KR20100011179A - Pressure-sensitive adhesive composition, polarizers and liquid crystal display comprising the same - Google Patents

Abstract

PURPOSE: A pressure-sensitive adhesive composition is provided to ensure excellent durability in high temperature and/or high humidity conditions, to improve stress relaxation property while maintaining modulus that does not interrupt workability. CONSTITUTION: A pressure-sensitive acrylic adhesive composition comprises (A) an acrylic copolymer containing a monomer of chemical formula 1, (B) an acrylic copolymer containing a monomer of chemical formula 2, and (C) a multifunctional crosslinking agent. When the carbon number of a side chain carbon chain(Cn) of the monomer of the chemical formula 1 is n and the carbon number of a side chain carbon chain(Cm) is m, m and n satisfy the equation: n - m >= 1.

Description

Pressure-sensitive adhesive composition, polarizers and liquid crystal display comprising the above {Pressure-sensitive adhesive composition, polarizers and liquid crystal display comprising the same}

The present invention relates to a pressure-sensitive adhesive composition, a polarizing plate and a liquid crystal display device including the above, and more particularly, a pressure-sensitive adhesive composition, which simultaneously exhibits excellent durability reliability, low light leakage characteristics and workability under high temperature and / or high humidity conditions, and a polarizing plate including the same. And a liquid crystal display device.

Generally, in order to manufacture a liquid crystal display device, a liquid crystal cell and a polarizing plate including a liquid crystal are basically required, and an appropriate adhesive layer or adhesive layer for bonding the above should be used. In addition, a retardation plate, a wide viewing angle compensation plate, a brightness enhancement film, etc. may be additionally attached to the said polarizing plate from a viewpoint of the function improvement of a liquid crystal display device.

The liquid crystal display device as described above includes, as a main structure, a liquid crystal layer that is constantly arranged; It includes a polarizing plate of a multi-layer structure based on a liquid crystal cell composed of a transparent glass plate or a plastic-based plate-like material including a transparent electrode layer, incorporated into an adhesive layer or an adhesive layer. At this time, the polarizing plate is a multi-layered structure including an iodine-based compound or a dichroic polarizing material arranged in a predetermined direction, and a triacetyl cellulose (TAC) protective film formed on both sides for protection of the polarizing element. In addition, the polarizing plate may additionally include a phase difference film or a wide viewing angle compensation film having a unidirectional molecular arrangement.

By the way, each of the above-mentioned films has different physical properties from each other, and thus lacks dimensional stability due to shrinkage or expansion of materials, especially under high temperature or high temperature and high humidity conditions. Therefore, when the polarizing plate is fixed by the pressure-sensitive adhesive, strain stress remains due to shrinkage or expansion of the polarizing plate under high temperature or high temperature and high humidity conditions, and thus light leakage occurs in a portion where the stress is concentrated. In order to improve the light leakage phenomenon, it is necessary to reduce the shrinkage phenomenon of the polarizing plate under severe conditions such as high temperature and / or high humidity conditions, but to remove the stress generated in the liquid crystal panel with the polarizing plate composed of materials having different physical properties. It is very difficult. Another method is to design the adhesive used to have excellent stress relaxation function. As such a method, the method of designing so that creep with respect to the external stress of an adhesive is large and a deformation | transformation is easy is used normally.

For example, Korean Patent Laid-Open Publication No. 1998-079266 discloses a pressure-sensitive adhesive composition for a polarizing plate in which a high molecular weight acrylic copolymer, a low molecular weight acrylic copolymer, and a multifunctional crosslinking agent are blended in a specific ratio. Further, Japanese Patent Laid-Open No. 2002-47468 discloses an adhesive composition comprising a high molecular weight acrylic copolymer containing a functional group, a low molecular weight acrylic copolymer containing no functional group, a crosslinking agent, and a silane compound. Japanese Laid-Open Patent Publication No. 2003-49141 also includes a high molecular weight acrylic copolymer containing a functional group, a medium molecular weight acrylic copolymer containing less than two functional groups, a low molecular weight acrylic copolymer containing no functional group and a crosslinking agent. An adhesive composition is disclosed.

All of the above techniques are methods for designing a so-called soft adhesive, which has a large amount of jungle against external stress and is easily deformed through the addition of a low molecular weight material. However, when the soft adhesive is realized by the addition of a low molecular weight material, the modulus of the final adhesive is lowered, so it is easy to cause an adhesive pit defect when the polarizer is stored in a roll shape, and the adhesive protrudes from the cut end when cutting. Sticking out of the adhesive), or a problem of contamination of the polarizer due to the sticking adhesive occurs. In addition, since the added low molecular weight is easy to move to the panel glass and the TAC interfacial layer, it is very likely that the durability is lowered under severe conditions.

On the other hand, another method for imparting a stress relaxation function is to keep the gel content of the pressure-sensitive adhesive made of a high molecular weight containing a crosslinkable functional group very low.

For example, Japanese Patent Laid-Open No. 2005-298723 discloses a first acrylic copolymer containing a crosslinkable functional group; And it contains the same functional group as the above, and discloses invention which manufactures an adhesive by mix | blending suitably the 2nd acrylic copolymer with relatively small weight ratio. The above technology implements the technical idea of limiting the ratio of the weight of the crosslinkable functional group present in the two types of copolymers blended to a certain range.

That is, attempts are made to sufficiently absorb and compensate for stress caused by dimensional change by using a second copolymer having a relatively low crosslinkable functional group. However, in this technique the crosslinking rate of the two copolymers relative to the crosslinking agent is the same. That is, since there is no selectivity to the first and second copolymers of the crosslinking agent, there may arise a problem of ambiguity of the respective properties in the pressure-sensitive adhesive, whereby the second copolymer absorbs and relaxes the stress caused by the dimensional change. There is a problem that the function of.

The present invention is to solve the above-mentioned problems of the prior art, and does not cause a decrease in durability reliability occurring under high temperature and / or high humidity conditions, and does not significantly reduce the modulus of the pressure-sensitive adhesive has excellent workability, stress relaxation characteristics It is an object of the present invention to provide a pressure-sensitive adhesive composition, a polarizing plate comprising the above, and a liquid crystal display device having excellent low light leakage characteristics through improvement.

