KR20180013429A - Adhesive composition, protective film and polarizing plate comprising adhesive layer formed by using the same and display device comprising the same - Google Patents

Abstract

The present invention relates to an adhesive composition, and a polarizing plate including an adhesive layer formed by using the same. The adhesive composition comprises a cationic polymerizable monomer and a radical polymerizable monomer, wherein the radical polymerizable monomer includes a tricyclodecane dimethanol diacrylate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an adhesive composition, a protective film and a polarizing plate including the adhesive layer formed using the adhesive composition, and an image display device including the adhesive composition.

The present specification relates to a polarizer including an adhesive composition and an adhesive layer formed using the same.

The polarizing plate has been used as a structure in which a protective film is laminated on one or both sides of a polarizer made of polyvinyl alcohol (PVA) resin dyed with a dichroic dye or iodine. Conventionally, a triacetyl cellulose (TAC) film has been mainly used as a polarizer protective film. However, such a TAC film has a problem that it is easily deformed in a high temperature and high humidity environment. Recently, protective films of various materials capable of replacing TAC films have been developed. For example, protective films such as polyethylene terephthalate (PET), cycloolefin polymer (COP) Or a mixture thereof.

At this time, as an adhesive used for attaching the polarizer and the protective film, an aqueous adhesive mainly composed of an aqueous solution of a polyvinyl alcohol resin is used. However, in the case of the water-based adhesive, when an acrylic film or a COP film other than TAC is used as a protective film, the adhesive strength is weak, so that the use thereof is limited depending on the film material. In addition, in the case of the water-based adhesive, in addition to the problem of defective adhesive force depending on the material, when the material of the protective film applied to both surfaces of the PVA element is different, a problem of curling of the polarizer due to the drying process of the water- Problems such as lowering of physical properties occur. Furthermore, in the case of using the water-based adhesive, a drying process is indispensable. In such a drying process, a difference in moisture permeability, thermal expansion, As an alternative to the above-mentioned problems, a method of using a non-aqueous adhesive instead of an aqueous adhesive has been proposed.

Until now, the non-aqueous adhesive for a polarizing plate can be divided into an adhesive and a cation-curable adhesive according to the curing method. Cation-curable adhesives have the advantage of having excellent adhesion to films of various materials, but they have many disadvantages in the manufacturing process due to the slow curing rate and low curing degree. In order to solve the problem of the cation-curable adhesive, an adhesive containing an acrylamide-based compound as a main component has been proposed. However, in the case of an adhesive containing an acrylamide-based compound as a main component, the curing speed is faster than that of the cation-curable adhesive, but the curing speed is slowed in the high-humidity atmosphere and the adhesive strength is lowered. On the other hand, in the polarizing plate manufacturing process, the water content is high because the polyvinyl alcohol film includes a wet process in which the swelling, the dyeing, the drawing, and the like are carried out in an aqueous solution. Therefore, in order to apply the acrylamide-based adhesive to the polarizing plate, Such as hot-air drying, surface treatment such as plasma, and the like.

Therefore, it is required to develop an adhesive which can be applied to a polarizing plate without any additional treatment and which does not lower the curing rate and adhesive force even in a high humidity environment.

Japanese Laid-Open Publication No. 2003-121644

The present specification provides a polarizer including an adhesive composition and an adhesive layer formed using the adhesive composition.

An adhesive composition comprising a cationic polymerizable monomer and a radically polymerizable monomer, wherein the radically polymerizable monomer provides an adhesive composition comprising tricyclocetane dimethanol diacrylate.

According to one embodiment of the present disclosure, a protective film; And a protective film provided on one side of the protective film and having an adhesive layer formed of the adhesive composition described above.

According to one embodiment of the present disclosure, there is provided a polarizer comprising: a polarizer; An adhesive layer provided on at least one surface of the polarizer and formed of the above-mentioned adhesive composition; And a protective film provided on at least one side of the adhesive layer.

Further, according to one embodiment of the present disclosure, a display panel; And the above-mentioned polarizing plate provided on one side or both sides of the display panel.

The adhesive composition according to one embodiment of the present disclosure can have a high glass transition temperature after curing, thereby making it possible to produce a thermally stable polarizing plate.

In addition, it not only has excellent adhesion to films of various materials such as TAC film, acrylic film, COP film, and PET film, but also has excellent water resistance and can stably maintain adhesion even at high humidity.

Hereinafter, the present specification will be described in detail.

