KR102229464B1 - Adhesive composition, adhesive film and smart window comprising the same - Google Patents

Abstract

The present invention relates to an adhesive composition, an adhesive film, and a smart window including the same.

Description

Adhesive composition, adhesive film, and smart window containing the same {ADHESIVE COMPOSITION, ADHESIVE FILM AND SMART WINDOW COMPRISING THE SAME}

The present specification relates to an adhesive composition, an adhesive film, and a smart window including the same.

Smart window refers to an active control technology that can reduce energy loss and provide a pleasant environment to consumers by adjusting the transmittance of light coming from the outside. It is a technology that can be applied to parts that require an optical modulation effect of an area.

In general, the smart window includes a polymer dispersed liquid crystal (Polymer Dispersive Liquid Crystal). However, the polymer dispersed liquid crystal had a problem of severe denaturation when irradiated with ultraviolet rays.

In addition, a general adhesive film used to manufacture a smart window has a problem of poor workability and denatured under extreme conditions of high temperature and high humidity.

Accordingly, it can be used to manufacture a smart window, and by securing UV protection, it is possible to prevent the problem that the polymer dispersed liquid crystal is denatured by UV rays, and it is possible to secure workability, and an adhesive film that is not denatured under extreme conditions. There is a need for research on

Patent Publication No. 10-2012-0077916

The present invention is to provide an adhesive composition, an adhesive film, and a smart window thereof.

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

An exemplary embodiment of the present invention is an acrylic resin comprising a linear alkyl group-containing (meth)acrylate monomer polymerization unit, a branched chain alkyl group-containing (meth)acrylate monomer polymerization unit, and a polar functional group-containing monomer polymerization unit; Heat curing agent; And a sunscreen agent, wherein the content of the branched-chain alkyl group-containing (meth)acrylate monomer polymerized unit is 30 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the acrylic resin.

An exemplary embodiment of the present invention provides an adhesive film comprising a cured product of the adhesive composition.

An exemplary embodiment of the present invention is an electrochromic film comprising a polymer dispersed liquid crystal layer, and a conductive layer provided on both surfaces of the polymer dispersed liquid crystal layer; And a window substrate, wherein the window substrate and the electrochromic film are attached through the adhesive film to provide a smart window.

The adhesive composition according to an exemplary embodiment of the present invention may provide an adhesive film capable of minimizing damage due to ultraviolet rays of a conductive film including a polymer dispersed liquid crystal used in a smart window because it has excellent UV blocking properties.

The adhesive composition according to an exemplary embodiment of the present invention can provide an adhesive film that can be easily applied to a large area material such as automobile or architectural glass due to excellent workability.

The adhesive composition according to an exemplary embodiment of the present invention can provide an adhesive film in which adhesive properties are not deteriorated even under extreme conditions of high temperature and high humidity.

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

In the present specification, the term "monomer polymerization unit" may refer to a form in which the monomer is derived from the monomer, and the monomer forms a backbone, for example, a main chain or a side chain of the polymer through a polymerization reaction.

In the present specification, the unit "part by weight" may mean a ratio of weight between each component.

In the present specification, the term "(meth)acrylate" may mean acrylate or methacrylate.

In the present specification, the term "straight-chain alkyl group" may include a carbon chain structure in which an unsaturated bond is not present in the functional group and a separate functional group is not bonded to the side chain, and a chain alkyl having 1 to 20 carbon atoms in the main chain Can mean

In the present specification, the term "branched-chain alkyl group" includes a carbon chain structure in which a separate functional group is bonded to the side chain of the straight-chain alkyl group, and may mean a chain alkyl having 1 to 20 carbon atoms in the main chain.

In the present specification, the term "solid content of the acrylic resin" may mean a solid nonvolatile material included in the acrylic resin, and may mean a residue after drying a solution containing the prepared acrylic resin.

In the present specification, the "weight average molecular weight" may be a value in terms of polystyrene measured by GPC (Gel Permeation Chromatography).

