KR20150087752A - Adhesive composition for polarizing plate, adhesive film prepared using the same, polarizing plate comprising the same and optical display apparatus comprising the same - Google Patents

Abstract

The present invention relates to an adhesive agent for a polarizing plate, an adhesive film for the polarizing plate prepared by using the same, the polarizing plate including the same, and an optical display device thereof. The adhesive agent includes: (A) an epoxy compound; (B) (meth-) acrylate compound; (C) a fluorene compound including one or both of an epoxy group and (meth-) acrylate group; and (D) a cationic polymerization initiator.

Description

TECHNICAL FIELD [0001] The present invention relates to an adhesive composition for a polarizing plate, an adhesive film for a polarizing plate produced therefrom, a polarizing plate including the same, and an optical display device including the same. BACKGROUND OF THE INVENTION SAME}

The present invention relates to an adhesive composition for a polarizing plate, an adhesive film for a polarizing plate produced therefrom, a polarizing plate including the same, and an optical display device including the same.

A method of attaching a polarizer and a cellulose-based protective film with an adhesive for a water-based polarizing plate is generally used. In recent years, by using an adhesive for a photocurable polarizing plate, it has become possible to attach various hydrophobic films such as polyethylene terephthalate (PET), cyclic olefin polymer (COP) and acrylic, as well as a cellulose-based protective film. With the introduction of the photocurable adhesive, the polarizing plate can be exposed to a thermal shock at which the low temperature and the high temperature are rapidly changed, and thus the polarizer is liable to be cracked. Accordingly, there is a need for an adhesive for a polarizing plate that has good adhesion between the polarizer and the protective film, and protects the polarizer from external thermal shock to prevent cracking of the polarizer.

In this regard, Korean Patent Laid-Open Publication No. 2008-0093361 discloses a method for solving the thermal shock problem using an acrylate containing an N-substituted amide monomer.

An object of the present invention is to provide an adhesive composition for a polarizing plate having high adhesion to a hydrophobic protective film and a polarizer.

Another object of the present invention is to provide an adhesive composition for a polarizing plate capable of preventing cracking of a polarizer against thermal shock including cycle repetition at low temperature and high temperature.

The adhesive composition for a polarizing plate according to the present invention comprises a fluorene compound containing at least one of (A) an epoxy compound, (B) (meth) acrylate compound, (C) epoxy compound, (meth) ) ≪ / RTI > cationic polymerization initiator.

The adhesive film for a polarizing plate of the present invention may be formed from the above adhesive composition.

The polarizing plate of the present invention may comprise an adhesive film for the polarizing plate.

The optical display device of the present invention may include the polarizing plate.

The present invention provides an adhesive composition for a polarizing plate having high adhesion to a hydrophobic protective film and a polarizer.

The present invention provides an adhesive composition for a polarizing plate capable of realizing an adhesive film for a polarizing plate that suppresses generation and growth of cracks in a polarizer under a thermal shock including repeated cycle at a low temperature and a high temperature.

1 is a sectional view of a polarizing plate of one embodiment of the present invention.
2 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification. In the present specification, '(meth) acrylate' means acrylate and (meth) acrylate, and 'upper' and 'lower' are defined with reference to the drawings, Lower 'to' upper '.

Hereinafter, the adhesive composition for a polarizing plate of one embodiment of the present invention will be described.

The adhesive composition for a polarizing plate of one embodiment of the present invention can be used to adhere an optical film to one or both sides of a polarizer, and the optical film can be a protective film (e.g., a non-phase difference film) or a retardation film. Specifically, the optical film may be a hydrophobic protective film having an unfavorable adhesive property in the unmodified state. Examples of the protective film include PET (polyethylene terephthalate), COP (cycloolefin polymer), acrylic film and triacetyl cellulose (TAC) film, and the like.

The adhesive composition for a polarizing plate of one embodiment of the present invention is an adhesive composition for a polarizing plate which comprises a fluorene compound containing at least one of (A) an epoxy compound, (B) a (meth) acrylate compound, (C) , And (D) a photocationic polymerization initiator. As a result, the curing reaction between the epoxy compound, the epoxy group of the (meth) acrylate compound and the fluorene compound or the (meth) acrylate group proceeds and the rigid structure of the fluorene results in the adhesive composition for the polarizing plate It is possible to give a good adhesive force between the polarizer and the optical film due to the high internal cohesive force and to suppress the occurrence and growth of cracks in the polarizer at the time of thermal shock to the maximum.

(C) A fluorene compound containing at least one of an epoxy group and a (meth) acrylate group can increase the adhesive force between the polarizer and the optical film and can prevent cracking of the polarizer upon thermal shock due to a rigid structure. An epoxy group and / or at least one (meth) acrylate group is bonded, and may be represented, for example, by the following formula (1).

