KR20130023182A - Polarizer - Google Patents

Abstract

PURPOSE: A polarizing plate is provided to be lightweight, thin, and has superior physical properties such as durability, water-resistance, workability, adhesion, light-leakage-preventing properties, and the like. CONSTITUTION: A polarizing plate comprises a polarizer(11) and an adhesive layer(21). The adhesive layer is formed on at least one surface of the polarizer includes, a decomposed thermal initiator, and has a tensile modulus of 10 to 1,000 MPa at room temperature. The polarizer does not have a protective film on at least one surface. The adhesive layer is directly attached to the surface of the polarizer to which the protective film is not attached.

Description

Polarizer

The present invention relates to a polarizing plate, a manufacturing method of a polarizing plate, and a liquid crystal display device.

Liquid crystal displays (hereinafter referred to as "LCDs") are display devices utilized in various fields. LCD, liquid crystal panel; And polarizing plates attached to both sides of the liquid crystal panel.

As shown in FIG. 1, the polarizing plate 1 includes a polarizer 11; It is common to include the protective films 12a and 12b adhering to both surfaces of the said polarizer 11. In addition, the polarizing plate 1 is formed under the protective film 12b, and includes an adhesive layer 13 used to adhere to the liquid crystal panel, and the release film 14 formed under the adhesive layer 13. It may further include. In addition, although not shown in the drawings, the polarizing plate may include an additional functional film such as an antireflection film or a retardation film.

An object of this invention is to provide a polarizing plate, the manufacturing method of a polarizing plate, and LCD.

Exemplary polarizing plates of the present invention include a polarizer; And an adhesive layer attached to at least one surface of the polarizer. The pressure-sensitive adhesive layer may include a thermal initiator having a half-life temperature of 50 ° C. to 80 ° C. in a decomposed state, and an elastic modulus of 10 MPa to 1,000 MPa.

As used herein, the term elastic modulus may be a storage modulus or a tensile modulus, and preferably may be a tensile modulus. In addition, the elastic modulus may be an elastic modulus measured at room temperature. As used herein, the term room temperature refers to a naturally occurring temperature that is not heated or reduced, for example, 10 ° C. to 40 ° C., 20 ° C. to 30 ° C., about 20 ° C., about 23 ° C., about 25 ° C., or about 30 ° C. It may mean.

The kind of polarizer contained in a polarizing plate is not specifically limited, The normal polarizer known in this field can be used. The polarizer is a functional film or sheet capable of extracting only light vibrating in one direction from incident light while vibrating in various directions.

In one example, in the polarizer, attachment of at least one protective film may be omitted from the protective films that are typically attached to both surfaces thereof. That is, the polarizer may be a polarizer having no protective film attached to at least one surface thereof, and the pressure-sensitive adhesive layer may be directly attached to a surface to which the protective film of the polarizer is not attached. In the present specification, the term "B directly attached to A" means a case where A and B are attached in a state where no other layer or element exists between A and B.

2 is a cross-sectional view illustrating the polarizing plate 2 by way of example. As shown in FIG. 2, the polarizing plate 2 includes a polarizer 11; And an adhesive layer 21. In the example of FIG. 2, a protective film may be attached to a surface on which the pressure-sensitive adhesive layer 21 of the polarizer 11 is not formed, but is not necessarily attached to the protective film. In addition, a protective film may exist between the polarizer 11 and the pressure-sensitive adhesive layer 21 of FIG. 2 as necessary.

As a polarizer, a polyvinyl alcohol polarizer etc. can be used, for example. Such a polarizer may be, for example, a form in which a dichroic dye is adsorbed in a polyvinyl alcohol-based resin film. Polyvinyl alcohol-type resin which comprises a polarizer can be obtained by gelatinizing polyvinylacetate-type resin, for example. As polyvinyl acetate type resin, Homopolymer of vinyl acetate; And copolymers of vinyl acetate and other monomers, and the like. Examples of the monomer copolymerizable with vinyl acetate include, but are not limited to, a mixture of one or more kinds of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

Since the polarizer is usually made of a hydrophilic resin, it exhibits properties vulnerable to moisture. In addition, since the polarizer is manufactured through the stretching process, the dimensional change such as shrinkage is likely to occur under severe conditions such as high temperature or high temperature and high humidity conditions, or a severe environmental change condition, thereby deteriorating optical characteristics of the polarizing plate. There is this. In order to solve this problem, in the conventional polarizing plate 1 structure, in order to reinforce the strength of the polarizer 11 and the like, as shown in FIG. Attach to both sides of 11).

In order to thin the polarizing plate, when the protective film is not used, for example, the protective film 12b is removed from the structure shown in FIG. 1, but instead the adhesive 13 has a high modulus of elasticity. It is conceivable that the way that 13) plays the role of a protective film. However, when the elastic modulus is increased, the peeling force of the pressure-sensitive adhesive is greatly reduced, and thus the adhesion between the pressure-sensitive adhesive 13 and the polarizer 11 is inferior. Therefore, the method of simply increasing the elastic modulus of the pressure-sensitive adhesive, the water resistance, optical properties, etc. are degraded due to the weak dimensional stability.

In the polarizing plate, the pressure-sensitive adhesive layer contains a thermal initiator having a half-life temperature of 50 ° C. to 80 ° C. in a decomposed state, and thus the adhesiveness between the pressure-sensitive adhesive layer and the polarizer is sufficient while setting the elastic modulus of the pressure-sensitive adhesive layer to 10 MPa to 1,000 MPa. I can keep it. As a result, one or more protective films may be removed from the polarizing plate, thereby making the polarizing plate thinner and lighter, and also maintaining excellent physical properties such as durability, workability, and optical properties. In this specification, as described above, the polarizing plate without the protective film may be referred to as a thin polarizer.

In the polarizing plate, the pressure-sensitive adhesive layer contains a thermal initiator having a half-life temperature of 50 ° C. to 80 ° C. in a decomposed state for 10 hours. The term "thermal initiator in a decomposed state" refers to, for example, after the thermal initiator generates a radical or the like by thermal treatment described later to induce polymerization and / or crosslinking reaction of the polyfunctional acrylate present in the pressure-sensitive adhesive layer. It can mean a state. The minimum with preferable elasticity modulus at normal temperature of an adhesive layer is 30 MPa, More preferably, it is 40 MPa, More preferably, it is 60 MPa, More preferably, it is 80 MPa, More preferably, it is 100 MPa, More preferably, May be 150 MPa, more preferably 200 MPa, even more preferably 250 MPa. On the other hand, the upper limit of the elastic modulus is preferably, for example, 900 MPa, more preferably 800 MPa, more preferably 700 MPa, even more preferably about 600 MPa. Within such a range of elastic modulus, it is possible to effectively suppress the dimensional change of the polarizer under severe conditions. In the present specification, the elastic modulus of the pressure-sensitive adhesive layer is a numerical value measured in the manner described in Examples described later.

