KR20190066527A - Adhesive composition for optical film, adhesive layer, optical member and optical display apparatus - Google Patents

Abstract

The present invention relates to an adhesive composition for an optical film, which has good processibility, has improved durability and reworkability under severe conditions, has sufficiently suppressed light leakage, and further has suppressed bending or pressing. The adhesive composition comprises (meth)acrylate copolymers (A), peroxides (B), a crosslinker (C) different from peroxides, and a solvent (D). In particular, a content of the peroxides (B) is more than 2.0 parts by mass or 10 parts by mass or less with respect to 100 parts by mass of the (meth)acrylate copolymers (A); the crosslinker (C) different from peroxides does not contain a block isocyanate compound; the (meth)acrylate copolymers (A) has a weight average molecular weight of 300,000 to 1,200,000 by gel permeation chromatography (GPC); a content of solids including the (meth)acrylate copolymers (A) in the adhesive composition for an optical film is 20 mass% or more with respect to the total mass of the adhesive composition for an optical film; a content of the solvent (D) in the adhesive composition for an optical film is 80 mass% or less with respect to the total mass of the adhesive composition for an optical film; and the viscosity of the adhesive composition for an optical film as measured at 23°C by a B-type viscometer (rotation count 20 rpm) is 200 mPa·s or more and 5,000 Pa·s or less.

Description

TECHNICAL FIELD [0001] The present invention relates to a pressure-sensitive adhesive composition for an optical film, a pressure-sensitive adhesive layer, an optical member, and an image display device.

The present invention relates to a pressure-sensitive adhesive composition for an optical film. The present invention also relates to a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition for a corresponding optical film, an optical member using the pressure-sensitive adhesive layer, and an image display apparatus using the optical member.

In addition to a polarizing film (polarizing plate) which is indispensable to a liquid crystal panel such as a liquid crystal display, which is a kind of image display apparatus, various optical members such as optical films are adhered to improve display quality of the display. When an optical member such as an optical film is adhered to a liquid crystal panel or when two or more optical films of the same kind or different types are adhered, an adhesive is usually used.

As a necessary property of the pressure-sensitive adhesive, durability in an adhesive state of a pressure-sensitive adhesive which does not cause defects such as peeling or peeling due to the pressure-sensitive adhesive is required for durability tests such as heating and humidification, Particularly, in optical films used in automotive panels in recent years, it is demanded that defects such as foaming or peeling due to a pressure-sensitive adhesive do not occur in a durability test under a high temperature and high humidity environment as compared with the prior art.

In addition, when the optical films are adhered to each other and adhered to each other with the use of a pressure-sensitive adhesive, the optical films are peeled off from the liquid crystal panel and adhered to each other It is necessary. Particularly, in recent years, the use of liquid crystal display devices such as thin liquid crystal panels using chemically etched glass in addition to the conventional steps of manufacturing liquid crystal display devices is increasing, and the optical films are also thin and easily broken. If a pressure sensitive adhesive intended only for the conventional durability is used for such a thin liquid crystal display device or a thin optical film, there is a problem that the thin liquid crystal display device or the thin optical film is broken or broken. As a result, there has been a demand for a property of a pressure-sensitive adhesive called "re-workability" in which there is no residue of a pressure-sensitive adhesive on a liquid crystal display device or the like in the peeling process, and the optical film can be easily peeled off. Further, in a thin liquid crystal panel, deflection occurs in the liquid crystal panel due to expansion or contraction of the optical film due to heating and humidification, and the display quality is lowered due to contact with the liquid crystal panel. However, if the stress relaxation property of the pressure-sensitive adhesive is increased in order to alleviate the expansion or contraction of the optical film due to heating and humidification, the processability and dents become worse and the defective rate in the process deteriorates.

In addition, in the case of a pressure-sensitive adhesive optical film used in a general-purpose product such as a television (TV), reduction of the production cost is required, and it is necessary to increase the line speed of the pressure-sensitive adhesive production. A pressure-sensitive adhesive for an optical film which is capable of simultaneously suppressing bending and pressing after securing processability and at the same time having high durability and reworkability and having excellent handling properties in terms of manufacturing process, .

As such a pressure-sensitive adhesive, for example, Patent Document 1 discloses an acrylic copolymer obtained by copolymerizing n-butyl acrylate, a hydroxyl group-containing monomer, and other monomers and having a weight average molecular weight of 500,000 or more and 1,000,000 or less; And an acrylic copolymer, a radical generator, an isocyanate crosslinking agent and a silane coupling agent, wherein the solid content is 25% by weight or more and the solvent is 75% by weight or less and the B- Has a viscosity of 8 Pa · s or less.