≪ Formula 1 >

(Wherein R ¹ is hydrogen, a hydroxyl group, a phenyl group, an amino group, a tolyl group, a carboxylic acid group, or an alkyl group having 1 to 10 carbon atoms,

R ² is * -O- (C = O) -C (A) = CH 2, * - (B) -O- (C = O) -C (A) = CH 2, * -O- (B) (A) = CH ₂ , (2), (3), (4), (5), (6)

(2)

(3)

≪ Formula 4 >

≪ Formula 5 >

(6)

≪ Formula 7 >

(Wherein * is a connection portion of the element, A is hydrogen or a methyl group, B is an alkylene group having 1 to 20, R ⁷ is hydrogen or a methyl group, p is an integer of 1 to 10)

R ³ , R ⁴ , R ⁵ and R ⁶ are each independently hydrogen, cyano, an alkyl group having 1 to 10 carbon atoms or halogen,

m is an integer of 0 to 4, n is an integer of 1 to 5, and m + n is 5).

For example, B may be an alkylene group having 1 to 10 carbon atoms, for example, an alkylene group having 1 to 5 carbon atoms. For example, m may be 0, 1, 2, 3, 4, and n may be 1, 2, 3, 4,

For example, a fluorene compound containing at least one of an epoxy group and a (meth) acrylate group is derived from bisphenoxyethanolfluorene (BPEF), and a hydroxyl group attached to the reactor is reacted with an epoxy group, a (meth) Acrylate group, which may be commercially available and used.

The fluorene compound containing an epoxy group has an epoxy equivalent weight in comparison with the following epoxy compounds, so that it can prevent an increase in the total viscosity within a proper content range and react appropriately with other epoxy compounds. Specifically, the fluorene compound having an epoxy equivalent of 250 - 450 g / eq. In addition, the fluorene compound containing an epoxy group is less contained in comparison with the epoxy compound, so that the effect of curing the epoxy group, the increase of the viscosity of the adhesive composition due to the excessive use of the fluorene compound containing an epoxy group is prevented, It is also possible to prevent a polarizer crack caused by the polarizer. Specifically, the weight ratio of the epoxy compound to the fluorene compound containing an epoxy group in the adhesive composition for a polarizing plate (fluorene compound containing an epoxy compound / epoxy group) is more than 1, specifically 4 to 15, specifically 5 To 15% by weight.

(Meth) acrylate group is less than the following (meth) acrylate-based compound, the effect of curing of the (meth) acrylate group, the effect of excessive use of the fluorene compound containing the (meth) acrylate group It is possible to prevent the viscosity of the adhesive composition from rising, to secure the adhesive force, and to prevent the polarizer from cracking due to thermal shock. Specifically, the weight ratio of the (meth) acrylate compound to the fluorene compound containing the (meth) acrylate group in the adhesive composition for a polarizing plate (the weight ratio of the fluorene compound containing the (meth) acrylate compound / (meth) ) May be included in a weight ratio of more than 1, specifically 4 to 15, specifically 4 to 9.

A fluorene compound containing at least one of an epoxy group and a (meth) acrylate group may be contained in an amount of 1 to 25 parts by weight based on 100 parts by weight of the sum of (A), (B) and (C) The effect of preventing cracking of the polarizer is high, the adhesive strength is good, the viscosity of the adhesive composition is not excessively increased, and the coating property and the coating property can be good. Specifically, it may be contained in an amount of 3 to 15 parts by weight, for example, 5, 6, 7, 8, 9 or 10 parts by weight.

(A) The epoxy compound imparts an adhesive force between the polarizer and the optical film, and can provide high reliability due to the structural strength of the epoxy itself. In addition, cohesive force can be imparted to the adhesive film by twisting of the physical (molecular) chain of the (meth) acrylate compound and chain transfer bonding with the hydrophilic group. In addition, the epoxy compound has a high glass transition temperature to support the structure of the adhesive film to impart durability, and it is possible to impart the interfacial adhesion between the polarizer and the optical film due to the chemical bond and good wettability caused by the hydroxyl group generated during the reaction . Specifically, the epoxy compound has a glass transition temperature of 50 to 250 ° C, Specifically, it may be from 100 to 200 ° C, and in this range, it is possible to increase the durability and impart the interfacial adhesion between the polarizer and the optical film.

The epoxy-based compound can be a non-fluorene-based epoxy compound that does not contain a fluorene moiety and can be a cation-curable epoxy system in which polymerization proceeds by cations generated by a photocationic polymerization initiator. As a result, Even if the adhesive composition of the present invention is used in an excess amount, the viscosity is not increased to the extent that it affects the coating property, and sufficient adhesion force can be realized after curing. The epoxy-based compound may have an epoxy equivalent of 100 to 200 g / eq, and an appropriate adhesive curing reaction may be expected in the above-mentioned range during UV irradiation.

Specifically, the epoxy compound may include an alicyclic epoxy compound, an aromatic epoxy compound, an aliphatic epoxy compound, a hydrogenated epoxy compound, or a mixture thereof. Particularly, by using at least one of an alicyclic epoxy resin and an aromatic epoxy resin, the adhesive force of the adhesive film and the cracking of the polarizer under a thermal shock can be suppressed by imparting an internal bonding force of the adhesive after curing.