It is preferable that an adhesive layer also satisfy | fills the conditions of following General formula (1).

[Formula 1]

D = M ₂ -M ₁ > 9 MPa

In General Formula 1, M ₁ is an elasticity modulus at normal temperature measured after forming the layer of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition on one surface of the polarizer, and M ₂ is a layer of the pressure-sensitive adhesive layer or pressure-sensitive adhesive composition attached to the polarizer. Elastic modulus at room temperature measured after heat treatment for 10 minutes at a temperature of 80 ℃.

In Formula 1, D is preferably at least 10 MPa, more preferably at least 20 MPa, even more preferably at least 40 MPa, more preferably at least 45 MPa, even more preferably at least 50 MPa, more preferably Is at least 100 MPa, more preferably at least 200 MPa, more preferably at least 300 MPa, even more preferably at least 350 MPa, more preferably at least 400 MPa, even more preferably at least 450 MPa, more preferably 500 It may be at least MPa. By satisfying the conditions of the general formula 1, even when the pressure-sensitive adhesive layer is directly attached to the polarizer, for example, the adhesiveness to the polarizer is maintained at a high level, the dimensional change of the polarizer is effectively suppressed, and the durability of the polarizing plate, Workability, water resistance and optical properties can be maintained excellent. In Formula 1, the upper limit of D is preferably 1,500 MPa, more preferably 1,000 MPa, even more preferably 900 MPa, more preferably 800 MPa, even more preferably 700 MPa, more preferably 600 MPa. .

The method for forming the pressure-sensitive adhesive layer is not particularly limited, and can be formed by, for example, curing a conventional room temperature curing type, moisture curing type, heat curing type or active energy ray curing type pressure-sensitive adhesive composition. Hardening of an adhesive composition in the above means the state which expressed the adhesive characteristic in the adhesive composition by the physical or chemical reaction or action of the component contained in an adhesive composition. In addition, room temperature, moisture, heat or active energy ray-curable type means a pressure-sensitive adhesive composition of the type wherein the curing is induced at room temperature, induced by the application of moisture or heat, or induced by irradiation of active energy rays. In addition, the category of "active energy rays" includes microwaves, infrared rays (IR), ultraviolet rays (UV), X-rays and gamma rays, as well as alpha-particle beams and proton beams. , Particle beams such as neutron beams and electron beams, and the like, and typically may be ultraviolet rays or electron beams.

In one example, the pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer containing a cured product of a thermosetting or active energy ray-curable pressure-sensitive adhesive composition.

One exemplary pressure-sensitive adhesive layer may include an interpenetrating polymer network (hereinafter sometimes referred to as "IPN"). The term "IPN structure" may refer to a state in which at least two or more kinds of crosslinked structures exist in the pressure-sensitive adhesive layer, and in one example, the crosslinked structures may be entangled with each other, or linked or infiltrated with each other. It can be in a penetrating state. IPN of an adhesive layer can contain the crosslinked structure of a thermosetting component, and the crosslinked structure of a radically polymerizable component, for example. In one example, the thermosetting component may comprise a crosslinkable acrylic polymer and a multifunctional crosslinking agent, and the radically polymerizable component may be a multifunctional acrylate. In the above, the crosslinking reaction of the radical polymerizable component may proceed by irradiation of active energy rays and / or application of heat. In the structure of the pressure-sensitive adhesive layer, a polarizing plate having excellent durability under harsh conditions and excellent in workability, optical characteristics, and light leakage suppression ability can be realized.

As the acrylic polymer, for example, an acrylic polymer having a weight average molecular weight (M _w ) of 300,000 or more, 400,000 or more, or 500,000 or more can be used. In the present specification, the weight average molecular weight is a conversion value with respect to standard polystyrene measured by Gel Permeation Chromatograph (GPC). In addition, in this specification, unless otherwise specified, the term "molecular weight" means a "weight average molecular weight." If the molecular weight of a polymer is 300,000 or more, the adhesive layer which has the outstanding durability under severe conditions can be formed. The upper limit of the molecular weight of the polymer is not particularly limited, and can be adjusted in the range of 3 million or less, 2.5 million or less, or 2 million or less, for example, in consideration of durability of the pressure-sensitive adhesive and coating property of the composition.

In one example, the acrylic polymer may be a polymer including a (meth) acrylic acid ester monomer and a crosslinkable monomer as a polymer unit, and preferably 50 parts by weight to 99.9 parts by weight of a (meth) acrylic acid ester monomer and a crosslinkable monomer. It may be a polymer including 0.1 parts by weight to 50 parts by weight in a polymerized form. As used herein, the term "crosslinkable monomer" refers to a monomer that can be copolymerized with the monomer forming the polymer and that can provide a crosslinkable functional group in the side chain or terminal of the polymer after copolymerization. In addition, in this specification, unless otherwise specified, a unit "weight part" means the ratio of weight. By adjusting the weight ratio of the monomer contained in the polymer as described above, it is possible to provide a pressure-sensitive adhesive excellent in the initial adhesive strength or durability.

As the (meth) acrylic acid ester monomer, for example, alkyl (meth) acrylate can be used, and alkyl (meth) acryl having an alkyl group having 1 to 14 carbon atoms in consideration of the cohesive force, glass transition temperature or tackiness of the pressure sensitive adhesive Rate can be used. Examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth ) Acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-octyl (meth) acrylate, iso Octyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and tetradecyl (meth) acrylate, and one or more of the above can be used.

The crosslinkable monomer may include a copolymerizable functional group and a crosslinkable functional group which can be copolymerized with other monomers at the same time. As a crosslinkable functional group, nitrogen containing functional groups, such as a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, or an amino group, etc. can be illustrated. Various monomers are known in the art which play such a role, and all of these monomers can be used. As a crosslinkable monomer, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Hydroxy group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate; (Meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyl acid, acrylic acid duplex, itaconic acid, maleic acid and Carboxyl group-containing monomers such as maleic anhydride or nitrogen-containing monomers such as (meth) acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam, and the like can be exemplified, and one or more of the above can be used. However, it is not limited thereto.

The acrylic polymer may further include various comonomers in a polymerized form, if necessary.

For example, the acrylic polymer may further include a monomer represented by Formula 1 in a polymerized form. Such monomers may be added for the purpose of controlling the glass transition temperature and imparting other functionality.

[Formula 1]

Wherein each of R ₁ to R ₃ independently represents hydrogen or alkyl, R ₄ is cyano; Phenyl unsubstituted or substituted with alkyl; Acetyloxy; Or COR < _{5 &} gt ;, wherein R < ₅ > represents amino or glycidyloxy substituted or unsubstituted with alkyl or alkoxyalkyl.

