate, an adhesive layer, and a substrate; a preliminary bonding step; and a main bonding step, wherein the main bonding step comprises: a) maintaining the pressure at 3.5 to 10 bar for 15 to 60 minutes; and b) subsequent to step a), reducing the pressure to 1 bar to 3 bar and maintaining the pressure for 70 to 100 minutes.

[0014] In the present invention, the steps a) and b) may be carried out at a temperature of 50 to 110°C.

[0015] In the present invention, the step a) may be carried out at 3.5 to 6 bar.

[0016] In the present invention, the step b) may be carried out at 1 to 2 bar. In the present invention, the pre-bonding step is carried out at 0.1 to 3 bar, The method may include the steps of: S1) increasing the temperature to 40 to 90°C; S2) maintaining the temperature of S1); and S3) cooling to 0 to 30°C.

[0017] The present invention may further include a step of manufacturing a film laminate including a photochromic laminate, and the step of manufacturing the film laminate may include a step of forming a gap layer at the end of the photochromic laminate.

[0018] In the present invention, the gap layer has a storage modulus G' of 10 3 or 10 6 kPa, and the storage modulus G' at 100°C is 5 x 10 2 or 5 x 10 3 kPa and laminating the laminate to a thickness greater than that of the light-control laminate.

[0019] In the present invention, the step of producing the film laminate may include a step of laminating a surface protection layer on at least one of the upper and lower surfaces of the light-control laminate.

[0020] In the present invention, the step of producing the film laminate may include a step of laminating a surface protection layer on at least one of the upper and lower surfaces of the light-control laminate.

[0021] In the present invention, the surface protective layer is a low-temperature curable polyvinyl butyral (PVB) film that cures at a temperature of 90°C or less, and has a tensile modulus E' of 10 at 60°C. 8 or 10 10 Pa, 10 at 90°C 6 or 10 7 It may also be that of Pa.

[0022] In the present invention, the surface protective layer may include a polyvinyl butyral (PVB) film that is characterized by having no flowability at 100°C or less under a load of 21.6 kg, and having a melt flow rate (MFR) of 0.02 g / 10 min or less at 140°C under a load of 2.16 kg as measured in accordance with ASTM D1238.

[0023] The present invention provides a smart window manufactured by the above manufacturing method, wherein the smart window includes a light-control laminate, the light-control laminate including: a first polarizer; a first transparent conductive layer formed on the inner surface of the first polarizer; a second polarizer facing the first polarizer; a second transparent conductive layer formed on the inner surface of the second polarizer and facing the first transparent conductive layer; a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer; and an alignment film formed between the transparent conductive layer and the liquid crystal layer, wherein at least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with the first polarizer or the second polarizer. [Effects of the Invention]

[0024] According to the method for manufacturing a smart window of the present invention, in order to minimize the pressure applied to the liquid crystal layer, the main bonding step of bonding the substrate to the film laminate includes two or more steps with different pressures. This allows the film laminate, adhesive layer, and substrate to be bonded gradually, thereby stabilizing the uneven pressure applied to the liquid crystal layer when bonding the glass, preventing liquid crystal bias and uneven liquid crystal distribution, and allowing for the manufacture of a smart window with excellent appearance.

[0025] In addition, according to the method for manufacturing a smart window according to the present invention, the film laminate further includes a surface protection layer having optimal properties and structure for protecting the liquid crystal layer, thereby making it possible to manufacture a film laminate that significantly suppresses liquid crystal unevenness that may occur in a display.

[0026] In addition, according to the method for manufacturing a smart window according to the present invention, the film laminate further includes a gap layer having optimal physical properties and structure for protecting the liquid crystal layer, thereby making it possible to manufacture a film laminate that significantly suppresses liquid crystal unevenness that may occur in a display.

[0027] In addition, according to the method for manufacturing a smart window according to the present invention, the film laminate includes a light control laminate manufactured without including a separate substrate for forming a conductive layer, and therefore the thickness can be significantly reduced compared to conventional film laminates.

[0028] By applying the film laminate according to the present invention, it is possible to provide a smart window that does not cause unevenness in liquid crystal, and a means of transportation, a wearable device, or a building fixture to which the smart window is applied. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a flow chart showing a method for manufacturing a smart window according to an embodiment of the present invention in a process order. [Figure 2a] FIG. 2a shows a simplified diagram of the structure of a smart window according to one embodiment of the present invention. [Figure 2b]FIG. 2b shows a simplified diagram of the structure of a smart window according to one embodiment of the present invention. [Figure 3] FIG. 3 is a simplified diagram showing the structure of a light-control stack according to one embodiment of the present invention. [Figure 4a] FIG. 4a shows photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken by observing them on a backlight plate (light source) using a digital camera. [Figure 4b] FIG. 4b shows photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken by a digital camera on a backlight plate (light source). [Figure 4c] FIG. 4c shows photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken by a digital camera on a backlight plate (light source). [Figure 4d] FIG. 4d shows photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken by a digital camera on a backlight plate (light source). [Figure 4e] FIG. 4e shows photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken by a digital camera on a backlight plate (light source). [Figure 4f] FIG. 4f shows photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken by a digital camera on a backlight plate (light source). [Figure 5a] FIG. 5a shows photographs of the appearance evaluation results of the bonded articles of Comparative Examples 1 and 2 of the present invention, observed on a backlight plate (light source) using a digital camera. [Figure 5b] FIG. 5b shows photographs of the appearance evaluation results of the bonded articles of Comparative Examples 1 and 2 of the present invention, observed on a backlight plate (light source) using a digital camera. [Figure 6a] FIG. 6a shows photographs of the appearance evaluation results of the bonded articles of Reference Examples 1 to 4 of the present invention, taken by observing them with a digital camera on a backlight plate (light source). [Figure 6b]FIG. 6b shows photographs of the appearance evaluation results of the bonded articles of Reference Examples 1 to 4 of the present invention, taken by observing them with a digital camera on a backlight plate (light source). [Figure 6c] FIG. 6c shows photographs of the appearance evaluation results of the bonded articles of Reference Examples 1 to 4 of the present invention, taken by observing them with a digital camera on a backlight plate (light source). [Figure 6d] FIG. 6d shows photographs of the appearance evaluation results of the bonded articles of Reference Examples 1 to 4 of the present invention, taken by observing them with a digital camera on a backlight plate (light source). DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention relates to a method for manufacturing a smart window and a smart window manufactured thereby, which includes the steps of: laminating a film laminate including a light control laminate, an adhesive layer, and a substrate; a preliminary bonding step; and a main bonding step, wherein the main bonding step includes at least two or more processes, and the main bonding step includes the following two steps, a) and b), and the method includes two or more processes using different pressures, including: a) maintaining the pressure at 3.5 to 10 bar for 15 to 60 minutes; and b) following step a), reducing the pressure to 1 bar to 3 bar and maintaining the pressure for 70 to 100 minutes. By gradually bonding the film laminate, adhesive layer, and substrate, uneven pressure applied to the liquid crystal layer during glass bonding is stabilized, preventing liquid crystal bias and preventing liquid crystal unevenness in the smart window.

[0031] The light control laminate 10 of the present invention is particularly suitable for technical fields in which light transmittance can be changed by applying a voltage, and can be used, for example, in smart windows.

[0032] A smart window is an optical structure that controls the amount of light or heat passing through by changing its light transmittance in response to the application of an electrical signal. That is, a smart window can be changed between transparent, opaque, or translucent depending on the voltage applied, and is also called variable transmittance glass, light-control glass, or smart glass.

[0033] Smart windows can be used as partitions for dividing the interior space of vehicles and buildings or for privacy protection, or as light windows placed in openings in buildings. They can also be used for highway signs, bulletin boards, odometers, clocks, or advertising screens, and can be used to replace glass in vehicles such as windows or sunroofs in vehicles such as automobiles, buses, airplanes, ships, and trains.

[0034] The light-control laminate of the present invention can also be used in smart windows in the various technical fields mentioned above. However, since the transparent conductive layer is formed directly on the polarizer, no separate substrate is required for forming the conductive layer, resulting in a thin thickness and advantageous flexibility, making it particularly suitable for use in smart windows for vehicles or buildings. In one or more embodiments, smart windows using the light-control laminate of the present invention can be used in transportation, such as front windows, rear windows, side windows, and sunroofs of automobiles, or building fixtures. In addition to applications in blocking external light, they can also be used to divide the interior space of automobiles or buildings, such as interior partitions, or for privacy protection. They can also be used in wearable devices such as helmets, glasses, and watches.

[0035] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and, together with the above-described invention content, serve to further understand the technical concept of the present invention, and therefore the present invention should not be interpreted as being limited only to the matters depicted in these drawings.

[0036] The terms used herein are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular includes the plural unless otherwise specified in the context of the phrase. For example, the term "polarizer" used herein may refer to at least one polarizer selected from a first polarizer and a second polarizer, the term "transparent conductive layer" may refer to at least one transparent conductive layer selected from a first transparent conductive layer and a second transparent conductive layer, and the term "hard coating layer" may refer to at least one hard coating layer selected from a first hard coating layer and a second hard coating layer.

[0037] As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, operations and / or elements other than the stated components, steps, operations and / or elements. Like reference numerals refer to like elements throughout the specification.