The alicyclic epoxy compound may be a compound having at least one epoxy group in the alicyclic ring. The alicyclic epoxy-based compound may be an alicyclic diepoxycarboxylate. In particular embodiments, there may be mentioned 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro- (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexyl) adipate, 3,4-epoxy-6-methylcyclohexyl- 3 ', 4'-epoxy-6'-methylcyclohexanecarboxylate, ε-caprolactone modified 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexanecarboxylate, trimethylcaprolactone denatured 3 , 4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, β-methyl-δ-valerolactone-modified 3,4-epoxycyclohexylmethyl-3'4, (3,4-epoxycyclohexanecarboxylate), ethylenebis (3,4-epoxycyclohexanecarboxylate), epoxycyclohexanecarboxylic acid esters such as ethylenebis Dioctyl phthalate, and the like epoxy hexahydrophthalic acid di-2-ethylhexyl cyclohexane.

The aromatic epoxy compounds include bisphenol A, F, and phenol novolak, cresol novolac, bisphenol A-novolak, dichloropentadiene novolac, glycidyl ether of triphenolmethane, triglycidylparaaminophenol, tetraglycidylmethylene di Aniline, and the like.

Examples of the aliphatic epoxy compound include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol Diglycidyl ether, glycerin triglycidyl ether, polypropylene glycol diglycidyl ether; Polyglycidyl ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin; Diglycidyl esters of aliphatic long chain dibasic acids; Monoglycidyl ethers of aliphatic higher alcohols; Glycidyl ethers of higher fatty acids; Epoxidized soybean oil; Butyl stearate; Octyl stearate; Epoxidized linseed oil; Epoxylated polybutadiene, and the like.

The hydrogenated epoxy compound means a resin obtained by selectively hydrogenating an aromatic epoxy resin under a pressure in the presence of a catalyst. Examples of the aromatic epoxy resin include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S; Novolak type epoxy resins such as phenol novolak epoxy resin, cresol novolak epoxy resin, and hydroxybenzaldehyde phenol novolak epoxy resin; Glycidyl ethers of tetrahydroxyphenylmethane, glycidyl ethers of tetrahydroxybenzophenone, and epoxy polyvinylphenols, and the like. Although the hydrogenated epoxy resin of the aromatic epoxy resin becomes a hydrogenated epoxy resin, it is preferable to use hydrogenated bisphenol A glycidyl ether.

The epoxy compound may be contained in an amount of 40 to 85 parts by weight based on 100 parts by weight of the total of (A), (B) and (C). In the above range, it is possible to prevent the polarizer from sticking to the optical film, to prevent the polarizer from being wetted due to an excessive increase in the viscosity of the adhesive composition, to prevent the adhesive layer from being broken due to excessive modulus rise, The crack resistance and the cuttability can be improved. Specifically 50 to 75 parts by weight, such as 50, 55, 60, 65, 70, or 75 parts by weight, of 100 parts by weight of the total of (A), (B) and (C)

The (B) (meth) acrylate compound can be polymerized by a radical initiated by light energy. In addition, the polarizer can have high reactivity without being inhibited by the moisture of the polarizer, and can exhibit adhesion to each interface of the polarizer or optical film and chain transfer bonding with the activated epoxy compound during the curing process.

The (meth) acrylate compound is a non-fluorene-based (meth) acrylate compound having no fluorene moiety, and even when used in an excessive amount in the adhesive composition of the present invention, the viscosity is not increased to such an extent as to affect coating properties Sufficient adhesion can be achieved after curing.

(Meth) acrylate-based compound does not necessarily have a hydroxyl group, but it is preferable that the (meth) acrylate-based compound has at least one hydroxyl group for interfacial adhesion with a polarizer and an optical film and bonding with a cationically activated epoxy compound, Depending on the number of groups, monofunctional (meth) acrylate, polyfunctional (meth) acrylate, or mixtures thereof. The 'polyfunctional (meth) acrylate' may include two or more (meth) acrylates, for example, 2-6.

Specifically, the monofunctional (meth) acrylate having at least one hydroxyl group is preferably a (meth) acrylate having an alkyl group having 1 to 10 carbon atoms having at least one hydroxyl group, an alicyclic group having at least one hydroxyl group and having 3 to 10 carbon atoms (Meth) acrylate having one or more hydroxyl groups and (meth) acrylate having an aryl group having 6 to 20 carbon atoms having at least one hydroxyl group. For example, the monofunctional (meth) acrylate having at least one hydroxyl group may be selected from the group consisting of 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- (Meth) acrylate, 2-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Acrylate, diethylene glycol mono (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclopentyl (Meth) acrylate, 2-hydroxy-3-phenyloxybutyl (meth) acrylate, and 4-hydroxycyclohexyl (meth) acrylate. The monofunctional (meth) acrylate having at least one hydroxyl group may be contained in an amount of 10 to 25 parts by weight based on 100 parts by weight of the total of (A), (B) and (C), and hydrogen bonding And epoxy curing hatching.