In this specification, when a part is referred to as "including " an element, it is to be understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

In this specification, when a member is located on another member, it includes not only the case where the member is in contact with the other member but also the case where another member exists between the two members.

According to one embodiment of the present disclosure, there is provided an adhesive composition comprising a cationic polymerizable monomer and a radical polymerizable monomer, wherein the cationic polymerizable monomer comprises an epoxy compound and an oxetane compound, wherein the radical polymerized monomer is tricyclotetalkedimethanol di Acrylate. ≪ / RTI >

Since the adhesive composition according to one embodiment of the present disclosure includes tricyclodecane dimethanol diacrylate, it has a high glass transition temperature, has no stick and slip phenomenon, and has an adhesion of 1.5 N / 2 cm or more .

According to one embodiment of the present invention, the epoxy compound contains at least one epoxy group in the molecule.

According to one embodiment of the present invention, the epoxy compound may be an alicyclic epoxy compound, an aromatic epoxy compound, a hydrogenated epoxy compound, an epoxy group-containing (meth) acrylic compound, or an aliphatic epoxy compound. These may be used singly or in combination of two or more.

The alicyclic epoxy compound means an epoxy compound in which an epoxy group is formed between two adjacent carbon atoms constituting an aliphatic hydrocarbon ring, but is not limited thereto. For example, 2- (3,4- Epoxy) cyclohexyl-5,5-spiro- (3,4-epoxy) cyclohexane-m-dioxane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4- 6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, vinylcyclohexanedioxide, bis (3,4-epoxycyclohexylmethyl) adipate, bis (2,3-epoxycyclohexylmethyl) adipate, exo-exobis (2,3-epoxycyclopentyl) ether, endo-exobis (2,3-epoxycyclopentyl) ether, 2,2- (2,3-epoxypropoxy) cyclohexyl] propane, 2,6-bis (2,3-epoxypropoxycyclohexyl-p-dioxane), 2,6- ) Norbornene, limonene dioxide, 2,2-bis (3,4-epoxycyclohexyl) propane, dicyclopentadienedioxide, 1,2-epoxy-6- (2,3-epoxypropoxy) (2,3-epoxy) cyclopentylphenyl-2,3-epoxypropyl ether, 1- (2,3-epoxypropoxy) phenyl-5,6-epoxyhexa (2,3-epoxy) cyclopentylphenyl-2,3-epoxypropyl ether), 1,2-bis [5- (1,2-epoxy) -4, Ethane cyclopentenyl phenyl glycidyl ether, methylene bis (3,4-epoxycyclohexane) ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylene bis (3, Epoxycyclohexanecarboxylate), ε-caprolactone (1 to 10 mol) adduct of 3,4-epoxycyclohexanemethanol and poly (3 to 20) alcohol (GR, TMP, PE, DPE, Hexapentaerythritol), and the like. Among them, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is particularly preferably used from the viewpoint of reactivity.

The aromatic epoxy compound refers to an epoxy compound containing at least one aromatic hydrocarbon ring in the molecule. Examples of the epoxy compound include, but are not limited to, diglycidyl ether of bisphenol A, 4,4'-methylene Bisphenol diglycidyl ether, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; Novolak type epoxy resins such as phenol novolak epoxy resin, cresol novolac epoxy resin and hydroxybenzaldehyde phenol novolac epoxy resin; Glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and epoxy polyvinylphenols, and the like.

The hydrogenated epoxy compound refers to an epoxy compound obtained by selectively hydrogenating the aromatic epoxy compound under a pressure in the presence of a catalyst, but is not limited thereto. Of these, the hydrogenated bisphenol A It is preferable to use diglycidyl ether.

The epoxy group-containing (meth) acrylic compound means a compound containing both an epoxy group and a (meth) acryloyloxy group in the molecule, and includes, for example, glycidyl acrylate, 2-methyl Glycidyl acrylate, 3,4-epoxybutyl acrylate, 6,7-epoxyheptyl acrylate, 3,4-epoxycyclohexyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate , 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl methacrylate, 3,4-epoxycyclohexyl methacrylate, and 4-hydroxybutyl acrylate glycidyl ether.

The aliphatic epoxy compound refers to an epoxy compound containing an aliphatic chain or an aliphatic ring in the molecule and includes, for example, 1,4-cyclohexanedimethanol diglycidyl ether, 1 , 4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyldiglycidyl ether, resorcinol diglycidyl ether, diethylene glycol di glycidyl ether, ethylene glycol di Glycidyl ether, trimethylolpropane triglycidyl ether, n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and the like.

