KR101293887B1 - Photocurable adhesive compositon - Google Patents

Abstract

The present invention relates to a photocurable adhesive composition, a polarizing plate, and a liquid crystal display device. In the present invention, an adhesive excellent in physical properties such as water resistance, heat resistance and adhesiveness is provided. The present invention provides a photocurable adhesive composition capable of effectively adhering adherends having different physical properties to each other, for example, by attaching a film having low moisture permeability to a polarizer or attaching a hydrophobic functional film to a hydrophilic polarizer. , A polarizing plate and a liquid crystal display device can be provided.

Description

Photocurable adhesive composition {Photocurable adhesive compositon}

The present invention relates to a photocurable adhesive composition, a polarizing plate and a liquid crystal display device.

A polarizing plate is one of the optical components which comprise a liquid crystal display device. A polarizing plate is normally applied to a liquid crystal display device in the structure which laminated | stacked the protective film on the polarizer.

The polarizer may have a structure in which a protective film is laminated on one or both surfaces thereof, or in some cases, a layer having a function of a protective film and an additional optical function may be laminated on one surface of the polarizer.

Typically, the polarizer is prepared by treating a uniaxially stretched resin film, mainly a polyvinyl alcohol-based film, dyed with a dichroic dye with boric acid, or the like after washing with water, and drying after washing with water and drying. The film is attached. As a protective film for polarizers, a triacetyl cellulose (TAC) type | system | group film is used most often, and an aqueous polyvinyl alcohol-type adhesive agent is frequently used for the adhesion.

By the way, since a triacetyl cellulose film has high water vapor transmission rate, the polarizing plate containing the above easily deteriorates on high temperature or high humidity conditions. Accordingly, there is an attempt to use a film having a low moisture permeability compared to a triacetyl cellulose film, for example, a thermoplastic saturated norbornene-based resin film (eg, Patent Document 1, etc.), in addition to an amorphous polyolefin film, polyester Attempts have been made to use an acrylic resin film, an acrylic resin film, a polycarbonate resin film, a polysulfone resin film, an alicyclic polyimide resin film, or a cyclic olefin (COP) resin film or the like (ex. Document 2, etc.).

However, it is common that such a film has low water vapor permeability and shows hydrophobicity compared with a triacetyl cellulose type film. Accordingly, when the film is attached to a polarizer having hydrophilicity using an existing aqueous adhesive, for example, an aqueous polyvinyl alcohol-based aqueous solution or the like, there is a problem in that sufficient adhesive strength is not obtained or appearance is poor.

Japanese Patent Application Laid-Open No. 06-51117 Japanese Patent No. 4306270

An object of the present invention is to provide a photocurable adhesive composition, a polarizing plate, and a liquid crystal display device.

The present invention, as a means for solving the above problems, a polymer having a hydrophilic moiety and a reactive functional group, epoxy acrylate and

It provides a photocurable adhesive composition comprising a curing agent having a functional group capable of reacting with the reactive functional group.

The present invention is another means for solving the above problems, a polarizer; An adhesive layer formed on one or both surfaces of the polarizer and including a cured product of the adhesive composition of the present invention; And it provides a polarizing plate having a protective film attached to the polarizer via the adhesive layer.

As another means for solving the above problems, the present invention provides a liquid crystal display device comprising a liquid crystal panel having a polarizing plate according to the present invention attached to one side or both sides.

In the present invention, an adhesive excellent in physical properties such as water resistance, heat resistance and adhesiveness is provided. The present invention provides an adhesive composition, a polarizing plate, and the like, which can effectively adhere adherends having different physical properties to each other, for example, by attaching a film having low moisture permeability to a polarizer or a film having hydrophobicity to a hydrophilic polarizer. A liquid crystal display device can be provided.

The present invention provides a polymer having a hydrophilic moiety and a reactive functional group; Epoxy acrylate; And a curing agent having a functional group capable of reacting with the reactive functional group.

EMBODIMENT OF THE INVENTION Hereinafter, the adhesive composition of this invention is demonstrated in detail.

Hereinafter, in this specification, the term "alkyl", "alkoxy", "alkylene" or "alkylene oxide" is 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms or 1 to 4 carbon atoms. Straight or branched chain of; Or cyclic or acyclic alkyl, alkoxy, alkylene or alkylene oxide, and such alkyl, alkoxy, alkylene or alkylene oxide may be optionally substituted by one or more substituents.

In addition, in this specification, the term "alkenylene" or "alkynylene" is a straight or branched chain having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms, or 2 to 4 carbon atoms; Or cyclic or acyclic alkenylene or alkynylene, and such alkenylene or alkynylene may be optionally substituted with one or more substituents.

In the present specification, the term "arylene" means a bivalent moiety derived from an aromatic ring compound or including the compound in a skeleton, and specifically, 6 to 22, 6 to It can mean a divalent moiety derived from or comprising in the backbone an 18-membered, 6- to 14-membered or 6- to 10-membered aromatic ring compound, wherein such arylene is optionally substituted by one or more substituents. It may be substituted.

In addition, the term "bivalent heterocyclic moiety" in the present specification means a divalent moiety derived from a heterocyclic compound or comprising the compound in the skeleton, and specifically 3- to 22-membered, 3- to 18 It can mean a divalent moiety, derived from or containing in the skeleton, a 3 to 14 or 3 to 10 membered heterocyclic compound, wherein such a divalent moiety is optionally substituted by one or more substituents. It may be substituted.

In addition, the term "heterocyclic compound or heterocyclic moiety" herein refers to one or more carbon atoms; And a cyclic compound or a moiety derived therefrom, comprising at least one hetero atom selected from nitrogen (N), sulfur (S) and oxygen (O), specifically derived from aromatic or non-aromatic ring compounds , 3- to 22-membered, 3- to 18-membered, 3- to 14-membered, or 3- to 10-membered cyclic compound or a residue derived therefrom, and the compound or residue may be optionally substituted with one or more substituents. It may be substituted by.

In the definitions of the above terms, examples of substituents that may be substituted with alkyl, alkoxy, alkylene, alkylene oxide, alkenylene, alkynylene, arylene, heterocyclic moieties or heterocyclic compounds, etc., are generally applied in the chemical field. All substituents are included, and specifically include, but are not limited to, thiols, amines, amides, halogens, hydroxy, carboxy, glycidyl, cyano, nitro, heterocyclic moieties or aryl, and the like.