Specifically, the monofunctional (meth) acrylate having no hydroxyl group does not have a hydroxyl group but has a (meth) acrylate group, so that the curing rate can be increased. For example, a monofunctional (meth) acrylate having no hydroxyl group may be a (meth) acrylate having an unsubstituted alkyl group having 1 to 10 carbon atoms, a (meth) acrylate having an unsubstituted alicyclic group having 3 to 10 carbon atoms (Meth) acrylate having an unsubstituted aromatic group having 6 to 20 carbon atoms, and (meth) acrylate having an unsubstituted heteroalicyclic group having 3 to 10 carbon atoms.

(Meth) acrylates having an unsubstituted alkyl group having 1 to 10 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso- (Meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (Meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate.

The (meth) acrylate having an unsubstituted alicyclic group having 3 to 10 carbon atoms may be at least one of cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate.

(Meth) acrylate having an unsubstituted aromatic group having 6 to 20 carbon atoms can be represented, for example, by the following formula (8)

(8)

(Wherein R ⁸ is hydrogen or a methyl group, s is an integer of 0 to 10, R ⁹ is a phenoxy group, a phenyl group, a methylphenyl group, a methylethylphenyl group, a methoxyphenyl group, a propylphenyl group, a cyclohexylphenyl group, A phenyl group, a bromophenyl group, a phenylphenyl group, a benzyl group, and a benzylphenyl group).

The (meth) acrylate having an aromatic group is preferably a phenoxyethyl (meth) acrylate, a phenyl (meth) acrylate, a phenoxy (meth) acrylate, (Meth) acrylate, 2-phenylethyl (meth) acrylate, 3-phenylpropyl (meth) acrylate, 4-phenylbutyl Ethyl (meth) acrylate, 2- (4- (1-methylethyl) phenyl) ethyl (meth) acrylate, 2- Acrylate, 2- (4-methoxyphenyl) ethyl (meth) acrylate, 2- (4-cyclohexylphenyl) ethyl (Meth) acrylate, 2- (4-bromophenyl) ethyl (meth) acrylate, 2- (Meth) acrylate, 2- (3-phenylphenyl) ethyl (meth) acrylate, benzyl (meth) acrylate and 2- But are not limited to these.

The (meth) acrylate having an unsubstituted heteroalicyclic group having 3 to 10 carbon atoms may be n- (meth) acryloylmorpholine.

For example, the monofunctional (meth) acrylate having no hydroxyl group is preferably a (meth) acrylate having an alkyl group having 1 to 10 carbon atoms substituted with an aryloxy group having 6 to 10 carbon atoms, specifically, phenoxyethyl (meth) acrylate .

The monofunctional (meth) acrylate having no hydroxyl group may be contained in an amount of 10 to 25 parts by weight based on 100 parts by weight of the total of (A), (B) and (C) Performance can be expected.

The monofunctional (meth) acrylate having at least one hydroxyl group and the monofunctional (meth) acrylate having no hydroxyl group are contained in the adhesive composition for a polarizing plate at a predetermined weight ratio, thereby increasing the interfacial adhesion and curing rate between the polarizer and the optical film , And the refractive index can be matched. Specifically, the monofunctional (meth) acrylate having at least one hydroxyl group and the monofunctional (meth) acrylate having no hydroxyl group are contained in a weight ratio of 1: 0.5 to 1: 1.5, specifically 1: 0.8 to 1: 1.2 And the above-described effect can be obtained in the above range.

The multifunctional (meth) acrylate can improve the crosslinking density of the radical-cured product to improve the reliability by improving the cohesive energy of the adhesive. The multifunctional (meth) acrylate has 2 or more, preferably 2-6 hydroxyl groups (Meth) acrylate of a polyhydric alcohol having an isocyanurate group, or a (meth) acrylate of a polyhydric alcohol having an isocyanurate group. In an embodiment, the (b2) polyfunctional (meth) acrylate is at least one selected from the group consisting of trimethylolpropane tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, tris (2-acryloxyethyl) isocyanurate , Tris (2-acryloyloxyethyl) isocyanurate, pentaerythritol tri (meth) acrylate, or a mixture thereof.

(Meth) acrylate in the total of 100 parts by weight of (A), (B) and (C) may be included in an amount of 0 to 15 parts by weight.

For example, the (meth) acrylate compound (B) is a (meth) acrylate compound having an alkyl group-containing (meth) acrylate having a hydroxyl group and having 1 to 10 carbon atoms, Acrylate, or a mixture thereof.

