WO2014038810A1 - Adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition, and more particularly, to an adhesive composition having excellent durability and an anti-static property and which effectively suppresses the corrosion of a metal layer without containing an additional anti-corrosive agent in that it contains an acryl-based copolymer having a carboxyl group and an ionic anti-static agent having an epoxy group in order to avoid conditions such as detachment, foaming, and exfoliation due to the surface transition of the anti-static agent.

Description

Pressure-sensitive adhesive composition

The present invention improves the compatibility between the antistatic agent and the acrylic copolymer containing no acid, thereby suppressing the bleed out of the antistatic agent, thereby improving the durability, antistatic property and corrosion resistance at the same time. It is about.

In general, a liquid crystal display device (LCD) is provided with a liquid crystal cell and a polarizing plate containing a liquid crystal, and an appropriate pressure-sensitive adhesive layer for bonding them is used. The pressure sensitive adhesive is often used an acrylic pressure sensitive adhesive based on an acrylic copolymer having excellent adhesiveness and transparency.

In the process of attaching the polarizing plate to the liquid crystal cell, peeling the release film from the pressure-sensitive adhesive layer generates static electricity. The generated static electricity affects the alignment of the liquid crystal and causes defects or flows between the liquid crystal cell and the adhesive due to electrostatic attraction. It causes contamination by foreign objects.

In order to improve this, an ionic antistatic agent may be mixed and used in the pressure-sensitive adhesive composition, but a bleed out phenomenon may be generated due to the surface migration of the ionic antistatic agent. This problem may be particularly exacerbated when exposed to high temperature and high temperature and high humidity environments.

In addition, the liquid crystal cell including a metal layer such as ITO is corroded by H ₂ O and O ₂ contained in the pressure-sensitive adhesive to form metal oxides, hydroxides, and other corrosive products. These may reduce the electrical or mechanical stability of the liquid crystal display, or may cause problems in securing visibility and reliability.

In order to improve the corrosiveness of metals, there is a tendency to exclude the use of hydrogen ion generating monomers (eg, monomers having a carboxyl group) which are essentially used for improving durability of the pressure-sensitive adhesive composition.

As mentioned above, the demand for the adhesive composition excellent in antistatic property and durability is increasing recently, without using a hydrogen ion generating monomer.

In this regard, a method of using an acryl-based copolymer having increased compatibility with an ionic antistatic agent by introducing an amine group or a polyethylene glycol group while excluding a hydrogen ion generating monomer has been proposed (Korean Patent Publication No. 2009-132564). , 2011-136760).

However, this method is a situation that the effect is insufficient to improve the durability degradation due to the bleed out phenomenon.

The present invention is excellent in durability as well as antistatic properties because there is no phenomenon such as lifting, bubbles and peeling due to the surface migration of the ionic antistatic agent, and it does not contain a corrosion inhibitor component and can effectively suppress corrosion of the metal layer. The purpose is to provide a composition.

In order to achieve the above object, the present invention provides an adhesive composition containing an acrylic copolymer having a carboxyl group, and an ionic antistatic agent having an epoxy group.

The acrylic copolymer having a carboxyl group may contain an acrylic monomer of Formula 1 or Formula 2.

[Formula 1]

[Formula 2]

Preferably, the acrylic copolymer having a carboxyl group may contain a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms and an acrylic monomer of Formula 1 or Formula 2.

More preferably, the acrylic copolymer having a carboxyl group contains a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, an acrylate monomer of Formula 1 or Formula 2, and an acrylate monomer having a hydroxy group. can do.

The acryl-based monomer may contain 0.1 to 2 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms.

The ionic antistatic agent having the epoxy group includes a cation selected from the group consisting of pyridinium salt, imidazonium salt, ammonium salt, sulfonium salt and phosphonium salt containing epoxy group, fluorine-containing inorganic salt, fluorine-containing organic salt and iodine ion. It may be an ionic salt consisting of an anion selected from the group consisting of.

The ionic antistatic agent having the epoxy group may be the following Formula 3 or 4.

[Formula 3]

(Wherein R ₁ , R ₂ and R ₃ are each independently an aliphatic hydrocarbon having 1 to 12 carbon atoms)

[Formula 4]

The ionic antistatic agent having the epoxy group may be contained in an amount of 1 to 10 moles per 1 mole of the carboxylic acid of the acrylic copolymer.

