KR102423737B1 - Adhesive composition and adhesive sheet - Google Patents

Abstract

A pressure-sensitive adhesive composition comprising a (meth)acrylic polymer having a carboxyl group and 0.005 parts by mass to 2.5 parts by mass of an alicyclic epoxy-modified silicone with respect to 100 parts by mass of the (meth)acrylic polymer.

Description

An adhesive composition and an adhesive sheet {ADHESIVE COMPOSITION AND ADHESIVE SHEET}

One embodiment of the present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.

As a display device for displaying an image, such as a liquid crystal display device and an organic electroluminescent display device, various display systems are widely used.

A liquid crystal display generally consists of a liquid crystal cell in which a liquid crystal component oriented in a predetermined direction is sandwiched between two supporting substrates, and an optical film such as a polarizing plate, a retardation plate, and a luminance increasing film. When laminating|stacking a liquid crystal cell, an optical film, or optical films, and producing a liquid crystal display device, these members are bonded together through the adhesive layer formed from an adhesive composition.

Optical films, such as a polarizing plate, are normally comprised by laminating|stacking materials with different shrinkage rates, and are easy to raise|generate a dimensional change with the change of temperature or humidity. For this reason, when the optical film bonded through the pressure-sensitive adhesive layer is exposed to a harsh environment such as a high-temperature environment or a high-temperature, high-humidity environment, the optical film is curled, and lifting or peeling occurs at the interface between the pressure-sensitive adhesive layer and the optical film or liquid crystal cell. there was a case Therefore, the adhesive composition which can form the highly durable adhesive layer which can suppress float and peeling is calculated|required.

As a method of improving the durability of the pressure-sensitive adhesive layer, a method of suppressing the dimensional change of the optical film by increasing the cohesive force of the pressure-sensitive adhesive layer has been proposed. For example, Japanese Patent Application Laid-Open No. 2011-37927 discloses that 100 parts by weight of an acrylic polymer and isocyanate as an adhesive that does not float or peel off at the bonding interface between the adherend and the pressure-sensitive adhesive layer even after being adhered to the adherend and exposed to high temperature and high humidity for a long period of time. An optical pressure-sensitive adhesive containing 5 to 50 parts by weight of a crosslinking agent is disclosed.

On the other hand, the adhesive composition which added silicone as an adhesive composition which made the durability of an adhesive layer and other physical properties compatible is proposed. For example, in Japanese Patent Application Laid-Open No. 2009-258294, a pressure-sensitive adhesive composition capable of satisfying reworkability, processability and durability is made by containing 50% by weight or more of alkyl (meth)acrylate, and has a weight average molecular weight of 1.5 million or more. A pressure-sensitive adhesive composition for an optical film comprising 0.01 to 1 parts by weight of a silane coupling agent, 0.01 to 10 parts by weight of a siloxane compound having a specific structure, and 0.01 to 5 parts by weight of a crosslinking agent with respect to (meth)acrylic polymer and 100 parts by weight of the polymer has been disclosed.

However, it is assumed that the optical film is repeatedly exposed under a high temperature environment and a low temperature environment in addition to being exposed for a long period of time in a high temperature and high humidity environment. Under the harsh environment of repeated exposure to such high-temperature and low-temperature atmospheres, as in the optical adhesive described in Japanese Patent Laid-Open No. 2011-37927, an adhesive with a high content of a crosslinking agent and increased cohesion, so-called hard-type adhesive, suppresses curl of the optical film It was not possible, and floatation or peeling occurred at the interface between the pressure-sensitive adhesive layer and the optical film or liquid crystal cell, and the durability of the pressure-sensitive adhesive layer was not sufficient.

Moreover, also in the adhesive composition for optical films of Unexamined-Japanese-Patent No. 2009-258294, the durability of an adhesive layer was not enough.

Furthermore, the size of the curl of the optical film that occurs according to temperature and humidity changes also depends on the shrinkage rate of the material constituting the optical film, and an adhesive layer that can suppress curl even for an optical film that is prone to large curl is required. .

One Embodiment of this invention is made|formed in view of the above, and makes it a subject to achieve the following objects. That is, an embodiment of the present invention provides a pressure-sensitive adhesive composition in which a pressure-sensitive adhesive layer with excellent durability is formed with difficulty in lifting or peeling at the interface between an adherend and a pressure-sensitive adhesive layer even under an environment repeatedly exposed to a high-temperature atmosphere and a low-temperature atmosphere, and a high-temperature atmosphere An object of the present invention is to provide a pressure-sensitive adhesive sheet that is difficult to cause lifting or peeling at the interface between an adherend and a pressure-sensitive adhesive layer even under an environment repeatedly exposed to a low-temperature atmosphere and has excellent durability.

The following aspects are included in the specific means for solving the said subject.

<1> A pressure-sensitive adhesive composition comprising a (meth)acrylic polymer having a carboxyl group and 0.005 parts by mass to 2.5 parts by mass of an alicyclic epoxy-modified silicone with respect to 100 parts by mass of the (meth)acrylic polymer.

<2> The pressure-sensitive adhesive composition according to <1>, further comprising 6 parts by mass to 30 parts by mass of an isocyanate compound with respect to 100 parts by mass of the (meth)acrylic polymer.

<3> The pressure-sensitive adhesive composition according to <1> or <2>, wherein the alicyclic epoxy-modified silicone has an alicyclic epoxy group in a side chain.

<4> The pressure-sensitive adhesive composition according to any one of <1> to <3>, wherein the alicyclic epoxy-modified silicone is a compound represented by the following general formula (1).

In the general formula (1), X represents a substituent represented by the following general formula (2), n is 1 or more, m is 0 or more, and m+n is less than 5.

In general formula (2), R represents a divalent organic group.

<5> The pressure-sensitive adhesive composition according to any one of <1> to <4>, wherein the (meth)acrylic polymer has an acid value of 5 mg/KOH to 50 mg/KOH.

<6> The adhesive sheet which has an adhesive layer formed from the adhesive composition in any one of <1>-<5>.

It further has a <7> optical film, The adhesive sheet as described in <6> which has the said adhesive layer on at least one surface of the said optical film.