(Meth) acrylate compound may be contained in an amount of 10 to 50 parts by weight based on 100 parts by weight of the total of (A), (B) and (C). In the above range, the adhesiveness is not lowered due to the lowering of the cohesive force, the tackiness due to the decrease of the interfacial adhesion and the modulus is not generated, the reliability is not lowered, and the polarizer is not discolored at the time of immersing the hot water. Specifically, 20 to 45 parts by weight may be included in 100 parts by weight of the total of (A), (B) and (C).

The photocationic polymerization initiator may comprise a conventional photocationic initiator capable of carrying out a photocurable reaction. The photocationic polymerization initiator may include an onium salt of an onium ion and an onium salt of an anion. Specific examples of the onium ion include dia, such as diphenyliodonium, 4-methoxydiphenyliodonium, bis (4-methylphenyl) iodonium, bis (4-tert- butylphenyl) iodonium, bis (dodecylphenyl) (Diphenylsulfonium) -phenyl] sulfide, bis [4- ((4-fluorophenylsulfonyl) phenyl] sulfide, triarylsulfonium such as thiodiphenylsulfonium, Phenyl] sulfide, 5-2,4- (cyclopentadienyl) [1,2,3,4,5,6-.eta.] Di (4- (2-hydroxyethyl) - (methylethyl) -benzene] -iron (1+). Specific examples of the anionic examples include tetrakis (pentafluorophenyl) borate _{((C 6 F 5) 4} B -), borates (BF ₄ ^-), tetrafluoroborate, phosphate (PF ₆ ^-), hexafluorophosphate, anti-hexafluoro (SbF ₆ ^- ), hexafluoroarsenate (AsF ₆ ^- ), and hexachloroantimonate (SbCl ₆ ^- ).

The photocationic polymerization initiator may be contained in an amount of 0.1 to 10 parts by weight, for example, 0.1 to 3 parts by weight based on 100 parts by weight of the total of (A), (B) and (C). Within the above range, the polymerization of the epoxy compound can be sufficiently carried out and remaining amount of the initiator can be prevented from remaining.

The adhesive composition for a polarizing plate can be prepared by compounding a fluorene compound containing at least one of an epoxy compound, a (meth) acrylate compound, an epoxy group and a (meth) acrylate group, and introducing a cationic polymerization initiator.

The adhesive composition for a polarizing plate may have a viscosity of 30 to 120 mPa at 25 ° C, and the coating property and the coating property of the optical film may be good in the above range.

The adhesive composition for a polarizing plate may use a predetermined solvent, but it is preferable to use a solventless formulation to reduce the generation of outgas after curing. The adhesive composition for a polarizing plate may contain a conductivity-imparting additive such as an antioxidant, an ultraviolet absorber, an ion-type conductive agent, and a conductive metal oxide fine particle, a light diffusivity-imparting additive, a viscosity modifier, and the like within a range that does not impair the effect of the present invention have.

The adhesive composition for a polarizing plate may have a glass transition temperature after curing of 55 to 105 ° C, specifically, 75 to 105 ° C, and cracks of the PVA (polyvinyl alcohol) polarizer due to shrinkage and expansion between films under the heat shock harsh conditions There may be an effect of inhibiting the generation and growth. The curing includes irradiating light having a wavelength of 200-450 nm and an illuminance of 1-500 mW / cm ² at an irradiation dose of 10-10,000 mJ / cm ² .

Hereinafter, the adhesive composition for a polarizing plate of another embodiment of the present invention will be described.

The adhesive composition for a polarizing plate of another embodiment of the present invention is a fluorene compound containing at least one of (A) an epoxy compound, (B) a (meth) acrylate compound, (C) an epoxy group, D) a photocationic polymerization initiator, and (E) a photosensitizer. By further including a photosensitizer, there is an effect that sufficient curing can be carried out in the case of UV irradiation. Except that the composition further contains a photosensitizer, the photosensitizer will be described below.

The photosensitizer generates a small amount of radicals to catalyze the curing reaction. The adhesive composition for a polarizing plate of the present invention has a heterogeneous hybrid curing structure including both an epoxy compound and a (meth) acrylate compound. The photosensitizer not only cures the (meth) acrylate compound The reactivity of the photocationic polymerization initiator can be improved by serving to catalyze the initiation reaction of the photocationic polymerization initiator necessary for curing of the epoxy compound.

The photosensitizer may include phosphorus, triazine, acetophenone, benzophenone, thioxanthone, benzoin, oxime or mixtures thereof. In embodiments, it may include a thioxantanone or a mixture thereof, a thioxanthene photosensitizer.

The photosensitizer may be added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the total of (A), (B) and (C) (Meth) acrylate-based compound sufficiently cures and may improve the reactivity of the photocationic polymerization initiator.

