KR20240131499A - Manufacturing method for optical laminate, optical laminate manufactured by the same, and smart window comprising the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a transmittance variable optical laminate, comprising the steps of forming a transparent conductive layer on one surface of a polarizing film; bonding a carrier substrate including a temperature-sensitive adhesive layer to the back surface of the polarizing film; forming a column spacer on the conductive layer; and peeling off the carrier substrate including the temperature-sensitive adhesive layer; and to an optical laminate manufactured by the manufacturing method and a smart window including the same.

Description

Method for manufacturing an optical laminate, an optical laminate manufactured by the manufacturing method, and a smart window comprising the same {MANUFACTURING METHOD FOR OPTICAL LAMINATE, OPTICAL LAMINATE MANUFACTURED BY THE SAME, AND SMART WINDOW COMPRISING THE SAME}

The present invention relates to a method for manufacturing an optical laminate having variable transmittance, an optical laminate manufactured by the method, and a smart window including the same.

In general, external light blocking coatings are often applied to the windows of vehicles and other means of transportation. However, the windows of conventional means of transportation have fixed transmittance, and the external light blocking coating also has fixed transmittance. Therefore, the windows of such conventional means of transportation have fixed overall transmittance, which may cause accidents. For example, if the overall transmittance is set low, there is no problem during the day when there is sufficient surrounding light, but at night when there is not enough surrounding light, there is a problem that drivers and others may have difficulty properly checking the surroundings of the means of transportation. Alternatively, if the overall transmittance is set high, there is a problem that drivers and others may experience glare during the day when there is sufficient surrounding light. Therefore, a transmittance-variable optical laminate capable of changing the transmittance of light when voltage is applied has been developed.

The above-mentioned variable transmittance optical laminate is driven by varying the transmittance by driving the liquid crystal according to the application of voltage. The variable transmittance optical laminate developed to date is manufactured by forming a conductive layer for driving the liquid crystal on a separate substrate and then combining this with other elements such as a polarizing film.

For example, Japanese Patent Publication No. 2018-010035 also discloses a transmittance variable optical laminate including a transparent electrode layer formed on a polycarbonate (PC) substrate or the like having a predetermined thickness.

However, if a separate substrate is included to form a challenging layer in this way, the manufacturing process becomes complicated, which increases manufacturing costs, increases the thickness of the laminate, and causes a change in transmittance due to a phase difference.

Furthermore, the optical laminate with variable transmittance includes two laminates, and a liquid crystal layer is disposed between the two laminates. In some optical laminates of the past, a column spacer is positioned within the liquid crystal layer in order to maintain a constant gap between the two laminates. However, especially when the optical laminate with variable transmittance is implemented in a flexible form, a polarizing film having flexible performance is included instead of glass. In this case, there is a problem in that the polarizing film is deformed due to heat treatment during the process of forming the column spacer.

Accordingly, there is a need for development of a transmittance variable optical laminate that can simplify the manufacturing process and reduce the thickness by not including a separate substrate for forming a challenging layer, while preventing cracks, scratches, and deformation of polarizing films that may occur during the process.

Japanese Publication Patent No. 2018-010035

The purpose of the present invention is to provide a method for manufacturing a transmittance variable optical laminate, which can be applied to existing manufacturing facilities and exhibits flexible unique characteristics while preventing defects due to deformation of a polarizing film caused by heat treatment during a column spacer forming process.

In addition, the present invention aims to provide a method for manufacturing a transmittance variable optical laminate with a simplified manufacturing process by not including a separate substrate for forming a conductive layer.

In addition, the present invention aims to provide a method for manufacturing a variable transmittance optical laminate having a significantly reduced thickness by not including a separate substrate for forming a conductive layer.

In addition, the present invention aims to provide a method for manufacturing a variable transmittance optical laminate having improved transmittance in a light-transmitting mode by not including a separate substrate for forming a conductive layer.

In addition, the present invention aims to provide a transmittance variable optical laminate manufactured by the method for manufacturing the above-mentioned transmittance variable optical laminate.

In addition, an object of the present invention is to provide a smart window including the above-described variable transmittance optical laminate.

However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The present invention relates to a method for manufacturing a transmittance variable optical laminate, comprising: a step of forming a transparent conductive layer on one surface of a polarizing film; a step of bonding a carrier substrate including a temperature-sensitive adhesive layer to the back surface of the polarizing film; a step of forming a column spacer on the transparent conductive layer; and a step of peeling off the carrier substrate including the temperature-sensitive adhesive layer.

In the first aspect of the present invention, the temperature-sensitive adhesive layer may have an adhesive strength on a surface in contact with the polarizing film of 1.0 N/25 mm to 2.0 N/25 mm at 25 to 50°C and 0.05 N/25 mm or less at -40 to 0°C, based on a polyimide film, when measured in accordance with JIS Z0237 (180° peeling).

In the second aspect of the present invention, the temperature-sensitive adhesive layer may be formed from a temperature-sensitive adhesive including a release film on both sides, and the temperature-sensitive adhesive may have different adhesive strengths from the release films on both sides.

In the third aspect of the present invention, the step of forming the column spacer may include the step of applying a photosensitive resin composition on the conductive layer and performing a heat treatment.

In the fourth aspect of the present invention, the step of peeling off the carrier substrate may be peeling off the transmittance variable optical laminate on which the column spacer is formed at 0°C or lower.

In the fifth aspect of the present invention, the transparent conductive layer may be formed in direct contact with the polarizing film without including a separate substrate therebetween.

In the sixth aspect of the present invention, the transparent conductive layer may be formed by directly contacting the polarizing film, including an adhesive-friendly layer.

In the seventh aspect of the present invention, the transparent conductive layer may include at least one selected from the group consisting of a transparent conductive oxide, a metal, a carbon-based material, a conductive polymer, a conductive ink, and nanowires.

In addition, the present invention relates to a transmittance variable optical laminate manufactured by the method for manufacturing the above-mentioned transmittance variable optical laminate.

The variable transmittance optical laminate of the present invention may further include at least one selected from the group consisting of an adhesive layer, an alignment film, an ultraviolet absorbing layer, and a hard coating layer.

The variable transmittance optical laminate of the present invention comprises: a polarizing film; a transparent conductive layer formed on one surface of the polarizing film; a column spacer formed on the transparent conductive layer; and a carrier substrate adhered to the back surface of the polarizing film via a temperature-sensitive adhesive layer, wherein the carrier substrate may be removed after forming the column spacer.

In addition, the present invention relates to a smart window including the above-described variable transmittance optical laminate.

According to the method for manufacturing a variable transmittance optical laminate according to the present invention, even if the optical laminate is manufactured using existing manufacturing equipment, occurrence of defects due to deformation of the polarizing film by heat treatment during the column spacer forming process can be prevented.

In addition, according to the method for manufacturing a variable transmittance optical laminate according to the present invention, the process of forming a conductive layer on a substrate and bonding it with another member for forming a conventional optical laminate can be omitted, so that the manufacturing process can be simplified compared to the conventional optical laminate.

In addition, according to the method for manufacturing a variable transmittance optical laminate according to the present invention, a conductive layer is formed directly on one surface of a polarizing film, so that a separate substrate for forming the conductive layer is not included, and thus the thickness can be significantly reduced compared to a conventional optical laminate.

In addition, according to the method for manufacturing a variable transmittance optical laminate according to the present invention, a conductive layer is formed directly on one surface of a polarizing film, so that a separate substrate for forming the conductive layer is not included, and thus the transmittance in the light transmission mode can be improved compared to a conventional optical laminate.

Figure 1 is a flow chart showing the process sequence for manufacturing a variable transmittance optical laminate according to one embodiment of the present invention.
FIG. 2 is a diagram illustrating a method for manufacturing a variable transmittance optical laminate according to an embodiment of the present invention step by step according to the process sequence.
Figure 3 is a diagram showing a supply form of a temperature-sensitive adhesive applied to one embodiment of the present invention.
FIG. 4 is a diagram showing the laminated structure of a transmittance variable optical laminate manufactured by a method for manufacturing a transmittance variable optical laminate according to another embodiment of the present invention.
FIGS. 5 and 6 are diagrams showing a laminated structure of a smart window according to one or more embodiments of the present invention.

The present invention relates to a method for manufacturing an optical laminate with variable transmittance using a flexible polarizing film, and more particularly, to a method for manufacturing an optical laminate with variable transmittance, which can be applied to existing manufacturing facilities while preventing defects during the manufacturing process so as to exhibit the unique characteristics of a smart window, by forming a transparent conductive layer on one surface of a polarizing film, bonding a carrier substrate including a temperature-sensitive adhesive layer to the reverse surface, forming a column spacer on the transparent conductive layer, and then peeling off the carrier substrate including the temperature-sensitive adhesive layer.

