Optical laminate and smart window including the same

Abstract

The present invention includes a dimming laminate including a first polarizing plate, a first transparent conductive layer formed on one surface of the first polarizing plate, a second polarizing plate facing the first polarizing plate, a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer, and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, at least one of a surface protection film and a hard coating layer being provided on one surface or both surfaces of the dimming laminate. At least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizing plate and the second polarizing plate. The surface protection film has a peel strength of 1.0 N / 25 mm to 2.4 N / 25 mm, and the hard coating layer has a surface pencil hardness of HB to 6H. The present invention relates to a variable transmittance optical laminate and a smart window including the same.

Description

Technical Field

[0001] The present invention relates to an optical laminate and a smart window including the same.

Background Art

[0002] Generally, an external light blocking coating is often applied to the glass window of a moving means such as a vehicle. However, the glass window of a conventional moving means has a fixed transmittance, and the external light blocking coating also has a fixed transmittance. Therefore, the overall transmittance of such a conventional moving means window is fixed, which may induce an accident. For example, when the overall transmittance is set low, there is no problem during the daytime when the amount of light in the surroundings is sufficient, but in the case of nighttime when the amount of light in the surroundings is not sufficient, there is a problem that it is only difficult for a driver or the like to properly check the surroundings of the moving means. Or when the overall transmittance is set high, there is a problem that it may cause glare to a driver or the like during the daytime when the amount of light in the surroundings is sufficient. Thus, a variable transmittance optical laminate that can change the light transmittance when a voltage is applied has been developed.

[0003] On the other hand, when trying to fabricate a smart window using such a variable transmittance optical laminate, generally, after fabricating the optical laminate, glass is bonded to one or both surfaces of the optical laminate for fabrication.

[0004] However, before the optical laminate is bonded to glass, that is, during the handling process such as the fabrication or transportation of the optical laminate, if surface damage or scratches occur on the optical laminate, there are problems such as a decrease in the optical properties of the optical laminate.

[0005] Therefore, it is necessary to protect the optical laminate from surface damage or scratches that may occur during the handling process of the optical laminate itself used for fabricating the smart window.

[0006] Therefore, a surface protection film that adheres to one or both surfaces of the optical laminate and can protect the optical laminate from surface damage or scratches is used. For example, Korean Patent Publication No. 10-2001-0101097 also discloses a surface protection film.

[0007] However, in the case of such a surface protection film, when the peeling force with respect to the adhesion surface is not sufficient, there is a problem that bubbles are generated at the interface between the surface protection film and the adhesion surface during the vapor deposition process such as ITO. When the peeling force with respect to the adhesion surface is excessively large, there are problems such as the internal film of the laminate being peeled off during the peeling process or bubbles flowing into the liquid crystal.

[0008] Korean Patent Publication No. 10-2001-0101097 also had a problem that the peeling force was not sufficient for use in the manufacturing process of the optical laminate for a smart window, and bubbles were generated at the interface between the surface protection film and the adhesion surface during the ITO vapor deposition process.

[0009] Therefore, there is an emerging need for an optical laminate provided with a surface protection film or the like that can protect the optical laminate without such problems occurring.

Summary of the Invention

Problems to be Solved by the Invention

[0010] An object of the present invention is to provide a variable transmittance optical laminate that can protect the dimming laminate from external impacts or scratches and prevent damage to the dimming laminate that may occur during the process.

Means for Solving the Problems

[0011] To achieve the above object, the present invention includes a first polarizing plate, a first transparent conductive layer formed on one surface of the first polarizing plate, a second polarizing plate facing the first polarizing plate, a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer, and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer. The light control laminate includes at least one of a surface protection film and a hard coating layer on one or both surfaces of the light control laminate. At least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizing plate and the second polarizing plate. The surface protection film has a peel strength of 1.0 N / 25 mm to 2.4 N / 25 mm, and the hard coating layer has a surface pencil hardness of HB to 6H, providing a variable transmittance optical laminate.

Advantages of the Invention

[0012] According to the optical laminate according to an embodiment of the present invention, the peel strength of the surface protection film is optimized, and damage to the sealant and inflow of air bubbles into the liquid crystal can be prevented when the surface protection film is peeled off.

[0013] Also, according to the optical laminate according to an embodiment of the present invention, the peel strength of the surface protection film is optimized, and inflow of air bubbles between the light control laminate and the surface protection film can be prevented during vacuum deposition of the transparent conductive layer.

[0014] Also, according to the optical laminate according to another embodiment of the present invention, the surface pencil hardness of the hard coating layer is optimized, and even without a surface protection film on the optical laminate, the surface of one or both surfaces of the light control laminate can be protected from post-processes and the external environment.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2a

Figure 2b

Figure 2c

Figure 2d

Figure 2e

Figure 3

Figure 4

Figure 5a

Figure 5b

Figure 5c

Figure 6a

Figure 6b

Figure 6c

Mode for Carrying Out the Invention

[0016] The present invention relates to a transmissivity variable optical laminate that can prevent damage to the sealant and inflow of air bubbles into the liquid crystal when peeling the surface protection film by optimizing the peel force of the surface protection film, and can prevent the inflow of air bubbles between the dimming laminate and the surface protection film during vacuum deposition of the transparent conductive layer.

[0017] The present invention also relates to a transmissivity variable optical laminate that can protect one or both surfaces of the dimming laminate from post-processes and the external environment by optimizing the surface pencil hardness of the hard coating layer, even without a surface protection film on the optical laminate.

[0018] More specifically, it includes a dimming laminate including a first polarizing plate, a first transparent conductive layer formed on one surface of the first polarizing plate, a second polarizing plate facing the first polarizing plate, a second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer, and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer. At least one of a surface protection film and a hard coating layer is provided on one or both surfaces of the dimming laminate. At least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizing plate and the second polarizing plate. The surface protection film has a peel force of 1.0 N / 25 mm to 2.4 N / 25 mm, and the hard coating layer has a surface pencil hardness of HB to 6H. The present invention relates to a transmissivity variable optical laminate.

[0019] The transmissivity variable optical laminate of the present invention is particularly suitable for the technical field where the light transmissivity can be changed by applying a voltage, and may be used, for example, in a smart window.

[0020] A smart window refers to an optical structure that controls the amount of light or heat transmitted by changing the light transmittance upon application of an electrical signal. That is, a smart window is provided so that it can change to a transparent, opaque, or translucent state by voltage, and is also called variable transmittance glass, dimming glass, or smart glass.

[0021] Smart windows can be used for partitioning the interior spaces of vehicles and buildings or as privacy protection partitions, or may be used as daylighting windows arranged at the openings of buildings. They may also be used for highway signs, bulletin boards, scoreboards, clocks, or advertising screens, and can be used to replace the glass of means of transportation such as the windows or sunroofs of automobiles, buses, airplanes, ships, or trains.