The present invention, as a means for solving the above problems, an acrylic copolymer (A) containing a monomer of the formula (1);

Acrylic copolymer (B) containing a monomer of formula (2); And a polyfunctional crosslinking agent (C), wherein the carbon number of the carbon chain (Cn) linked to the functional group in the monomer of Formula 1 is n, and the carbon number of the carbon chain (Cm) linked to the functional group in the monomer of Formula 2 is m When n and m satisfy the relationship of the following formula (1), the weight part of the monomer of the formula (1) contained in the acrylic copolymer (A) is A and is included in the acrylic copolymer (B). When the weight part of the monomer of Formula 2 is set to B, the above provides an acrylic pressure-sensitive adhesive composition satisfying the relationship of the following formula (2).

Equation (1): n-m ≥ 1

Equation (2): 0.5 parts by weight ≤ A-B ≤ 5.0 parts by weight

     [Formula 1] [Formula 2]

In Formulas 1 and 2, R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, Func represents a functional group capable of crosslinking with a polyfunctional crosslinking agent, and Cn and Cm each represent a carbon chain composed of n and m carbons.

It is preferable that the said adhesive composition also has the gel fraction represented by following formula (3) is 30 to 90%, and the expansion ratio represented by following formula (4) is 30 to 180.

Formula (3): gel fraction (%) = G / Ad × 100

Equation (4) Expansion Ratio = S / G

In the formulas (3) and (4), Ad represents the mass of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition, G represents the dry mass of the insoluble fraction of the pressure-sensitive adhesive after 48 hours of immersion with ethyl acetate at room temperature, and S is at room temperature. The mass of insoluble fraction (mass of insoluble fraction of the adhesive plus the mass of solvent infiltrated) is expanded by ethyl acetate after 48 hours of immersion with ethyl acetate.

The pressure-sensitive adhesive composition of the present invention also the acrylic copolymer (A) is 80 to 99.8 parts by weight of (meth) acrylic acid ester monomer having a hydrocarbon group of 1 to 14 carbon atoms; And 0.6 to 5 parts by weight of monomer of Formula 1; The acrylic copolymer (B) is 80 to 99.8 parts by weight of a (meth) acrylic acid ester monomer having a hydrocarbon group of 1 to 14 carbon atoms; And 0.01 to 2.5 parts by weight of monomer of formula (2).

In the pressure-sensitive adhesive composition, the multifunctional crosslinking agent (C) may be at least one selected from the group consisting of an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate compound, which is a total of 100% of acrylic copolymers (A) and (B). It is preferably included in an amount of 0.01 to 10 parts by weight with respect to parts by weight.

The present invention is another means for solving the above problems, a polarizing film; And a pressure-sensitive adhesive polarizing plate formed on one or both surfaces of the polarizing film, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention.

The pressure-sensitive adhesive polarizing plate of the present invention may further include at least one functional layer selected from the group consisting of a protective layer, a reflective layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film.

The present invention is another means for solving the above problems, a liquid crystal cell; And a liquid crystal panel having an adhesive polarizing plate according to the present invention bonded to one or both surfaces of the cell.

In the present invention, by using two kinds of acrylic copolymers having different functional groups for the same crosslinking agent, the gel content of the final pressure-sensitive adhesive, the molecular weight and molecular weight distribution of the sol eluted by the solvent is controlled to the optimum range can do. Accordingly, in the present invention, the pressure-sensitive adhesive composition having excellent durability in high temperature and / or high humidity conditions and excellent stress relaxation function while maintaining modulus at a level that does not impair workability is excellent in low light leakage properties. It can provide the polarizing plate and liquid crystal display device containing.

The present invention is an acrylic copolymer (A) containing a monomer of formula (1);

Acrylic copolymer (B) containing a monomer of formula (2); And

A polyfunctional crosslinking agent (C),

When the carbon number of the side chain carbon chain (Cn) of the monomer of Formula 1 is n and the carbon number of the side chain carbon chain (Cm) of the monomer of Formula 2 is m, n and m are represented by the following formula (1) Satisfying relationships,

When the weight part of the monomer of the formula (1) contained in the acrylic copolymer (A) is A, and the weight part of the monomer of the formula (2) contained in the acrylic copolymer (B) is B, wherein A and B are represented by the following formulas: It is related with the acrylic adhesive composition which satisfy | fills the relationship of (2).

Equation (1): n-m ≥ 1

Equation (2): 0.5 parts by weight ≤ A-B ≤ 5.0 parts by weight

     [Formula 1] [Formula 2]

In Formulas 1 and 2, R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, Func represents a functional group capable of crosslinking with a polyfunctional crosslinking agent, and Cn and Cm each represent a carbon chain composed of n and m carbons.

In the present invention, in the pressure-sensitive adhesive composition comprising an acrylic copolymer, an acrylic copolymer (A) containing a functional group having a relatively fast crosslinking rate with respect to the same crosslinking agent at the time of curing and an acrylic group containing a functional group having a relatively slow crosslinking rate It is characterized by using the copolymer (B) together. Accordingly, in the present invention, it is possible to control the gel content of the final pressure-sensitive adhesive, the molecular weight and molecular weight distribution of the sol eluted by the solvent in the optimum range, and excellent durability and durability at high temperature and / or high humidity conditions It is possible to provide a pressure-sensitive adhesive composition excellent in low light leakage properties while maintaining a modulus (modulus) that does not inhibit the properties to improve the stress relaxation function.

Hereinafter, the pressure-sensitive adhesive composition according to the present invention will be described in more detail.

The pressure-sensitive adhesive composition of the present invention is characterized by blending two kinds of acrylic copolymers (A and B) each containing different functional groups with different reaction rates for the same crosslinking agent. That is, the acrylic copolymer (A) included in the composition of the present invention contains a relatively large amount of functional groups having a relatively high reaction rate (crosslinking rate) with respect to the multifunctional crosslinking agent (C), and thus is compact through a selective and fast crosslinking reaction. By forming a crosslinked structure, it provides excellent durability reliability in harsh conditions. In addition, the acrylic copolymer (B) contains relatively few functional groups having a relatively low reaction rate (crosslinking rate) with respect to the multifunctional crosslinking agent (C), thereby forming a loose crosslinked structure, thereby improving the stress relaxation characteristics of the pressure-sensitive adhesive. Workability can be improved without offsetting.