In the present specification, the glass transition temperature (Tg) is measured by heating at a heating rate of 5°C/min in a temperature range of -70°C to 100°C using DSC (Differential Scanning Calorimeter, DSC-STAR3, METTLER TOLEDO) It may be a value determined as the midpoint of the DSC curve.

Hereinafter, the present specification will be described in more detail.

An exemplary embodiment of the present invention is an acrylic resin comprising a linear alkyl group-containing (meth)acrylate monomer polymerization unit, a branched chain alkyl group-containing (meth)acrylate monomer polymerization unit, and a polar functional group-containing monomer polymerization unit; Heat curing agent; And a sunscreen agent, wherein the content of the branched-chain alkyl group-containing (meth)acrylate monomer polymerized unit is 30 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the acrylic resin.

According to an exemplary embodiment of the present invention, the adhesive composition may include the acrylic resin.

Specifically, the acrylic resin may include a linear alkyl group-containing (meth)acrylate monomer polymerization unit, a branched chain alkyl group-containing (meth)acrylate monomer polymerization unit, and a polar functional group-containing monomer polymerization unit.

According to an exemplary embodiment of the present invention, the acrylic resin is prepared by solution polymerization of a solution containing a straight-chain alkyl group-containing (meth)acrylate monomer, a branched-chain alkyl group-containing (meth)acrylate monomer, and a polar functional group-containing monomer. I can. In addition, the method of the solution polymerization is not particularly limited, and the acrylic resin may be prepared through a known polymerization method such as thermal polymerization of the solution, photopolymerization, or dual polymerization of thermal polymerization and photopolymerization.

According to an exemplary embodiment of the present invention, the solution for preparing the acrylic resin may further include a polymerization initiator.

The kind of polymerization initiator is not particularly limited, and may be selected from thermal polymerization initiators or photopolymerization initiators generally used in the art.

According to an exemplary embodiment of the present invention, the linear alkyl group-containing (meth)acrylate monomer may be in a form in which the above-described linear alkyl group is bonded to the (meth)acrylate.

In addition, the content of the polymerized unit of the linear alkyl group-containing (meth)acrylate monomer may be the same as the content of the linear alkyl group-containing (meth)acrylate monomer.

According to an exemplary embodiment of the present invention, the straight-chain alkyl group-containing (meth)acrylate monomer is methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate , n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, and may include at least one of n-octyl (meth)acrylate. However, the present invention is not limited thereto, and may be appropriately selected from (meth)acrylate monomers to which a linear alkyl group is bonded generally known in the art.

According to an exemplary embodiment of the present invention, the linear alkyl group-containing (meth)acrylate monomer may be bonded to the basic skeleton of the acrylic resin, thereby improving mechanical durability and adhesive properties of the acrylic resin.

According to an exemplary embodiment of the present invention, the branched-chain alkyl group-containing (meth)acrylate monomer may have a form in which the aforementioned branched-chain alkyl group is bonded to the (meth)acrylate.

In addition, the content of the branched-chain alkyl group-containing (meth)acrylate monomer polymerization unit may be the same as the content of the branched-chain alkyl group-containing (meth)acrylate monomer.

According to an exemplary embodiment of the present invention, the branched-chain alkyl group-containing (meth)acrylate monomer is t-butyl (meth)acrylate, sec-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2 -It may contain at least one of ethylbutyl (meth)acrylate, isopentyl (meth)acrylate, isohexyl (meth)acrylate, and isononyl (meth)acrylate. However, it is not limited thereto, and may be appropriately selected from (meth)acrylate monomers to which a branched-chain alkyl group is bonded generally known in the art.

According to an exemplary embodiment of the present invention, the branched-chain alkyl group-containing (meth)acrylate monomer may secure mechanical durability of the acrylic resin by forming a basic skeleton of the acrylic resin.

According to an exemplary embodiment of the present invention, the polar functional group-containing monomer may be in a form in which a polar functional group is bonded.

In addition, the content of the polar functional group-containing monomer polymerization unit may be the same as the content of the polar functional group-containing monomer.

According to an exemplary embodiment of the present invention, the polar functional group-containing monomer may include at least one of a hydroxy group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer.