The <8> adhesive sheet as described in <7> whose said optical film is a polarizing plate.

According to an embodiment of the present invention, even under an environment repeatedly exposed to a high temperature atmosphere and a low temperature atmosphere, lifting or peeling is unlikely to occur at the interface between the adherend and the pressure sensitive adhesive layer, and a pressure sensitive adhesive composition capable of forming a pressure sensitive adhesive layer having excellent durability, and high temperature A pressure-sensitive adhesive sheet having excellent durability is provided, which is difficult to cause lifting or peeling at the interface between an adherend and a pressure-sensitive adhesive layer even under an environment repeatedly exposed to an atmosphere and a low-temperature atmosphere.

Hereinafter, the adhesive composition and adhesive sheet of one Embodiment of this invention are demonstrated in detail.

In this specification, (meth)acrylate means at least one of acrylate and methacrylate, and (meth)acryl means at least one of acryl and methacryl.

In addition, the numerical range indicated using "~" in this specification indicates a range including the numerical values described before and after "to" as the minimum and maximum values, respectively.

<Adhesive composition>

The pressure-sensitive adhesive composition contains a (meth)acrylic polymer having a carboxyl group (hereinafter, simply referred to as a (meth)acrylic polymer), and 0.005 parts by mass to 2.5 parts by mass of an alicyclic epoxy-modified silicone based on 100 parts by mass of the (meth)acrylic polymer. do.

The pressure-sensitive adhesive composition preferably further contains 6 parts by mass to 30 parts by mass of an isocyanate compound with respect to 100 parts by mass of the (meth)acrylic polymer in addition to the (meth)acrylic polymer and the alicyclic epoxy-modified silicone.

Since the pressure-sensitive adhesive composition has the above-described configuration, it is difficult to cause lifting or peeling, and it is possible to form a pressure-sensitive adhesive layer having excellent durability.

Although the reason why the effect of one Embodiment of this invention appears is not clear, it is estimated as follows.

In one embodiment of the present invention, it is considered that the alicyclic epoxy-modified silicone and the (meth)acrylic polymer having a carboxyl group are included in the pressure-sensitive adhesive composition, so that both react to form a reactant. Silicone is known to function as a releasing component that imparts releasability, but the site derived from the alicyclic epoxy-modified silicone of a reaction product of an alicyclic epoxy-modified silicone and a (meth)acrylic polymer having a carboxy group functions as a site providing releasability. Rather, it functions as a site (adsorption site) that imparts adsorption to an adherend. Therefore, the pressure-sensitive adhesive layer formed of this pressure-sensitive adhesive composition matches the adhesive strength of the portion derived from the (meth)acrylic polymer having a carboxyl group and the adsorption property of the portion derived from the alicyclic epoxy-modified silicone. It is thought that adhesive force becomes high compared with it. As a result, it is thought that it becomes difficult to generate|occur|produce floating|lifting and peeling at the interface of a to-be-adhered body and an adhesive layer even under the harsh environment repeatedly exposed to a high-temperature atmosphere and a low-temperature atmosphere.

Moreover, the said adhesive force improvement effect is expressed because content of the alicyclic epoxy-modified silicone in an adhesive composition is a predetermined range. When the content of the alicyclic epoxy-modified silicone in the pressure-sensitive adhesive composition is small, a sufficient adhesive strength improvement effect is not obtained, and when the content of the alicyclic epoxy-modified silicone in the pressure-sensitive adhesive composition is large, it functions as a mold release component and conversely reduces the adhesive strength do.

[(meth)acrylic polymer]

The pressure-sensitive adhesive composition includes a (meth)acrylic polymer having a carboxyl group.

Since the pressure-sensitive adhesive composition contains a (meth)acrylic polymer having a carboxyl group, the carboxyl group of the (meth)acrylic polymer reacts with an alicyclic epoxy-modified silicone to be described later, so lifting or peeling occurs even under an environment repeatedly exposed to high temperature and low temperature atmospheres. A pressure-sensitive adhesive layer that is difficult to be formed can be formed.

A (meth)acrylic polymer having a carboxy group has a structural unit derived from a (meth)acrylic monomer having a carboxy group, and a structural unit derived from other monomers derived from a (meth)acrylic monomer having no reactive functional group, and You may further have the structural unit derived from the monomer which has reactive functional groups other than a carboxy group.

In addition, a "reactive functional group" means a functional group which has reactivity with the alicyclic epoxy-modified silicone or a crosslinking agent mentioned later.

Examples of the (meth)acrylic monomer having a carboxyl group include acrylic acid, methacrylic acid, ω-carboxy-polycaprolactone mono(meth)acrylate, succinate monohydroxyethyl(meth)acrylate, maleic acid monohydroxyethyl (meth) ) acrylate, monohydroxyethyl fumarate (meth)acrylate, monohydroxyethyl phthalate (meth)acrylate, 1,2-dicarboxycyclohexane monohydroxyethyl (meth)acrylate, (meth)acrylic acid dimer can be heard These may be used individually by 1 type, or may be used in combination of 2 or more type. Among them, acrylic acid is preferable from the viewpoint of having high reactivity with other monomers during the copolymerization reaction and reducing unreacted monomers.

The content rate of the structural unit derived from the (meth)acrylic monomer having a carboxyl group in the (meth)acrylic polymer is preferably 0.1% by mass to 5% by mass, and 1% by mass to 5% by mass relative to the total mass of the (meth)acrylic polymer. is more preferable, and 1 mass % - 3 mass % are still more preferable. When the content rate of the structural unit derived from the (meth)acryl monomer having a carboxyl group is 0.1 mass % or more, the reaction with the alicyclic epoxy-modified silicone described later can be effectively performed, and durability when used as an adhesive layer can be improved, and 5 mass % If it is below, it can suppress that the pot life of an adhesive composition becomes short.

It is preferable that the (meth)acrylic polymer further has a structural unit derived from the (meth)acrylic monomer which does not have a reactive functional group. As a (meth)acrylic monomer having no reactive functional group, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate , n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) ) acrylate, n-dodecyl (meth) acrylate, stearyl (meth) acrylate (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, phenoxyethyl (meth) acrylate and benzyl (meth) acrylate ) and (meth)acrylates having aromatic ring groups such as acrylates. These may be used individually by 1 type, or may be used in combination of 2 or more type.