[0022] The variable transmittance optical laminate of the present invention can also be used for smart windows in the various technical fields described above. However, since the conductive layer is formed directly on the polarizing plate, it does not include a separate substrate for forming the conductive layer, so it has a thin thickness and is advantageous in terms of bending characteristics, and may be particularly preferably used for smart windows for vehicles or buildings. In one or more embodiments, a smart window to which the variable transmittance optical laminate of the present invention is applied can be used for means of transportation, for example, the front window, rear window, side window, and sunroof window of an automobile, or building fixtures. In addition to applications for blocking external light, it can also be used for partitioning the interior space of an automobile or building or for privacy protection, such as internal partitions, and may also be used for wearable devices such as helmets, glasses, or watches.

[0023] Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to better understand the technical idea of the present invention together with the content of the aforementioned invention. Therefore, the present invention should not be construed as being limited only to the matters described in these drawings.

[0024] The terms used in this specification are for the purpose of describing embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated otherwise in the text. For example, the "polarizing plate" used in this specification may mean at least one of the first polarizing plate and the second polarizing plate, and the "transparent conductive layer" may mean at least one of the first transparent conductive layer and the second transparent conductive layer.

[0025] As used in this specification, "comprises" and / or "comprising" are used in a sense that does not exclude the presence or addition of one or more other components, steps, operations, and / or elements other than the recited components, steps, operations, and / or elements. The same reference numerals throughout the specification refer to the same components.

[0026] Spatially relative terms such as "lower", "bottom surface", "lower part", "upper", "upper surface", "upper part", etc. can be used to easily describe the correlation between one element or component and another element or component as shown in the drawings. Spatially relative terms should be understood as terms that include different directions of elements relative to each other during use or operation in addition to the directions shown in the drawings. For example, when covering an element shown in the drawing, an element described as "lower" or "lower part" of another element may be placed "above" the other element. Therefore, the exemplary term "lower" can include both the lower and upper directions. The element can also be oriented in other directions, and thus the spatially relative terms can be interpreted according to the orientation.

[0027] As used herein, the "plane direction" can be interpreted as the direction perpendicular to the polarizing plate and / or the transparent conductive layer, that is, the direction viewed from the user's viewing side.

[0028] FIG. 1 is a diagram showing the laminated structure of a light control laminate according to an embodiment of the present invention, FIG. 2 is a diagram showing the laminated structure of a polarizing plate according to one or more embodiments of the present invention, FIGS. 3 and 4 are diagrams showing the laminated structure of a variable transmittance optical laminate according to one or more embodiments of the present invention, and FIGS. 5 and 6 are diagrams showing the laminated structure of a smart window according to one or more embodiments of the present invention.

[0029] Referring to FIG. 1, the light control laminate 100 according to an embodiment of the present invention may include a first polarizing plate 200-1, a second polarizing plate 200-2, a first transparent conductive layer 300-1, a second transparent conductive layer 300-2, and a liquid crystal layer 400.

[0030] Referring to FIG. 2, the polarizing plate 200 may include a polarizer 210, and may further include functional layers such as a protective layer 220, a retardation adjusting layer 230, and a refractive index adjusting layer 240 on one or both surfaces of the polarizer 210. For example, the polarizing plate 200 may include a polarizer 210 and a protective layer 220 laminated on one or both surfaces of the polarizer 210 (see FIGS. 2a and 2b), or may include a polarizer 210, a protective layer 220 laminated on one surface of the polarizer 210, and a retardation adjusting layer 230 laminated on the other surface opposite to the one surface of the polarizer 210 (see FIG. 2c), or may include a polarizer 210, a protective layer 220 laminated on one surface of the polarizer, a retardation adjusting layer 230 and a refractive index adjusting layer 240 laminated in sequence on the other surface opposite to the one surface of the polarizer 210 (see FIG. 2d), or may include a polarizer 210, a protective layer 220 laminated on one surface of the polarizer, and a protective layer 220 and a retardation adjusting layer 230 laminated in sequence on the other surface opposite to the one surface of the polarizer 210 (see FIG. 2e).

[0031] The polarizer 210 may use a conventional or future-developed polarizer. For example, a stretched polarizer or a coating polarizer may be used.

[0032] In one embodiment, the stretched 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. Examples of the polyvinyl acetate-based resin include polyvinyl acetate which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of the other monomers may include unsaturated carboxylic acid-based, unsaturated sulfonic acid-based, olefin-based, vinyl ether-based, acrylamide-based monomers having an ammonium group, etc. The polyvinyl alcohol (PVA)-based resin also includes modified ones, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

[0033] In one embodiment, the coating polarizer may be formed by a liquid crystal coating composition. At this time, the liquid crystal coating composition may include a reactive liquid crystal compound, a dichroic dye, etc.

[0034] The reactive liquid crystal compound can mean, for example, a compound containing a mesogen skeleton and further containing one or more polymerizable functional groups. Such reactive liquid crystal compounds are variously known under the name of so-called RM (Reactive Mesogen). The reactive liquid crystal compound can form a cured film in which a polymer network is formed while maintaining a liquid crystal alignment by being polymerized by light or heat.

[0035] The reactive liquid crystal compound may be a monofunctional or polyfunctional reactive liquid crystal compound. The monofunctional reactive liquid crystal compound is a compound having one polymerizable functional group, and the polyfunctional reactive liquid crystal compound can mean a compound containing two or more polymerizable functional groups.

[0036] The dichroic dye is a component contained in the liquid crystal coating composition and imparts polarization characteristics, and has the property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic dye may use a conventional or later-developed dichroic dye. For example, it may contain one or more selected from the group consisting of azo dyes, anthraquinone dyes, perylene dyes, merocyanine dyes, azomethine dyes, phthaloperylene dyes, indigo dyes, dioxazine dyes, polythiophene dyes, and phenoxazine dyes.

[0037] The liquid crystal coating composition may further contain a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye. For example, propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene, chloroform, etc. may be used. Further, the liquid crystal coating composition may further contain a leveling agent, a polymerization initiator, etc. within a range that does not impair the polarization characteristics of the coating film.

[0038] The protective layer 220 is for preserving the polarization characteristics of the polarizer 210 from subsequent processes and the external environment, and can be embodied in the form of a protective film or the like.

[0039] The protective layer 220 may be formed in direct contact with one or both surfaces of the polarizer 210 as shown in FIGS. 2a and 2b, but is not limited thereto. For example, the protective layer may be used as a multilayer structure in which one or more protective layers are continuously laminated, or may be formed in direct contact with other members.

[0040] In one or more embodiments, the protective layer 220 may include one or more 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).

[0041] The retardation adjusting layer 230 may be formed in direct contact with one surface of the polarizer 210 as shown in FIGS. 2c and 2d, but is not limited thereto. For example, as shown in FIG. 2e, the retardation adjusting layer 230 may be formed on one surface of the protective layer 220, and the polarizer 210, the protective layer 220, and the retardation adjusting layer 230 may be sequentially laminated.