According to an exemplary embodiment of the present invention, the hydroxy group-containing monomer is 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxy It may include at least one of hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, and 2-hydroxypropylene glycol (meth)acrylate, , But is not limited thereto.

According to an exemplary embodiment of the present invention, the carboxy group-containing monomer is acrylic acid, methacrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, and 4-(meth)acrylo. It may include at least one of monooxy butyric acid and acrylic acid duplex, but is not limited thereto.

According to an exemplary embodiment of the present invention, the nitrogen-containing monomer is 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 4-isocyanatobutyl (meth) It may include at least one of acrylate, (meth)acrylamide, N-vinyl pyrrolidone, and N-vinyl caprolactam, but is not limited thereto.

According to an exemplary embodiment of the present invention, the polar functional group-containing monomer may be bonded to the basic skeleton of the acrylic resin, and the adhesive properties of the acrylic resin may be improved.

According to an exemplary embodiment of the present invention, the content of the branched-chain alkyl group-containing (meth)acrylate monomer polymerized unit is 30 parts by weight or more and 50 parts by weight or less, 30 parts by weight or more and 45 parts by weight or less based on 100 parts by weight of the acrylic resin. , 35 parts by weight or more and 50 parts by weight or less, or 35 parts by weight or more and 45 parts by weight or less.

Within the above range, the adhesive film including the cured product of the adhesive composition containing the acrylic resin can secure high mechanical properties, high adhesive properties, and excellent workability even under extreme conditions of high temperature and high humidity.

According to an exemplary embodiment of the present invention, the content of the polymerized unit of the linear alkyl group-containing (meth)acrylate monomer is 40 parts by weight or more and 60 parts by weight or less, 40 parts by weight or more and 55 parts by weight or less based on 100 parts by weight of the acrylic resin. , 45 parts by weight or more and 60 parts by weight or less, or 45 parts by weight or more and 55 parts by weight or less.

Within the above range, the glass transition temperature of the acrylic resin can be controlled, and the adhesive film produced through this can secure high mechanical properties, high adhesive properties, and excellent workability even under extreme conditions of high temperature and high humidity.

In addition, by securing compatibility with the UV blocking agent included in the adhesive composition, even if the UV blocking agent is included, adhesive properties and mechanical properties are not reduced, so that excellent workability of the adhesive film can be maintained.

According to an exemplary embodiment of the present invention, the content of the polar functional group-containing monomeric polymerized unit is 0.1 parts by weight or more and 10 parts by weight or less, 0.1 parts by weight or more and 7 parts by weight or less, 5 parts by weight or more and 10 parts by weight based on 100 parts by weight of the acrylic resin. It may be not more than 5 parts by weight, or 5 parts by weight or more and 7 parts by weight or less.

Within the above range, it is possible to improve the chemical bonding strength between the constituent components in the adhesive composition containing the acrylic resin, thereby improving the adhesive strength of the adhesive film produced, and at the same time, it is possible to secure workability. Specifically, if it is less than the above range, there may be a problem in that sufficient adhesion to the adherend is not realized, and if it exceeds the above range, the adhesion to the adherend may be excessively increased, resulting in a problem of deteriorating workability. .

According to an exemplary embodiment of the present invention, the weight average molecular weight of the acrylic resin is 1,000,000 g/mol or more and 1,300,000 g/mol or less, 1,000,000 g/mol or more and 1,200,000 g/mol or less, 1,100,000 g/mol or more and 1,300,000 g/mol or less, Alternatively, it may be 1,100,000 or more and 1,200,000 g/mol or less.

Within the above range, high adhesion and excellent durability of the adhesive film made of the acrylic resin can be secured.

According to an exemplary embodiment of the present invention, the glass transition temperature of the acrylic resin is -30 °C to -5 °C, -30 °C to -10 °C, -20 °C to -5 °C, or -20 °C to- It may be less than or equal to 20 ℃.

Within the above range, since the acrylic resin has relatively flexible physical properties, reliability of an adhesive film made from the acrylic resin can be secured.

According to an exemplary embodiment of the present invention, the adhesive composition may include a thermosetting agent. Specifically, the adhesive composition may include the above-described acrylic resin and a thermosetting agent.

