KR20150140711A - Adhesive agent composition for optical films, and adhesive optical film - Google Patents

Abstract

The pressure-sensitive adhesive composition for an optical film comprises (A) a polymer of a monomer mixture comprising (a1) a (meth) acrylic acid ester monomer having a specific structure and (a2) a monomer having one olefinic double bond and at least one hydroxyl group in the molecule An acrylic polymer, and (B) a crosslinking agent having a specific structure.

Description

TECHNICAL FIELD [0001] The present invention relates to a pressure-sensitive adhesive composition for an optical film and a pressure-

The present invention relates to a pressure-sensitive adhesive composition for an optical film and a pressure-sensitive optical film.

BACKGROUND ART [0002] Image display devices have been used in recent years under various uses and conditions. For example, they are used not only at room temperature but also under severe conditions such as high temperature and high temperature and humidity. Examples of the use at a high temperature or a high temperature and a high humidity condition include use in a tropical region, use inside a vehicle or in an outdoor measurement device.

An optical film such as a polarizing film constituting an image display device is produced by adsorbing a dye having dichroism to a polymer film such as polyvinyl alcohol, and stretching and orienting the dye. For this reason, the optical film shrinks under high temperature or high humidity environment, and dimensional distortion is likely to occur. In the case where dimensional deformation occurs in the optical film once, even if the temperature condition or the humidity condition is changed, it is difficult to completely return to the original dimension. As a result, cracks, peeling, and lifting occur in the pressure-sensitive adhesive layer due to the influence of the stress caused by the dimensional change of the optical film, or light leakage due to distortion of the polarization axis occurs in the image display device.

In addition, in recent years, the image display device has been required to have a large screen, high image quality, and high durability. Along with this, various studies have been made on the pressure-sensitive adhesive composition in order to solve defects in appearance such as light leakage caused by dimensional changes of optical films such as polarizing films, peeling and foaming under high temperature and high humidity environments.

Japanese Patent Application Laid-Open No. 2007-169329

The present invention relates to a pressure-sensitive adhesive composition for an optical film capable of exhibiting excellent durability under high-temperature and high-humidity conditions and capable of reducing light leakage when used for adhering an adherend such as a liquid crystal cell and an optical film such as a polarizing film, And an adhesive optical film using the same.

In order to solve such a problem, the present inventors have found that when a pressure-sensitive adhesive composition comprising a crosslinking agent having a predetermined structure is used to form a pressure-sensitive adhesive layer and used for adhering an adherend such as a liquid crystal cell and an optical film such as a polarizing film , And that light leakage can be reduced.

1. A pressure-sensitive adhesive composition for an optical film according to one aspect of the present invention,

(Meth) acrylate ester monomer represented by the following general formula (1) and (a2) an acrylic polymer which is a polymer of a monomer mixture comprising a monomer having one olefinic double bond and at least one hydroxyl group in the molecule Wow,

(B) a crosslinking agent represented by the following general formula (2) or the following general formula (3).

[Chemical Formula 1]

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group or an aralkyl group having 1 to 14 carbon atoms.)

(2)

(In the formula, R ^1A, R ^1B, R ^1C are independently, to a group containing a group represented by formula (4) group and / or the following general formula (5) represented by, R ^2A, R ^2B, R ^2C Is independently a group containing an alkylene group having 2 to 10 carbon atoms.)

(3)

(In the formula, R ^1A, R ^1B, R ^1C are independently, to a group containing a group represented by formula (4) group and / or the following general formula (5) represented by, R ^2A, R ^2B, R ^2C are, each independently, a group comprising an alkylene group of a carbon atom number of 2 or higher than ^{10, R 3A, R 3B, R} 3C, R 3D, R 3E, R 3F , independently of the number of carbon atoms 2 10 or less alkyl And a group containing a phenoxy group.

[Chemical Formula 4]

(Wherein x is an integer of 2 or more and 10 or less, and m is an integer of 1 or more and 10 or less.)

[Chemical Formula 5]

(Wherein X represents a single bond or -O-, y is an integer of 2 or more and 10 or less, and n is an integer of 1 or more and 10 or less.)

2. The pressure-sensitive adhesive composition for an optical film according to 1 above, wherein the amount of the crosslinking agent (B) is 0.05 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the acrylic polymer (A).

3. The pressure-sensitive adhesive composition for an optical film according to 1 or 2 above, wherein the monomer mixture comprises (a1) 90 mass% or more and 99.9 mass% or less of the (meth) acrylic acid ester monomer represented by the general formula (1) And 0.1% by mass or more and 10% by mass or less of a monomer having one olefinic double bond and at least one hydroxyl group in the molecule.

4. The pressure-sensitive adhesive composition for an optical film according to any one of 1 to 3 above, wherein the monomer mixture comprises (a1) the (meth) acrylic acid ester monomer represented by the general formula (1) (Meth) acrylic acid ester monomer represented by the above general formula (1) and having a glass transition temperature (Tg) of 0 DEG C or higher when assuming that the polymer is formed, and (a1-2) homopolymer (Meth) acrylic acid ester monomer represented by the general formula (1), wherein the glass transition temperature (Tg) is less than 0 占 폚, And the total amount of (a1-2) is 90.1% by mass or more and 100% by mass or less).

5. The pressure-sensitive adhesive composition for an optical film according to any one of 1 to 4 above, further comprising 0.01 part by mass or more and 0.5 part by mass or less of the silane coupling agent (C) relative to 100 parts by mass of the acrylic polymer (A) .

6. The pressure-sensitive adhesive composition for an optical film according to any one of 1 to 5 above, further comprising (D) an ionic compound in an amount of 0.01 part by mass or more and 3 parts by mass or less based on 100 parts by mass of the acrylic polymer (A) .

7. The pressure-sensitive adhesive composition for an optical film according to any one of 1 to 6, wherein the microcref value at 60 占 폚 can be 0.50 mm or less.

8. A pressure-sensitive adhesive optical film according to another aspect of the present invention, wherein a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition for an optical film according to any one of 1 to 7 above is formed on one side or both sides of the optical film.

9. The adhesive optical film according to 8 above may be an optical film selected from the group consisting of a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, a brightness improving film and a light diffusion film.

The pressure-sensitive adhesive composition for an optical film according to any one of (1) to (5), which contains the component (B) With the pressure-sensitive adhesive composition having a certain degree of hardness, a suitable cohesive force and elasticity are imparted to the pressure-sensitive adhesive composition. Accordingly, the pressure-sensitive adhesive composition can be provided with both cohesive force and elasticity, which often have a trade-off relationship in many cases. Accordingly, the pressure-sensitive adhesive composition has an appropriate adhesive force and exhibits excellent durability (wet heat durability) under a high temperature condition or a high temperature and a high humidity condition, and when used for adhering an optical film such as a polarizing film to an adherend such as a liquid crystal cell , Light leakage can be reduced. The adhesive optical film using the pressure-sensitive adhesive composition for an optical film is adhered (adhered) to an adherend such as a liquid crystal cell with an appropriate adhesive force, exhibits excellent durability under high temperature conditions or under high temperature and high humidity conditions, When it is used for adhering to an adherend such as a liquid crystal cell, light leakage can be reduced.