In the definition of R ₁ to R _{5 in} the above formula, alkyl or alkoxy means alkyl or alkoxy having 1 to 8 carbon atoms, preferably methyl, ethyl, methoxy, ethoxy, propoxy or butoxy.

The monomer of Chemical Formula 1 may be included in an amount of 20 parts by weight or less based on the weight of the (meth) acrylic acid ester monomer or the crosslinkable monomer, but this may be changed according to the purpose.

The acrylic polymer can be prepared by applying a mixture of monomers containing the above-mentioned components to conventional polymerization methods such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization or emulsion polymerization. .

As a multifunctional crosslinking agent which crosslinks the above acrylic polymer in an adhesive layer, general crosslinking agents, such as an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent, can be used, for example, The use of an isocyanate crosslinking agent is preferable. It may be, but is not limited thereto. As an isocyanate crosslinking agent, polyfunctional isocyanate compounds, such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethyl xylene diisocyanate, or naphthalene diisocyanate, or the said polyfunctional Compounds obtained by reacting an isocyanate compound with a polyol compound such as trimethylol propane and the like can be cited. Examples of the epoxy crosslinking agent include ethylene glycol diglycidyl ether, triglycidyl ether, and trimethylolpropane triglycidyl ether, N, N, N. And one or more selected from the group consisting of ', N'-tetraglycidyl ethylenediamine and glycerin diglycidyl ether, and the aziridine crosslinking agent is N, N'-toluene-2,4-bis (1- Aziridinecarboxamide), N, N'-diphenylmethane-4,4'- One or more selected from the group consisting of s (1-aziridinecarboxamide), triethylene melamine, bisisoprotaloyl-1- (2-methylaziridine) and tri-1-aziridinylphosphineoxide May be, but is not limited thereto. Further, the metal chelate crosslinking agent may include a compound in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and / or vanadium is coordinated with acetyl acetone, ethyl acetoacetate, or the like, but is not limited thereto. It doesn't happen.

For example, the multifunctional crosslinking agent may be included in an amount of 0.01 to 10 parts by weight, more preferably 0.01 to 5 parts by weight based on 100 parts by weight of the acrylic polymer in the above-described pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition for implementing the pressure-sensitive adhesive layer. It may be. In this range, the cohesive force and durability of the pressure-sensitive adhesive can be excellent.

The pressure-sensitive adhesive layer of the IPN structure may include a crosslinked structure formed by crosslinking polymerization of a multifunctional radical polymerizable compound together with a crosslinked structure including an acrylic polymer crosslinked by the multifunctional crosslinking agent.

As used herein, the term "multifunctional radically polymerizable compound" refers to two functional groups that can be crosslinked and / or polymerized by reaction with radicals generated by radical initiators such as thermal initiators or photoinitiators, that is, two radically polymerizable functional groups. It can mean the compound containing the above. As an example of a radically polymerizable functional group, an acryloyl group or a methacryloyl group etc. can be illustrated.

Examples of the polyfunctional radically polymerizable compound include polyfunctional acrylates. A polyfunctional acrylate is a compound which has 2 or more acryloyl group or methacryloyl group in a molecule | numerator. For example, 1, 4- butanediol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethyleneglycol di (meth) acrylate, neopentyl Neopentylglycol adipate di (meth) acrylate, hydroxyl puivalic acid neopentylglycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dish Clopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (meth) acryloxy ethyl isocyanurate, allylated cyclohexyl di (meth) acrylate, tricyclodecane Dimethanol (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) acrylate, tricyclodecane dimethanol (meth) acrylate Neopentyl glycol modified trimethylpropane di (meth) acrylate, adamantane di (meth) acrylate or 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene difunctional acrylates such as (fluorine) and the like; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethyl isocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; 5-functional acrylates, such as propionic acid modified dipentaerythritol penta (meth) acrylate; And dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (ex. Isocyanate monomers and trimethylolpropane tri (meth) acrylate Six-functional acrylates such as reactants and the like can be used, and in some cases, known as photocurable oligomers in this field, various urethane acrylates, polycarbonate acrylates, polyester acrylates, polyether acrylates Or an epoxy acrylate, etc. The polyfunctional acrylate may be used in one kind or a mixture of two or more kinds, and it is preferable to use an acrylate having a molecular weight of less than 1,000 and trifunctional or more than one in terms of durability. It doesn't happen.

As a polyfunctional acrylate, it is preferable to use what contains a ring structure among frame | skeletal structures. By using such an acrylate, the shrinkage or expansion of a polarizer can be suppressed more effectively, and the light leakage suppression effect can also be improved. Ring structures included in the polyfunctional acrylate include carbocyclic structures or heterocyclic structures; Or any of a monocyclic or polycyclic structure. Examples of the polyfunctional acrylate including a ring structure include monomers having isocyanurate structures such as tris (meth) acryloxy ethyl isocyanurate and isocyanate-modified urethane (meth) acrylates (ex. Isocyanate monomers and trimethyl) 6 functional acrylates, such as a reactant of rolled propane tri (meth) acrylate, etc., etc. are mentioned, but it is not limited to this.

In the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer, the multifunctional radical polymerizable compound may be included in an amount of 5 parts by weight to 150 parts by weight with respect to 100 parts by weight of the acrylic polymer, thereby more effectively controlling the elastic modulus of the pressure-sensitive adhesive layer. In addition, durability can be excellently maintained.

The pressure-sensitive adhesive layer may further include a silane coupling agent. The silane coupling agent improves the adhesiveness and adhesion stability of the pressure-sensitive adhesive to improve heat resistance and moisture resistance, and also improves adhesion reliability even when the pressure-sensitive adhesive is left for a long time under severe conditions. As the silane coupling agent, for example, gamma-glycidoxypropyl triethoxy silane, gamma-glycidoxypropyl trimethoxy silane, gamma-glycidoxypropyl methyldiethoxy Silane, gamma-glycidoxypropyl triethoxy silane, 3-mercaptopropyl trimethoxy silane, vinyltrimethoxysilane, vinyltriethoxy silane, gamma-methacryloxypropyl trimethoxy Silane, gamma-methacryloxy propyl triethoxy silane, gamma-aminopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane, 3-isocyanato propyl triethoxy Silane, gamma-acetoacetatepropyl trimethoxysilane, gamma-acetoacetatepropyl triethoxy silane, beta-cyanoacetyl trimethoxy silane, beta-cyanoacetyl tri Ethoxy silane, acetoxyaceto trimethoxy And the like is available, can be used to mix one kinds or more kinds of the above. In the present invention, it is preferable to use a silane coupling agent having an acetoacetate group or a beta (beta) -cyanoacetyl group, but is not limited thereto. In the pressure-sensitive adhesive layer, the silane coupling agent may be included in an amount of 0.01 parts by weight to 5 parts by weight, preferably 0.01 parts by weight to 1 parts by weight, based on 100 parts by weight of the acrylic polymer, thereby effectively maintaining adhesion and durability.