In addition, the expression "(C _nm ) alkyl, (C _nm ) alkoxy, (C _nm ) alkylene, (C _nm ) alkylene oxide, (C _nm ) alkenylene or (C _nm ) alkynylene)" is used herein. May mean alkyl, alkoxy, alkylene, alkylene oxide, alkenylene or alkynylene consisting of n to m carbon atoms.

In the present specification, the expression of "n-membered m-membered arylene, n-membered m-membered divalent heterocyclic moiety, n-membered m-membered heterocyclic moiety or n-membered m-membered heterocyclic compound" is n to n. It may mean a compound consisting of m ring-membered atoms or a residue containing such a compound.

In addition, the term "photocurable adhesive composition" used herein refers to an adhesive composition that can be cured by irradiation of electromagnetic waves, wherein the electromagnetic waves are microwaves, infrared (IR), ultraviolet (UV), X-ray and As well as gamma rays, it is used as a generic term for particle beams such as α-particle beams, proton beams, neutron beams, and electron beams.

In addition, in this specification, the term "solvent-free adhesive composition" means an adhesive composition in which the composition does not include a solvent such as an aqueous or organic solvent, and a volatilization step of the solvent is not required in the formation of the adhesive.

The adhesive composition of the present invention includes a polymer containing a hydrophilic moiety and a reactive functional group.

The hydrophilic moiety in the polymer of the present invention can impart excellent adhesion to the hydrophilic adherend to the adhesive of the present invention through interaction with the hydrophilic adherend. In the present invention, the hydrophilic moiety is bonded directly or via a suitable linker (ex. Alkylene, alkylene oxide, alkenylene, alkynylene, divalent heterocyclic moiety or arylene, etc.) to the polymer backbone. There may be.

The specific kind of hydrophilic moiety included in the polymer of the present invention is not particularly limited, and may be, for example, a heterocyclic moiety. In addition, in the present invention, specific types of heterocyclic moieties that may be included in the polymer are not particularly limited as long as they exhibit hydrophilicity. For example, aziridine moieties, azirine moieties, azetidine ) Residues, diazetidine residues, pyrrolidine residues, pyrroline residues, pyrrole residues, imidazolidine residues, pyrazolidine residues, already Imidazole residues, imidazoline residues, pyrazole residues, triazole residues, tetrazole residues, oxazolidine residues, pyrrolidone residues , Pyrazolone residues, pyrazolinone residues, imidazolidone residues, succinimide residues, maleimide residues, piperidine residues, piperazine (piperazine) residues, morpholine residues, jade Oxazine residues, piperidone residues, piperidinedione residues, piperazinedione residues, valerolactam residues, azepane residues, azepine It may be a mixture of one or more kinds of residues, diazepine residues, carprolactam residues, azocane residues or propiolactam residues.

In the present invention, Preferably, the heterocyclic moiety, a 3 to 8 membered heterocyclic moiety containing nitrogen (N) and oxygen (O) as a hetero atom; Or a 3-8 membered heterocyclic moiety containing nitrogen (N) as a hetero atom and substituted with an oxo (═O) group. Specific examples of such heterocyclic residues include oxazolidine residues, pyrrolidone residues, pyrazolone residues, pyrazolidone residues, imidazolidone residues, succinimide residues, maleimide residues, morpholin residues and oxazines. Residues, piperidone residues, piperidindione residues, piperazinedione residues, valerolactam residues, caprolactam residues or propiolactam residues, and the like, and more preferred examples thereof include pyrrolidone residues, pyrazolone residues, Pyrazolidone residues, imidazolidone residues, succinimide residues, maleimide residues, piperidone residues, piperidinedione residues, piperazinedione residues or valerolactam residues, and more preferred examples thereof include And include, but are not limited to, a rolidone residue, a pyrazolone residue, a pyrazolidone residue, an imidazolidone residue, a succinimide residue or a maleimide residue.

The polymer of the present invention may further include one or more hydrophilic residues in addition to the heterocyclic residues. In this case, specific examples of hydrophilic residues that may be included are not particularly limited, and for example, carboxyl group, hydroxy group, alkoxy, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkyloxycarbonyl, It may be one kind or a mixture of two or more of alkylaminoalkyloxycarbonyl, dialkylaminoalkyloxycarbonyl or alkylcarbonyloxy. In the present invention, such hydrophilic residues, like heterocyclic residues, may be directly or appropriate linkers (ex. Alkylene, alkylene oxides, alkenylene, alkynylene, divalent heterocyclic residues) in the polymer backbone or Arylene and the like).

Alkoxy in the above may be preferably (C _1-4 ) alkoxy, more preferably methoxy or ethoxy. In addition, the alkylaminocarbonyl or dialkylaminocarbonyl in the above is preferably (C _1-4 ) alkylaminocarbonyl or di (C _1-4 ) alkylaminocarbonyl, more preferably dimethylaminocarbon Nyl or t-butylaminocarbonyl and the like. In the above, aminoalkyloxycarbonyl, alkylaminoalkyloxycarbonyl and dialkylaminoalkyloxycarbonyl are preferably amino (C _1-4 ) alkyloxycarbonyl, (C _1-4 ) alkylamino ( C _1-4 ) alkyloxycarbonyl or di (C _1-4 ) alkylamino (C _1-4 ) alkyloxycarbonyl, more preferably aminoethyloxycarbonyl, methylaminoethyloxycarbonyl or dimethylamino Ethyloxycarbonyl and the like. In addition, the alkylcarbonyloxy in the above may preferably be (C _1-4 ) alkylcarbonyloxy, more preferably methylcarbonyloxy.

In the polymers of the invention, the hydrophilic residues which may be further included in the heterocyclic moiety are preferably aminocarbonyl, (C _1-4 ) alkylaminocarbonyl, di (C _1-4 ) alkylaminocarbonyl, amino (C _1-4 ) alkyloxycarbonyl or (C _1-4 ) alkylcarbonyloxy, more preferably (C _1-4 ) alkylcarbonyloxy.