[0042] The retardation adjustment layer 230 may be a polymer stretched film or a liquid crystal polymer film obtained by stretching a polymer film capable of imparting optical anisotropy by stretching in an appropriate manner.

[0043] In one embodiment, the polymer stretched film may be a polyolefin such as polyethylene (PE) or polypropylene (PP), a cyclic olefin polymer (COP) such as polynorbornene, polyvinyl chloride (PVC), polyacrylonitrile (PAN), polysulfone (PSU), an acrylic resin, a polycarbonate (PC), a polyester such as polyethylene terephthalate (PET), a polyacrylate, a cellulose ester-based polymer such as polyvinyl alcohol (PVA) or triacetyl cellulose (TAC), or a copolymer of two or more monomers in the monomers forming the polymer, etc., and a polymer layer may be used.

[0044] The method for obtaining the polymer stretched film is not particularly limited. For example, it can be obtained by stretching the polymer material after forming it into a film shape. The method for forming it into a film shape is not particularly limited, and it can be formed into a film by known methods such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, extrusion molding, foam molding, and cast molding. Secondary processing molding methods such as pressure air molding and vacuum molding may also be used. Among them, extrusion molding and cast molding are preferably used. At this time, for example, an unstretched film can be extrusion molded using an extruder equipped with a T-die, a circular die, etc. When obtaining a molded product by extrusion molding, a material obtained by previously melt-kneading various resin components, additives, etc. can be used, or it can also be molded through melt-kneading during extrusion molding. Further, after dissolving various resin components using a solvent common to various resin components, such as a solvent such as chloroform or methylene dichloride, an unstretched film may be cast molded by cast drying and solidification.

[0045] The polymer stretched film may be uniaxially stretched in the machine flow direction (MD; Mechanical Direction, longitudinal direction or length direction) of the formed film, or uniaxially stretched in the direction transverse to the machine flow direction (TD; Transverse Direction, transverse direction or width direction). Also, a biaxially stretched film may be manufactured 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.

[0046] The liquid crystal polymer film can contain the reactive liquid crystal compound in a polymerized state. The content regarding the reactive liquid crystal compound of the coating type polarizer described above can be similarly applied to the reactive liquid crystal compound.

[0047] In one or more embodiments, the thickness of the retardation adjustment layer 230 may be from 10 μm to 100 μm in the case of a polymer stretched film, and may be from 0.1 μm to 5 μm in the case of a liquid crystal polymer film.

[0048] The refractive index adjustment layer 240 is provided to compensate for the refractive index difference of the optical laminate due to the transparent conductive layer 300, and may serve to improve visual recognition characteristics and the like by reducing the refractive index difference. Further, the refractive index adjustment layer 240 may be provided to correct the hue caused by the transparent conductive layer 300. On the other hand, when the transparent conductive layer has a pattern, the transmittance difference between the pattern region where the pattern is formed and the non-pattern region where the pattern is not formed can be compensated through the refractive index adjustment layer.

[0049] Specifically, the transparent conductive layer 300 is laminated adjacent to another member (for example, a polarizer) having a different refractive index from it, and a difference in light transmittance may be induced due to the refractive index difference from the adjacent other layer. In particular, when a pattern is formed on the transparent conductive layer, a problem may occur in that it can be visually recognized so as to distinguish the pattern region and the non-pattern region. Therefore, by including the refractive index adjustment layer, the refractive index is compensated so that the difference in light transmittance of the optical laminate can be reduced. In particular, when a pattern is formed on the transparent conductive layer, the pattern region and the non-pattern region are not distinguished and not visually recognized.

[0050] In one embodiment, the refractive index of the refractive index adjustment layer 240 may be appropriately selected depending on the material of another adjacent member, but is preferably from 1.4 to 2.6, and more preferably may be from 1.4 to 2.4. In this case, light loss due to a sharp refractive index difference between the transparent conductive layer 300 and another member such as the polarizer 210 can be prevented.

[0051] The refractive index adjustment layer 240 is not particularly limited as long as it can prevent a sharp refractive index difference between the transparent conductive layer 300 and another member such as the polarizer 210, and a compound used for forming a conventional or later-developed refractive index adjustment layer may be used. For example, it may be formed from a refractive index adjustment layer forming composition containing a polymerizable isocyanurate compound.

[0052] In one embodiment, the polarizing plate 200 may further include other configurations for assisting or enhancing the characteristics of the polarizer in addition to the above-described components. For example, in order to further improve mechanical durability, it may further include an overcoat layer or the like.

[0053] In one or more embodiments, the polarizing plate 200 may have a thickness of 30 to 200 μm, preferably 30 to 170 μm, and more preferably 50 to 150 μm. In this case, the polarizing plate 200 enables the production of an optical laminate with a thin thickness while maintaining optical characteristics.

[0054] The transparent conductive layer 300 is provided for driving the liquid crystal layer 400 and may be formed in direct contact with the polarizing plate 200. For example, as shown in FIG. 1, the first transparent conductive layer 300-1 and the second transparent conductive layer 300-2 may be formed in direct contact with the first polarizing plate 200-1 and the second polarizing plate 200-2, respectively.

[0055] An optical laminate used in the production of conventional smart windows or the like is manufactured by forming a conductive layer for liquid crystal driving on one surface of a substrate and bonding the other surface of the substrate to a polarizing plate. However, the light control laminate 100 according to the present invention is characterized in that, without including a separate substrate for forming the conductive layer, the conductive layer is directly formed on one surface of the polarizing plate, thereby reducing the thickness of the laminate and improving the transmittance and bending characteristics in the light transmission mode.

[0056] In one embodiment, the transparent conductive layer 300 may be formed by directly depositing on one surface of the polarizing plate 200. At this time, in order to improve the adhesion between the transparent conductive layer 300 and the polarizing plate 200, after performing a pretreatment such as corona treatment or plasma treatment on one surface of the polarizing plate 200, it may be formed in direct contact with the pretreated surface of the polarizing plate 200. The pretreatment is not limited to corona treatment or plasma treatment, and pretreatment steps that are conventional or developed in the future may be used as long as the object of the present invention is not impaired.

[0057] In another embodiment, in order to improve the adhesion between the transparent conductive layer 300 and the polarizing plate 200, it may be formed in direct contact with the polarizing plate 200 with an easy-adhesion layer (not shown) provided on one surface of the polarizing plate 200 interposed therebetween.

[0058] The transparent conductive layer 300 preferably has a transmittance of 50% or more with respect to visible light. For example, it may include one or more selected from the group consisting of transparent conductive oxides, metals, carbon-based substances, conductive polymers, conductive inks, and nanowires, but is not limited thereto, and materials of conventional or future-developed transparent conductive layers may be used.

[0059] 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), and zinc oxide (ZnO). Further, 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, for example, it may include a silver - palladium - copper (APC) alloy or a copper - calcium (CuCa) alloy. The carbon - based material may include one or more selected from the group consisting of carbon nanotubes (CNT) and graphene. The conductive polymer may include one or more 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).