Patent Document 2 discloses a pressure-sensitive adhesive composition for an optical film containing a (meth) acrylic copolymer and a solvent, wherein the (meth) acrylic copolymer does not contain a carboxyl group-containing monomer as a monomer unit and is selected from alkyl (meth) Containing monomer and a hydroxyl group-containing monomer and having a weight average molecular weight of 300,000 to 1,200,000, a solid content of the (meth) acrylic copolymer of not less than 20% by weight and a content of the solvent of not more than 80% by weight .

Patent Document 3 discloses a pressure-sensitive adhesive composition for an optical film containing a (meth) acrylic copolymer and a solvent, wherein the (meth) acrylic copolymer is selected from the group consisting of alkyl (meth) acrylate, a polymerizable aromatic ring-containing monomer, And has a weight average molecular weight of 300,000 to 1,200,000, a solid content of the (meth) acrylic copolymer of 20% by weight or more, and a content of the solvent of 80% by weight or less.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2011-057794

[Patent Document 2] Japanese Unexamined Patent Publication No. 12040578

[Patent Document 3] Japanese Unexamined Patent Publication No. 12040579

However, the inventors of the present invention have found that even if the pressure-sensitive adhesive composition described in the above Patent Documents 1 to 3 is used, the durability in a severe environment (high temperature, high humidity, heat shock (heat shock) (Workability), or light leakage may occur in some cases. In addition, it has been found that the above-mentioned durability, reworkability, and light leakage are sufficient It has been found that the occurrence of warping and pressing can not be suppressed in some cases.

The present invention has been made in view of the above circumstances. It is an object of the present invention to provide a pressure-sensitive adhesive composition for an optical film which is excellent in durability in a harsh environment (high temperature, high humidity, heat shock) And to provide a means capable of sufficiently suppressing light leakage and further suppressing both warping and depression.

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, they have found out what can solve the above problems by a pressure-sensitive adhesive composition having a specific constitution and have completed the present invention.

In other words, the present invention is a pressure-sensitive adhesive composition for an optical film comprising a (meth) acrylate copolymer (A), a peroxide (B), a crosslinking agent (C) other than peroxide, and a solvent (D) (B) is not less than 2.0 parts by mass and not more than 10 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A), the crosslinking agent (C) other than the peroxide does not contain a block isocyanate compound, The latex copolymer (A) has a weight average molecular weight of 300,000 or more and 1,200,000 or less as measured by gel permeation chromatography (GPC), and the solid content of the (meth) acrylate copolymer (A) Wherein the content of the solvent (D) in the pressure-sensitive adhesive composition for optical films is 20 mass% or more with respect to the total mass of the pressure-sensitive adhesive composition for optical films, Is 80 mass% or less based on the mass of the pressure-sensitive adhesive composition for an optical film, and has a viscosity of 200 mPa s or more and 5000 mPa s or less at 23 deg. C as measured by a B-type viscometer (number of revolutions: 20 rpm)

The present invention also provides a pressure-sensitive adhesive composition for an optical film comprising a (meth) acrylate copolymer (A), a peroxide (B), a crosslinking agent (C) other than peroxide, and a solvent (D) Wherein the crosslinking agent (C) other than the peroxide has no block isocyanate compound, and the (meth) acrylate copolymer (A) has a half-life half-life temperature of not less than 80 ° C and not more than 125 ° C, (Meth) acrylate copolymer (A) in the pressure-sensitive adhesive composition for an optical film is 20 mass% or more based on the total mass of the pressure-sensitive adhesive composition for an optical film, , And the content of the solvent (D) in the pressure-sensitive adhesive composition for an optical film is 80 mass% or less based on the total mass of the pressure-sensitive adhesive composition for an optical film, The viscosity of the pressure-sensitive adhesive composition for an optical film is not less than 200 mPa · s and not more than 5000 mPa · s at 23 ° C. as measured by a B-type viscometer (number of revolutions: 20 rpm)

According to the present invention, a pressure-sensitive adhesive composition for an optical film is provided which has satisfactory processability and is excellent in durability under severe environments (high temperature, high humidity, heat shock) (anti-foaming property at high temperature, peeling and peeling from an adherend under high temperature and high humidity) And the workability (workability), as well as a sufficient suppression of light leakage and further suppressing both warping and pressing can be provided.