The polymers of the present invention also include reactive functional groups. In the present invention, the term "reactive functional group" means a functional group which has reactivity with a functional group or a residue contained in a curing agent described later and can introduce a polymer into an adhesive matrix after curing. The polymer having a hydrophilic moiety and a reactive functional group at the same time can impart excellent adhesive properties, water resistance and heat resistance to various adherends to the adhesive.

The kind of reactive functional group that can be included in the polymer in the present invention is not particularly limited as long as it is appropriately selected so as to react with the functional group or moiety included in the curing agent described later. For example, the reactive functional group may be a hydroxy group, a carboxyl group, a cyclic ether group (ex. Glycidyl group or oxetane group, etc.), an amine group (ex. Amino group, alkylamino group or dialkylamino group, etc.), (meth) And a kind or a mixture of two or more kinds such as an acryloyl group or a (meth) acryloyloxy group, and preferably a hydroxy group, a carboxyl group, or a glycidyl group, and more preferably, a hydroxy group, a carboxyl group, and a glycidyl group. Two or more functional groups of the dill may be, but are not limited thereto. In the present invention, the reactive functional group may be linked to the main chain directly or through an appropriate linker similarly to the case of the hydrophilic residue.

The content of the reactive functional group and the hydrophilic moiety in the polymer of the present invention is not particularly limited and may be appropriately controlled according to the application to be applied. The polymer of the present invention may include, for example, about 1 mol to 3 mol, preferably about 1 mol to 2 mol of hydrophilic moiety with respect to 1 mol of the reactive functional group. That is, the molar ratio of the hydrophilic moiety (reactive functional group: hydrophilic moiety) to the reactive functional group in the polymer of the present invention may be 1: 1 to 3, preferably 1: 1 to 2. In the present invention, the molar ratio of the reactive functional group and the hydrophilic moiety can be controlled in the above range so that the adhesive can have excellent adhesion, water resistance and heat resistance.

As long as the polymer contained in the adhesive composition of the present invention simultaneously contains a hydrophilic moiety and a reactive functional group, the specific structure thereof is not particularly limited.

In one example of the present invention, the polymer may include a repeating unit of Formula 1 and a repeating unit of Formula 2.

[Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2, R represents hydrogen or alkyl, A represents a hydrophilic moiety or a substituent including a hydrophilic moiety, and B represents a substituent including a reactive functional group or a reactive functional group.

In the repeating units of Formulas 1 and 2, R may preferably be hydrogen or (C _1-4 ) alkyl, more preferably hydrogen, methyl or ethyl.

In the repeating unit of Chemical Formula 1, A represents a substituent including a hydrophilic residue or a hydrophilic residue, and specific types of the hydrophilic residue are as described above.

In the present invention, the repeating unit of Formula 1 may be represented by, for example, the following Formula 3.

(3)

In Formula 3, R represents hydrogen or alkyl; L is a single bond, alkylene, alkylene oxide,-(CH ₂ ) _l -O- (CH ₂ ) _m- , Alkenylene, alkynylene, arylene or a divalent heterocyclic moiety, H represents a hydrophilic moiety, and l and m each independently represent an integer of 1 to 20.

In the definition of said L, "single bond" means the case where another atom does not exist in the site | part represented by L, and H is directly connected with the main chain.

In addition, in the definition of L, l and m, each independently, may be an integer of 1 to 15, preferably 1 to 10, more preferably 1 to 5.

In formula 3, L is preferably a single bond, (C _1-4) alkylene, _(C1-4) alkylene oxide, or _{- (CH 2) l -O- (} CH 2) m - (l, m may each independently be an integer of 1 to 4), and more preferably, may be a single bond or (C _1-4 ) alkylene.

In the present invention, as described above, the repeating unit of Formula 3 may be represented by, for example, the formula of any one of the following 4 to 11.

[Formula 4]

[Chemical Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

[Chemical Formula 9]

[Formula 10]

[Formula 11]

In Chemical Formulas 4 to 11, R and L are as defined in Chemical Formula 3, and R ₁ to R ₆ are each independently hydrogen or alkyl; R ₉ and R ₁₀ are each independently a carboxyl group or a hydroxyl group, P is an alkylene, and R ₇ and R ₈ are bonded to each other to form a heterocyclic moiety.

In the definition of Chemical Formulas 4 to 11, specific examples of R ₁ to R ₁₀ and P may be selected within a range that satisfies specific examples of the hydrophilic residues described above.

In the present invention, the repeating unit of Formula 2 may be represented by, for example, the following Formula 12.

[Chemical Formula 12]

In Formula 12, R and L are as defined in Formula 3, E represents a reactive functional group or a substituent including a reactive functional group.

More specific examples of the reactive functional group are as described above.

In the present invention, the repeating unit of Formula 9, for example, may be represented by the formula of any one of the following formulas 13 to 18.

[Chemical Formula 13]

[Formula 14]

[Formula 15]

[Chemical Formula 16]

[Chemical Formula 17]

[Chemical Formula 18]

In Formulas 13 to 18, L and R are as defined in Formula 12, P each independently represents a single bond or an alkylene, U represents a urethane bond, a urea bond, an amide bond, or an oxazolidone bond, R ₁₁ to R ₁₃ represent a reactive functional group, and R ₁₄ to R ₁₇ each independently represent hydrogen or alkyl.

In Formulas 13 to 18, more preferable types of L and R are as described above. In addition, in Chemical Formulas 13 to 18, P may preferably be a single bond or (C _1-8 ) alkylene, more preferably a single bond or (C _1-4 ) alkylene, and in Formula 13, U May preferably be a urethane bond. In addition, in Chemical Formulas 10 to 13, R ₁₁ to R ₁₃ may each independently represent the aforementioned reactive functional groups, for example, R ₁₁ may be a hydroxy group, a carboxyl group, or a cyclic ether group (ex. Dialkyl), R ₁₂ may be a carboxyl group, and R ₁₃ may be (meth) acryloyl or (meth) acryloyloxy. In addition, R ₁₄ to R ₁₇ may be each independently hydrogen or (C _1-4 ) alkyl.

In the polymer of the present invention, the content of the repeating units of Formulas 1 and 2 is not particularly limited and may be appropriately selected in consideration of the molar ratio of the hydrophilic residue and the reactive functional group and the application use. In one example of the present invention, the polymer may include 37 parts by weight to 77 parts by weight of the repeating unit of Formula 1 and 24 parts by weight to 64 parts by weight of the repeating unit of Formula 2, preferably, Formula 1 47 parts by weight to 67 parts by weight of the repeating unit and 34 parts by weight to 54 parts by weight of the repeating unit of Formula 2. In the present invention, the weight part of the repeating unit is applied in the polymerization process of the polymer, and means a weight ratio based on the weight of each monomer constituting the repeating unit.