1 is a diagram schematically illustrating a method of measuring luminance of an image display apparatus (liquid crystal display panel, VA system) in an embodiment of the present invention.
2 is a diagram schematically illustrating a method of measuring the luminance of an image display apparatus (liquid crystal display panel, TN system) in the embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. In the present invention, unless otherwise specified, "part" means "part by mass" and "%" means "% by mass".

1. Pressure-sensitive adhesive composition for optical film

The pressure-sensitive adhesive composition for an optical film according to one embodiment of the present invention (hereinafter sometimes simply referred to as "pressure-sensitive adhesive composition") is a pressure-sensitive adhesive composition containing an acrylic polymer (A) (hereinafter simply referred to as "component ) And a cross-linking agent (B) represented by the following general formula (2) or the following general formula (3) (hereinafter sometimes simply referred to as "component (B)").

[Chemical Formula 6]

(In the formula, R ^1A, R ^1B, R ^1C are independently, to a group containing a group represented by formula (4) group and / or the following general formula (5) represented by, R ^2A, R ^2B, R ^2C Is independently a group containing an alkylene group having 2 to 10 carbon atoms.)

(7)

(In the formula, R ^1A, R ^1B, R ^1C are independently, to a group containing a group represented by formula (4) group and / or the following general formula (5) represented by, R ^2A, R ^2B, R ^2C are, each independently, a group comprising an alkylene group of a carbon atom number of 2 or higher than ^{10, R 3A, R 3B, R} 3C, R 3D, R 3E, R 3F , independently of the number of carbon atoms 2 10 or less alkyl And a group containing a phenoxy group.

[Chemical Formula 8]

(Wherein x is an integer of 2 or more and 10 or less, and m is an integer of 1 or more and 10 or less.)

[Chemical Formula 9]

(Wherein X represents a single bond or -O-, y is an integer of 2 or more and 10 or less, and n is an integer of 1 or more and 10 or less.)

1.1. (A) Component

The component (A) comprises (a1) a (meth) acrylic acid ester monomer represented by the following general formula (1) and (a2) a monomer mixture comprising a monomer mixture comprising a monomer having one olefinic double bond and at least one hydroxyl group in the molecule Acrylic polymer.

[Chemical formula 10]

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group or an aralkyl group having 1 to 14 carbon atoms.)

In the present invention, the term " acrylic polymer " refers to a polymer containing at least one selected from acrylic acid, an acrylate, an acrylic ester, a methacrylic acid, a methacrylate, and a methacrylate in an amount of 50 mass% . In the present invention, the term "olefinic double bond" refers to a carbon-carbon double bond (C═C). Therefore, the " monomer having one olefinic double bond in the molecule " means a monomer having a carbon-carbon double bond moiety.

Examples of the alkyl group having 1 to 14 carbon atoms represented by R ² in the general formula (1) include linear or branched alkyl groups having 1 to 14 carbon atoms, such as methyl, ethyl, N-butyl, isobutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 2-methylbutyl, 1-methylbutyl, n- N-pentyl group, n-hexyl group, isohexyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, N-decyl group, n-tridecyl group, n-tetradecyl group (myristyl group), and the like. Among them, R ² preferably has an alkyl group of 1 to 10 carbon atoms, more preferably a linear alkyl group of 1 to 10 carbon atoms.

In the present invention, the term " aralkyl group " refers to an alkyl group in which one hydrogen atom of the alkyl group is substituted with an aryl group. Examples of the aralkyl group having 1 to 14 carbon atoms represented by R ² in the general formula (1) include a benzyl group (phenylmethyl group) and a phenethyl group (phenylethyl group).

The content of the component (A) in the pressure-sensitive adhesive composition according to the present embodiment may be 90 parts by mass or more and 99.4 parts by mass or less, and more preferably 95 parts by mass or more and 99.4 parts by mass or less based on 100 parts by mass of the pressure- desirable.

When the pressure-sensitive adhesive composition according to the present embodiment exhibits better adhesion and durability and is used for adhering an optical film such as a polarizing film to an adherend such as a liquid crystal cell or the like, light leakage can be more effectively reduced (Meth) acrylate ester monomer represented by the above general formula (1) (hereinafter sometimes simply referred to as "component (a1)") in an amount of 90 mass% or more (A2) a monomer having one olefinic double bond and at least one hydroxyl group in the molecule (hereinafter simply referred to as " component (a2) " (Preferably 0.6 mass% or more and 7 mass% or less, and more preferably 0.6 mass% or more and 6 mass% or less) of 0.1 mass% or more and 10 mass% or less It is preferably a polymer. In this case, the total amount of the component (a1) and the component (a2) is preferably 90.1% by mass or more and 100% by mass or less.

1.1.1. (a1) Component

The component (a1) can contribute to the adhesive strength and durability of the pressure-sensitive adhesive composition according to the present embodiment. (a1) As the (meth) acrylic acid ester monomer represented by the general formula (1), for example, in the case where the glass transition temperature (Tg) in the case where the homopolymer (a1-1) (Meth) acrylic acid ester monomer represented by the formula (1) (hereinafter sometimes simply referred to as "component (a1-1)") may be used.

Examples of the (meth) acrylic acid ester monomer represented by the above general formula (1), which has a Tg of 0 ° C or more on the assumption that the homopolymer is a component (a1-1), is exemplified by methyl acrylate, methyl methacrylate Propyl methacrylate, n-butyl methacrylate, n-hexadecyl acrylate, n-hexadecyl methacrylate, stearyl acrylate, stearyl acrylate, (Meth) acrylic acid alkyl ester having a linear alkyl group such as methacrylate, and a (meth) acrylic acid alkyl ester having a branched alkyl group such as tert-butyl acrylate, isopropyl methacrylate, isobutyl methacrylate, Methacrylic acid alkyl ester monomers such as cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, dicyclopentanylarc (Meth) acrylic acid ester monomers having an alicyclic group at the ester moiety such as benzyl methacrylate, benzyl acrylate, and 2-naphthyl acrylate, and (meth) acrylic acid ester monomers having a ring- One kind may be used singly or two or more kinds may be used in combination. Among them, the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition according to the present embodiment can further reduce the light leakage of the image display device. The component (a1-1) (Meth) acrylic acid alkyl ester monomer having a Tg of 0 DEG C or higher on the assumption that a polymer is formed, the alkyl chain constituting the (meth) acrylic acid alkyl ester monomer is preferably a linear or branched alkyl chain, It is more preferable to have a branched alkyl chain. In this case, the number of carbon atoms of the alkyl chain is more preferably 1 or more and 10 or less, and more preferably 1 or less, in view of the fact that the pressure-sensitive adhesive layer formed by using the pressure- Or more and 6 or less.