[0038] Spatially relative terms such as "below," "bottom," "lower," "upper," "top," "top," and the like may be used to easily describe the relationship of one element or component to another, as illustrated in the figures. Spatially relative terms should be understood to encompass different orientations of elements in use or operation in addition to the orientation depicted in the figures. For example, if an element depicted in the figures is inverted, an element described as "below" or "below" another element may also be positioned "above" the other element. Thus, the exemplary term "below" may encompass both an orientation of below and above. Elements may be oriented in other directions, and thus the spatially relative terms may be interpreted accordingly.

[0039] As used herein, the "planar direction" can be interpreted as the direction perpendicular to the polarizer and / or transparent conductive layer, ie, the direction viewed from the user's viewing side.

[0040] As used herein, "substantially" can be interpreted to include not only being completely physically identical or identical, but also being within the range of error in measurement or manufacturing processes, for example, being within an error range of 0.1% or less.

[0041] <<Smart window manufacturing method>> The present invention relates to a method for manufacturing a smart window that prevents unevenness in the smart window. Specifically, the unevenness may be caused by a light-controlling laminate, and more specifically, the unevenness may be caused by a liquid crystal layer included in the light-controlling laminate being pressed during bonding of a substrate (glass) to the laminate during the smart window manufacturing process. Such unevenness is particularly likely to occur with thinner light-controlling laminates, which can be a fatal problem that reduces display quality. Therefore, the present invention provides a manufacturing method that can effectively manufacture an excellent smart window even in cases where liquid crystal unevenness due to the bonding pressure of the substrate is more likely to occur, such as in a light-controlling laminate manufactured by directly contacting a polarizer and a conductive layer without a substrate between them.

[0042] FIG. 1 is a flow chart showing a process sequence of a method for manufacturing a smart window according to an embodiment of the present invention, and FIGS. 2a and 2b show a simplified structure of a smart window 1000 according to an embodiment of the present invention.

[0043] 1 and 2a-2b, a method for manufacturing a smart window according to one embodiment of the present invention includes the steps of laminating a film laminate, an adhesive layer, and a substrate (S101); pre-bonding the laminate of the film laminate, the adhesive layer, and the substrate (S102); and finally bonding the pre-bonded laminate (S103). In one example of the present invention, the final bonding step (S103) includes at least two steps, including: a) maintaining a pressure of 3.5 to 10 bar for 15 to 60 minutes (S103-1); and b) following step a), reducing the pressure to a range of 1 to 3 bar and maintaining that pressure for 70 to 100 minutes (S103-2). Furthermore, the method for manufacturing a smart window according to the present invention may further include the step of manufacturing a film laminate including a light control laminate (S100) before the step of laminating the film laminate, the adhesive layer, and the substrate (S101).

[0044] <Step of Producing a Film Laminate Including a Light Control Laminate (S100)> The present invention can include manufacturing a film stack that includes a light management stack.

[0045] The film laminate manufactured through step S100 may refer to the photochromic stack 10 itself, or may refer to the photochromic stack 10 further including a gap layer 150 and / or a surface protective layer 140. For example, as shown in FIG. 2a, the film laminate of the present invention may refer to the photochromic stack 10, the gap layer 150, and the surface protective layer 140. Also, as shown in FIG. 2b, the film laminate of the present invention may refer to the adhesive layer 120-1, the substrate 130-1, the adhesive layer 120-2, and the substrate 130-2.

[0046] 2a, as an example of the present invention, a film laminate may include gap layers 150 as pillars on both side edges of the photochromic stack 10, and further include surface protection layers 140-1 and 140-2 on at least one surface of the photochromic stack 10. The surface protection layers 140-1 and 140-2 may be disposed facing each other at a certain distance via the gap layer 150 formed to surround the periphery of the photochromic stack 10, and the photochromic stack 10 is sealed in the space formed by the surface protection layers 140-1 and 140-2 and the gap layer 150.

[0047] In the present invention, the step of manufacturing a film laminate may include a step of manufacturing a light-controlling laminate and / or a step of laminating a gap layer on an end of the light-controlling laminate.

[0048] Steps for manufacturing the light-control stack 10 The steps for producing the light-control laminate of the present invention will be described in detail below, but the scope of the present invention is not limited thereto.

[0049] Specifically, in one example of the present invention, the present invention can include the steps of (p1) preparing a first polarizer, (p2) forming a first transparent conductive layer on a transparent substrate, (p3) forming a second transparent conductive layer on a second polarizer, (p4) coating a liquid crystal layer-forming composition on the second transparent conductive layer to form a liquid crystal layer, (p5) bonding the first transparent conductive layer in step (p2) so that it contacts the liquid crystal layer in step (p4), and (p6) bonding the first polarizer prepared in step (p1) to the transparent substrate in step (p5). Steps (p1) to (p5) may be omitted, combined, or performed in a different order as needed without departing from the scope of the present invention.

[0050] After step (p5), the first polarizer prepared in step (p1) is laminated with the second polarizer so that their absorption axes are perpendicular to each other. For example, the absorption axis of the second polarizer may be 0°, and the absorption axis of the first polarizer may be 90°. In this case, the absorption axes of the first polarizer and the second polarizer may be arranged perpendicular to each other in the planar direction, which may be advantageous for improving the transmittance variable range between the light-transmitting mode (ON) and the light-blocking mode (OFF) of the smart window driven by the liquid crystal.

[0051] FIG. 3 illustrates the structure of a light-controlling laminate 10 according to one embodiment of the present invention. Referring to FIG. 3, in one embodiment of the present invention, the light-controlling laminate 10 may include a first polarizer 11; a first transparent conductive layer 21 formed on the inner surface of the first polarizer; a second polarizer 12 facing the first polarizer 11; a second transparent conductive layer 22 formed on the inner surface of the second polarizer 12 and facing the first transparent conductive layer 21; a liquid crystal layer 40 disposed between the first transparent conductive layer 21 and the second transparent conductive layer 22; and alignment films 31 and 32 formed between the transparent conductive layers 21 and 22 and the liquid crystal layer 40. The light-controlling laminate may further include one or more layers selected from the group consisting of an adhesive layer, a bonding layer, a UV-absorbing layer, and / or a hard coating layer (not shown). A sealant 50 may also be included at an edge of the liquid crystal layer to secure a space for the liquid crystal layer.

[0052] The switchable stack 10 according to one embodiment of the present invention includes polarizers 11 and 12, transparent conductive layers 21 and 22, and a liquid crystal layer 40. The switchable stack 10 according to the embodiment of the present invention may be a variable transmittance optical stack, and the transmittance of the switchable stack 10 may be changed in response to the application of a voltage. For example, the switchable stack 10 may have a transmittance of 0.1 to 45% in response to the application of a voltage.

[0053] The polarizers 11 and 12 may include a polarizer and a protective layer formed on at least one side of the polarizer. Two different polarizers 11 and 12 may be positioned on both sides of the liquid crystal layer 40. When the polarizers 11 and 12 are positioned on both sides of the liquid crystal layer 40, the mutual angle between the absorption axes of the two different polarizers may be perpendicular or horizontal, preferably between 5 and 85° to ensure minimum transmittance. The polarizers transmit sporadic light in one direction and adjust the amount of light passing through using the polarization properties of the polarizers to control the transmittance of the optical stack. The protective layer may be a member that preserves the polarization properties of the polarizers from post-processing and external environments. In one embodiment, the protective layer may serve to provide a structural base on which transparent conductive layers 21 and 22 (described later) can be formed. In this case, the protective layer preferably has properties that facilitate the formation of the transparent conductive layers.

[0054] The protective layer may be provided on only one side of the polarizer or on both sides of the polarizer. When the polarizing plates 11 and 12 include multiple protective layers, the two different protective layers may contain substantially the same or similar materials. In one or more embodiments, the protective layer may contain polyester-based resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; cellulose-based resins such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based resins; polyethylene resins; polypropylene resins; acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; and cyclic olefin polymers (COPs).

[0055] The polarizer of the polarizing plate 11 may include a stretched polarizer or may be provided as a stretched polarizer. In one embodiment, the stretched polarizer may include a stretched polyvinyl alcohol (PVA)-based resin. The polyvinyl alcohol-based resin may preferably be a polyvinyl alcohol-based resin obtained by saponifying a polyvinyl acetate-based resin. Examples of polyvinyl acetate-based resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate with other monomers copolymerizable therewith. Examples of such other monomers include unsaturated carboxylic acid-based, unsaturated sulfonic acid-based, olefin-based, vinyl ether-based, and acrylamide-based monomers having an ammonium group. The polyvinyl alcohol-based resin may also be modified, such as polyvinyl formal or polyvinyl acetal modified with aldehydes.

[0056] The polarizing plate 11 may also include a coating-type polarizer. In one embodiment, the coating-type polarizer may be formed using a liquid crystal coating composition, for example, by coating the liquid crystal coating composition on the upper surface of the protective layer. In this case, the liquid crystal coating composition may include a reactive liquid crystal compound and a dichroic dye.