The polymer of the present invention comprises only the above-mentioned repeating units of the formulas (1) and (2) or, if necessary, together with the repeating units of the above-mentioned formulas (1) and (2), the conventional monomer component (ex. Alkyl (meth) acryl) Other repeating units derived from an ethylenically unsaturated double bond containing monomer), including the rate and the like.

In the present invention, the polymer may have a weight average molecular weight (M _w ) of 20,000 to 120,000, preferably 20,000 to 60,000. Said "weight average molecular weight" means the polystyrene conversion value measured by GPC (Gel Permeation Chromatograohy). In the present invention, the weight average molecular weight can be controlled in the above range, so that the adhesive can exhibit excellent adhesive properties, peeling properties and durability.

The polymer of the present invention may have a glass transition temperature (T _g ) of about 10 ° C to 70 ° C, preferably about 20 ° C to 60 ° C. In the present invention, the glass transition temperature of the polymer can be controlled in the above range so that the adhesive can exhibit properties such as excellent adhesive properties and heat resistance.

In the present invention, the method for producing such a polymer is not particularly limited. In the present invention, for example, it is possible to prepare a monomer mixture by polymerizing monomers that can impart each of the above-mentioned repeating units to the polymer, and to polymerize them.

In this case, examples of the monomer capable of imparting the repeating unit of Chemical Formula 1 to the polymer include vinyl ether (ex. Methyl vinyl ether); (Meth) acrylamide; N-substituted (meth) acrylamides; N, N-substituted (meth) acrylamides; Vinyl acetate; Hydroxy group-containing monomers such as hydroxyalkyl (meth) acrylate and the like; (Meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyl acid, acrylic acid duplex, itaconic acid, maleic acid or Carboxyl group-containing monomers such as maleic anhydride and the like; Amine group-containing monomers such as (meth) acrylamide, aminoalkyl (meth) acrylate, alkylaminoalkyl (meth) acrylate or dialkylaminoalkyl (meth) acrylate, or heterocycles corresponding to the aforementioned heterocyclic residues The compound etc. which the compound is substituted by the vinyl group or the allyl group, etc. are mentioned, It is not limited to this.

In addition, examples of the monomer capable of imparting the repeating unit represented by Chemical Formula 2 to the polymer include hydroxy group-containing monomers such as hydroxyalkyl (meth) acrylate; Cyclic ether group-containing monomers such as glycidyl (meth) acrylate or glycidylalkyl (meth) acrylate; (Meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyl acid, acrylic acid duplex, itaconic acid, maleic acid or Carboxyl group-containing monomers such as maleic anhydride and the like; Or amine group-containing monomers such as (meth) acrylamide, aminoalkyl (meth) acrylate, alkylaminoalkyl (meth) acrylate or dialkylaminoalkyl (meth) acrylate, and the like, but are not limited thereto. . In addition, in the present invention, in order to introduce a functional group such as (meth) acryloyl or (meth) acryloyloxy or the like into the polymer, a hydroxyl group, a carboxyl group, an amine group or After introducing a glycidyl group or the like, a method of reacting the polymer with a compound having a (meth) acryloyl group or a (meth) acryloyloxy group and an isocyanate group can be used. In the above, examples of the compound having a (meth) acryloyl group or a (meth) acryloyloxy group and an isocyanate group simultaneously include 2-isocyanatoethyl (meth) acrylate; 1,1-bis (acryloyloxymethyl) ethyl isocyanate; (Meth) acryloyloxy ethyl isocyanate; Meta-isopropenyl-α, α-dimethylbenzyl isocyanate; (Meth) acryloyl isocyanate; Allyl isocyanate; An acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with 2-hydroxyethyl (meth) acrylate; Or acryloyl monoisocyanate compounds obtained by reacting a diisocyanate compound or a polyisocyanate compound, a polyol compound and 2-hydroxyethyl (meth) acrylate, and the like, but are not limited thereto.

In the present invention, a method of preparing a polymer using a mixture of such monomers is not particularly limited, and for example, a general polymerization method such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization or emulsion polymerization may be applied. . In the present invention, for example, a solution polymerization method may be used, and solution polymerization is preferably performed at a polymerization temperature of 50 ° C to 140 ° C by adding an initiator in a state where each monomer is uniformly mixed. Examples of initiators that can be used in this process include azo initiators such as azobisisobutyronitrile or azobiscyclohexane carbonitrile; And / or conventional initiators such as peroxides such as benzoyl peroxide or acetyl peroxide, and the like, but may be used one or a mixture of two or more thereof, but is not limited thereto.

The adhesive composition of this invention contains an epoxy acrylate. In the present invention, the epoxy acrylate can impart adhesive properties to the adhesive, it can impart heat resistance.

The kind of epoxy acrylate which can be used by this invention is not specifically limited, For example, the compound which added-reacted (meth) acrylic acid to an epoxy resin can be used.

Examples of the epoxy resins mentioned above include aromatic epoxy resins or aliphatic epoxy resins, and specifically, resorcinol diglycidyl ether, bisphenol A, bisphenol F, bisphenol S, bisphenol fluorene or an alkylene oxide adduct thereof. Novolak-type epoxy resins, such as di or polyglycidyl ether, a phenol novolak-type epoxy resin, and a cresol novolak-type epoxy resin of; Aromatic epoxy resins such as glycidylphthalimide or phthalic acid diglycidyl ester; Or polyalkylene glycols such as diglycidyl ethers of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol and 1,6-hexanediol, and diglycidyl ethers of polyethylene glycol and polypropylene glycol. Diglycidyl ether of diglycidyl ether, neopentyl glycol, dibromoneopentyl glycol and its alkylene oxide adducts, di or triglycidyl of trimethylol ethane, trimethylolpropane, glycerin and its alkylene oxide adducts Di or polyglycides of polyglycidyl ethers of polyhydric alcohols such as ethers, and di, tri or tetraglycidyl ethers of pentaerythritol and alkylene oxide adducts thereof, hydrogenated bisphenol A and alkylene oxide adducts thereof Aliphatic epoxy resins such as dill ether, tetrahydrophthalic acid diglycidyl ether, or hydroquinone diglycidyl ether, It is not to be limited to.

