KR20180111227A - Polarizing plate and image display device comprising the same - Google Patents

Abstract

The present invention relates to a polarizing plate, and more specifically, to a polarizing plate, which comprises: a polarizer; and an adhesive layer laminated on at least one surface of the polarizer, wherein the adhesive layer realizes excellent adhesion durability and reliability even under severe conditions (high temperature and high humidity), and at the same time, has excellent reworkability by satisfying a specific formula, thereby being capable of ensuring excellent durability.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and an image display device including the polarizing plate.

The present invention relates to a polarizing plate and an image display apparatus including the same.

A liquid crystal display device (LCD) is provided with a liquid crystal cell and a liquid crystal panel including a polarizing plate laminated on both sides of the liquid crystal cell.

Generally, the polarizing plate comprises a protective film typified by iodine polyvinyl alcohol (PVA) polarizer and triacetyl cellulose (TAC) for protecting both surfaces of the polarizer. More specifically, a multilayer structure in which a protective film and, if necessary, a surface protective film are laminated in order on one side of a polarizer, and a protective film, an adhesive layer for bonding with a liquid crystal cell and a release film are laminated in order on the other side .

The pressure-sensitive adhesive for bonding with a liquid crystal cell must satisfy both durability such as heat resistance and heat resistance, and reheat property. However, since the properties of the pressure-sensitive adhesive required for satisfying these properties are contradictory, It is not completely solved.

Korean Patent Laid-Open Publication No. 2011-0103321 discloses a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet, but fails to provide an alternative to the above-mentioned problems.

Korea Patent Publication No. 2011-0103321

An object of the present invention is to provide a polarizing plate comprising a pressure-sensitive adhesive layer which exhibits excellent adhesion durability and reliability even under severe conditions (high temperature and high humidity) and which has excellent reworkability.

Another object of the present invention is to provide an image display apparatus including the above-mentioned polarizing plate.

1. polarizer; And a pressure-sensitive adhesive layer laminated on at least one surface of the polarizer, wherein the polarizer satisfies the following formula (1): " (1) "

[Equation 1]

(A / B) X (C / D) > 1.0

(Where A is the thickness of the adhesive layer, B is the thickness of the polarizer, C is the adhesive layer is attached to a glass plate having an adhesion area of 1.0 cm < And D is the distance that the adhesive layer is pushed when the adhesive layer is attached to a glass plate having an adhesive area of 1.0 cm X 1.0 cm and a load of 1 kgf is applied at 85 ° C for 1000 seconds.

2. The polarizer of claim 1, further comprising a protective film laminated on at least one surface of the polarizer, wherein the adhesive layer is laminated on the opposite surface of the protective film to which the polarizer is adhered.

3. The polarizing plate of claim 1, wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition comprising an acrylic copolymer and an isocyanate-based crosslinking agent polymerized with a compound represented by Formula 1:

[Chemical Formula 1]

,

,

또는

이고, R₄는 수소,

,

또는

이고, X는

또는

이고, Y는 단일결합, 메틸렌기,

,

또는

이고, R₅는 탄소수 6 내지 20의 아릴기 또는 탄소수 7 내지 12의 아릴알킬기이고, R₆, R₇ 또는 R₈은 각각 독립적으로 수소, 탄소수 1 내지 12의 알킬기, 탄소수 1 내지 12의 알케닐기, 탄소수 6 내지 20의 아릴기 또는 탄소수 7 내지 12의 아릴알킬기이며, *는 결합 부위임).(Wherein R ₁ is hydrogen or an alkyl group having 1 to 3 carbon atoms, R ₂ is an alkylene group having 1 to 20 carbon atoms, and R ₃ is

,

,

or

, R < ₄ > is hydrogen,

,

or

And X is

or

Y is a single bond, a methylene group,

,

or

, R ₅ is an aryl group having 6 to 20 carbon atoms or an arylalkyl group having 7 to 12 carbon atoms and R ₆ , R ₇ or R ₈ are each independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms , An aryl group having 6 to 20 carbon atoms or an arylalkyl group having 7 to 12 carbon atoms, and * is a bonding site).

4. The polarizer of claim 3, wherein the acrylic copolymer is polymerized in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer.

5. The polarizer according to 3 above, wherein the acrylic copolymer further comprises a carboxyl group-containing (meth) acrylate monomer.

6. The composition of claim 5, wherein the carboxyl group-containing (meth) acrylate monomer is selected from the group consisting of (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylsuccinic acid, Wherein the polarizer is at least one selected from the group consisting of carboxypolycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyltetrahydrophthalic acid.