[0057] The reactive liquid crystal compound may include a reactive mesogen (RM) capable of exhibiting liquid crystallinity and / or a monomer molecule having a polymerizable terminal functional group and exhibiting a liquid crystal phase after a thermal or photocrosslinking reaction. When the reactive liquid crystal compound is polymerized by light or heat, it can form a polymer network while maintaining the liquid crystal alignment. By using the reactive liquid crystal compound, it is possible to form a thin-film polarizer with improved mechanical and thermal stability while maintaining the optical anisotropy and dielectric constant characteristics of the liquid crystal.

[0058] The dichroic dye is a component included in the liquid crystal coating composition that imparts polarization properties and has a property that the absorbance in the longitudinal direction of the molecule is different from that in the transverse direction. The dichroic dye may be a conventional or later-developed dichroic dye, such as an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, or an anthraquinone dye, which may be used alone or in combination.

[0059] The liquid crystal coating composition may further include a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye, such as propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, chloroform, etc. The liquid crystal coating composition may further include a labeling agent, a polymerization initiator, etc., within a range that does not impair the polarization properties of the coating film.

[0060] The polarizer 11 may also be formed by including an alignment member, for example, by applying and curing an alignment film coating composition containing an alignment polymer, a photopolymerization initiator, and a solvent onto a protective layer to form the alignment member, and then applying and curing the liquid crystal coating composition onto the alignment member. The alignment polymer is not particularly limited, but may be a polyacrylate resin, a polyamic acid resin, a polyimide resin, a polymer containing a cinnamate group, or the like. Conventional or later-developed polymers capable of exhibiting alignment may also be used.

[0061] The polarizing plate 11 included in the light-controlling laminate may further include a functional coating layer such as an overcoat layer and / or an optical functional layer to improve the surface hardness of the polarizer and the polarizing plate, and in one or more embodiments, may further include one or more layers selected from the group consisting of a protective layer, a phase difference adjusting layer, and / or a refractive index adjusting layer (not shown).

[0062] In one specific embodiment, the polarizer may further include an overcoat layer as a type of functional coating layer. For example, the overcoat layer may be located on the upper surface of the layer formed from the liquid crystal coating composition and may be provided facing the member having alignment properties. In one embodiment, a protective film may be further provided on the upper surface of the overcoat layer. In this case, the polarizer may have a laminated structure of the member having alignment properties - the layer formed from the liquid crystal coating composition - the overcoat layer - the protective film, thereby further improving mechanical durability while maintaining a certain level of transmittance.

[0063] The polarizer 11 may include an optical functional layer to improve the optical properties of the optical laminate. The optical functional layer may be provided on at least one surface of the protective layer, for example, on the upper surface of the protective layer. The optical functional layer is not particularly limited as long as it reinforces or complements the optical function of the polarizer 11. For example, a quarter-wave plate (¼ wave plate) or a half-wave plate (½ wave plate) for retarding the phase of light may be used, and these may be used alone or in combination. The retardation film may be manufactured including an obliquely stretched resin film, a liquid crystal coating layer, etc., and conventional or later-developed retardation films may be used.

[0064] In one or more embodiments, the polarizers 11 and 12 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm, which allows the polarizers 11 and 12 to maintain their optical properties while enabling the manufacture of a thin light-control laminate.

[0065] The polarizer 11 may have a curved shape in order to manufacture an optical laminate having a curved surface. For example, the polarizer 11 may be formed in a curved shape toward one of two different polarizers 11 stacked on both sides of the liquid crystal layer 40.

[0066] The refractive index adjustment layer (not shown) is provided to compensate for the transmittance difference of the light-control laminate due to the transparent conductive layers 21 and 22 described below, and may serve to improve visibility by reducing the refractive index difference. The refractive index adjustment layer may also be provided to correct the hue caused by the transparent conductive layers 21 and 22 described below. Meanwhile, when the transparent conductive layers 21 and 22 described below have a pattern, the refractive index adjustment layer can compensate for the transmittance difference between the patterned region where the pattern is formed and the non-patterned region where the pattern is not formed.

[0067] Specifically, when the transparent conductive layers 21 and 22 are stacked adjacent to other components (e.g., polarizers) with different refractive indices, the difference in refractive index between the adjacent layers can cause differences in light transmittance. In particular, when a pattern is formed on the transparent conductive layer, the patterned and non-patterned regions can be visually distinguishable. Therefore, the refractive index-adjusting layer compensates for the refractive index, thereby reducing the difference in light transmittance of the light-control stack. In particular, when a pattern is formed on the transparent conductive layer, the patterned and non-patterned regions can be visually distinguishable. The refractive index of the refractive index-adjusting layer may be preset to be greater than the refractive index of the protective layer of the polarizers 11 and 12 and less than the refractive index of the transparent conductive layers 21 and 22. The refractive index may be appropriately selected depending on the materials of the polarizers 11 and 12 and the transparent conductive layers 21 and 22, but is preferably 1.4 to 2.6, and more preferably 1.4 to 2.4. By setting the refractive index of the refractive index adjustment layer to a predetermined value in this manner, it is possible to prevent light loss due to a sharp difference in refractive index between the polarizing plates 11 and 12 and the transparent conductive layers 21 and 22. The refractive index adjustment layer is not particularly limited as long as it can prevent a sharp difference in refractive index between the polarizing plates and the transparent conductive layers.

[0068] The transparent conductive layers 21 and 22 may be formed on one surface of the polarizing plates 11 and 12 , and preferably may be formed in direct contact with the polarizing plates 11 and 12 .

[0069] The transparent conductive layers 21 and 22 are provided to drive the liquid crystal layer 40, and in one embodiment, at least one of the first transparent conductive layer 21 and the second transparent conductive layer 22 may be formed in direct contact with the first polarizer 11 or the second polarizer 12. For example, as shown in FIG. 1, the first transparent conductive layer 21 and the second transparent conductive layer 22 may be formed in direct contact with the first polarizer 11 and the second polarizer 12, respectively.

[0070] Conventional light-control laminates used in the manufacture of smart windows and the like are manufactured by forming a conductive layer for driving liquid crystals on one side of a substrate and bonding the other side of the substrate to a polarizer. However, the light-control laminate of the present invention does not require a separate substrate for forming the conductive layer, and instead forms the conductive layer directly on one side of the polarizer, thereby reducing the thickness of the laminate and improving the transmittance and bending characteristics in the transmission mode.

[0071] Being in direct contact with the polarizers 11 and 12 means that the transparent conductive layers 21 and 22 share a contact surface with the polarizers and are provided on the polarizers without a separate substrate. For example, the transparent conductive layers 21 and 22 may be formed by deposition on the upper surfaces of the protective layers formed on the polarizers 11 and 12.

[0072] In one embodiment, the transparent conductive layers 21 and 22 may be formed by direct deposition on one surface of the polarizers 11 and 12. In this case, the transparent conductive layers 21 and 22 may be formed by directly contacting the pretreated surface of the polarizers 11 and 12 after pretreating the one surface of the polarizers 11 and 12 with a corona treatment or plasma treatment in order to improve adhesion to the polarizers 11 and 12. The pretreatment is not limited to a corona treatment or a plasma treatment, and any conventional or later-developed pretreatment process may be used within the scope of the present invention.

[0073] In another embodiment of the present invention, the transparent conductive layer may be formed in direct contact with the polarizing plate, with an easy-adhesion layer provided on one side of the polarizing plate sandwiched therebetween, in order to improve adhesion strength with the polarizing plate.

[0074] The transparent conductive layers 21 and 22 preferably have a visible light transmittance of 50% or more, and may include, for example, one or more materials selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires. However, the present invention is not limited thereto, and conventional or later developed transparent conductive layer materials may be used.

[0075] In one or more embodiments, the transparent conductive oxide may include one or more selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), fluorine tin oxide (FTO), zinc oxide (ZnO), etc. The metal may include one or more selected from the group consisting of gold (Au), silver (Ag), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), and alloys containing at least one of these metals, such as a silver-palladium-copper (APC) alloy or a copper-calcium (CuCa) alloy. The carbon-based material may include at least one selected from the group consisting of carbon nanotubes (CNTs) and graphene.The conductive polymer may be a conventional or later developed conductive polymer material, for example, polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, polyacetylene, polydiacetylene, polyphenylene, polyphenylene vinylene, polyphenylene sulfide, polythienylene vinylene, polythiophene vinylene, polyfluorene, polypyrrole, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, poly(3,4-ethylenedioxythiophene):camphorsulfonic acid, poly(3,4-ethylenedioxythiophene):toluenesulfonic acid, poly(3,4-ethylenedioxythiophene): The conductive ink may include one or more selected from the group consisting of poly(3,4-ethylenedioxythiophene):dodecylbenzenesulfonic acid, polyaniline:polystyrenesulfonate, polyaniline:camphorsulfonic acid, polypyrrole:polystyrenesulfonate, polypyrrole:camphorsulfonic acid, polypyrrole:toluenesulfonic acid, polypyrrole:dodecylbenzenesulfonic acid, polythiophene:polystyrenesulfonate, polythiophene:camphorsulfonic acid, polythiophene:toluenesulfonic acid, and polythiophene:dodecylbenzenesulfonic acid, and is preferably poly(3,4-ethylenedioxythiophene). The conductive ink may be an ink containing a metal powder and a curable polymer binder, and the nanowires may be, for example, silver nanowires (AgNWs). In one embodiment of the present invention, the transparent conductive layer 120 preferably includes a conductive polymer such as polyethylenedioxythiophene (PEDOT).