If the content of the component (a1-1) in the monomer mixture for obtaining the polymer as the component (A) is less than 5% by mass, the light leakage may not be sufficiently suppressed. On the other hand, , The pressure-sensitive adhesive layer becomes excessively hard, so that the workability of sticking may be deteriorated or the durability may be adversely affected. The content of the component (a1-1) in the monomer mixture for obtaining the polymer as the component (A) is preferably 5% by mass or more and 55% by mass or less, By mass, and more preferably 5% by mass or more and 40% by mass or less.

(A1) As the (meth) acrylic acid ester monomer represented by the above general formula (1), for example, a glass transition temperature (Tg) in the case of assuming that the homopolymer (a1-2) (Meth) acrylic acid ester monomer represented by the above general formula (1) (hereinafter sometimes simply referred to as "(a1-2) component") may be used.

(meth) acrylate ester represented by the above general formula (1), which has a Tg of less than 0 占 폚 when it is assumed that a homopolymer is used as the component (a1-2), includes, for example, ethyl acrylate, n- Acrylate, n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-hexyl methacrylate, n-pentyl acrylate, n-octyl acrylate, n-octyl methacrylate, (Meth) acrylic acid alkyl ester monomers having a linear alkyl group such as acrylate, lauryl methacrylate, lauryl acrylate, and n-tetradecyl methacrylate, isopropyl acrylate, isobutyl acrylate, isooctyl acrylate (Meth) acrylic acid alkyl ester monomers having a branched alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, isooctyl methacrylate, 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate; (Meth) acrylic acid alkyl ester monomers having a cyclic group of 1 to 30 carbon atoms. One of these monomers may be used alone or two or more of them may be used in combination. Among them, the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition according to the present embodiment can further reduce light leakage. The component (a1-2) has a Tg of less than 0 占 폚 (Meth) acrylic acid alkyl ester monomer represented by the general formula (1), the alkyl chain constituting the alkyl (meth) acrylate is preferably a linear or branched alkyl chain, and the linear alkyl It is more preferable to have a chain. In this case, the number of carbon atoms in the alkyl chain is more preferably 1 or more and 10 or less, because the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition according to the present embodiment can further reduce light leakage of the image display device.

If the content of the component (a1-2) in the monomer mixture for obtaining the polymer as the component (A) is less than 44.5 mass%, the balance of the adhesive property may be broken and the adhesion to the adherend may be insufficient. If it exceeds 94.5 mass%, light leakage may not be sufficiently suppressed. The content of the component (a1-2) in the monomer mixture for obtaining the polymer as the component (A) is preferably 44.5 mass% or more and 94.5 mass% or less, By mass, more preferably from 59.5% by mass to 90% by mass, and still more preferably from 69.5% by mass to 90% by mass.

The total amount of the component (a1-1) and the component (a1-2) in the component (a1) is preferably 49.5 mass% or more and 100 mass% or less, and more preferably 64.5 mass% or more and 100 mass% or less.

1.1.2. (a2) Component

The hydroxyl group contained in the component (a2) reacts with the isocyanate group in the component (B) to form a crosslinked structure. As the component (a2), for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl Acrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-chloropropyl acrylate, 2-hydroxy-3-chloropropyl methacrylate, 2- (Meth) acrylic acid ester monomers such as 2-hydroxy-3-phenoxypropyl methacrylate. These monomers may be used singly or in combination of two or more. Among them, a (meth) acrylic acid ester monomer containing a hydroxyl group of 1 to 6 carbon atoms is preferable.

1.1.3. (a3) Component

(A3) a monomer having one olefinic double bond and at least one reactive functional group other than a hydroxyl group in the molecule (hereinafter simply referred to as " component (a3) " May also be included). In the present invention, the "reactive functional group" refers to a functional group capable of reacting with the component (B), and examples of the reactive functional group contained in the component (a3) include carboxyl group, amino group, amide group, and acid anhydride And at least one group selected from the group consisting of

The reactive functional group contained in the component (a3) acts on the isocyanate group in the component (B) and the hydroxyl group in the component (a2), whereby a crosslinked structure can be efficiently formed. Examples of the component (a3) include carboxyethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, Amide, N, N-dimethylaminopropylacrylamide, diacetone acrylamide, acryloylmorpholine, acrylic acid, methacrylic acid, maleic acid and itaconic acid. Of these, one or more Can be used. Among these, the component (a3) is more preferably at least one selected from acrylic acid and alkylamide, and more preferably acrylic acid, from the viewpoint of excellent efficiency in forming a crosslinked structure.

In order to sufficiently suppress the light leakage and to obtain a pressure-sensitive adhesive layer having excellent durability, the content of the component (a3) in the monomer mixture for obtaining the polymer as the component (A) is 0 mass% to 5 mass% And more preferably 0.1 mass% or more and 2 mass% or less.

In the pressure-sensitive adhesive composition according to the present embodiment, from the viewpoint of achieving good adhesiveness, durability and reduction in light leakage more reliably, it is preferable that the content of the component (a1) in the monomer mixture for obtaining the polymer as the component (A) , the component (a2) and the component (a3) may be 90.1 mass% or more and 100 mass% or less, and more preferably 95 mass% or more and 100 mass% or less.

1.1.4. (a4) Component

The monomer mixture for obtaining the polymer as the component (A) is a monomer other than the component (a4) (a1) to (a3), the monomer having one olefinic double bond in the molecule ) Component ") may be further included. Examples of the component (a4) include macromonomers having a radically polymerizable vinyl group at the end of a monomer obtained by polymerizing vinyl acetate, styrene, acrylonitrile, or a vinyl group. The content of the component (a4) in the monomer mixture for obtaining the polymer as the component (A) is preferably 0% by mass or more and 2% by mass or less.

1.1.5. (a1), (a2), (a3) and (a4)

In the pressure-sensitive adhesive composition according to the present embodiment, from the viewpoint of achieving good adhesiveness, durability and reduction in light leakage more reliably, it is preferable that the content of the component (a1) in the monomer mixture for obtaining the polymer as the component (A) , (a2), (a3) and (a4) may be 90.1 mass% or more and 100 mass% or less, more preferably 95 mass% or more and 100 mass% or less, and further preferably 100 mass% or less.

Further, in the pressure-sensitive adhesive composition according to the present embodiment, the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition according to the present embodiment can reduce the light leakage further, and the content of the monomer having an alkylene oxide group is 5 mass% And it is more preferable that it does not contain a monomer having an alkylene oxide group. Examples of the monomer having an alkylene oxide group include a reactive emulsifier having a (meth) acryl monomer and an alkylene oxide group having an alkylene oxide group in the side chain. In the present invention, "the pressure-sensitive adhesive composition does not contain a monomer having an alkylene oxide group" means that the content of a monomer having an alkylene oxide group in the pressure-sensitive adhesive composition is 2% by mass or less. In particular, the content of the monomer having an alkylene oxide group in the pressure-sensitive adhesive composition is preferably 0% by mass or more and 2% by mass or less.

1.1.6. Tg

In the pressure-sensitive adhesive composition according to this embodiment, the Tg of the component (A) is preferably from -70 deg. C to 0 deg. C, more preferably from -60 deg. C to 60 deg. C, from the viewpoint of achieving good adhesiveness, durability, ° C or more and -10 ° C or less. Further, in the present invention, the Tg of the component (A) is a value calculated by the following formula (6) (formula of FOX).