Hereinafter, an adhesive film for a polarizing plate of one embodiment of the present invention will be described. The adhesive film for a polarizing plate of the embodiment of the present invention may be formed from an adhesive composition for a polarizing plate. Specifically, the adhesive composition for a polarizing plate may be irradiated with light having a wavelength of 200 to 450 nm and an illuminance of 1 to 500 mW / cm ² at an irradiation dose of 10 to 10,000 mJ / cm ² < / RTI >

The adhesive film for a polarizing plate may have a thickness of 10 mu m and a haze of 0 to 20%, preferably 0.2 to 4.5% at a wavelength of 400 to 700 nm. In the above range, even if it is adhered to a polarizer or an optical film, it is transparent and optical transmittance may not be a problem.

The thickness of the adhesive film for a polarizing plate may be 3 占 퐉 or less, preferably 0.1 占 퐉 to 3 占 퐉. In the above range, it can be used as an adhesive film for a polarizing plate.

The adhesive film for a polarizing plate may have a glass transition temperature of 55 to 105 ° C, specifically, 75 to 105 ° C. Within this range, the effect of suppressing the cracking and growth of PVA due to shrinkage and expansion between films under severe thermal shock conditions Can be.

The polarizing plate of the present invention may include an adhesive film formed of an adhesive composition for a polarizing plate of one embodiment of the present invention. Hereinafter, a polarizing plate of one embodiment of the present invention will be described with reference to FIG. 1 is a sectional view of a polarizing plate of one embodiment of the present invention.

1, a polarizer 100 according to an embodiment of the present invention includes a polarizer 110, a first polarizer adhesive film 120 formed on the polarizer 110, and a second polarizer film 120 formed on the first polarizer adhesive film 120. A second polarizing plate adhesive film 140 formed under the polarizer 110 and a second optical film 150 formed under the second polarizing plate adhesive film 140. The first optical film 130, The first polarizing plate adhesive film 120 and the second polarizing plate adhesive film 140 may be formed of an adhesive composition for a polarizing plate of the present invention.

The polarizer can be produced by dying iodine to a film made of a polyvinyl alcohol-based resin and stretching it. As the polyvinyl alcohol-based resin, polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, or a saponified product of an ethylene-vinyl acetate copolymer can be used. The saponification degree of the polyvinyl alcohol-based resin film is 99 or more, preferably 99 to 99.5, and the degree of polymerization is 1000 or more, preferably 2000 to 3000, and the thickness is 5 to 100 m, preferably 5 to 20 m And can be used for the polarizer in the above range.

The first optical film and the second optical film may be at least one of a protective film and a retardation film, but is not particularly limited as long as it is a transparent film.

As a specific example, the protective film may be a non-retardation film such as a cellulose-based film including triacetyl cellulose (TAC), a polyester-based film including polyethylene terephthalate (PET), a cyclic polyolefin (COP )- based film, a polycarbonate , Polyacrylate type, polyether sulfone type, polysulfone type, polyamide type, polyimide type, polyolefin type, polyarylate type, polyvinyl alcohol type, polyvinyl chloride type, polyvinylidene chloride type or mixtures thereof A film made of a material selected from the group consisting of

The retardation film can be used without restriction as long as the retardation film is a film having a? / 2 or? / 4 retardation function. For example, a film made of an olefinic, acrylic, cellulose, or a mixture thereof including a cycloolefin polymer (COP) can be used.

The first optical film and the second optical film may be subjected to a surface treatment, for example, a corona pre-treatment step of 250 mJ / cm ² or more before the application of the adhesive composition or before the preparation of the polarizing plate.

Each of the first optical film and the second optical film may have a thickness of 25 탆 to 500 탆. In the above range, it can be used as a polarizing plate when laminated on a polarizing element. And preferably 25 占 퐉 to 100 占 퐉.

The polarizing plate can be produced by a conventional method. For example, an adhesive composition for a polarizing plate is applied to one side of a protective film to produce a protective film having an adhesive composition layer. Drying and the like can be carried out if necessary. As the coating method, for example, a die coating method, a roll coating method, a gravure coating method and a spin coating method can be used. A protective film having the above-mentioned adhesive composition layer is laminated on each of the upper and lower surfaces of the polarizer to obtain a laminate. The adhesive layer is formed by curing the adhesive composition layer by irradiating ultraviolet rays, from which the polarizing plate can be produced. Ultraviolet irradiation can be performed by irradiating light having a wavelength of 200-450 nm and an illumination of 1-500 mW / cm ² at an irradiation dose of 10-10,000 mJ / cm ² .

The optical display device of the present invention may include the polarizer adhesive composition, the adhesive film formed of the adhesive composition, or a polarizer including the same. The optical display device is a conventional optical display device including a polarizing plate, and may include, for example, a liquid crystal display or the like. 2 is a cross-sectional view of an optical display device according to an embodiment of the present invention.

2, an optical display device 200 according to an embodiment of the present invention includes a liquid crystal panel 210, a first polarizer 220 formed on the liquid crystal panel 210, and a second polarizer 220 formed below the liquid crystal panel 220. [ And a polarizer 230. At least one of the first polarizer 220 and the second polarizer 230 may be a polarizer of the present invention.

Hereinafter, the present invention will be described in more detail by way of examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Specific specifications of the components used in Examples and Comparative Examples are as follows.