[0076] The transparent conductive layer 120 may be formed by a deposition process such as CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), or PECVD (Plasma Enhanced Chemical Vapor Deposition), a printing process such as screen printing, gravure printing, reverse offset, or inkjet, or a dry or wet plating process. The transparent conductive layers 21 and 22 may also be formed as a two-layer structure using a combination of the above materials. For example, the transparent conductive layers 21 and 22 may be formed as a two-layer structure including a metal layer and a transparent conductive oxide layer to reduce reflectance and increase transmittance of incident light.

[0077] In one embodiment, the first transparent conductive layer 21 and the second transparent conductive layer 22 may have a surface that contacts the liquid crystal layer 40 that is rubbed and aligned. Unlike transparent conductive layers containing metal components, the conductive polymer contained in the transparent conductive layers 21 and 22 of the present invention can form grooves on the surface, thereby aligning the liquid crystal compound in the liquid crystal layer at a desired position and direction. In this case, the transparent conductive layers 21 and 22 can function as electrodes for driving the liquid crystal layer and as alignment layers. Since no separate alignment layer is required, a thinner light-control stack can be manufactured and the manufacturing process can be simplified.

[0078] To provide the rubbing-oriented transparent conductive layers 21 and 22, a rubbing method using a rubbing process and a photo-alignment method using ultraviolet light can be used. Generally, the photo-alignment method has weaker surface anchoring energy than the rubbing method, so it is preferable that the transparent conductive layers 21 and 22 of the present invention have their surfaces in contact with the liquid crystal layer 40 oriented by rubbing alignment using a rubbing method.

[0079] The liquid crystal layer 40 is driven by an electric field. The liquid crystal layer 40 may be located between first and second polarizers (11 and 12) located in the light control region of the light control laminate 10. In one embodiment, the liquid crystal layer 40 may be located in the space provided by a sealant 50 and spacers (not shown) between the first and second polarizers (11 and 12) or the space provided by a sealant 50 and spacers (not shown) between the first and second alignment films (31 and 32) in the light control region. In addition, the liquid crystal layer 40 can adjust the transmittance of light incident from an external light source by the electric field formed between the first and second conductive layers (21 and 22).

[0080] In one or more embodiments, the liquid crystal layer 40 may be driven by any one of the driving methods selected from the group consisting of TN (Twisted nematic), STN (Super-twisted nematic), IPS (In-plane switching), FFS (Fringe field switching), PLS (Plane line switching), AH-IPS (Advanced high-performance IPS), PSA (Polymer sustained alignment), and VA (Vertical alignment), or any conventional or later developed liquid crystal driving method may be applied.

[0081] According to another embodiment of the present invention, the liquid crystal layer 40 may include one or more spacers selected from the group consisting of ball spacers and column spacers, and ball spacers are particularly preferred. The number of ball spacers may be one or more, and the diameter of the ball spacers is preferably 1 to 10 μm. Furthermore, when viewed from the planar direction, the area of ​​the ball spacers in the liquid crystal layer 40 (i.e., the light control region) is preferably 0.01 to 10% of the area of ​​the liquid crystal layer 40 in terms of improving user visibility and transmittance in the light-transmitting mode.

[0082] The alignment films 31 and 32 may have substantially the same properties as those described above for the alignment-imparting material, and are not particularly limited as long as they are capable of imparting alignment to the liquid crystal compound. Preferably, they may include a photoalignable or photocurable polymer. For example, the alignment films 31 and 32 may be fabricated by applying and curing an alignment film coating composition including a photoalignable or photocurable polymer, a photopolymerization initiator, and a solvent. For example, the alignment films 31 and 32 may be formed by applying an alignment material such as polyimide and then performing a rubbing process.

[0083] The sealant 50 is used to bond two different polarizers and may be positioned in the inactive region between the two different polarizers. The sealant 50, together with a spacer, can secure a space for the liquid crystal layer between the two different polarizers. The presence of the sealant at the edge of the liquid crystal layer can further reduce the pressure applied to the liquid crystal layer during the glass bonding process described below. The thickness of the sealant is not limited.

[0084] The sealant 50 may include a curable resin as a base resin. The base resin may be a UV-curable resin or a thermosetting resin, which are known in the art for use as sealants. The UV-curable resin may be a polymer of a UV-curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer.

[0085] The base resin of the sealant 50 may be, for example, an acrylate-based resin, an epoxy-based resin, a urethane-based resin, a phenol-based resin, or a mixture of these resins. In one embodiment, the base resin may be an acrylate-based resin, and the acrylate-based resin may be a polymer of an acrylic monomer. The acrylic monomer may be, for example, a multifunctional acrylate. In another embodiment, the sealant may further include a monomer component in the base resin. The monomer component may be, for example, a monofunctional acrylate. In this specification, a monofunctional acrylate may refer to a compound having one acrylic group, and a multifunctional acrylate may refer to a compound having two or more acrylic groups. The curable resin may be cured by ultraviolet irradiation and / or heating. The ultraviolet irradiation conditions or heating conditions may be appropriately set within a range that does not impair the objectives of the present application. The sealant may further include an initiator, for example, a photoinitiator or a thermal initiator, if necessary.

[0086] The method for manufacturing the light control laminate of the present invention is not particularly limited as long as it is a method for realizing the above-described light control laminate. For example, the transparent conductive layers 21 and 22 and the refractive index control layer (not shown) may be deposited by a deposition method commonly used in the art, and may be formed by selecting an appropriate process from among coating processes such as spin coating, roller coating, bar coating, dip coating, gravure coating, curtain coating, die coating, spray coating, doctor coating, and kneader coating; printing processes such as screen printing, spray printing, inkjet printing, relief printing, intaglio printing, and planographic printing; and vacuum film formation methods such as CVD (chemical vapor deposition), PVD (physical vapor deposition), PECVD (plasma-enhanced chemical vapor deposition), and sputtering.

[0087] The light-control laminate of the present invention may have a thickness of 0.300 mm to 0.450 mm. Generally, light-control laminates having a thickness within this range are excessively thin, and therefore the influence of pressure during glass bonding tends to be more pronounced, making them more susceptible to unevenness. However, a smart window manufactured using the light-control laminate of this thickness according to the manufacturing method of the present invention can significantly suppress liquid crystal unevenness.

[0088] Preferably, the photochromic laminate of the present invention may have a thickness of 0.32 to 0.40 mm. When the thickness of the photochromic laminate satisfies the above range, it is possible to form a gap layer containing a polyvinyl butyral (PVB) film, which will be described later, thicker than the thickness of the photochromic laminate.

[0089] Film laminate manufacturing steps The present invention relates to a method for manufacturing a smart window with excellent quality and appearance, in which the bonding of a substrate to a film laminate includes two or more steps, thereby stabilizing uneven pressure applied to the liquid crystal layer inside the light control laminate during bonding of the substrate, and preventing liquid crystal irregularities even after bonding of the substrate. Specifically, as shown in Figure 2a, the film laminate may further include a gap layer 150 and / or surface protection layers 140-1, 140-2.

[0090] For example, the gap layer and surface protection layer are intended to suppress unevenness due to the light-controlling laminate. More specifically, the unevenness may be caused by the liquid crystal layer contained in the light-controlling laminate being pressed during the process of bonding glass to the laminate during the smart window manufacturing process. Such unevenness is particularly likely to occur with thinner light-controlling laminates, which can be a fatal problem that reduces the quality of displays. Therefore, the present invention provides a method for manufacturing a film laminate that can effectively manufacture an excellent smart window even in cases where liquid crystal unevenness due to glass bonding pressure is more likely to occur, such as in a light-controlling laminate manufactured by directly contacting the polarizer and conductive layer without using a substrate between them. More preferably, it is preferable to include a gap layer 150 and surface protection layers 140-1 and 140-2 at the ends of the light-controlling laminate 10 in order to minimize the pressure applied to the liquid crystal layer.

[0091] Hereinafter, the step of laminating a surface protective layer and the step of laminating a gap layer on the end of the light-control laminate of the present invention will be described in detail, but the scope of the present invention is not limited thereto.

[0092] Laminating surface protection layers 140-1 and 140-2 The surface protection layer, which is relatively thin and included on one or both sides of the light-control laminate (i.e., POL CELL), can improve defects caused by bonding pressure during the bonding process, prevent liquid crystal bias that can occur due to uneven pressure applied to the liquid crystal layer, and solve the problem of liquid crystal unevenness. For example, when one or more ultra-thin polyvinyl butyral (PVB) films are further included between the light-control laminate and a substrate such as glass, and / or an adhesive layer included to prevent the glass (substrate) from shattering, the light-control laminate and / or the liquid crystal in the light-control laminate are more effectively protected from damage caused by external physical pressure, such as compression. This is a characteristic achieved by eliminating uneven bias of liquid crystal (liquid phase) when bonding under pressure, due to the characteristics of polyvinyl butyral (PVB) film, which hardens at a relatively low temperature.