Among these, alkyl (meth)acrylate and phenoxyethyl (meth)acrylate having an alkyl group having 1 to 4 carbon atoms are preferable from the viewpoint of easy adjustment of the cohesive force and adhesive force when the pressure-sensitive adhesive layer is used. The alkyl acrylate and phenoxyethyl acrylate which have a phosphorus alkyl group are more preferable.

In addition, when using n-butyl acrylate and a (meth)acrylic monomer having no other reactive functional group together, using n-butyl acrylate as a main component to use methyl acrylate and n-butyl acrylate together, n-butyl Using acrylate as a main component and using methyl acrylate, phenoxyethyl acrylate and n-butyl acrylate together, or using n-butyl acrylate as a main component, t-butyl acrylate and n-butyl acrylate It is more preferable to use together.

The content rate of the structural unit derived from the (meth)acrylic monomer that does not have a reactive functional group in the (meth)acrylic polymer is preferably 50% by mass or more, more preferably 75% by mass or more, based on the total mass of the (meth)acrylic polymer, , more preferably 90 mass % or more.

In addition, when n-butyl acrylate (BA) is used as a (meth)acrylic monomer having no reactive functional group, the content rate of the structural unit derived from BA in the (meth)acrylic polymer is based on the total mass of the (meth)acrylic polymer. It is preferable that they are 75 mass % - 99 mass %, It is more preferable that they are 80 mass % - 98 mass %, It is still more preferable that they are 85 mass % - 96 mass %.

When using methyl acrylate (MA) and/or phenoxyethyl acrylate (PHEA) and n-butyl acrylate (BA) as a (meth)acrylic monomer having no reactive functional group, MA and/or PHEA for BA It is preferable that it is 0.01-1, as for content mass ratio ((MA+PHEA)/BA), it is more preferable that it is 0.1-1, It is still more preferable that it is 0.1-0.7. If the content mass ratio of MA and/or PHEA to BA is 0.01 or more, the polarity of the (meth)acrylic polymer increases, and it becomes easy to mix even if a large amount of isocyanate-based compound is included in the pressure-sensitive adhesive composition. It tends to be easy to maintain (tackness).

The total content of the structural units derived from MA and/or PHEA and BA in the (meth)acrylic polymer is preferably 95% by mass to 99.9% by mass, 95% by mass to 99% by mass relative to the total mass of the (meth)acrylic polymer. is more preferable, and 95 mass % - 98 mass % are still more preferable.

When t-butyl acrylate (t-BA) and n-butyl acrylate (BA) are used together as a (meth)acrylic monomer having no reactive functional group, the content mass ratio of t-BA to BA (t-BA/BA) It is preferable that it is 0.01-1, It is more preferable that it is 0.01-0.5, It is more preferable that it is 0.01-0.1. If the content mass ratio of t-BA to BA is 0.01 or more, the elasticity of the (meth)acrylic polymer increases and the cohesive force when it is used as an adhesive layer can be improved. There is this.

The total content of structural units derived from t-BA and BA in the (meth)acrylic polymer is preferably 95% by mass to 99.9% by mass, more preferably 95% by mass to 99% by mass relative to the total mass of the (meth)acrylic polymer. It is preferable, and 95 mass % - 98 mass % are still more preferable.

The (meth)acrylic polymer may further have a structural unit derived from a monomer having a reactive functional group other than a carboxy group. As a monomer having a reactive functional group other than a carboxy group, a monomer having a hydroxyl group such as 2-hydroxyethyl acrylate (2HEA) and 4-hydroxybutyl acrylate, a monomer having an amide group such as N,N-dimethylacrylamide, 4- and monomers having an epoxy group such as hydroxybutyl acrylate glycidyl ether and glycidyl methacrylate, and from the viewpoint of cohesive force, a monomer having a hydroxyl group is preferable, and 2-hydroxyethyl acrylate is particularly preferable. do.

The total content of structural units derived from a monomer having a reactive functional group other than a carboxyl group in the (meth)acrylic polymer is preferably 2% by mass or less with respect to the total mass of the (meth)acrylic polymer, more preferably 0.5% by mass or less, It is more preferable that it is 0.2 mass % or less.

A particularly preferred (meth)acrylic polymer is a copolymer comprising at least structural units derived from acrylic acid (AA), n-butyl acrylate (BA), methyl acrylate (MA) and/or phenoxyethyl acrylate (PHEA). And a copolymer comprising at least a structural unit derived from acrylic acid, n-butyl acrylate and t-butyl acrylate (t-BA), specifically a copolymer of AA/BA/MA, AA/BA/MA/2HEA Copolymer of AA/BA/PHEA, Copolymer of AA/BA/2HEA/PHEA, Copolymer of AA/BA/MA/PHEA, Copolymer of AA/BA/MA/2HEA/PHEA, AA/ The copolymer of BA/t-BA and the copolymer of AA/BA/t-BA/2HEA are mentioned.

The acid value of the (meth)acrylic polymer is preferably 5 mg/KOH to 50 mg/KOH, more preferably 5 mg/KOH to 40 mg/KOH, and still more preferably 10 mg/KOH to 40 mg/KOH.

When the acid value of the (meth)acrylic polymer is 5 mg/KOH or more, the reaction with the alicyclic epoxy-modified silicone described later can be effectively performed to improve durability when used as an adhesive layer, and when it is 50 mg/KOH or less, the pot life of the adhesive composition shortening can be suppressed.

In the present specification, the acid value of the (meth)acrylic polymer is a value measured by the following method. That is, it measures according to the following (1)-(4).

(1) About 5 g of (meth)acrylic polymer is taken in an Erlenmeyer flask, the solvent is removed at room temperature and reduced pressure, and then dried with a hot air dryer at 105° C. as a polymer sample.

(2) A polymer sample is dissolved in 100 ml of a mixed solvent (volume ratio: toluene/ethanol = 50/50) to obtain a sample solution.

(3) The titration of a sample solution is performed under the following conditions, and the titration amount is measured.