On the other hand, the epoxy compound may be used by mixing one or two or more selected from the group consisting of an alicyclic epoxy compound, an aliphatic epoxy compound, and an epoxy group-containing (meth) acrylic compound.

At this time, the alicyclic epoxy compound is an epoxy compound having at least two epoxy groups and at least two alicyclic rings in the molecule, for example, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate Rate and the like are particularly preferable.

The aliphatic epoxy compound may be one containing at least one glycidyl ether group, and examples thereof include 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol di Hexyldiol diglycidyl ether, neopentyldiglycidyl ether, resorcinol diglycidyl ether, diethylene glycol di glycidyl ether, ethylene glycol di glycidyl ether, 1,6-hexanediol diglycidyl ether, One selected from the group consisting of trimethylolpropane triglycidyl ether, n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and o-cresyl glycidyl ether. Or more can be selected.

On the other hand, it is more preferable that the aliphatic epoxy compound has a glass transition temperature of the homopolymer of about 0 캜 to 60 캜.

The epoxy group-containing (meth) acrylic compound is preferably a glycidyl (meth) acryl-based compound such as glycidyl acrylate, glycidyl methacrylate or 3,4-epoxycyclohexylmethyl acrylate, 4-epoxycyclohexylmethyl methacrylate and the like are particularly preferable. In this case, the effect of improving the water resistance of the adhesive layer of the present invention is excellent.

According to one embodiment of the present invention, it is preferable to use at least one alicyclic epoxy compound, at least one aliphatic epoxy compound, and at least one epoxy group-containing (meth) acrylic compound. Alicyclic epoxy is preferred because it has fast curing rate and high Tg, but it can not add much amount to adhesive compound because of its high viscosity. Aliphatic epoxy has low curing speed and low Tg compared with alicyclic epoxy, but used with alicyclic epoxy Thereby lowering the viscosity of the adhesive and securing the processability, and it is possible to appropriately adjust the adhesive strength, curing speed, Tg, and the like of the adhesive. Also, the epoxy group-containing (meth) acrylic compound can improve the adhesion performance by linking the cationic polymerization monomer with the radical polymerization monomer to have a high glass transition temperature and to control the curing rate.

According to one embodiment of the present invention, the oxetane compound is not particularly limited as long as it has at least one oxetanyl group in the molecule, and various oxetane compounds well known in the art can be used. For example, the oxetane compound of the present invention includes 3,3'-oxybis (methylene) bis (3-ethyloxetane), 3-ethyl- ) Methoxymethyl] oxetane, 1,4-bis [(3-ethyloxetan-3-yl) methoxymethyl] benzene, 1,4-bis [ Benzene, 1,3-bis [(3-ethyloxetan-3-yl) methoxy] benzene, 1,2-bis [ Bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, 3,3 ' Bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, 2,7-bis [ Methoxy} phenyl] methane, bis [2- (3-ethyloxetan-3-yl) methoxy} phenyl] methane, Methoxyphenyl] propane, 2,2-bis [4 - {(3-ethyloxetan-3-yl) methoxy} phenyl] propane, 3-chloromethyl-3-ethyloxetane of novolac phenol- (3-ethyloxetan-3-yl) methoxymethyl] -tricyclo [5.2.1.0 2,6] decane, 2,3-bis [ (3-ethyloxetan-3-yl) methoxymethyl] propane, 1-butoxy-2 Methoxyethylbutane, 1,2-bis [{2- (3-ethyloxetan-3-yl) methoxy} ethylthio] ethane, Bis [(4- (3-ethyloxetan-3-yl) methylthio} phenyl] sulfide, 1,6-bis [ , 3,4,4,5,5-octafluorohexane, and the like.

When two oxetanyl groups are used as an oxetane compound, it is effective to increase the glass transition temperature of the adhesive layer, and it is advantageous in the case of having one oxetanyl group.

According to one embodiment of the present invention, the adhesive composition comprises 40 to 90 parts by weight of the cationic polymerization monomer and 10 to 60 parts by weight of the tricyclodecane dimethanol diacrylate per 100 parts by weight of the total adhesive composition, The monomer comprises 60 to 85 parts by weight and tricyclodecane dimethanol diacrylate 15 to 40 parts by weight, more preferably 65 to 75 parts by weight of cationic polymerization monomer and 25 to 35 parts by weight of tricyclodecane dimethanol diacrylate . When the above range is satisfied, the adhesive force of the adhesive is excellent.