In the present invention, among the epoxy acrylates as described above, aromatic epoxy acrylates, preferably derived from an aromatic epoxy resin, may be used, and more preferably, bisphenol A epoxy acrylate may be used, but is not limited thereto.

In the adhesive composition of the present invention, the epoxy acrylate is 100 parts by weight to 1,000 parts by weight, preferably 300 parts by weight to 800 parts by weight, more preferably 300 parts by weight to 600 parts by weight, based on 100 parts by weight of the aforementioned polymer. It can be included as a wealth. In the present invention, by controlling the content of the epoxy acrylate in the above range, it is possible to maintain excellent physical properties such as heat resistance of the adhesive.

The adhesive composition of the present invention further comprises a curing agent, and the curing agent includes a functional group capable of reacting with a reactive functional group contained in the polymer described above. Such a curing agent may react with the polymer during the curing process to improve the water resistance of the adhesive.

Specific types of the curing agent that can be used in the present invention may be appropriately selected in consideration of the type of reactive functional groups contained in the polymer, for example, isocyanate compound, melamine compound, aziridine compound, amine compound, carboxyl system Compounds, aldehyde compounds, anhydride compounds, epoxy compounds or metal chelate compounds may be used.

In the present invention, particularly as the curing agent, a compound containing a carboxyl group or an aldehyde in a molecular structure, preferably a compound containing a carboxyl group and an aldehyde in a molecular structure can be used. In the case of the aldehyde contained in the above compound, a reactive functional group included in the polymer, for example, a hydroxy group and a hemi-acetal or acetal can be formed, and the carboxyl group is included in the polymer. Reacts with functional groups such as glycidyl groups to increase the degree of cure of the adhesive and to improve water and heat resistance.

Specific examples of preferred curing agents that can be used in the present invention include aldehyde or dialdehyde compounds such as glutaraldehyde, malondialdehyde or phthalaldehyde; Monocarboxylic or dicarboxylic acid compounds such as oxalic acid, malonic acid, succinic acid, glutaric acid or phthalic acid; Or a compound containing an aldehyde and a carboxyl group, such as phenyl glyoxylic acid or glyoxylic acid, but is not limited thereto.

In the present invention, the curing agent may be included in the composition at 100 parts by weight to 500 parts by weight, preferably 300 parts by weight to 500 parts by weight, more preferably 300 parts by weight to 400 parts by weight, based on 100 parts by weight of the polymer. In the present invention, by controlling the content of the curing agent in the above range, it is possible to provide an adhesive having more excellent water resistance and heat resistance.

The adhesive composition of the present invention may further include a monomer component. The monomer component allows to adjust the viscosity of the adhesive composition, to form an adhesive layer having a uniform thickness and physical properties, and can also be inserted into the adhesive matrix through a curing reaction.

The specific kind of the monomer component which can be used in the present invention is not particularly limited, and for example, alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms such as methyl (meth) acrylate or ethyl (meth) acrylate, etc. ; Hydroxy group-containing monomers such as hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate; Carboxyl group-containing monomers such as (meth) acrylic acid or β-carboxyethyl (meth) acrylate; Alkoxy group-containing monomers such as 2- (2-ethoxyethoxy) ethyl (meth) acrylate and the like; Polyfunctional acrylates such as hexanediol diacrylate or ethylene glycol dimethacrylate; Aromatic group-containing monomers such as phenoxyethyl (meth) acrylate; Or heterocyclic residue-containing monomers such as tetrahydrofurfuryl (meth) acrylate or (meth) acryloyl morpholine, or the like, or two or more thereof. have.

In the present invention, it is preferable to use a monomer having a polar group such as a hydroxy group, a carboxyl group, an alkoxy group or a heterocyclic moiety to exhibit hydrophilicity, and more preferably a monomer containing a hydroxy group or a heterocyclic moiety. Can be used. Such monomers can further improve the adhesive properties of the adhesive of the present invention to the hydrophilic adherend through interaction with the hydrophilic adherend.

In the present invention, the monomer component may be included in the composition at 1,000 parts by weight to 5,000 parts by weight, preferably 1,000 parts by weight to 3,000 parts by weight, more preferably 2,000 parts by weight to 3,000 parts by weight, based on 100 parts by weight of the polymer. In the present invention, the content of the monomer component can be adjusted to the above range, so that the adhesive can exhibit better adhesive properties.

The adhesive composition of the present invention may further include a photoinitiator. The kind of photoinitiator that can be used in the present invention is not particularly limited, and for example, an initiator such as benzoin, hydroxyketone, aminoketone or phosphine oxide may be used, and more specifically, benzoin , Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylanino acetophenone, 2,2-dimethoxy-2-phenylaceto Phenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4 -(Methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzo Phenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthra Quinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chloro thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p -Dimethylamino benzoic acid ester, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like Can be used. In the present invention, one or more of the above may be used, but is not limited thereto.

In the adhesive composition of the present invention, the photoinitiator may be included in an amount of 100 parts by weight to 500 parts by weight, preferably 100 parts by weight to 300 parts by weight, and more preferably 100 parts by weight to 200 parts by weight, based on 100 parts by weight of the polymer. By controlling the content of the photoinitiator in the above range, it is possible to induce an efficient curing reaction, and to prevent problems such as degradation of adhesive properties due to the remaining components after curing.

The adhesive composition of the present invention may further include a thermal initiator. The thermal initiator may promote a curing reaction of the adhesive composition, and may further improve heat resistance, water resistance, adhesive properties, and the like of the adhesive.

The kind of thermal initiator that can be used in the present invention is not particularly limited, and for example, conventional initiators such as peroxide-based, azo-based or redox-based initiators can be used, and preferably peroxide-based. Initiators can be used.