[0060] Further, the transparent conductive layer 300 may be formed in a structure of two or more layers by combining the substances. For example, it may be formed in a two - layer structure including a metal layer and a transparent conductive oxide layer so as to reduce the reflectivity of incident light and increase the transmittance.

[0061] The liquid crystal layer 400 can change the driving mode of the optical laminate by adjusting the transmittance of light incident from one or more directions by an electric field.

[0062] The liquid crystal layer 400 may include a liquid crystal compound and a spacer. For example, as shown in FIG. 1, it may mean a region defined by a first alignment film 500-1, a second alignment film 500-2, and a sealant 600.

[0063] The liquid crystal compound is driven by an electric field and is not particularly limited as long as it can control the light transmittance. Conventional or newly developed liquid crystal compounds may be used. For example, the content related to the reactive liquid crystal compound of the coating type polarizer described above may be equally applicable.

[0064] The liquid crystal behavior mode of the liquid crystal layer 400 is not particularly limited. For example, as shown in FIG. 1, it may be driven in a TN (Twisted nematic) mode, but is not limited thereto, and may also be driven by an STN (Super twisted nematic) mode, a VA (Vertical alignment) mode, an ECB (Electrically controlled birefringence) mode, etc.

[0065] The spacer may include at least one or more spacers among ball spacers and column spacers, and is particularly preferably a ball spacer. The spacer may be one or more, and preferably has a height of 1 μm to 10 μm. Also, at this time in the planar direction, the area occupied by the spacer in the liquid crystal layer 400 is preferably 0.01 to 10% of the area of the liquid crystal layer 400 from the viewpoints of user visibility and improvement of transmittance in the light transmission mode.

[0066] In one embodiment, the liquid crystal layer 400 may further include an alignment film 500 as needed, for example, it may be formed on both surfaces of the liquid crystal layer 400 containing a liquid crystal compound.

[0067] The alignment film 500 is not particularly limited as long as it can impart alignment properties to the dispersed liquid crystal, and preferably, it may contain a photo-alignable or photocurable polymer or the like. For example, the alignment film 500 can be fabricated by applying and curing an alignment film coating composition containing a photo-alignable or photocurable polymer, a photoinitiator, and a solvent.

[0068] The photo-alignable or photocurable polymer is not particularly limited, and a cinnamate-based polymer, a polyimide-based polymer, or the like may be used. For example, poly(vinyl cinnamate) (PVCi), poly(siloxane cinnamate) (PSCN), poly(ω(4-chalconyloxy)alkoxyphenylmaleimide, 6-FDA-HAB-Cl, or the like may be used, and a polymer that can exhibit alignment properties, whether conventional or developed in the future, may also be used.

[0069] The sealant 600 is located between the first polarizing plate 200-1 and the second polarizing plate 200-2 in the non-active region, serves to bond the first polarizing plate and the second polarizing plate, and may be provided to secure a space between the first polarizing plate 200-1 and the second polarizing plate 200-2 where the liquid crystal layer 400 is provided together with spacers.

[0070] The sealant 600 may contain a curable resin as a base resin. As the base resin, an ultraviolet curable resin or a thermosetting resin known to be used in sealants in the art may be used. The ultraviolet curable resin may be a polymer of an ultraviolet curable monomer. The thermosetting resin may be a polymer of a thermosetting monomer.

[0071] As the base resin of the sealant 600, for example, an acrylate resin, an epoxy resin, a urethane resin, a phenol resin, or a mixture of the resins may be used. In one embodiment, the base resin may be an acrylate resin, and the acrylate resin may be a polymer of an acrylic monomer. The acrylic monomer may be, for example, a polyfunctional acrylate. In other embodiments, the sealant may further contain a monomer component in the base resin. The monomer component may be, for example, a monofunctional acrylate. In the present specification, the monofunctional acrylate can mean a compound having one acrylic group, and the polyfunctional acrylate can mean a compound having two or more acrylic groups. The curable resin can be cured by irradiation with ultraviolet rays and / or heating. The ultraviolet irradiation conditions or heating conditions may be appropriately carried out within a range that does not impair the object of the present application. The sealant may further contain an initiator, for example, a photoinitiator or a thermal initiator, if necessary.

[0072] The sealant 600 may be formed by a method commonly used in the art. For example, it may be formed by drawing the sealant onto the outer contour (i.e., the inactive region) of the liquid crystal layer using a dispenser equipped with a nozzle.

[0073] Referring to FIG. 3, the transmissivity variable optical laminate according to an embodiment of the present invention may include a dimming laminate 100 and surface protection films 700 formed on both surfaces of the dimming laminate.

[0074] The surface protection film 700 may be provided for the purpose of preventing scratches, contamination, corrosion, etc. on the surface that may occur during the manufacture, transportation, or storage of the dimming laminate 100, and may be peeled off and removed from the dimming laminate before glass such as vehicle glass 910 or building glass 920 adheres to the dimming laminate 100 (see FIG. 5).

[0075] The surface protection film 700 preferably has a peeling force with respect to the light - modulating laminate of 1.0 N / 25 mm to 2.4 N / 25 mm. The peeling force may be measured at a speed of 300 mm / min for the 180° peeling force (N / 25 mm) between the light - modulating laminate 100 and the surface protection film using a Universal Testing Machine. When the peeling force of the surface protection film satisfies the above range, there is no air - bubble inflow into the optical laminate or damage to the sealant during the production of the light - modulating laminate 100 or when peeling the surface protection film 700, and the durability of the optical laminate may be further improved.

[0076] The surface protection film 700 may include a base film and an adhesive layer formed on the base film.

[0077] The base film may use a conventional or later - developed base film. For example, it may include one or more selected from the group consisting of polyolefin - based films, polyester - based films, acrylic - based films, styrene - based films, amide - based films, polyvinyl chloride - based films, polyvinylidene chloride - based films, and polycarbonate - based films. Considering the deformability during the production, transportation, or storage process of the light - modulating laminate 100 and the bondability with the light - modulating laminate 100, the thickness of the base film may be 10 μm to 300 μm.

[0078] The adhesive layer may be formed using an adhesive. It preferably has an appropriate adhesive force so that only the surface protection film 700 can be cleanly removed from the light - modulating laminate 100 when peeling the surface protection film 700 without affecting other members such as the sealant, and has transparency and thermal stability.

[0079] The adhesive may be a conventional adhesive or an adhesive developed in the future. 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, etc. may be used. The adhesive is not particularly limited as long as it has adhesiveness and viscoelasticity, but from the viewpoint of easy availability, etc., it may preferably be an acrylic adhesive, for example, it may contain a (meth)acrylate copolymer, a crosslinking agent, a solvent, etc.

[0080] The crosslinking agent may be a conventional crosslinking agent or a crosslinking agent developed in the future. For example, it may contain a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, dialdehydes, a methylol polymer, etc., and preferably may contain a polyisocyanate compound.