By including the heat curing agent, the adhesive composition may be heat-cured and then prepared into an adhesive film.

According to an exemplary embodiment of the present invention, the adhesive composition may not contain a photocuring agent. That is, the adhesive composition may not cause a crosslinking reaction between components contained therein by light irradiation.

Accordingly, the adhesive film including the cured product of the adhesive composition may not react even by UV irradiation, and variations in mechanical properties and adhesive properties can be minimized even by UV irradiation.

According to an exemplary embodiment of the present invention, the thermal curing agent may include at least one of an aziridine-based thermal curing agent, an isocyanate-based thermal curing agent, and an epoxy-based thermal curing agent, and preferably an aziridine-based thermal curing agent.

According to an exemplary embodiment of the present invention, the isocyanate-based thermal curing agent is an aliphatic isocyanate-based thermal curing agent, an alicyclic isocyanate-based thermal curing agent, an aromatic isocyanate-based thermal curing agent, a sulfur-containing aromatic isocyanate-based thermal curing agent, a sulfur-containing aliphatic isocyanate-based thermal curing agent, and a sulfur-containing compound. It may contain at least one of a cyclic aromatic isocyanate-based thermosetting agent. However, it is not limited thereto, and may be freely selected from isocyanate-based thermal curing agents known in the art.

According to an exemplary embodiment of the present invention, the aziridine-based thermosetting agent is N,N'-toluene-2,4-bis(1-aziridinecarboxamide), N,N'-diphenylmethane-4,4' -May contain at least one of bis(1-aziridinecarboxamide), triethylene melamine, bisisoprotaloyl-1-(2-methylaziridine) and tri-1-aziridinylphosphine oxide . However, the present invention is not limited thereto and may be freely selected as long as an aziridine-based thermal curing agent known in the art.

According to an exemplary embodiment of the present invention, the epoxy-based thermal curing agent is ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N,N,N',N'-tetraglycidyl It may contain at least one of ethylenediamine and glycerin diglycidyl ether. However, it is not limited thereto, and may be freely selected from epoxy-based thermosetting agents known in the art.

According to an exemplary embodiment of the present invention, the content of the thermosetting agent is 0.1 parts by weight or more and 1 part by weight or less, 0.1 parts by weight or more and 0.7 parts by weight or less, 0.3 parts by weight or more and 1 part by weight or less based on 100 parts by weight of the solid content of the acrylic resin. , 0.3 parts by weight or more and 0.7 parts by weight or less.

In the above range, durability and adhesive strength of the adhesive film prepared using the adhesive composition can be secured at the same time. Specifically, if it is less than the above range, there is a problem in that the adhesive film is not sufficiently cured, so that reliability of the adherend cannot be secured in an environment of high temperature and high humidity, and if it exceeds the above range, the adhesive film is excessively cured. There may be a problem that the adhesive strength of the decreases.

According to an exemplary embodiment of the present invention, the adhesive composition may include a sunscreen. That is, the adhesive composition may include the acrylic resin, the heat curing agent, and a sunscreen.

According to an exemplary embodiment of the present invention, since the adhesive composition includes the sunscreen agent, the adhesive film including the cured product of the adhesive composition may implement UV-blocking properties. As the adhesive film secures UV blocking properties, there is an advantage of minimizing the modification of the polymer dispersed liquid crystal contained in the conductive film attached to the base film through UV irradiation through this.

In addition, the UV blocking property of the adhesive film may be quantified by light transmittance at a specific wavelength to be described later.

According to an exemplary embodiment of the present invention, the sunscreen agent may be at least one of an oxanilide-based compound, a benzophenone-based compound, a benzotriazole-based compound, and a triazine-based compound, and specifically, the triazine-based compound is hydroxyphenyl It may be an -S-triazine-based compound.

In particular, when the adhesive composition contains the hydroxyphenyl-S-triazine-based compound as a UV blocking agent, the adhesive film including the cured product of the adhesive composition can maintain excellent adhesive properties and excellent mechanical durability, and at the same time There is an advantage of securing blocking characteristics.