Hereinafter, embodiments for carrying out the present invention will be described.

[Pressure sensitive adhesive composition for optical film]

The pressure sensitive adhesive composition for an optical film according to the first embodiment of the present invention comprises a (meth) acrylate copolymer (A), a peroxide (B), a crosslinking agent (C) other than a peroxide, and a solvent (D) The content of the peroxide (B) is more than 2.0 parts by mass and not more than 10 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A), and the crosslinking agent (C) other than the peroxide does not contain a block isocyanate compound, The (meth) acrylate copolymer (A) has a weight average molecular weight by gel permeation chromatography (GPC) of 300,000 or more and 1,200,000 or less, and the (meth) acrylate copolymer (A) ) Is at least 20% by mass with respect to the total mass of the pressure-sensitive adhesive composition for an optical film, and the content of the solvent (D) in the pressure- Is 80 mass% or less based on the total mass of the composition, and has a viscosity of 200 mPa 占 퐏 or more and 5000 mPa 占 퐏 or less at 23 占 폚 as measured by a B-type viscometer (revolution speed of 20 rpm) of the pressure-

The pressure sensitive adhesive composition for an optical film according to the second embodiment of the present invention comprises a (meth) acrylate copolymer (A), a peroxide (B), a crosslinking agent (C) other than a peroxide and a solvent (D) Wherein the peroxide (B) has a half-life temperature for one minute of from 80 ° C to 125 ° C, the crosslinking agent (C) other than the peroxide does not contain a block isocyanate compound and the (meth) acrylate copolymer (A) (A) in the pressure-sensitive adhesive composition for an optical film has a weight-average molecular weight of not less than 300,000 and not more than 1,200,000 as measured by chromatography (GPC), and the content of solids of the pressure- Wherein the content of the solvent (D) in the pressure-sensitive adhesive composition for an optical film is 80 mass% or less based on the total mass of the pressure-sensitive adhesive composition for an optical film, The viscosity of the pressure-sensitive adhesive composition for an optical film is from 200 mPa 占 퐏 to 5000 mPa 占 퐏 at 23 占 폚 as measured by a B-type viscometer (number of revolutions: 20 rpm).

According to the pressure-sensitive adhesive composition for an optical film of the present invention having such a constitution, the durability in a severe environment (high temperature, high humidity, thermal shock) after peeling of the workability (peeling from the object to be delivered under high temperature and high humidity, Peeling and the like) and reworkability (workability), as well as to sufficiently suppress light leakage, and to suppress both warping and pressing.

Hereinafter, each component constituting the pressure-sensitive adhesive composition for an optical film according to the present invention will be described in order.

In the present specification, " (meth) acrylate " is a general term for acrylate and methacrylate. (Meth) acrylic acid and the like are also collectively referred to as a compound having "meta" and a compound having no "meta" in the name. The term "(meth) copolymer (A)" is also referred to as "copolymer (A)".

≪ (Meth) acrylate copolymer (A) >

The pressure-sensitive adhesive composition for an optical film according to the present invention essentially comprises a (meth) acrylate copolymer (A). The adhesiveness (stickiness) is exhibited by the copolymer (A) reacting with the cross-linking agent (C) other than the peroxide (B) and / or the peroxide to be described later to form a cross-linking structure.

The weight average molecular weight (Mw) of the copolymer (A) influencing the present invention by gel permeation chromatography (GPC) is 300,000 or more and 1,200,000 or less. If the weight-average molecular weight (Mw) is less than 300,000, the pressing occurs, and durability at high temperature and reheat property after heating deteriorate. On the other hand, when the weight average molecular weight exceeds 1.2 million, warpage occurs.

The weight average molecular weight (Mw) of the copolymer (A) by gel permeation chromatography (GPC) is preferably from 300,000 or more to less than 1,000,000, more preferably from 400,000 or more to 900,000 or less, More preferable. When the Mw of the copolymer (A) is within the above range, the molecular weight of the component (A) is small by controlling the solids content and the amount of the solvent containing the component (A) and the viscosity of the pressure-sensitive adhesive composition, (A), which is conventionally in the above-mentioned range, is used to form a network by forming a network by crosslinking with a crosslinking agent (C), so that if the shrinkage of the polarizing plate is increased at high temperature, It was found that there was a remarkable effect that the peeling became hard to be done. In addition, the effect of inhibiting the occurrence of warp is excellent due to the effect of the low molecular weight of the component (A). In addition, the effect of greatly lowering the productivity at the time of coating is also excellent due to the effect of lowering the molecular weight of the component (A) and controlling the viscosity. From the viewpoint that the balance of the effect of suppressing the occurrence of warping and pressing is particularly good, in addition to the durability (detachment inhibiting effect) in such a harsh environment and the effect of greatly improving the productivity at the time of coating. The weight average molecular weight (Mw) of the copolymer (A) which influences the present invention can be determined by appropriately adjusting the reaction conditions such as the type and / or amount of the polymerization initiator used in the polymerization reaction described later, the reaction temperature, It can be easily controlled.