1 / Tg _A = W _a1 / Tg _a1 + W _a2 / Tg _a2 + W _a3 / Tg _a3 + W _a4 / Tg _a4 (6)

(In the formula, Tg _A is, (A) component of the glass transition represents a temperature (K), Tg _a1, Tg _a2, Tg _a3, Tg _a4 is, (a3, respectively, configured monomer (a1), (a2)), , configuration monomer (a1) contained in the represents a glass transition temperature (Tg (K)) of a homopolymer prepared from (a4), W _a1, W _a2, W _a3, W _a4, respectively, (a) component, the ( a2), (a3) and (a4).

Further, according to the above equation (6), since Tg _A is calculated as the absolute temperature K, it is converted to Celsius temperature (占 폚) as necessary.

The glass transition temperature of a homopolymer prepared from a typical monomer is shown in Table 1 below. More specifically, for example, it is described in Polymer Handbook Third Edition (Polymer Handbook Third Edition, Wiley-Interscience, 1999) have.

1.1.7. Weight average molecular weight (Mw)

In the pressure-sensitive adhesive composition according to the present embodiment, the component (A) preferably has a weight average molecular weight (Mw) of 500,000 or more and 200,000 or more, more preferably 500,000 or more, from the viewpoints of achieving good adhesiveness, durability, And more preferably 800,000 or more and 1.8 million or less. Here, the weight average molecular weight (Mw) of the component (A) is determined by GPC (gel permeation chromatography) under the following conditions in terms of standard polystyrene standards.

≪ GPC measurement condition >

Measuring apparatus: HLC-8120GPC (manufactured by Tosoh Corporation)

GPC Column Composition: The following five columns (all manufactured by Toso Co., Ltd.)

(1) TSK-GEL HXL-H (Guard column)

(2) TSK-GEL G7000HXL

(3) TSK-GEL GMHXL

(4) TSK-GEL GMHXL

(5) TSK-GEL G2500HXL

Sample concentration: 1.0 mg / cm3, diluted with tetrahydrofuran

Mobile phase solvent: tetrahydrofuran

Flow rate: 1.0 cm3 / min

Column temperature: 40 DEG C

It is preferable that the component (A) according to the present embodiment has a molecular weight distribution (weight average molecular weight / number average molecular weight) determined by GPC in the range of 4 or more and 7 or less. In the component (A), the molecular weight distribution of not more than 7 means that the ratio of the high molecular weight component is high and the ratio of the low molecular weight component is small, and therefore, under the durability test conditions, Since the cohesive force of the pressure-sensitive adhesive layer can be maintained, the durability of the pressure-sensitive adhesive layer can be further improved. Further, in the component (A), since the molecular weight distribution is 4 or more, the component (A) becomes a polymer having a molecular weight distribution to some extent, so that the pressure-sensitive adhesive composition containing the component (A) Can be given.

1.2. Component (B)

As described above, in the pressure-sensitive adhesive composition according to the present embodiment, the crosslinking agent as the component (B) includes the crosslinking agent represented by the above-mentioned formula (2) or the above-mentioned formula (3).

The pressure-sensitive adhesive composition according to the present embodiment is preferably a pressure-sensitive adhesive composition which is excellent in adhesion and durability, In the group represented by the general formula (4) wherein R ^1A , R ^1B and R ^1C , x is more preferably an integer of 2 or more and 10 or less (More preferably an integer of 1 or more and 6 or less). Further, in the group represented by the general formula (5) wherein R ^1A , R ^1B and R ^1C contained in the general formula (2) or the general formula (3), y is more preferably an integer of 2 or more and 10 or less , More preferably an integer of 4 to 8, and n is more preferably an integer of 1 or more and 10 or less, and still more preferably an integer of 1 or less and 6 or less. R ^1A , R ^1B , and R ^1C may be the same or different, or a combination of a plurality of them may be used.

Examples of the alkylene group contained in R ^2A , R ^2B , R ^2C , R ^3A , R ^3B , R ^3C , R ^3D , R ^3E and R ^3F in the general formula (2) For example, linear, branched or cyclic, preferably linear. Examples of the alkylene group include methylene, ethylene, propylene, butylene, hexylene, octylene, dodecylene, cyclohexylene and cyclohexanedimethylene. The number of carbon atoms of the alkylene group is preferably 2 or more and 10 or less, and more preferably 4 or less and 8 or less. Each of R ^2A , R ^2B , R ^2C , R ^3A , R ^3B , R ^3C , R ^3D , R ^3E and R ^3F itself may also be an alkylene group. R ^2A , R ^2B and R ^2C may be the same or different. R ^3A , R ^3B , R ^3C , R ^3D , R ^3E and R ^3F may be the same or different.

The component (B) is an isocyanate-based crosslinking agent. More specifically, the component (B) is a skeleton derived from trimethylolpropane (- (O- CH ₂ -) ₃ -C-CH ₂ CH ₃ ) and an isocyanate (-N═C═O) group.

From the viewpoint of imparting appropriate elasticity to the pressure-sensitive adhesive composition relating to the present embodiment, the component (B) has, for example, a degree of crosslinking (number of isocyanate groups contained in one molecule of component (B)) of 1 to 9 And the degree of crosslinking is preferably 3 or more and 6 or less. The component (B) can be obtained, for example, by condensing trimethylolpropane with an acid halide (or an ester or carboxylic acid) having an isocyanate group.

The molecular weight of the component (B) is preferably 500 or more and 10,000 or less, and more preferably 2,000 or more and 7,000 or less, from the viewpoint that the pressure-sensitive adhesive composition according to the present embodiment can more reliably achieve both cohesive force and elasticity.

When the pressure-sensitive adhesive composition according to the present embodiment contains the component (B), it is preferable that the pressure-sensitive adhesive composition according to the present embodiment contains the component (B) An appropriate cohesive force and elasticity are imparted to the pressure-sensitive adhesive composition. Accordingly, the pressure-sensitive adhesive composition can be provided with both cohesive force and elasticity, which often have a trade-off relationship in many cases. Therefore, when the pressure-sensitive adhesive composition of the present invention is used to form an pressure-sensitive adhesive layer of an image display device, the pressure-sensitive adhesive composition can prevent light leakage and increase the adhesive strength and durability (wet heat durability).

In general, when the pressure-sensitive adhesive composition is excessively hard (when the pressure-sensitive adhesive composition has high cohesive strength and low elasticity), the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition may crack. On the other hand, (The cohesive force of the pressure-sensitive adhesive composition is low and the elasticity is high), bubbles may enter the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition, which is not preferable in appearance. On the other hand, when the pressure-sensitive adhesive composition according to the present embodiment includes the component (B), the pressure-sensitive adhesive composition has appropriate cohesive strength and elasticity, so that cracking of the pressure-sensitive adhesive layer can be prevented and bubbles can be prevented from entering the pressure- .