According to one embodiment of the present invention, the cationic polymerizable monomer simultaneously uses an epoxy compound and an oxetane compound. When the epoxy compound and the oxetane compound are used at the same time, the curing rate of the epoxy group having a low photocationic curing rate can be increased by using an oxetane compound, and a high viscosity can be obtained by using oxetane as a reactive diluent Thereby ensuring the fairness of the adhesive.

According to one embodiment of the present invention, the epoxy compound is 30 to 80 parts by weight, the oxetane compound is 10 to 50 parts by weight based on 100 parts by weight of the total adhesive composition, and the tricyclotetanedimethanol diacrylate And a rate of 10 to 60 parts by weight.

When the epoxy compound satisfies the above range, the adhesiveness of the adhesive composition and the water resistance are improved. When the oxetane compound satisfies the above range, the curing rate of the adhesive composition can be increased, In addition, the use of oxetane as a reactive diluent can ensure the fairness of an adhesive having a high viscosity.

In addition, when the tricyclodecane dimethanol diacrylate satisfies the above range, the adhesive composition has an excellent effect of enhancing the physical properties of the adhesive composition, and since the curing speed is relatively faster than that of the cationic polymerization monomer, The tricyclodecane dimethanol diacrylate is preferably contained in an amount of 10 to 60 parts by weight, more preferably 15 to 40 parts by weight, based on 100 parts by weight of the total adhesive composition.

According to one embodiment of the present invention, since the glass transition temperature of the adhesive composition is 70 ° C or higher, preferably 80 ° C or higher, and the glass transition temperature is higher as the glass transition temperature is thermally stable, the upper limit is not particularly limited, Preferably not higher than 200 캜.

In the present specification, the glass transition temperature is measured by using a differential scanning calorimeter (DSC, Mettler), about 10 mg of sample is poured into a special pen, heated at a constant temperature, And a value obtained by measuring the amount of heat generated according to the temperature and measuring the glass transition temperature.

The cationic initiator is a compound which generates an acid (H +) by an active energy ray, and a cationic initiator usable in the present invention includes, for example, a sulfonium salt or an iodonium salt desirable. Specific examples of the photoacid generator containing a sulfonium salt or an iodonium salt include diphenyl (4-phenylthio) phenylsulfonium hexafluoroantimonate (Diphenyl (4- phenylthio) phenylsulfonium hexafluoroantimonate), diphenyl (4-phenylthio) phenylsulfonium hexafluorophosphate, phenyl (4- (2-methylpropyl) phenyl] -iodonium hexa (2-methylpropyl) phenyl] -iodonium hexafluorophosphate, (thiodi-4,1-phenylene) bis (diphenylsulfonium) dihexafluoroantimonate ((Thiodi- 4,1-phenylene) bis (diphenylsulfonium) dihexafluoroantimonate and thiodi-4,1-phenylene bis (diphenylsulfonium) bis (diphenylsulfonium) dihexafluoroantimonate) dihexafluorophosphate), but is limited to at least one selected from the group consisting of is.

The radical initiator is used for accelerating the curing rate by promoting the radical polymerization property. As the radical initiator, radical initiators generally used in the art can be used without limitation.

Examples of the photosensitizer include, but are not limited to, carbonyl compounds, organic sulfur compounds, persulfates, redox compounds, azo and diazo compounds, anthracene compounds, halogen compounds, and photoreactive pigments .

In addition, the adhesive composition for a polarizing plate of the present invention may further include a silane coupling agent, if necessary, together with the above components. When the silane coupling agent is included, the silane coupling agent lowers the surface energy of the adhesive, thereby improving wetting of the adhesive.

In this case, the silane coupling agent preferably contains a cationic polymerizable functional group such as an epoxy group, a vinyl group, and a radical group. When a silane coupling agent not containing a cationic polymerizable functional group is used, the wettability can be improved without lowering the glass transition temperature as compared with a silane coupling agent containing no surfactant or cationic polymerizable functional group . This is because the cationic polymerization functional group of the silane coupling agent reacts with the silane group of the adhesive composition to form a crosslinked structure, thereby reducing the lowering of the glass transition temperature of the adhesive layer after curing.

The silane coupling agent usable in the present invention may be a silane coupling agent represented by the following general formula (1), but is not limited thereto.

[Chemical Formula 1]

Si (R1) n (R2) _{4- n}

R 1 is a functional group having a cyclic ether group or a vinyloxy group bonded to a silicon atom and R 2 is a hydrogen, a hydroxyl group, an alkyl group or an alkoxy group bonded to a silicon atom , and n is an integer of 1 to 4.