The pressure-sensitive adhesive layer may further include a tackifier. As a tackifier, a hydrocarbon resin or its hydrogenated substance, rosin resin or its hydrogenated substance, rosin ester resin or its hydrogenated substance, terpene resin or its hydrogenated substance, terpene phenol resin or its hydrogenated substance, polymeric rosin resin Or a mixture of one or more kinds of polymerized rosin ester resins and the like can be used. The tackifier may be included in an amount of 1 part by weight to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer.

The pressure-sensitive adhesive layer may further include at least one additive selected from the group consisting of an epoxy resin, a curing agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, and a plasticizer within a range that does not affect the desired effect. It may further comprise.

The kind of thermal initiator contained in the pressure-sensitive adhesive layer in the decomposed state or included in the pressure-sensitive adhesive composition is not particularly limited, and if the 10-hour half-life temperature is in the range of 50 ° C to 80 ° C, the use of a known thermal initiator may be used. It is possible. The 10-hour half-life temperature is adjusted to 50 ° C. to 80 ° C. to prevent degradation of the thermal initiator in the process of forming the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition described later, and the elastic modulus is efficiently increased in the heat treatment process to increase the elastic modulus. You can do that. As the thermal initiator, for example, 2,2-azobis-2,4-dimethylvaleronitrile (V-65, Wako), 2,2-azobisisobutyronitrile (V-60, Azo initiators such as Wako (manufactured) or 2,2-azobis-2-methylbutyronitrile (V-59, made by Wako); Dipropyl peroxydicarbonate (Peroyl NPP, NOF (manufactured)), Diisopropyl peroxy dicarbonate (Peroyl IPP, NOF (manufactured)), Bis-4-butylcyclohexyl peroxy dicarbonate (Peroyl TCP, NOF (manufactured) )), Diethoxyethyl peroxy dicarbonate (Peroyl EEP, NOF (product)), diethoxyhexyl peroxy dicarbonate (Peroyl OPP, NOF agent), hexyl peroxy dicarbonate (Perhexyl ND, NOF agent) ), Dimethoxybutyl peroxy dicarbonate (Peroyl MBP, NOF (product)), bis (3-methoxy-3-methoxybutyl) peroxy dicarbonate (Peroyl SOP, NOF agent), hexyl peroxy pival Rate (Perhexyl PV, NOF), amyl peroxy pivalate (Luperox 546M75, Atofina), butyl peroxy pivalate (Perbutyl, NOF) or trimethylhexanoyl peroxide (Peroyl 355, NOF) Peroxy ester compounds such as (agent); Dimethyl hydroxybutyl peroxane neodecanoate (Luperox 610M75, Atofina), amyl peroxy neodecanoate (Luperox 546M75, Atofina) or butyl peroxy neodecanoate (Luperox 10M75, Atofina) Peroxy dicarbonate compounds such as; Acyl peroxides such as 3,5,5-trimethylhexanoyl peroxide, lauryl peroxide, benzoyl peroxide or dibenzoyl peroxide; Ketone peroxide; Dialkyl peroxides; Peroxy ketal; Or a mixture of one or more kinds of peroxide initiators such as hydroperoxide and the like. It is preferable to use acyl peroxide as a thermal initiator, but is not limited thereto.

The thermal initiator may be included in the pressure sensitive adhesive layer or the pressure sensitive adhesive composition in an amount of 0.01 parts by weight to 10 parts by weight based on 100 parts by weight of the acrylic polymer. When the content of the thermal initiator is 0.01 parts by weight or more, the elastic modulus of the pressure-sensitive adhesive layer can be sufficiently increased by heat treatment, and a sufficient gel content can be expressed. When the content of the thermal initiator is 10 parts by weight or less, the thermal initiator that does not decompose in the adhesive layer remains, and it is possible to prevent a change in the adhesive force over time.

The pressure-sensitive adhesive layer may have a thickness of 5 μm to 50 μm. The thickness of the pressure-sensitive adhesive layer is adjusted to 5 µm or more and 50 µm or less to effectively prevent shrinkage or expansion of the polarizer.

The polarizing plate is formed under the pressure-sensitive adhesive layer containing the decomposed thermal initiator, and may further include a second pressure-sensitive adhesive layer used to attach the polarizing plate to the liquid crystal panel. Hereinafter, for convenience of explanation, the pressure-sensitive adhesive layer attached to the polarizer described above may be referred to as a first pressure-sensitive adhesive layer.

The second adhesive layer may have an elastic modulus at 25 ° C. of 0.01 MPa to 1.0 MPa, preferably 0.02 MPa to 0.8 MPa, and more preferably 0.03 MPa to 0.7 MPa. In such a range, the pressure-sensitive adhesive layer can effectively suppress the shrinkage or expansion of the polarizer under severe conditions, and at the same time can exhibit excellent wettability with respect to adherends such as glass substrates.

The second pressure sensitive adhesive layer can be formed using any suitable type from the above-described thermosetting type, room temperature curing type, moisture curing type, or active energy ray-curable pressure-sensitive adhesive composition, so long as it exhibits the elastic modulus in the above-described range, It may be formed using the same or different types as the first pressure-sensitive adhesive layer.

The second adhesive layer may have a thickness of 5 μm to 50 μm. The thickness of a 2nd adhesive layer is adjusted to 5 micrometers or more and to 50 micrometers or less, and the wettability of an adhesive layer and the durability of a polarizing plate can be effectively maintained.

When the first and second pressure-sensitive adhesive layers are formed in the polarizing plate, the total thickness can be, for example, in the range of about 10 μm to 80 μm, preferably 20 μm to 60 μm, more preferably 30 μm to 60 μm. have. By adjusting the overall thickness of the pressure-sensitive adhesive layer as described above, it is possible to provide a polarizing plate having a thin thickness and excellent in physical properties such as durability under severe conditions.

The polarizing plate may further include a protective film which is present only on one or both surfaces of the polarizer, preferably on the surface where the first pressure-sensitive adhesive layer is not attached to the polarizer. As a protective film, For example, Cellulose-type films, such as a TAC film; Polyester film such as PET (poly (ethylene terephthalate)) film and the like; Polycarbonate film; Polyethersulfone-based films; Polyolefin films such as an acrylic film and / or a polyethylene film, a polypropylene film, a polyolefin film having a cyclo-based or norbornene structure, or an ethylene-propylene copolymer film may be used, but is not limited thereto. The protective film may be attached to the polarizer through, for example, the adhesive layer described above.