According to an exemplary embodiment of the present invention, the oxanilide-based compound is 4,4'-dioctyloxyoxanilide, 2,2'-diethoxyoxanilide, 2,2'-dioctyloxy-5, 5'-di-tert-butoxanilide, 2,2'-didodecyloxy-5,5'-di-tert-butoxanilide, 2-ethoxy-2'-ethyloxanilide, N,N '-Bis(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2'-ethoxyanilide and their 2-ethoxy-2'-ethyl-5,4'-di- It may be at least one of a mixture with tert-butoxanilide, a mixture of o- and p-methoxy-disubstituted oxanilide, and a mixture of o- and p-ethoxy-disubstituted oxanilide. However, the present invention is not limited thereto, and may be freely selected from oxanilide compounds known in the art.

According to an exemplary embodiment of the present invention, the benzophenone-based compound is benzophenone, benzhydrol, 4-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone , 2,2'-dihydroxy-4-methoxybenzophenone and 2,3,4-trihydroxybenzophenone may be at least one. However, it is not limited thereto, and may be freely selected from benzophenone-based compounds known in the art.

According to an exemplary embodiment of the present invention, the benzotriazole-based compound is 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole and N-[3-benzotriazole-2 It may be at least one of -yl-2-hydroxy-5-(1,1,3,3-tetramethylbutyl)-benzyl]-2-methylacrylamide. However, it is not limited thereto, and may be freely selected from benzotriazole-based compounds known in the art.

According to an exemplary embodiment of the present invention, the hydroxyphenyl-S-triazine-based compound is 2,6-bis-(2,4-dimethylphenyl)-4-(2-hydroxy-4-octyloxyphenyl)- s-triazine; 2,6-bis-(2,4-dimethylphenyl)-4-(2,4-dihydroxyphenyl)-s-triazine; 2,4-bis(2,4-dihydroxyphenyl)-6-(4-chlorophenyl)-s-triazine; 2,4-bis[2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(4-chlorophenyl)-s-triazine; 2,4-bis[2-hydroxy-4-(2-hydroxy-4-(2-hydroxyethoxy)phenyl]-6-(2,4-dimethylphenyl)-s-triazine; 2, 4-bis[2-hydroxy-4-(2-hydroxyethoxy)-phenyl]-6-(4-bromophenyl)-s-triazine; 2,4-bis[2-hydroxy-4 -(2-acetoxyethoxy)phenyl]-6-(4-chlorophenyl)-s-triazine; And 2,4-bis(2,4-dihydroxyphenyl)-6-(2,4- It may be at least one of dimethylphenyl)-s-triazine.

According to an exemplary embodiment of the present invention, the content of the sunscreen agent is 0.1 parts by weight or more and 10 parts by weight or less, 0.1 parts by weight or more and 7 parts by weight or less, 0.1 parts by weight or more and 5 parts by weight or less based on 100 parts by weight of the solid content of the acrylic resin. , 0.5 parts by weight or more and 10 parts by weight or less, 0.5 parts by weight or more and 7 parts by weight or less, 0.5 parts by weight or more and 5 parts by weight or less, 1 part by weight or more and 10 parts by weight or less, 1 part by weight or more and 7 parts by weight or less, or 1 part by weight It may be more than 5 parts by weight or less.

Within the above range, the UV blocking agent included in the adhesive composition can increase compatibility with the acrylic resin, thereby providing an adhesive film having workability, reliability in extreme conditions of high temperature and high humidity, and UV blocking property. I can. Specifically, when it exceeds the above range, there may be a problem in that optical visibility is deteriorated.

According to an exemplary embodiment of the present invention, the adhesive composition may further include a solvent. That is, the adhesive composition may include an acrylic resin, a heat curing agent, a sunscreen agent, and a solvent. In addition, the type of the solvent is not particularly limited, and may be appropriately selected from types of solvents generally known in the art for preparing the adhesive composition.

According to an exemplary embodiment of the present invention, the adhesive composition may further include a solvent, thereby implementing an appropriate viscosity for coating with an adhesive film.

Another embodiment of the present invention provides an adhesive film.