(7) The polarizer according to (5), wherein the acrylic copolymer is polymerized by incorporating not more than 5 parts by weight of the carboxyl group-containing (meth) acrylate monomer based on 100 parts by weight of the acrylic copolymer.

8. The polarizer according to item 3 above, wherein the acrylic copolymer further comprises a crosslinkable monomer.

9. The polarizing plate according to item 8, wherein the crosslinkable monomer is at least one selected from the group consisting of a monomer having a hydroxyl group or a monomer having an amide group.

10. The polarizer of claim 8, wherein the acrylic copolymer is polymerized with 1 to 8 parts by weight of the crosslinkable monomer based on 100 parts by weight of the acrylic copolymer.

11. The polarizer of claim 3, wherein the pressure-sensitive adhesive composition further comprises an ionic antistatic agent.

12. An image display device comprising any one of the polarizing plates 1 to 11 above.

The polarizing plate of the present invention can ensure excellent durability including a pressure-sensitive adhesive layer having excellent reworkability while realizing superior adhesion durability and reliability even under severe conditions (high temperature and high humidity).

1 is a schematic view for explaining a polarizing plate of embodiments of the present invention.

The present invention relates to a polarizing plate, and more particularly, to a polarizing plate, And a pressure-sensitive adhesive layer laminated on at least one surface of the polarizer, wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive layer which satisfies the following formula (1) and exhibits excellent pressure-resistance durability and reliability even under severe conditions (high temperature and high humidity) To a polarizing plate capable of ensuring excellent durability.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. While the following preferred embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as defined by the following claims. It will be obvious to those skilled in the art that such modifications and variations are within the scope of the appended claims.

1 is a view for explaining a polarizing plate according to embodiments of the present invention.

Referring to FIG. 1, the polarizer includes a polarizer 10 and an adhesive layer 20 laminated on at least one side of the polarizer 10. For example, the adhesive layer 20 may be a layer for bonding or attaching a polarizing plate to another substrate necessary for manufacturing an image display device such as a liquid crystal cell, a touch panel, or the like.

The polarizer 10 may be obtained by swelling, dyeing, crosslinking, stretching, washing with water, and drying a polarizer-forming film ordinarily used in the art.

The polarizer 10 according to the present invention may be a polarizer commonly used in the art which is manufactured according to a process including a step of swelling, dyeing, crosslinking, stretching, washing, drying, and the like.

The polarizer-forming film is not particularly limited as long as it is a dichroic material, that is, a film that can be dyed with iodine. For example, a polyvinyl alcohol film, a dehydrated polyvinyl alcohol film, a dehydrochlorinated polyvinyl alcohol film , A polyethylene terephthalate film, an ethylene-vinyl acetate copolymer film, an ethylene-vinyl alcohol copolymer film, a cellulose film, and partially saponified films thereof. Of these, a polyvinyl alcohol-based film is preferable because it has an excellent effect of enhancing the uniformity of the degree of polarization in the plane and is excellent in dye affinity for iodine.

The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith.

Other monomers copolymerized with vinyl acetate are generally used in the art and are not limited as long as they do not deviate from the object of the present invention. Specific examples thereof include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, For example.

The modified polyvinyl alcohol resin may be a modified polyvinyl alcohol resin. Specific examples thereof include polyvinyl formal and polyvinyl acetal modified with aldehydes.

The degree of saponification of the polyvinyl alcohol-based resin may be 85 to 100 mol%, preferably 98 to 100 mol%, and the degree of polymerization of the polyvinyl alcohol-based resin may be 1,000 to 10,000, preferably 1,500 to 5,000 .

The thickness of the polarizer-forming film is not particularly limited, and may be, for example, 5 to 50 탆, and preferably 15 to 30 탆. And is preferable in view of the improvement of the mechanical durability and the realization of the thin film device when it is in the above range.

The polarizing plate according to the embodiments satisfies the following formula (1).

[Equation 1]

(A / B) X (C / D) > 1.0

In the formula (1), A is the thickness of the adhesive layer 20, B is the thickness of the polarizer 10, C is the adhesive layer 20 is attached to a glass plate having an adhesion area of 1.0 cm & The adhesive layer 20 is attached to a glass plate having an adhesive area of 1.0 cm x 1.0 cm and a load of 1 kgf is applied at 85 DEG C for 1000 seconds And the distance that the adhesive layer 20 is pushed.