More specifically, the present invention relates to a method for manufacturing a transmittance variable optical laminate, comprising: a step of forming a transparent conductive layer on one side of a polarizing film; a step of bonding a carrier substrate including a temperature-sensitive adhesive layer to the back side of the polarizing film; a step of forming a column spacer on the conductive layer; and a step of peeling off the carrier substrate including the temperature-sensitive adhesive layer.

A transmittance variable optical laminate manufactured by the method for manufacturing a transmittance variable optical laminate of the present invention is particularly suitable for a technical field in which the transmittance of light can be changed according to the application of voltage, and can be used, for example, in smart windows.

A smart window is an optical structure that controls the amount of light or heat that passes through by changing the light transmittance according to the application of an electrical signal. In other words, a smart window is provided so that it can be changed to a transparent, opaque, or translucent state by voltage, and is also called variable transmittance glass, dimming glass, or smart glass.

Smart windows can be used as partitions for dividing the interior space of vehicles and buildings or for privacy, or as skylights placed in openings of buildings, and can also be used as highway signs, bulletin boards, scoreboards, clocks or advertising screens, and can be used to replace glass in transportation means such as windows or sunroofs of cars, buses, airplanes, ships or trains.

The optical laminate with variable transmittance of the present invention can also be utilized as a smart window in the various technical fields described above, but since the conductive layer is formed directly on the polarizing film, it does not include a separate substrate for forming the conductive layer, so it is thin and has advantageous bending characteristics, and can be particularly suitably used as a smart window for vehicles or buildings. In one or more embodiments, the smart window to which the optical laminate with variable transmittance of the present invention is applied can be used for front windows, rear windows, side windows, and sunroof windows of vehicles, or windows for buildings, and in addition to the purpose of blocking external light, it can also be used for partitioning internal spaces of vehicles or buildings, such as interior partitions, or for protecting privacy.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the contents of the invention described above, serve to further understand the technical idea of the present invention, so the present invention should not be interpreted as being limited to matters described in such drawings.

The terms used in this specification are for the purpose of describing embodiments only and are not intended to limit the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase.

As used herein, the terms “comprises” and/or “comprising” are used to mean that they do not exclude the presence or addition of one or more other components, steps, operations, and/or elements other than the components, steps, operations, and/or elements mentioned. Like reference numerals refer to like elements throughout the specification.

Spatially relative terms such as "below," "bottom," "lower," "above," "top," and "upper" can be used to easily describe the relationship between one element or component and other elements or components, as illustrated in the drawings. It should be understood that spatially relative terms include different orientations of the elements during use or operation in addition to the orientations illustrated in the drawings. For example, if an element illustrated in the drawings is flipped, an element described as "below" or "lower" of another element can be placed "above" the other element. Thus, the exemplary term "below" can include both the above and below directions. The elements can also be oriented in other directions, and thus spatially relative terms can be interpreted according to the orientation.

As used herein, “plane direction” can be interpreted as a direction orthogonal to the polarizing film and/or transparent conductive layer, i.e., the direction viewed from the user’s viewing side.

<Method for manufacturing optical laminate with variable transmittance>

FIG. 1 is a flow chart showing the process sequence for a method for manufacturing a variable transmittance optical laminate according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the process sequence for a method for manufacturing a variable transmittance optical laminate according to an embodiment of the present invention step by step.

Referring to FIGS. 1 and 2, a method for manufacturing a transmittance variable optical laminate according to an embodiment of the present invention relates to a method for manufacturing a transmittance variable optical laminate, including the steps of: forming a transparent conductive layer (200) on one surface of a polarizing film (100) (S101); bonding a carrier substrate (400) including a temperature-sensitive adhesive layer (300) to the back surface of the polarizing film (100) (S102); forming a column spacer (500) on the transparent conductive layer (200) (S103); and peeling off the carrier substrate (400) including the temperature-sensitive adhesive layer (300) (S104).

A method for manufacturing a variable transmittance optical laminate according to one embodiment of the present invention includes a step (S101) of first preparing a polarizing film (100) and forming a transparent conductive layer (200) on one surface thereof.

The polarizing film (100) includes a polarizer, and may include a stretchable polarizer or may be provided as a stretchable polarizing film. In one embodiment, the stretchable polarizer may include a stretched polyvinyl alcohol (PVA)-based resin. The polyvinyl alcohol (PVA)-based resin may be a polyvinyl alcohol-based resin obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, examples thereof include copolymers of vinyl acetate and other monomers copolymerizable therewith. The other monomers may include unsaturated carboxylic acid-based, unsaturated sulfonic acid-based, olefin-based, vinyl ether-based, and acrylamide-based monomers having an ammonium group. Additionally, polyvinyl alcohol (PVA) resins may be modified, such as polyvinyl formal or polyvinyl acetal modified with aldehydes.

In addition, the polarizing film (100) may include a coated polarizer. In one embodiment, the coated polarizer may be formed by a liquid crystal coating composition, and may be formed, for example, by applying the liquid crystal coating composition onto the upper surface of the protective layer. At this time, the liquid crystal coating composition may include a reactive liquid crystal compound and a dichroic dye.

The above reactive liquid crystal compound may include a reactive mesogen (RM) capable of expressing liquid crystal properties, and/or a monomer molecule including a polymerizable terminal functional group and having a liquid crystal phase after a crosslinking reaction by heat or light. When the above reactive liquid crystal compound is polymerized by light or heat, a polymer network can be formed while maintaining the liquid crystal arrangement. By utilizing the above reactive liquid crystal compound, a thin film polarizer with improved mechanical and thermal stability can be formed while maintaining the optical anisotropy or dielectric constant characteristics of the liquid crystal.

The above dichroic dye is a component that is included in a liquid crystal coating composition to impart polarization properties, and has properties in which the absorbance in the long-axis direction of the molecule and the absorbance in the short-axis direction are different. The above dichroic dye may be a dichroic dye that has been developed in the past or will be developed in the future, and may include, for example, an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, an anthraquinone dye, and the like, and these may be used alone or in combination.

The above liquid crystal coating composition may further include a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye, and examples thereof include propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, and chloroform. In addition, the liquid crystal coating composition may further include a leveling agent, a polymerization initiator, and the like, within a range that does not impair the polarization characteristics of the coating film.

When the above two polarizing films (100) are laminated on both sides of the liquid crystal layer, it is preferable that the transmission axes of each polarizing film (100) are arranged perpendicular to each other in the plane direction. In this case, there may be an advantage in improving the transmittance variable range between the light-transmitting mode and the light-blocking mode of the optical laminate according to the liquid crystal driving.

In one or more embodiments, the polarizing film (100) may further include one or more functional layers selected from the group consisting of a protective layer, a phase difference control layer, and a refractive index control layer.

The above protective layer is intended to protect the polarization characteristics of the polarizing film (100) from post-processing and external environments, and can be implemented in the form of a protective film, etc.

The above protective layer may also be used as a multi-layer structure in which one or more protective layers are continuously laminated, and may also be used in combination with other functional layers.

In one or more embodiments, the protective layer may include at least one selected from the group consisting of polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), diacetyl cellulose, triacetyl cellulose (TAC), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyethyl acrylate (PEA), polyethyl methacrylate (PEMA), and cyclic olefin polymer (COP). there is.

The above-mentioned phase difference control layer is intended to complement the optical characteristics of the optical laminate, and can be implemented in the form of a phase difference film, etc., and can use a phase difference film, etc. that is conventional or developed in the future. For example, a quarter-wave plate (1/4 wave plate) or a half-wave plate (1/2 wave plate) for delaying the phase of light can be used, and these can be used alone or in combination.

The above phase difference control layer may be used alone or in combination with other functional layers.

The above-mentioned phase difference control layer can use a polymer film or a liquid crystal polymer film that is stretched in an appropriate manner to impart optical anisotropy through stretching.

In one embodiment, the polymer stretched film may use a polymer layer including a polyolefin such as polyethylene (PE) or polypropylene (PP), a cyclo olefin polymer (COP) such as polynorbornene, a polyester such as polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), an acrylic resin, polycarbonate (PC), or polyethylene terephthalate (PET), a cellulose ester polymer such as polyacrylate, polyvinyl alcohol (PVA), or triacetyl cellulose (TAC), or a copolymer of two or more monomers among the monomers forming the polymer.