The polarizing plate may further include a release film attached to the lower portion of the pressure-sensitive adhesive layer. As a release film, the conventional structure of this field can be employ | adopted. The polarizing plate may further include one or more functional layers selected from the group consisting of an antireflection layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film, as necessary.

An exemplary method for producing a polarizing plate of the present invention includes a thermal initiator in an undecomposed state having a half-life temperature of 50 ° C. to 80 ° C. on one surface of a polarizer, and an adhesive layer or pressure-sensitive adhesive having an elastic modulus at 25 ° C. of 1 MPa or less. Forming a layer of the composition; And heat treating the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition to increase the elastic modulus at room temperature of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition to 10 MPa to 1,000 MPa.

The method may be, for example, a method of manufacturing the aforementioned polarizing plate. Accordingly, in one example, the surface of the polarizer in which the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition is formed may be a surface to which a protective film is not attached.

The method of forming the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition on one surface of the polarizer in the above step is not particularly limited.

In one example, when it is desired to form the above-described IPN in the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition includes (1) an acrylic polymer, a polyfunctional crosslinking agent, a polyfunctional radical polymerizable compound and a 10 hour half-life temperature May be formed by coating a coating liquid comprising a pressure-sensitive adhesive composition comprising a thermal initiator having a temperature of 50 ° C to 80 ° C, and optionally, after the coating step, (2) curing or semi-curing the coating layer. It can also be done.

The specific component contained in the adhesive composition used by the said method, its component ratio, etc. are as having already described in the item of the 1st adhesive layer. However, the pressure-sensitive adhesive composition may further include a photoinitiator in consideration of the efficiency of the curing process by irradiation of electromagnetic waves, which will be described later, in addition to the above components. As a photoinitiator, as long as it can generate | occur | produce a radical by irradiation of an active energy ray and can start a radical reaction, it can be used without a restriction | limiting in particular. As a photoinitiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylanino acetophenone, 2 , 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1one, 1-hydroxycyclohexylphenylketone , 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) Ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthra Quinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chloro thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p -Dimethylamino benzoate Ter, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like can be used. .

The photoinitiator may be included in an amount of 0.2 to 20 parts by weight, preferably 0.2 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the acrylic polymer. The photoinitiator, for example, may be included in an amount of 0.2 to 20 parts by weight based on 100 parts by weight of the multifunctional radically polymerizable compound. Through such control, the reaction of the multifunctional radically polymerizable compound can be effectively induced, and the adhesive properties can be prevented from deteriorating due to the remaining components after curing.

In addition, the coating of the pressure-sensitive adhesive composition may be performed by a means such as a bar coater or a comma coater, and the composition or the coating liquid containing the same may be applied onto the polarizer or a suitable process substrate.

Curing or semi-curing the coating layer may be a step of ripening the coating layer at an appropriate temperature and / or irradiating an active energy ray. By the above aging process, for example, the crosslinking reaction of the acrylic polymer and the multifunctional crosslinking agent can be induced. In addition, the crosslinking polymerization reaction of the polyfunctional radically polymerizable compound may be induced by, for example, irradiation of the active energy ray. When the aging and the irradiation of the electromagnetic wave proceeds at the same time, it may be performed sequentially in any order, or may be performed simultaneously. In addition, in this step, the crosslinking reaction or the polymerization reaction may be completed to cure the coating layer, but in consideration of the heat treatment process described below, it is preferable to induce a semi-curing by inducing only a part of the crosslinking and / or polymerization reaction. The degree of semi-curing can be determined in consideration of, for example, the process efficiency of forming the pressure-sensitive adhesive layer on the polarizer or the degree of increase in the elastic modulus during heat treatment described later.

The conditions for advancing the crosslinking reaction of the acrylic polymer and the polyfunctional crosslinking agent are not particularly limited, and the average skilled in the art can set the above conditions appropriately in consideration of the range of the desired gel fraction and the like. However, in the step of inducing the crosslinking reaction, it is preferable that the thermal initiator included in the composition is decomposed and controlled so that the crosslinking or polymerization reaction by the thermal initiator does not proceed. In addition, the conditions of the step of irradiating an active energy ray, for example, ultraviolet rays, to enable the polymerization of the radically polymerizable compound are not particularly limited, for example, a high pressure mercury lamp, an electrodeless lamp or a xenon lamp. Can be performed using a means such as In addition, the irradiation conditions are not particularly limited so long as they are controlled so that polymerization of the radically polymerizable compound can be appropriately performed without compromising overall physical properties, for example, the roughness is 50 mW / cm ² to 2,000 mW / cm ² . Control, and the amount of light can be controlled from 10 mJ / cm ² to 1,000 mJ / cm ² , and irradiated for a suitable time.

Subsequently, the pressure-sensitive adhesive layer is heat-treated to increase the elastic modulus at room temperature to 10 MPa to 1,000 MPa. For example, the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition may be performed by maintaining at 40 ° C to 120 ° C, 60 ° C to 100 ° C, 70 ° C to 90 ° C, or about 80 ° C. In addition, the heat treatment may be performed, for example, for 1 minute to 30 minutes, 5 minutes to 30 minutes, 5 minutes to 20 minutes, 5 minutes to 15 minutes, or about 10 minutes. Through this process, the thermal initiator contained in the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition is decomposed to induce crosslinking polymerization reaction of the polyfunctional radically polymerizable compound, etc., and as a result, the elastic modulus can be increased. In the heat treatment process, if the heat treatment temperature is too low or the treatment time is short, the synergistic effect of the elastic modulus may not be sufficient, and if the temperature is too high or the treatment time is long, the properties of other components of the polarizing plate may be damaged. In consideration of this, it can be carried out under appropriate conditions.

In the manufacturing process of the polarizing plate, the step of forming the above-mentioned second pressure-sensitive adhesive on the pressure-sensitive adhesive layer with the above-mentioned step may be further performed. The method of forming the second pressure sensitive adhesive layer is not particularly limited, and according to the pressure sensitive adhesive composition, a general method known in the art may be applied.

An exemplary LCD of the present invention may include a liquid crystal panel and the polarizing plate attached to one side or both sides of the liquid crystal panel.

Liquid crystal panels included in the LCD include, for example, passive matrix panels such as twisted nematic (TN) type, super twisted nematic (STN) type, ferroelectic (F) type, or polymer dispersed (PD) type; Active matrix panels such as two-terminal or three-terminal; Examples include an In Plane Switching (IPS) panel and a Vertical Alignment (VA) panel.

Further, other components of the LCD, for example, a light source, a substrate such as a color filter substrate or an array substrate, an alignment layer or a color filter, etc. are not particularly limited, and configurations known in the art may be employed without limitation. have.

The polarizing plate or the LCD including the same is light and thin, but has excellent physical properties such as durability, water resistance, durability, workability, adhesiveness, and optical properties.