The polarizing plate satisfying the above-described formula (1) has a thickness of the polarizer (10) and the pressure-sensitive adhesive layer (20) and a holding power of the pressure-sensitive adhesive layer at room temperature and high temperature . ≪ / RTI > Therefore, the polarizing plate of the embodiment satisfying the above-mentioned formula (1) can include an adhesive layer which realizes not only room temperature but also durability and reliability under severe and humid conditions, and at the same time secures excellent reworkability. Mechanical properties can also be improved at the same time.

The pushing distance can be obtained, for example, by appropriately adjusting the composition, composition and the like of the pressure-sensitive adhesive composition capable of forming the pressure-sensitive adhesive layer (20).

The adhesive layer 20 is laminated on at least one surface of the polarizer 10. For example, the adhesive layer 20 may be laminated or formed on one side or both sides of the polarizing plate, but is not limited thereto. The adhesive layer 20 may be a layer formed or laminated on a polarizing plate and formed for adhesion or lamination with a polarizing plate and another substrate necessary for manufacturing an image display device.

The adhesive layer 20 may be directly adhered or laminated on the polarizer 10, but it is not limited that the other substrate is interposed between the polarizer 10 and the adhesive layer 20. For example, one or more layers providing additional functions such as a protective layer, a reflective layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a luminance enhancement film may be interposed or laminated between the polarizer 10 and the adhesive layer 20 .

In some embodiments, the adhesive layer 20 may be formed by applying a pressure sensitive adhesive composition onto a polarizer and drying or curing. The pressure-sensitive adhesive composition that can be used in the present invention is not particularly limited as long as it can satisfy the above-mentioned formula (1). For example, the pressure-sensitive adhesive composition includes an acrylic copolymer and an isocyanate Based crosslinking agent.

[Chemical Formula 1]

,

,

또는

이고, R₄는 수소,

,

또는

이고, X는

또는

이고, Y는 단일결합, 메틸렌기,

,

또는

이고, R₅는 탄소수 6 내지 20의 아릴기 또는 탄소수 7 내지 12의 아릴알킬기이고, R₆, R₇ 또는 R₈은 각각 독립적으로 수소, 탄소수 1 내지 12의 알킬기, 탄소수 1 내지 12의 알케닐기, 탄소수 6 내지 20의 아릴기 또는 탄소수 7 내지 12의 아릴알킬기이며, *는 결합 부위이다.Wherein R ₁ is hydrogen or an alkyl group having 1 to 3 carbon atoms, R ₂ is an alkylene group having 1 to 20 carbon atoms, R ₃ is

,

,

or

, R < ₄ > is hydrogen,

,

or

And X is

or

Y is a single bond, a methylene group,

,

or

, R ₅ is an aryl group having 6 to 20 carbon atoms or an arylalkyl group having 7 to 12 carbon atoms and R ₆ , R ₇ or R ₈ are each independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms , An aryl group having 6 to 20 carbon atoms or an arylalkyl group having 7 to 12 carbon atoms, and * is a bonding site.

The pressure-sensitive adhesive composition includes an acrylic copolymer polymerized by including the compound represented by the formula (1). The compound represented by the formula (1) can produce α-carbon having high nucleophilicity due to an excellent electron-withdrawing group of R ₃ or R ₄ , It is possible to impart excellent durability to the pressure-sensitive adhesive layer or pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition containing the acrylic copolymer containing the acrylic copolymer. In addition, the above-described durability is satisfied and the reworkability is not lowered, which is very suitable for forming an adhesive layer of a polarizing plate satisfying the above-mentioned formula (1), and is preferable in securing excellent mechanical properties.

Preferably, R ₁ in the formula (1) may be hydrogen or a methyl group, and R ₂ may be an alkylene group having 1 to 8 carbon atoms in terms of preventing degradation of crosslinking efficiency due to steric hindrance.