An exemplary embodiment of the present invention provides an adhesive film comprising a cured product of the adhesive composition.

According to an exemplary embodiment of the present invention, the adhesive film may include a thermosetting product of the adhesive composition.

In addition, according to an exemplary embodiment of the present invention, the adhesive composition may not be photocured even when irradiated with light.

According to an exemplary embodiment of the present invention, the adhesive film may be formed by inducing a crosslinking reaction by applying heat to the adhesive composition and curing, that is, heat curing. As a method for forming the adhesive film by thermally curing the adhesive composition, a thermosetting method known in the art may be used.

According to an exemplary embodiment of the present invention, the light transmittance at a wavelength of 380 nm of the adhesive film may be 5% or less. That is, the adhesive film may have a transmittance of 5% or less of light having an ultraviolet wavelength region, which may mean that the adhesive film has a light blocking ratio of 95% or more having an ultraviolet wavelength region.

In the present specification, the term "light transmittance" may mean that when light having a specific wavelength is irradiated to an irradiated object, the amount of light transmitted through the irradiated object is expressed as a percentage with respect to the amount of light irradiated to the irradiated object. have. That is, the "light transmittance at a wavelength of 380 nm" may mean a percentage of the amount of light transmitted through the irradiated object to the amount of light irradiated to the irradiated object of light having a wavelength of 380 nm.

Another embodiment of the present invention provides a smart window.

An exemplary embodiment of the present invention is an electrochromic film comprising a polymer dispersed liquid crystal layer, and a conductive layer provided on both surfaces of the polymer dispersed liquid crystal layer; And a window substrate, wherein the window substrate and the electrochromic film are attached through the adhesive film to provide a smart window.

According to an exemplary embodiment of the present invention, the smart window may be one in which an electrochromic film, an adhesive film, and a window substrate are sequentially provided.

According to an exemplary embodiment of the present invention, the electrochromic film may include a polymer dispersed liquid crystal layer, and may include a conductive layer. In addition, the conductive layer may be provided on both sides of the polymer dispersed liquid crystal layer.

According to an exemplary embodiment of the present invention, the conductive layer comprises metal oxides such as indium tin oxide (ITO), antimony-doped zinc oxide (AZO), antimony-doped tin oxide (ATO), SnO, RuO ₂ , and IrO ₂ It may include, but can form an electric field for controlling the alignment of the liquid crystal, can supply electric charge, and is excellent in adhesion to the adhesive film, it may be selected without limitation, as long as it is known in the art.

According to an exemplary embodiment of the present invention, the polymer dispersed liquid crystal layer may be formed by dispersing a micrometer-sized liquid crystal in a polymer matrix, and the liquid crystal and the polymer are phase separated from a mixture containing the polymer and the liquid crystal. It may be distributed by.

According to an exemplary embodiment of the present invention, the polymer dispersed liquid crystal layer may include Polymer Network Liquid Crystal (PNLC) or Polymer Stabilized Liquid Crystal (PSLC).

According to an exemplary embodiment of the present invention, the window substrate is polyethylene terephthalate (PET), triacetyl cellulose (TAC), cyclic olefin polymer (Cyclo Olefin Polymer; COP), poly(methyl methacrylate). ) {Poly(methyl methacrylate); PMMA}, polycarbonate (PC), polyethylene (Poly Ethylene; PE), polypropylene (PP), polyvinyl acetate (PVA), polyether sulfone (PES), It may contain at least one of polyethylene imide (PEI) and polyimide (PI). However, the present invention is not limited thereto, and may be freely selected from plastic films that can implement bending properties and have high UV transmittance.

When the smart window is provided with an electrochromic film, an adhesive film, and a window substrate sequentially as described above, when ultraviolet rays are irradiated from the window substrate toward the adhesive film, due to the UV blocking property of the adhesive film, irradiation is performed. Ultraviolet rays may be blocked by the adhesive film, thereby minimizing damage to the polymer dispersed liquid crystal layer included in the electrochromic film.

According to an exemplary embodiment of the present invention, the adhesive force of the adhesive film to the electrochromic film may be greater than that of the adhesive film to the window substrate.