The method for obtaining the above polymer stretched film is not particularly limited, and for example, the polymer material may be formed into a film and then stretched. The method for forming into the film form is not particularly limited, and it is possible to form the film by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, extrusion molding, foam molding, and cast molding, and secondary processing molding methods such as pressure molding and vacuum molding can also be used. Among these, extrusion molding and cast molding are preferably used. At this time, for example, an extruder equipped with a T-die, a circular die, etc. can be used to extrusion mold an unstretched film. When obtaining a molded product by extrusion molding, a material in which various resin components, additives, etc. are melt-mixed in advance can be used, and it can also be molded by melt-mixing during extrusion molding. In addition, a solvent common to various resin components, such as chloroform or dimethylene chloride, can be used to dissolve various resin components, and then cast and dry and solidify to cast an unstretched film.

The above polymer stretched film can be stretched uniaxially in the mechanical direction (MD; mechanical direction, longitudinal direction or length direction) of the formed film, uniaxially in the direction perpendicular to the mechanical direction (TD; transverse direction, transverse direction or width direction), and can also be manufactured into a biaxially stretched film by stretching by a sequential biaxial stretching method of roll stretching and tenter stretching, a simultaneous biaxial stretching method by tenter stretching, a biaxial stretching method by tubular stretching, etc.

The above liquid crystal polymerization film may contain a reactive liquid crystal compound in a polymerized state. The reactive liquid crystal compound may be applied in the same manner as the reactive liquid crystal compound of the above-described coated polarizer.

In one or more embodiments, the thickness of the phase difference control layer may be 10 µm to 100 µm in the case of a polymer stretched film, and 0.1 µm to 5 µm in the case of a liquid crystal polymer film.

The above refractive index control layer is provided to compensate for the refractive index difference of the optical laminate due to the transparent conductive layer (200), and may serve to improve visibility characteristics, etc. by reducing the refractive index difference. In addition, the refractive index control layer may be provided to correct the color caused by the transparent conductive layer (200). Meanwhile, when the transparent conductive layer has a pattern, the difference in transmittance between the pattern area where the pattern is formed and the non-pattern area where the pattern is not formed can be compensated for through the refractive index control layer.

Specifically, the transparent conductive layer (200) is laminated adjacent to another member having a different refractive index, and a difference in light transmittance may be induced due to a difference in refractive index with respect to the adjacent layer. In particular, when a pattern is formed on the transparent conductive layer, a problem may occur in which a pattern area and a non-pattern area are distinguished and recognized. Therefore, by including the refractive index control layer, the difference in light transmittance of the optical laminate can be reduced by compensating for the refractive index. In particular, when a pattern is formed on the transparent conductive layer (200), the pattern area and the non-pattern area are not distinguished and recognized.

In one embodiment, the refractive index of the refractive index control layer may be appropriately selected depending on the material of the adjacent other member, but is preferably 1.4 to 2.6, and more preferably 1.4 to 2.4. In this case, light loss due to a sharp difference in refractive index between the other member and the transparent conductive layer (200) can be prevented.

The above refractive index control layer is not particularly limited as long as it can prevent a sharp difference in refractive index between other elements and the transparent conductive layer (200), and a compound used in the formation of a refractive index control layer that is conventionally or later developed can be used, and for example, it can be formed from a refractive index control layer forming composition containing a polymerizable isocyanurate compound.

In one embodiment, the polarizing film (100) may further include, in addition to the functional layer described above, another functional layer to assist or enhance the characteristics of the polarizing film, and for example, may further include an overcoat layer, etc. to further enhance mechanical durability.

In one or more embodiments, the polarizing film (100) may have a thickness of 30 to 300 μm, preferably 30 to 200 μm, and more preferably 50 to 150 μm. In this case, the polarizing film (100) can be used to manufacture a thin optical laminate while maintaining optical properties.

The present invention can form a transparent conductive layer (200) on one surface of the polarizing film (100).

The above transparent conductive layer (200) is provided for driving the liquid crystal layer. For example, as shown in FIG. 2, the transparent conductive layer (200) may be formed in direct contact with the polarizing film (100).

Conventionally, optical laminates used in the manufacture of smart windows and the like have been manufactured by forming a conductive layer for driving liquid crystals on one surface of a substrate and bonding the other surface of the substrate with a polarizing film. However, the optical laminate with variable transmittance according to the present invention is characterized in that the thickness of the laminate is reduced while the transmittance and bending characteristics in the light transmission mode are improved by directly forming the conductive layer on one surface of a polarizing film without including a separate substrate for forming the conductive layer.

In one embodiment, the transparent conductive layer (200) may be formed by being directly deposited on the polarizing film (100). At this time, the transparent conductive layer (200) may be formed by performing a pretreatment such as corona treatment or plasma treatment on one side of the polarizing film (100) to improve adhesion to the polarizing film (100), and then directly contacting the side on which the pretreatment was performed. The pretreatment is not limited to corona treatment or plasma treatment, and any pretreatment process that is conventionally or later developed may be used within a range that does not harm the purpose of the present invention.

In another embodiment, the transparent conductive layer (200) may be formed in direct contact with the polarizing film (100) with an adhesive-friendly layer (not shown) provided on one side of the polarizing film (100) interposed therebetween to improve adhesion to the polarizing film (100).

The above transparent conductive layer (200) preferably has a visible light transmittance of 50% or more, and may include, for example, at least one selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires, but is not limited thereto, and any material of a transparent conductive layer developed in the past or later may be used.

In one or more embodiments, the transparent conductive oxide may include at least one 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), and zinc oxide (ZnO). In addition, the metal may include at least one 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, and may include, for example, a silver-palladium-copper (APC) alloy or a copper-calcium (CuCa) alloy. The above carbon-based material may include at least one selected from the group consisting of carbon nanotubes (CNTs) and graphene, and the conductive polymer may include at least one selected from the group consisting of polypyrrole, polythiophene, polyacetylene, PEDOT, and polyaniline. The conductive ink may be an ink in which a metal powder and a curable polymer binder are mixed, and the nanowire may be, for example, a silver nanowire (AgNW).

In addition, the transparent conductive layer (200) may be formed into a two-layer or more structure by combining the above materials. For example, it may be formed into a two-layer structure including a metal layer and a transparent conductive oxide layer to lower the reflectivity of incident light and increase the transmittance.

The above transparent conductive layer (200) can be formed by a method commonly used in the field, and for example, can be formed by selecting an appropriate process from among coating processes such as a spin coating method, a roller coating method, a bar coating method, a dip coating method, a gravure coating method, a curtain coating method, a die coating method, a spray coating method, a doctor coating method, and a kneader coating method; printing processes such as a screen printing method, a spray printing method, an inkjet printing method, a lithographic printing method, a plate printing method, and a flat printing method; and a deposition process such as a CVD (chemical vapor deposition), a PVD (physical vapor deposition), and a PECVD (plasma enhanced chemical vapor deposition).

A method for manufacturing a variable transmittance optical laminate according to one embodiment of the present invention includes a step (S102) of bonding a carrier substrate (400) including a temperature-sensitive adhesive layer (300) to the back surface of the polarizing film (100) on which a transparent conductive layer (200) is not formed.

The above temperature-sensitive adhesive layer (300) is formed on one surface of the carrier substrate (400), and there is no particular limitation on the method of forming the temperature-sensitive adhesive layer (300). For example, the temperature-sensitive adhesive may be formed by applying the temperature-sensitive adhesive, or the temperature-sensitive adhesive may be prepared in a film form and bonded.

The above temperature-sensitive adhesive refers to an adhesive whose adhesive strength changes in response to temperature change, and FIG. 3 is a drawing showing a supply form of a temperature-sensitive adhesive according to one embodiment of the present invention.

When the temperature-sensitive adhesive (20) is prepared in a film form to form the temperature-sensitive adhesive layer (300), the temperature-sensitive adhesive (20) may be an adhesive that includes a release film (10, 30) on both sides. In this case, it is preferable that the temperature-sensitive adhesive (20) has different adhesive strengths with respect to the release films (10, 30) on both sides. Since the adhesive strengths of the temperature-sensitive adhesive (20) and the release films (10, 30) on both sides are different from each other, when the release film (10) on one side of the temperature-sensitive adhesive (20) is removed, the release film (30) on the other side is not removed, and when the temperature-sensitive adhesive (20) from which the release film (10) on one side has been removed is first adhered to one side of the carrier substrate (400), and then the release film (30) on the other side is removed, the adhesive surface adhered to the carrier substrate (400) does not come off.