Preferably, the ionic antistatic agent having the epoxy group may be contained in a ratio of 5 to 10 moles per 1 mole of the carboxylic acid of the acrylic copolymer.

The pressure-sensitive adhesive composition may further contain an ionic antistatic agent composed of cations and anions.

The pressure-sensitive adhesive composition may further contain a crosslinking agent.

The pressure-sensitive adhesive composition of the present invention does not have a phenomenon such as lifting, bubbles, and peeling due to the surface migration of the antistatic agent, which is excellent in durability and at the same time has an advantage of satisfying antistatic property.

The pressure-sensitive adhesive composition of the present invention has an advantage of effectively suppressing corrosion of the metal layer without separately containing a corrosion inhibitor component.

Therefore, the pressure-sensitive adhesive composition is expected to have high utility for anti-static applications in the fields of plastic products, especially electrical / electronic devices, which tend to generate static electricity.

The present invention improves the compatibility between the antistatic agent and the acrylic copolymer containing no acid, thereby suppressing the bleed out of the antistatic agent, thereby improving the durability, antistatic property and corrosion resistance at the same time. It is about.

Hereinafter, the present invention will be described in detail.

The adhesive composition of this invention contains the adhesive composition containing the acrylic copolymer which has a carboxyl group, and the ionic antistatic agent which has an epoxy group.

The pressure-sensitive adhesive composition of the present invention reacts with the carboxyl group of the acrylic copolymer and the epoxy group of the ionic antistatic agent to introduce an ionic functional group derived from the ionic antistatic agent into the acrylic copolymer, as shown below. The ionic functional groups introduced into the acrylic copolymer form strong ionic bonds with the ionic antistatic agent.

[Mechanism 1]

[Mechanism 2]

At this time, it is preferable that the ionic antistatic agent which has an epoxy group is contained in 1-10 mol ratio with respect to 1 mol of carboxyl groups of an acryl-type copolymer.

By the ion bonding, the bleed out phenomenon in which the antistatic agent component moves to the surface and precipitates is suppressed, and the durability is excellent. This phenomenon can be suppressed even under high temperature or high temperature / humidity environment, thereby maintaining excellent durability.

In addition, since the ionic functional group induced in the acrylic copolymer together with the ionic antistatic agent has an antistatic property, the pressure-sensitive adhesive composition of the present invention is significantly improved in performance compared to the pressure-sensitive adhesive composition using a conventional antistatic agent only.

In addition, although the acrylic copolymer of the present invention contains a carboxylic acid, since the epoxy group of the ionic antistatic agent contained in the adhesive composition reacts with the carboxylic acid, corrosion of the metal by the carboxylic acid does not occur. That is, the acrylic copolymer contains an acid component, but does not include an acid in the pressure-sensitive adhesive composition containing the acrylic copolymer.

It is preferable that the acryl-type copolymer of this invention contains the (meth) acrylate monomer which has a C4-C12 alkyl group, and the monomer which has a carboxyl group. Here, (meth) acrylate means acrylate and methacrylate.

Examples of the (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms include n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth). ) Acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate Isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and the like, among which n-butyl acrylate and 2-ethylhexyl acrylate Or mixtures thereof. These can be used individually or in mixture of 2 or more types.

Monomers, such as (meth) acrylic acid and crotonic acid, which have the said carboxyl group; Diacids such as maleic acid, itaconic acid and fumaric acid, and monoalkyl esters thereof; 3- (meth) acryloylpropionic acid; Succinic anhydride ring-opening adduct of 2-hydroxyalkyl (meth) acrylate with 2-3 carbon atoms of an alkyl group, Succinic anhydride ring opening adduct of hydroxyalkylene glycol (meth) acrylate with 2-4 carbon atoms of an alkylene group And a compound obtained by ring-opening addition of succinic anhydride to a caprolactone adduct of 2-hydroxyalkyl (meth) acrylate having 2 to 3 carbon atoms of an alkyl group, and these may be used alone or in combination of two or more thereof.

Considering the stabilization time of the surface specific resistance of the prepared pressure-sensitive adhesive composition, the monomer having a carboxyl group is preferably an acrylic monomer of the formula (1) or (2).

[Formula 1]

[Formula 2]

The stabilization time of the surface resistivity means a time when the measured surface resistivity increases and then saturates. In general, if left at room temperature for 7 days or more, the change in the surface resistivity disappears, and it is predicted that the reaction with the copolymer is completed within 7 days.