1 is a cross-sectional view schematically showing a conventional polarizing plate.
2 and 3 are cross-sectional views showing exemplary polarizing plates of the present invention.

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

The physical properties in the following Examples and Comparative Examples were evaluated in the following manner.

1. Evaluation of Tensile Modulus

In the present specification, the tensile modulus of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition is measured or stored through a stress-strain test by tension in accordance with standard test methods specified in KS M 3006, ASTM D638, ASTM D882, ISO572 or BS2782. An elasticity modulus is measured and converted and calculated | required by the following conversion formula. Specifically, a sample having a laminated structure of a PET release film (thickness: 38 μm, MRF-38), an adhesive layer, and a PET release film (thickness: 38 μm, MRF-38), prepared in Examples or Comparative Examples. Was cut into dog bone type specimens having a length of 7 cm and a width of 1 cm. Both ends of the specimens were fixed with a tensile test jig, and the tensile modulus was measured. The measurement conditions of the tensile modulus are as follows.

<Measurement conditions of tensile modulus>

Measuring instrument: Universal Testing Machine (UTM)

Equipment Model: Zwick Roell Z010, Instron

Measuring conditions:

Load cell: 500 N

Tensile Speed: 3 mm / sec

<Measurement of storage modulus and conversion to tensile modulus>

The pressure-sensitive adhesive layer is cut to a size of 15 cm × 25 cm × 25 μm (width × length × thickness), and the cut pressure-sensitive adhesive layer is laminated in five layers. Subsequently, the laminated pressure-sensitive adhesive layer was cut into a circle having a diameter of 8 mm, and then left in the compressed state using glass to stand overnight, thereby improving the wetting at the interface between the layers, thereby resulting in bubbles generated during lamination. Prepare the sample by removing. Subsequently, the sample is placed on a parallel plate, the gap is adjusted, the zero point of Normal & Torque is set, the stabilization of the normal force is confirmed, and the following conditions are measured for the storage modulus. The tensile modulus is obtained by

Measuring instruments and measuring conditions

Measuring instrument: ARES-RDA, TA Instruments Inc. with forced convection oven

Measuring conditions:

geometry: 8 mm parallel plate

gap: around 1 mm

test type: dynamic strain frequency sweep

strain = 10.0 [%], temperature: 30 ℃

initial frequency: 0.4 rad / s, final frequency: 100 rad / s

<Conversion formula>

E = 3G

In the conversion equation, E represents a tensile modulus, and G represents a storage modulus.

2. Peel force  And Re-peelability  evaluation

The polarizing plate was cut to a size of 25 mm x 100 mm (width x length) to prepare a specimen. Subsequently, the PET release film was peeled off from the specimen, and a flat plate specimen was attached to the alkali-free glass with a laminator through the pressure-sensitive adhesive layer. It was then compressed for about 20 minutes in an autoclave (50 ° C., 0.5 atm) and stored for 25 hours at constant temperature and humidity conditions (23 ° C., 50% relative humidity). Subsequently, using a TA instrument (texture analyser, manufactured by Stable Microsystem Co., Ltd.), the peeling force was measured while the polarizing plate was peeled from the alkali free glass at a peel rate of 300 mm / min and a peel angle of 180 degrees. In addition, re-peelability was evaluated based on the following criteria.

<Releasability Evaluation Criteria>

○: 1 day after attachment, peeling force is 800 N / 25 mm or less

(Triangle | delta): Peeling force is 1,000 N / 25 mm or more after 1 day of attachment

X: Peeling force 2,000 N / 25 mm or more after 1 day of attachment

3. Endurance reliability  evaluation

Two specimens each having a polarizing plate cut to a size of 90 mm × 170 mm (width × length) were prepared for each Example and Comparative Example. Subsequently, two specimens were attached to both sides of a glass substrate (110 mm x 190 mm x 0.7 mm = width x length x thickness), but the samples were prepared by attaching the optical absorption axes to cross each other. The pressure applied at the time of attachment was about 5 Kg / cm ^2, and the operation was performed in a clean room so that bubbles or foreign substances did not occur at the interface. The heat-and-moisture resistance characteristics of the sample were observed for the occurrence of bubbles or peeling at the adhesive interface after the sample was left for 1,000 hours under conditions of a temperature of 60 ° C. and a relative humidity of 90%. In addition, the heat resistance property observed the generation of the bubble or peeling in the adhesion interface, after leaving a sample for 1,000 hours at 80 degreeC temperature conditions. The sample prepared immediately before the measurement of heat-resistant or heat-resistant reliability was left at room temperature for 24 hours, and evaluation was performed. Evaluation conditions are as follows.

Durability Reliability Evaluation Criteria

○: no bubbles and peeling

Δ: slight bubbles and / or peeling

×: large amount of bubbles and / or peeling

4. Water resistance evaluation

Samples were prepared by attaching specimens obtained by cutting the polarizing plates prepared in Examples and Comparative Examples to a size of 90 mm × 170 mm (width × length) to one side of a glass substrate (110 mm × 190 mm × 0.7 mm = width × length × thickness). . The pressure applied at the time of attachment was about 5 Kg / cm ^2, and the operation was performed in a clean room so that bubbles or foreign substances did not occur at the interface. Subsequently, the prepared sample was poured into water at a temperature of 60 ° C., left for 24 hours, and then taken out to observe whether bubbles or peeling occurred, and water resistance was evaluated based on the following criteria.

<Water resistance evaluation standard>

○: no bubbles and peeling

Δ: slight bubbles and / or peeling

×: large amount of bubbles and / or peeling

5. Light transmission  Uniformity evaluation

The polarizers prepared in Examples and Comparative Examples were attached to the 22-inch LCD monitor (manufactured by LG Philips LCD) with the optical absorption axes crossed with each other, and stored for 24 hours under constant temperature and humidity conditions (23 ° C, 50% relative humidity). And it left for 200 hours at the temperature of 80 degreeC. Then, the monitor was irradiated with light using a backlight in a dark room, and the light transmittance uniformity was evaluated based on the following criteria.

<Light transmission uniformity evaluation criteria>

(Double-circle): When the permeability of light transmittance is not judged visually in the four peripheral parts of a monitor.

(Circle): When the light transmittance nonuniformity is slightly observed by the four peripheral parts of a monitor.

(Triangle | delta): When the light transmittance nonuniformity is observed with the naked eye somewhat in the four peripheral parts of a monitor.

X: When a large amount of light-transmissive nonuniformity is observed by the naked eye in four peripheral parts of a monitor

6. Evaluation of weight average molecular weight and molecular weight distribution

The weight average molecular weight and molecular weight distribution of the acrylic polymer were measured under the following conditions using GPC. The measurement result was converted into the calibration curve using standard polystyrene of Agilent system.