The above temperature-sensitive adhesive layer (300) is characterized in that the adhesive strength of the surface in contact with the polarizing film is, when measured in accordance with JIS Z0237 (180° peeling), 1.0 N/25 mm to 2.0 N/25 mm at 25 to 50°C and 0.05 N/25 mm or less at -40 to 0°C based on the polyimide film. In particular, the characteristic of 0.05 N/25 mm or less at -40 to 0°C is a very low value that is outside the reliable range by a general peeling force measurement method, so that the polarizing film can be easily peeled at -40 to 0°C without damage.

The temperature-sensitive adhesive for forming the above-mentioned temperature-sensitive adhesive layer (300) may include a side chain crystalline polymer, a crosslinking agent, and an antistatic agent, and the antistatic agent may include an ionic liquid having a melting point of 0° C. or lower. The desired temperature-sensitive adhesive can be manufactured by appropriately adjusting the content of the above-mentioned components.

Meanwhile, the carrier substrate (400) may include glass having a thickness of 0.5 to 1T to prevent the polarizing film (100) from being deformed even when high-temperature heat treatment is involved in the process, and to facilitate the process and movement. The carrier substrate (400) may be made of tempered glass, preferably tempered glass.

A method for manufacturing a variable transmittance optical laminate according to one embodiment of the present invention includes a step (S103) of forming a column spacer (500) on the transparent conductive layer (200) formed on one surface of the polarizing film (100).

The above column spacer (500) serves to maintain a constant liquid crystal cell gap and can be formed on the transparent conductive layer (200).

The above column spacer (500) includes a step of applying a photosensitive resin composition onto the transparent conductive layer (200) and performing a heat treatment, and thereby forming a coating film, and then exposing and developing it to form a column spacer (500) pattern.

The above coating method is not particularly limited, and may be carried out by a coating method or a printing process such as roll coating, spin coating, slit coating, inkjet printing, etc.

The above heat treatment can be performed at 50 to 100°C, and even after undergoing this heat treatment process, the polarizing film (100) is adhered to the carrier substrate (400), and the carrier substrate (400) and the temperature-sensitive adhesive layer (300) have heat resistance to the heat treatment temperature during the process, so that deformation such as shrinkage, expansion, and deterioration of the polarizing film (100) due to the heat treatment can be minimized.

Therefore, even if a material with somewhat insufficient heat resistance is included in order to provide a smart window, the manufacturing method of the present invention enables stable formation of a column spacer even if the heat treatment as described above is performed, and deformation of the smart window does not occur.

The photosensitive resin composition for the above column spacer (500) may include a binder resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent.

The above binder resin is a component that provides solubility in an alkaline developer used in a development process, and can be used without limitation as long as it is soluble in an alkaline developer. The binder resin has solubility in an alkaline developer used in a development process when forming a pattern, and in order to improve low-temperature curing characteristics, the binder resin can be manufactured by copolymerizing an ethylenically unsaturated monomer having a carboxyl group, or by polymerizing an ethylenically unsaturated monomer having a carboxyl group and a copolymerizable unsaturated monomer.

Specific examples of the ethylenically unsaturated monomer having the above carboxyl group include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as fumaric acid, mesaconic acid, and itaconic acid; and anhydrides of the above dicarboxylic acids; and mono(meth)acrylates of polymers having a carboxyl group and a hydroxyl group at both terminals such as ω-carboxypolycaprolactone mono(meth)acrylate, and acrylic acid and methacrylic acid are preferable.

Specific examples of the above copolymerizable unsaturated polymerizable monomers include:

Glycidyl methacrylate, an unsaturated monomer having a glycidyl group;

Ethylenically unsaturated monomers having a hydroxyl group, such as hydroxyethyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and N-hydroxyethyl acrylamide;

Aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, p-chlorostyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-vinylbenzyl methyl ether, m-vinylbenzyl methyl ether, p-vinylbenzyl methyl ether, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, and p-vinylbenzyl glycidyl ether;

N-substituted maleimide compounds such as N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, N-o-hydroxyphenylmaleimide, N-m-hydroxyphenylmaleimide, N-p-hydroxyphenylmaleimide, N-o-methylphenylmaleimide, N-m-methylphenylmaleimide, N-p-methylphenylmaleimide, N-o-methoxyphenylmaleimide, N-m-methoxyphenylmaleimide, and N-p-methoxyphenylmaleimide;

Alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, sec-butyl (meth)acrylate, and t-butyl (meth)acrylate; Alicyclic (meth)acrylates such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclo[5.2.1.0 2,6 ]decan-8-yl (meth)acrylate, 2-dicyclopentanyloxyethyl (meth)acrylate, and isobornyl (meth)acrylate;

Aryl (meth)acrylates such as phenyl (meth)acrylate and benzyl (meth)acrylate;

Unsaturated oxetane compounds such as 3-(methacryloyloxymethyl)oxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-2-trifluoromethyloxetane, 3-(methacryloyloxymethyl)-2-phenyloxetane, 2-(methacryloyloxymethyl)oxetane, and 2-(methacryloyloxymethyl)-4-trifluoromethyloxetane; but are not limited thereto.

As polymerizable monomers having unsaturated bonds capable of copolymerization, glycidyl methacrylate and tetrahydrofuryl methacrylate, which are unsaturated monomers having a glycidyl group, are preferable.

Each of the above copolymerizable unsaturated monomers can be used alone or in combination of two or more.

The content of the above binder resin is comprised in an amount of 3 to 40 wt%, preferably 3 to 20 wt%, based on the total weight of the photosensitive resin composition. When the content of the above binder resin is within the above range, the solubility in the developer is sufficient, facilitating pattern formation, and preventing film reduction in the pixel portion of the exposed portion during development, thereby improving the omission property of the non-pixel portion, which is preferable.

In addition, in order to secure the developability of the photosensitive resin composition, the acid value of the binder resin is preferably 30 to 150 mgKOH/g. If the acid value of the binder resin is less than 30 mgKOH/g, it is difficult for the photosensitive resin composition to secure a sufficient developing speed, and if it exceeds 150 mgKOH/g, the adhesion with the substrate is reduced, making it easy for pattern short-circuiting to occur.

The above photopolymerizable compound is a compound that can be polymerized by the action of the following photopolymerization initiator, and a monofunctional monomer, a difunctional monomer or a polyfunctional monomer can be used, and it is preferable to use a polyfunctional monomer having two or more functions.

Specific examples of the above monofunctional monomers include, but are not limited to, nonylphenylcarbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexylcarbitol acrylate, 2-hydroxyethyl acrylate, or N-vinylpyrrolidone.

Specific examples of the above bifunctional monomers include, but are not limited to, 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, bis(acryloyloxyethyl)ether of bisphenol A, or 3-methylpentanediol di(meth)acrylate.

Specific examples of the above multifunctional monomers include, but are not limited to, trimethylol propane tri(meth)acrylate, ethoxylated trimethylol propane tri(meth)acrylate, propoxylated trimethylol propane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexaacrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, propoxylated dipentaerythritol hexa(meth)acrylate, or dipentaerythritol hexa(meth)acrylate.

In addition, the photopolymerizable compound may be included in an amount of 5 to 50 wt% based on the total weight of the photosensitive resin composition, preferably 7 to 45 wt%, and more preferably 10 to 20 wt%. When the photopolymerizable compound is included within the above range, the strength and smoothness of the spacer are improved, which is preferable.

The above photopolymerization initiator is a compound that generates radicals capable of initiating polymerization of the photopolymerizable compound upon exposure to radiation such as visible light, ultraviolet light, ultraviolet light, electron beams, or X-rays.

The above photopolymerization initiator contains an oxime ester photopolymerization initiator as an essential component.

Examples of the above oxime ester compounds include 2-O-benzoyloxime-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime), etc. Examples of commercially available oxime ester photopolymerization initiators include BASF's Irgacure® OXE 01, Irgacure® OXE 02, and Irgacure® OXE 03, etc. Since each has a different absorbance and generated radical species, it is preferable to use two or more types in combination.

In addition, a photopolymerization initiator other than an oxime ester-based photopolymerization initiator may be additionally used in combination. Representative examples thereof include at least one compound selected from the group consisting of acetophenone-based compounds, benzophenone-based compounds, triazine-based compounds, biimidazole-based compounds, and thioxanthone-based compounds.

Specific examples of the above acetophenone compounds include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one, etc.