(A) epoxy system: (A1) Bisphenol F epoxy (KDS-8170, Kukdo Chemical), (A2) Aliphatic cycloepoxy (SEE-4221, Seechem)

(B1) 4-Hydroxybutyl acrylate (100%, Osaka Organic (JAPAN)), (B2) Phenoxyethyl acrylate (M140, Miwon)

(C) Fluorene compound: (C1) EG-200 (BPEF Epoxy, Osaka Gas, epoxy equivalent: 292 g / eq), (C2) EA-F5003 (BPEF Acrylate, Osaka Gas)

(D) Gwangyang Ion Polymerization Initiator: Triarylsulfonium hexaflouroantimonate salt (CPI-100P, Sanapro)

(E) Photosensitizer: Diethylthioxanthone (DETX-S, Nipponkayaku)

Example  1 to 7 and Comparative Example  One

An epoxy compound, a (meth) acrylic compound and a fluorene compound were blended in the amounts described in Table 1 (unit: parts by weight) without a solvent. And 1 part by weight of a cationic polymerization initiator and 2 parts by weight of a photosensitizer were mixed and mixed to prepare an adhesive composition for a polarizing plate.

A B C A1 A2 B1 B2 C1 C2 Example 1 50 - 22.5 22.5 5 - Example 2 50 - 20 20 10 - Example 3 75 - 10 10 5 - Example 4 - 75 10 10 5 - Example 5 50 - 22.5 22.5 - 5 Example 6 50 - 20 20 - 10 Example 7 50 - 20 20 5 5 Comparative Example 1 40 - 60 - - -

Production of Polarizer

A polyvinyl alcohol film (degree of saponification: 99.5, degree of polymerization: 2000) having a thickness of 80 mu m was used as the base film. The base film was immersed in an aqueous 0.3% iodine solution, and then drawn to give a draw ratio of 5.0. Subsequently, the stretched substrate film was immersed in a boric acid solution of 3% concentration and an aqueous solution of 2% potassium iodide to perform color correction, followed by drying at 50 DEG C for 4 minutes to prepare a polarizer (thickness 25 mu m).

The first was used as a polyethylene terephthalate (PET) film having a thickness 80㎛ the protective film was a corona-treated at least 250 mJ / cm ^2. As the second protective film, a cycloolefin resin having a thickness of 30 占 퐉 was subjected to a corona treatment at 250 W.min / m ² or more using a resin that was polymerized using cyclic olefin as a polymerization unit.

A first protective film under the environment of a temperature of 22 to 25 ° C and a humidity of 20 to 60%, an adhesive composition of Examples or Comparative Examples, a polarizer, an adhesive composition of a comparative example and a second protective film, by irradiation with ^{Metal halide lamp) 400mW / cm 2} , 1000 mJ / cm 2 to the condition, a polarizing plate (thickness 140㎛) .

The following properties of the adhesive composition or polarizing plate for a polarizing plate of Examples and Comparative Examples were evaluated and shown in Table 2.

(1) Viscosity: The adhesive composition for a polarizing plate was measured for viscosity at 25 캜 and 30 rpm using a Brookfield viscometer (RV II) No. 61 Spindel and expressed as mPa value.

(2) Polarizer crack length due to thermal shock: A double-side tape was attached to a glass, and a polarizing plate of 100 mm x 100 mm (width x length) was laminated on a glass to prepare a sample. The sample was cycled between -40 DEG C and 65 DEG C for 1 cycle of low temperature and high temperature, and 200 cycles were added to the polarizing plate to give a thermal shock. The crack length from the end of the polarizer to the polarizer MD (machine direction) in the reflection mode under fluorescent lamps was measured.

(3) Adhesion force: In order to confirm the adhesion of the polarizing plate adhesive film, a polarizing plate having a size of 100 mm x 100 mm (width x length) was inserted with a cutter tip between the protective film at the end and the polarizer, Was applied to both sides of UTM (TA XT Plus, Texture Technologies) and peeled at a rate of 300 mm / min. Peeling samples between the PET and PVA surfaces were recorded with PET surface adhesion, and peel samples between PVA and COP surfaces were recorded with COP cotton adhesion.

(4) Glass transition temperature (Tg): the release polyethylene terephthalate film sprinkled with the adhesive composition for a polarizing plate between 2 roughness of 300mw / cm ^2, a film laminated with Handy Roll with a suitable speed to Metal halide Lamp with 800mj / cm ² Lt; / RTI > About 5 mg of the adhesive film for a polarizing plate was sampled by rounding. The sampled adhesive was mounted on a DSC thermal analyzer, and the temperature was elevated from 0 ° C to 200 ° C at a rate of 10 ° C per minute, and the inflection point of the analyzed absorption / heating peaks was recorded as Tg.