<Weight average molecular weight measurement conditions>

Meter: Agilent GPC (Agilent 1200 series, USA)

Column: Connect 2 PL Mixed B

Column temperature: 40 ° C

Eluent: tetrahydrofuran

Flow rate: 1.0 mL / min

Concentration: ~ 2 mg / mL (100 μL injection)

Manufacturing example  1. Preparation of Acrylic Polymer

Nitrogen gas was refluxed, and 98 parts by weight of n-butyl acrylate (n-BA) and 2 parts by weight of 2-hydroxyethyl acrylate (2-HEA) were added to a 1 L reactor equipped with a cooling device to facilitate temperature control. . Subsequently, 180 parts by weight of ethyl acetate (EAc) was added to the reactor as a solvent, and nitrogen gas was purged for 60 minutes to remove oxygen. Thereafter, the temperature was maintained at 67 ° C., 0.05 parts by weight of AIBN (azobisisobutyronitrile) as a reaction initiator was added, and the reaction was carried out for 8 hours. After the reaction, an acrylic polymer (A) having a solid content concentration of 30% by weight, a weight average molecular weight of 1 million and a molecular weight distribution of 4.9 was prepared by diluting with ethyl acetate.

Manufacturing example  2. Preparation of Acrylic Polymers (B) to (D)

A polymer was prepared according to the method of Preparation Example 1, except that the monomer composition was changed as in Table 1 below.

Acrylic polymer A B C D Monomer
Composition (Unit:
Parts by weight) n-BA 98 98 98 80 2-HEA 2 2 - 20 AA - - 2 - Weight average molecular weight (only) 100 190 100 100 Molecular weight distribution 4.9 5.5 5.4 4.9 n-BA: Butyl acrylate
2-HEA: 2-hydroxyethyl acrylate
AA: Acrylic acid

Example  One

Preparation of the first pressure sensitive adhesive

100 parts by weight of acrylic polymer (A), 3 parts by weight of polyfunctional crosslinking agent (TDI isocyanate, Coronate L, manufactured by Nippon Polyurethane (Japan)), polyfunctional acrylate (trifunctional urethane acrylate, Aronix M-315, Dongwoo Common agent) 100 parts by weight, thermal initiator (BPO, benzyl peroxide) 3 parts by weight and silane coupling agent (M812, coupling agent having a beta-cyanoacetyl group, LG Chemical) 0.1 parts by weight so that the solid content concentration is 30% by weight. It mix | blended with the solvent and manufactured the 1st adhesive composition. The pressure-sensitive adhesive composition was then coated on a release treated surface of a release treated PET (poly (ethyleneterephthalate)) film (thickness: 38 μm, MRF-38, manufactured by Mitsubishi Corporation) to a thickness of 25 μm, followed by an oven at 110 ° C. Dried for 3 min. The tensile modulus before heat treatment of the dried first pressure-sensitive adhesive composition was 0.1 MPa at 25 ° C. In order to confirm the increase in the elastic modulus after the heat treatment of the coating layer, that is, formed of the pressure-sensitive adhesive, the tensile modulus after heat treatment alone for 10 minutes at 80 ℃ heat treatment conditions after bonding with the polarizing element was 50 MPa at 25 ℃.

Preparation of the second pressure sensitive adhesive

100 parts by weight of the acrylic polymer (A), 0.01 part by weight of a polyfunctional crosslinking agent (TDI isocyanate, Coronate L, manufactured by Nippon Polyurethane (Japan)) and a silane coupling agent (M812, a coupling agent having a beta-cyanoacetyl group, LG Chem. 0.1 part by weight of the solvent was added to a solid content concentration of 30% by weight to prepare a second pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition was then coated on a release treated surface of a release treated PET (poly (ethyleneterephthalate)) film (thickness: 38 μm, MRF-38, manufactured by Mitsubishi Corporation) to a thickness of 25 μm, followed by an oven at 110 ° C. Dried for 3 minutes to form a second pressure-sensitive adhesive layer. The tensile elasticity modulus of the formed 2nd adhesive layer was 0.06 MPa at 25 degreeC.

Preparation of Polarizer

The polyvinyl alcohol-based resin film was stretched, dyed with iodine, and treated with an aqueous boric acid solution to prepare a polarizer. Subsequently, a 60 μm-thick Triacetyl cellulose (TAC) film was attached to one surface of the polarizer with an aqueous polyvinyl alcohol adhesive. Subsequently, in the polyvinyl alcohol-based polarizer, the prepared first pressure-sensitive adhesive layer (before heat treatment) was laminated on the surface to which the TAC film was not attached, and heat-treated at 80 ° C. for 10 minutes, and then the second pressure-sensitive adhesive on the first pressure-sensitive adhesive layer. The layers were laminated to prepare a polarizing plate (structure: TAC film-based polyvinyl alcohol-based adhesive layer-polarizer-first pressure-sensitive adhesive layer-second pressure-sensitive adhesive layer).

Example  2 to 7 and Comparative example  1 and 2

Except for changing the pressure-sensitive adhesive composition as shown in Tables 2 and 3, a polarizing plate was prepared in the same manner as in Example 1. However, in the comparative example, the adhesive layer of the single layer structure of the 1st adhesive which was not a two layer structure was formed.

Example One 2 3 4 5 6 7

My
One
point
Cling
My


point
Cling
My
article
castle
water

Acrylic polymer class A B C D A A A Acrylic polymer content 100 100 100 100 100 100 100 Multifunctional Crosslinker Content 3 3 3 3 3 3 3 MFA1 content 100 100 100 100 100 - 100 MFA2 content - - - - - 100 - Thermal initiator content 3 3 3 3 3 3 3 Silane Coupling Agent Content 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Tensile Modulus Before Heat Treatment 0.1 1 or less 1 or less 1 or less 1 or less 1 or less 1 or less cohesion
My Thickness (㎛) 25 25 25 25 25 25 25 Tensile Modulus after Heat Treatment 50 50 70 300 60 500 50

My
2
point
Cling
My

point
Cling
My
article
castle
water
Acrylic polymer class A A A A A A C Acrylic polymer content 100 100 100 100 100 100 100 Multifunctional Crosslinker Content 0.01 0.01 0.01 0.01 0.01 0.01 0.01 MFA1 content - - - - 10 - - Photoinitiator Content - - - - One - - Silane Coupling Agent Content 0.1 0.1 0.1 0.1 0.1 0.1 0.1 UV curing method × × × × ○ × × cohesion
My Thickness (㎛) 25 25 25 25 25 25 25 Tensile modulus 0.06 0.06 0.06 0.06 0.6 0.06 0.06 Content unit: Weight portion
Multifunctional Cross-linking agent : TDI Isocyanate crosslinking agent ( Coronate  L, Nippon Made in polyurethane )
MFA1 : Trifunctional  Urethane acrylate ( Aronix  M-315, Dongwoo Trading Festival )
MFA2 : 6-functionality  urethane Acrylate ( UA  306I, Kyoeisha Priests)
Ten initiators Benzyl peroxide BPO )
Photoinitiator : Hydroxycyclohexylphenyl  Ketone Irg  184, F * UCK Specialty chemical )
Silane Coupling agent : Beta cyanoacetyl group  Branch Silane Coupling agent ( M812 , LG Chemicals)
Tensile Modulus: Tensile Modulus at 25 ° C, Unit: MPa