Examples of the above benzophenone compounds include benzophenone, 0-benzoylbenzoate methyl, 4-[0107] phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, etc.

Specific examples of the above triazine compounds include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-piperonyl-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, Examples thereof include 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine, etc.

Specific examples of the above biimidazole compounds include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(alkoxyphenyl)biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(trialkoxyphenyl)biimidazole, 2,2-bis(2,6-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, or imidazole compounds in which the phenyl group at the 4,4',5,5' position is substituted by a carboalkoxy group. Among these, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, and 2,2-bis(2,6-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole are preferably used.

Examples of the above thioxanthone compounds include 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, etc.

In addition, the photopolymerization initiator may further include a photopolymerization initiation assistant in order to improve the sensitivity of the infrared transmitting photosensitive resin composition. The infrared transmitting photosensitive resin composition according to the present invention can further improve the sensitivity by containing the photopolymerization initiation assistant, thereby improving the productivity.

As the photopolymerization initiation assistant, for example, at least one compound selected from the group consisting of an amine compound, a carboxylic acid compound, and a multifunctional thiol compound having a thiol group can be preferably used.

As the above amine compound, it is preferable to use an aromatic amine compound, and specifically, aliphatic amine compounds such as triethanolamine, methyldiethanolamine, and triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethylparatoluidine, 4,4'-bis(dimethylamino)benzophenone (commonly known as Michler's ketone), 4,4'-bis(diethylamino)benzophenone, and the like can be used.

The above carboxylic acid compound is preferably an aromatic heteroacetic acid, and specific examples thereof include phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, methoxyphenylthioacetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, naphthoxyacetic acid, and the like.

Examples of the polyfunctional thiol compounds having the above thiol group include 2-mercaptobenzothiazole, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), etc.

In addition, the photopolymerization initiator may further include a photopolymerization initiation assistant to improve the sensitivity of the photosensitive resin composition. By containing the photopolymerization initiation assistant, the photosensitive resin composition can further increase the sensitivity and improve productivity.

The photopolymerization initiation assistant may preferably be one or more compounds selected from the group consisting of, for example, amine compounds, carboxylic acid compounds, and multifunctional thiol compounds.

As the above amine compound, it is preferable to use an aromatic amine compound, and specifically, aliphatic amine compounds such as triethanolamine, methyldiethanolamine, and triisopropanolamine, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethylparatoluidine, 4,4'-bis(dimethylamino)benzophenone (commonly known as Michler's ketone), 4,4'-bis(diethylamino)benzophenone, and the like can be used.

The above carboxylic acid compound is preferably an aromatic heteroacetic acid, and specific examples thereof include phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, methoxyphenylthioacetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, naphthoxyacetic acid, and the like.

The polyfunctional thiol compounds include Tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, Trimethylolpropane tris -3-mercaptopropionate), Pentaerythritol tetrakis-3-mercaptopropionate), and Dipentaerythritol hexa-3-mercaptopropionate).

The photopolymerization initiator may be included in an amount of 1 to 20 wt%, preferably 1 to 10 wt%, based on the total weight of the photosensitive resin composition. When the photopolymerization initiator is within the above-described range, the photosensitive resin composition becomes highly sensitive, so that the exposure time is shortened, thereby improving productivity, which is preferable. In addition, the strength of the spacer formed using the composition under the above-described conditions and the smoothness on the surface of the spacer may be improved. In addition, in the case of the oxime ester-based photopolymerization initiator, it should be included in an amount of 10 to 100 wt%, preferably 20 to 100 wt%, of the total photopolymerization initiator. When the proportion of the oxime ester-based photopolymerization initiator in the total photopolymerization initiator is less than 10 wt%, the decrease in sensitivity due to the dye cannot be overcome, and pattern short-circuiting is likely to occur during the developing process.

In addition, when the photopolymerization initiation auxiliary agent is further used, the photopolymerization initiation auxiliary agent may be included in an amount of 0.1 to 40 parts by weight, preferably 1 to 30 parts by weight, based on the solid content, per 100 parts by weight of the total of the binder resin and the photopolymerizable compound. When the amount of the photopolymerization initiation auxiliary agent used is within the range of 0.1 to 40 parts by weight described above, the sensitivity of the photosensitive resin composition is further increased, and the productivity of the spacer formed using the composition is improved.

The solvent used in the above binder resin may be any solvent effective in dissolving other components included in the photosensitive resin composition, but an organic solvent having a boiling point of 100°C to 200°C is preferable in terms of applicability and drying property. More preferably, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, ethyl lactate, butalactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, etc. can be used, and further, a solvent of propylene glycol monomethyl ether acetate and/or 4-hydroxy-4-methyl-2-pentanone is preferable.

It is possible to additionally use a solvent used in a conventional photosensitive resin composition that is effective in dissolving other components included in the photosensitive resin composition together with the above solvent. In particular, ethers, aromatic hydrocarbons, ketones, alcohols, esters or amides are preferable.

Specifically, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether; diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, and diethylene glycol dibutyl ether; ethylene glycol alkyl ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate;

Examples thereof include alkylene glycol alkyl ether acetates such as propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, and methoxypentyl acetate; aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; ketones such as methyl ethyl ketone, acetone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, and glycerin; esters such as ethyl 3-ethoxypropionate and methyl 3-methoxypropionate; and cyclic esters such as γ-butyrolactone.

The above solvent may be included in an amount of 60 to 90 wt%, preferably 70 to 85 wt%, based on the total weight of the photosensitive resin composition. When the above solvent is in the range of 60 to 90 wt% as described above, it provides an effect of improving the coatability when applied using a coating device such as a roll coater, a spin coater, a slit-and-spin coater, a slit coater (sometimes also called a die coater), or an inkjet.

In addition to the above components, the photosensitive resin composition of the present invention may also contain additives such as antioxidants, fillers, other polymer compounds, curing agents, adhesion promoters, ultraviolet absorbers, and anti-coagulants, as needed by those skilled in the art, within a range that does not impair the purpose of the present invention.

Commercially available antioxidants include ADK STAB AO-30, ADK STAB AO-40, ADK STAB AO-50F, ADK STAB AO-60, ADK STAB AO-80, ADK STAB 1178, ADK STAB TPP, ADK STAB 1500, ADK STAB 135A, and ADK STAB 3010 from Adeka.

Specifically, the filler may be glass, silica, alumina, etc., but is not limited thereto.

The above other polymer compounds may specifically include, but are not limited to, curable resins such as epoxy resins and maleimide resins, thermoplastic resins such as polyvinyl alcohol, polyacrylic acid, polyethylene glycol monoalkyl ether, polyfluoroalkyl acrylate, polyester, and polyurethane.

The above curing agent is used to increase deep curing and mechanical strength, and specifically, epoxy compounds, polyfunctional isocyanate compounds, melamine compounds, oxetane compounds, etc. can be used, but are not limited thereto. Specifically, the epoxy compound can be bisphenol A-based epoxy resin, hydrogenated bisphenol A-based epoxy resin, bisphenol F-based epoxy resin, hydrogenated bisphenol F-based epoxy resin, novolak-type epoxy resin, other aromatic epoxy resins, alicyclic epoxy resins, glycidyl ester-based resins, glycidyl amine-based resins, or brominated derivatives of these epoxy resins, aliphatic, alicyclic or aromatic epoxy compounds other than epoxy resins and brominated derivatives thereof, butadiene (co)polymer epoxides, isoprene (co)polymer epoxides, glycidyl (meth)acrylate (co)polymers, triglycidyl isocyanurate, etc., but are not limited thereto. The above oxetane compound may specifically be, but is not limited to, carbonate bisoxetane, xylene bisoxetane, adipate bisoxetane, terephthalate bisoxetane, cyclohexane dicarboxylic acid bisoxetane, etc.

The above curing agent can be used together with a curing auxiliary compound which can cause the epoxy group of the epoxy compound and the oxetane skeleton of the oxetane compound to ring-open and polymerize together with the curing agent. Specific examples of the above curing auxiliary compound include polycarboxylic acids, polycarboxylic anhydrides, and acid generators. The above carboxylic anhydrides can be those commercially available as epoxy resin curing agents. Examples of the commercially available epoxy resin curing agents include product names such as (ADEKAHADONA EH-700) (manufactured by ADEKA Kogyo Co., Ltd.), (RIKASHIDO HH) (manufactured by Shin Nippon Eika Co., Ltd.), and (MH-700) (manufactured by Shin Nippon Eika Co., Ltd.).