It is preferable to contain 0.1-2 weight part with respect to 100 weight part of (meth) acrylate monomers which have a C4-C12 alkyl group, and, as for the monomer which has such a carboxyl group, it is preferable that it is 0.5-1 weight part more preferably. If the content is less than 0.1 part by weight, the fixation of the antistatic agent may be insufficient and the durability may be insufficient. If the content is more than 2 parts by weight, corrosion resistance may be reduced by the remaining acid component.

The acrylic copolymer of the present invention may further contain a polymerizable monomer having a crosslinkable functional group in addition to the monomer having a carboxyl group. The polymerizable monomer having a crosslinkable functional group to be added is a component that does not generate hydrogen ions (H ⁺ ), which can impart cohesion or adhesive strength of the pressure-sensitive adhesive composition by chemical bonding to impart durability and cutting property. .

Examples of the polymerizable monomer having a crosslinkable functional group include a monomer having a hydroxy group, a monomer having an amide group, a monomer having a tertiary amine group, and the like, and these may be used alone or in combination of two or more thereof.

As a monomer which has a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, 2-hydroxypropylene glycol (meth) acrylate, hydroxyalkylene glycol having 2 to 4 carbon atoms of an alkylene group ( Meta) acrylate, 4-hydroxybutyl vinyl ether, 5-hydroxypentyl vinyl ether, 6-hydroxyhexyl vinyl ether, 7-hydroxyheptyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxynonyl Vinyl ether, 10-hydroxydecyl vinyl ether, etc. are mentioned, Among these, 4-hydroxybutyl vinyl ether is preferable.

Examples of the monomer having an amide group include (meth) acrylamide, N-isopropylacrylamide, N-tert-butylacrylamide, 3-hydroxypropyl (meth) acrylamide, 4-hydroxybutyl (meth) acrylamide, 6 -Hydroxyhexyl (meth) acrylamide, 8-hydroxyoctyl (meth) acrylamide, 2-hydroxyethylhexyl (meth) acrylamide, etc. are mentioned, Among these, (meth) acrylamide is preferable.

Monomers having a tertiary amine group include N, N- (dimethylamino) ethyl (meth) acrylate, N, N- (diethylamino) ethyl (meth) acrylate, and N, N- (dimethylamino) propyl ( Meth) acrylate, etc. are mentioned.

In consideration of the stabilization time and durability of the surface specific resistance of the prepared pressure-sensitive adhesive composition, the acrylic copolymer of the present invention may be a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, the acrylic monomer of Formula 1 or Formula 2, and a hydroxyl group. It is more preferable to contain the acrylate monomer which has.

It is preferable that the polymerizable monomer which has such a crosslinkable functional group is contained in 0.05-10 weight part with respect to 100 weight part of (meth) acrylate monomers which have a C4-C12 alkyl group, More preferably, it is 0.1-8 weight part good. If the content is less than 0.05 parts by weight, the cohesive force of the pressure-sensitive adhesive may be reduced, the durability may be lowered. If the content is more than 10 parts by weight, the adhesive strength is lowered and durability may be lowered by a high gel fraction.

In addition, the acrylic copolymer of the present invention may further contain other polymerizable monomers other than the above monomers in a range of not lowering the adhesive strength, for example, 10 parts by weight or less based on the total amount.

The production method of the copolymer is not particularly limited, and may be prepared using a method such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization, which are commonly used in the art, and solution polymerization is preferable. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control, and the like, which are usually used in the polymerization, may be used.

The acrylic copolymer preferably has a weight average molecular weight (polystyrene equivalent, Mw) measured by gel permeation chromatography (GPC) of 50,000 to 2 million, more preferably 400,000 to 2 million. If the weight average molecular weight is less than 50,000, there is a lack of cohesion between the copolymers may cause problems in adhesion durability, if the weight average molecular weight is more than 2 million may require a large amount of dilution solvent to ensure fairness during coating.

The ionic antistatic agent having an epoxy group is not particularly limited as long as it is an ionic salt composed of a cation and an anion having an epoxy group and can impart ionic conductivity to the pressure-sensitive adhesive.

Specifically, a cation selected from the group consisting of pyridinium salt, imidazonium salt, ammonium salt, sulfonium salt and phosphonium salt containing an epoxy group, and an anion selected from the group consisting of fluorine-containing inorganic salts, fluorine-containing organic salts and iodine ions It may be an ionic salt.

In consideration of the stabilization rate, heat resistance, and ease of manufacture of the double antistatic property, it is preferable to use a pyridinium salt or an imidazonium salt containing the following general formula (3) or an epoxy group as a cation.