[0081] The solvent may include ordinary solvents used in the field of resin compositions. For example, alcohol-based compounds such as methanol, ethanol, isopropanol, butanol, propylene glycol monomethyl ether; ketone-based compounds such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone; acetate-based compounds such as methyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate; cellosolve-based compounds such as methyl cellosolve, ethyl cellosolve, propyl cellosolve; hydrocarbon-based compounds such as hexane, heptane, benzene, toluene, xylene, etc. may be used as the solvent. These may be used alone or in combination of two or more.

[0082] The thickness of the adhesive layer 400 may be appropriately determined according to the type of resin serving as the adhesive, the adhesive strength, the environment in which the adhesive is used, and the like. In one embodiment, in order for the peeling force of the surface protection film 700 to be from 1.0 N / 25 mm to 2.4 N / 25 mm, the adhesive layer may have a thickness of from 1 μm to 30 μm.

[0083] Referring to FIG. 4, a variable transmittance optical laminate according to another embodiment of the present invention may include a dimming laminate 100 and a hard coating layer 800 formed on both surfaces of the dimming laminate.

[0084] The hard coating layer 800 may be provided to protect members such as a polarizing plate, a variable transmittance layer, and a dimming laminate from external physical and chemical impacts, and in terms of serving to protect the dimming laminate 100 from the external environment, it can perform substantially the same function as the surface protection layer 700 described above. Therefore, when the variable transmittance optical laminate of the present invention includes the hard coating layer 800, the surface protection film 700 may not be included (see FIGS. 4 and 6).

[0085] In order for the hard coating layer 800 to serve to protect the dimming laminate 100 from the external environment, the surface pencil hardness is preferably from HB to 6H. The surface pencil hardness may be measured by applying a 500 g load using a pencil hardness tester (manufactured by SUKBO Science Co., Ltd., Korea) to measure the pencil hardness of the hard coating layer, or the pencil may be a Mitsubishi product and performed 5 times for each pencil hardness, and heat-treated at 100° C. for 10 minutes to evaluate whether scratches are visually confirmed. When the surface pencil hardness of the hard coating layer satisfies the above range, the hard coating layer has excellent abrasion resistance, so that surface defects can be prevented in subsequent processes.

[0086] The hard coating layer 800 may use a conventional or later-developed hard coating layer. For example, it may be formed from a hard coating composition containing an acrylate-based or epoxy-based compound, inorganic fine particles, and / or a photoinitiator. The acrylate-based compound may include a monomer or oligomer containing a (meth)acrylate group. The term "(meth)acryl-" used herein is used to mean "methacryl-", "acryl-", or both. Non-limiting examples of the acrylate-based compound include neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexatri(meth)acrylate, bis(2-hydroxyethyl) isocyanurate di(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, or isobornyl (meth)acrylate. These may be used alone or in combination of two or more.The acrylate compound may include an epoxy (meth)acrylate compound and / or a urethane (meth)acrylate compound. Further, the epoxy compound may include a monomer or oligomer having at least one epoxy group in the molecule. The epoxy group may be an alicyclic epoxy group. The number of carbon atoms of the alicyclic ring contained in the epoxy group may be 3 to 7. For example, it may be an alicyclic epoxy group (cyclohexyl epoxy) containing a cyclohexane ring. The alicyclic ring may have a substituent. For example, the alicyclic ring may include an alkyl substituent having 1 to 20 carbon atoms. When the number of carbon atoms of the alkyl substituent exceeds 20, it may be disadvantageous in terms of the curing rate. The alkyl substituent includes a linear or branched type, and in the case of a branched type, the number of carbon atoms may be 3 or more.

[0087] According to one embodiment of the present invention, in a method for manufacturing a hard coating film, the hard coating composition includes inorganic fine particles. According to one embodiment of the present invention, as the inorganic fine particles, inorganic fine particles having a particle size in the nanoscale, for example, nano fine particles having a particle size of 100 nm or less, or 10 to 100 nm, or 10 to 50 nm may be used. Further, as the inorganic fine particles, for example, silica fine particles, aluminum oxide particles, titanium oxide particles, zinc oxide particles, or the like may be used.

[0088] By including the inorganic fine particles, the hardness of the hard coating layer can be further improved. According to one embodiment of the present invention, the inorganic fine particles may be included in an amount of 10 to 60 parts by weight, or 20 to 50 parts by weight, based on 100 parts by weight of the hard coating composition. By including the inorganic fine particles within the above range, the effect of improving the hardness of the hard coating layer due to the addition of the inorganic fine particles can be achieved within a range where the physical properties of the hard coating composition are not deteriorated.

[0089] According to an embodiment of the present invention, in a method for manufacturing a hard coating film, the hard coating composition contains a photoinitiator. According to an embodiment of the present invention, examples of the photoinitiator include, but are not limited to, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, methyl benzoylformate, α,α-dimethoxy-α-phenylacetophenone, 2-benzoyl-2-(dimethylamino-)-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide, or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Also, commercially available products currently include Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 907, Darocur 1173, Darocur MBF, Irgacure 819, Darocur TPO, Irgacure 907, Esacure KIP 100F, and the like. These photoinitiators may be used alone or in combination of two or more different ones.

[0090] According to an embodiment of the present invention, the photoinitiator may be contained in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the hard coating composition. When the photoinitiator is within the above range, sufficient crosslinking photopolymerization can be achieved without degrading the physical properties of the hard coating layer.

[0091] On the one hand, in the method for manufacturing the hard coating film of the present invention, in addition to the above-mentioned components, the hard coating composition may further contain additives commonly used in the technical field to which the present invention pertains, such as surfactants, anti-yellowing agents, leveling agents, or antifouling agents. Further, since the content thereof can be adjusted in various ways within a range that does not deteriorate the physical properties of the hard coating composition according to the present invention, it is not particularly limited.

[0092] In one or more embodiments, the thickness of the hard coating layer 800 may be from 1 μm to 50 μm, preferably may be more than 2 μm and less than 23 μm, and more preferably may be from 3 μm to 20 μm. The thickness may mean the thickness after drying. When the thickness of the hard coating layer 800 satisfies the above range, there are advantages in terms of excellent flexural resistance and durability, and the ability to achieve thinning.

[0093] On the one hand, FIG. 3 illustrates an example where the surface protection film 700 is formed on both surfaces of the light control laminate 100, and FIG. 4 illustrates an example where the hard coating layer 800 is formed on both surfaces of the light control laminate, but it is not necessarily limited thereto. For example, a variable transmittance optical laminate according to another embodiment of the present invention may include a light control laminate; a surface protection film formed on one surface of the light control laminate; and a hard coating layer formed on the other surface of the light control laminate opposite to the one surface.

[0094] The present invention includes, in addition to the variable transmittance optical laminate, a smart window including the same. Further, the present invention includes an automobile 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 building fixtures for a building including the smart window.