According to one embodiment of the present invention, the adhesive force of the adhesive composition is 1.5 N / 2 cm or more, preferably 2.0 N / 2 cm or more and 20 N / 2 cm or less.

In this specification, the adhesive force is a value measured through peeling test of the polarizing plate. Specifically, in the peeling test, the prepared polarizing plate was cut to a width of 20 mm and a length of 100 mm, and the peeling force of the polarizer and the polymer film was measured at a speed of 300 m / min and 90 degrees with a Texture Analyzer (Stable Micro Systems TA-XT Plus) Lt; / RTI >

According to one embodiment of the present disclosure, a protective film; And a protective film provided on one side of the protective film and having an adhesive layer formed of the adhesive composition described above.

According to one embodiment of the present invention, the protective film is an acrylic film.

According to one embodiment of the present invention, the adhesive force of the adhesive layer is 1 N / 2 cm or more, preferably 1.5 N / 2 cm or more and 20 N / 2 cm or less, more preferably 2.0 N / 2 cm or less.

According to one embodiment of the present invention, the adhesive force of the adhesive layer is 1.5 N / 2 cm or more, preferably 2.0 N / 2 cm or more and 20 N / 2 cm or less with respect to the TAC film.

According to one embodiment of the present disclosure, there is provided a polarizer comprising: a polarizer; An adhesive layer provided on at least one surface of the polarizer and formed of the above-mentioned adhesive composition; And a protective film provided on at least one side of the adhesive layer.

The polarizer is not particularly limited and a film made of polyvinyl alcohol (PVA) containing a polarizer well known in the art, for example, iodine or a dichroic dye, can be used. The polarizer may be prepared by saponifying iodine or a dichroic dye to a PVA film, but the production method thereof is not particularly limited. In the present specification, the polarizer means a state not including a protective film, and the polarizer means a state including a polarizer and a protective film.

Next, the adhesive layer is formed using an adhesive composition according to the above-described embodiments of the present invention, and may be formed by a method well known in the art. For example, the adhesive composition may be applied to one side of the polarizer or the protective film to form an adhesive layer, and then the polarizer and the protective film are laminated and cured. At this time, the application may be performed by coating methods well known in the art, for example, spin coating, bar coating, roll coating, gravure coating, blade coating and the like.

On the other hand, the curing can be performed by irradiating an active energy ray such as an ultraviolet ray, a visible ray, an electron ray, or the like. For example, a method of irradiating ultraviolet light of about 10 to 2500 mJ / cm ² using a metal halide lamp.

Alternatively, the curing may be performed by thermal curing, more specifically, by thermal curing at a curing temperature of 80 캜 or higher. At this time, if necessary, a known amine-based initiator may be further added to the composition in order to accelerate the curing rate upon thermal curing.

Alternatively, the curing may be to further perform thermosetting after the photo-curing, or may be to further perform photo-curing after thermosetting.

On the other hand, the thickness of the adhesive layer is preferably in the range of more than 0 to 20 μm or less, more preferably 0 to 10 μm or less, preferably 0.1 to 10 μm or 0.1 to 5 μm or so. If the thickness of the adhesive layer is too thin, the uniformity and adhesion of the adhesive layer may be lowered. If the thickness of the adhesive layer is too thick, the appearance of the polarizing plate may be wrinkled.

The protective film is used for supporting and protecting the polarizer. Various protective films of various materials such as a cellulose film, a polyethylene terephthalate (PET) film, a cycloolefin polymer (COP, cycloolefin polymer) film, an acrylic film, and the like. Of these, it is particularly preferable to use an acrylic film in consideration of optical characteristics, durability, economical efficiency and the like.

On the other hand, the acrylic film usable in the present invention can be obtained by molding a molding material containing a (meth) acrylate resin as a main component by extrusion molding. In this case, the (meth) acrylate-based resin contains a resin containing a (meth) acrylate-based unit as a main component, and includes not only a homopolymer resin composed of a (meth) acrylate- But also a copolymer resin in which other monomer units are copolymerized and a blend resin in which another resin is blended with the above (meth) acrylate resin.

On the other hand, the (meth) acrylate-based unit may be, for example, an alkyl (meth) acrylate-based unit. Here, the alkyl (meth) acrylate-based unit means both an alkyl acrylate-based unit and an alkyl methacrylate-based unit, and the alkyl (meth) acrylate-based alkyl group preferably has 1 to 10 carbon atoms , More preferably from 1 to 4 carbon atoms.