In the present invention, control of the crosslinking structure is very important. In other words, if the crosslinked structure is very dense even at a similar gel content, the durability of the uncrosslinked polymer is less likely to penetrate between the crosslinked structures, thereby significantly reducing the durability. On the other hand, if the crosslinked structure is too loose, the uncrosslinked polymer can easily penetrate between the crosslinked structures, but when the force is applied to the pressure-sensitive adhesive, the uncrosslinked polymer easily exits between the crosslinked structures and thus also has a problem in that the durability reliability is lowered. Accordingly, in the present invention, a dense crosslinked structure and a loose crosslinked structure are simultaneously formed and appropriately distributed to provide an adhesive having excellent durability reliability, stress relaxation characteristics and workability at the same time.

Accordingly, the acrylic copolymers (A) and (B) included in the pressure-sensitive adhesive composition of the present invention include monomers represented by the following formulas (1) and (2), respectively.

     [Formula 1] [Formula 2]

In Formulas 1 and 2, R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, Func represents a functional group capable of crosslinking with a polyfunctional crosslinking agent, and Cn and Cm each represent a carbon chain composed of n and m carbons.

Specific examples of the functional group capable of crosslinking with the multifunctional crosslinking agent in formulas (1) and (2) may be hereinafter referred to as "crosslinkable functional group" include carboxyl groups or hydroxy groups, and from the standpoint of mixing of both copolymers, The hydroxyl group is more preferable.

In the monomers of Formulas 1 and 2, the carbon number of the side chain carbon chains (Cn and Cm) connecting the crosslinkable functional groups satisfies the relationship of the following formula (1).

Equation (1): n-m ≥ 1

By satisfying the above formula (1), the acrylic copolymers (A) and (B) have a difference in the number of carbons in the side chain of 1 or more, whereby a difference in the spatial hiding of the functional group occurs, resulting in the same crosslinking agent (C). The difference in reactivity is shown. That is, the reaction with the crosslinking agent (C) may be preferentially progressed and concentrated in the copolymer (A) containing the monomer of Formula 1 having a long carbon number in the side chain, thereby forming a dense crosslinked structure. On the other hand, the copolymer (B) comprising the monomer of formula (2) having a short carbon number in the side chain reacts with the copolymer (A) and with the small amount of the crosslinking agent (C) remaining, so that the crosslinking formed by the copolymer (A) Compared with the structure, a loose crosslinked structure is formed. Such a reactivity difference according to the number of side chain carbons occurs when the difference in the number of side chain carbons is 1 or more, as in the formula (1), and the difference is more preferably 2 or more, and most preferably 4 or more. When the value of "n-m" in said Formula (1) is less than 1, the difference of the reactivity of the crosslinking agent with respect to both copolymers (A) and (B) is lost, and a crosslinking reaction is selective to a copolymer (A), It is difficult to obtain a dense crosslinked structure that is formed while being preferentially concentrated, thereby making it difficult to form a crosslinked structure having both excellent durability reliability and stress relaxation characteristics.

In the pressure-sensitive adhesive composition of the present invention, when the weight part of the monomer of formula (1) included in the acrylic copolymer (A) is A, and the weight part of the monomer of formula (2) included in the acrylic copolymer (B) is B, The above satisfies the relationship of the following formula (2).

Equation (2): 0.5 parts by weight ≤ A-B ≤ 5.0 parts by weight

When the value of said Formula (2) "A-B" is smaller than 0.5 weight part, the content of the functional group which will form a loose crosslinked structure in an adhesive will become too high, and it will become difficult to show the characteristic, and, thereby, stress relaxation characteristic will become There is a risk of deterioration. Moreover, when the value of "A-B" exceeds 5.0 weight part, the content of the functional group which will form a dense crosslinked structure will be too large, and there exists a possibility that durability reliability may worsen.

It is preferable that the gel fraction represented by following formula (3) of the adhesive composition of this invention is 30 to 90%, and it is more preferable that it is 40 to 80%.

Formula (3): gel fraction (%) = G / Ad × 100

In Formula (3), Ad represents the mass of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition of the present invention, and G represents the dry mass of the insoluble content of the pressure-sensitive adhesive after 48 hours of immersion with ethyl acetate at room temperature.

If the gel fraction represented by the above formula (3) is less than 30%, the gel content may drop too much, and the amount of the uncrosslinked polymer may increase, thereby reducing workability. Moreover, when the said gel fraction exceeds 90%, there exists a possibility that the stress relaxation characteristic of an adhesive may fall large.

Moreover, it is preferable that the expansion ratio represented by following formula (4) is 30-180, and, as for the adhesive composition of this invention, it is more preferable that it is 50-150.

Equation (4) Expansion Ratio = S / G

In the formula (4), S is the mass of the insoluble fraction expanded by ethyl acetate after 48 hours of immersing the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition of the present invention with ethyl acetate (insoluble mass of the adhesive + mass of infiltrated solvent). ), G is as defined in the formula (3).

When the expansion ratio represented by the above formula (4) is less than 30, the crosslinked structure may be too dense, and the stress relaxation property of the pressure-sensitive adhesive may be lowered. When the expansion ratio exceeds 180, the crosslinked structure may be too loose and durability may be lowered. have.

The pressure-sensitive adhesive composition as described above can be prepared by mixing two kinds of acrylic copolymers (A) and (B) in a certain weight ratio to have a suitable crosslinked structure. Although it does not specifically limit, if the composition of copolymer (A) and (B) differs in the above, there exists a possibility that a problem may arise in mixing property, It is preferable to have a similar composition as possible. That is, the acrylic copolymer (A) is 80 to 99.8 parts by weight of (meth) acrylic acid ester monomer having a hydrocarbon group (ex. Alkyl group) having 1 to 14 carbon atoms; And 0.6 to 5 parts by weight of the monomer of Formula 1, and the acrylic copolymer (B) is 80 to 99.8 parts by weight of (meth) acrylic acid ester monomer having a hydrocarbon group (ex. Alkyl group) having 1 to 14 carbon atoms. ; And 0.01 to 2.5 parts by weight of monomer of formula (2).

