KR20170069192A - Adhesive layer, and polarizing plate and laminate having adhesive layer - Google Patents

Abstract

It is an object of the present invention to provide a pressure-sensitive adhesive layer for a polarizing plate that exhibits excellent durability under high-temperature and high-humidity conditions and can reduce light leakage and has excellent adhesion with a polycycloolefin-based film. (B) an isocyanate cross-linking agent is added in an amount of 0.1 to 100 parts by weight based on 100 parts by weight of the copolymer (A), and (A) a copolymer of a monomer mixture containing the following monomers (a1) Sensitive adhesive composition comprising: (a1) 30 to 98.8 mass% of a polyoxyalkylene group or an alkoxyalkyl group-containing monomer; (a2) 0.1 to 10 mass% of a hydroxyl group-containing monomer; (a3) 0.1 to 10 mass% of a carboxyl group-containing monomer; (a4) 1 to 69.8 mass% of a (meth) acrylic acid alkyl ester monomer; (a5) 0 to 30 mass% of a copolymerizable monomer other than the above (a1) to (a4); However, the total of the monomers (a1) to (a5) is 100% by mass.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-sensitive adhesive layer,

The present invention relates to a pressure-sensitive adhesive layer, a polarizing plate with a pressure-sensitive adhesive layer, and a laminate.

In recent years, an image display apparatus has been used not only for indoor use but also as part of a vehicle-mounted monitor or an outdoor measurement apparatus.

An optical film, such as a polarizing film, adhered to an image display apparatus is produced by adsorbing, polarizing and orienting a polarizing component such as a dye having dichroism to a polymer film such as polyvinyl alcohol. A protective film is usually provided on the surface of the polyvinyl alcohol film. As a protective film of a polyvinyl alcohol film, triacetyl cellulose (TAC) film has been widely used. The TAC film is highly hygroscopic, and it is known that deformation of the TAC film occurs under the environment of high humid heat and at room temperature, thereby causing deformation of the entire polarizing plate. Further, since the polarizing plate is brittle, it is known that there is a problem that a crack is generated when the polarizing plate is deformed.

Recently, a polycycloolefin-based (COP) film has been used instead of a TAC film as a protective film of a polyvinyl alcohol film in an image device requiring durability. The COP film is advantageous in that it is less brittle and hygroscopic than the TAC film. The COP film is required to have high durability that suppresses the shrinkage of the entire polarizing plate due to shrinkage of the polyvinyl alcohol film, and similarly, the ability to suppress the " light leakage " of the image display apparatus due to shrinkage of the polyvinyl alcohol film. Further, since the COP film has physical properties different from those of the TAC film, there is a problem that when the conventional pressure sensitive adhesive used for bonding the TAC film and the adherend is used for bonding the COP film and the adherend, the adhesion is poor.

In order to solve the above problem, Patent Document 1 discloses an acrylic pressure sensitive adhesive composition comprising a nuclear hydrogenated terpene phenol resin for the purpose of improving the fixability of a polyolefin or a cyclic polyolefin under a high temperature atmosphere. However, when the pressure-sensitive adhesive layer obtained from the acrylic pressure-sensitive adhesive composition is used for a polarizing plate, the light leakage suppressing performance is not sufficient.

Patent Document 2 discloses a pressure-sensitive adhesive for a low-polarity film comprising a high molecular weight polymer obtained by copolymerizing a monomer component containing an alicyclic monomer or an aromatic ring-containing monomer. However, the pressure-sensitive adhesive has insufficient durability and adhesion to a COP film.

Japanese Patent Application Laid-Open No. 2007-224258 Japanese Patent Application Laid-Open No. 2005-53976

It is an object of the present invention to provide a polarizing plate which exhibits excellent durability under a high temperature condition and a high humidity condition and can reduce light leakage and is excellent in adhesion between a glass substrate and a polarizing plate which is a polycycloolefin film, Sensitive adhesive layer which is excellent in adhesiveness to an optical film such as a pressure-sensitive adhesive layer.

Means for Solving the Problems The present inventors have studied diligently to solve these problems. As a result, it has been found that when a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition comprising a copolymer obtained from a monomer mixture having a surface of a pressure-sensitive adhesive layer and a contact angle of water of 90 ° or less and containing a specific amount of a specific monomer is used, And finally completed the present invention.

That is, according to the present invention, there is provided a pressure-sensitive adhesive layer for bonding the polarizing plate to an image display device, wherein the pressure-sensitive adhesive layer has a contact angle of water of 90 ° or less on the surface of the pressure-

(A) a copolymer of a monomer mixture comprising the following monomers (a1) to (a5)

(B) an isocyanate crosslinking agent in an amount of 0.1 to 5 parts by mass based on 100 parts by mass of the copolymer (A)

A pressure-sensitive adhesive layer, and a pressure-sensitive adhesive layer.

(a1) 30 to 98.8 mass% of a polyoxyalkylene group or an alkoxyalkyl group-containing monomer;

(a2) 0.1 to 10 mass% of a hydroxyl group-containing monomer;

(a3) 0.1 to 10 mass% of a carboxyl group-containing monomer;

(a4) 1 to 69.8 mass% of a (meth) acrylic acid alkyl ester monomer;

(a5) 0 to 30 mass% of a copolymerizable monomer other than the above (a1) to (a4); Incidentally, the sum of the monomers (a1) to (a5) is 100% by mass.

The pressure-sensitive adhesive layer is particularly effective when the polarizing plate has a polycycloolefin-based film as a protective film.

The present invention may also be a polarizing plate with a pressure-sensitive adhesive layer having such a pressure-sensitive adhesive layer on at least one surface of the polarizing plate.

According to the present invention, there is also provided a laminate in which a polarizing plate with a pressure-sensitive adhesive layer is further laminated on a glass substrate.

The glass substrate is preferably a glass substrate used particularly for an image display apparatus.

According to the present invention, it is possible to provide a pressure-sensitive adhesive which exhibits excellent durability under high-temperature conditions and high-humidity conditions and exhibits excellent adhesion between the glass substrate and the protective film as a polarizing plate, which is a polycycloolefin-based film, and adhesion between the polarizing plate and an optical film such as a retardation film Layer. ≪ / RTI > Further, the pressure-sensitive adhesive layer can reduce light leakage of the image display apparatus.

1 is a cross-sectional view schematically showing an example of a laminate according to an embodiment of the present invention.
2 is a cross-sectional view schematically showing an example of a laminated body according to an embodiment of the present invention.

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

1. Adhesive layer

The pressure-sensitive adhesive layer according to the present embodiment is a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing an after-mentioned copolymer (A) and an isocyanate-based crosslinking agent (B) as essential components. Is 90 DEG or less.

1.1. Contact angle

Generally, the contact angle is the angle of the contact portion which is generated when the liquid comes into contact with the solid surface. This contact angle is an important measure of the wetting phenomenon because of the surface tension (surface energy) of the solid and the liquid, and the important physical property which shows the wettability of the solid and the liquid when the interface tension of the solid and the liquid is mechanically equilibrium. (1).