Titration solution: ethanolic potassium hydroxide solution (0.1N, manufactured by Wako Pure Chemical Industries, Ltd., for volume analysis)

Indicator: phenolphthalein

(4) The acid value (A) is calculated by the following formula.

A={(Y-X)×f×5.61}/M

A; acid

Y; Titration of sample solution (ml)

X; Appropriate amount (ml) of a solution of only 100 ml of mixed solvent (not including polymer sample)

f; Factor of titration solution

M; Mass of polymer sample (g)

The weight average molecular weight (Mw) of the (meth)acrylic polymer is preferably 300,000 to 2,000,000, more preferably 500,000 to 2,000,000, and still more preferably 700,000 to 1,800,000 from the viewpoint of durability when used as an adhesive layer.

Moreover, the dispersion degree (Mw/Mn) in particular of a (meth)acrylic-type polymer is not restrict|limited, For example, it can be set as 2-20, 3-15 are preferable and 4-9 are more preferable. When a dispersion degree is the said range, the wettability to a to-be-adhered body is favorable, the adhesive layer which has sufficient cohesive force is obtained, and durability at the time of setting it as an adhesive layer can be improved.

In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the (meth)acrylic polymer are values measured by the following method. That is, it is measured according to the following (1)-(3).

(1) A (meth)acrylic polymer solution is coated on a release film and dried at 100° C. for 2 minutes to obtain a film-like (meth)acrylic polymer.

(2) The film-like (meth)acrylic polymer obtained in the above (1) is dissolved with tetrahydrofuran so that the solid content is 0.2% by mass.

(3) The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth)acrylic polymer are measured using gel permeation chromatography (GPC) under the following conditions.

<condition>

GPC: HLC-8220 GPC [manufactured by Toso Corporation]

·Column: TSK-GEL GMHXL (4 pcs.)

· Mobile phase solvent: tetrahydrofuran

・Standard sample: standard polystyrene

Flow rate: 0.6ml/min

·Column temperature: 40℃

The range of -50 degreeC - -30 degreeC is preferable, and, as for the glass transition temperature (Tg) of a (meth)acrylic-type polymer, the range of -49 degreeC - -40 degreeC is more preferable. When Tg is -50 degreeC or more, the elastic modulus at the time of setting it as an adhesive layer can be adjusted in a suitable range, and it is excellent in durability and suppression of light leakage. Moreover, it is excellent in adhesiveness and bonding property, without impairing the viscosity at the time of setting it as an adhesive layer extremely as Tg is -30 degrees C or less.

In addition, light leakage in the present specification refers to a phenomenon in which light leaks from the periphery of the screen of the display device due to the occurrence of birefringence in the optical film or the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer formed from the resin composition is used in a display device or the like. In addition, "light leakage" is distinguished from "lifting" or "peeling" in which the pressure-sensitive adhesive layer is separated from the adherend.

In the present specification, the glass transition temperature (Tg) of the (meth)acrylic polymer is a molar average glass transition temperature obtained by the following calculation. Tg ₁ , Tg ₂ , . … and Tg _n is monomer 1, monomer 2, . … and the glass transition temperature of each homopolymer of the monomer n, which is calculated in terms of absolute temperature (K). m ₁ , m ₂ , … … and m _n is the mole fraction of each monomer.

In addition, although absolute temperature (K) is used for calculation of a glass transition temperature, when describing a glass transition temperature in this specification, Celsius temperature (degreeC) may be used.

-Calculation formula for glass transition temperature (Tg)-

In addition, the "glass transition temperature (Tg) of a homopolymer" referred to herein is a differential scanning calorimetry (DSC) (manufactured by Seiko Instruments Co., Ltd., EXSTAR6000) in a nitrogen stream of 10 mg of a measurement sample, a temperature increase rate of 10° C./min. The inflection point of the DSC curve obtained by performing the measurement was taken as the glass transition temperature (Tg) of the homopolymer.

70 mass % - 99 mass % are preferable with respect to the total solid of an adhesive composition, and, as for the content rate of the (meth)acrylic-type polymer in an adhesive composition, 75 mass % - 95 mass % are more preferable. When the content of the (meth)acrylic polymer is within the above range, hardness is imparted to the pressure-sensitive adhesive layer to suppress the generation of stress and effectively suppress the occurrence of light leakage.

The polymerization method in particular of a (meth)acrylic-type polymer is not restrict|limited, Usually, it can select suitably from the polymerization method used. As a polymerization method, solution polymerization, emulsion polymerization, suspension polymerization, etc. are mentioned. Among them, solution polymerization is preferable from the viewpoint that the (meth)acrylic polymer can be easily produced.

Solution polymerization is generally carried out by putting a predetermined organic solvent, a monomer, a polymerization initiator, a catalyst and, if necessary, a chain transfer agent in a polymerization tank, and heating and reacting for several hours while stirring in a nitrogen stream or under reflux of the organic solvent. It does not restrict|limit especially as said polymerization initiator, For example, an azo compound can be used.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth)acrylic polymer can be adjusted to a desired molecular weight by adjusting the reaction temperature, reaction time, amount of organic solvent, and type and amount of catalyst.

[alicyclic epoxy-modified silicone]

The pressure-sensitive adhesive composition contains 0.005 parts by mass to 2.5 parts by mass of the alicyclic epoxy-modified silicone with respect to 100 parts by mass of the (meth)acrylic polymer.

Conventionally, silicone is often used in the pressure-sensitive adhesive composition for the purpose of suppressing adhesive force by imparting releasability. However, the present inventors made the pressure-sensitive adhesive composition comprising an alicyclic epoxy-modified silicone and a (meth)acrylic polymer having a carboxyl group, so that the portion derived from the alicyclic epoxy-modified silicone of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is adsorbed to the adherend. was found to function as a part.

The said effect is expressed when a specific amount of alicyclic epoxy-modified silicone is contained in an adhesive composition.

If the content of the alicyclic epoxy-modified silicone is less than 0.005 parts by mass, the function as an adsorption site is not sufficient, and the durability when the pressure-sensitive adhesive layer is used is inferior. Moreover, since it functions as a mold release component when content of an alicyclic epoxy-modified silicone exceeds 2.5 mass parts, the adhesive force at the time of setting it as an adhesive layer becomes low and durability is inferior.