[Formula 3]

(Wherein R ₁ , R ₂ and R ₃ are each independently aliphatic hydrocarbon having 1 to 12 carbon atoms). More preferably, R ₁ , R ₂ and R ₃ are each independently an aliphatic hydrocarbon having 1 to 4 carbon atoms, still more preferably a methyl group.

The pyridinium salt or imidazonium salt containing the epoxy group may be, for example, 1-methyl-3-glycidoxy imidazolium tetrafluoroborate of Chemical Formula 4 below. Formula 4 is Chemistry letters. It may be prepared by the method described in Vol 33, 2004, 560-561.

[Formula 4]

It is preferable that the adhesive composition of this invention contains the acryl-type copolymer containing the monomer which has a carboxyl group, and the ionic antistatic agent which used the pyridinium salt or imidazonium salt containing the said Formula (3) or an epoxy group as a cation. More preferably, the carboxyl group, the acrylate-based monomer having a hydroxy group, and the ionic antistatic agent using a pyridinium salt or an imidazonium salt containing the formula (3) or an epoxy group as a cation may be included.

The ionic antistatic agent having such an epoxy group may be contained in an amount of 1 to 10 moles, preferably 5 to 10 moles per 1 mole of the carboxylic acid of the acrylic copolymer. If the content is less than 1 molar ratio, the acid component may remain to reduce corrosion resistance. If the molar ratio exceeds 10 molar ratio, the immobilization ratio of the ionic antistatic agent may be small, which may cause a decrease in heat resistance due to bleed-out.

In addition to the ionic antistatic agent having the epoxy group, the present invention may further contain a conventional ionic antistatic agent composed of anions and cations. At this time, it is preferable to use an appropriate amount of the ionic antistatic agent added within the range that can achieve the effects of the present invention.

An ionic antistatic agent composed of an anion and a cation is not particularly limited as long as it is an ionic salt composed of an anion and a cation that can impart ionic conductivity to the pressure-sensitive adhesive.

Specifically, a cation selected from the group consisting of alkali metal salts, ammonium salts, sulfonium salts and phosphonium salts; It may be an ionic salt consisting of an anion selected from the group consisting of fluorine-containing inorganic salts, fluorine-containing organic salts and iodine ions.

The pressure-sensitive adhesive composition of the present invention may further contain a crosslinking agent.

A crosslinking agent can improve adhesiveness and durability, and can maintain the reliability and shape of an adhesive at high temperature.

The crosslinking agent may be an isocyanate type, an epoxy type, a melamine type, a peroxide type, a metal chelate type, an oxazoline type, or the like, and one or two or more kinds thereof may be used. Double isocyanate type or epoxy type is preferred.

The isocyanate type is tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate, naphthalenedi Diisocyanate compounds such as isocyanate; Diisocyanate obtained from 2 moles of an adduct obtained by reacting 3 moles of a diisocyanate compound with 1 mole of a polyhydric alcohol compound such as trimethylolpropane, an isocyanurate obtained by self-condensing 3 moles of the diisocyanate compound, and 3 moles of the diisocyanate compound And polyfunctional isocyanate compounds containing three functional groups such as biuret, triphenylmethanetriisocyanate, and methylenebistriisocyanate, in which the remaining 1 mole of diisocyanate is condensed to urea.

The epoxy-based ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol di Glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, di Glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylolpropanetriglycidyl ether, pentaerythritol poly Glycidyl ether, sorbitol polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) isocyanuric Tris (glycidoxyethyl) isocyanurate, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl-m- Xylylenediamine etc. are mentioned.

Examples of the melamine type include hexametholol melamine, hexamethoxymethyl melamine, hexabutoxymethyl melamine, and the like.

Such a crosslinking agent may be contained in an amount of 0.1 to 15 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the acrylic copolymer. If the content is less than 0.1 part by weight, the cohesive force may be reduced due to insufficient crosslinking degree, thereby impairing the adhesive durability and the cleavage property. If the content is more than 15 parts by weight, problems may occur in reducing residual stress due to excessive crosslinking reaction.

In addition to the above components, the pressure-sensitive adhesive composition is a silane coupling agent, tackifying resin, antioxidant, leveling agent, surface lubricant, dye, in order to adjust the adhesion, cohesion, viscosity, elastic modulus, glass transition temperature, etc. Additives, such as a pigment, an antifoamer, a filler, and a light stabilizer, can be further contained.