The content of the component (B) in the pressure-sensitive adhesive composition according to the present embodiment is preferably 0.05 (parts by mass) to 100 parts by mass of the component (A) according to the present embodiment from the viewpoint of preventing light leakage and improving adhesion and durability. Mass part or more and 5 mass parts or less, and more preferably 0.1 mass part or more and 4 mass parts or less.

As the component (B), a commercially available crosslinking agent may be used. For example, as the component (B), D-94 (Sowen Chemical Co., Ltd.), E405-70B (Asahi Chemical Industry Co., Ltd.) and MFA-75B (Asahi Chemical Industry Co., Ltd.) can be used.

According to the pressure-sensitive adhesive composition for an optical film according to the present embodiment, it is possible to obtain a pressure-sensitive adhesive composition for optical films which comprises a crosslinking agent represented by the general formula (2) or the general formula (3) (Commercially available isocyanate-based crosslinking agent NY730A (trade name: Mitsubishi Chemical Corporation), L-45 (trade name, manufactured by Soken Chemical Co., Ltd.), Colonate HL (trade name: Nippon Polyurethane Co., Ltd.), etc.) The light leakage can be reliably reduced and the durability (wet heat durability) is excellent.

1.3. Other Ingredients

The pressure-sensitive adhesive composition for an optical film according to the present embodiment may further contain components other than components (A) and (B), if necessary. For example, the pressure-sensitive adhesive composition according to the present embodiment may contain (C) a silane coupling agent (hereinafter sometimes simply referred to as "component (C)") within the range that does not impair the effect of the present invention, D) an ionic compound (hereinafter sometimes simply referred to as "component (D)"), an antioxidant, an ultraviolet absorber, a tackifier, and a plasticizer.

1.3.1. (C) Silane coupling agent

When the pressure-sensitive adhesive composition for an optical film according to the present embodiment contains the component (C), when a pressure-sensitive adhesive layer is formed on the surface of the adherend using the pressure-sensitive adhesive composition for an optical film according to the present embodiment, It can be kept good. The component (C) includes, for example, a polymerizable unsaturated group-containing silicon compound such as vinyltrimethoxysilane, vinyltriethoxysilane and methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, Silicon compounds having an epoxy structure such as 3-glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2- Aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and 3-chloropropyltrimethoxysilane; oligomeric silane A silane coupling agent having a functional group capable of reacting with a functional group contained in the (meth) acrylic copolymer (A) is preferable because it does not easily cause peeling under a humid environment.

The content of the component (C) in the pressure-sensitive adhesive composition for an optical film according to the present embodiment is preferably 0.01 part by mass to 0.5 part by mass with respect to 100 parts by mass of the component (A) from the viewpoint of satisfactory adhesion with the adherend Or less, more preferably 0.05 parts by mass or more and 0.3 parts by mass or less.

1.3.2. (D) an ionic compound

The pressure-sensitive adhesive composition according to the present embodiment may contain an ionic compound (D). When the pressure-sensitive adhesive composition according to the present embodiment contains the component (D), when the pressure-sensitive adhesive composition according to the present embodiment is used to form a pressure-sensitive adhesive layer on the surface of an adherend, charging of the adherend can be effectively prevented. As the component (D), for example, there can be mentioned a liquid or solid ionic compound at 25 ° C, which comprises anion and cation, and specifically includes an alkali metal salt, an ionic liquid (liquid phase ), A surfactant, and the like.

Examples of the alkali metal salt include alkaline metal cation such as lithium, sodium, potassium, and an anion, and specific examples thereof include sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, potassium chlorate, potassium nitrate, nitrate sodium carbonate, sodium thiocyanate, sodium, LiBr, LiI, LiBF _4, LiPF _6, LiSCN, sodium acetate, sodium alginate, lignin sulfonate, toluene _{sulfonate, LiCF 3 SO 3, Li (} CF 3 SO 2) 2 N, Li (CF ₃ SO ₂ ) IN, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) IN and Li (CF ₃ SO ₂ ) ₃ C.

Examples of the cation that constitutes the ionic liquid include piperidinium cation, pyrrolidinium cation, cation having a pyrrolene skeleton, cation having a pyrrole skeleton, imidazolium cation, tetrahydropyrimidinium Examples of the cationic cationic surfactant include cationic cationic surfactants such as cationic surfactants, cationic surfactants, cationic surfactants, cationic surfactants, cationic surfactants, cationic surfactants, cationic surfactants, cationic surfactants, The anions constituting the liquid include Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , ClO ₄ ^- , NO ₃ ^- , CH ₃ COO ^- , CF _{^{3 COO -, CH 3 SO 3}} -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (CF 3 SO 2) 3 C -, AsF 6 -, SbF 6 -, NbF 6 -, TaF 6 ^{-, F (HF) n -} (n = 2 ~ 3), (CN) 2 n -, C 4 F 9 SO 3 -, (C 2 F 5 SO 2) 2 n -, C 3 F 7 COO -, (CF ₃ SO ₂ ) (CF ₃ CO) N ^- and the like.

Examples of the ionic compound include an ionic compound which is composed of these cation and anion and is in a liquid phase at 25 占 폚. Specific examples of such ionic compounds include 2-methyl-1-pyrrolin tetrafluoroborate, 1-ethyl-2-phenyl indole tetrafluoroborate, 1,2-dimethyl indole tetrafluoroborate, 1 Ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate Ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate , 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl- Imidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluoro Butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis Methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1 3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl- 3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethanol 3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoroborate, tetrahexylammonium bis (trifluoromethanesulfonyl) ) Imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethane N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, N, Ethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N- (2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoro (Pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, 1-butylpyridinium ) Trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) (2-methoxyethyl) ammonium (trifluoromethanesulfonyl) trifluoroacetamide, diallyldimethylammonium (trifluoromethanesulfonyl) amide, N, ) Trifluoroacetamide, glycidyltrimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-dimethyl-N-ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-heptylammonium bis N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, Trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imide N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, (Trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylammonium bis (trifluoromethanesulfonyl) imide, Triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoromethanesulfonyl) imide, Methanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, N, N-dipropyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide (Trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium bis (trifluoromethylsulfonyl) imide, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide.

As the surfactant, any of a nonionic surfactant, a cationic surfactant, an anionic surfactant and an amphoteric surfactant can be used.

Examples of the nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether, Sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monolaurate, sorbitan monolaurate, sorbitan monostearate and sorbitan trioleate; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; Polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride; polyoxyethylene higher fatty acid esters such as polyoxyethylene, poly Polyoxyalkylenes such as oxypropylene, polyoxybutylene, and the like Renryu and there may be mentioned a block copolymer of them.

Examples of the cationic surfactant include alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, benzalkonium chloride salt, and alkyldimethylammonium ethosulfate.

Examples of the anionic surfactant include carboxylates such as sodium laurate, sodium oleate, N-acyl-N-methylglycine sodium salt and sodium polyoxyethylene lauryl ether carboxylate, sodium dodecylbenzenesulfonate, di Sulfonic acid salts such as alkylsulfosuccinic acid ester salts and sodium dimethyl-5-sulfoisophthalate, sulfuric acid ester salts such as sodium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate and sodium polyoxyethylene nonylphenyl ether sulfate, polyoxyethylene lauryl Phosphoric acid ester salts such as sodium phosphate, polyoxyethylene nonylphenyl ether phosphate and the like.