? s =? l? cos? +? sl (1)

θ: contact angle

γs: surface tension of solid (surface energy)

γl: surface tension of liquid (surface energy)

γsl: Interfacial tension between solid and liquid

The inventor of the present invention has found that a pressure-sensitive adhesive layer having excellent adhesion to a polycycloolefin-based film can be obtained by setting the contact angle? Of the pressure-sensitive adhesive layer surface with water to be not more than 90 deg., More preferably not less than 40 deg. When the contact angle with water exceeds 90 °, the pressure-sensitive adhesive layer has poor adhesion with the polycycloolefin-based film. On the other hand, in the case of less than 40 DEG, the hydrophilic property of the pressure-sensitive adhesive layer is too high, so that the durability is sometimes deteriorated. When the contact angle with water is not less than 50 DEG and not more than 90 DEG, the balance between adhesion and durability is particularly excellent.

1.2. Pressure-sensitive adhesive composition

1.2.1. Copolymer (A)

The copolymer (A) (hereinafter sometimes referred to simply as the "component (A)") is a copolymer of monomer mixtures comprising the monomers (a1) to (a4) as essential components.

(1) The monomer (a1)

The monomer (a1) is a polyoxyalkylene group or an alkoxyalkyl group-containing monomer. The monomer (a1) preferably has no crosslinkable group. Examples of the crosslinkable group include a hydroxyl group and a carboxyl group. The monomer (a1) is preferably a (meth) acrylic acid ester.

The monomer (a1) is represented, for example, by the formula (a-1).

CH ₂ = CR ¹ -COOR ² (a-1)

R ¹ is a hydrogen atom or a methyl group, and R ² is a group represented by the formula (g-1).

- (R ³ O) _n R ⁴ (g-1)

R ³ is an alkylene group, R ⁴ is an alkyl group, and n is an integer of 1 or more. The number of carbon atoms of the alkylene group is usually 1 to 10, preferably 1 to 5. The number of carbon atoms in the alkyl group is usually 1 to 10, preferably 1 to 4. n is preferably 1 to 20, more preferably 1 to 4, still more preferably 1 to 2.

Examples of the monomer (a1) include alkoxyalkyl (meth) acrylate and alkoxypolyalkylene glycol mono (meth) acrylate. Examples of the alkoxyalkyl (meth) acrylate include methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxypropyl Methoxybutyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate and 4-ethoxybutyl (meth) acrylate. Examples of the alkoxypolyalkylene glycol mono (meth) acrylate include methoxy diethylene glycol mono (meth) acrylate, methoxy dipropylene glycol mono (meth) acrylate, ethoxy triethylene (Meth) acrylate, methoxytriethylene glycol mono (meth) acrylate, methoxytriethylene glycol mono (meth) acrylate, and the like.

Among these, as the monomer (a1), alkoxyalkyl (meth) acrylate in which R ² in formula (a-1) is an alkoxyalkyl group is preferable from the viewpoint of reactivity.

The monomer (a1) may be used alone or in combination of two or more.

Since the component (A) contains a structural unit derived from the monomer (a1), the pressure-sensitive adhesive layer can obtain the effect of adjusting the birefringence, so that the photoelastic coefficient can be optimized, have. The content of the monomer (a1) in the monomer mixture is from 30 to 98.8% by mass, preferably from 50 to 98.8% by mass, from the viewpoint of imparting suitable fixing property (anchoring property) to the polarizing plate of the adherend to the pressure- , And more preferably 50 to 98.3 mass%. In one embodiment, the content of the monomer (a1) in the monomer mixture may be 50 to 97.7 mass%.

(2) The monomer (a2)

The hydroxyl group-containing monomer as the monomer (a2) may impart a crosslinking point with the isocyanate crosslinking agent (B) to the component (A). In order to ensure the durability of the pressure-sensitive adhesive layer, the content of the monomer (a2) in the monomer mixture is 0.1 to 10 mass%, preferably 0.1 to 5 mass%, more preferably 0.1 to 2 mass%.

The monomer (a2) has a polymerizable double bond together with a hydroxyl group. However, the monomer having a carboxyl group is excluded from the monomer (a2).

Examples of the monomer (a2) include hydroxyalkyl (meth) acrylate and alkylene glycol (meth) acrylate. Specific examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) Hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate. Examples of the alkylene glycol (meth) acrylate include polyethylene glycol (meth) acrylate, propylene glycol (meth) acrylate and polypropylene glycol (meth) acrylate.

The monomer (a2) may be used alone or in combination of two or more.

(3) Monomer (a3)

By copolymerizing the monomer mixture containing the carboxyl group-containing monomer which is the monomer (a3), a component (A) having a carboxyl group is obtained. The carboxyl group of the component (A) forms a hydrogen bond in the pressure-sensitive adhesive composition, thereby giving a cohesive force to the pressure-sensitive adhesive layer, thereby improving the durability of the pressure-sensitive adhesive layer. Further, by using the component (A) having a carboxyl group, the pressure-sensitive adhesive layer can improve the adhesion to an adherend. From the viewpoint of obtaining a pressure-sensitive adhesive layer having high durability, the content of the monomer (a3) in the monomer mixture is 0.1 to 10 mass%, preferably 0.1 to 5 mass%, more preferably 0.1 to 2 mass% By mass to 2% by mass. In one embodiment, the content of the monomer (a3) in the monomer mixture may be 1.2 to 2% by mass.

The carboxyl group-containing monomer which is the monomer (a3) has a polymerizable double bond-containing group in addition to the carboxyl group.

Examples of the monomer (a3) include (meth) acrylic acid, a carboxyl group-containing (meth) acrylate, a monomer having neither a carboxyl group nor a polymerizable double bond but a (meth) acryloyl group. Examples of the carboxyl group-containing (meth) acrylate include? -Carboxyethyl (meth) acrylate and 5-carboxypentyl (meth) acrylate. Examples of the monomer having no (meth) acryloyl group and having a carboxyl group and a polymerizable double bond include carboxyl group-containing monomers such as itaconic acid, maleic acid, fumaric acid, crotonic acid and isocrotonic acid, or anhydrides thereof . Among them, from the viewpoint of copolymerization, the monomer (a3) is preferably a (meth) acrylic acid and a carboxyl group-containing (meth) acrylate.

(4) Monomer (a4)

The (meth) acrylic acid alkyl ester monomer which is the monomer (a4) does not contain any of a polyoxyalkylene group, an alkoxyalkyl group and a crosslinkable group.

The alkyl group of the (meth) acrylic acid alkyl ester monomer which is the monomer (a4) usually has 1 to 24 carbon atoms. Examples of the monomer (a4) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, 2-ethylhexyl Acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl Acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and isostearyl (meth) acrylate.

The monomer (a4) may be used alone or in combination of two or more.