,

또는

일 수 있고, R₄는 수소,

,

또는

일 수 있으며, 보다 바람직하게는 알파 탄소의 친핵성도를 높여 추가 가교 반응을 더욱 활성화 시키면서도 입체 장애로 인한 가교 효율 저하를 방지한다는 측면에서 R₃은

일 수 있고, R₄는 수소 또는

일 수 있다.Preferably, in view of further enhancing the nucleophilicity of the alpha carbon due to the strong electron withdrawing group, R < ₃ >

,

or

And R < ₄ > is hydrogen,

,

or

And more preferably, in view of increasing the nucleophilicity of the alpha carbon to further activate the additional crosslinking reaction and prevent the degradation of the crosslinking efficiency due to the steric hindrance, R < ₃ >

And R < ₄ > is hydrogen or

Lt; / RTI >

의 결합 부위와 관련하여, R₂와 결합한 결합 부위의 위치는 특별하게 제한되지 않으며, 바람직하게는 Y와 인접한 알파 탄소의 친핵성도를 더 향상시킴으로써 추가적인 가교 반응을 더 촉진시킨다는 측면에서, 카보닐 탄소와 인접한 결합 부위에 R₂가 결합 또는 연결되는 것이 좋다.Illustrated in Y

With respect to the bonding site of R ₂ , there is no particular limitation on the position of the bonding site bonded with R _2, and preferably from the viewpoint of further promoting the additional crosslinking reaction by further improving the nucleophilicity of the alpha carbon adjacent to Y, And R < _{2 >} are bonded or connected to the adjacent bonding sites.

For example, the compound represented by Formula 1 may be illustrated by the following Formulas 1-1 to 1-4.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

As used herein, the term "alkyl group " encompasses straight or branched chain alkyl groups, wherein the" aryl group "is derived from an aromatic hydrocarbon by removal of one hydrogen, suitably from 4 to 7, Includes a single or fused ring system containing 5 or 6 ring atoms, and is a concept including a form in which a plurality of aryls are connected by a single bond. For example, the aryl group may be an aryl group having 6 to 20 carbon atoms.

The acrylic copolymer may be polymerized in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the acrylic copolymer. When the amount is less than 0.1 part by weight, the adhesion durability, reliability and / or the workability improving effect may be insufficient. When the amount is more than 10 parts by weight, the additional crosslinking reaction may proceed to some extent excessively, and the hardness of the formed pressure- have.

In one embodiment, the acrylic copolymer may further include an additional (meth) acrylate monomer in addition to the compound represented by Formula (1). Here, (meth) acrylate means acrylate or (meth) acrylate.

The (meth) acrylate monomer is not particularly limited as long as it can be generally used in the pressure-sensitive adhesive composition of the related art, and may be, for example, a (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms.

Examples of the (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, (Meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (Meth) acrylate, nonyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate and lauryl (meth) acrylate. Of these, n-butyl acrylate, Mixtures of these are preferred. These may be used alone or in combination of two or more.

The (meth) acrylate monomer having an alkyl group having 1 to 12 carbon atoms is preferably contained in an amount of 77 to 98.9 parts by weight based on 100 parts by weight of the total monomers used in the production of the acrylic copolymer. When the content is less than 77 parts by weight, the adhesive force may not be sufficient and the release film peeling force may be increased. When the content exceeds 98.9 parts by weight, the cohesive strength may be lowered and the durability may be deteriorated.

In one embodiment, the acrylic copolymer may further include a crosslinkable monomer capable of copolymerizing with the compound represented by Formula 1 and / or the additional (meth) acrylate monomer.

Examples of the crosslinkable monomer include monomers having a hydroxyl group and / or monomers having an amide group.

Specific examples of the monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, hydroxyalkyl Hydroxypropyl vinyl ether, 6-hydroxyhexyl vinyl ether, 7-hydroxyheptyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxybutyl vinyl ether, Hydroxynonyl vinyl ether, 10-hydroxydecyl vinyl ether, and the like.

Examples of the monomer having an amide group include (meth) acrylamide, N-isopropylacrylamide, N-tertiary butyl acrylamide, 3-hydroxypropyl (meth) acrylamide, 4-hydroxybutyl (Meth) acrylamide, 8-hydroxyoctyl (meth) acrylamide and 2-hydroxyethylhexyl (meth) acrylamide. Of these, (meth) acrylamide is preferable.

The crosslinkable monomer is preferably contained in an amount of 0.05 to 10 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of the acrylic copolymer. When the content is within the above range, the cohesive force and durability of the pressure-sensitive adhesive are excellent.

Further, in addition to the above monomers, other polymerizable monomers known in the art may be further added in such a range as not to lower the adhesive force, for example, 10 parts by weight or less.

In one embodiment, the acrylic copolymer may further include a compound represented by the above-described formula (1) or a carboxyl group-containing (meth) acrylate monomer copolymerizable with the (meth) acrylate monomer. The acrylic copolymer further includes the carboxyl group-containing (meth) acrylate monomer and is polymerized to improve the strength, durability, and the like of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet.