[0093] To this end, in the present invention, the surface protective layers 140-1 and 140-2 are characterized by a thickness of 0.01 mm to 0.35 mm and may be made of a low-temperature curable polyvinyl butyral (PVB) film that cures at temperatures below 90°C. A 0.05 mm-thick polyvinyl butyral (PVB) thin film may be used. The low-temperature curable polyvinyl butyral (PVB) film cures at temperatures below 90°C, preferably between 60°C and 90°C. This ensures adhesion to typical polyvinyl butyral films used in bonding glass, while minimizing the pressure applied to the liquid crystal layer, especially when applied to displays and / or display devices with thin liquid crystals. Furthermore, the PVB film has flexibility at the bonding temperature of 60°C to 90°C, which is the bonding temperature of the substrate (glass) described below, and thus has the advantage of being able to absorb the pressure applied to the liquid crystal layer in the light-controlling laminate. If the bonding temperature is below 60°C, the bonding will not be performed properly, and if it exceeds 90°C, the polarizer may be thermally damaged.

[0094] The low-temperature curing polyvinyl butyral (PVB) film contained in the surface protective layer has a tensile modulus E' of 10 8 or 10 10 Pa, 10 at 90°C 6 or 10 7 Pa, preferably 10 at 60°C 9 Pa, 10 at 90°C 6 The film may be a low-temperature curable polyvinyl butyral (PVB) film having a tensile modulus E' of 100 Pa. A polyvinyl butyral (PVB) film satisfying the above range of tensile modulus E' has the advantage of being able to more effectively reduce damage to the light-controlling laminate caused by high pressure.

[0095] The low-temperature curable polyvinyl butyral (PVB) film contained in the surface protective layer may be non-flowable at temperatures below 100°C under a load of 21.6 kg, and may have a melt mass-flow rate (MFR) of 0.02 g / 10 min or less at 140°C under a load of 2.16 kg as measured according to ASTM D1238. The melt flow rate is a standard physical property measured by measuring the mass of a thermoplastic material passing through a die with specified dimensions and properties at a specified temperature and load within 10 minutes, and is used as a criterion for evaluating the processability of a resin. Specifically, the melt flow rate measures the melt flowability of a thermoplastic polymer and is also called the melt flow rate or melt flow index. It is measured according to standard experimental methods in accordance with ASTM D1238 and ISO 1133 and is defined as the weight of a resin flowing in a molten state through an orifice under specified temperature and load conditions for 10 minutes. Melt viscosity is significantly dependent on molecular weight; the higher the molecular weight, the more entanglement occurs and the higher the melt viscosity. In this case, it is preferable to select a material for the film contained in the surface protection layer that has a melt flow rate (MFR) that is easy to form, is processable, and has a melt flow rate that is low enough to have sufficient mechanical strength considering that it will be contained in the final product.

[0096] The polyvinyl butyral (PVB) film contained in the surface protective layer of the present invention has low-temperature curing properties, providing crosslinking reactivity without the need for high heat, thereby maintaining the transparency of the coating layer. Furthermore, since high heat is not used during curing, it is possible to prevent the denaturation of other laminates, such as the resins bonded to the film.

[0097] Table 1 below shows the melt flow rate (MFR) of a 0.05 mm thick polyvinyl butyral (PVB) film included in the surface protective layer according to one embodiment of the present invention, measured according to ASTM D1238.

[0098] [Table 1]

[0099] Referring to Table 1 above, in the case of a polyvinyl butyral (PVB) thin film, no flow was observed at 100°C under a load of 21.6 kg, but a melt flow rate of 0.02 g / 10 min or less was measured at 140°C under a load of 2.16 kg. That is, the polyvinyl butyral (PVB) film included in one embodiment of the present invention exhibits curing properties at relatively low temperatures and is required to have excellent structural performance in a high temperature range, so it is preferable that it comprises one or more laminated thin films each having a thickness of about 0.05 mm. From the viewpoint of forming a sealant 50, the total area of ​​the surface protective layer preferably exceeds 100% of the area of ​​the photochromic laminate in contact with the surface protective layer, and more preferably may be 101 to 150% of the area of ​​the photochromic laminate.

[0100] Laminating the gap layer 150 The film laminate of the present invention may further include a step of laminating a gap layer 150 on the end of the light control laminate 10. Specifically, in one example of the present invention, the step of laminating a gap layer on the end of the light control laminate of the present invention may include a step of laminating a polyvinyl butyral (PVB) film thicker than the light control laminate.

[0101] In the present invention, in order to laminate the gap layer thicker than the light-control laminate, specifically, after checking the total thickness of the light-control laminate, a polyvinyl butyral (PVB) film may be laminated (placed) thicker than that thickness, and then the gap layer may be manufactured through a pre-bonding and main bonding step.

[0102] In the present invention, the gap layer is formed like a pillar at the end of the light-controlling stack in order to minimize the pressure directly applied to the liquid crystal layer in the light-controlling stack, and is characterized by being thicker than the thickness of the light-controlling stack to achieve this purpose.

[0103] For example, the thickness of the gap layer may be preferably in the range of 101 to 120% of the thickness of the photochromic stack. If the thickness exceeds this range, the gap layer may interfere with the bonding between the photochromic stack, the surface protection layer, and the substrate, resulting in black spots and manufacturing defects.

[0104] In one embodiment of the present invention, the gap layer has a storage modulus G' at 60°C of 10 3 or 10 6 kPa, and the storage modulus G' at 100°C is 5 x 10 2 or 5 x 10 3The storage modulus may be, but is not limited to, 0.1 kPa. If the storage modulus satisfies the above range, it can alleviate stress applied during subsequent bonding of substrates in the manufacture of smart windows, thereby effectively reducing unevenness in the liquid crystal layer. More specifically, even if the gap layer is designed to be thicker than the light-controlling laminate, if only a resin with hard properties is used, defects may occur during the subsequent bonding of the substrates. On the other hand, even if the gap layer is designed to be thicker than the light-controlling laminate, if only a resin with soft properties is used, the gap layer may not be able to sufficiently alleviate the pressure applied to the light-controlling laminate during the subsequent bonding of the substrates. Therefore, the gap layer preferably satisfies the above storage modulus range. As long as the gap layer satisfies the above storage modulus range and is thicker than the light-controlling laminate, it may include a low-temperature curable polyvinyl butyral (PVB) film. The type of PVB film is not limited, but preferably, the low-temperature curable polyvinyl butyral (PVB) film contained in the surface protective layer described above can be used as is.

[0105] The low-temperature curing polyvinyl butyral (PVB) film may be cured at a temperature of 90°C or less, but is not limited thereto. For example, two or more low-temperature curing polyvinyl butyral (PVB) films may be cured at a temperature of 90°C or less, but is not limited thereto. The low-temperature curing polyvinyl butyral (PVB) film has the advantage of being flexible at the substrate (glass) bonding temperature of 60 to 90°C, which will be described later, and thus capable of absorbing the pressure applied to the liquid crystal layer in the light-control laminate through bonding. Bonding temperatures below 60°C may not be performed properly, while temperatures above 90°C may cause thermal damage to the polarizer.

[0106] The film laminate of the present invention can have a storage modulus sufficient to absorb pressure by including and laminating the low-temperature curable polyvinyl butyral (PVB) film and / or by adjusting the type and thickness of the included polyvinyl butyral (PVB) film and the number of layers to be laminated.

[0107] Preferably, the gap layer of the present invention may be a multi-layer structure including two or more layers of film. In one example of the present invention, the gap layer may include multiple layers of polyvinyl butyral (PVB) film. Specifically, because PVB is an elastic material, when it is included in a light-controlling laminate for manufacturing a smart window, the temperature and pressure applied during the bonding process can damage the light-controlling laminate including the liquid crystal layer, potentially resulting in defects such as liquid crystal bias and unevenness. Therefore, in the film laminate of the present invention, a gap layer thicker than the thickness of the light-controlling laminate is formed. To form a gap layer that exceeds the thickness of the light-controlling laminate and can adequately relieve the pressure generated during bonding, the commonly used single 0.38 mm polyvinyl butyral (PVB) film alone is insufficient, so multiple layers of PVB film may be laminated.

[0108] More preferably, the gap layer has a tensile modulus E' of 10 at 60°C. 8 or 10 10 Pa, 10 at 90°C 6 or 10 7The light-controlling laminate may include a film having a tensile modulus of E', preferably a polyvinyl butyral (PVB) film, particularly a 0.05 mm PVB film, that satisfies the tensile modulus E'. When a polyvinyl butyral (PVB) film satisfying the tensile modulus E' is included, a gap layer thicker than the light-controlling laminate can be formed by including a PVB film with high hardness, which has the advantage of more effectively reducing damage to the light-controlling laminate due to high pressure. Furthermore, impact resistance can be imparted to a smart window manufactured by subsequently laminating a substrate. According to one embodiment of the present invention, it is particularly preferred to form a gap layer thicker than the light-controlling laminate and having a desirable storage modulus by laminating two to eight thin 0.05 mm PVB films alone, as described above, among the polyvinyl butyral (PVB) films used in the surface protection layer. This thin 0.05 mm PVB film has excellent structural properties, such as processability and strength.