The curing agents and curing auxiliary compounds exemplified above may be used alone or in combination of two or more.

The adhesion accelerator may be specifically selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane, or a mixture thereof. there is.

The above ultraviolet absorbent may specifically be, but is not limited to, 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzothiazole, alkoxybenzophenone, etc.

The above-mentioned anti-coagulant may specifically include, but is not limited to, sodium polyacrylate.

It is preferable that the above additive be included in an amount of 0.01 to 20 wt%, preferably 0.1 to 10 wt%, based on the total weight of the photosensitive resin composition.

The above exposure process may include ultraviolet exposure (e.g., using a g-line, h-line, i-line, or KrF light source) using a mask that selectively exposes the pixel area. Thereafter, the unexposed area is selectively removed using a developer, thereby forming the pattern having the desired pattern shape.

The developer may include, for example, an inorganic or organic alkaline compound. Examples of the inorganic alkaline compounds include sodium hydroxide, potassium hydroxide, disodium hydrogen phosphate, sodium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, sodium silicate, potassium silicate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium borate, potassium borate, ammonia, and the like. Examples of the organic alkaline compounds include tetramethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, ethanolamine, and the like. These may be used alone or in combination of two or more.

After the above development process, the column spacer (500) pattern can be more firmly hardened through an additional heating hardening process (post-bake, post-firing). At this time, the heating temperature can be 90 to 180°C, and the heating time can be 5 to 180 minutes, preferably 15 to 90 minutes, but is not limited thereto.

A method for manufacturing a variable transmittance optical laminate according to one embodiment of the present invention includes a step (S104) of peeling off a carrier substrate (400) including the temperature-sensitive adhesive layer (300).

After forming the above column spacer (500), it can be peeled off at 0°C or lower, and preferably at -40 to 0°C.

Therefore, as described above, due to the change in the peeling force characteristics of the temperature-sensitive adhesive layer at 0℃ or lower, the temperature-sensitive adhesive layer (300) can be cleanly peeled from the polarizing film, so that the carrier substrate (400) can be easily peeled.

< Optical laminate with variable transmittance >

The present invention includes a transmittance variable optical laminate manufactured according to the method for manufacturing a transmittance variable optical laminate described above.

FIG. 4 is a diagram showing the laminated structure of a transmittance variable optical laminate manufactured by a method for manufacturing a transmittance variable optical laminate according to another embodiment of the present invention.

The optical laminate with variable transmittance of the present invention may include a plurality of polarizing films (100), transparent conductive layers (200), and column spacers (500), and may be a laminate in the form of a liquid crystal layer (550) disposed therebetween. In this case, for example, a first laminate (10) is prepared by the method described above in which a lower polarizing film (100-1), a lower transparent conductive layer (200-1), and a column spacer (500) are sequentially laminated, and an upper polarizing film (100-2) on which an upper transparent conductive layer (200-2) is formed is separately prepared as a second laminate (20), and the transparent conductive layer (200) and the polarizing film (100) are disposed to face each other with the column spacer (500) as the center, and a liquid crystal compound is injected or dropped into the space between them in which the column spacer (500) is formed, thereby disposing the liquid crystal layer (550). The above first laminate (10) and second laminate (20) may further include an adhesive layer (600), an alignment film (250-1, 250-2), an ultraviolet absorption layer, a hard coating layer, etc., as needed.

The liquid crystal layer (550) can change the driving mode of the optical laminate by controlling the transmittance of light incident from one or more directions according to an electric field, and includes a liquid crystal compound. The liquid crystal compound is not particularly limited as long as it is capable of controlling the transmittance of light by being driven according to an electric field, and a liquid crystal compound developed in the past or later can be used. For example, the content regarding the reactive liquid crystal compound of the above-described coated polarizer can be equally applied.

The liquid crystal behavior of the above liquid crystal compound is not particularly limited, and for example, it can be driven in a TN (Twisted nematic) mode, but is not limited thereto, and can also be driven in an STN (Super twisted nematic) mode, a VA (Vertical alignment) mode, etc.

In one embodiment, the liquid crystal layer (550) may be driven in a TN (Twisted Nematic) mode. In this case, the optical design with the polarizing film (100) described above may improve the transmittance variable range between the light-transmitting mode and the light-shielding mode of the optical laminate, and there may be an advantage in that the optical laminate can be easily enlarged.

The optical laminate with variable transmittance of the present invention may further include other members within a range that does not impair the purpose of the present invention, for example, it may further include an adhesive layer (600) on one or both sides of the optical laminate, and may further include an alignment film (250-1, 250-2), an ultraviolet absorption layer, a hard coating layer, etc.

The above adhesive layer (600) can be formed using an adhesive, and it is preferable that it have appropriate adhesive strength to prevent peeling, bubbles, etc. from occurring when handling the optical laminate, while also having transparency and thermal stability.

The adhesive may be a conventional or later-developed adhesive, and in one or more embodiments, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyvinyl alcohol adhesive, a polyvinyl pyrrolidone adhesive, a polyacrylamide adhesive, a cellulose adhesive, a vinyl alkyl ether adhesive, or the like may be used. The adhesive is not particularly limited as long as it has adhesive strength and viscoelasticity, but in terms of ease of acquisition, etc., it may preferably be an acrylic adhesive, and may include, for example, a (meth)acrylate copolymer, a crosslinking agent, a solvent, or the like.

The crosslinking agent may be a crosslinking agent that has been developed in the past or will be developed in the future, and may include, for example, a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, dialdehydes, a methylol polymer, etc., and preferably, a polyisocyanate compound.

The above solvent may include a typical solvent used in the field of resin compositions, and for example, alcohol compounds such as methanol, ethanol, isopropanol, butanol, and propylene glycol methoxy alcohol; ketone compounds such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, and dipropyl ketone; acetate compounds such as methyl acetate, ethyl acetate, butyl acetate, and propylene glycol methoxy acetate; cellosolve compounds such as methyl cellosolve, ethyl cellosolve, and propyl cellosolve; and hydrocarbon compounds such as hexane, heptane, benzene, toluene, and xylene. These may be used alone or in combination of two or more.

The thickness of the adhesive layer (600) may be appropriately determined depending on the type of resin that acts as the adhesive, the adhesive strength, the environment in which the adhesive is used, etc. In one embodiment, the adhesive layer (600) may have a thickness of 0.01 to 50 μm, preferably 0.05 to 20 μm, and more preferably 0.1 to 10 μm, in order to secure sufficient adhesive strength and minimize the thickness of the optical laminate.

The above-mentioned alignment film (250-1, 250-2) may be formed by a rubbing process after applying an alignment film coating composition containing an alignment polymer, a photopolymerization initiator, and a solvent. The alignment polymer is not particularly limited, but may be a polyacrylate-based resin, a polyamic acid resin, a polyimide-based resin, a polymer containing a cinnamate group, etc., and a polymer capable of exhibiting alignment that has been developed in the past or in the future may be used.

The above ultraviolet absorbing layer is not particularly limited as long as it is for preventing deterioration of the optical laminate due to ultraviolet rays, and examples thereof include salicylic acid-based ultraviolet absorbers (phenyl salicylate, p-tert-butyl salicylate, etc.), benzophenone-based ultraviolet absorbers (2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, etc.), benzotriazole-based ultraviolet absorbers (2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidemethyl)-5'-methylphenyl)benzotriazole, 2,2-Methylenebis(4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol), 2-(2'-Hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-tert-butyl-5'-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, 2-(2'-Hydroxy-3'-(1-methyl-1-phenylethyl)-5'-(1,1,3,3-tetramethylbutyl)-phenyl)benzotriazole, 2-(2H-benzotriazol-2-yl)-6-(linear and branched dodecyl)-4-methylphenol, mixtures of octyl-3-[3-tert-butyl-4-hydroxy-5-(chloro-2H-benzotriazol-2-yl)phenyl]propionate and 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, etc.), cyanoacrylate-based ultraviolet absorbers (2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-(3',4'-methylenedioxyphenyl)-acrylate, etc.), triazine-based ultraviolet absorbers, etc., can be used, and benzotriazole-based ultraviolet absorbers with high transparency and excellent effect in preventing deterioration of polarizing films or variable transmittance layers, Triazine-based UV absorbers are preferred, and benzotriazole-based UV absorbers having a more appropriate spectral absorption spectrum are particularly preferred. The benzotriazole-based UV absorbers may be bis-based, and examples thereof include 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol), 6,6'-methylenebis(2-(2H-benzo[d][1,2,3]triazol-2-yl)-4-(2-hydroxyethyl)phenol), and the like.