0.01 mass parts - 1.5 mass parts are preferable with respect to 100 mass parts of (meth)acrylic-type polymers from a durability viewpoint at the time of setting it as an adhesive layer, and, as for content of the alicyclic epoxy-modified silicone in an adhesive composition, 0.05 mass parts - 1.0 mass parts are more preferable do.

Examples of the structure of the alicyclic epoxy-modified silicone include a structure having an alicyclic epoxy group in a side chain, a structure having an alicyclic epoxy group at both terminals, and a structure having an alicyclic epoxy group at one terminal.

As an alicyclic epoxy group, an epoxycyclohexyl group is mentioned, for example. These alicyclic epoxy groups may couple|bond with silicone (siloxane skeleton) via a coupling group.

It is preferable that it has an alicyclic epoxy group in a side chain from a durability viewpoint at the time of setting it as an adhesive layer, and, as for an alicyclic epoxy-modified silicone, it is more preferable that it is a compound represented by following General formula (1).

In general formula (1), n is 1 or more, m is 0 or more, and m+n is less than 5. Among them, n is preferably 1 or more and less than 5, m is preferably 0 or more and less than 4, further, n is preferably 1 or more and 4 or less, m is preferably 0 or more and 3 or less, and particularly n is 1, , m is preferably 3.

When m+n is less than 5, the alicyclic epoxy-modified silicone does not take a helical structure, and the surface free energy is higher than that of the alicyclic epoxy-modified silicone that takes a helical structure, so a pressure-sensitive adhesive layer with strong adsorption to the adherend can be formed. . As a result, the adhesive force of an adhesive layer improves more and durability improves.

In the general formula (1), X represents a substituent represented by the following general formula (2).

In general formula (2), R represents a divalent organic group.

As the divalent organic group represented by R, an alkylene group having 1 to 10 carbon atoms is preferable, an alkylene group having 1 to 5 carbon atoms is more preferable, and an alkylene group having 1 to 3 carbon atoms is still more preferable. Examples of the alkylene group having 1 to 10 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, a butylene group, an isobutylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, and a decyl group. Callengi can be mentioned. Especially, a C1-C3 alkylene group, such as a methylene group, an ethylene group, and n-propylene group, is preferable.

As the alicyclic epoxy-modified silicone, commercially available commercially available products may be used. Examples of commercially available products include “X-22-2046”, “KF-102”, “X-22-169AS” and “X-22-169AS” manufactured by Shin-Etsu Chemical. "X-22-169B" etc. are mentioned. Among these, "X-22-2046" and "KF-102" which have an alicyclic epoxy group in a side chain are preferable.

[Isocyanate-based compound]

It is preferable that an adhesive composition contains at least 1 sort(s) of an isocyanate type compound as a crosslinking agent.

When the pressure-sensitive adhesive composition includes the isocyanate compound, the (meth)acrylic polymer having a carboxyl group and the isocyanate compound undergo a crosslinking reaction to form a pressure-sensitive adhesive layer with more improved durability.

Content of an isocyanate type compound is not specifically limited. The content of the isocyanate compound is preferably from 6 parts by mass to 30 parts by mass, more preferably from 10 parts by mass to 30 parts by mass, with respect to 100 parts by mass of the (meth)acrylic polymer from the viewpoint of durability and light leakage suppression when the pressure-sensitive adhesive layer is used. , 10 parts by mass to 20 parts by mass are more preferable.

When content of an isocyanate type compound is 6 mass parts or more with respect to 100 mass parts of (meth)acrylic-type polymers, it is excellent in durability at the time of setting it as an adhesive layer, and can prevent generation|occurrence|production of light leakage compared to the past. When the content of the isocyanate-based compound is 30 parts by mass or less, foaming due to carbon dioxide generated in the reaction of isocyanate is suppressed, and the appearance is good. Moreover, when content of an isocyanate type compound is increased, there exists a tendency for adhesiveness at the time of setting it as an adhesive layer to fall.

As an isocyanate type compound, a tolylene diisocyanate type compound is mentioned suitably, for example. As a tolylene diisocyanate type compound, the adduct body of polyols, such as a dimer or trimer of tolylene diisocyanate, or tolylene diisocyanate and trimethylol propane, etc. are mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more type.

As the tolylene diisocyanate-based compound, a commercially available product may be used, and as an example of a commercially available product, the trade names of Sumitomo Bayer Urethane Co., Ltd. products are "Desmodule IL1451CN", "Desmodule ILBA", "Desmodule HL", "Smidul" FL-2", "Smidul FL-3" and "SBU Isocyanate 0817", Nippon Polyurethane Industrial Co., Ltd. product names "Colonate L", "Colonate 2030", "Colonate 2037" and SAPICI's products trade names of "Polurene KC" and "Polurene HR" are mentioned. Especially, "colonate L" is preferable.

[Other additives]

The pressure-sensitive adhesive composition may contain other additives as necessary in addition to the alicyclic epoxy-modified silicone and the isocyanate compound.

Examples of other additives include crosslinking agents other than isocyanate-based compounds, silane coupling agents, solvents, weathering stabilizers such as ultraviolet absorbers, tachifiers, plasticizers, softeners, dyes, pigments, and inorganic fillers. When an adhesive composition contains another additive, the content can be suitably selected in the range which does not impair the effect of one Embodiment of this invention.

(Crosslinking agents other than isocyanate compounds)

The pressure-sensitive adhesive composition may further contain a crosslinking agent (eg, an epoxy compound) in addition to the isocyanate-based compound described above. When the pressure-sensitive adhesive composition contains an epoxy-based compound, it is easy to adjust the cohesive force when the pressure-sensitive adhesive layer is used, and even under a harsh environment, lifting or peeling does not occur at the interface between the adherend and the pressure-sensitive adhesive layer, and a more durable pressure-sensitive adhesive layer is formed. can do.

Examples of the epoxy compound include 1,3-bis(N,N-glycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, and the like. .

As the epoxy compound, commercially available products may be used, and Mitsubishi Gas Chemical Co., Ltd. trade names such as “TETRAD-X” and “TETRAD-C” can be suitably used as examples of the commercially available products.