Examples of the monomer unit copolymerizable with the (meth) acrylate-based unit include a styrene-based unit, a maleic anhydride-based unit, and a maleimide-based unit. Examples of the styrene-based unit include, but are not limited to, styrene,? -Methylstyrene, and the like; Examples of the maleic anhydride monomer include, but are not limited to, maleic anhydride, methylmaleic anhydride, cyclohexylmaleic anhydride, phenylmaleic anhydride and the like; Examples of the maleimide-based monomer include, but are not limited to, maleimide, N-methylmaleimide, N-cyclohexylmaleimide, and N-phenylmaleimide. These may be used alone or in combination.

On the other hand, the acrylic film may be a film containing a (meth) acrylate resin having a lactone ring structure. Specific examples of the (meth) acrylate resin having a lactone ring structure include, for example, lactones described in Japanese Unexamined Patent Application Publication No. 2000-230016, Japanese Unexamined Patent Application Publication No. 2001-151814, Japanese Unexamined Patent Application Publication No. 2002-120326, (Meth) acrylate-based resin having a cyclic structure.

The method for producing the acrylic film is not particularly limited and, for example, a (meth) acrylate resin and other polymers and additives may be thoroughly mixed by any suitable mixing method to prepare a thermoplastic resin composition, Or a (meth) acrylate resin, other polymers, additives and the like may be prepared as separate solutions and then mixed to form a homogeneous mixture solution, and then the mixture may be formed into a film. The acrylic film may be either an unstretched film or a stretched film. In the case of a stretched film, it may be a uniaxially stretched film or a biaxially stretched film, and in the case of a biaxially stretched film, it may be a simultaneous biaxially stretched film or a sequential biaxially stretched film.

Meanwhile, the polarizing plate of the present invention may further include a primer layer between the adhesive layer and the protective film to further improve the adhesive force. At this time, the primer layer may be formed by applying a coating liquid containing a water-dispersible polymer resin, water-dispersible fine particles and water on a protective film by using a bar coating method, a gravure coating method, and drying. The water-dispersible polymer resin may be, for example, water-dispersed polyurethane resin, water-dispersed acrylic resin, water-dispersed polyester resin, or a combination thereof, and the water-dispersible fine particles may be inorganic fine particles such as silica, titania, alumina, zirconia Organic fine particles made of a silicone resin, a fluorine resin, a (meth) acrylic resin, a crosslinked polyvinyl alcohol and a melamine resin, or a combination thereof may be used, but the present invention is not limited thereto.

According to one embodiment of the present invention, the glass transition temperature of the adhesive layer is 70 DEG C or higher, preferably 80 DEG C or higher, and the upper limit is not particularly limited, but is preferably 200 DEG C or lower.

In the present specification, the glass transition temperature is measured by using a differential scanning calorimeter (DSC, Mettler), about 10 mg of sample is poured into a special pen, heated at a constant temperature, And a value obtained by measuring the amount of heat generated according to the temperature and measuring the glass transition temperature.

≪ Glass Transition Temperature (Tg) Measurement Method >

The glass transition temperature of the adhesive layer was confirmed using a differential scanning calorimeter (DSC, Mettler). After separating the adhesive layer of the polarizing plate produced under the above curing conditions, the glass transition temperature in the second run was measured by raising the temperature by -30 to 200 ° C.

According to one embodiment of the present invention, when the glass transition temperature of the adhesive layer is 70 ° C or higher, excellent effects are exhibited in the appearance characteristics, adhesion, crack occurrence, optical characteristics and the like of the polarizing plate in the evaluation of durability such as evaluation of thermal shock properties.

According to an embodiment of the present disclosure, a display panel; And a polarizing plate provided on one or both surfaces of the display panel according to the above-described embodiment.

The display panel may be a liquid crystal panel, a plasma panel, and an organic luminescent panel.

Accordingly, the image display apparatus may be a liquid crystal display (LCD), a plasma display (PDP), and an organic light emitting display (OLED).