Comparative example One 2

My
One
point
Cling
My


point
Cling
My
article
castle
water

Acrylic polymer class A A Acrylic polymer content 100 100 Multifunctional Crosslinker Content 3 3 MFA1 content 100 - MFA2 content - 100 Thermal initiator content - - Silane Coupling Agent Content 0.1 0.1 Tensile Modulus Before Heat Treatment 0.06 0.06 cohesion
My Thickness (㎛) 25 25 Tensile Modulus after Heat Treatment 0.06 0.06 Content unit: Weight portion
Multifunctional Cross-linking agent : TDI Isocyanate crosslinking agent ( Coronate  L, Nippon Made in polyurethane )
MFA1 : Trifunctional  Urethane acrylate ( Aronix  M-315, Dongwoo Trading Festival )
MFA2 : 6-functionality  urethane Acrylate ( UA  306I, Kyoeisha Priests)
Ten initiators Benzyl peroxide BPO )
Photoinitiator : Hydroxycyclohexylphenyl  Ketone Irg  184, F * UCK Specialty chemical )
Silane Coupling agent Beta Cyanoacetyl group  Branch Silane Coupling agent ( M812 , LG Chemicals)
Tensile Modulus: Tensile Modulus at 25 ° C, Unit: MPa

Physical properties of the pressure-sensitive adhesive layer or the polarizing plate of the Examples and Comparative Examples were measured and the results are summarized in Table 4 below.

Peel force
(N / 25mm) Re-peelability Heat resistant and durable Wet heat
durability Water resistance Light transmission
Uniformity


Example


One 500 ○ ○ ○ ○ ◎ 2 500 ○ ○ ○ ○ ◎ 3 500 ○ ○ ○ ○ ◎ 4 500 ○ ○ ○ ○ ◎ 5 400 ○ ○ ○ ○ ◎ 6 500 ○ ○ ○ ○ ○ 7 800 ○ ○ ○ ○ ○ Comparative Example
One 50 ○ × × × × 2 500 △ × × × ×

1, 2, 3: polarizer
13, 21, 31: adhesive layer
11: polarizer
12a, 12b: protective film
14: release film

Claims (20)

Polarizer; And a thermal initiator formed on at least one surface of the polarizer and having a half-life temperature of 50 ° C. to 80 ° C. in a decomposed state, and having an adhesive layer having an elastic modulus of 10 MPa to 1,000 MPa at room temperature. The polarizing plate of Claim 1 in which a polarizer is a polarizer which does not have a protective film adhered to at least one surface, and the adhesive layer is directly affixed to the surface in which the protective film of the said polarizer is not affixed. The polarizing plate according to claim 1, wherein the polarizer is a polyvinyl alcohol polarizer. The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive layer satisfies the conditions of the following general formula (1):
[Formula 1]
D = M ₂ -M ₁ > 9 MPa
In General Formula 1, M ₁ is an elastic modulus at room temperature measured after forming the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer on one surface of the polarizer, and M ₂ is an adhesive attached to the polarizer. It is an elasticity modulus at normal temperature measured after heat-processing a layer or the layer of an adhesive composition for 10 minutes at the temperature of 80 degreeC. The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive layer comprises a crosslinked structure of a thermosetting component and a crosslinked structure of a radical polymerizable component. The polarizing plate according to claim 5, wherein the crosslinked structure of the thermosetting component is an acrylic polymer crosslinked by a polyfunctional crosslinking agent, and the crosslinked structure of the radical polymerizable component is a crosslinked polyfunctional acrylate. The polarizing plate according to claim 6, wherein the multifunctional crosslinking agent is included in the pressure-sensitive adhesive layer at 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic polymer. The polarizing plate of claim 6, wherein the multifunctional acrylate is included in the pressure-sensitive adhesive layer at 5 parts by weight to 150 parts by weight with respect to 100 parts by weight of the acrylic polymer. The polarizing plate of claim 6, wherein the thermal initiator is included in the pressure-sensitive adhesive layer at 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic polymer. The method of claim 1, wherein the thermal initiator, azo initiator; Peroxyester compounds; Peroxy dicarbonate compounds; Acyl peroxide; Ketone peroxide; Dialkyl peroxides; Peroxy ketal; Or hydroperoxide. The polarizing plate of Claim 1 which further includes the 2nd adhesive layer formed in the lower part of an adhesive layer, and used for attaching the said polarizing plate to a liquid crystal panel. The polarizing plate according to claim 11, wherein the second pressure sensitive adhesive layer has an elastic modulus of from 0.01 MPa to 1.0 MPa at 25 ° C. 13. Forming a pressure-sensitive adhesive layer or a layer of the pressure-sensitive adhesive composition on one surface of the polarizer, the thermal initiator having an undecomposed state having a half-life temperature of 50 ° C. to 80 ° C. for 10 hours, and an elastic modulus at 25 ° C. of 1 MPa or less; And heat treating the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition to increase the elastic modulus at room temperature of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition to 10 MPa to 1,000 MPa. The manufacturing method of the polarizing plate of Claim 13 whose surface of the polarizer with which an adhesive layer is affixed is the surface of the polarizer with which the protective film is not attached. The method of claim 13, wherein the forming of the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition comprises: an acrylic polymer, a polyfunctional crosslinking agent, a polyfunctional radical polymerizable compound, and a pressure initiator comprising a thermal initiator having a 10-hour half-life temperature of 50 ° C. to 80 ° C. A method of manufacturing a polarizing plate comprising coating a coating solution comprising the composition. The method of claim 15, wherein the forming of the pressure-sensitive adhesive layer or the layer of the pressure-sensitive adhesive composition further comprises curing or semi-curing the coated coating liquid. The method of claim 13, wherein the heat treatment is performed at 40 ° C. to 120 ° C. for 1 minute to 30 minutes. The method of claim 13, further comprising forming a second pressure sensitive adhesive layer under the pressure sensitive adhesive layer after the heat treatment. A liquid crystal panel; And a polarizing plate according to claim 1 attached to one side or both sides of the liquid crystal panel. 20. The liquid crystal display of claim 19, wherein the liquid crystal panel comprises: a passive matrix panel; Active matrix panel; A liquid crystal display device which is a transverse electric field panel or a vertical alignment panel.

Images