Examples of the amphoteric surfactant include carboxybetaine type surfactants, aminocarboxylic acid salts, imidazolinium betaines, lecithin and alkylamine oxides. In addition, a conductive polymer, conductive carbon, ammonium chloride, aluminum chloride, copper chloride, iron chloride, ammonium sulfate, and the like may be used.

Among them, an organic salt of a liquid is preferably used at 25 占 폚.

The content of the component (D) in the pressure-sensitive adhesive composition for an optical film according to the present embodiment may be 0.01 part by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the component (A) And preferably 2.5 parts by mass or less.

1.4. Method of polymerization of component (A)

The polymerization method of the component (A) is not particularly limited, and it can be polymerized by a known method such as solution polymerization, emulsion polymerization, suspension polymerization, etc. However, by using a mixture of the copolymer obtained by polymerization, In preparing a pressure-sensitive adhesive composition, it is preferable to polymerize by solution polymerization from the viewpoint that the treatment process is relatively simple and can be carried out in a short time.

The solution polymerization is generally carried out by feeding a predetermined organic solvent, each monomer, a polymerization initiator, a chain transfer agent and the like, which are used as necessary, into a polymerization vessel, and heating and stirring for several hours under a nitrogen stream or at the reflux temperature of the organic solvent .

In this case, at least a part of the organic solvent, the monomer and / or the polymerization initiator may be added sequentially. Examples of the organic solvent include organic solvents such as benzene, toluene, ethylbenzene, n-propylbenzene, tert-butylbenzene, o-xylene, m-xylene, p-xylene, tetraline, decalin, Aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, isooctane, n-decane, dipentene, petroleum spirit, petroleum naphtha and turpentine; Esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate and methyl benzoate, For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether Butyl alcohol, isobutyl alcohol, s-butyl alcohol, tert-butyl alcohol, isopropyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, And alcohols such as alcohol; and the like. These organic solvents may be used alone or in combination of two or more.

In the polymerization of the component (A), it is preferable to use an organic solvent (e.g., an ester or a ketone) that does not generate chain transfer during the polymerization reaction, The use of ethyl acetate, methyl ethyl ketone, acetone or the like is preferable from the viewpoints of solubility of the solvent and ease of polymerization.

As the polymerization initiator, it is possible to use organic peroxides, azo compounds and the like that can be used in ordinary solution polymerization. Such organic peroxides include, for example, tert-butyl hydroperoxide, cumene hydrooxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, diisopropyl peroxydicarbonate, di- (4,4-di-tert-butylperoxycyclohexyl) propane, 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) propane, ethylhexyl peroxydicarbonate, Bis (4,4-di-tert-octylperoxycyclohexyl) propane, 2,2-bis Propane, 2,2-bis (4,4-di-tert-butylperoxycyclohexyl) butane and 2,2-bis (4,4-di-tert-octylperoxycyclohexyl) Azo compounds such as 2,2'-azobis-isobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis-4- Methoxy-2,4-dimethylvaleronitrile, and the like.

Among these polymerization initiators, a polymerization initiator which does not cause a graft reaction during the polymerization reaction of the component (A) is preferable, and an azo-based polymerization initiator is particularly preferable. The amount thereof is usually 0.01 part by mass or more and 2 parts by mass or less, preferably 0.1 part by mass or more and 1.0 part by mass or less based on 100 parts by mass of the total amount of monomers.

In the production of the component (A) contained in the pressure-sensitive adhesive composition of the present invention, a chain transfer agent is not usually used, but it is possible to use the chain transfer agent as long as it does not impair the objects and effects of the present invention .

Examples of the chain transfer agent include cyanoacetic acid, alkyl esters having 1 to 8 carbon atoms of cyanoacetic acid, bromoacetic acid, alkyl esters having 1 to 8 carbon atoms of bromoacetic acid, anthracene, phenanthrene Aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol and p-nitrotoluene, aromatic compounds such as benzo Benzoquinone derivatives such as quinone and 2,3,5,6-tetramethyl-p-benzoquinone, borane derivatives such as tributylborane, carbon tetrabromide, carbon tetrachloride, 1,1,2,2- Aldehydes such as chloral, furaldehyde and the like: aliphatic hydrocarbons having 1 or more carbon atoms, such as benzene, toluene, toluene, xylene, Alkyl mercaptans of 18 or less; Aromatic hydrocarbons such as benzene, toluene, toluene, and toluene mercaptan; mercaptoacetic acid, mercaptoacetic acid, alkyl esters having 1 to 10 carbon atoms, hydroxyalkylmercaptans having 1 to 12 carbon atoms, Terpenes and the like.

The polymerization temperature of the component (A) is generally about 30 ° C to 180 ° C, preferably 40 ° C to 150 ° C, and more preferably 50 ° C to 90 ° C. When an unreacted monomer is contained in the polymer obtained by a solution polymerization method or the like, it may be purified by a reprecipitation method using methanol or the like in order to remove the monomer.

1.5. Smile creep value

From the viewpoint of further reliably preventing light leakage and further increasing the adhesive force and durability in the pressure-sensitive adhesive composition according to the present embodiment, the microcref value at 60 ° C of the pressure-sensitive adhesive composition according to the present embodiment is , And when the load of 800 g is added for 1000 seconds, it is preferably 0.50 mm or less, more preferably 0.35 mm or less. In the present invention, the micro creep value can be measured using the method described in the embodiment.

The pressure-sensitive adhesive composition according to the present embodiment is preferable from the viewpoint of suppressing shrinkage of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition and consequently suppressing shrinkage of the optical film on which the pressure- It is preferable that the difference between the microcref value at 60 ° C and the microcref value at 23 ° C is small. For example, when the difference between the microcref value at 60 ° C and the microcref value at 23 ° C is 0.30 mm .

1.6. Preparation of pressure-sensitive adhesive composition

The pressure-sensitive adhesive composition according to the present embodiment is usually prepared by mixing the components (A) and (B) and optional components as needed, either simultaneously or in any order. When the component (A) is prepared by solution polymerization in the mixing of the component (A) and the component (B), the component (B) may be added to the solution containing the component (A) When component (A) is prepared by mass polymerization, it is difficult to uniformly mix after completion of polymerization, and therefore it is preferable to add component (B) during the polymerization and mix.

1.7. Uses and effects

The pressure-sensitive adhesive composition according to the present embodiment can be suitably used as an adhesive for an optical film (details of which will be described later). The pressure-sensitive adhesive composition according to the present embodiment exhibits excellent durability under high-temperature and high-humidity conditions and can reduce light leakage when it is used for adhering an optical film such as a polarizing film to an adherend such as a liquid crystal cell . In the case where the image display apparatus includes a retardation film, an adhesive layer using the pressure-sensitive adhesive composition according to the present embodiment can be formed between the retardation film and the polarizing film because a retardation film is formed between the liquid- have.