More specifically, the image display device has a liquid crystal panel and a liquid crystal panel

And at least one of the polarizers may be a polarizer including a polarizer according to one embodiment of the present invention described above. That is, the polarizing plate comprises a polyvinyl alcohol polarizer in which iodine and / or a dichroic dye is dyed and a protective film provided on at least one surface of the polyvinyl alcohol polarizer, And a polarization degree of 10% or less and a sagging of 10 占 퐉 or less. The optical information recording medium according to claim 1,

At this time, the type of the liquid crystal panel included in the liquid crystal display device is not particularly limited. A passive matrix type panel such as a twisted nematic (TN) type, a super twisted nematic (STN) type, a ferroelectic (F) type or a polymer dispersed (PD) type; An active matrix type panel such as a two terminal or a three terminal; A known panel such as an in-plane switching (IPS) panel and a vertical alignment (VA) panel may be used. Further, the other constituent elements constituting the liquid crystal display device, for example, the types of the upper and lower substrates (for example, a color filter substrate or an array substrate) are not particularly limited and the structures known in this field are not limited Can be employed.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention.

Example  One

55/3 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 55 parts by weight of 1,6-hexane diol diglycidyl ester, 3,3'-oxybis (methylene) 55/3 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), tricyclodecane dimethanol di 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf) and 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec) were added to 100 parts by weight of the composition prepared by adding 35 parts by weight of acrylate To prepare an adhesive composition.

Comparative Example 1

55/3 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 55 parts by weight of 1,6-hexane diol diglycidyl ester, 3,3'-oxybis (methylene) 55/3 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), 1,6- 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf), 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec Co., Ltd.) ) Was added to prepare an adhesive composition.

Comparative Example  2

55/3 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 55 parts by weight of 1,6-hexane diol diglycidyl ester, 3,3'-oxybis (methylene) 55/3 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA) , 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf), and 10 parts by weight of Irgacure 250 were mixed with 100 parts by weight of a composition prepared by adding 35 parts by weight of glycol diacrylate (hydroxyl pivalic acid neopentyl glycol diacrylate (HPNDA) 1 part by weight of isopropylthioxanthone (ITX) (manufactured by SK cytec) was added to prepare an adhesive composition.

Comparative Example  3

55/3 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 55 parts by weight of 1,6-hexane diol diglycidyl ester, 3,3'-oxybis (methylene) 55/3 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), 10 parts by weight of tripropylene glycol diacrylate , 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf), 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec) Were added to prepare an adhesive composition.

Comparative Example  4

55/3 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 55 parts by weight of 1,6-hexane diol diglycidyl ester, 3,3'-oxybis (methylene) 55/3 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), 10 parts by weight of dipropylene glycol diacrylate , 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf), 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec Co., Ltd.) Were added to prepare an adhesive composition.

Evaluation of glass transition temperature

The glass transition temperature of the adhesive composition prepared in Example 1 and Comparative Examples 1 to 4 was measured, and the measurement method was as described above. The results are shown in Table 1 below.

Glass transition temperature (Tg) (占 폚) Example 1 94 Comparative Example 1 60 Comparative Example 2 85 Comparative Example 3 59 Comparative Example 4 83

Adhesion evaluation

The adhesive strength of the adhesive composition prepared in Example 1 and Comparative Examples 1 to 4 was measured with respect to the acrylic film and TAC, and the measuring method was as described above. The results are shown in Table 2 below.

Adhesion (N / 2cm) Acrylic film TAC Example 1 2.1 2.3 Comparative Example 1 2.0 1.4 Comparative Example 2 1.8 1.0 Comparative Example 3 1.8 0.7 Comparative Example 4 1.9 1.1

In Tables 1 and 2, Example 1, which is a composition comprising tricyclodecane dimethanol diacrylate according to one embodiment of the present invention, is a composition containing tricyclodecane dimethanol diacrylate and Comparative Examples 1 to 4 It was confirmed that the glass transition temperature and adhesive force were higher than those of the adhesive composition of the present invention.

Example  2

40 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 40 parts by weight of 1,6-hexanediol diglycidyl ester, 3,3'-oxybis (methylene) 40/3 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), 10 parts by weight of tricyclodecane dimethanol di 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf) and 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec) were added to 100 parts by weight of the composition prepared by adding 50 parts by weight of acrylate To prepare an adhesive composition.

Example  3

50 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 50 parts by weight of 1,6-hexanediol diglycidyl ester, 3,3'-oxybis (methylene) 50 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), 10 parts by weight of tricyclodecane dimethanol di 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf) and 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec) were added to 100 parts by weight of the composition prepared by adding 40 parts by weight of acrylate To prepare an adhesive composition.