The above hard coating layer is not particularly limited as long as it is for protecting components such as a polarizing film and a variable transmittance layer from external physical or chemical impacts, and a hard coating layer developed previously or later may be used.

In one embodiment, the hard coating layer can be formed by applying a composition for forming a hard coating layer on another member and then curing it with light or heat. The composition for forming the hard coating layer is not particularly limited and may include, for example, a photocurable compound and a photoinitiator.

The photocurable compound and photoinitiator can be used without limitation as those commonly used in the art, for example, the photocurable compound can be a photopolymerizable monomer, a photopolymerizable oligomer, etc., and examples thereof include monofunctional and/or polyfunctional (meth)acrylates, and the photoinitiator can include oxime esters, etc.

<Smart Window>

The present invention includes a smart window including the same, in addition to the transmittance variable optical laminate manufactured by the method for manufacturing the above-described transmittance variable optical laminate. In addition, the present invention includes a means of transportation including the smart window, for example, an automobile applying the smart window to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition, a wearable device including the smart window, and an architectural window.

및 약1bar 진공 상태에서 10~20분 가열하여 제조된 것일 수 있고, 상기 접착 필름은 EVA 필름, PVB 필름 등을 포함하는 것일 수 있다. For example, an automobile including a smart window of the present invention may be a vehicle glass (700) bonded on both sides of an optical laminate including a polarizing film (100), a transparent conductive layer (200), a liquid crystal layer, and an adhesive layer (600) (see FIG. 5), and for example, an adhesive film and vehicle glass are placed on both sides of the optical laminate, and then a press machine is used to press the vehicle glass at a temperature of 90

And it can be manufactured by heating for 10 to 20 minutes in a vacuum state of about 1 bar, and the adhesive film can include an EVA film, a PVB film, etc.

In addition, a building window (window glass, 800) may be bonded to one side (see FIG. 6a) or both sides (see FIG. 6b) of the optical laminate, and a smart window product for a window having the same configuration as FIG. 6a may be manufactured by bonding window glass to one side of the optical laminate in a laminated manner, and a smart window product for a window having the same configuration as FIG. 6b may be manufactured by bonding window glass to both sides of the optical laminate after applying UV adhesive thereto and then UV curing.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and these embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the invention of the scope of the invention, and the present invention is defined only by the scope of the claims.

Manufacturing example

Manufacturing Example 1: Manufacturing of polarizing film

(1) Swelling treatment process

A 60 ㎛ thick polyvinyl alcohol film (fabric film) (manufactured by Kuraray Co., Ltd., trade name "Kurare Poval Film VF-PE#6000", average degree of polymerization 2400, degree of saponification 99.9 mol%) was continuously unwound from a fabric roll and conveyed, and immersed in a swelling bath containing pure water at 20°C for 30 seconds. In this swelling treatment process, interrolling (longitudinal uniaxial stretching) was performed by providing a difference in peripheral speed between the nip rolls. The stretching ratio based on the fabric film was 2.5 times.

(2) Dyeing process

Next, the film passed through the nip roll was immersed in a dyeing bath at 30°C with a mass ratio of pure/potassium iodide/iodine/boric acid of 100/2/0.01/0.3 for 120 seconds. In this dyeing treatment, inter-rolling (longitudinal uniaxial stretching) was performed by providing a difference in peripheral speed between the nip rolls. The stretching ratio based on the film after the swelling treatment process was set to 1.1 times.

(3) Cross-linking process

Next, the film that passed through the nip roll was immersed in a first crosslinking bath having a mass ratio of 100/12/4 in a 56°C pure potassium iodide/boric acid at a temperature of 100°C for 70 seconds. Roll-to-roll stretching (longitudinal uniaxial stretching) was performed by providing a difference in peripheral speed between the nip roll and the nip roll provided between the first crosslinking bath and the second crosslinking bath. The stretching ratio based on the film after the dyeing treatment process was set to 1.9 times.

(4) Complementary color treatment process

Next, the film after cross-linking treatment was immersed in a second cross-linking bath at 40°C containing potassium iodide/boric acid/pure water (mass ratio) of 9/2.9/100 for 10 seconds.

(5) Cleaning process

Next, the film after the second cross-linking treatment was immersed in a washing bath containing pure water at 14°C for 5 seconds, and washed with a shower amount of 5 m ³ /h and a shower temperature of 14°C.

(6) Drying process

Next, the film after the cleaning process was passed through a drying oven, and was dried by heating at 80°C for 190 seconds to produce a polarizer film. The moisture content after drying was 13.6%, and the thickness of the obtained polarizer film was approximately 21 μm.

(7) Bonding process

Next, as an adhesive, an aqueous adhesive containing 5 parts by mass of polyvinyl alcohol per 100 parts by mass of water was prepared. Thereafter, a protective film was laminated on both sides of the polarizing film using the prepared UV adhesive. The obtained laminate was exposed to UV light and the adhesive was cured to produce an upper polarizing film and a lower polarizing film, respectively. In addition, the thickness of the adhesive layer in the obtained polarizing film was about 2 ㎛.

Manufacturing Example 2: Manufacturing of a composition for forming a hard coating layer

A composition for forming a hard coating layer was prepared by mixing 16.2 g of a dendrimer compound (Miwon Specialty Chemical, 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-hydroxycyclohexyl phenyl ketone), and 2.9 g of methyl ethyl ketone.

Manufacturing Example 3: Production of a hard coating layer

The composition for forming a hard coating layer manufactured in the above Manufacturing Example 2 was bar-coated on one side of each of the upper and lower polarizing films manufactured in Manufacturing Example 1 by adjusting the Mayer Bar type and solid content to calculate the hard coating thickness after curing, and then dried at 80° C. for 5 minutes and cured with a high-pressure mercury lamp at a light amount of 500 mJ/cm2 to manufacture an upper and lower polarizing film, respectively, having a hard coating layer formed on one side.

Manufacturing Example 4: Fabrication of a transparent conductive layer

The upper and lower polarizing films manufactured in the above Manufacturing Example 3 were placed, 450 W DC power was applied to operate the sputter gun, and plasma was induced on the ITO (10 wt% Sn doped In ₂ O ₃ ) target to form an upper transparent conductive layer and a lower transparent conductive layer with a thickness of 90 nm. The formed transparent conductive layer was ion-treated by operating the ion gun with 50 W DC power. At this time, the pressure was maintained at 3 mTorr at room temperature, and argon gas and oxygen gas were supplied at 30 sccm and 1 sccm, respectively, while manufacturing. At this time, the ITO thickness was measured by FT-SEM, and the ITO sheet resistance (Ω/□) was measured using a four point probe.

Manufacturing Example 5: Production of a thermosensitive adhesive layer

<Manufacture of thermosensitive adhesive>

The temperature-sensitive adhesive is supplied in a form in which a release film is bonded to both sides of a temperature-sensitive adhesive layer. At room temperature, peeling occurs due to the difference in peel strength between the release films on both sides and the temperature-sensitive adhesive layer, and peeling from the temperature-sensitive adhesive layer occurs with respect to the release film with a weaker peel strength among the two sides of the adhesive layer. The temperature-sensitive adhesive is manufactured by including a side crystalline polymer, a cross-linking agent, and an antistatic agent, and the desired temperature-sensitive adhesive can be manufactured by appropriately adjusting the contents of the above components. The adhesive strength of the side of the temperature-sensitive adhesive that comes into contact with a polarizing film, when measured according to JIS Z0237 (180° pulling peeling), was 1.5 N/25 mm at 25°C and 0.03 N/25 mm at -20°C based on a polyimide film.

Cut the temperature-sensitive adhesive to the desired shape and size and prepare it for bonding to the carrier substrate.

<Carrier substrate bonding>

On the carrier substrate, a release film having a weak peeling force among the release films from the above temperature-sensitive adhesive is peeled off and attached to the carrier substrate using a roller under conditions of room temperature to 60°C or lower. Thereafter, the remaining release films are peeled off and attached to the back surface of the lower polarizing film, where the transparent conductive layer and the alignment film are not formed, under conditions of room temperature to 60°C.

Manufacturing Example 6: Manufacturing of Column Spacer

<Manufacture of binder resin>

A flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping lot, and a nitrogen introduction tube was prepared.