Such additives can be appropriately adjusted in a range not impairing the effects of the present invention.

In particular, the pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive for polarizing plates and a surface protective film for bonding to liquid crystal cells. In addition, it can be used as a general commercial adhesive sheet product as well as a protective film, a reflective sheet, a structural adhesive sheet, a photographic adhesive sheet, a lane marking adhesive sheet, an optical adhesive product, an adhesive for electronic parts, and the like.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Preparation Example: Acrylic Copolymer Preparation

Preparation Example 1

90 parts by weight of n-butyl acrylate (BA), 7 parts by weight of methyl acrylate (MA), 2-hydroxyethyl acrylate in a 1 L reactor equipped with a refrigeration system for reflux of nitrogen gas and for easy temperature control. HEA) 2.0 parts by weight and a monomer mixture consisting of 1 part by weight of acrylic acid (AA) was added, then 100 parts by weight of acetone as a solvent. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 62 ℃. After homogenizing the mixture, 0.07 parts by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator, and reacted for 6 hours to prepare an acrylic copolymer having a weight average molecular weight of about 1 million.

Preparation Example 2

In the same manner as in Preparation Example 1, an acrylic copolymer was prepared using 1 part by weight of carboxyethyl acrylate (CEA) instead of acrylic acid.

Preparation Example 3

The same process as in Preparation Example 1, but using an acrylic acid content of 0.2 parts by weight to prepare an acrylic copolymer.

Preparation Example 4

The same process as in Preparation Example 1, but using an acrylic acid content of 1.5 parts by weight to prepare an acrylic copolymer.

Preparation Example 5

The same procedure as in Preparation Example 1, except that 91 parts by weight of n-butyl acrylate (BA), 7 parts by weight of methyl acrylate (MA), and 2.0 parts by weight of 2-hydroxyethyl acrylate were used for the acrylic aerial. The coalescence was prepared.

Preparation Example 6

In the same manner as in Preparation Example 1, an acrylic copolymer was prepared using 1 part by weight of methoxyethyl acrylate (MEA) instead of acrylic acid.

Preparation Example 7

The same process as in Preparation Example 1, but using an acrylic acid 3 parts by weight to prepare an acrylic copolymer.

Preparation Example 8

In the same manner as in Preparation Example 1, 90 parts by weight of n-butyl acrylate (BA), 8 parts by weight of benzyl methacrylate (BzMA), 1.0 part by weight of 2-hydroxyethyl acrylate (HEA) and carboxyethyl acrylic Rate (Formula 1,

An acrylic copolymer was prepared using a monomer mixture consisting of 1 part by weight.

Preparation Example 9

The same procedure as in Preparation Example 8, except that carboxyethyl acrylate (

) Instead of

An acrylic copolymer was prepared using (Formula 2).

Preparation Example 10

In the same manner as in Preparation Example 8, an acrylic copolymer was prepared using acrylic acid instead of carboxyethyl acrylate (CEA).

To summarize the components used in Preparation Examples 1 to 10 are shown in Table 1 below.

TABLE 1

Examples 1-13 and Comparative Examples 1-3

As shown in Table 2, 0.5 parts by weight of the acrylic copolymer of the above preparation, 0.5 parts by weight of a crosslinking agent (CORONATE-L, Japan Urethane Co., Ltd.), an ionic antistatic agent having an epoxy group and a silane coupling agent (acetoacetoxypropyl trimethoxysilane) After mixing, the mixture was diluted with an organic solvent to prepare an adhesive composition.

At this time, Table 2 described an antistatic agent having an acrylic copolymer, an ionic antistatic agent and an epoxy group, and other crosslinking agents and silane coupling agents used the same components and contents.

TABLE 2

The pressure-sensitive adhesive composition prepared above was applied on a release film coated with a silicone release agent to have a thickness of 25 μm, and dried at 100 ° C. for 1 minute to form an adhesive layer.

A pressure-sensitive adhesive polarizing plate was prepared by laminating the pressure-sensitive adhesive layer prepared above on an iodine-based polarizing plate having a thickness of 185 μm. The prepared polarizing plate was stored under curing conditions at 23 ° C. and 60% RH.

Example 13

It carried out similarly to Example 1, but using the CORONATE-HXR (Japan urethane company) as a crosslinking agent instead of CORONATE-L to prepare a pressure-sensitive adhesive composition.