Accordingly, even if the adhesive film is peeled from the window substrate, it may be peeled off while minimizing the residuals of the adhesive film appearing on the window substrate.

Hereinafter, examples will be described in detail in order to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various forms, and the scope of the present invention is not construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely describe the present invention to those of ordinary skill in the art.

< Manufacturing example >

Manufacturing example One

As a monomer, a composition containing 40 parts by weight of 2-ethylhexyl acrylate, 55 parts by weight of methyl acrylate, and 5 parts by weight of acrylic acid was polymerized to prepare an acrylic resin.

The weight average molecular weight of the acrylic resin was 1,200,000 g/mol, and the glass transition temperature was -15°C.

Manufacturing example 2

As a monomer, a composition containing 45 parts by weight of 2-ethylhexyl acrylate, 50 parts by weight of methyl acrylate, and 5 parts by weight of acrylic acid was polymerized to prepare an acrylic resin.

The weight average molecular weight of the acrylic resin was 1,200,000 g/mol, and the glass transition temperature was -19°C.

Manufacturing example 3

As a monomer, a composition containing 65 parts by weight of 2-ethylhexyl acrylate, 25 parts by weight of methyl acrylate, and 10 parts by weight of acrylic acid was polymerized to prepare an acrylic resin.

The weight average molecular weight of the acrylic resin was 1,200,000 g/mol, and the glass transition temperature was -29°C.

< Example And Comparative example >

Example One

Adhesive comprising the acrylic resin according to Preparation Example 1 and about 2 parts by weight of a hydroxy-S-triazine-based sunscreen (Tinuvin 477, manufactured by BASF) and about 2 parts by weight of an aziridine-based thermal curing agent based on 100 parts by weight of the solid content of the acrylic resin The composition was prepared.

Example 2

A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the acrylic resin according to Preparation Example 2 was included.

Comparative example One

A pressure-sensitive adhesive composition containing only the acrylic resin according to Preparation Example 1 was prepared.

Comparative example 2

A pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the acrylic resin according to Preparation Example 3 was included.

Comparative example 3

A pressure-sensitive adhesive composition containing only the acrylic resin according to Preparation Example 3 was prepared.

< Experimental example And evaluation>

The adhesive composition according to Examples 1 to 2 and Comparative Examples 1 to 3 was cured at a temperature of about 80° C. to 110° C. for about 1.5 minutes to prepare an adhesive film having a thickness of 25 μm and a polyethylene film having a thickness of 50 μm. An adhesive tape laminated on both sides of a terephthalate (PET) substrate was prepared, and the evaluation results of physical properties thereof are shown in Table 1 below.

division Constructability responsibility UV protection Example 1 ○ ○ ○ Example 2 ○ ○ ○ Comparative Example 1 ○ ○ X Comparative Example 2 X ○ ○ Comparative Example 3 X ○ X

Constructability evaluation

After spraying a surfactant on a 35 cm X 30 cm (width X length), thickness 1.1 T glass substrate with no printing step, the cut into 25 cm X 30 cm (width X length) on the glass substrate The adhesive tape and ITO (Indium Tin Oxide) film were sequentially laminated. When the adhesive tape and the ITO film were peeled off, the case where the adhesive tape and the ITO film were easily peeled off and no residue of the adhesive tape remained on the glass substrate was evaluated as ○, and the case where the adhesive tape and the ITO film remained on the glass substrate was evaluated as X. .

Reliability evaluation

The prepared adhesive tape was attached to the hard-coated PET film, and a 0.55 T-thick glass substrate was laminated thereon. In addition, the case where bubbles were generated after being introduced into the thermo-hygrostat under the conditions of 85°C and 85 RH% was evaluated as X, and the case where no bubbles were generated between the glass substrates was evaluated as ?.

UV blocking evaluation

After attaching the adhesive tape on a 1.1 T-thick glass substrate that does not have a printing step, irradiation with ultraviolet rays having a wavelength of 250 ~ 1,000 nm using a UV-Vis spectrometer at a temperature condition of about 20 ~ 30 ℃, transmittance Was measured, and if the light transmittance at a wavelength of 385 nm was 5% or less, it was evaluated as ○, and if it exceeded 5%, it was evaluated as X.