[0109] Meanwhile, in the present invention, the gap layer may further include a 0.38 mm polyvinyl butyral (PVB) film having a thermal conductivity of 0.2 W / mK. When a polyvinyl butyral (PVB) film satisfying the thermal conductivity is included, a gap layer thicker than the light-controlling laminate can be formed by including a soft polyvinyl butyral (PVB) film, which may facilitate bonding. Specifically, with regard to the storage modulus of the gap layer, if the gap layer is too hard, it may not be sufficiently pressed when later bonding a surface protective layer and / or substrate to the light-controlling laminate, making bonding difficult. According to one embodiment of the present invention, when the thickness of the light-controlling laminate is 0.39 mm, a gap layer thicker than the light-controlling laminate and having a desirable storage modulus can be formed by laminating a 0.05 mm polyvinyl butyral (PVB) film satisfying the tensile modulus and a 0.38 mm polyvinyl butyral (PVB) film satisfying the thermal conductivity. The thermal conductivity is collected and measured at 23°C and 50°C using a thermal constants analyzer by a TPS (Transient Plane Source) method.

[0110] Meanwhile, in the present invention, the gap layer may further include a 0.38 mm thick polyvinyl butyral (PVB) film having a specific heat of 1.9 to 2.3 kJ / (kg·K). The specific heat was measured using a differential scanning calorimeter (DSC).

[0111] Furthermore, 0.38mm PVB with a thermal conductivity of 0.2 w / mK and / or a specific heat of 1.9 to 2.3 kJ / (kg·K) can transmit 88.8% or more of visible light and preferably has a UV transmittance of 0.6% or less. When these conditions are met, the polyvinyl butyral (PVB) film contained in smart windows can block UV rays, improving the quality of the smart windows.

[0112] In the present invention, the polyvinyl butyral (PVB) film contained in the gap layer may be the same as that used in the surface protection layer and the adhesive layer described below.

[0113] The gap layer is formed by laminating the layers in the desired manner, and the laminating position and order are not specified.

[0114] <Lamination step (S101)> A method for manufacturing a smart window according to an embodiment of the present invention includes the step (S101) of preparing a film laminate and laminating adhesive layers 120-1, 120-2 and substrates 130-1, 130-2 on one or both sides of the film laminate. In one embodiment, the adhesive layers 120-1, 120-2 may be formed on one side of the surface protection layers 140-1, 140-2 or on one side of the light control laminate 10 by lamination.

[0115] The lamination step may further include a fixing step before the pre-bonding step. In order to facilitate pre-bonding and main bonding in a state where the film laminate, adhesive layer, and substrate are laminated, a frame is fixed by taping or the like. This may be a conventional or later-developed method, such as a method of sandwiching a ring that can surround the entire side and fixing it with adhesive tape.

[0116] The lamination step may further include a subsequent vacuum suction step. A vacuum suction process may be performed to ensure stable bonding of the film laminate and the substrate. This creates a near-vacuum state between the film laminate and the substrate, trapping air between them and preventing bubbles from forming after bonding or optical distortion after completion. This may be achieved using vacuum rubber bags or other conventional or later-developed methods.

[0117] Laminating adhesive layers 120-1 and 120-2 The adhesive layers 120-1 and 120-2 may be manufactured using an adhesive or pressure-sensitive adhesive. They preferably have suitable adhesive strength to prevent peeling, bubbles, and the like during handling of the light-control laminate, as well as transparency and thermal stability. The adhesive layers may be conventional or future adhesive films. From the perspective of safety (glass shattering, penetration), the adhesive layers preferably include a low-temperature curing polyvinyl butyral (PVB) film. A low-temperature curing polyvinyl butyral (PVB) film has flexibility even at low temperatures, allowing it to absorb pressure applied to the film laminate and achieve the desired initial adhesive strength even when cured at low temperatures. For example, the adhesive layers 120-1 and 120-2 may be made of the same material as the polyvinyl butyral (PVB) film contained in the surface protection layer and gap layer of the film laminate, but this is not limited thereto.

[0118] The adhesive may be a conventional or later developed adhesive, for example, a photocurable adhesive, a thermosetting adhesive, or a pressure sensitive adhesive.

[0119] The photocurable adhesive exhibits strong adhesive strength by crosslinking and curing when exposed to active energy rays such as ultraviolet (UV) and electron beam (EB), and may be composed of reactive oligomers, reactive monomers, photopolymerization initiators, etc.

[0120] The reactive oligomer is an important component that determines the properties of the adhesive, and forms a polymer bond through a photopolymerization reaction to form a cured coating. Usable reactive oligomers include polyester resins, polyether resins, polyurethane resins, epoxy resins, polyacrylic resins, and silicone resins.

[0121] The reactive monomer functions as a crosslinking agent and a diluent for the reactive oligomer, and influences adhesive properties. Usable reactive monomers include monofunctional monomers, polyfunctional monomers, epoxy-based monomers, vinyl ethers, cyclic ethers, etc.

[0122] The photopolymerization initiator absorbs light energy to generate radicals or cations, thereby initiating photopolymerization, and may be selected to suit the photopolymerizable resin.

[0123] The pressure-sensitive adhesive may be a conventional or later-developed pressure-sensitive adhesive, and in one or more embodiments, may be an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyvinyl alcohol pressure-sensitive adhesive, a polyvinylpyrrolidone pressure-sensitive adhesive, a polyacrylamide pressure-sensitive adhesive, a cellulose pressure-sensitive adhesive, a vinyl alkyl ether pressure-sensitive adhesive, etc. The pressure-sensitive adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but from the viewpoint of availability, etc., it may preferably be an acrylic pressure-sensitive adhesive, which may contain, for example, a (meth)acrylate copolymer, a crosslinking agent, and a solvent.

[0124] The crosslinking agent may be a conventional or later developed crosslinking agent, and may include, for example, a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, or the like, and preferably includes a polyisocyanate compound.

[0125] The solvent may include conventional solvents used in the field of resin compositions, such as alcohol-based compounds such as methanol, ethanol, isopropanol, butanol, and propylene glycol methoxyalcohol; ketone-based compounds such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, and dipropyl ketone; acetate-based compounds such as methyl acetate, ethyl acetate, butyl acetate, and propylene glycol methoxyacetate; cellosolve-based compounds such as methyl cellosolve, ethyl cellosolve, and propyl cellosolve; and hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, and xylene. These may be used alone or in combination of two or more.

[0126] The adhesive layers 120-1 and 120-2 may contain a hot melt adhesive such as an EVA (ethylene vinyl acetate) film or a PVB (polyvinyl butyral) film used in double-sided bonding glass for vehicles, and preferably contain a low-temperature curing PVB (polyvinyl butyral) film contained in the surface protection layer and / or the GPA layer described above.

[0127] The thickness of the adhesive layers 120-1 and 120-2 can be determined appropriately depending on the type of resin acting as the adhesive, the adhesive strength, the environment in which the adhesive is used, etc. In one embodiment, the adhesive layers 120-1 and 120-2 may have a thickness of 0.01 to 1.5 mm, preferably 0.05 to 1.2 mm, and more preferably 0.1 to 1 mm, to ensure sufficient adhesive strength between the surface protection layer 140 and the substrate 130 or between the light control laminate 10 and the substrate 130 and minimize the thickness of the smart window. When a PVB (polyvinyl butyral) film is used as the adhesive layer, the thickness of the PVB film can vary depending on the application and the thickness of the transparent film and / or glass. From a commercial perspective, products with a thickness of 0.38 mm or 0.76 mm can be used.

[0128] In one embodiment, the adhesive layer 120 may be formed on one surface of the substrate (glass) by lamination.

[0129] Lamination step of base materials 130-1 and 130-2 The substrates 130-1 and 130-2 may be one or more selected from glass plates and / or polymer films that are generally transparent and do not impair optical properties, such as polyethylene terephthalate, cyclic olefin polymer, polyethylene naphthalate, polyethersulfone, polycarbonate, cellulose acetate, polymethyl methacrylate, colorless polyimide, glass, and ceramics, with glass being the most preferred.

[0130] Examples of the glass plate include inorganic glass and organic glass. Examples of the inorganic glass include float glass, heat-absorbing glass, heat-reflecting glass, polished glass, patterned glass, wired glass, striped glass, and green glass. The organic glass is synthetic resin glass that can be used in place of inorganic glass. Examples of the organic glass include polycarbonate plates and poly(meth)acrylic resin plates made from synthetic resins. Examples of the poly(meth)acrylic resin plates include polymethyl(meth)acrylate plates.

[0131] The substrate includes not only glass in which an interlayer film is sandwiched between two glass plates, but also glass in which an interlayer film is sandwiched between a glass plate and a PET film or the like, and may also be a glass-resin composite.

[0132] The thickness of the substrate is not particularly limited, but is preferably 1.6 mm or more and 2.1 mm or less.

[0133] The light-controlling laminate may be manufactured by placing an adhesive film and a vehicle glass on both sides of the light-controlling laminate and then using a press, or may be manufactured by coating a resin on one side of the vehicle glass, vacuum bonding the vehicle glass to both sides of the light-controlling laminate, and then UV-curing the resin. 3 or 10 5 The adhesive film may contain a hot-melt adhesive such as OCR or OCA resin. The adhesive film may contain a hot-melt adhesive such as an EVA (ethylene vinyl acetate) film or a PVB (polyvinyl butyral) film, and the materials for the adhesive layer 20 described above, i.e., a photo-curable adhesive, a thermo-curable adhesive, and a pressure-sensitive adhesive, can be used as is, so the description will be omitted. Preferably, a low-temperature curable adhesive may be used in some processes.