The number average molecular weight (Mn) of the copolymer (A) influencing the present invention by gel permeation chromatography (GPC) is not particularly limited. However, in addition to a significant improvement in durability and productivity at the time of coating, Is preferably from 50,000 to 400,000 or less, more preferably from 70,000 or more to 300,000 or less, and particularly preferably from 80,000 or more to 200,000 or less. The number average molecular weight (Mn) of the copolymer (A) influencing the present invention can be controlled easily by those skilled in the art by suitably controlling the polymerization initiator used in the polymerization reaction described later, the reaction temperature such as the reaction temperature and the reaction time, can do.

The degree of dispersion (Mw / Mn) of the copolymer (A) affecting the present invention is not particularly limited, but the durability and reworkability are both satisfied. In addition to the effect of significantly improving the productivity at the time of coating, More preferably from 2.0 to 20, more preferably from 2.5 to 15, still more preferably from 3.0 to 10, from the viewpoint that the balance between the effect of suppressing the generation of stress and the effect of suppressing the pressing is particularly good.

On the other hand, the weight average molecular weight (Mw), number average molecular weight (Mn) and dispersion degree (Mw / Mn) of the copolymer (A) can be measured by gel permeation chromatography (GPC) Can be measured by the method described.

The constituent unit constituting the copolymer (A) in the present invention is not particularly limited, but (a1) a constituent unit derived from an alkyl (meth) acrylate monomer (hereinafter also referred to simply as " component (a1) (Hereinafter also referred to simply as " component (a2) ") and (a3) a structural unit derived from a monomer having a carboxyl group And at least one kind of structural unit selected from the group consisting of the following structural units. In other words, the copolymer (A) affecting the present invention preferably comprises component (a1) and component (a2); It is also preferred to include component (a1) and component (a3); In addition, it is also preferable to include the component (a1), the component (a2), and the component (a3).

On the other hand, in the present specification, for example, " the copolymer X includes a constituent unit derived from monomer Y1 and a constituent unit derived from monomer Y2 " means that the monomer Y1 and the monomer Y2. ≪ / RTI >

Hereinafter, each monomer-derived constituent unit capable of constituting the copolymer (A) affecting the present invention will be described in order.

[(A1) Structural unit derived from alkyl (meth) acrylate monomer]

The copolymer (A) which influences the present invention preferably contains (a1) a constituent unit derived from an alkyl (meth) acrylate monomer (hereinafter also referred to simply as "component (a1)"). It is considered that such a component (a1) has the significance of ensuring the tackiness and securing the basic characteristics by being included as the constituent unit of the (meth) acrylate copolymer (A) affecting the present invention.

The structure of the alkyl (meth) acrylate monomer in the present invention is not particularly limited, and is not particularly limited as long as the alkyl group is introduced into the ester moiety of the (meth) acrylate.

The number of carbon atoms of the alkyl group to be involved is not particularly limited, but is preferably 1 to 20, more preferably 1 to 12, and more preferably 1 to 10, from the viewpoints of versatility, More preferably from 1 to 8, and particularly preferably from 1 to 6, inclusive. The alkyl group may be linear, branched or cyclic, but is preferably straight-chain or branched from the viewpoint of lowering the glass transition temperature. On the other hand, when the alkyl group is cyclic, the number of carbon atoms is 3 or more.

Examples of the alkyl group to be bonded include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, Hexyl group, cyclohexyl group, 1-methylcyclohexyl group, n-heptyl group, 2-heptyl group, 3-heptyl group, isoheptyl group, t- A heptadecyl group, a hexadecyl group, a heptadecyl group, a hexadecyl group, a heptadecyl group, a heptadecyl group, a heptadecyl group, a heptadecyl group, a heptadecyl group, a heptadecyl group, Octadecyl group and the like. Particularly, a methyl group, an n-butyl group, an n-hexyl group, a 2-ethylhexyl group, a nonyl group, and an isononyl group are preferable from the viewpoint of ensuring adhesion and securing basic characteristics.