The number of carbon atoms in the alkyl chain of the monomer (a4) is preferably from 1 to 20, and more preferably from 1 to 10, from the viewpoint of adjustment of light leakage of the pressure-sensitive adhesive layer of the present invention. The content of the monomer (a4) in the monomer mixture is preferably 1 to 69.8 mass%, more preferably 1 to 50 mass%, and 1 to 49.3 mass% More preferable.

(5) Monomer (a5)

The monomer mixture may contain a copolymerizable monomer other than the above (a1) to (a4) as the monomer (a5). Examples of the monomer (a5) include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) (Meth) acrylamide, N, N-dimethylamino (meth) acrylamide, N, N-dimethyl (Meth) acrylic monomers containing an amide group or an amino group such as acrylamide, N-isopropyl (meth) acrylamide, t-octyl (meth) acrylamide and diacetone (meth) acrylamide; Other nitrogen-containing monomers such as acrylamide, pentamethylpiperidine (meth) acrylate, and acryloylmorpholine; (Meth) acrylic acid ester monomers having an aromatic ring at the ester moiety such as benzyl (meth) acrylate, 2-naphthyl (meth) acrylate and phenoxyethyl (meth) acrylate; (Meth) acrylic acid ester monomers having an alicyclic group such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate; (Meta) acrylate having ether rings such as glycidyl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate; Monomers having an acryloyl group such as acrylonitrile; Styrene-based monomers such as styrene,? -Methylstyrene, o-methylstyrene and p-methylstyrene; Carboxylic acid vinyl esters such as vinyl acetate; Vinylpyridine, N-vinylpyrrolidone, vinylcaprolactam, and vinyl (meth) acryloyl group-containing macromonomers.

The monomer (a5) may be used alone or in combination of two or more. The content of the monomer (a5) in the monomer mixture is 0 to 30 mass%, preferably 0 to 20 mass%.

(6) The total amount of the monomers (a1) to (a4)

From the viewpoint of achieving excellent durability and high adhesion between the glass substrate and the polycycloolefin-based film and high adhesion between the polycycloolefin-based films in the pressure-sensitive adhesive layer of the present invention, the monomer (a1 ), (a2), (a3) and (a4) may be 70 to 100 mass%, preferably 80 to 100 mass%.

(7) Polymerization method

The method of polymerizing 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. In the production of a pressure-sensitive adhesive composition using a copolymer obtained by polymerization , It is preferable to polymerize by solution polymerization from the viewpoint that the treatment process is relatively simple and can be performed in a short time.

At least one kind of an organic solvent, a monomer and a polymerization initiator may be added to the reaction system sequentially. Examples of the organic solvent include benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetralin, Of aromatic hydrocarbons; aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, i-octane, 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; Ketones such as acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone, cyclohexanone, and methylcyclohexanone; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Glycol ethers such as lycoric monobutyl ether; Alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol and t-butyl alcohol; . These organic solvents may be used alone or in combination of two or more.

Among these organic solvents, it is preferable to use an organic solvent, for example, an ester or a ketone, which is less likely to cause chain transfer during the polymerization reaction in the polymerization of the component (A). Particularly, From the viewpoint of ease of reaction and the like, use of ethyl acetate, methyl ethyl ketone, acetone or the like is preferable.

As the polymerization initiator, it is possible to use organic peroxides, azo compounds and the like which can be used in ordinary solution polymerization. Examples of such organic peroxides include t-butyl hydroperoxide, cumene hydrooxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propyl peroxydicarbonate, Bis (4,4-di-tert-butylperoxycyclohexyl) propane, 2,2-bis (4,4- (4,4-di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4- Bis (4,4-di-t-butylperoxycyclohexyl) butane, 2,2-bis (4,4-di-t-octylperoxy) cyclohexyl) propane, 2,2- Hexyl) butane, and the like, and examples of the azo compound include 2,2'-azobis-i-butyronitrile, 2,2'-azobis-2,4-dimethylvaleronite Re, 2,2'-azobis-4-methoxy-2,4- A ballet is methyl may be mentioned a nitrile or the like.

These polymerization initiators may be used alone or in combination of two or more.

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 compound is particularly preferable. The amount of the polymerization initiator to be used is generally 0.01 to 2 parts by mass, preferably 0.1 to 1.0 part by mass based on 100 parts by mass of the total amount of the monomer mixture.

Further, at the time of producing the component (A) contained in the pressure-sensitive adhesive composition, it is possible to use a chain transfer agent as needed within a range not to impair the objects and effects of the present invention.

Such chain transfer agents include, for example, cyanoacetic acid; Alkyl esters of 1 to 8 carbon atoms of cyanoacetic acid; Bromoacetic acid; Alkyl esters of 1 to 8 carbon atoms of bromoacetic acid; Aromatic compounds such as anthracene, phenanthrene, fluorene, and 9-phenylfluorene; aromatic nitro compounds such as p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol and p-nitrotoluene; Benzoquinone derivatives such as benzoquinone and 2,3,5,6-tetramethyl-p-benzoquinone; Borane derivatives such as tributylborane; Tetrabromoethane, tribromethylene, trichlorethylene, bromotrichloromethane, tribromomethane, 3-chloro-1-propene, etc. Halogenated hydrocarbons; Aldehydes such as chloral, furaldehyde and the like; alkylmercaptan captain having 1 to 18 carbon atoms; Aromatic mercaptans such as thiophenol and toluene mercaptan; Mercaptoacetic acid, alkyl esters of 1 to 10 carbon atoms of mercaptoacetic acid; A hydroxyalkylmercapto captain having 1 to 12 carbon atoms; Terpenes such as pinene and terpinolene.

The polymerization temperature in the production of the component (A) is generally about 30 to 180 占 폚, preferably 40 to 150 占 폚, and more preferably 50 to 90 占 폚. The reaction time is generally 4 to 20 hours. When an unreacted monomer is contained in the polymer obtained by the solution polymerization method or the like, it is also possible to purify it by the reprecipitation method using methanol or the like in order to exclude this monomer.

(8) Properties of component (A)

(8-1) Weight average molecular weight and dispersion index

From the viewpoint of enhancing the adhesion between the glass substrate and the polycycloolefin-based film and the adhesion between the polycycloolefin-based films, preventing the light leakage and increasing the durability, the weight average molecular weight (Mw) of the component (A) More preferably 400,000 to 200,000, and more preferably 750,000 to 1,500,000. If the Mw of the component (A) is less than 400,000, the durability may be poor. On the other hand, if the Mw exceeds 200,000, light leakage may not be sufficiently reduced.

The dispersion index (PDI, Mw / Mn) of the component (A) is preferably 10 to 20, more preferably 11 to 15 from the viewpoint of obtaining a pressure-sensitive adhesive layer having excellent adhesion to the polycycloolefin-based film. When the PDI of the component (A) is in the above range, the amount of the low-molecular weight component in the component (A) is small and a pressure-sensitive adhesive layer having excellent durability can be obtained.