As for content in the adhesive composition of an epoxy-type compound, the range of 0.001 mass part - 0.1 mass part is preferable with respect to 100 mass parts of (meth)acrylic-type polymers. When content of an epoxy compound is in the said range, it is advantageous at the point which can control the cohesion force at the time of setting it as an adhesive layer, and can suppress generation|occurrence|production of the float and peeling in a harsh environment.

(Silane coupling agent)

The adhesive composition may contain the silane coupling agent. When an adhesive composition contains a silane coupling agent, durability at the time of setting it as an adhesive layer can be improved.

As the silane coupling agent, for example, a silane compound containing a polymerizable unsaturated group such as vinyltrimethoxysilane, vinyltriethoxysilane and 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, 3 -silane-based compounds containing thiol groups such as mercaptopropyl triethoxysilane and 3-mercaptopropyl dimethoxymethylsilane, 3-glycidoxypropyl trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl Epoxy group-containing silane compounds such as trimethoxysilane, 3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane and N-(2-aminoethyl)-3-amino and amino group-containing silane compounds such as propylmethyldimethoxysilane and tris-(3-trimethoxysilylpropyl)isocyanurate. These may be used individually by 1 type, or may be used in combination of 2 or more type.

A commercially available silane coupling agent may be used, and examples of the commercially available products include “KBM-803”, “KBM-802”, “X-41-1810”, and “X-41-” manufactured by Shin-Etsu Chemical Co., Ltd. 1805", "X-41-1818", etc. Silane coupling agent having a thiol group, Shin-Etsu Chemical Co., Ltd. product name "KBM-403", "KBM-303", "KBM-402", "KBE-402" ', a silane coupling agent having an epoxy group such as "KBE-403" can be used suitably.

As for content of the silane coupling agent in an adhesive composition, 0.01 mass part - 2.0 mass parts are preferable with respect to 100 mass parts of (meth)acrylic-type polymers. If content of a silane coupling agent is in the said range, durability at the time of setting it as an adhesive layer can be improved more.

As a use of an adhesive composition, the adhesive layer used for bonding of the optical film in a liquid crystal display device etc. is suitable, for example. That is, this pressure-sensitive adhesive layer is suitable for bonding of optical films such as polarizing plate, retardation plate, antireflection film, viewing angle magnifying film, and luminance increasing film, and bonding of the above-mentioned optical film and liquid crystal cell, glass substrate, protective film, etc. It can be used conveniently, and it can use especially suitably for bonding of a polarizing plate and a liquid crystal cell.

<Adhesive sheet>

The adhesive sheet has an adhesive layer formed from the adhesive composition of one Embodiment of this invention mentioned above. The pressure-sensitive adhesive layer is less prone to lifting or peeling at the interface with the adherend even under an environment repeatedly exposed to a high-temperature atmosphere and a low-temperature atmosphere, and has excellent durability.

In addition, the pressure-sensitive adhesive sheet preferably has a pressure-sensitive adhesive layer including a cross-linked structure formed by cross-linking the pressure-sensitive adhesive composition of one embodiment of the present invention described above. Durability can be improved because an adhesive layer contains a crosslinked structure.

The thickness in particular of an adhesive layer in an adhesive sheet is not restrict|limited, According to a use or required performance, it can select suitably. As thickness of an adhesive layer, the range of 1 micrometer - 100 micrometers is mentioned, for example.

The pressure-sensitive adhesive layer preferably has high transparency, specifically, for example, a total light transmittance in a visible light wavelength region (JIS K 7361 (1997)) of 85% or more, and more preferably 90% or more.

Less than 2.0 % is preferable, as for the haze (HAZE) of an adhesive layer (JIS K 7136 (2000)), less than 1.0 % is more preferable, and its 0.5 % or less is still more preferable.

As the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet (base material type) not having a base material (base material) may be used, and the pressure-sensitive adhesive sheet (you-base material) having an pressure-sensitive adhesive layer on at least one surface of the base material (eg, optical film) type) as well.

The exposed pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet may be protected by a release film.

The release film is not particularly limited as long as it can be easily peeled off the pressure-sensitive adhesive layer, and for example, a resin film (for example, polyethylene) that has been subjected to an easy peeling treatment on at least one surface using a release treatment agent. Polyester films, such as a terephthalate (PET)) are mentioned. As a peeling agent, a fluororesin, paraffin wax, silicone, and a long-chain alkyl group compound are mentioned, for example.

The release film protects the surface of the pressure-sensitive adhesive layer until the pressure-sensitive adhesive sheet is put to practical use and is peeled off during use.

The pressure-sensitive adhesive sheet can be produced by, for example, applying the pressure-sensitive adhesive composition of one embodiment of the present invention to a release film or a base material, drying it, and forming a pressure-sensitive adhesive layer by causing a crosslinking reaction if necessary. A crosslinking agent may be previously included in an adhesive composition, and may be mixed with an adhesive composition before application|coating.

A base material type pressure-sensitive adhesive sheet is, for example, coated with a pressure-sensitive adhesive composition on the release-treated surface of the release film and dried to form a layer made of the pressure-sensitive adhesive composition. A peeling film can be overlapped so that a peeling process surface may contact|connect, and it can produce with the method of forming an adhesive layer by raising a crosslinking reaction as needed.

The u-base material type adhesive sheet may be produced by the method of apply|coating an adhesive composition to a base material (for example, an optical film), and may be produced by the method of apply|coating an adhesive composition to a peeling film. In the latter method, for example, the pressure-sensitive adhesive composition is applied to the release-treated surface of the release film, dried to form a layer made of the pressure-sensitive adhesive composition, and the base material is adhered to the exposed pressure-sensitive adhesive surface of the obtained layer that is not in contact with the release film. A method of forming a pressure-sensitive adhesive layer by combining the mixture and causing a crosslinking reaction as necessary is exemplified, whereby the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is provided on one side of the base material can be produced.

It is preferable to use an optical film as the base material of the u-base material type adhesive sheet. As an optical film, the optical film used for a liquid crystal display device is mentioned, for example. Specifically, as an optical film, optical films, such as a polarizing plate, retardation plate, an antireflection film, a viewing angle expansion film, and a brightness increasing film, can be used, and a polarizing plate can be used especially suitably.