[0134] The film laminate may also have a building fixture bonded to one or both sides thereof, or may have a glass for fixture bonded to one side of the film laminate by lamination to produce a smart window product for fixtures, or may have glass for fixtures bonded to both sides of the film laminate after applying a UV adhesive and then UV curing the glass to produce a smart window product for fixtures.

[0135] <Preliminary bonding step (S102)> The pre-bonding step (S102) is a step of melting and bonding each layer of the film laminate by using temperature and vacuum pressure, and is a step of bonding glass and polyvinyl butyral (PVB) film and / or light control laminate to each other. The pre-bonding step of the present invention is performed at 0.1 to 1 bar and may include the steps of S1) raising the temperature to 40 to 90°C, S2) maintaining the temperature of S1), and S3) cooling to 0 to 30°C.

[0136] Specifically, the method may include a step (S1) of raising the temperature to 50 to 70°C at a pressure of preferably 0.1 to 1 bar, more preferably 0.1 to 0.92 bar, a step (S2) of maintaining the temperature at 50 to 70°C, and a step (S3) of cooling to 10 to 20°C.

[0137] <Main joining step (S103)> The main bonding step (S103) is a step of bonding the laminated bodies attached in the preliminary bonding step (S102) while further pressing down any air bubbles that may have formed between them. In the manufacturing method of a smart window, the bonding method of the substrate is one of the important factors that determine the quality of the smart window. When bonding glass to the film laminate, an appropriate bonding method is required that takes into account the elements contained therein. In particular, when using conventional methods on laminates including thin light-control laminates, not only unevenness due to the misalignment of the liquid crystal layer but also haze due to optical distortion may occur. Simply reducing the bonding pressure to prevent this can result in poor bonding.

[0138] Therefore, the present invention provides a method for manufacturing a smart window, which includes at least two or more steps in the main bonding step.

[0139] In an embodiment of the present invention, the permanent bonding process can be performed in two or more stages, gradually applying different pressures to stabilize pressure unevenness that occurs during the bonding process. Specifically, preferably, the permanent bonding process includes the following steps a) and b) to prevent the liquid crystal layer in the film laminate from becoming uneven, thereby producing a smart window with superior quality. In particular, the present invention is characterized by suppressing the liquid crystal polarization phenomenon by performing a primary permanent bonding process at 3.5 to 10 bar in step a) and then performing a secondary permanent bonding process via step b), in which the pressure is reduced to 1 to 3 bar. Compared to conventional permanent bonding processes, which are performed in a single step under high pressure and are prone to liquid crystal polarization, the present invention can eliminate liquid crystal polarization through the secondary bonding process with reduced pressure in step b). However, since performing permanent bonding using only low pressure from the beginning can result in insufficient bonding and difficulty in removing air bubbles, a method of initially performing the bonding process at a high pressure and then reducing the pressure to a low pressure at the end may be more preferable.

[0140] a) Step (S103-1) of maintaining at 3.5 to 10 bar for 15 to 60 minutes In step a), the temperature is controlled in an autoclave and pressure is applied using a compressor, completing the bonding through heating and pressure. Preferably, the temperature is between 50 and 110°C, more preferably between 80 and 100°C. Furthermore, step a) of this bonding process, which is divided into two or more stages, is preferably maintained within the above temperature range in a chamber at 3.5 to 6 bar for 20 to 40 minutes. Specifically, unlike conventional bonding glass, the temperature range is preferably within this range because the light-controlling laminate cannot withstand temperatures up to 140°C, which can lead to discoloration of the polarizing film. Specifically, since the light-controlling laminate contains a liquid crystal-injected layer, it is highly sensitive to pressure. If compressed air outside this range is used, uneven pressure during bonding can lead to liquid crystal misalignment.

[0141] b) Following step a), a step of reducing the pressure to a range of 1 bar to 3 bar and maintaining the pressure for 70 to 100 minutes (S103-2) Following step a), step b) gradually bonds the film by varying the pressure to prevent uneven pressure from being applied to the liquid crystal contained in the film laminate. Specifically, the bonding may be performed at a temperature of preferably 50 to 110°C, more preferably 80 to 100°C. It is also more preferable to reduce the pressure to 1 to 2 bar and maintain the pressure for 80 to 100 minutes. After applying high pressure to remove air bubbles in step a), step b reduces the pressure to eliminate uneven pressure. This has the effect of stabilizing any liquid crystal polarization that may occur in step a), which is performed at a relatively high pressure, through step b).

[0142] In other words, the present invention's bonding method involves a) first bonding with high pressure, and then b) applying low pressure for a long time at the end to eliminate the liquid crystal bias, thereby distributing the liquid crystal contained in the light-control laminate evenly and stably bonding the substrates.In other words, unlike conventional bonding methods, the bonding method is performed in two stages, making it possible to manufacture smart windows with high reliability and significantly reduced liquid crystal unevenness defect rates.

[0143] <<Smart Window>> The present invention includes a smart window manufactured by the above-described method for manufacturing a smart window.

[0144] 2A and 2B are diagrams illustrating a smart window manufactured by a method for manufacturing a smart window according to an embodiment of the present invention. Referring to FIG. 2A, the smart window may be a laminate in the form of a film laminate including a light control laminate 10, a gap layer 150, and a surface protection layer 140, on both sides of which adhesive layers 120-1 and 120-2 and substrates 130-1 and 130-2 are disposed.

[0145] The present invention may also relate to a means of transportation including the smart window, for example, a vehicle in which the smart window is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition, and may include a wearable device and architectural fixtures including the smart window.

[0146] For example, a car including the smart window of the present invention may be manufactured by bonding a substrate (glass) to both sides of a light-control laminate including a polarizing plate, a transparent conductive layer, a liquid crystal layer, and a tacky adhesive layer, for example, by placing an adhesive layer and a substrate (glass) on both sides of the light-control laminate, and then heating the laminate at a temperature of 90°C and approximately 1 bar for 10 to 20 minutes using a press, and the adhesive film may include, but is not limited to, an EVA film, a PVB film, etc. [Example]

[0147] In order to aid in understanding the present invention, experimental examples including specific examples and comparative examples are presented below, but these are merely illustrative of the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications to the examples are possible within the scope and technical spirit of the present invention, and it is natural that such changes and modifications also fall within the scope of the appended claims. Unless otherwise specified, "%" and "parts" in the examples are "% by mass" and "parts by mass", respectively.

[0148] Hereinafter, embodiments of the present invention will be described in more detail. The terms used in this specification are intended to describe the embodiments and are not intended to limit the present invention.

[0149] Manufacturing Example 1: Step of manufacturing a film laminate including a light-control laminate (S100) A 60 μm-thick polyvinyl alcohol film (raw film) (manufactured by Kuraray Co., Ltd., product name "Kuraray Poval Film VF-PE#6000", average polymerization degree 2400, saponification degree 99.9 mol%) was continuously unwound from a raw roll and transported, then immersed in a swelling bath containing pure water at 20°C for 30 seconds. In this swelling process, roll-to-roll stretching (longitudinal uniaxial stretching) was performed by varying the peripheral speed between the nip rolls. The stretching ratio based on the raw film was 2.5 times. The film was then dyed, crosslinked, color-toned, washed, dried, and bonded using conventional techniques to produce a polarizing plate.

[0150] A hard coating layer-forming composition was prepared by mixing 16.2 g of a dendrimer compound (MIWON Specialty Chemicals, SP-1106), 14.4 g of inorganic nanoparticles (10 to 20 nm, silica particles: 50 wt%, solvent: methyl ethyl ketone (MEK)), 1.8 g of a multifunctional (meth)acrylate compound containing an ethylene glycol group, 0.7 g of a photoinitiator (1-hydroxycyclohexylphenyl ketone), and 2.9 g of methyl ethyl ketone on one side of each of the first and second polarizing plates prepared as above. The composition was cured by adjusting the type of Mayer bar and the solid content, and then bar-coated according to the calculated hard coating thickness. The composition was dried at 80°C for 5 minutes and then exposed to a high-pressure mercury lamp at 500 mJ / cm. 2 It hardened with a light intensity of .

[0151] A PEDOT composition was applied to the first and second polarizers and dried at 90°C for 5 to 10 minutes to form a 200 nm-thick transparent conductive layer. This produced a laminate comprising first and second transparent conductive layers made of a conductive polymer (PEDOT) on one side of each polarizer. The PEDOT composition was prepared by mixing coating solution 1 and coating solution 2 in a 1:1 ratio. Coating solution 1 was a mixture of 60 to 65 wt% ethenylbenzenesulfonic acid homopolymer compound with 2,3-dihydrothieno[3,4-b]-1,4-dioxin homopolymer (water-based), 15 to 20 wt% ethyl alcohol, and 20 to 25 wt% deionized water, based on the total weight of the coating solution. Coating solution 2 was a mixture of 0.5 to 1.0 wt% polyester resin (25% solids, water-based), 65 to 75 wt% ethyl alcohol, and 20 to 25 wt% deionized water, based on the total weight of the coating solution.

[0152] An alignment liquid was coated on the surfaces of the first and second transparent conductive layers of each polarizer and dried (80°C / 2 minutes), and then UV was irradiated onto the dried alignment liquid to form first and second alignment films.