Here, Mw and Mn of the component (A) were determined by GPC (gel permeation chromatography) in terms of standard polystyrene in the conditions described in the examples.

(8-2) Glass transition temperature (Tg)

The glass transition temperature (Tg) of the component (A) is preferably from -70 to 0 占 폚, from the viewpoint of preventing light leakage and enhancing the durability and the adhesion between the adherend and the polycycloolefin- More preferably 50 to -10 占 폚. Further, in the present invention, the Tg of the component (A) is a value calculated by the following formula (2) (formula of FOX).

1 / Tg = W _{A a1} / Tg + W _{a1 a2} / Tg + W _{a2 a3} / _a4 Tg _a3 + W / Tg + W _{a4 a5} / Tg _a5 ···· (2)

(In the formula, Tg _A is (A) denotes a glass transition temperature (K) of the component, Tg _a1, Tg _a2, Tg _a3, Tg _a4, Tg _a5 is a monomer (a1), (a2), (a3, respectively), (a4),, monomers contained in the glass transition temperature of the homopolymer (Tg (K)) _{represents, W a1, W a2, W} a3, W a4, W a5 are ingredient (a), each prepared from (a5) (a1), (a2), (a3), (a4) and (a5).

When the monomer (aX) contains two or more kinds of monomers (for example, (aX-1) and (aX-2)) (X is an integer of 1 to 5) The term relating to the monomer (aX) in the formula (2) can be represented by the following formula (3).

W _aX / Tg _aX = W _{aX -1} / Tg _{aX -1} + W _{aX -2} / Tg _{aX -2} (3)

(In the formula, Tg _{aX -1,} Tg _{aX -2} denotes the respective monomers (aX-1), (the glass transition temperature (Tg of the homopolymer prepared from aX-2) (K)) , W aX -1, _{aX -2} W represents the weight fraction in the total structural units of the structural unit derived from the amount of the monomer (aX-1), (aX -2) contained in the respective component (a).)

Further, according to the above equation (2), since Tg _A is calculated as the absolute temperature K, it is converted to the Celsius temperature (占 폚) as needed. The Tg of a homopolymer prepared from a typical monomer is described in, for example, Polymer Handbook Forth Edition (Wiley-Interscience, 2003).

1.2.2. The isocyanate-based crosslinking agent (B)

The isocyanate crosslinking agent (B) (hereinafter sometimes simply referred to as "component (B)") is not particularly limited as long as it is a crosslinking agent capable of crosslinking with the component (A) at room temperature or under heating, For example, there may be mentioned xylene diisocyanate, tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate , Diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate, or an alicyclic or higher alcohol compound such as trimethylolpropane, or the like, Isocyanate compounds, isocyanurate compounds and the like.

Also included are urethane prepolymer type isocyanates obtained by addition reaction of known polyether polyols, polyester polyols, acrylic polyols, polybutadienepolyols, polyisoprene polyols and the like with isocyanate compounds. Of these, tolylene diisocyanate and derivatives thereof are preferably used as the component (B).

The content of the component (B) in the pressure-sensitive adhesive composition is 0.1 to 5 parts by mass based on 100 parts by mass of the component (A), and 0.2 To 1 part by mass.

1.2.3. Other components

The pressure-sensitive adhesive composition 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, (Hereinafter sometimes simply referred to as "component (E)"), (D) an ionic compound (hereinafter sometimes simply referred to as "component (D) An ultraviolet absorber, a tackifier, a plasticizer, and the like may be blended.

(C) Silane coupling agent

When the pressure-sensitive adhesive composition according to the present embodiment contains the component (C), when the pressure-sensitive adhesive layer is formed on the surface of the adherend using the pressure-sensitive adhesive composition according to the present embodiment, the adhesion between the adherend and the pressure- have. Component (C) includes, for example, a polymerizable unsaturated group-containing silicon compound such as vinyltrimethoxysilane, vinyltriethoxysilane and methacryloxypropyltrimethoxysilane; Having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, Silicon compounds; Amino groups such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane Containing silicon compounds; 3-chloropropyltrimethoxysilane; And oligomer-type silane coupling agents. Among them, a silane coupling agent having a functional group reactive with a functional group contained in the component (A) is preferable because it is unlikely to cause peeling in a highly humid environment.

The content of the component (C) in the pressure-sensitive adhesive composition may be from 0.1 to 5 parts by mass, and preferably from 0.2 to 1 part by mass, relative to 100 parts by mass of the component (A) from the viewpoint of satisfactory adhesion with the adherend .

(D) an ionic compound

The pressure-sensitive adhesive composition according to the present embodiment may also contain an ionic compound (D).

As the component (D), for example, an ionic compound having an anion and a cation at 25 ° C in a liquid form or a solid form can be exemplified. Specifically, an alkali metal salt, an ionic liquid ), A surfactant, and the like. When the pressure-sensitive adhesive composition according to the present embodiment contains the component (D), the oxygen atom of the polyoxyalkylene group or the alkoxyalkyl group derived from the component (a1) constituting the component (A) is coordinated to the cation constituting the component High antistatic performance can be realized.

Examples of the alkali metal salts include alkali metal cations such as lithium, sodium and potassium, and compounds comprising anions. Specific examples thereof include sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, potassium chlorate, nitrate potassium acetate, sodium carbonate, sodium, Thiocyanic acid sodium, LiBr, LiI, LiBF _4, LiPF _6, LiSCN, acetic acid, sodium alginate, sodium, lignin sulfonate, sodium toluene sulfonate, sodium, LiCF ₃ SO _3, Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C and the like.

Examples of the cation constituting the ionic liquid include pyridinium cations, piperidinium cations, pyrrolidinium cations, cations having a pyrrolene skeleton, cations having a pyrrole skeleton, imidazolium cations, tetrahydropyridinium cations, pyridinium cation, a pyrazolium cation, pyrazolyl Jolly cation, tetraalkylammonium cations, and the like trialkyl sulfonium cation, a tetraalkylphosphonium cation, as the anion constituting the ionic liquid 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 ^-, and the like ^{_{-, 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 .