Examples of the peroxide initiators include inorganic peroxides such as potassium peroxide, ammonium persulfate or hydrogen peroxide; Or benzoyl peroxide (BPO), diacyl peroxide (ex. Dilauroyl peroxide (Luperox LP)), peroxy dicarbonate, peroxy ester, tetramethylbutylperoxy neodecanoate (ex. Perocta ND , NOF company (made)), bis (4-butylcyclohexyl) peroxydicarbonate (ex. Peroyl TCP, NOF company made), di (2-ethylhexyl) peroxy carbonate, butyl peroxy neodecanoate (ex. Perbutyl ND, NOF Co., Ltd.), dipropyl peroxy dicarbonate (ex. Peroyl NPP, NOF Co., Ltd.), diisopropyl peroxy dicarbonate (ex. Peroyl IPP, NOF Co., Ltd.) ), Diethoxyethyl peroxy dicarbonate (ex. Peroyl EEP, NOF Co., Ltd.), diethoxyhexyl peroxy dicarbonate (ex. Peroyl OEP, NOF Co., Ltd.), hexyl peroxy dicarbonate (ex. Perhexyl ND, NOF Co., Ltd., dimethoxybutyl peroxy dicarbonate (ex. Peroyl MBP, NOF Co., Ltd.), bis (3-methoxy-3-methoxybutyl) peroxy dicarbonate (ex. Peroyl SOP, NOF company (product)), Dibutyl peroxy dicarbonate, dicetyl peroxy dicarbonate, dimyristyl peroxy dicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, hexyl peroxy Pivalate (ex. Perhexyl PV, NOF Co., Ltd.), butyl peroxy pivalate (ex. Perbutyl, NOF Co., Ltd.), trimethylhexanoyl peroxide (ex. Peroyl 355, NOF Co., Ltd.), Dimethyl hydroxybutyl peroxy neodecanoate (ex. Luperox 610M75, Atofina (ex)), amyl peroxy neodecanoate (ex. Luperox 546M75, Atofina (ex)), butyl peroxy neodecanoate (ex Luperox 10M75, Atofina, t-butylperoxy 2-ethylhexanoate (ex. Luperox 26), t-butylperoxy neoheptanoate, amylperoxy pivalate (ex. Luperox 546M75, Alofina), t-butylperoxy pivalate, t-amyl peroxy-2-ethylhexanoate, lauryl peroxide, dilauuroyl peroxide, didecanoyl peroxide Organic peroxides such as benzoyl peroxide or dibenzoyl peroxide, and the like, but are not limited thereto. In the present invention, one or more kinds of the above-described thermal initiators may be used.

In the adhesive composition of the present invention, the thermal initiator may be included in an amount of 0.001 part by weight to 200 parts by weight, preferably 10 parts by weight to 200 parts by weight, and more preferably 100 parts by weight to 200 parts by weight, based on 100 parts by weight of the polymer. In the present invention, by controlling the content of the thermal initiator in the above range, the adhesive can be formulated to have more excellent physical properties.

The adhesive composition of the present invention may also contain at least one additive selected from the group consisting of epoxy resins, crosslinkers, ultraviolet stabilizers, antioxidants, colorants, reinforcing agents, fillers, antifoams, surfactants, and plasticizers, in a range that does not affect the effects of the invention. It may further include a.

The adhesive composition containing each of the above components may be composed of a photocurable type and a solventless type. In this way, the adhesive composition is composed of a solvent-free type, so that the solvent volatilization step is not necessary in the process of forming the adhesive layer. Moreover, the adhesive agent of this invention can exhibit the outstanding adhesive physical property with respect to both the to-be-adhered body and the to-be-adhered body. Accordingly, the adhesive composition of the present invention is a polarizer, for example, a resin film having low water vapor permeability and showing hydrophobicity, such as polyester, polycarbonate, amorphous polyolefin, cycloolefin, or acrylic resin film. For example, it can be effectively used as an adhesive composition for polarizers which adheres to a hydrophilic adherend such as a polyvinyl alcohol (PVA) polarizer.

The present invention also provides a polarizer; And an adhesive layer formed on one or both surfaces of the polarizer and including a cured product of the adhesive composition. And it relates to a polarizing plate comprising a protective film attached to the polarizer via the adhesive layer.

The kind of polarizer contained in the polarizing plate of this invention is not specifically limited, For example, the general kind known in this field, such as a polyvinyl alcohol-type polarizer, can be employ | adopted without a restriction | limiting.

The polarizer is a functional film or sheet capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed in a polyvinyl alcohol-based resin film. Polyvinyl alcohol-type resin which comprises a polarizer can be obtained by gelatinizing polyvinylacetate-type resin, for example. In this case, the polyvinyl acetate-based resin that can be used may include not only homopolymers of vinyl acetate but also copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomer copolymerizable with vinyl acetate include monomers such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group, or a mixture of two or more thereof. no. The degree of gelation of the polyvinyl alcohol-based resin is usually 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin may be about 1,000 to 10,000, preferably about 1,500 to 5,000.

The above-mentioned polyvinyl alcohol-type resin is formed into a film, and can be used as a raw film of a polarizer. The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, The general method known in this field can be used. The thickness of the raw film formed into a polyvinyl alcohol-based resin is not particularly limited, and may be appropriately controlled within, for example, 1 µm to 150 µm. In consideration of ease of stretching and the like, the thickness of the master film can be controlled to 10 ㎛ or more.

The polarizer is a step of stretching (ex. Uniaxial stretching) the polyvinyl alcohol resin film as described above, a step of dyeing the polyvinyl alcohol resin film with a dichroic dye, adsorbing the dichroic dye, and a dichroic dye adsorbed. The polyvinyl alcohol-based resin film can be produced through a process of treating with a boric acid aqueous solution and a process of washing with water after treating with a boric acid aqueous solution. As the dichroic dye, iodine or dichroic organic dyes may be used.

In the present invention, the kind of protective film attached to one or both surfaces of the polarizer as described above by the adhesive of the present invention is not particularly limited. In addition, in this invention, when a protective film is affixed on both surfaces of a polarizer, the protective film may be the same kind or may be a different kind of film.

The kind of protective film that can be applied in the present invention is not particularly limited, and for example, a cellulose film (ex, triacetyl cellulose (TAC)), an amorphous polyolefin film, a polyester resin film, an acrylic resin film, poly Films, such as a carbonate resin film, a polysulfone resin film, an alicyclic polyimide resin film, or a cyclic olefin (COP) resin film, can be used. In the present invention, for example, when the protective film is attached to both surfaces of the polarizer, at least one film is an amorphous polyolefin film, polyester resin film, acrylic resin film, polycarbonate resin film, polysulfone resin A film, an alicyclic polyimide resin film, or a cyclic olefin (COP) resin film or the like may be configured, but is not limited thereto.