As mentioned above, it is preferable that the acrylic copolymers (A) and (B) of this invention contain the (meth) acrylic acid ester monomer which has a C1-C14 hydrocarbon group (ex. Alkyl group). In this case, if the carbon number of the hydrocarbon group of the monomer is too small or too large, the glass transition temperature may be too high or the adhesion may be difficult to control. Preferably, the hydrocarbon group has 1 to 14 carbon atoms. no. Specific examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, t-butyl ( Meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl ( One or more selected from the group consisting of meth) acrylate, tetradecyl (meth) acrylate, benzyl (meth) acrylate and phenoxyethyl (meth) acrylate, but is not limited thereto. Such a (meth) acrylic acid ester monomer is preferably included in an amount of 80 to 99.8 parts by weight in the acrylic copolymers (A) and (B) of the present invention. If the content is less than 80 parts by weight, there is a fear that the initial adhesive strength of the pressure-sensitive adhesive is lowered, if it exceeds 99.8 parts by weight, there is a fear that a problem in durability due to the cohesive force is lowered.

The acrylic copolymers (A) and (B) of the present invention include monomers represented by the above formulas (1) and (2) together with the (meth) acrylic acid ester monomers. By containing the monomers of Formulas (1) and (2), the adhesive force and cohesive force of the pressure-sensitive adhesive can be adjusted. Specific examples of the monomers represented by the above formulas (1) and (2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6 -Hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, 2-hydroxypropylene glycol (meth) acrylate, acrylic acid, methacrylic acid With 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyl acid, acrylic acid duplex, itaconic acid, maleic acid and maleic anhydride One or more selected from the group consisting of, but is not limited thereto. Of the monomers as described above, the monomer represented by the formula (1) is preferably contained in an amount of 0.6 to 5 parts by weight in the acrylic copolymer (A). When the content is less than 0.6 part by weight, it becomes difficult to satisfy the relationship of the above formula (2), making it difficult to give a dense crosslinked structure to the pressure-sensitive adhesive, which may lower the durability reliability. Moreover, when the said content exceeds 5 weight part, a crosslinked structure will become too dense and the copolymer of a loose crosslinked structure will not penetrate easily, and there exists a possibility that durability reliability may fall. In addition, in the above case, it is difficult to achieve the gel fraction and expansion ratio intended in the present invention, and there is a fear that the workability is lowered due to the formation of a gel due to the increase in the crosslinking rate.

In addition, the monomer of Formula 2 is preferably contained in an amount of 0.01 to 2.5 parts by weight in the acrylic copolymer (B). If the content is less than 0.01 part by weight, the degree of crosslinking that the copolymer (B) implements may be degraded, and workability may be lowered. If the content is more than 2.5 parts by weight, a relatively loose crosslinked structure may be obtained compared to the copolymer (A). It may be difficult to implement.

The acrylic copolymers (A) and / or (B) of the present invention may also be further copolymerized with functional monomers. The monomer is added for the purpose of controlling the glass transition temperature of the pressure-sensitive adhesive and other functionalities, it is preferable that the monomer is represented by the following formula (3).

[Formula 3]

Wherein R 2 to R 4 each independently represent hydrogen or alkyl, and R 5 represents cyano; Phenyl unsubstituted or substituted with alkyl; Acetyloxy; Or COR 6, wherein R 6 represents amino or glycidyloxy unsubstituted or substituted with alkyl or alkoxyalkyl.

Alkyl or alkoxy in the definition of R1 to R6 in the above formula means alkyl or alkoxy having 1 to 8 carbon atoms, preferably methyl, ethyl, methoxy, ethoxy, propoxy or butoxy.

Specific examples of the monomer represented by Formula 3 include nitrogen-containing monomers such as acrylonitrile, (meth) acrylamide, N-methyl (meth) acrylamide or N-butoxy methyl (meth) acrylamide; Styrene-based monomers such as styrene or methyl styrene; Carboxylic acid vinyl esters such as vinyl acetate; Or glycidyl (meth) acrylate, and the like, but is not limited thereto. The monomers may be used alone or in combination of two or more. When such a monomer is included in the acrylic copolymer (A) or (B) of the present invention, the content thereof is preferably 20 parts by weight or less. When the content exceeds 20 parts by weight, there is a fear that the flexibility and / or peeling force of the pressure-sensitive adhesive composition is lowered.

It is preferable that an acryl-type copolymer (A) is contained in the composition in the quantity of 10-40 weight part, and it is preferable that an acryl-type copolymer (B) is contained in the amount of 60-100 weight part as mentioned above. If the content of the copolymer (A) is less than 10 parts by weight or the content of the copolymer (B) is more than 100 parts by weight, the durability may be lowered. In addition, when the content of the copolymer (A) is more than 40 parts by weight or the content of the copolymer (B) is less than 60 parts by weight, there is a fear that the stress relaxation characteristics are lowered.

The adhesive composition of this invention contains the polyfunctional crosslinking agent (C) which has a different reactivity with respect to the above two types of acrylic copolymers (A) and (B). The crosslinker reacts with the crosslinkable functional group of the acrylic copolymer to increase the cohesion of the pressure-sensitive adhesive. The kind of specific crosslinking agent (C) used at this time is not specifically limited, For example, general crosslinking agents, such as an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an aziridine type crosslinking agent, and a metal chelate type compound, can be used.

Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethylxylene diisocyanate, naphthalene diisocyanate and any of the above. At least one selected from the group consisting of reactants with one polyol (ex. Trimethylol propane); Examples of epoxy crosslinkers include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidyl ethylenediamine and glycerin diglycidyl ether. One or more selected from the group consisting of; Examples of the aziridine crosslinking agent include N, N'-toluene-2,4-bis (1-aziridinecarboxide), N, N'-diphenylmethane-4,4'-bis (1-aziridinecarbox Id), triethylene melamine, bisisoprotaloyl-1- (2-methylaziridine), and one or more selected from the group consisting of tri-1-aziridinylphosphine oxide. In addition, examples of the metal chelate-based compound may be 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. It is not limited.

Such polyfunctional crosslinking agent (C) is preferably included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer (A) and (B) in total. When the content is less than 0.01 part by weight, the crosslinking reaction does not proceed well, and the cohesive force of the pressure-sensitive adhesive may be lowered. When the content is more than 10 parts by weight, the crosslinking reaction proceeds excessively and the stress relaxation characteristic is deteriorated, There is a fear that the durability is lowered, such as lifting.