Examples of the ionic liquid include ionic compounds which are composed of these cations and anions and are liquid at 25 占 폚. Specific examples of such ionic liquids include 2-methyl-1-pyrrolin tetrafluoroborate, 1-ethyl-2-phenyl indole tetrafluoroborate, 1,2-dimethyl indoletetrafluoroborate, 1- Ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium trifluoromethyltetrahydrofumarate, ethylcarbazole tetrafluoroborate, Ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutainesulfo Ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, (Pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) imide, Butylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, Butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutainesulfo Methylimidazolium bromide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1- (3-methylimidazolyl) 3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl- 3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethyl Imidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoro Borate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoro (Methanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl- N- (2- methoxyethyl) ammonium tetrafluoroborate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, Bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N- (Glycidyl) trimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyl trimethylammonium trifluoromethanesulfonate, glycidyl trimethylammonium bis (pentafluoroethanesulfonyl) imide, Butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridine (1-butyl-3-methylpyridyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, Ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-diethyl-N-methyl- (Trifluoromethanesulfonyl) trifluoroacetamide, glycidyl trimethylammonium (tri (trifluoromethanesulfonyl) trifluoromethanesulfonyl) trifluoromethanesulfonate, diisopropylammonium N-dimethyl-N-ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-pentylammonium bis N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, (Trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, Ponyle) already N, N-dimethyl-N-propyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-heptylammonium bis (trifluormethanesulfonyl) imide, N, N-dimethyl- N-dimethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dihexylammonium N, N-diethyl-N-methyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, Fluoromethanesulfonyl) (Trifluoromethanesulfonyl) imide, triethylpentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, and N, N-diethyl- (Trifluormethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl- N- ethylammonium bis (trifluoromethanesulfonyl) N, N-dimethyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl- N, N-dibutylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium bis (Trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoromethanesulfonyl) Dioxins butyl methyl ammonium bis (trifluoromethanesulfonyl) imide, N- methyl -N- ethyl -N- -N- propyl-pentyl ammonium bis (trifluoromethanesulfonyl) may already be mentioned DE.

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 surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; Polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether; Higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, and sorbitan fatty acid esters; Polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; Polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; Higher fatty acid esters of glycerin such as oleic acid monoglyceride and stearic acid monoglyceride; Polyoxyalkylene such as polyoxyethylene, polyoxypropylene, and polyoxybutylene; And block copolymers thereof.

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

Examples of the anionic surfactant include carboxylates such as sodium laurate, sodium oleate, N-acyl-N-methylglycine sodium salt and polyoxyethylene lauryl ether carboxylate, and salts of sodium dodecylbenzenesulfonate , Sulfonates such as dialkyl sulfosuccinic acid ester salt and dimethyl-5-sulfoisophthalate sodium, sulfuric acid such as sodium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, and polyoxyethylene nonylphenyl ether sulfate Ester salts, phosphoric acid ester salts such as sodium polyoxyethylene lauryl phosphate and sodium polyoxyethylene nonylphenyl ether phosphate.

Examples of the amphoteric surfactant include carboxybetaine type surfactant, aminocarboxylic acid salt, imidazolinium betaine, lecithin, and alkylamine oxides.

In addition, as the component (D), a conductive polymer, conductive carbon, ammonium chloride, aluminum chloride, copper chloride, iron chloride, ammonium sulfate and the like may be used.

Among them, it is preferable to use an alkali metal salt as the component (D).

When the pressure-sensitive adhesive composition according to the present embodiment contains the component (D), the content of the component (D) in the pressure-sensitive adhesive composition may be from 0.1 to 10 parts by mass based on 100 parts by mass of the component (A) The negative case is preferable.

(E) Organic solvent

The pressure-sensitive adhesive composition according to the present embodiment preferably contains the component (E) in order to prepare the coating property. Examples of the component (E) include organic solvents described in the section of "(7) Polymerization Process". The content of the component (E) in the composition may be 50 to 90 parts by mass, preferably 60 to 90 parts by mass, per 100 parts by mass of the component (A).

1.2.4. Preparation of pressure-sensitive adhesive composition

The pressure-sensitive adhesive composition according to the present embodiment is usually prepared by mixing the above components (A) and (B) and optional components, if necessary, either simultaneously or in any order. In the case of mixing the components (A) and (B), when the component (A) is prepared by solution polymerization, the component (B) may be added to the solution containing the component (A) When the component (A) is prepared by bulk polymerization, it is difficult to uniformly mix after completion of the polymerization. Therefore, the component (B) is preferably added and mixed during the polymerization.

1.3. Formation of pressure-sensitive adhesive layer

The pressure-sensitive adhesive layer of the present invention is formed from the pressure-sensitive adhesive composition described above. For example, by carrying out the crosslinking reaction in the pressure-sensitive adhesive composition described above, specifically, the pressure-sensitive adhesive layer can be obtained by crosslinking the component (A) with the component (B). The forming conditions of the pressure-sensitive adhesive layer are, for example, as follows. The pressure-sensitive adhesive composition is coated on a support and dried, usually at 50 to 150 캜, preferably 60 to 100 캜, for 1 to 10 minutes, preferably 2 to 7 minutes, depending on the type of solvent, , To form a coating film. The film thickness of the dried coating film is usually 5 to 75 占 퐉, preferably 10 to 50 占 퐉.

The pressure-sensitive adhesive layer is preferably formed under the following conditions. Sensitive adhesive composition is applied to a support and the release film is stuck on the coating film formed under the above conditions, and then the release film is applied for 3 days or more, preferably 7 to 10 days, usually 5 to 60 캜, preferably 15 to 40 캜, And is generally cured in an environment of 30 to 70% RH, preferably 40 to 70% RH. When the crosslinking is carried out under the above-mentioned aging conditions, it is possible to efficiently form a crosslinked body (network polymer).

The pressure-sensitive adhesive composition may be applied by a known method such as spin coating, knife coating, roll coating, bar coating, blade coating, die coating or gravure coating so as to have a predetermined thickness · Drying method can be used.

As the support and the release film, for example, a polyester film such as polyethylene terephthalate (PET); And plastic films such as polyolefin films such as polyethylene, polypropylene and ethylene-vinyl acetate copolymer.

The gel fraction of the pressure-sensitive adhesive composition according to the embodiment of the present invention is preferably in the range of 0.1 to 10 parts by weight, more preferably 10 to 20 parts by weight, more preferably 10 to 20 parts by weight, It is preferably 50 to 90%, more preferably 60 to 80%.

In the pressure-sensitive adhesive composition according to the present embodiment, the gel fraction may be, for example, the kind and amount of the component (a2) and the component (a3) in the monomer mixture used in preparing the pressure- Can be adjusted according to the type and the amount of usage. The gel fraction was obtained by taking 0.1 g (dry weight (1)) of the cross-linked pressure-sensitive adhesive on a dry weight basis, adding 30 cc of ethyl acetate to the sample bottle, shaking it for 24 hours, And the residue on the wire net is dried at 100 占 폚 for 2 hours to obtain a dry weight (dry weight (2)), which is determined by the following formula (4).

Gel fraction (%) = (dry weight (2) / dry weight (1)) × 100 (4)

2. Polarizer

As the polarizing plate, those used for forming an image display device such as a liquid crystal display device are used. In the present specification, the term " polarizing plate " is used to mean " polarizing film ".

As the polarizing plate, conventionally known polarizing plates can be used. For example, there can be mentioned a polarizing plate and a polarizing plate having a protective film disposed on one side or both sides of the polarizing plate.

As the polarizer, for example, a stretched film obtained by containing a polarizing component in a film made of a polyvinyl alcohol-based resin and stretching can be mentioned. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, polyvinylformal, polyvinyl acetal, and saponified ethylene-vinyl acetate copolymer. The polarizing component includes, for example, iodine or dichroic dye.