Viscosity (mPa) Polarizer crack length due to thermal shock (mm) Adhesion (N / 25mm) Tg (占 폚) PET cotton COP cotton Example 1 73 4.3 4.5 2.3 79 Example 2 98 3.6 2.8 1.7 101 Example 3 89 2.1 Substrate destruction * Substrate breakdown 85 Example 4 70 2.9 3.7 Substrate breakdown 75 Example 5 82 3.7 3.1 1.9 90 Example 6 95 2.3 2.6 3.5 95 Example 7 93 2.9 2.4 1.8 98 Comparative Example 1 20 Front crack 1.6 0.9 42

* Substrate breakdown: Strong adhesive force means that the PET or COP film is broken when measuring the adhesive strength.

As shown in Table 2, the adhesive composition for a polarizing plate of the present invention has a viscosity of a predetermined range, and thus has good coating and coating properties and good adhesion to hydrophobic protective films. In addition, the adhesive film formed of the adhesive composition for a polarizing plate of the present invention has a glass transition temperature within a predetermined range, so that cracking of the polarizer and growth of the polarizer can be suppressed under severe thermal shock conditions.

On the other hand, it was confirmed that the adhesive composition for a polarizing plate of Comparative Example 1 containing no fluorene compound had weak adhesion to a hydrophobic protective film, and a front crack occurred in a polarizer under a severe thermal shock condition.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (15)

(A) an epoxy compound, (B) a (meth) acrylate compound, (C) a fluorene compound containing at least one of an epoxy group and a (meth) acrylate group, and Adhesive composition for a polarizing plate. The adhesive composition for a polarizing plate according to claim 1, wherein the fluorene compound (C)
≪ Formula 1 >

(Wherein R ¹ is hydrogen, a hydroxyl group, a phenyl group, an amino group, a tolyl group, a carboxylic acid group or an alkyl group having 1 to 10 carbon atoms,
R ² is * -O- (C = O) -C (A) = CH 2, * - (B) -O- (C = O) -C (A) = CH 2, * -O- (B) -O- (C = O) -C ( a) = CH 2 to, formula 2, formula 3, the formula 4, Chemical formula 5, Chemical formula 6, or to a formula (7)
(2)

(3)

≪ Formula 4 >

≪ Formula 5 >

(6)

≪ Formula 7 >

(Wherein * is a connection portion of the element, A is hydrogen or a methyl group, B is an alkylene group having 1 to 20, R ⁷ is hydrogen or a methyl group, p is an integer of 1 to 10)
R ³ , R ⁴ , R ⁵ and R ⁶ are each independently hydrogen, cyano, an alkyl group having 1 to 10 carbon atoms or halogen,
m is an integer of 0 to 4, n is an integer of 1 to 5, and m + n is 5). The adhesive composition for a polarizing plate according to claim 1, wherein the fluorene compound containing an epoxy group has an epoxy equivalent of 250 to 450 g / eq. The adhesive composition for a polarizing plate according to claim 1, wherein the fluorene compound (C) has a bisphenoxyethanol fluorene moiety. The adhesive composition for a polarizing plate according to claim 1, wherein the weight ratio of the (meth) acrylate compound to the fluorene compound containing the (meth) acrylate group in the adhesive composition is 4 to 15. The adhesive composition for a polarizing plate according to claim 1, wherein the weight ratio of the epoxy compound to the fluorene compound containing the epoxy group in the adhesive composition is 4 to 15. The adhesive composition for a polarizing plate according to claim 1, wherein the epoxy compound (A) comprises an alicyclic epoxy compound, an aromatic epoxy compound, an aliphatic epoxy compound, a hydrogenated epoxy compound, or a mixture thereof. The composition according to claim 1, wherein the (meth) acrylate compound (B) is at least one compound selected from the group consisting of a (meth) acrylate having an alkyl group of 1 to 10 carbon atoms having a hydroxyl group and an alkyl group having 1 to 10 carbon atoms having an aryloxy group having 6 to 10 carbon atoms Containing (meth) acrylate, or a mixture thereof. The positive resist composition according to claim 1, wherein 40 to 85 parts by weight of (A), 10 to 50 parts by weight of (B), and 10 to 50 parts by weight of (C) are contained in 100 parts by weight of the total of (A) ) Is contained in an amount of 1 to 25 parts by weight. The adhesive composition for a polarizing plate according to claim 1, wherein the adhesive composition for a polarizing plate further comprises (E) a photosensitizer. The positive resist composition according to claim 10, wherein (D) is contained in an amount of 0.1 to 10 parts by weight, and (E) is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total of (A), (B) Adhesive composition for a polarizing plate. The adhesive composition for a polarizing plate according to claim 1, wherein the adhesive composition for a polarizing plate has a glass transition temperature of 55 to 105 ° C after curing. An adhesive film for a polarizing plate formed from the adhesive composition for a polarizing plate according to any one of claims 1 to 12. 14. A polarizing plate comprising the adhesive film for a polarizing plate according to claim 13. An optical display device comprising the polarizing plate of claim 1

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