The pressure-sensitive adhesive composition of the present invention may further include 0.005 to 5 parts by weight of coupling agent based on 100 parts by weight of the acrylic copolymer (A) and (B) in total. By including a coupling agent in this way, adhesion | attachment stability can be improved at the time of sticking to a glass plate etc., and heat resistance and moisture resistance characteristics can be improved. The coupling agent contributes to improving the adhesion reliability, especially when left for a long time under high temperature and high humidity. The specific kind of the above coupling agent is not particularly limited, and for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-mercapto propyl trimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyl triethoxysilane, γ-aminopropyltrimeth Oxysilane, gamma -aminopropyl triethoxysilane, 3-isocyanatepropyl triethoxysilane, gamma -acetoacetatepropyltrimethoxysilane, and the like can be used, and one or more of the above can be mixed and used. The silane coupling agent is preferably included in an amount of 0.005 to 5 parts by weight in the pressure-sensitive adhesive composition. When the content is less than 0.005 parts by weight, there is a fear that the effect of increasing the adhesive strength is insignificant, and when the content is more than 5 parts by weight, bubbles or peeling phenomenon may occur and durability may be lowered.

The pressure-sensitive adhesive composition of the present invention may further include 1 to 100 parts by weight of a tackifying resin with respect to 100 parts by weight of the acrylic copolymer (A) and (B) in terms of adhesion performance control. Examples of tackifying resins that can be used at this time include (hydrogenated) hydrocarbon resins, (hydrogenated) rosin resins, (hydrogenated) rosin ester resins, (hydrogenated) terpene resins, (hydrogenated) terpene phenolic resins, polymerized rosin resins and polymerizations Rosin ester resin can be mentioned, One type or a mixture of 2 or more types of the above can be used. Preferably, the tackifying resin is included in the composition in an amount of 1 to 100 parts by weight. If the content is less than 1 part by weight, the effect of addition may be insignificant. When the content is greater than 100 parts by weight, the compatibility and / or cohesion may be improved. There is a risk of deterioration.

The pressure-sensitive adhesive composition of the present invention may further include one or more additives selected from the group consisting of an epoxy resin, a curing agent, a UV stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, and a plasticizer, in addition to the above-described components. Can be. Acrylic pressure-sensitive adhesive composition of the present invention containing the above components can be prepared through a conventional method in the art, it is particularly preferred to use a method such as thermal curing or light curing.

The method for producing the pressure-sensitive adhesive composition containing the above components is not particularly limited, and for example, after preparing two types of acrylic copolymers (A) and (B) for having a crosslinked structure suitable for the present invention, This can be manufactured by mixing in a fixed weight ratio and further mixing components, such as a crosslinking agent (C).

At this time, the acrylic copolymers (A) and (B) can be prepared using a general method in the art, and examples thereof include solution polymerization, photopolymerization, bulk polymerization, suspension polymerization or emulsion polymerization. Although not particularly limited, in the present invention, it is preferable to prepare the acrylic copolymer using a solution polymerization method, specifically, the polymerization temperature is set to 50 to 140 ° C, and the polymerization initiator is uniformly mixed in a state where the monomers are uniformly mixed. It is preferable to advance the reaction by adding. The kind of polymerization initiator which can be used at this time is not specifically limited, For example, Azo-type polymerization initiators, such as azobisisobutyronitrile or azobiscyclohexanecarbonitrile; And peroxides, such as benzoyl peroxide or acetyl peroxide can be used individually or in mixture of 2 or more types.

In the present invention, the acrylic copolymers (A) and (B) may be prepared in the same manner as described above, and the adhesive compositions may be prepared by mixing them with a crosslinking agent (C) by a conventional method. At this time, it is preferable that the polyfunctional crosslinking agent is controlled so that the crosslinking reaction with the functional group of the acrylic copolymer hardly progresses in the compounding process from the viewpoint of performing uniform coating operation. Such a crosslinking agent forms a crosslinked structure in the drying and aging process after the coating operation to improve the cohesion, thereby improving the adhesive properties and cuttability (tacktability) of the adhesive product.

The present invention also provides a polarizing film; And

It relates to an adhesive polarizing plate formed on one or both surfaces of the polarizing film, and comprising an adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention described above.

The kind of polarizing film or polarizing element constituting the pressure-sensitive adhesive polarizing plate of the present invention is not particularly limited. For example, as said polarizing film, the film manufactured by extending | stretching and manufacturing polarizing components, such as iodine or a dichroic dye, in the film which consists of polyvinyl alcohol-type resins can be used. As the polyvinyl alcohol-based resin, polyvinyl alcohol, polyvinyl formal, polyvinyl acetal or saponified product of ethylene vinyl acetate copolymer may be used. In addition, the thickness of the polarizing film is also not particularly limited, and may be formed in a conventional thickness.

In the pressure-sensitive adhesive polarizing plate of the present invention, further, a cellulose film such as triacetyl cellulose on both surfaces of the polarizing film; Polyester film such as polycarbonate film or polyethylene terephthalate film; Polyether sulfone-based film; And / or a protective film such as a polyethylene film, a polypropylene film, or a polyolefin film having a cyclo or norbornene structure or a polyolefin film such as an ethylene propylene copolymer. At this time, the thickness of the protective film is also not particularly limited, and may be formed in a conventional thickness.

The method of forming the pressure-sensitive adhesive layer on the polarizing film as described above is not particularly limited, and for example, the method of applying the pressure-sensitive adhesive composition to the film with a bar coater or the like to form the pressure-sensitive adhesive layer, or the pressure-sensitive adhesive composition once the peelable base material After apply | coating to a surface and forming an adhesive layer, the method etc. which transfer and mature the said adhesive layer to the polarizing film surface using the said peelable base material can be used.

In addition, in the present invention, it is preferable to use after removing the bubble-inducing components such as volatile components or reaction residues inside the composition when forming the pressure-sensitive adhesive layer. If the crosslinking density or molecular weight is too low and the modulus of elasticity falls, there is a concern that small bubbles existing between the glass plate and the pressure-sensitive adhesive layer in the high temperature state become large to form scatterers therein.

The polarizing plate of the present invention may further include at least one functional layer selected from the group consisting of a protective layer, a reflective layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film, and contains an adhesive composition according to the present invention. An adhesive may be attached to each of the functional layers.

The present invention also provides a liquid crystal cell; And a liquid crystal panel having a polarizing plate according to the present invention bonded to one or both surfaces of the cell.

The type of liquid crystal cell constituting the liquid crystal display device of the present invention as described above is not particularly limited, such as TN (Twisted Neumatic), STN (Super Twisted Neumatic), IPS (In Plane Switching) or VA (Vertical Alignment) It includes all common liquid crystal cells. In addition, the kind and other manufacturing method of the other structure contained in the liquid crystal display device of this invention are not specifically limited, either, The general structure of this field can be employ | adopted and used without a restriction | limiting.