Examples of the carboxyl group-containing (meth) acrylate monomers include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- ) Acryloyloxyethylsuccinic acid, carboxypolycaprolactone mono (meth) acrylate or 2- (meth) acryloyloxyethyltetrahydrophthalic acid, which may be used alone or in combination of two or more. Preferably, the carboxyl group-containing (meth) acrylate monomer may be (meth) acrylic acid.

The acrylic copolymer may be polymerized with 5 parts by weight or less of the carboxyl group-containing (meth) acrylate monomer based on 100 parts by weight of the acrylic copolymer, preferably 0.5 to 3 parts by weight, have. If the amount is more than 5 parts by weight, corrosion of facilities due to acid may occur.

The method for producing the acrylic copolymer is not particularly limited, and can be produced by methods such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization, which are commonly used in the art, and solution polymerization is preferred. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control and the like which are usually used in polymerization can be used.

The acrylic copolymer has a weight average molecular weight (in terms of polystyrene, Mw) of 500,000 to 2,000,000, preferably 500,000 to 1,700,000, and more preferably 80,000,000, as measured by Gel Permeation Chromatography (GPC) To 1.7 million in terms of improving the durability and reliability of the adhesive layer.

The pressure-sensitive adhesive composition of the present invention may further comprise a crosslinking agent. The crosslinking agent further improves the adhesion and durability, and can maintain the reliability at a high temperature and the shape of the pressure-sensitive adhesive.

The crosslinking agent of the present invention may specifically include an isocyanate crosslinking agent in terms of improving durability, and it is preferable that the crosslinking agent of the present invention has excellent compatibility with the acrylic copolymer polymerized with the compound represented by the formula (1) It is preferable in terms of further improvement.

Examples of the isocyanate crosslinking agent include tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, Diisocyanate compounds such as isocyanate and naphthalene diisocyanate; An adduct obtained by reacting 3 equivalents of a diisocyanate compound with 1 equivalent of a polyhydric alcohol compound such as trimethylolpropane, an isocyanurate compound in which 3 equivalents of a diisocyanate compound is self-condensed, a diisocyanate obtained from 2 equivalents in 3 equivalents of a diisocyanate compound, A multifunctional isocyanate compound containing three functional groups such as burette, triphenylmethane triisocyanate and methylene bistriisocyanate in which the remaining one equivalent of diisocyanate is condensed in urea; , But are not limited thereto. In one embodiment, the crosslinking agent is preferably tolylene diisocyanate in view of further improving heat resistance and heat and moisture resistance.

The content of the cross-linking agent is not particularly limited within a range where the function of the cross-linking agent can be accomplished. For example, the amount of the cross-linking agent may be 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer. If the content is less than 0.1 part by weight, the cohesive force becomes small due to insufficient crosslinking, which may impair the physical properties of the durability and cutability. If the content is more than 10 parts by weight, the residual stress due to the excessive crosslinking reaction may be deteriorated.

The crosslinking agent may further include a crosslinking agent known in the art in addition to the isocyanate crosslinking agent. Examples of the crosslinking agent include epoxy, metal chelating, polyfunctional acrylate, and oxazoline. Any combination of species can be used.

In addition to the isocyanate crosslinking agent, melamine derivatives such as hexamethylol melamine, hexamethoxymethyl melamine, hexabutoxymethyl melamine and the like; Polyepoxy compounds, for example, bisphenol A and epichlorohydrin condensate type epoxy compounds; At least one crosslinking agent selected from the group consisting of polyglycidyl ether of polyoxyalkylene polyol, glycerin di- or triglycidyl ether, and tetraglycidyl xylenediamine may be further added and used together.

In one embodiment, the pressure-sensitive adhesive composition may further include an antistatic agent.

The antistatic agent may be, for example, an ionic antistatic agent. For example, the ionic antistatic agent may include at least one of an alkali metal cation and an onium cation, and at least one anion among a fluorine-containing inorganic anion and a fluorine-containing organic anion. In such a case, compatibility with the above-mentioned other components, durability and antistatic property are excellent.

The alkali metal cation is lithium, sodium, potassium or potassium; The onium cation is a quaternary alkyl ammonium, pyridinium or imidazolium; The fluorine-containing inorganic anion is BF ₄ ^- , PF ₆ ^- or SbF ₆ ^- ; The fluorine-containing organic anion may be a sulfonate including a perfluoroalkyl group, a sulfonylimide anion including a perfluoroalkyl group or a fluoro group, but is not limited thereto. For example, the antistatic agent is preferably potassium bisfluorosulfonylimide in view of ensuring antistatic property and durability at the same time.