[0095] For example, the automobile including the smart window of the present invention may be one in which vehicle glass 910 is bonded to both surfaces of a variable transmittance optical laminate from which a surface protection film 700 has been peeled off (see FIG. 5a), or may be one in which vehicle glass 910 is bonded to both surfaces of a variable transmittance optical laminate including a hard coating layer 800 (see FIG. 6a). For example, the smart window including the vehicle glass may be manufactured by placing an adhesive film and vehicle glass on both surfaces of the optical laminate and then heating at a temperature of 90° C. and a vacuum state of about 1 bar for 10 to 20 minutes using a press machine. The adhesive film may include an EVA film, a PVB film, or the like.

[0096] Alternatively, it may be one in which a building fitting (glass for building fittings) 920 is bonded to both surfaces or one surface of the variable transmittance optical laminate. After applying a UV adhesive to the glass for building fittings on both surfaces of the optical laminate and bonding them, and then UV curing, a building fitting smart window product having the same configuration as FIGS. 5b and 6b may be manufactured. It may also be one in which a building fitting smart window product having the same configuration as FIGS. 5c and 6c is manufactured by bonding the glass for building fittings to one surface of the optical laminate in a laminating manner.

Example

[0097] Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the embodiments disclosed below and can be embodied in various different forms. Merely, these embodiments are provided to complete the disclosure of the present invention and to fully inform those with ordinary knowledge in the technical field to which the present invention pertains of the scope of the invention. The present invention is only defined by the scope of the claims.

[0098] Production Example 1: Production of a Polarizing Plate (1) Swelling treatment step A polyvinyl alcohol film with a thickness of 60 μm (original film) (manufactured by Kuraray Co., Ltd., trade name "Kuraray Poval Film VF-PE#6000", average degree of polymerization 2400, saponification degree 99.9 mol%) was continuously unwound from the original roll and conveyed, and immersed in a swelling bath containing pure water at 20°C for 30 seconds. In this swelling treatment step, a difference in peripheral speed was created between the nip rolls to perform stretching between the rolls (uniaxial stretching in the longitudinal direction). The stretching ratio based on the original film was set to 2.5 times.

[0099] (2) Dyeing treatment step Next, the film that passed through the nip rolls was immersed in a dyeing bath at 30°C with a mass ratio of pure water / potassium iodide / iodine / boric acid of 100 / 2 / 0.01 / 0.3 for 120 seconds. Also in this dyeing treatment, a difference in peripheral speed was created between the nip rolls to perform stretching between the rolls (uniaxial stretching in the longitudinal direction). The stretching ratio based on the film after the swelling treatment step was set to 1.1 times.

[0100] (3) Crosslinking treatment step Next, the film that passed through the nip rolls was immersed in a first crosslinking bath at 56°C with a mass ratio of pure water / potassium iodide / boric acid of 100 / 12 / 4 for 70 seconds. A difference in peripheral speed was created between the nip rolls and the nip roll provided between the first crosslinking bath and the second crosslinking bath to perform stretching between the rolls (uniaxial stretching in the longitudinal direction). The stretching ratio based on the film after the dyeing treatment step was set to 1.9 times.

[0101] (4) Complementary color treatment step Next, the film after the crosslinking treatment was immersed in a second crosslinking bath at 40°C with a mass ratio of potassium iodide / boric acid / pure water of 9 / 2.9 / 100 for 10 seconds.

[0102] (5) Washing treatment step Next, the film after the second crosslinking treatment was immersed in a washing bath containing pure water at 14°C for 5 seconds, and washed at a shower rate of 5 m 3 / h and a shower temperature of 14°C.

[0103] (6) Drying treatment step Next, the film after the washing process was passed through a drying furnace and heated and dried 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.

[0104] (7) Bonding process Next, an aqueous adhesive containing 5 parts by mass of polyvinyl alcohol with respect to 100 parts by mass of water was prepared as an adhesive. Then, a first triacetyl cellulose (TAC) protective film (60 μm) and a second triacetyl cellulose (TAC) protective film (40 μm) were laminated on both sides of the polarizer film using the prepared UV adhesive. The obtained laminate was subjected to UV exposure to cure the adhesive and produce a polarizing film. Also, the thickness of the adhesive layer in the obtained polarizing film was approximately 2 μm.

[0105] Production Example 2: Production of a hard coating composition 16.2 g of a dendrimer compound (manufactured by Miwa Specialty Chemicals Co., Ltd., SP-1106), 14.4 g of inorganic nanoparticles (10 to 20 nm, silica particles: 50% by weight, solvent: methyl ethyl ketone (MEK)), 1.8 g of a polyfunctional (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 were mixed to produce a hard coating composition.

[0106] Production Example 3: Production of a hard coating layer (HC2) After drying the hard coating composition produced in Production Example 2 on one side of the second triacetyl cellulose (TAC) protective film (thickness 40 μm) of a polarizing plate, the thickness was adjusted with a Mayer bar type and bar-coated, dried at 80°C for 5 minutes, and then irradiated with a high-pressure mercury lamp at 500 mJ / cm 2A polarizing plate was fabricated by curing with a light amount such that a hard coating layer (HC2) was formed on one side. Using a thickness measuring instrument (MH-15M, manufactured by SENDAI NIKON), the thickness of the polarizing plate after the formation of the hard coating layer (HC2) and the thickness of the polarizing plate before the formation of the hard coating layer (HC2) were measured, and as a result of calculating the difference between the two thicknesses, the thickness of the hard coating layer (HC2) was 8 μm.

[0107] Production Example 4: Production of Surface Protection Film (PF) Using a surface protection film (manufactured by LGC, LDM-EPCB) on the opposite side of the hard coating layer (HC2) of the polarizing plate produced in Production Example 3, a 20-μm adhesive layer and a 38-μm PET film were attached by a lamination method to produce a polarizing plate with a surface protection film attached.

[0108] Production Example 5: Production of Transparent Conductive Layer (ITO / IML) The polarizing plate with the surface protection film of Production Example 4 was placed, and after applying 450 W of DC power to operate the sputtering gun, plasma was induced on the ITO (10 wt% Sn doped In2O3) target to form a transparent conductive layer (90 nm) on one surface of the hard coating layer (HC2), and a first conductive laminate and a second conductive laminate having a laminated structure of surface protection film / polarizing plate / hard coating layer / transparent conductive layer were each fabricated. Ion treatment was performed on the formed transparent conductive layer by operating the ion unit with 50 W of DC power. At this time, the pressure was maintained at 3 mTorr at room temperature, and production was carried out while supplying argon gas and oxygen gas at 30 sccm and 1 sccm, respectively. At this time, the ITO performance was measured for the ITO thickness by FT-SEM, and the ITO sheet resistance (Ω / □) was measured using a four-point probe.