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

Production Example  1. Preparation of Acrylic Copolymer (A1)

As shown in Table 1, 98.5 parts by weight of n-butyl acrylate (n-BA) and 4-hydroxy butyl acrylate (4- HB) was added a monomer mixture containing 1.5 parts by weight, then 120 parts by weight of ethyl acetate (EAc) as a solvent. Nitrogen gas was purged for 60 minutes for oxygen removal, the temperature was maintained at 60 ° C, and 0.03 parts by weight of azobisisobutyronitrile (AIBN), a reaction initiator, was added and reacted for 8 hours. After completion of the reaction, the mixture was diluted with ethyl acetate (EAc) to prepare an acrylic copolymer (A1) having a solid content concentration of 15% by weight, a weight average molecular weight of 1.6 million, and a molecular weight distribution of 4.9.

Production Example  2. Preparation of Acrylic Copolymers (A2 to A5 and B1 to B6)

An acrylic copolymer (A2 to A5 and B1 to B6) was prepared in the same manner as in Preparation Example 1, except that the composition of the monomer constituting the acrylic copolymer was adjusted as shown in Tables 1 and 2 below.

TABLE 1

A1 A2 A3 A4 A5 n-BA 98.5 97 98.5 98 98.5 2-HEA - - - - 1.5 4-HBA 1.5 3 - - - 6-HHA - - 1.5 2 - AIBN 0.03 0.03 0.03 0.03 0.03 EAc 120 100 100 120 100 M _w (only) 162 165 170 155 160 Molecular weight distribution 4.8 5.3 5.4 4.9 5.6 n- BA n-butyl Acrylate /2- HEA : 2- Hydroxyethyl Acrylate /4- HBA : 4- Hydroxybutyl Acrylate / 6- HHA 6- Hydroxyhexyl Acrylate Of AIBN : Azobisisobutyronitrile Of EAc : Ethyl acetate / Mw: weight average molecular weight (unit: Parts by weight )

TABLE 2

B1 B2 B3 B4 B5 B6 n-BA 99.5 98.7 99.5 98.7 99.5 100 2-HEA 0.5 1.3 - - - - 4-HBA - - 0.5 1.3 - - 6-HHA - - - - 0.5 - AIBN 0.03 0.03 0.03 0.03 0.03 0.03 EAc 120 100 100 120 120 100 Mw (only) 152 160 150 161 170 151 Molecular weight distribution 4.6 5.4 5.4 4.9 5.3 5.6 n- BA n-butyl Acrylate /2- HEA : 2- Hydroxyethyl Acrylate /4- HBA : 4- Hydroxybutyl Acrylate / 6- HHA 6- Hydroxyhexyl Acrylate Of AIBN : Azobisisobutyronitrile Of EAc : Ethyl acetate / Mw: weight average molecular weight (unit: Parts by weight )

Example  One.

20 parts by weight of the acrylic copolymer A1 prepared in Preparation Example 1 (solid content weight) and 80 parts by weight of the acrylic copolymer B1 (solid content weight) were mixed, followed by tolylene diisocyanate of trimethylolpropane, an isocyanate-based crosslinking agent as a polyfunctional crosslinking agent. 0.1 parts by weight of the adduct (TDI-1) was mixed. In consideration of coating properties, the mixture was diluted to an appropriate concentration, uniformly mixed, and then coated and dried on a release paper to obtain a uniform adhesive layer having a thickness of 30 μm. The pressure-sensitive adhesive layer prepared in step (1) was adhesively processed on an iodine-based polarizing plate having a thickness of 185 μm to prepare a polarizing plate.

Example  2 to 7

A polarizing plate was manufactured in the same manner as in Example 1, except that the composition of the pressure-sensitive adhesive composition was adjusted as in Table 3 below.

Comparative example  1 to 6

A polarizing plate was manufactured in the same manner as in Example 1, except that the composition of the pressure-sensitive adhesive composition was adjusted as in Table 4 below.

TABLE 3

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 A1 20 - - - - - - A2 - 30 - - - - - A3 - - 20 25 - - - A4 - - - - 10 15 15 A5 - - - - - - - B1 80 70 80 - 90 85 - B2 - - - - - - - B3 - - - 75 - - 85 B4 - - - - - - - B5 - - - - - - - B6 - - - - - - - Crosslinking agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 (unit: Parts by weight )

TABLE 4

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 A1 20 - - 20 - 20 A2 - - - - - - A3 - 30 - - 20 - A4 - - - - - - A5 - - 25 - - - B1 - - 75 - - - B2 - - - 80 - - B3 80 - - - - - B4 - - - - 80 - B5 - 70 - - - - B6 - - - - - 80 Crosslinking agent 0.1 0.1 0.1 0.1 0.1 0.1 (unit: Parts by weight )

Tests as shown below were performed for Examples and Comparative Examples prepared as above, and the results are shown in Tables 5 and 6 below.

<Test method>

1.gel Fractional  Measure

The pressure-sensitive adhesive dried through each compounding process of Examples and Comparative Examples was left in a constant temperature and humidity chamber (23 ° C. and 60% RH) for about 10 days, and then about 0.3 g of pressure-sensitive adhesive was placed in a # 200 stainless steel wire mesh, and 100 ml of ethyl acetate It was immersed in and stored for 3 days in the dark at room temperature. Thereafter, the insoluble fraction was separated, and the separated insoluble fraction was dried in an oven at 70 ° C. for 4 hours, and then mass was measured to determine a gel fraction based thereon.

2. Measurement of expansion ratio

After the separation of the insoluble fraction at the measurement of the gel fraction, the weight of the insoluble fraction and the solvent contained (infiltrated) was measured, and then the weight was divided by the mass of the insoluble fraction after drying to determine the expansion ratio. It was.