For example, when the pressure-sensitive adhesive composition according to the present embodiment is used for adhering an adherend such as a liquid crystal cell or the like to an optical film such as a polarizing film, a good light leakage preventing property and high durability can be realized, Can be achieved. In this case, the pressure-sensitive adhesive composition according to this embodiment can be used as an adhesive to which a polarizing film for VA mode, a polarizing film for TN mode, or a polarizing film for IPS mode is adhered, but in view of achieving high image quality, Polarizing film for polarizing film or a polarizing film for TN mode as an adherend.

It is presumed that the light leakage preventing characteristic, which is a mono-action effect of the pressure-sensitive adhesive composition according to the present embodiment, is due to the following mechanism of action.

That is, when a pressure-sensitive adhesive layer is formed on the surface of an optical film (polarizing film) using the pressure-sensitive adhesive composition according to the present embodiment, the pressure-sensitive adhesive composition has component (B) A proper cohesive force and elasticity are imparted to the pressure-sensitive adhesive composition in such a state that the pressure-sensitive adhesive composition has a certain degree of hardness due to the group represented by the general formula (4) and / or the group including the group represented by the general formula (5). Accordingly, the pressure-sensitive adhesive composition can be provided with both cohesive force and elasticity, which often have a trade-off relationship in many cases. Accordingly, when the pressure-sensitive adhesive composition is used to form the pressure-sensitive adhesive layer of an image display apparatus, light leakage can be prevented, and adhesion and durability (wet heat durability) can be increased.

2. Adhesive type optical film

In the adhesive optical film according to another embodiment of the present invention, a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition for an optical film according to the above embodiment is formed on one side or both sides of the optical film. In producing the pressure-sensitive adhesive optical film according to this embodiment, the pressure-sensitive adhesive layer may be formed by applying the pressure-sensitive adhesive composition on an optical film by a gravure coater, a Meyer bar coater, an air knife coater, a roll coater, The applied pressure-sensitive adhesive composition may be formed by drying and crosslinking at room temperature or by heating, or may be formed by forming a pressure-sensitive adhesive layer on a release film and transferring the pressure-sensitive adhesive layer onto the optical film. The thickness of the pressure-sensitive adhesive layer is usually from 1 to 50 μm, preferably from 5 to 30 μm. Before use of the adhesive optical film, a release film may be laminated on the surface of the pressure-sensitive adhesive layer in order to protect the pressure-sensitive adhesive layer.

The adhesive optical film according to the present embodiment may be one used in an image display device such as an FPD or the like. For example, a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, And an optical film selected from the group consisting of a diffusion film. The thickness of the optical film may be appropriately selected depending on the intended use, but is usually from 10 탆 to 500 탆, and preferably from 15 탆 to 300 탆.

3. Example

Hereinafter, the present invention will be described based on the following examples, but the present invention is not limited to the examples.

3.1. Preparation of the component (A)

A monomer mixture having the mixing ratio shown in Table 2 below was charged into a reaction apparatus equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, and then ethyl acetate was added in such an amount that the monomer concentration was 50 mass% . Subsequently, 0.1 part by mass of azobisisobutyronitrile was added, stirring was performed while air in the reaction vessel was replaced with nitrogen gas, the temperature was raised to 60 占 폚, and the reaction was carried out for 8 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to obtain a component (A) (acrylic polymers A to G).

3.2. Manufacture of Polishing Plate for Adhesive Process for Evaluation

3.1. The components (A) obtained in (1) and (2) were added to each of the components shown in Tables 3 and 4 (solid components) to obtain a solution of the pressure-sensitive adhesive composition of Examples 1 to 15 and Comparative Examples 1 to 11. The solution of the pressure-sensitive adhesive composition was coated on the surface of the exfoliated polyester film and dried to obtain a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a thickness of 20 占 퐉. This adhesive sheet was attached to one side of the VA mode polarizing film, and then aged in the dark at 7 deg. C / 50% RH for 7 days to obtain a pressure-sensitive adhesive polarizing plate for evaluation. Crosslinking agents 1 to 6 were used as the component (B), as shown in Tables 3 and 4 below. Each of the crosslinking agents 1 to 6 has a structure represented by the following structural formulas (7) to (12). The weight average molecular weight (MW) of the crosslinking agent 1 is about 3,700, the weight average molecular weight (MW) of the crosslinking agent 2 is about 4,000, and the weight average molecular weight (MW)

[Crosslinking agent 1]

(11)

(Wherein, 1 is 1 or more and 10 or less, m is 1 or more and 10 or less, n is 1 or more and 10 or less, a is 1 or more and 10 or less, b is 1 or more and 10 or less, to be.)

[Crosslinking agent 2]

[Chemical Formula 12]

(Wherein l is 1 or more and 10 or less, m is 1 or more and 10 or less, and n is 1 or more and 10 or less.)

[Crosslinking agent 3]

[Chemical Formula 13]

(Wherein l is 1 or more and 10 or less, m is 1 or more and 10 or less, and n is 1 or more and 10 or less.)

[Crosslinking agent 4]

[Chemical Formula 14]

[Crosslinking agent 5]

[Chemical Formula 15]

[Crosslinking agent 6]

[Chemical Formula 16]

For each evaluation adhesive working polarizing plate, the maximum strain rate, distortion recovery rate, light leakage (LED method using light source: LED method), light leakage (no light source used LED: (Non-LED type), and wet heat resistance (foaming and thermal insulation) were evaluated in the following manner.

3.3. Assessment Methods

3.3.1. Light leakage

A pressure-sensitive adhesive process polarizing plate for evaluation, in which a peeled polyester film was peeled off, was laminated on a 19-inch VA type liquid crystal panel (manufactured by I / O Data Corporation, type: LCD-A191EW) The sample was allowed to contact in the atmosphere at 80 캜 for 240 hours, and then allowed to stand at 23 캜 / 50% RH for 2 hours. Thereafter, the liquid crystal panel in which the polarizing plate was laminated was connected to a personal computer in a dark room, and full-screen black display was performed. In this test, evaluation was performed using two types of liquid crystal panels, that is, a VA liquid crystal panel and a TN liquid crystal panel. 1, the luminance (La, Lb, Lc, Ld) in the area of 1 cm in diameter in the vicinity of each corner and the area of 1 cm in diameter in the central part of the monitor (Lcenter) was measured using a luminance meter (model name: RISA-COLOR / CD8, manufactured by Highland Corporation) and the light leakage property? L was calculated based on the following equation . The smaller ΔL means less light leakage (from the backlight), and if ΔL is less than 2.0, it can be used as a liquid crystal display panel.

? L = (La + Lb + Lc + Ld) / 4 - Lcenter (13)

1, the range R where the light leakage occurred in the vicinity of the corner of the display monitor is visually measured, and with respect to the liquid crystal panel of the TN system, As shown by the dotted line in FIG. 2, the range R where light leakage occurred in the vicinity of the periphery of the display monitor was visually measured. The smaller the range in which light leakage occurs, the smaller the light leakage is. Generally, if R is less than 20 mm, it can be used as a liquid crystal display panel. More preferably less than 16.5.