Test Example

The physical properties of the pressure-sensitive adhesive composition and pressure-sensitive adhesive polarizing plate prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 3 below.

1. Stabilization time for surface resistivity (Ω / □) and surface resistivity (Ω / □)

The prepared pressure-sensitive adhesive polarizing plate was measured 10 times each of three points of the pressure-sensitive adhesive layer by using a surface resistance measuring instrument (MCP-HT450, Mitsubishi Chemical Co., Ltd.), and the average value was shown.

In addition, the time when the measured value of the surface specific resistance increases and saturation is expressed as the stabilization time.

2. Adhesive durability

After peeling the release film of the polarizing plate with an adhesive and bonding the surface of an adhesive layer and Corning glass, after leaving for 300 hours at 80 degreeC (heat resistance) / 60 degreeC, 90 RH% (humidity heat resistance), the external appearance was confirmed.

<Evaluation Criteria>

Bubble and Peeling Admitted Admitted: ×

Bubble or peeling is slightly visible but polarizer performance is maintained: ○

Bubbles and Peelings Unidentified: ◎

3. Corrosion resistance of metal layer

After peeling the release film of the polarizing plate with an adhesive, after bonding the surface of an adhesive layer and an aluminum plate, it left for 250 hours in 60 degreeC and 95% RH atmosphere, and manufactured the specimen.

The adhesive layer was peeled from the said laminated body, the surface of the aluminum plate which contacted the said adhesive layer was visually observed, and the presence or absence of corrosion was evaluated.

<Evaluation Criteria>

The aluminum plate surface is not corroded at all: ◎

The surface of aluminum plate is slightly corroded, but the function of aluminum plate is maintained: ○

Surface of aluminum plate is corroded: ×

TABLE 3

As shown in Table 3, the pressure-sensitive adhesive composition of Examples 1 to 13 containing an acrylic copolymer having a carboxyl group and an ionic antistatic agent having an epoxy group according to the present invention is more durable (heat and moisture resistant) than Comparative Examples 1 to 3. It was confirmed that the antistatic property and the corrosion resistance were excellent at the same time.

Claims (11)

1. An adhesive composition containing an acrylic copolymer having a carboxyl group and an ionic antistatic agent having an epoxy group.
2. The pressure-sensitive adhesive composition of claim 1, wherein the acrylic copolymer having a carboxyl group contains an acrylic monomer of Formula 1 or Formula 2:

   [Formula 1]

   

   [Formula 2]

   
3. The pressure-sensitive adhesive composition of claim 1 or 2, wherein the acrylic copolymer having a carboxyl group contains a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms and an acrylic monomer of Formula 1 or Formula 2.
4. The acryl-based copolymer having a carboxyl group contains a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, an acrylate monomer of Formula 1 or Formula 2, and an acrylate monomer having a hydroxy group. Pressure-sensitive adhesive composition.
5. The pressure-sensitive adhesive composition of claim 2, wherein the acrylic monomer contains 0.1 to 2 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms.
6. The method of claim 1, wherein the ionic antistatic agent having an epoxy group is a cation selected from the group consisting of pyridinium salt, imidazonium salt, ammonium salt, sulfonium salt and phosphonium salt containing an epoxy group,

   Pressure-sensitive adhesive composition which is an ionic salt consisting of an anion selected from the group consisting of fluorine-containing inorganic salts, fluorine-containing organic salts and iodine ions.
7. The pressure-sensitive adhesive composition of claim 6, wherein the ionic antistatic agent having the epoxy group is represented by Formula 3 or 4.

   [Formula 3]

   

   (Wherein R ₁ , R ₂ and R ₃ are each independently an aliphatic hydrocarbon having 1 to 12 carbon atoms)

   [Formula 4]

   
8. The pressure-sensitive adhesive composition according to claim 6, wherein the ionic antistatic agent having an epoxy group is contained in an amount of 1 to 10 moles per 1 mole of the carboxylic acid of the acrylic copolymer.
9. The pressure-sensitive adhesive composition of claim 8, wherein the ionic antistatic agent having an epoxy group is contained at a ratio of 5 to 10 moles per 1 mole of the carboxylic acid of the acrylic copolymer.
10. The pressure-sensitive adhesive composition of claim 1, wherein the pressure-sensitive adhesive composition further contains an ionic antistatic agent composed of cations and anions.
11. The pressure-sensitive adhesive composition of claim 1, wherein the pressure-sensitive adhesive composition further contains a crosslinking agent.