[0109] Production Example 6: Production of Alignment Film An alignment liquid was coated and dried (80 °C / 2 minutes) on the transparent conductive layers (ITO / IML) of each of the first and second conductive laminates produced in Production Example 5. Thereafter, by irradiating UV on the dried alignment liquid to form an alignment film, an upper laminate and a lower laminate having a laminated structure of a surface protection film / polarizing plate / hard coating layer / transparent conductive layer / alignment film were produced respectively.

[0110] Production Example 7: Production of Ball Spacer Spraying The mixed solvent was produced by mixing 0.03 g of ball spacers (SEKISUI, SP series) based on 100 ml of IPA. Thereafter, the lower laminate of Production Example 6 was placed in a spacer spraying machine (SDSS-KHU02, SHINDO ENG LAB), and the produced mixed solvent was sprayed under the condition of 110 °C and then dried for 20 minutes to form ball spacers on the alignment film of the lower laminate of Production Example 6.

[0111] Production Example 8: Production of Transmittance Variable Optical Laminate Using a sealant dispenser (SHOTmini 200Ωx, MUSASHI) on the surface of the transparent conductive layer (ITO / IML) of the lower laminate on which ball spacers were formed according to Production Example 7, a sealant (UVF-006, 70,000 mPa·s, SEKISUI) was applied according to the product size drawing at a discharge pressure of 200 mPa using a sharp needle (SPN-0.25-12.7L). Liquid crystal was injected onto the alignment film by the ODF (One Drop Filling) process method. Thereafter, with the polarizing axes of the polarizing plates provided in the upper laminate of Production Example 6 and the lower laminate arranged parallel to each other at 0° or 90°, they were joined under a pressure of 3 Kg / cm 2 pressure to produce a transmittance variable optical laminate for a smart window.

[0112] Examples and Comparative Examples Example 1 The transmittance variable optical laminate of Example 1 was produced according to Production Examples 1 to 8 above.

[0113] Example 2 Except for being manufactured using the surface protection film (manufactured by Fujimori Kogyo Co., Ltd., AY-638) in Production Example 4, a transmittance variable optical laminate of Example 2 was manufactured in the same manner as in Example 1.

[0114] Example 3 Except for manufacturing a hard coating layer (HC1) instead of the surface protection film in Production Example 4, a transmittance variable optical laminate of Example 3 was manufactured in the same manner as in Example 1. The hard coating layer (HC1) was manufactured to a thickness of 3 μm using a Mayer bar, and the manufacturing method was the same as in Production Example 3.

[0115] Example 4 Except for manufacturing a hard coating layer (HC1) instead of the surface protection film in Production Example 4, a transmittance variable optical laminate of Example 4 was manufactured in the same manner as in Example 1. The hard coating layer (HC1) was manufactured to a thickness of 20 μm using a Mayer bar, and the manufacturing method was the same as in Production Example 3.

[0116] Comparative Example 1 Except for being manufactured using the surface protection film (manufactured by LGC Co., Ltd., LDM-EPHC) in Production Example 4, a transmittance variable optical laminate of Comparative Example 1 was manufactured in the same manner as in Example 1.

[0117] Comparative Example 2 Except for being manufactured using the surface protection film (manufactured by Fujimori Kogyo Co., Ltd., AS3-501) in Production Example 4, a transmittance variable optical laminate of Comparative Example 2 was manufactured in the same manner as in Example 1.

[0118] Comparative Example 3 Except for manufacturing a hard coating layer (HC1) instead of the surface protection film in Production Example 4, a transmittance variable optical laminate of Comparative Example 3 was manufactured in the same manner as in Example 1. The hard coating layer (HC1) was manufactured to a thickness of 2 μm using a Mayer bar, and the manufacturing method was the same as in Production Example 3.

[0119] Comparative Example 4 A variable transmittance optical laminate of Comparative Example 4 was produced in the same manner as in Example 1, except that a hard coating layer (HC1) was produced instead of the surface protection film in Production Example 4. The hard coating layer (HC1) was produced to a thickness of 23 μm using a Mayer bar, and the production method was the same as in Production Example 3.

[0120] Experimental Example (1) Evaluation of peel strength The variable transmittance optical laminates of Example 1 and 2 and Comparative Example 1 and 2 were cut into pieces of size 25 mm * 250 mm using a super cutter, and then bonded to an adhesive glass plate to produce test pieces. After fixing the produced test pieces to a universal testing machine, the 180° peel strength (N / 25 mm) between the dimming laminate and the surface protection film was measured at a speed of 300 mm / min. The measurement results are shown in Tables 1 and 2 below.

[0121] (2) Apparent reliability evaluation For the optical laminates of Example 1 and 2 and Comparative Example 1 and 2, after peeling the surface protection films from both sides of a 38” size (800x500 mm) optical laminate by the method described in Korean Patent Publication No. 10-2013-0060879, the presence or absence of sealant breakage and bubble generation was confirmed. The evaluation results are shown in Tables 1 and 2 below. <Evaluation criteria> ○: Good evaluation result (no sealant breakage and no bubble generation within the liquid crystal area) Χ: Poor evaluation result (bubble generation within the adhesive layer during ITO evaporation or sealant breakage or bubble generation during peeling)

[0122] (3) Measurement of the thickness of the hard coating layer (HC1) For the optical laminates of Example 3 and 4 and Comparative Examples 3 and 4, using a thickness measuring instrument (MH-15M, manufactured by SENDAI NIKON), the thickness of the polarizing plate after forming the hard coating layer (HC1) and the thickness of the polarizing plate before forming the hard coating layer (HC1) were measured, and the difference between the two thicknesses was calculated to obtain the thickness of the hard coating layer (HC1). The measurement results are shown in Tables 1 and 2 below.

[0123] (4) Evaluation of surface pencil hardness For the optical laminates of Example 3 and 4 and Comparative Examples 3 and 4, using a pencil hardness tester (Pencil Hardness Tester, manufactured by SUKBO Science Co., Korea), a load of 500 g was applied to measure the surface pencil hardness of the hard coating surface. Mitsubishi products were used for the pencils, and the test was carried out 5 times for each pencil hardness. After heat treatment at 100 °C for 10 minutes, scratches were visually confirmed. The evaluation results are shown in Tables 1 and 2 below.