Example  4

20 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 20 parts by weight of 1,6-hexane diol diglycidyl ester, 20 parts by weight of 3,3'-oxybis (methylene) bis (3- 10 parts by weight of glycidylmethyl acrylate (GMA), and 30 parts by weight of tricyclodecane dimethanol diacrylate were added to a solution of 20 parts by weight of 3,3'-oxybis (methylene) bis (3-ethyloxetane) 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf) and 1 part by weight of isopropylthioxanthone (ITX) (manufactured by SK cytec) were added to 100 parts by weight of the prepared composition to prepare an adhesive composition Respectively.

Example  5

, 80/3 parts by weight of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 80/3 parts by weight of 1,6-hexanediol diglycidyl ester, 3,3'-oxybis (methylene) , 80 parts by weight of bis (3-ethyloxetane) (3,3'-oxybis (methylene) bis (3-ethyloxetane)), 10 parts by weight of glycidylmethyl acrylate (GMA), 10 parts by weight of tricyclodecane dimethanol di 2 parts by weight of Irgacure 250 (manufactured by Basf), 1 part by weight of Irgacure 819 (manufactured by Basf) and 1 part by weight of Isopropylthioxanthone (ITX) (manufactured by SK cytec) were added to 100 parts by weight of the composition prepared by adding 10 parts by weight of acrylate To prepare an adhesive composition.

The adhesive compositions prepared in Examples 1 to 5 were measured for adhesion to an acrylic film and a TAC film by the above-mentioned method, and the results are shown in Table 3 below.

Epoxy Oxetane GMA
(Parts by weight) TCDDA
(Parts by weight) Initiator Adhesion [N / 2cm] CEL2021P
(Parts by weight) NPDGE
(Parts by weight) OXT221
(Parts by weight)  I250 I819 ITX Acrylic film TAC Example 2 40/3 40/3 40/3 10 50 2pt 1pt 1pt 1.4 0.8 Example 3 50/3 50/3 50/3 10 40 1.7 2.1 Example 1 55/3 55/3 55/3 10 35 1.9 2.6 Example 4 20 20 20 10 30 2.0 2.6 Example 5 80/3 80/3 80/3 10 10 1.0 2.6

Claims (15)

An adhesive composition comprising a cationic polymerizable monomer and a radical polymerizable monomer,
Wherein the radical polymerized monomer comprises tricyclocetane dimethanol diacrylate. The adhesive composition according to claim 1, wherein the cationic polymerizable monomer comprises an epoxy compound and an oxetane compound. The adhesive composition according to claim 2, wherein the epoxy compound is a mixture of one or more selected from the group consisting of an alicyclic epoxy compound, an aliphatic epoxy compound, and an epoxy group-containing (meth) acrylic compound. The adhesive composition of claim 1, wherein the adhesive composition further comprises an initiator. The adhesive composition according to claim 1, wherein, based on 100 parts by weight of the total adhesive composition,
40 to 90 parts by weight of the cationic polymerization monomer,
And 10 to 60 parts by weight of the tricyclodecane dimethanol diacrylate. The adhesive composition according to claim 1, wherein, based on 100 parts by weight of the total adhesive composition,
60 to 85 parts by weight of the cationic polymerization monomer,
And 15 to 40 parts by weight of the tricyclodecane dimethanol diacrylate. The adhesive composition according to claim 2, wherein, based on 100 parts by weight of the total adhesive composition,
30 to 80 parts by weight of the epoxy compound,
10 to 50 parts by weight of the oxetane compound, and
And 10 to 60 parts by weight of the tricyclocetane dimethanol diacrylate. The adhesive composition according to claim 1, wherein the adhesive composition has a glass transition temperature (Tg) of 70 ° C or higher. The adhesive composition according to claim 1, wherein the adhesive composition has an adhesive strength of 1.5 N / 2 cm or more. Protective film; And an adhesive layer provided on one side of the protective film and formed of the adhesive composition according to any one of claims 1 to 9. The protective film according to claim 10, wherein the adhesive layer has an adhesive strength of 1.5 N / 2 cm or more with respect to the protective film. A polarizer;
An adhesive layer provided on at least one surface of the polarizer and formed of the adhesive composition according to any one of claims 1 to 9; And
And a protective film provided on at least one surface of the adhesive layer. The polarizer according to claim 12, wherein the adhesive layer has a glass transition temperature of 80 ° C or higher. The polarizer according to claim 12, wherein the thickness of the adhesive layer is 0 to 20 탆. Display panel; And
And the polarizing plate according to claim 12 provided on one or both surfaces of the display panel.