Such a film is inferior in moisture permeability compared with a cellulose film, and shows hydrophobicity unlike the polarizer which usually shows hydrophilicity, and it is very difficult to adhere to a polarizer using existing aqueous adhesives etc. However, the adhesive composition of the present invention can be composed of a photocurable solvent-free type, and can be effectively used for the attachment of a low moisture permeability film as described above, in particular between adherends exhibiting different properties such as hydrophilicity and hydrophobicity. Effective adhesive performance can be achieved.

The method of attaching the polarizer and the protective film using the adhesive composition of the present invention is not particularly limited. In the present invention, for example, the polarizer and / or protective film by dropping the adhesive composition of the present invention, and simultaneously laminated, and then irradiated with electromagnetic waves to the adhesive composition, and aged under appropriate conditions, the polarizer And a protective film is affixed and a polarizing plate can be manufactured.

The means for irradiating electromagnetic waves and the conditions for irradiating electromagnetic waves are not particularly limited. In view of the composition of the adhesive composition to be used and the like, conventional means in this field may be appropriately employed.

In addition, the polarizing plate of the present invention may further include a functional film such as a retardation plate, an optical compensation film, a reflection sheet, and a brightness enhancement film as appropriate, and the opposite side of the surface attached to the polarizer in the aforementioned protective film. The pressure-sensitive adhesive layer can be formed of a material (ex. Acrylic pressure-sensitive adhesive) suitable for the above, and the polarizing plate can be constituted by an adhesive polarizing plate.

The present invention also relates to a liquid crystal display device comprising a liquid crystal panel in which the polarizing plate according to the present invention is attached to one side or both sides.

The kind of liquid crystal panel contained in the liquid crystal display device of this invention as mentioned above is not specifically limited. In the present invention, for example, not limited to the type, F various passive matrix including TN (Twisted Neumatic) type, STN (Super Twisted Neumatic) type, F (ferroelectric) type, PD (polymer dispersed LCD) type, etc. system; Various active matrix schemes including two terminals and three terminals; Both known liquid crystal panels, including IPS mode panels and VA mode panels, can be applied. In addition, the kind and other manufacturing method of the other structure contained in the liquid crystal display device of this invention are not specifically limited, either, The general structure of this field can be employ | adopted and used without a restriction | limiting.

[Example]

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited by the following examples.

Example 1.

Preparation of Polymer (A) Including Hydrophilic Residue and Reactive Functional Group

In a one-neck round bottom flask, 29.48 g (0.258 mol) of vinyl pyrrolidone (VP), 16.31 g (0.189 mol) of vinyl acetate (VA), 10.76 glycidyl methacrylate (GMA) g (0.076 mol) and 22.0 g (0.189 mol) of hydroxyethyl acrylate (HEA) were sequentially injected (equivalent ratio: VP: VA: GMA: HEA = 7: 5: 2: 5), and ethanol was added as a solvent. The solid content was adjusted to about 30% by weight. The flask was then kept at about 70 ° C. and purged with nitrogen. After about 30 minutes, 2.07 g (0.0075 mol) of chain transfer agent (CTA) and 2.68 g (0.075 mol) of radical initiator (azobisisobutyronitrile (AIBN)) were injected and 3 hours It reacted about. The reaction was then precipitated in n-hexane and washed. The washing was repeated twice and dried at a temperature of about 70 ° C. for 24 hours to prepare a polymer (A) having a weight average molecular weight of 27,100 and a glass transition temperature of about 40 ° C. The polymer (A) thus prepared was diluted in hydroxyethyl acrylate (HEA) so as to have a solid content of about 20% by weight, and used for preparing an adhesive.

Preparation of adhesive composition

About 533 parts by weight of bisphenol A epoxy acrylate based on 100 parts by weight of the prepared polymer; 2067 parts by weight of the monomer component (about 1233 parts by weight of hydroxyethyl acrylate, about 667 parts by weight of 2- (2-ethoxyethoxy) ethyl acrylate and about 167 parts by weight of β-carboxyethyl acrylate); About 333 parts by weight of glyoxylic acid as a curing agent; About 100 parts by weight of benzoyl peroxide (BPO) as a thermal initiator and about 267 parts by weight of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as a photoinitiator were prepared to prepare a photocurable solvent-free adhesive composition. .

Preparation of Polarizer

The prepared adhesive composition was dropped on an acrylic protective film and simultaneously laminated to the acrylic protective film and the polyvinyl alcohol polarizer. Thereafter, ultraviolet rays (wavelength: about 320 to 440 nm, roughness: about 200 W / cm ² , light amount = about 450 mJ / cm ² ) were irradiated using a mercury lamp on the protective film side to cure the adhesive composition, After further aging for 2 minutes at a temperature of 90 ℃ to prepare a polarizing plate.

Example 2.

Preparation of Polymer (B) Including Hydrophilic Residue and Reactive Functional Group

29.48 g (0.258 mol) of vinyl pyrrolidone (VP), 16.31 g (0.189 mol) of vinyl acetate (VA) and 22.0 g of hydroxyethyl acrylate (HEA) in a one-neck round bottom flask (0.189 mol) was sequentially injected (equivalent ratio: VP: VA: HEA = 7: 5: 5), and ethanol was added as a solvent to adjust the solid content to about 30% by weight. The temperature of the flask was then maintained at about 64 ° C. and purged with nitrogen. After about 30 minutes, 7.61 g (0.046 mo) of a radical initiator (azobisisobutyronitrile (AIBN)) was injected and reacted for about 3 hours. The reaction was then precipitated in n-hexane and washed. The washing was repeated twice and dried at a temperature of about 70 ° C. for 24 hours to prepare a polymer having a weight average molecular weight of 77,900 and a glass transition temperature of about 40 ° C. The polymer (B) thus prepared was diluted in hydroxyethyl acrylate so that the solid content was about 20% by weight, and used for preparing the adhesive.

Preparation of Adhesive Composition and Polarizing Plate

An adhesive composition and a polarizing plate were prepared in the same manner as in Example 1, except that the polymer (B) prepared above was used.