According to Table 1, Examples 1 and 2 including an acrylic resin and a UV blocking agent prepared according to an exemplary embodiment of the present invention are excellent in both workability, reliability under extreme conditions of high temperature and high humidity, and UV blocking properties. I could confirm.

On the other hand, Comparative Example 1, which does not contain a sunscreen, has relatively excellent workability and reliability, but has a problem in that it does not secure UV-blocking properties. Accordingly, it was confirmed that the adhesive composition according to an exemplary embodiment of the present invention must include the above-described sunscreen.

In addition, in the case of Comparative Example 2 containing an acrylic resin outside the content range of the (meth) acrylate monomer polymerization unit according to an exemplary embodiment of the present invention, by including a UV blocking agent, UV blocking properties can be secured, but the glass substrate It was confirmed that there is a problem in that the workability is inferior because the residue of the adhesive tape remains on the glass substrate due to the increase in adhesion with

Further, unlike Comparative Example 2 of the present invention, in the case of Comparative Example 3 that did not contain a sunscreen, it was confirmed that only reliability under extreme conditions was secured, and reliability and UV blocking properties were not excellent.

According to the evaluation results of Comparative Examples 2 and 3, there is a problem in that the workability is deteriorated when the blending ratio of the acrylic resin, specifically, the content of the polar functional group-containing monomer such as acrylic acid contained therein is increased, so that the blending of the acrylic resin is It was confirmed that it should be adjusted to a range according to an exemplary embodiment of the present invention.

That is, when the above results are summarized, in order to block UV, a sunscreen must be included, and in order to maintain the adhesive properties in an excellent state, the blending composition of the acrylic resin included in the adhesive composition is determined according to an exemplary embodiment of the present invention. It can be seen that it should be adjusted to the range.

Claims (12)

An acrylic resin comprising a linear alkyl group-containing (meth)acrylate monomer polymerization unit, a branched chain alkyl group-containing (meth)acrylate monomer polymerization unit, and a polar functional group-containing monomer polymerization unit; Heat curing agent; And a sunscreen agent,
The content of the linear alkyl group-containing (meth)acrylate monomer polymerized unit is 40 parts by weight or more and 60 parts by weight or less based on 100 parts by weight of the acrylic resin,
The content of the branched-chain alkyl group-containing (meth)acrylate monomer polymerized unit is 30 parts by weight or more and 50 parts by weight or less based on 100 parts by weight of the acrylic resin. The method according to claim 1,
The sunscreen is an adhesive composition comprising at least one compound of an oxanilide-based compound, a benzophenone-based compound, a benzotriazole-based compound, and a triazine-based compound. The method according to claim 1,
The amount of the sunscreen is 0.1 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the solid content of the acrylic resin. delete The method according to claim 1,
The content of the polar functional group-containing monomer polymerization unit is 0.1 parts by weight or more and 10 parts by weight or less based on 100 parts by weight of the acrylic resin. The method according to claim 1,
The content of the thermosetting agent is 0.1 parts by weight or more and 1 part by weight or less based on 100 parts by weight of the solid content of the acrylic resin. The method according to claim 1,
The thermosetting agent is an aziridine-based thermosetting agent, an isocyanate-based thermosetting agent, and an epoxy-based thermosetting agent comprising at least one of the adhesive composition. The method according to claim 1,
The weight average molecular weight of the acrylic resin is 1,000,000 g/mol or more and 1,300,000 g/mol or less. The method according to claim 1,
The glass transition temperature of the acrylic resin is -30 °C to -5 °C or less. An adhesive film comprising a cured product of the adhesive composition according to claim 1. The method of claim 10,
The adhesive film that the light transmittance at a wavelength of 380 nm of the adhesive film is 5% or less. An electrochromic film including a polymer dispersed liquid crystal layer and a conductive layer provided on both surfaces of the polymer dispersed liquid crystal layer; And a window base; including,
The window substrate and the electrochromic film is a smart window that is attached through the adhesive film according to claim 10.