A polarizing plate should just have a polarizer at least, for example, the polarizing plate which has a protective film on one side of a polarizer, or a polarizing plate which has a protective film on both surfaces of a polarizer can be used. As a polarizer of a polarizing plate, a polyvinyl alcohol (PVA) film is used, for example, and a triacetyl cellulose (TAC) film etc. are used as a protective film of a polarizer, for example.

As a method of applying the pressure-sensitive adhesive composition to the release film and the base material, a known method using a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, and the like is mentioned.

An adhesive sheet can be used suitably for bonding, such as an optical film of a liquid crystal display device. That is, the adhesive sheet is suitable for bonding of optical films such as, for example, a polarizing plate, retardation plate, antireflection film, viewing angle expanding film, and luminance increasing film, and bonding of the optical film and liquid crystal cell, glass substrate, protective film, etc. Available.

Examples of the pressure-sensitive adhesive sheet include a pressure-sensitive adhesive sheet having a structure (release film/adhesive layer/release film) in which a release film is laminated on both sides of an adhesive layer, an optical film on one side of the pressure-sensitive adhesive layer, and a release film on the other side of the pressure-sensitive adhesive layer. The adhesive sheet provided with (optical film / adhesive layer / peeling film) is mentioned.

Example

Hereinafter, one embodiment of the present invention will be described in more detail with reference to examples, but one embodiment of the present invention is not limited to the following examples unless the spirit is exceeded. In addition, unless otherwise indicated, "part" is a mass basis.

<Production of (meth)acrylic polymer>

[Production Example: Resin A]

88.6 parts of n-butyl acrylate (BA), 9.5 parts of methyl acrylate (MA), 1.7 parts of acrylic acid (AA), 2-hydroxyethyl acrylate in a reactor equipped with a thermometer, a stirrer, a nitrogen inlet pipe and a reflux cooling pipe (2HEA) 0.2 parts, ethyl acetate (EAc) 110 parts, and azobisdimethylvaleronitrile (ABVN) 0.1 part were put and mixed, and the inside of the reactor was substituted with nitrogen. Thereafter, the mixture in the reactor was heated to 65° C. while stirring and maintained for 8 hours for polymerization reaction. After completion of the polymerization reaction, the reaction mixture was adjusted using ethyl acetate so that the solid content was 23.0% by mass. In this way, a solution of a BA/MA/AA/2HEA copolymer (resin A) was obtained.

When the weight average molecular weight (Mw) and number average molecular weight (Mn) of the obtained resin A were measured under the conditions described above using gel permeation chromatography (GPC), the weight average molecular weight (Mw) was 1,000,000 and the molecular weight distribution (Mw) /Mn) was 5.6. Moreover, when the acid value of the obtained resin A was measured by the method mentioned above, it was 15 mg/KOH.

[Production Example: Resin B to Resin E]

In the production example of Resin A, except that the type and ratio of the monomer used for the synthesis of the copolymer was changed as shown in Table 1 below, in the same manner as in Resin A, solutions of Resin B to Resin E (solid content 23.0% by mass) were obtained, respectively. .

Moreover, about each obtained copolymer, it carried out similarly to resin A, and performed the measurement of Mw, Mn, and an acid value. The results are shown in Table 1 below.

In Table 1, "PHEA" represents phenoxyethyl acrylate, and "t-BA" represents t-butyl acrylate.

(Example 1)

<Preparation of adhesive composition>

As a (meth)acrylic polymer, 230 parts (solid content: 100.0 parts) of the solution of Resin A obtained in Production Example above, and 18.7 parts of Colonate L as an isocyanate-based compound (Nippon Polyurethane Industrial Co., Ltd., tolylene diisocyanate) and trimethylolpropane adduct, active ingredient: 14.0 parts), and 0.05 parts of X-22-2046 as an alicyclic epoxy-modified silicone (product of Shin-Etsu Chemical Co., Ltd., active ingredient: 0.05 parts), silane As a coupling agent (manufactured by SC), 0.1 parts of KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyl trimethoxysilane, active ingredient: 0.1 parts) were sufficiently stirred and mixed to obtain a pressure-sensitive adhesive composition.

<Production of adhesive sheet sample>

The pressure-sensitive adhesive composition obtained above was applied to the easily peelable surface of a peeling film (Fujimori Kogyo Co., Ltd., 100E-0010N023) subjected to an easy peeling treatment with a silicone peeling agent so that the application amount after drying was 25 g/m 2 . Next, it was dried using a hot air circulation dryer at 100° C. for 90 seconds to form a pressure-sensitive adhesive layer on the release film. Then, one side of the polarizing plate of triacetyl cellulose (TAC)/polyvinyl alcohol (PVA)/TAC structure and the pressure-sensitive adhesive layer on the release film were overlaid and pressed through a pressure nip roll. After compression, autoclave treatment (50° C., 5 kg/cm 2 , 20 minutes) was performed, and cured for 24 hours under the conditions of 23° C. and 65% RH to prepare a pressure-sensitive adhesive sheet sample having a laminated structure of release film/adhesive layer/polarizing plate did.

<Evaluation>

Various evaluations shown below were performed about the adhesive sheet sample obtained above. The results are shown in Table 2.

[Light leakage evaluation]

The pressure-sensitive adhesive sheet sample obtained above was cut into a size of 234 mm x 415 mm (long side) so that the long side was 45° with respect to the absorption axis of the polarizing plate to obtain a test piece (18.5 inches). Two of these test pieces were prepared, and the peeling film was peeled off, respectively. A sample for light leakage evaluation was prepared by affixing two test pieces with the adhesive layer exposed on both sides of the twisted nematic (TN) type liquid crystal panel using a laminator so that the absorption axis of each test piece was orthogonal to each other.

The obtained sample for light leakage evaluation was autoclaved for 20 minutes under conditions of 50° C., 5 kg/cm 2 (490 kPa), and then placed at 23° C. and 50% RH for 24 hours. Thereafter, the sample for light leakage evaluation was placed under an environment of 70° C. and 10% RH or less for 168 hours.