[0153] Using a sealant dispenser (SHOTmini 200Ωχ, MUSASHI), sealant (UVF-006, 70,000 mPa·s, SEKISUI) was applied to the manufactured first transparent conductive layer using a sharp needle (SPN-0.25-12.7L) at a discharge pressure of 200 mPa according to the product size drawing, and liquid crystal was injected onto the first alignment film using the ODF process. Then, with the horizontal optical axes of the first and second polarizers aligned parallel to each other at 0° or 90°, the light-control laminate was applied with 3 kg / cm 2 After pressure bonding, UV curing (500 mJ / cm) was performed along the sealant line. 2 ) was performed to produce an optical laminate for smart windows. Then, conductive copper tape (TERAOKA, No. 8323) was adhered to the first transparent conductive layer and the second transparent conductive layer to connect them.

[0154] The surface protection layer is formed by laminating a 0.05 mm thick low-temperature curing polyvinyl butyral (PVB) film (60°C tensile modulus 1.9 x 10) onto the glass substrate. 9 Pa, 90°C tensile modulus 4×10 6 A surface protective layer is prepared by cutting out a film having a melt flow rate (MFR) of 0.02 g / 10 min or less at 140°C (Pa) measured according to ASTM D1238. The thicknesses of the surface protective layer and gap layer of each example, comparative example, and reference example are as shown in Table 2 below.

[0155] The gap layer is a 0.38 mm low-temperature curing polyvinyl butyral (PVB) film (0.38 mm, ISO 9050 standard visible light transmittance (Tv) 88.8% or more, ultraviolet transmittance (Tuv) 0.6% or less, thermal conductivity 0.2 W / mK at 23 to 50°C) and / or a 0.05 mm low-temperature curing polyvinyl butyral (PVB) film (60°C tensile modulus 1.9 x 10 9 Pa, 90°C tensile modulus 4×10 6 An additional layer (having a melt flow rate (MFR) of 0.02 g / 10 min or less at 140°C as measured by ASTM D1238) was laminated to a thickness greater than that of the light-control laminate (0.39 mm thick). The gap layer was cut and placed so that it could surround the entire glass (substrate) excluding the size of the light-control laminate. The thickness and number of gap layers for each example, comparative example, and reference example are as shown in Table 2 below.

[0156] Manufacturing Example 2: Lamination Step (S101) The second substrate (glass), second adhesive layer, film laminate, first adhesive layer, and first substrate (glass) were sequentially laminated on the film laminate prepared according to Preparation Example 1. The first and second adhesive layers were made of 0.38 mm thick low-temperature curing polyvinyl butyral (PVB) film (ISO 9050 standard visible light transmittance (Tv) 88.8% or more, ultraviolet transmittance (Tuv) 0.6% or less, thermal conductivity 0.2 W / mK at 23 to 50°C, specific heat capacity 1.9 KJ / Kg·K at 20°C, 2.3 KJ / Kg·K at 100°C), and the first and second substrates were made of 2.1 T soda lime glass.

[0157] Manufacturing Example 3: Preliminary Bonding Step (S102) The laminated sample was placed in a Resuable Vacuum Rubber Bag (OBRJ-S) and pre-bonded. In Example 1, the pre-bonding step involved placing the laminated smart window in the Vacuum Rubber Bag, raising the temperature from 20°C to 65°C for 15 minutes at a pressure of 0.9 bar, maintaining the temperature at 65°C for 30 minutes, and then lowering the temperature from 65°C to 20°C for 15 minutes. The pressure, temperature, and time conditions for the pre-bonding step in each Example, Comparative Example, and Reference Example were as shown in Table 2 below.

[0158] Manufacturing Example 4: Main joining step (S103) After the preliminary bonding is completed, the final bonding (autoclave) is carried out. In the case of Example 1, the final bonding was carried out under the autoclave conditions of raising the temperature to 90°C under a pressure of 5 bar for 30 minutes, then reducing the pressure to 1.5 bar while maintaining the temperature at 90°C for 90 minutes, after which the final bonding was carried out. The pressure, temperature, and time conditions for the final bonding step in each Example, Comparative Example, and Reference Example are as shown in Table 2 below.

[0159] Examples and Comparative Examples Referring to Preparation Examples 1 to 4, smart windows according to the present invention were manufactured as shown in Table 2 below.

[0160] [Table 2]

[0161] The results of visually inspecting and evaluating the unevenness (LCD unevenness: a general term for the state in which the screen characteristics of a manufactured LCD panel are not uniform) of the smart window manufactured according to Table 2 are shown in Table 3 and Figures 4a to 6d below. Figures 4a to 4f are photographs of the appearance evaluation results of the bonded articles of Examples 1 to 6 of the present invention, taken on a backlight board (light source) using a digital camera. Figures 5a and 5b are photographs of the appearance evaluation results of the bonded articles of Comparative Examples 1 and 2 of the present invention, taken on a backlight board (light source) using a digital camera. Figures 6a to 6d are photographs of the appearance evaluation results of the bonded articles of Reference Examples 1 to 4 of the present invention, taken on a backlight board (light source) using a digital camera.

[0162] [Table 3]

[0163] Referring to Tables 2 and 3 above, it can be seen that when a smart window is manufactured using the manufacturing method of the present invention, no liquid crystal unevenness occurs even after bonding the substrate, and no defective products that cannot be operated due to black spots are produced.

[0164] On the other hand, in the cases of Comparative Examples 1 and 2 in which the manufacturing method of the present invention was not used and the pressure of 5 bar was maintained from the main bonding step onwards, it was confirmed that liquid crystal unevenness occurred.

[0165] Furthermore, in the case of Comparative Example 3, in which the pressure was reduced to 4 bar as step b) in the main bonding step, the pressure was not low enough and there was no step to eliminate the liquid crystal bias, so liquid crystal unevenness occurred even though the main bonding was performed in two steps. [Explanation of symbols]

[0166] 1000:Smart Window 10: Light-controlling laminate 11: First polarizing plate 12: Second polarizing plate 21: First transparent conductive layer 22: Second transparent conductive layer 31: First alignment film 32: Second alignment film 40: Liquid crystal layer 50: Sealant 120-1 and 120-2: First adhesive layer and second adhesive layer 130-1 and 130-2: Substrate 140-1 and 140-2: First surface protective layer and second surface protective layer 150: Gap layer

Claims

1. A step of laminating a film laminate including a light-controlling laminate, an adhesive layer, and a substrate; a pre-bonding step; and This bonding step; The main bonding step includes: a) maintaining at 3.5 to 10 bar for 15 to 60 minutes; and b) after step a), reducing the pressure to 1 bar to 3 bar and maintaining the pressure for 70 to 100 minutes.

2. The method for manufacturing a smart window according to claim 1, wherein steps a) and b) are performed at 50 to 110°C.

3. 2. The method for manufacturing a smart window according to claim 1, wherein the step a) is carried out at 3.5 to 6 bar.

4. The method for manufacturing a smart window according to claim 1, wherein step b) is performed at 1 to 2 bar.

5. The pre-bonding step is carried out at 0.1 to 3 bar, S1) raising the temperature to 40 to 90°C; S2) maintaining the temperature of S1); and 5. The method of claim 1, further comprising the step of: S3) cooling to 0 to 30°C.

6. manufacturing a film stack including the light control stack; The method for manufacturing a smart window according to claim 1 , wherein the step of manufacturing the film stack includes forming a gap layer at an end of the light control stack.

7. The gap layer has a storage modulus G' of 10 ３ or 10 ６ kPa, and the storage modulus G' at 100°C is 5 x 10 ２ or 5 x 10 ３ The method for manufacturing a smart window according to claim 6, further comprising a step of laminating the light-controlling laminate to a thickness that satisfies the above-mentioned tensile strength and a modulus of elasticity of the light-controlling laminate.

8. The method for manufacturing a smart window according to claim 6 , wherein the step of manufacturing the film laminate includes a step of laminating a surface protection layer on at least one of the upper and lower surfaces of the light control laminate.

9. The surface protective layer is a low-temperature curable polyvinyl butyral (PVB) film that cures at a temperature of 90°C or less, and has a tensile modulus E' of 10 at 60°C. ８ or 10 １０ Pa and 10 at 90°C ６ or 10 ７ The method for manufacturing a smart window according to claim 8, wherein the temperature is 1000° C. or less.

10. 10. The method for manufacturing a smart window according to claim 8, wherein the surface protective layer comprises a polyvinyl butyral (PVB) film that does not flow at 100°C or less under a load of 21.6 kg and has a melt flow rate (MFR) of 0.02 g / 10 min or less at 140°C and a load of 2.16 kg as measured according to ASTM D1238.

11. A smart window manufactured by the manufacturing method according to any one of claims 1 to 10, the smart window includes a light control stack; The light-controlling laminate is a first polarizer; a first transparent conductive layer formed on the inner surface of the first polarizer; a second polarizing plate facing the first polarizing plate; a second transparent conductive layer formed on the inner surface of the second polarizer and facing the first transparent conductive layer; a liquid crystal layer disposed between the first transparent conductive layer and the second transparent conductive layer; and an alignment film formed between the transparent conductive layer and the liquid crystal layer, At least one of the first and second transparent conductive layers is formed in direct contact with the first polarizer or the second polarizer.

Images