The alkyl group in the alkyl ammonium or perfluoroalkyl group may be an alkyl group having 1 to 4 carbon atoms.

The content of the ionic antistatic agent is not particularly limited and may be, for example, 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer. When the content is less than 0.1 part by weight, the antistatic property may be insufficient, and when it is more than 10 parts by weight, it may be difficult to secure durability.

In one embodiment, the pressure-sensitive adhesive composition may further include a silane coupling agent if necessary.

The kind of the silane coupling agent is not particularly limited, and examples thereof include vinylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- 3-glycidoxypropyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, Acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane , N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) Methyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3- 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatepropyltriethoxysilane, substituted acetamide group-containing silane, and the like. However, It is preferable to use 3-glycidoxypropyltrimethoxysilane to simultaneously satisfy the workability. These may be used alone or in combination of two or more.

The silane coupling agent may be contained in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the copolymer based on the solid content. If the content exceeds 10 parts by weight, the durability may be lowered.

The pressure-sensitive adhesive composition of the present invention may further contain additives such as a tackifier resin, an antioxidant, a corrosion inhibitor, a leveling agent, a surface lubricant, a defoaming agent, a filler, A light stabilizer, a reaction initiator, a solvent, and the like.

The thickness of the adhesive layer 20 is not particularly limited and may be, for example, 5 to 50 占 퐉, and preferably 15 to 30 占 퐉. In the above range, the durability and reliability of the adhesive layer 20 can be improved, and in view of durability and thin film implementation of the polarizing plate including the same.

The polarizing plate according to one embodiment may further include a protective film 30 laminated on at least one side of the polarizer 10 as shown in FIG. In this case, the adhesive layer 20 may be laminated or formed on the protective film 30, and may be formed on the opposite side of the surface to which the polarizer 10 of the protective film 30 is adhered, for example.

For example, the protective film 30 may be laminated between the polarizer 10 and the adhesive layer 20. Further, the protective film 30 may be adhered to one surface or both surfaces of the polarizer.

The type of the protective film 30 is not particularly limited as long as it is a transparent plastic film, and it is preferable that the protective film 30 is excellent in mechanical strength, thermal stability, moisture barrier property, isotropy, etc., in addition to transparency.

Specific examples of the protective film 30 include polyester films such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based films such as diacetylcellulose, triacetylcellulose, acetylcellulose butylate, isobutylester cellulose, propionylcellulose, butyrylcellulose, and acetylpropionylcellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene-based films such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin-based films such as polyethylene, polypropylene, cyclo-based or norbornene-based polyolefin-based films, and ethylene propylene copolymers; Ethylene-vinyl acetate copolymer film; Polyamide film; Polyimide, polyetherimide film; Polyethersulfone-based films; Sulfone based films; Polyvinyl chloride, polyvinylidene chloride film; Polyvinyl alcohol, polyvinyl acetal film; Polyetherketone, polyetheretherketone film; Polyurethane, epoxy film and the like. These may be unoriented, uniaxial or biaxially oriented films. Of these, monoaxially or biaxially oriented polyester films, polymethylmethacrylate films or polycycloolefin-based films superior in transparency and heat resistance, and triacetyl cellulose and isobutyl ester cellulose films in terms of transparency and optical anisotropy desirable.

And may be 10 to 200 탆 of the protective film 30. Though the thickness of the protective film is preferably small, if it is too thin, the strength is lowered and the workability is lowered. If it is too thick, the transparency is lowered or the weight of the polarizing plate is increased.

The present invention also provides an image display device including the above-mentioned polarizing plate.

The image display apparatus of the present invention may further include a configuration known in the art in addition to the polarizing plate.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Example

(1) Production of acrylic copolymer

Nitrogen gas was refluxed and a 1 L reactor equipped with a cooling device for easy temperature control was charged with 76.5 parts by weight of n-butyl acrylate, 20 parts by weight of methyl acrylate, 2.0 parts by weight of 2-hydroxyethyl acrylate, 1.0 part by weight of methoxyethyl methacrylate (refer to Chemical Formula 1-1) and 0.5 part by weight of acrylic acid, and then 100 parts by weight of ethyl acetate was added as a solvent. Nitrogen gas was then purged for 1 hour to remove oxygen and then maintained at 62 ° C. After the mixture was homogeneously mixed, 0.07 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and the mixture was reacted for 8 hours to obtain an acrylic copolymer (weight average molecular weight: about 146 Only).