Thereafter, the light leakage condition was visually observed by applying uniform light to the sample for light leakage evaluation under an environment of 23° C. and 50% RH using a uniform light source.

-Evaluation standard-

A: Almost no light leakage was observed.

B: Although light leakage was slightly confirmed, it was in a practically acceptable range.

C: Light leakage was remarkably confirmed and was in a practically unacceptable range.

[Durability Evaluation]

(Production of samples for durability evaluation)

The adhesive sheet sample obtained above was cut into a size of 88 mm x 156 mm (long side) so that the long side was 45° with respect to the absorption axis of the polarizing plate to obtain a test piece (7.0 inches). The peeling film of this test piece was peeled off and the exposed adhesive layer and one side of an alkali-free glass plate (Corning Co., Ltd., #1737) having a thickness of 0.7 mm were overlapped in contact with each other, and the test piece and the glass plate were affixed using a laminator, and the sample for durability evaluation was done with

(Dry environment)

The samples for durability evaluation were autoclaved for 20 minutes under conditions of 50° C. and 5 kg/cm 2 , and then placed under an environment of 23° C. and 65% RH for 24 hours. Thereafter, the sample for durability evaluation was placed in an environment of 80°C and 10% RH or less (under a high-temperature drying environment) for 500 hours. After 500 hours, the state of the sample for durability evaluation was visually observed and evaluated according to the following evaluation criteria.

-Evaluation standard-

A: No floating or peeling was observed in the sample.

B: Although floating or peeling was seen slightly in the sample, it was in a practically acceptable range.

C: The floating|lifting and peeling of a sample were remarkable and it was a practically unacceptable range.

(Wet environment)

The samples for durability evaluation were autoclaved for 20 minutes under conditions of 50° C. and 5 kg/cm 2 , and then placed under an environment of 23° C. and 65% RH for 24 hours. Thereafter, the sample for durability evaluation was placed in an environment of 60°C and 90% RH (under a high-temperature, high-humidity environment) for 500 hours. After 500 hours, the state of the sample for durability evaluation was visually observed and evaluated according to the following evaluation criteria.

-Evaluation standard-

A: No floating or peeling was observed in the sample.

B: Although floating or peeling was seen slightly in the sample, it was in a practically acceptable range.

C: The floating|lifting and peeling of a sample were remarkable and it was a practically unacceptable range.

(H/S)

The samples for durability evaluation were autoclaved for 20 minutes under conditions of 50° C. and 5 kg/cm 2 , and then placed under an environment of 23° C. and 65% RH for 24 hours. Then, 300 cycles of a cycle (heat shock cycle; H/S cycle) left at -40°C for 0.5 hour and then left at 85°C for 0.5 hour using a cold/heat shock device (TSA-301L-W, manufactured by SPEC) After performing, the state of the sample for durability evaluation was visually observed and evaluated according to the following evaluation criteria.

-Evaluation standard-

A: No floating or peeling was observed in the sample.

B: Although floating or peeling was seen slightly in the sample, it was in a practically acceptable range.

C: The floating|lifting and peeling of a sample were remarkable and it was a practically unacceptable range.

(Example 2 - Example 13, Comparative Example 1 - Comparative Example 10)

Except having changed the adhesive composition as shown in following Table 2 in Example 1, it carried out similarly to Example 1, produced the adhesive composition, and evaluated similarly to Example 1. An evaluation result is shown in Table 2. In addition, Comparative Example 1 does not contain silicone in the pressure-sensitive adhesive composition.

The description in Table 2 is described below.

X-22-2046: alicyclic epoxy-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.) (compound represented by general formula (1))

X-22-343: Epoxy-modified silicone that does not contain a substituent represented by the general formula (2) (manufactured by Shin-Etsu Chemical Co., Ltd.)

X-22-163C: Epoxy-modified silicone that does not contain a substituent represented by the general formula (2) (manufactured by Shin-Etsu Chemical Co., Ltd.)

PAM-E: Amine-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.)

KF-2004: Mercapto-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd.)

KMB-403: Silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)

As shown in Table 2, it turns out that the generation|occurrence|production of a float or peeling is suppressed and it is excellent in durability irrespective of "Dry", "Wet", and "H/S" in the Example.

It turns out that the evaluation result of "H/S" is bad and durability is inferior in the system which does not contain an alicyclic epoxy-modified silicone like Comparative Example 1 and Comparative Example 3 - Comparative Example 8.

In a system using a (meth)acrylic polymer that does not have a carboxyl group as in Comparative Example 2, it can be seen that all evaluation results of “Dry”, “Wet” and “H/S” are poor and durability is poor.

As in Comparative Example 9, when the content of the alicyclic epoxy-modified silicone is less than 0.005 parts by mass, it turns out that the evaluation result of "H/S" is bad and durability is inferior.

As in Comparative Example 10, when the content of the alicyclic epoxy-modified silicone exceeds 2.5 parts by mass, it turns out that the evaluation result of "Wet" and "H/S" is bad and durability is inferior.

Claims (8)

A (meth)acrylic polymer having a carboxyl group,
0.005 parts by mass to 2.5 parts by mass of alicyclic epoxy-modified silicone with respect to 100 parts by mass of the (meth)acrylic polymer,
The alicyclic epoxy-modified silicone pressure-sensitive adhesive composition is a compound represented by the following general formula (1):
[Formula 1]

General formula (1)
In general formula (1), X represents the substituent shown by following general formula (2), n is 1 or more, m is 0 or more, and m+n is less than 5.
[Formula 2]

General formula (2)
In general formula (2), R represents a divalent organic group. The method according to claim 1,
The pressure-sensitive adhesive composition further comprising 6 parts by mass to 30 parts by mass of an isocyanate compound with respect to 100 parts by mass of the (meth)acrylic polymer. delete delete The method according to claim 1 or 2,
The (meth)acrylic polymer is an acid value of 5 mg / KOH ~ 50 mg / KOH pressure-sensitive adhesive composition. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition according to claim 1 or 2. 7. The method of claim 6,
It further has an optical film, The adhesive sheet which has the said adhesive layer on at least one side of the said optical film. 8. The method of claim 7,
The adhesive sheet wherein the optical film is a polarizing plate.