Examples of the protective film include films made of cellulose such as acetylcellulose such as triacetylcellulose and diacetylcellulose, polycarbonate film, polyethersulfone film, and polycycloolefin-based film. Among them, when the protective film of the polarizer is a polycycloolefin-based film, shrinkage of the protective film by heating is small, which is preferable.

The thickness of the polarizing plate is usually 30 to 250 탆, preferably 50 to 200 탆.

Further, the polarizing plate may be laminated with layers having different functions such as, for example, an antiglare layer, a retardation layer, and a viewing angle improving layer.

In the present invention, the " polycycloolefin-based film " includes at least 50% of the structural unit derived from the polycycloolefin. The polycycloolefin-based film may be a polycycloolefin copolymer. In this case, the polycycloolefin copolymer is obtained by copolymerizing ethylene and a polycycloolefin (for example, tetracyclododecene) under a Ziegler catalyst .

As the polycycloolefin-based film, a commercially available polycycloolefin-based film can be used. Examples of commercially available polycycloolefin-based films include ZeonoAfilm (made by Nippon Zeon) and Atton's film (made by JSR).

It is also preferable that the surface of the polarizing plate is corona treated. The untreated polycycloolefin-based film has a contact angle of about 100 DEG, but the contact angle is lowered by 40 to 50 DEG by corona treatment. On the other hand, the ordinary pressure sensitive adhesive has a contact angle of about 110 DEG, and even in the case of a polycycloolefin-based film subjected to a corona treatment, adhesion between the pressure-sensitive adhesive and the polycycloolefin-based film is extremely difficult. On the other hand, the pressure-sensitive adhesive layer of the present invention has a contact angle of 90 ° or less and has extremely high adhesion to a polycycloolefin-based film subjected to corona treatment.

3. Pressure-sensitive adhesive sheet with a pressure-sensitive adhesive layer and laminate

The polarizing plate with a pressure-sensitive adhesive layer is a polarizing plate in which the pressure-sensitive adhesive layer is formed on at least one surface of the polarizing plate surface. There is no particular limitation on the method of forming the pressure-sensitive adhesive layer on the surface of the polarizing plate, and a method of applying the pressure-sensitive adhesive composition directly on the surface of the polarizing plate, drying and aging the pressure- . When the pressure-sensitive adhesive layer is transferred onto the surface of the polarizing plate, for example, a double-sided pressure-sensitive adhesive sheet having only a pressure-sensitive adhesive layer, a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed on both surfaces of the substrate, A single-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed on one surface of a substrate, and a pressure-sensitive adhesive sheet to which a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet of the pressure-sensitive adhesive sheet is peeled off. The substrate and the cover film are the same as the materials exemplified in the column of the pressure-sensitive adhesive layer. The forming conditions of the pressure-sensitive adhesive layer and the gel fraction are the same as those described in the column of the pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer is usually 5 to 75 占 퐉, preferably 10 to 50 占 퐉, from the viewpoint of maintaining the adhesive performance. The thickness of the base material and the cover film is not particularly limited, but is usually 10 to 125 占 퐉, preferably 25 to 75 占 퐉.

The polarizing plate with a pressure-sensitive adhesive layer is provided on the surface of the substrate of the liquid crystal cell to produce a liquid crystal device. Here, the liquid crystal cell has a structure in which the liquid crystal layer is sandwiched between two substrates.

A laminate comprising the polarizer, the protective film, the pressure-sensitive adhesive layer of the present invention, and the glass substrate laminated in this order, wherein the polarizer comprises a polarizer and a protective film disposed on the polarizer, Can be manufactured.

1 is a cross-sectional view schematically showing an example of a laminate (laminate 100) according to an embodiment of the present invention. 1, the laminate 100 includes a glass substrate 10, a polycycloolefin-based film 32, and a pressure-sensitive adhesive layer (not shown) provided between the glass substrate 10 and the polycycloolefin- (20). The laminate 100 includes a polarizing film 30 and the polarizing film 30 may include a polycycloolefin-based film 32. [

More specifically, the laminate 100 comprises a glass substrate 10, a pressure-sensitive adhesive layer 20 provided on the glass substrate 10, and a polarizing film 30 ). The polarizing film 30 comprises a polycycloolefin-based film 32, a polyvinyl alcohol film 34 provided on the polycycloolefin-based film 32, and a TAC film 36 provided on the polyvinyl alcohol film 34 . The glass substrate 10 and the polycycloolefin-based film 32 are bonded to each other through the pressure-sensitive adhesive layer 20.

2 is a cross-sectional view schematically showing another example (laminate 200) of the laminate according to one embodiment of the present invention. 2, the laminate 200 includes a glass substrate 10, a polycycloolefin-based film (retardation film) 32, and a polarizing film 130, and the glass substrate 10, A polycycloolefin-based film 32, and a polarizing film 130 are laminated in this order. The polycycloolefin-based film 32 may be a retardation film.

The polycycloolefin-based film 32 and the polarizing film 130 are adhered to each other through the pressure-sensitive adhesive layer 20. The glass substrate 10 and the polycycloolefin-based film 32 are bonded to each other through the pressure-sensitive adhesive layer 22. The polarizing film 130 includes a layer (second polycycloolefin-based film) 38 which is a polycycloolefin-based film or a TAC film, a polyvinyl alcohol film 34 provided on the layer 38, a polyvinyl alcohol film 34). ≪ / RTI > The polycycloolefin-based film (first polycycloolefin-based film) 32 and the layer (second polycycloolefin-based film) 38 are adhered via the pressure-sensitive adhesive layer 20.

The pressure-sensitive adhesive layers 20 and 22 in Figs. 1 and 2 are bonded to an adherend (the pressure-sensitive adhesive layer 20 in Fig. 1 and the pressure-sensitive adhesive layer 22 in Fig. 2) Or the polycycloolefin-based film 32, and in the pressure-sensitive adhesive layer 20 in Fig. 2, the adherend is formed on the surface of the polycycloolefin-based film 32 or the layer 38). As a method of forming the pressure-sensitive adhesive composition on the surface of an adherend, for example, a pressure-sensitive adhesive composition is applied to the surface of a release film (separator) having a good smoothness, the coating film is dried and then the applied film is transferred onto the surface of a specific resin film I can say law enforcement.

The laminate according to the present embodiment is used, for example, in an image display apparatus (particularly, a liquid crystal display apparatus). More specifically, the laminate according to the present embodiment can be used, for example, in an image display device for a touch panel. In this case, the glass substrate included in the laminate according to the present embodiment is preferably a glass substrate for a liquid crystal display device.

The glass substrate constituting the laminate according to the present embodiment may be a glass substrate used for an image display apparatus. The image display device may be, for example, a TFT (thin film transistor) liquid crystal display device used for a liquid crystal television, a computer monitor, a cellular phone, a tablet, and the like.