The acrylic copolymers contained in the pressure-sensitive adhesive compositions of Examples 2 to 7 and Comparative Examples 1 to 4 were prepared in the same manner as in Example 1 except that components and compositions were changed according to the following Table 1.

(2) Production of pressure-sensitive adhesive composition

An acrylic copolymer, a crosslinking agent, a silane coupling agent, an antistatic agent and the like were mixed with the composition shown in the following Table 1 and diluted to a concentration of 28% by weight to prepare the pressure-sensitive adhesive compositions of Examples and Comparative Examples.

(4) Production of Polarizer

A protective film having a thickness of 165 mu m was adhered to a polyvinyl alcohol polarizer having a thickness of 20 mu m, the pressure-sensitive adhesive composition of Example 1 was applied on the protective film to a thickness of 23 mu m, dried at 100 DEG C for 1 minute, Layer was formed to prepare the polarizing plate of Example 1. The prepared polarizing plate was stored at 23 DEG C and 60% RH for a curing period (7 days).

The polarizing plates of the remaining examples and comparative examples were produced in the same manner as in Example 1, and were produced in the thickness and composition shown in Table 1 below.

(5) The adhesive layer  Measurement of push distance

The polarizing plates of Examples and Comparative Examples were attached to a glass plate having an adhesion area of 1.0 cm 1.0 cm and stored in an atmosphere of 23 ° C and 60% RH for 24 hours. When the force of 1.0 kgf was applied at 23 캜 and 85 캜 for 1000 seconds after storage, the pushing distance of the adhesive layer was measured with a texture analyzer (stable micro system, model: TA-XT plus) Respectively.

Example Comparative Example One 2 3 4 5 6 7 One 2 3 4 Acrylic copolymer
(Parts by weight) BA 76.5 77.4 67.5 77 76.5 77.2 76.9 77.5 77.5 76.79 62.1 MA 20 20 20 20 20 20 20 20 20 20 20 2HEA 2 2 2 2 2 2 2 2 2 2 2 CAEM One 0.1 10 One One 0.3 0.6 - - 0.01 15 AA 0.5 0.5 0.5 - 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Gross weight 100 100 100 100 100 100 100 100 100 100 100 Weight average molecular weight 146 million 135 million 155 million 149 million 1.4 million 137 million 123 million 136 million 148 million 137 million 123 million Crosslinking agent (parts by weight) 0.3 0.3 0.3 0.3 0.3 0.2 0.2 0.3 0.3 0.2 0.2 Silane coupling agent
(Parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Antistatic agent
(Parts by weight) 2 2 2 2 2 2 2 2 2 2 2 Adhesive layer thickness
(탆) 20 20 20 20 10 20 20 20 20 20 20 Polarizer thickness
(탆) 23 23 23 23 23 13 13 23 23 23 23 Pushing distance (탆) 23 ℃ 78.8 55.9 125.9 80.4 33.9 58.9 51.7 109.4 33.9 58.9 51.7 85 ℃ 56.9 47.7 46.9 48.8 13.2 72.6 67.7 98.8 35.4 72.6 67.7 ≪ EMI ID = 1.20 1.02 2.33 1.43 1.11 1.25 1.17 0.96 0.83 0.71 0.66 BA: n-butyl acrylate
MA: methyl acrylate
2HEA: 2-hydroxyethyl acrylate
CAEM: cyanoacetoxyethyl methacrylate (see Formula 1-1)
AA: Acrylic acid
Crosslinking agent: Tolylene diisocyanate-trimethylolpropane adduct
Silane coupling agent: 3-glycidoxypropyltrimethoxysilane
Antistatic agent: Potassium bisphosphorosulfonylimide

Experimental Example

(1) Durability (heat resistance, Wet heat )

The polarizing plate on which the pressure-sensitive adhesive layers of Examples and Comparative Examples were formed was cut into a size of 90 mm x 170 mm and adhered to both sides of a glass substrate (110 mm x 190 mm x 0.7 mm) so that the optical absorption axes perpendicular to each other. At this time, the applied pressure was 5 kg / cm < 2 >, and the clean room operation was performed so that bubbles or foreign matter would not occur. The heat resistance characteristics were evaluated by observing the occurrence of bubbles or peeling after being left at a temperature of 80 ° C. for 1000 hours. The moisture resistance characteristics were evaluated by observing the occurrence of bubbles or peeling after being left at a temperature of 60 ° C. and 90% RH for 1000 hours Respectively. At this time, the sample was allowed to stand at room temperature for 24 hours immediately before evaluating the state of the specimen.