3. Endurance Reliability

The polarizing plates prepared in Examples and Comparative Examples were cut to a size of 90 mm × 170 mm (width × length) to prepare a specimen, and then, on a glass substrate (size: 110 mm × 190 mm × 0.7 mm), on both sides. The optical absorption axis was attached with the cross. At this time, the pressure applied was about 5 Kg / cm ² , and the clean room work was performed so that no bubbles or foreign matter. In order to determine the heat and moisture resistance of the samples, the mixture was left for 1000 hours at a temperature of 60 ° C. and a relative humidity of 90%, and then observed whether bubbles or peeling occurred. In addition, the heat resistance was observed for 1000 hours at the temperature of 80 ℃ after bubbles or peeling occurred. The sample state was measured after standing for 24 hours at room temperature immediately before evaluation. In addition, after leaving the adhesive polarizing plates prepared in Examples and Comparative Examples 5 months or more, the durability reliability was evaluated in the same manner as described above. At this time, evaluation criteria for reliability are as follows.

○: no bubbles or peeling

△: slight bubble or peeling phenomenon

X: A lot of bubble and peeling phenomenon generate | occur | produce

4. Light transmission  Uniformity ( Light fountain )

The uniformity of the light transmittance was investigated using the same sample as the endurance reliability measurement. Specifically, the polarizing plate (size: 200 mm × 200 mm) is attached to both sides of the glass substrate (size: 210 mm × 210 mm × 0.7 mm) by 90 degrees, and then the part where light leaks out from the dark room using the backlight. Adopted a method to observe the presence of. The uniformity of light transmittance at this time was evaluated based on the following criteria.

⊙: Unevenness of light transmittance is hard to judge

○: slight light transmittance nonuniformity

△: non-uniformity of light transmittance

X: The light non-uniformity is abundant.

5. Adhesive Depressed  Measure

Since the pressure-sensitive adhesive deterioration is smaller as the elastic modulus of the pressure-sensitive adhesive is higher, that is, the storage elastic modulus is higher, the elastic modulus of the pressure-sensitive adhesive is measured to determine whether the pressure is poor. The elastic modulus of the pressure-sensitive adhesive was measured using RMS-800 (Rheometrics (manufactured)). Specifically, storage modulus was measured using a Parallel Plate Fixture having a diameter of 8 mm under conditions of a temperature of 30 ° C., an adhesive thickness of 1 mm, a strain of 10%, and a frequency of 1 rad / sec. Based on the measured storage modulus, it was determined as follows.

5 points | pieces: There is little adhesive deterioration defect

(Storage modulus> 1.8 x 10 ⁴ Pa)

4 points | pieces: There is a little adhesive deterioration

(1.4 × 10 ⁴ Pa <storage modulus <1.7 × 10 ⁴ Pa)

3 points | pieces: Slightly bad adhesive pressure

(1.0 × 10 ⁴ Pa <storage modulus <1.3 × 10 ⁴ Pa)

2 points | pieces: There are many adhesive pressure defects

(0.8 × 10 ⁴ Pa <storage modulus <1.0 × 10 ⁴ Pa)

1 point | piece: Very many adhesive press defects

(0.8 × 10 ⁴ Pa <storage modulus)

6. Adhesive protrusion Protruding ) Measurement

Using a Thompson cutter, the polarizing plates produced in Examples and Comparative Examples were cut, and the degree of protruding from the cut surfaces of each polarizing plate was observed under a microscope, and the following criteria were evaluated.

3 points: Good protruding from the cutting surface (less than 0.2 mm)

2 points: Slightly poor protruding from the cutting surface (0.2 to 0.5 mm)

1 point: The degree of protruding from the cutting surface is severe (more than 0.5mm)

TABLE 5

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 n-m 2 2 4 2 4 4 2 A-B One 2.5 One One 1.5 1.5 1.5 Gel fraction (%) 62 65 55 72 55 65 73 Expansion ratio 98 85 104 50 140 111 80 Durability Reliability ○ ○ ○ ○ ○ ○ ○ Light fountain ⊙ ⊙ ⊙ ○ ⊙ ⊙ ○ Protruding 3 3 3 3 3 3 3 Depression 5 5 5 5 5 5 5 n: contained in A1, A2, A3, A4 or A5 Crosslinkable Functional group  Of monomers chain Carbon number m: contained in B1, B2, B3, B4, B5 or B6 Crosslinkable Functional group  Of monomers chain Carbon number A: contained in A1, A2, A3, A4 or A5 Crosslinkable Functional group  Content of containing monomer B: contained in B1, B2, B3, B4, B5 or B6 Crosslinkable Functional group  Content of containing monomer

TABLE 6

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 n-m 0 0 0 2 2 - A-B One One One 0.2 0.2 - Gel fraction (%) 75 72 75 78 80 16 Expansion ratio 60 71 62 58 55 105 Durability Reliability ○ ○ ○ ○ ○ △ Light fountain × × × × × ⊙ Protruding 3 3 3 3 3 2 Depression 5 5 5 5 5 4 n: contained in A1, A2, A3, A4 or A5 Crosslinkable Functional group  Of monomers chain Carbon number m: contained in B1, B2, B3, B4, B5 or B6 Crosslinkable Functional group  Of monomers chain Carbon number A: contained in A1, A2, A3, A4 or A5 Crosslinkable Functional group  Content of containing monomer B: contained in B1, B2, B3, B4, B5 or B6 Crosslinkable Functional group  Content of containing monomer

As shown in the results of Tables 5 and 6, Examples 1 to 7 according to the present invention have both excellent durability reliability and light leakage characteristics, and further less adhesive sticking and crushing pressure related to workability during manufacture. On the other hand, in Comparative Examples 1 to 3, the difference in the number of carbons of the side chains connecting the crosslinkable functional groups is 0, thus showing no difference in reactivity with respect to the same crosslinking agent, thereby showing a high degree of crosslinking and a relatively low expansion ratio. Accordingly, the pressure-sensitive adhesives of Comparative Examples 1 to 3 did not effectively express excellent stress relaxation characteristics, and the low light leakage characteristics were inferior.

In addition, in Comparative Examples 4 and 5, the content difference between the crosslinkable functional group-containing monomer of the copolymer forming a relatively loose crosslinked structure and the crosslinkable functional group-containing monomer of the copolymer forming a dense crosslinked structure is small (A-B <0.5 parts by weight). As a result, the copolymer having a loose structure contained a large amount of functional groups, making it difficult to express its characteristics, resulting in poor low-light leakage characteristics.

In addition, the comparative example 6 is a case where the copolymer in which the loose crosslinked structure was formed does not have a crosslinkable crosslinking group. Therefore, in the case of Comparative Example 6, the stress relaxation property of the copolymer that does not participate in the crosslinking reaction is expressed, and the light leakage property is excellent, but the low crosslinking degree and the amount of free high molecular weight increase, and thus the durability is low. Pressing and sticking out of the adhesive occurred, it appeared that workability is reduced.