4. Effects

The pressure-sensitive adhesive layer for bonding the polarizing plate according to the present embodiment to an image display device has an excellent durability while maintaining good adhesion with an adherend by adjusting the contact angle of the pressure-sensitive adhesive layer to a predetermined range. The monomer (a1) in the monomer mixture for forming the component (A) causes the pressure-sensitive adhesive layer to have appropriate transparency and light leakage prevention effect. That is, the present invention relates to a pressure-sensitive adhesive composition comprising a pressure-sensitive adhesive layer (A) formed from a pressure-sensitive adhesive composition containing a component (A), by means of a component (A) formed from a monomer mixture comprising a specific amount of a polyoxyalkylene group or an alkoxyalkyl group- Sensitive adhesive layer having a modulus of elasticity suitable for the polycycloolefin-based film, it is possible to improve the adhesion with the polycycloolefin-based film, and furthermore, the blending of the monomers (a2) to (a4) It is based on a novel and original idea that can combine leak prevention effect and durability.

Example

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

<Heating residue>

About 1 g of precisely weighed tin plate challae polymer solution was weighed, and the total weight was precisely weighed and then heated at 105 DEG C for 3 hours to measure the heating residue (nV). The heating residue was measured in accordance with JIS K 5407: 1997.

<Viscosity Measurement>

The polymer solution was immersed in a constant temperature water bath at 25 캜 for 12 hours, and the viscosity was measured according to the measurement method of the B-type viscometer.

&Lt; GPC measurement condition >

The weight average molecular weight (Mw) and the dispersion index (PDI) of the acrylic polymer were determined by gel permeation chromatography (GPC) under the following conditions.

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

GPC Column Composition: The following five columns (all manufactured by Tosoh Corporation)

(i) TSK-GEL HXL-H (guard column)

(ii) TSK-GEL G7000HXL

(iii) TSK-GEL GMHXL

(iv) TSK-GEL GMHXL

(v) TSK-GEL G2500HXL

Sample concentration: 1.0 mg / cm &lt; ³ &gt;, diluted with tetrahydrofuran

Mobile phase solvent: tetrahydrofuran

Flow rate: 1.0 cm ³ / min

Column temperature: 40 ° C

Standard polystyrene conversion

[Synthesis Example 1] (Synthesis of acrylic polymer 1)

A flask equipped with a stirrer, a nitrogen gas introducing tube, a thermometer and a reflux condenser was charged with 8 parts by mass of butylacrylate, 90 parts by mass of 2-methoxyethyl acrylate, 1 part by mass of acrylic acid and 1 part by mass of 2-hydroxyethyl acrylate And 140 parts by mass of ethyl acetate were charged, and the content of the flask was heated to 70 캜 while nitrogen gas was introduced into the flask. Subsequently, 0.1 part by mass of 2,2'-azobis-i-butyronitrile (AIBN) was added to the flask sufficiently substituted with nitrogen gas under stirring. The contents of the flask were reacted for 8 hours while maintaining the temperature at 70 占 폚. After 8 hours had elapsed, 140 parts by mass of ethyl acetate was added to the reaction mixture to obtain a polymer solution 1 containing the acrylic polymer 1. The heating residue (nV%) at 105 ° C of the obtained polymer solution 1 was 25.2% and the viscosity at 23 ° C was 5.2 Pa · s. The Mw measured by GPC for the obtained acrylic polymer 1 was 90.2 million, and the PDI was 12.

[Synthesis Examples 2 to 8 and 10 to 12] (Synthesis of Acrylic Polymers 2 to 8 and 10 to 12)

A polymer solution containing acrylic polymers 2 to 8 or 10 to 12 was prepared in the same manner as in Synthesis Example 1 except that the polymerizable monomers used in the polymerization reaction were changed as shown in Table 1. The results are shown in Table 1.

[Synthesis Example 9] (Synthesis of acrylic polymer 9)

A flask equipped with a stirrer, a nitrogen gas introducing tube, a thermometer and a reflux condenser was charged with 8 parts by mass of butylacrylate, 90 parts by mass of 2-methoxyethyl acrylate, 1 part by mass of acrylic acid and 1 part by mass of 2-hydroxyethyl acrylate And 120 parts by mass of ethyl acetate were charged, and the content of the flask was heated to 65 캜 while nitrogen gas was introduced into the flask. Subsequently, 0.05 part by mass of AIBN was added to the flask sufficiently substituted with nitrogen gas under stirring. The contents in the flask were reacted for 3 hours while maintaining the temperature at 65 占 폚. Subsequently, 160 parts by mass of ethyl acetate was added dropwise, and the contents in the flask were heated to 75 캜 and reacted for 5 hours. After 8 hours from the start of the reaction, 120 parts by mass of ethyl acetate was added to the reaction mixture to obtain a polymer solution 6 containing the acrylic polymer 6. The heating residue (nV%) of the obtained polymer solution 6 was 20% and the viscosity at 23 캜 was 3.8 Pa · s. The Mw of the obtained acrylic polymer 9 measured by GPC was 1.1 million and the PDI was 24.

The unit of the numerical value of the monomers in Table 1 is the mass part.

The abbreviations in Table 1 have the following meanings.

BA: butyl acrylate (Tg of homopolymer: -50 캜)

2EHA: 2-ethylhexyl acrylate (Tg of homopolymer: -70 ° C)

MEA: 2-methoxyethyl acrylate (Tg of homopolymer: -50 ° C)

AA: Acrylic acid (Tg of homopolymer: 106 DEG C)

HEA: 2-hydroxyethyl acrylate (Tg of homopolymer: -15 캜)

[Example 1]

(1) Preparation of pressure-sensitive adhesive composition

The component (B) and the component (C) were compounded in the mixing ratio shown in Table 2 with respect to 100 parts by mass of the solid content of the polymer solution 1 in the polymer solution 1 containing the acrylic polymer 1 obtained in Synthesis Example 1, did. Here, the solid content refers to the total components excluding the organic solvent from the polymer solution.

(2) Preparation of adhesive sheet

The pressure-sensitive adhesive composition obtained in the above step (1) was applied on a peeled polyethylene terephthalate film (PET film) after bubble draining using a doctor blade at a liquid temperature of 25 DEG C and dried at 90 DEG C for 3 minutes, To form a coating film having a thickness of 25 mu m. The peeled PET film was further adhered to the surface of the coated film opposite to the surface to which the PET film was adhered and allowed to stand for 7 days under an environment of 23 ° C / 50% RH for aging, and a 25 μm thick adhesive Sensitive adhesive sheet was obtained.

(3) Preparation of a polarizing plate with a pressure-sensitive adhesive layer

The pressure-sensitive adhesive composition obtained in (1) was coated on a PET separator using a doctor blade after removing the foam, and dried at 90 占 폚 for 3 minutes to prepare a pressure-sensitive adhesive layer having a thickness of 25 占 퐉. The coated film surface of the sheet was laminated on the COP film surface of a polarizing plate having one surface of a polycycloolefin-based (COP) film and allowed to stand for 1 to 7 days at a room temperature of 23 캜 and a humidity of 65% .