<Evaluation Criteria>

Ⓞ: No bubbles or peeling.

○: Bubbles or peeling <5

?: 5 pieces? Bubbles or peeling <10 pieces

X: 10 pieces &lt; bubble &

(2) Conductivity evaluation

Polarizer sheet resistances of Examples and Comparative Examples were measured by a 4 point-probe method using a resistance meter (Mitsubishi Chemical Corporation, Loresta-GP, MCP-T610) and the results are shown in Table 2 below.

Example Comparative Example One 2 3 4 5 6 7 One 2 3 4 conductivity
(Ω / □) 5.20E + 10 3.30E + 10 4.90E + 10 7.70E + 10 3.20E + 10 4.90E + 10 4.90E + 10 6.80E + 10 4.20E + 10 4.90E + 10 4.90E + 10 Heat resistance
(85 DEG C) ◎ ○ ○ ○ ◎ ○ ○ X X X X Wet heat
(60 DEG C, 90%) ◎ ○ ○ ◎ ◎ ○ ○ X X △ △

Referring to Table 2, the polarizer of Examples satisfying Equation (1) was evaluated to be excellent in heat and moisture resistance even in a high temperature and high humidity environment without deteriorating conductivity.

10: Polarizer 20: Adhesive layer
30: Protective film

Claims (12)

A polarizer; And
And an adhesive layer laminated on at least one surface of the polarizer,
A polarizing plate satisfying the following formula (1): &lt; EMI ID =
(A / B) X (C / D) &gt; 1.0
(Where A is the thickness of the adhesive layer, B is the thickness of the polarizer, C is the adhesive layer is attached to a glass plate having an adhesion area of 1.0 cm &lt; And D is the distance that the adhesive layer is pushed when the adhesive layer is attached to a glass plate having an adhesive area of 1.0 cm X 1.0 cm and a load of 1 kgf is applied at 85 ° C for 1000 seconds.
The polarizing plate according to claim 1, further comprising a protective film laminated on at least one side of the polarizer,
Wherein the adhesive layer is laminated on the opposite surface of the protective film to which the polarizer is adhered.
The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive composition comprising an acrylic copolymer and an isocyanate-based crosslinking agent polymerized with a compound represented by the following formula (1)
[Chemical Formula 1]

(Wherein R ₁ is hydrogen or an alkyl group having 1 to 3 carbon atoms, R ₂ is an alkylene group having 1 to 20 carbon atoms, and R ₃ is

,

,

or

, R &lt; ₄ &gt; is hydrogen,

,

or

And X is

or

Y is a single bond, a methylene group,

,

or

, R ₅ is an aryl group having 6 to 20 carbon atoms or an arylalkyl group having 7 to 12 carbon atoms and R ₆ , R ₇ or R ₈ are each independently hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms , An aryl group having 6 to 20 carbon atoms or an arylalkyl group having 7 to 12 carbon atoms, and * is a bonding site).
[4] The polarizer according to claim 3, wherein the acrylic copolymer is polymerized in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer.
[4] The polarizer according to claim 3, wherein the acrylic copolymer further comprises a carboxyl group-containing (meth) acrylate monomer.
[7] The composition of claim 5, wherein the carboxyl group-containing (meth) acrylate monomer is at least one selected from the group consisting of (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylsuccinic acid, Caprolactone mono (meth) acrylate, or 2- (meth) acryloyloxyethyl tetrahydrophthalic acid.
[7] The polarizer according to claim 5, wherein the acrylic copolymer is polymerized by incorporating not more than 5 parts by weight of the carboxyl group-containing (meth) acrylate monomer based on 100 parts by weight of the acrylic copolymer.
[4] The polarizer according to claim 3, wherein the acrylic copolymer further comprises a crosslinkable monomer.
The polarizer according to claim 8, wherein the crosslinkable monomer is at least one selected from the group consisting of a monomer having a hydroxy group or a monomer having an amide group.
[10] The polarizer according to claim 8, wherein the acrylic copolymer is polymerized with 1 to 8 parts by weight of the crosslinkable monomer based on 100 parts by weight of the acrylic copolymer.
4. The polarizer of claim 3, wherein the pressure-sensitive adhesive composition further comprises an ionic antistatic agent.
An image display device comprising the polarizing plate according to any one of claims 1 to 11.

Images