As a monomer loading lot, 40 parts by weight of a mixture of 3,4-epoxytricyclodecan-8-yl (meth)acrylate and 3,4-epoxytricyclodecan-9-yl (meth)acrylate in a molar ratio of 50:50, 50 parts by weight of methyl methacrylate, 40 parts by weight of acrylic acid, 70 parts by weight of vinyltoluene, 4 parts by weight of t-butylperoxy-2-ethylhexanoate, and 40 parts by weight of propylene glycol monomethyl ether acetate (PGMEA) were added, and stirring was prepared.

As a chain transfer agent loading tank, 6 parts by weight of n-dodecanethiol and 24 parts by weight of PGMEA were added and stirring was prepared. Thereafter, 395 parts by weight of PGMEA was added to the flask, and the atmosphere inside the flask was exchanged from air to nitrogen, and the temperature of the flask was raised to 90°C while stirring. Thereafter, the monomer and the chain transfer agent were started to be dropped from the dropping lot. The dropping was performed for 2 hours each while maintaining 90°C, and after 1 hour, the temperature was raised to 110°C and maintained for 5 hours to obtain a binder resin having a solid acid value of 100 mg KOH/g and a weight average molecular weight of 17000 and not including Si-O bonds.

<Preparation of photosensitive resin composition>

A photosensitive resin composition was prepared by mixing 12.41 wt% of the obtained binder resin, 0.59 wt% of MA0701 (POSS, Hybrid Plastic Inc.) and 5.32 wt% of dipentaerythritol hexaacrylate (Kayarad DPHA: Nippon Kayaku Co., Ltd.) as photopolymerizable compounds, 1.58 wt% of ethanone-1-[9-ethyl-6-(2-methyl-4-tetrahydropyranyloxybenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) (Irgacure OXE-02: Ciba) as a photopolymerization initiator, 0.1 wt% of BYK-052N (BYK) as an additive, and 80 wt% of propylene glycol monomethyl ether acetate (PGMEA) as a solvent.

<Spacer formation>

Using the above photosensitive resin composition, a cured film pattern was formed by the following method. A spin coater was used to coat the transparent conductive layer of the lower polarizing film obtained in Manufacturing Example 5 at 300 rpm to form a resin coating layer. After coating, the film was dried at a temperature of 80° C. for 2 minutes using a hot plate to have a coating film thickness of 6 μm. Thereafter, the film was exposed to active energy rays such as ultraviolet rays at an irradiation energy dose of 60 mJ/cm2. The film obtained by exposure was developed (developing time 60 seconds) using a developer (0.04% KOH aqueous solution, 25° C.) to form a pattern. After development, the film was placed in an 80° C. convection oven and post-baked for 60 minutes.

Manufacturing Example 7: Manufacturing of an Alignment Film

TN alignment solution (RN-4662, Nissan Chemical Industries, Ltd.) was coated and dried (80°C, 2 minutes) on the column spacer manufactured in the above Manufacturing Example 6. Thereafter, UV was irradiated on the dried alignment solution to manufacture an alignment film.

<Carrier substrate peeling>

For the polarizing film on which the above alignment film, column spacer, and transparent conductive layer are laminated, the carrier substrate is peeled off at -40 to 0°C. When peeling, the polarizing film is peeled off while holding the corner ends thereof, and the temperature-sensitive adhesive layer and the polarizing film are peeled off due to changes in the peeling force characteristics of the temperature-sensitive adhesive layer at -40 to 0°C. The temperature-sensitive adhesive layer and the carrier substrate are peeled off together in an attached state.

Manufacturing Example 8: Manufacturing of optical laminate

A sealant (UVF-006, 70,000 mPa s, SEKISUI) was applied to the outer surface of the lower polarizing film manufactured in the above Manufacturing Example 7 using a sealant dispenser (SHOTmini 200Ωx, USASHI) according to the product size. Then, liquid crystal was injected onto the alignment layer of the upper polarizing film using the ODF process while the polarization axes of the upper polarizing film and the lower polarizing film were arranged parallel to each other at 0° or 90°. Thereafter, the upper polarizing film and the lower polarizing film were bonded at a pressure of 1.5 kg/cm ² , and UV curing (500 mJ/cm ² ) was performed along the sealant line to manufacture an optical laminate for a smart window.

Examples and Comparative Examples

Example 1

An optical laminate of Example 1 was manufactured according to Manufacturing Examples 1 to 8 above.

Comparative Example 1

An optical laminate of Comparative Example 1 was manufactured in the same manner as in Example 1, except that the temperature-sensitive adhesive layer manufacturing of Manufacturing Example 5 and the subsequent <carrier substrate peeling> step of Manufacturing Example 7 were excluded.

division Carrier substrate bonding/peeling Whether the polarizing film is deformed Example 1 Bonding ○, Peeling ○ No deformation Comparative Example 1 Bonding X, Peeling X There is a variation

Referring to Table 1 above, when a transmittance variable optical laminate is manufactured by using the temperature-sensitive adhesive of the present invention, even when a process of applying heat treatment to a flexible polarizing film is performed, the polarizing film is not deformed, and further, it can be seen that the carrier substrate, which assists in the process progress for the flexible film, is easily peeled off after the process is completed, and thus, no deformation of the polarizing film occurs.

In contrast, in the case of Comparative Example 1, which did not use the temperature-sensitive adhesive and carrier substrate of the present invention, it was observed that deformation occurred in the polarizing film as the process of forming the spacer proceeded.

100: Polarizing film 100-1: Lower polarizing film
100-2: Top polarizing film 200: Transparent conductive layer
200-1: Lower transparent conductive layer 200-2: Upper transparent conductive layer
250-1: Alignment film 250-2: Alignment film
300: Thermosensitive adhesive layer 400: Carrier substrate
500: Column spacer 550: Liquid crystal layer
600: Adhesive layer 700: Automotive glass
800: Windows for buildings 10: Iridescent film
20: Thermosensitive adhesive 30: Release film

Claims (12)

A step of forming a transparent conductive layer on one side of a polarizing film;
A step of bonding a carrier substrate including a temperature-sensitive adhesive layer to the back surface of the polarizing film;
A step of forming a column spacer on the above challenge layer; and
A method for manufacturing a transmittance variable optical laminate, comprising: a step of peeling off a carrier substrate including the temperature-sensitive adhesive layer;
In claim 1,
A method for manufacturing a transmittance variable optical laminate, wherein the temperature-sensitive adhesive layer has an adhesive strength on a surface in contact with the polarizing film of 1.0 N/25 mm to 2.0 N/25 mm at 25 to 50°C and 0.05 N/25 mm or less at -40 to 0°C, when measured in accordance with JIS Z0237 (180° peeling) based on a polyimide film.
In claim 1,
A method for manufacturing a variable transmittance optical laminate, wherein the temperature-sensitive adhesive layer is formed from a temperature-sensitive adhesive including a release film on both sides, and the temperature-sensitive adhesive has different adhesive strengths from the release films on both sides.
In claim 1,
A method for manufacturing a transmittance variable optical laminate, wherein the step of forming the column spacer includes the step of applying a photosensitive resin composition on the conductive layer and performing a heat treatment.
In claim 1,
A method for manufacturing a variable transmittance optical laminate, wherein the step of peeling off the carrier substrate comprises peeling off the variable transmittance optical laminate on which the column spacer is formed at 0°C or lower.
In claim 1,
A method for manufacturing a variable transmittance optical laminate, wherein the transparent conductive layer is formed in direct contact with the polarizing film without including a separate substrate between the transparent conductive layer and the polarizing film.
In claim 1,
A method for manufacturing a variable transmittance optical laminate, wherein the transparent conductive layer is formed by direct contact with the polarizing film, including an adhesive-friendly layer.
In claim 1,
A method for manufacturing a transmittance variable optical laminate, wherein the transparent conductive layer comprises at least one selected from the group consisting of transparent conductive oxides, metals, carbon-based materials, conductive polymers, conductive inks, and nanowires.
A transmittance variable optical laminate manufactured by the manufacturing method of any one of claims 1 to 8.
A variable transmittance optical laminate according to claim 9, wherein the variable transmittance optical laminate further comprises at least one selected from the group consisting of an adhesive layer, an alignment film, an ultraviolet absorbing layer, and a hard coating layer.
polarizing film;
A transparent conductive layer formed on one side of the polarizing film;
A column spacer formed on the transparent conductive layer; and
A carrier substrate is included that is adhered to the back surface of the polarizing film through a temperature-sensitive adhesive layer,
A variable transmittance optical laminate, wherein the carrier substrate is removed after forming the column spacer.
A smart window comprising a variable transmittance optical laminate of claim 9.

Images