[0124] (5) Steel wool test For the optical laminates of Example 3 and 4 and Comparative Examples 3 and 4, using a steel wool tester (WT-LCM100, manufactured by Protech Co., Korea), under a load of 1 kg / (2 cm x 2 cm), the speed was 100 mm / sec, and 10 reciprocating motions were performed to conduct an experiment on the abrasion resistance of the hard coating surface of the optical laminate. Steel wool #0000 was used. The evaluation results are shown in Tables 1 and 2 below. <Evaluation criteria> ○: 0 scratches, no discoloration △: 1 to 10 scratches, no discoloration Χ: More than 10 scratches, discoloration confirmed (visually)

[0125] (6) Reliability mandrel evaluation For the optical laminates of Example 3 and 4 and Comparative Examples 3 and 4, a sample with an upper / lower plate joined, sized 100x100 mm, was placed through a cylindrical bending tester (Lab-QD605, manufactured by CKSI) such that the lower plate surface of the polarizing plate hit a steel bar with a diameter of 32 mm, and a 1 Kg load was applied to the outside of the bent part in the bent state. After being placed in a 90°C oven for 2 hours, the sample was left at room temperature, and the bent area was observed to confirm the occurrence of cracks. The evaluation results are shown in Tables 1 and 2 below. <Evaluation Criteria> ○: 0 cracks Χ: 1 or more cracks

[0126]

Table 1

[0127]

Table 2

[0128] Referring to Tables 1 and 2 above, in the case of Examples 1 and 2 where the peel strength of the surface protection film is 1.0 N / 25 mm to 2.4 N / 25 mm respectively, as a result of the apparent reliability evaluation, it can be seen that after peeling the surface protection film, there is no breakage of the sealant and no generation of bubbles within the liquid crystal area. On the other hand, in the case of Comparative Examples 1 and 2 where the peel strength of the surface protection film is 0.7 N / 25 mm and 2.6 N / 25 mm respectively, deviating from 1.0 N / 25 mm to 2.4 N / 25 mm, it can be seen that bubbles are generated at the adhesion interface of the surface protection film during ITO deposition, or the sealant breaks or bubbles are generated during peeling.

[0129] On the one hand, in the case of Examples 3 and 4 where the surface pencil hardness of the hard coating layer is HB to 6H respectively, the results of the steel wool test show that the hard coating layer has excellent abrasion resistance, and it can be seen from the reliability mandrel evaluation that it has excellent bending characteristics and no crack generation. On the other hand, in the case of Comparative Examples 3 and 4 where the surface pencil hardness of the hard coating layer is B and 7H respectively, which deviate from HB to 6H, it can be seen that the results of the steel wool test and the reliability mandrel evaluation for the examples are poor.

[0130] Therefore, when the peel strength of the surface protection film contained in the optical laminate is from 1.0 N / 25 mm to 2.4 N / 25 mm, it is possible to prevent damage to the sealant and the inflow of air bubbles into the liquid crystal when the surface protection film is peeled off. Even when the optical laminate does not have the surface protection film, when it contains a hard coating layer with a surface pencil hardness of HB to 6H, it can be seen that an optical laminate excellent in abrasion resistance and bending characteristics and capable of protecting the polarizing plate from the external environment can be provided.

Industrial Applicability

[0131] According to the optical laminate according to an embodiment of the present invention, the peel strength of the surface protection film is optimized, and damage to the sealant and the inflow of air bubbles into the liquid crystal can be prevented when the surface protection film is peeled off.

Explanation of Signs

[0132] 100: Dimming laminate 200: Polarizing plate 210: Polarizer 220: Protective layer 230: Phase difference adjusting layer 240: Refractive index adjusting layer 300: Transparent conductive layer 400: Liquid crystal layer 500: Alignment film 600: Sealant 700: Surface protection film 800: Hard coating layer 910: Automotive glass 920: Architectural glass

Claims

1. A first polarizing plate, A first transparent conductive layer formed on one surface of the first polarizing plate, A second polarizing plate facing the first polarizing plate, A second transparent conductive layer formed on one surface of the second polarizing plate and facing the first transparent conductive layer, and A light-adjustable laminated body including a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, At least one of a surface protection film and a hard coating layer is provided on one or both surfaces of the light-adjustable laminated body, At least one of the first transparent conductive layer and the second transparent conductive layer is formed in direct contact with one of the first polarizing plate and the second polarizing plate, The surface protection film has a peel strength of 1.0 N / 25 mm to 2.4 N / 25 mm, The hard coating layer has a surface pencil hardness of HB to 6H, a variable transmittance optical laminate.

2. The surface protection film includes a base film and an adhesive layer formed on the base film, and is laminated on the light-adjustable laminated body through the adhesive layer. The variable transmittance optical laminate according to claim 1.

3. The base film includes one or more selected from the group consisting of a polyolefin film, a polyester film, an acrylic film, a styrene film, an amide film, a polyvinyl chloride film, a polyvinylidene chloride film, and a polycarbonate film. The variable transmittance optical laminate according to claim 2.

4. The base film has a thickness of 10 μm to 300 μm. The variable transmittance optical laminate according to claim 2.

5. The adhesive layer has a thickness of 1 μm to 30 μm. The variable transmittance optical laminate according to claim 2.

6. When the surface protection film is peeled from the light-adjustable laminated body, the liquid crystal layer does not break or generate bubbles. The variable transmittance optical laminate according to claim 1.

7. Surface protection films are provided on both surfaces of the light-adjustable laminated body. The variable transmittance optical laminate according to claim 1.

8. Hard coating layers are provided on both surfaces of the light-adjustable laminated body. The variable transmittance optical laminate according to claim 1.

9. A hard coating layer is provided on one surface of the light-adjustable laminated body, and a surface protection film is provided on the other surface facing the one surface of the light-adjustable laminated body. The variable transmittance optical laminate according to claim 1.

10. The variable transmittance optical laminate according to claim 1, wherein the hard coating layer contains one or more selected from the group consisting of acrylate compounds and epoxy compounds.

11. The variable transmittance optical laminate according to claim 1, wherein the hard coating layer has a thickness of 1 μm to 50 μm.

12. The variable transmittance optical laminate according to claim 1, wherein at least one of the first transparent conductive layer and the second transparent conductive layer contains one or more selected from the group consisting of transparent conductive oxides, metals, carbon-based substances, conductive polymers, conductive inks, and nanowires.

13. The variable transmittance optical laminate according to claim 1, wherein at least one of the first polarizing plate and the second polarizing plate contains one or more functional layers selected from the group consisting of a protective layer, a retardation adjusting layer, and a refractive index adjusting layer.

14. The variable transmittance optical laminate according to claim 1, wherein at least one of the first polarizing plate and the second polarizing plate has a thickness of 30 μm to 200 μm.

15. The variable transmittance optical laminate according to claim 1, wherein the liquid crystal layer contains one or more spacers selected from the group consisting of a ball spacer and a column spacer.

16. The variable transmittance optical laminate according to claim 15, wherein the spacer has a height of 1 μm to 10 μm.

17. The variable transmittance optical laminate according to claim 15, wherein the occupied area of the spacer in the liquid crystal layer is 0.01% to 10% of the liquid crystal layer area.

18. The variable transmittance optical laminate according to claim 1, further comprising alignment films on both surfaces of the liquid crystal layer.

19. A smart window comprising the variable transmittance optical laminate according to any one of claims 1 to 18.

20. A means of transportation comprising the smart window according to claim 19.

21. An automobile in which the smart window according to claim 19 is applied to at least one of a front window, a rear window, a side window, a sunroof window, and an interior partition.

22. A wearable device comprising the smart window according to claim 19.

23. An architectural fixture comprising the smart window according to claim 19.

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