[Examples 2 to 9 and Comparative Examples 1 to 3]

A pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet and a polarizing plate with a pressure-sensitive adhesive layer were obtained in the same manner as in Example 1 except that the blend composition was changed as shown in Table 2 in Example 1.

[evaluation]

(1) Gel fraction

1 g of the pressure-sensitive adhesive layer was taken from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, put into 50 ml of ethyl acetate, and put on a shaker (model shaker SA-300, manufactured by Yamato Kagaku Kogyo Co., Ltd.). The gel content was filtered through a 200 mesh stainless steel mesh and dried. Thereafter, the mass of the sample after filtration divided by the mass of the sample before filtration was calculated as a gel fraction.

(2) Photoelastic coefficient

The PET film was peeled from the pressure-sensitive adhesive sheet for evaluation obtained in the Examples and Comparative Examples, and the pressure-sensitive adhesive layer having a thickness of 25 占 퐉 and the pressure-sensitive adhesive layer laminated together was adjusted to a thickness of 1 mm was placed in an automatic wavelength- Ltd. under the conditions of a measurement wavelength of 600 nm, and the obtained measured value was taken as the photoelastic coefficient.

(3) Contact angle

The polarizer with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 50 mm x 50 mm, and the PET separator was peeled off. Ion exchange water filled in a syringe was dropped onto the surface of the pressure-sensitive adhesive layer at a flow rate of 1 mu L and a flow rate of 0.5 mu L / s, and the contact angle of the pressure-sensitive adhesive layer was measured with a contact angle meter (OCA15EC manufactured by dataphysics).

(4) Durability (heat and humidity test)

The polarizer with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 150 mm x 250 mm to prepare test pieces. The PET separator was peeled off from the test piece and attached to one side of the glass plate using a laminator roll. The test piece was then held in an autoclave adjusted at 5 ° C at 50 ° C for 20 minutes. I wrote two identical trials. One test plate was left for 500 hours under the condition of 80 DEG C for the heat resistance test. The other test plate was allowed to stand for 500 hours under the conditions of 60 占 폚 and 95% RH for humidity resistance test. The peeling of the interface of the glass plate-pressure-sensitive adhesive layer and the occurrence of foaming were visually confirmed based on the following criteria.

(standard)

AA: Appearance defect such as peeling was not observed.

BB: Appearance defects such as peeling were slightly observed.

CC: Appearance defects such as peeling were clearly observed.

(5) Light leakage test

The polarizing plate with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut into a size of 80 mm x 140 mm and attached to both sides of a 1.1 mm-thick non-alkali glass plate using a laminator roll so that the polarization axes thereof were orthogonal to each other. And maintained in an autoclave adjusted to atmospheric pressure for 20 minutes to prepare a trial plate. The test plate was allowed to stand under the condition of a temperature of 80 캜 for 500 hours, and light leakage was observed on the following basis.

(standard)

AA: No light leakage was observed.

BB: Light leakage was slightly observed.

CC: Light leakage was clearly observed.

(6) Adhesion to polarizing plate (COP)

The adhesion of the COP film side of the polarizing plate and the interface of the pressure-sensitive adhesive layer to the test plate after the humidity resistance test was visually confirmed and evaluated according to the following criteria.

(standard)

AA: Appearance defect such as peeling was not observed.

BB: Appearance defects such as peeling were slightly observed.

CC: Appearance defects such as peeling were partially observed.

DD: Appearance defects such as peeling were remarkably observed.

The numerical value of the pressure-sensitive adhesive composition in Table 2 is in parts by mass.

The abbreviations in Table 2 have the following meanings.

L-45: TDI-based curing agent (manufactured by Soken Chemical & Engineering Co., Ltd.)

KBM403: Silane coupling agent (manufactured by Shin-Etsu Silicone Co., Ltd.)

From the results shown in Table 2, it can be seen that the pressure-sensitive adhesive sheet of Examples 1 to 9 is formed from the pressure-sensitive adhesive composition comprising the component (A) and the component (B), and the contact angle of the surface of the pressure- , And the component (A) is a copolymer of the monomer mixture containing the monomers (a1) to (a5) satisfying the predetermined conditions. Therefore, the adhesion between the glass substrate and the polycycloolefin- It can be understood that the adhesion between polycycloolefin-based films is excellent, high durability is achieved, and light leakage can be reduced.

On the other hand, in the pressure-sensitive adhesive sheet of Comparative Example 1, since the pressure-sensitive adhesive layer contained less than 30 mass% of the monomer (a1) in the monomer constituting the component (A), the photoelastic coefficient was not suitable, did. Further, since the contact angle exceeded 90 占 폚, good adhesion to COP was not obtained. Further, it can be understood that the pressure-sensitive adhesive sheet of Comparative Example 2 did not contain the monomer (a2) in the monomer mixture constituting the component (A), so that the durability was inferior and the light leakage test could not be evaluated. Further, it can be understood that the pressure-sensitive adhesive sheet of Comparative Example 3 is inferior in durability because the blending amount of the monomers (a2) and (a3) in the monomer mixture constituting the component (A) is excessive.

10 glass substrate
20, 22 pressure-sensitive adhesive layer
30, 130 polarizing film
32 retardation film (polycycloolefin film)
34 Polyvinyl alcohol (PVA) film
36 TAC film
38 Polycycloolefin-based film or TAC film
100, 200 laminate

Claims (5)

A pressure-sensitive adhesive layer for bonding the polarizing plate to an image display device, wherein the pressure-sensitive adhesive layer has a contact angle of water of 90 DEG or less on the surface of the pressure-
(A) a copolymer of a monomer mixture comprising the following monomers (a1) to (a5)
(B) an isocyanate crosslinking agent in an amount of 0.1 to 5 parts by mass based on 100 parts by mass of the copolymer (A)
Sensitive adhesive composition comprising: a pressure-sensitive adhesive composition comprising:
(a1) 30 to 98.8 mass% of a polyoxyalkylene group or an alkoxyalkyl group-containing monomer;
(a2) 0.1 to 10 mass% of a hydroxyl group-containing monomer;
(a3) 0.1 to 10 mass% of a carboxyl group-containing monomer;
(a4) 1 to 69.8 mass% of a (meth) acrylic acid alkyl ester monomer;
(a5) 0 to 30 mass% of a copolymerizable monomer other than the above (a1) to (a4);
Incidentally, the sum of the monomers (a1) to (a5) is 100% by mass. The method according to claim 1,
A pressure-sensitive adhesive layer characterized in that the polarizing plate has a polycycloolefin-based film as a protective film. A polarizing plate with a pressure-sensitive adhesive layer having the pressure-sensitive adhesive layer according to claim 1 or 2, on at least one surface of the polarizing plate. A laminate obtained by laminating the polarizing plate with a pressure-sensitive adhesive layer according to claim 3 onto a glass substrate. 5. The method of claim 4,
Wherein the glass substrate is a glass substrate used in an image display apparatus.

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