3.3.2. Smile creep value

Each evaluation adhesive processed polarizing plate for cutting the adhesive processed polarizing plate for each evaluation to the width 10 ㎜ × length 100 ㎜ and bare the peeling treatment the polyester film, the pressure-sensitive adhesive layer is in contact with the glass, and 100 ㎜ ² (10 ㎜ × 10 Mm), and the mixture was autoclaved (50 DEG C, 5 atm), and then allowed to stand under an atmosphere of 23 DEG C / 50% RH for 24 hours. This was used as a specimen for micro creep test. A sample set for test was set at a length of 15 mm of a fixing chuck portion in a chamber box of a micro creep measuring instrument (manufactured by Eiko Kogyo Co., Ltd., model name: TA, TX, PLUS). When the upper and lower sides of the test sample were fixed and a load of 800 g was added in the vertical direction for 1000 seconds, the distance between the specimen and the adherend was deviated from the initial value.

3.3.3. Moist heat durability

An adhesive process polarizing plate for peeling off the peeled polyester film was cut to a size of 15 inches (233 mm 309 mm), and a pressure-sensitive adhesive layer was brought into contact with the glass plate on one side of a 0.5 mm- Using a roll. After the application, the plate was pressurized with an autoclave (manufactured by Kurihara Co., Ltd.) under the conditions of 0.5 MPa and 50 캜 for 20 minutes to obtain a test plate. The test plate thus obtained was allowed to stand under the condition of 60 占 폚 / 90% RH for 500 hours. After completion of the test, the test plate was taken out of the test environment and allowed to stand under an atmosphere of 23 DEG C / 50% RH for 2 hours. Thereafter, the foaming (lack of cohesion) and adiabatic Were evaluated by the following evaluation criteria.

(Foam-size)

○: No foaming at all

?: The diameter of the foaming is not more than 1 mm

X: diameter of foaming is larger than 1 mm

(Foam-generated amount)

○: No foaming at all

: The number of foams was 10 or less

X: Number of foams is more than 10

(Insulation - Size)

○: Insulation is not seen at all

?: Less than 5% of the total area (100%) of the fusion region in the test plate

X: The area where the heat insulation occurred was not less than 5% (100%) with respect to the entire joining portion in the test plate

(Insulation - Position)

○: No insulation

?: Only one-cm-wide region near each end of the test plate has defects

X: There is a defect outside the 1 cm area and the area near each end of the test plate

The abbreviations in Table 2 have the following meanings.

AA: Acrylic acid

BA: n-butyl acrylate

t-BA: tert- (tertiary) butyl acrylate

4-HBA: 4-hydroxybutyl acrylate

HEA: 2-hydroxyethyl acrylate

L-45: TDI isocyanate compound (L-45 manufactured by Soken Chemical & Engineering Co., Ltd.)

MA: methyl acrylate

KBM-403: 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.)

Ionic compound (component (D): antistatic agent): 1-octyl-4-methylpyridinium bis (fluorosulfonyl) imide

The results of Tables 3 and 4 show that the compositions of Examples 1 to 15 contain crosslinking agents 1 to 3 represented by the general formula (2) or the general formula (3) as the component (B) It is possible to realize excellent durability and to reduce light leakage. On the other hand, the compositions of Comparative Examples 1 to 11 did not contain the crosslinking agent represented by the general formula (2) or the general formula (3) as the component (B) 2) or the structure represented by the above-mentioned general formula (3) (Comparative Examples 1 to 11), it was understood that the reduction of light leakage could not be sufficiently achieved.

100: Image display device (liquid crystal panel)
La, Lb, Lc, and Ld: luminance near the corner of the image display device
Lcenter: Luminance at the center of the image display device

Claims (9)

(Meth) acrylate ester monomer represented by the following general formula (1) and (a2) an acrylic polymer which is a polymer of a monomer mixture comprising a monomer having one olefinic double bond and at least one hydroxyl group in the molecule Wow,
(B) a pressure-sensitive adhesive composition for an optical film comprising a cross-linking agent represented by the following general formula (2) or (3)
[Chemical Formula 1]

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group or an aralkyl group having 1 to 14 carbon atoms.)
(2)

(In the formula, R ^1A, R ^1B, R ^1C are independently, to a group containing a group represented by formula (4) group and / or the following general formula (5) represented by, R ^2A, R ^2B, R ^2C Is independently a group containing an alkylene group having 2 to 10 carbon atoms.)
(3)

(In the formula, R ^1A, R ^1B, R ^1C are independently, to a group containing a group represented by formula (4) group and / or the following general formula (5) represented by, R ^2A, R ^2B, R ^2C are, each independently, a group comprising an alkylene group of a carbon atom number of 2 or higher than ^{10, R 3A, R 3B, R} 3C, R 3D, R 3E, R 3F , independently of the number of carbon atoms 2 10 or less alkyl And a group containing a phenoxy group.
[Chemical Formula 4]

(Wherein x is an integer of 2 or more and 10 or less, and m is an integer of 1 or more and 10 or less.)
[Chemical Formula 5]

(Wherein X represents a single bond or -O-, y is an integer of 2 or more and 10 or less, and n is an integer of 1 or more and 10 or less.) The method according to claim 1,
(B) a crosslinking agent in an amount of 0.05 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the acrylic polymer (A). 3. The method according to claim 1 or 2,
Wherein the monomer mixture comprises (a1) 90 mass% or more and 99.9 mass% or less of the (meth) acrylic acid ester monomer represented by the general formula (1) And 0.1% by mass or more and 10% by mass or less of the monomer. The method of claim 3,
(A1) the (meth) acrylic acid ester monomer represented by the general formula (1), wherein the glass transition temperature (Tg) when assuming that the homopolymer (a1-1) (Meth) acrylic acid ester monomer represented by the general formula (1) in an amount of 5 mass% or more and 55 mass% or less and a glass transition temperature (Tg) in a case where it is assumed that a homopolymer (a1-2) Wherein the total amount of (a1-1) and (a1-2) is not less than 90.1% by mass and not more than 100% by mass, the total amount of the (meth) acrylic acid ester monomer represented by the formula (1) Sensitive adhesive composition for an optical film. 5. The method according to any one of claims 1 to 4,
(C) a silane coupling agent in an amount of 0.01 part by mass or more and 0.5 part by mass or less based on 100 parts by mass of the acrylic polymer (A). 6. The method according to any one of claims 1 to 5,
(D) an ionic compound in an amount of 0.01 part by mass or more and 3 parts by mass or less based on 100 parts by mass of the acrylic polymer (A). 7. The method according to any one of claims 1 to 6,
And the microcref value at 60 占 폚 is 0.50 mm or less. A pressure-sensitive adhesive optical film comprising a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 7 on one side or both sides of an optical film. 9. The method of claim 8,
Wherein the optical film is an optical film selected from the group consisting of a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, a brightness enhancement film, and a light diffusion film.

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