Physical properties of the polarizing plates prepared above were measured by the following methods.

1. Evaluation of heat resistance

After cutting the polarizing plate prepared in Example to a size of 5cm × 5cm, it was left in an oven at 80 ℃ for a predetermined time, and taken out to evaluate the appearance (cracking, curling, etc.) and optical properties of the polarizing plate It measured according to the following criteria.

≪ Heat resistance evaluation standard &

○: The appearance and optical properties are good even after the polarizing plate is left for 500 hours at 80 ° C.

(Triangle | delta): Appearance and optical properties are favorable also after leaving a polarizing plate at 80 degreeC for 100 hours.

X: Appearance and / or optical property are bad after leaving a polarizing plate at 80 degreeC for 100 hours.

2. Evaluation of Water Resistance

After cutting the polarizing plate prepared in Example to a size of 4cm × 6cm, it was left in a constant temperature water bath at 60 ℃ for a predetermined time, and then observed the appearance of the polarizing plate (such as cracking or curling), and Evaluation was made according to the standard.

<Water resistance evaluation standard>

(Circle): Appearance is good even after leaving a polarizing plate at 60 degreeC for 24 hours.

(Triangle | delta): Appearance is good even after leaving a polarizing plate at 60 degreeC for 12 hours.

X: Appearance is bad after leaving a polarizing plate at 60 degreeC for 4 hours or less.

3. Peel force evaluation

The polarizing plate prepared in Example was left at room temperature for 3 days, and then, using a physical property analyzer (Texture analyzer, Stable Microsystem, UK), at a peel rate of 5 mm / sec and a peel angle of 90 °. Peeling force between the polarizer and the protective film was measured.

The measurement results are summarized in Table 1 below.

Example 1 Example 2 Heat resistance ○ ○ Water resistance ○ △ Peeling force (N / 2cm) 4 3

As can be seen from the results of Table 1 above, in the case of using the adhesive composition according to the present invention, an acrylic protective film having low water vapor permeability and showing hydrophobicity is attached to a polyvinyl alcohol polarizer (3 N / m or more). ) Showed excellent adhesion. In addition, when using the adhesive according to the present invention, it was confirmed that excellent heat resistance and water resistance to the polarizing plate can be secured.

Claims (23)

Polymers having a hydrophilic moiety and a reactive functional group; Epoxy acrylate; And a curing agent having a functional group capable of reacting with the reactive functional group of the polymer,
The hydrophilic moiety may be a 3-8 membered heterocyclic moiety comprising nitrogen and oxygen as hetero atoms; Or a 3-8 membered heterocyclic moiety substituted with an oxo group and containing nitrogen as a hetero atom. delete The polymer according to claim 1, wherein the polymer is a hydroxy group, carboxyl group, alkoxy, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkyloxycarbonyl, alkylaminoalkyloxycarbonyl, dialkylaminoalkyloxycarbon A photocurable adhesive composition further comprising at least one hydrophilic moiety selected from the group consisting of alkyl and alkylcarbonyloxy. 4. The composition of claim 3, wherein the hydrophilic moiety is aminocarbonyl; (C _1-4 ) alkylaminocarbonyl; Di (C _1-4 ) alkylaminocarbonyl; Amino (C _1-4 ) alkyloxycarbonyl; Or (C _1-4 ) alkylcarbonyloxy. The photocurable adhesive composition according to claim 1, wherein the reactive functional group is at least one selected from the group consisting of a hydroxy group, a carboxyl group, an amine group, a cyclic ether group, a (meth) acryloyl group, and a (meth) acryloyloxy group. The photocurable adhesive composition of claim 1, wherein the polymer comprises 1 to 3 moles of hydrophilic moiety per mole of reactive functional group. The photocurable adhesive composition of claim 1, wherein the polymer has a weight average molecular weight of 20,000 to 120,000. The photocurable adhesive composition of claim 1, wherein the polymer has a glass transition temperature of 10 ° C to 70 ° C. The photocurable adhesive composition according to claim 1, wherein the epoxy acrylate is an aromatic epoxy acrylate. The photocurable adhesive composition of claim 1, wherein the epoxy acrylate is included in an amount of 100 parts by weight to 1,000 parts by weight based on 100 parts by weight of the polymer. The photocurable adhesive composition of Claim 1 which is a compound containing a carboxyl group or an aldehyde. The photocurable adhesive composition according to claim 1, wherein the curing agent is at least one selected from the group consisting of an aldehyde compound, a dialdehyde compound, a monocarboxylic acid compound, a dicarboxylic acid compound, and a compound containing an aldehyde and a carboxyl group. The photocurable adhesive composition of claim 1, wherein the curing agent is included in an amount of 100 parts by weight to 500 parts by weight based on 100 parts by weight of the polymer. The photocurable adhesive composition according to claim 1, further comprising a monomer component. The photocurable adhesive composition according to claim 14, wherein the monomer component comprises at least one selected from the group consisting of a hydroxy group-containing monomer, a carboxyl group-containing monomer, an alkoxy group-containing monomer and a heterocyclic moiety-containing monomer. The photocurable adhesive composition according to claim 14, wherein the monomer component is included in an amount of 1,000 to 5,000 parts by weight based on 100 parts by weight of the polymer. The adhesive composition of claim 1 further comprising a photoinitiator. The adhesive composition according to claim 17, wherein the photoinitiator is included in an amount of 100 parts by weight to 500 parts by weight with respect to 100 parts by weight of the polymer. The photocurable adhesive composition of claim 1 further comprising a thermal initiator. The photocurable adhesive composition according to claim 19, wherein the thermal initiator is included in an amount of 0.001 part by weight to 200 parts by weight with respect to 100 parts by weight of the polymer. A polarizer; An adhesive layer formed on one side or both sides of the polarizer and including a cured product of the adhesive composition according to any one of claims 1 and 3 to 20; And a protective film attached to the polarizer through the adhesive layer. The protective film is a cellulose film, an amorphous polyolefin film, a polyester resin film, an acrylic resin film, a polycarbonate resin film, a polysulfone resin film, an alicyclic polyimide resin film or a ring. A polarizing plate which is a type olefin resin film. A liquid crystal display device comprising a liquid crystal panel in which the polarizing plate of claim 21 is attached to one side or both sides.