Claims (20)

Acrylic copolymer (A) containing a monomer of formula (1); Acrylic copolymer (B) containing a monomer of formula (2); And A polyfunctional crosslinking agent (C), When the carbon number of the side chain carbon chain (Cn) of the monomer of Formula 1 is n and the carbon number of the side chain carbon chain (Cm) of the monomer of Formula 2 is m, n and m are represented by the following formula (1) Satisfying relationships, When the weight part of the monomer of the formula (1) contained in the acrylic copolymer (A) is A, and the weight part of the monomer of the formula (2) contained in the acrylic copolymer (B) is B, wherein A and B are represented by the following formulas: Acrylic adhesive composition which satisfy | fills the relationship of (2): Equation (1): n-m ≥ 1 Equation (2): 0.5 parts by weight ≤ A-B ≤ 5.0 parts by weight      [Formula 1] [Formula 2]

In Formulas 1 and 2, R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, Func represents a functional group capable of crosslinking with a multifunctional crosslinking agent, and Cn and Cm each represent a carbon chain composed of n and m carbons. The method of claim 1, The pressure-sensitive adhesive composition characterized in that the gel fraction represented by the following formula (3) is 30 to 90%, and the expansion ratio represented by the following formula (4) is 30 to 180: Formula (3): gel fraction (%) = G / Ad × 100 Equation (4) Expansion Ratio = S / G In the formulas (3) and (4), Ad represents the mass of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition, G represents the dry mass of the insoluble fraction of the pressure-sensitive adhesive after 48 hours of immersion with ethyl acetate at room temperature, and S is at room temperature. The mass of insoluble fraction (mass of insoluble fraction of the adhesive plus the mass of solvent infiltrated) is expanded by ethyl acetate after 48 hours of immersion with ethyl acetate. The method of claim 2, Pressure-sensitive adhesive composition, characterized in that the gel fraction is 40 to 80%, the expansion ratio is 50 to 150. The method of claim 1, Acrylic copolymer (A) is 80 to 99.8 parts by weight of (meth) acrylic acid ester monomer having a hydrocarbon group of 1 to 14 carbon atoms; And 0.6 to 5 parts by weight of the monomer of Formula 1; Acrylic copolymer (B) is 80 to 99.8 parts by weight of (meth) acrylic acid ester monomer having a hydrocarbon group of 1 to 14 carbon atoms; And 0.01 to 2.5 parts by weight of monomer of formula (2). The method of claim 4, wherein (Meth) acrylic acid ester monomers having a hydrocarbon group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and butyl (meth). ) Acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl ( Pressure-sensitive adhesive composition, characterized in that at least one selected from the group consisting of meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, benzyl (meth) acrylate and phenoxyethyl (meth) acrylate. The method of claim 4, wherein The monomer represented by the formula (1) or (2) is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) Acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, 2-hydroxypropylene glycol (meth) acrylate, acrylic acid, methacrylic acid, 2- (meth) acrylic At least one selected from the group consisting of royloxy acetic acid, 3- (meth) acryloyloxy propyl acid, 4- (meth) acryloyloxy butyric acid, acrylic acid duplex, itaconic acid, maleic acid and maleic anhydride Adhesive composition characterized by. The method of claim 4, wherein The pressure-sensitive adhesive composition characterized in that the acrylic copolymer (A) or (B) further comprises a monomer represented by the following formula (3): [Formula 3]

Wherein R 2 to R 4 each independently represent hydrogen or alkyl, and R 5 represents cyano; Phenyl unsubstituted or substituted with alkyl; Acetyloxy; Or COR 6, wherein R 6 represents amino or glycidyloxy unsubstituted or substituted with alkyl or alkoxyalkyl. The method of claim 7, wherein The adhesive composition, wherein the functional monomer is a nitrogen-containing monomer, a styrene monomer, a carboxylic acid vinyl ester, glycidyl (meth) acrylate or vinyl acetate. The method of claim 1, The acrylic copolymer (A) is included in an amount of 10 to 40 parts by weight, and the acrylic copolymer (B) is included in an amount of 60 to 100 parts by weight. The method of claim 1, The pressure-sensitive adhesive composition, wherein the multifunctional crosslinking agent (C) is at least one selected from the group consisting of an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate compound. The method of claim 1, The polyfunctional crosslinking agent (C) is included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer (A) and (B) in total. The method of claim 1, The pressure-sensitive adhesive composition, further comprising 0.005 to 5 parts by weight of a coupling agent based on 100 parts by weight of the acrylic copolymer (A) and (B) in total. The method of claim 12, The silane coupling agent is γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyl triethoxysilane, 3-mercaptopropyl trimethoxy group silane, vinyltrimethoxy Silane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3- Pressure-sensitive adhesive composition, characterized in that at least one selected from the group consisting of isocyanate propyl triethoxysilane and γ-acetoacetate propyl trimethoxysilane. The method of claim 1, The adhesive composition which further contains 1-100 weight part of tackifying resin with respect to 100 weight part of acrylic copolymers (A) and (B) in total. The method of claim 14, The tackifying resin is (hydrogenated) hydrocarbon resin, (hydrogenated) rosin resin, (hydrogenated) rosin ester resin, (hydrogenated) terpene resin, (hydrogenated) terpene phenol resin, polymerized rosin resin or polymerized rosin ester resin Pressure-sensitive adhesive composition. The method of claim 1, The pressure-sensitive adhesive composition further comprises at least one selected from the group consisting of an epoxy resin, a curing agent, a UV stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, and a plasticizer. Polarizing film; And An adhesive polarizing plate formed on one side or both sides of the polarizing film, the adhesive layer containing the pressure-sensitive adhesive composition according to any one of claims 1 to 16. The method of claim 17, One or more protective films selected from the group consisting of cellulose-based films, polyester-based films, polyethersulfone-based films and polyolefin-based films are further formed on both sides of the polarizing film. The method of claim 17, A pressure-sensitive adhesive polarizing plate further comprises at least one functional layer selected from the group consisting of a protective layer, a reflection layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film and a brightness enhancement film. Liquid crystal cell; And a liquid crystal panel having a polarizing plate according to claim 17 bonded to one side or both sides of the cell.