Specific examples of the alkyl (meth) acrylate monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (Meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate and cyclohexyl (meth) acrylate. Of these, methyl (meth) acrylate and n-butyl (meth) acrylate are preferable from the viewpoints of improvement of heat durability and adhesion (in particular, releasability). On the other hand, the component (a1) may be used alone or in combination of two or more.

The content of the component (a1) in the copolymer (A) affecting the present invention (the amount of the alkyl (meth) acrylate monomer as the starting monomer) is not particularly limited, (Meth) acrylate copolymer (A) is preferably from 64.5 mass% to less than 99.5 mass%, more preferably from 80 mass% or more to 99 mass% or less with respect to 100 mass% By mass or less, more preferably 85% by mass or more and 99% by mass or less. In the present specification, the "total amount of the constituent units constituting the (meth) acrylate copolymer (A)" in the present specification is 100% by mass, Means that the total amount of the monomers is 100% by mass.

[(A2) a structural unit derived from a (meth) acrylate monomer having a hydroxy group]

The copolymer (A) which influences the present invention preferably comprises (a2) a structural unit derived from a (meth) acrylate monomer having a hydroxy group (hereinafter also referred to simply as "component (a2)"). It is considered that such a component (a2) is rich in reactivity with an intermolecular crosslinking agent and is included as a constituent unit of the copolymer (A) according to the present invention, thereby improving the cohesiveness and heat resistance of the pressure-sensitive adhesive layer described later. Further, according to the studies of the present inventors, it has been found that a part of the component (a2) of the copolymer (A) can react with the crosslinking agent (C) other than the peroxide which influences the present invention and the crosslinking density of the pressure- The layer becomes firm and the amount of deformation of the pressure-sensitive adhesive layer at the time of re-peeling becomes small. As a result, the adhesive force is reduced to obtain a favorable reworkability, and peeling can be suppressed in durability. Furthermore, it has been found that the occurrence of warping and pressing can be suppressed by setting the weight average molecular weight of the copolymer (A), the viscosity of the composition, and the like within the range of the present invention.

The structure of the (meth) acrylate monomer having a hydroxy group in the present invention is not particularly limited and is not particularly limited as long as it is a form in which a hydroxy group is introduced into a part of the (meth) acrylate monomer.

Specific examples of the (meth) acrylate monomer having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,6-hexanediol mono Tri (meth) acrylate, trimethylolethane di (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, Hydroxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-hydroxybutyl Methyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, cyclohexanedimethanol monoacrylate, and the like. Further, alkyl glycidyl ether, aryl glycidyl ether, glycidyl And the like can be mentioned the glycidyl group-containing compound and a (meth) compound obtained by the addition reaction of acrylic acid, such as methacrylate. Among them, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate and the like are preferable from the viewpoint of efficiently functioning as a crosslinking point when a cross- Acrylamide and cyclohexanedimethanol monoacrylate are preferable, and 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are more preferable. On the other hand, these components (a2) may be used alone or in combination of two or more.

The content of the component (a2) in the copolymer (A) affecting the present invention (the amount of the (meth) acrylate monomer having a hydroxyl group as the starting monomer) By mass, more preferably not less than 0.6% by mass and not more than 5% by mass, and further preferably not less than 1% by mass and not more than 5% by mass, based on 100%

[(A3) a structural unit derived from a monomer having a carboxyl group]

In the present invention, the copolymer (A) preferably contains (a3) a structural unit derived from a monomer having a carboxyl group (hereinafter also referred to simply as " component (a3) "). Such component (a3) can contribute mainly to ensuring durability and adhesion to the liquid crystal panel in the pressure-sensitive adhesive composition for an optical film.

In the present invention, the structure of the monomer having a carboxyl group is not particularly limited, and any structure may be used as long as it contains a carboxyl group and a polymerizable unsaturated bond in its structure.

Specific examples of the monomer having a carboxyl group include (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, anhydrous fumaric acid, crotonic acid, itaconic acid, itaconic anhydride, misteroolic acid, palmitoleic acid and oleic acid. . Among them, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, anhydrous fumaric acid, crotonic acid, itaconic acid, and itaconic anhydride are preferable from the viewpoint of good copolymerization with other (meth) Is more preferable. On the other hand, these components (a3) may be used alone or in combination of two or more.

The content of the component (a3) in the copolymer (A) affecting the present invention (the amount of the monomer having a carboxyl group as the starting monomer) is not particularly limited, but from the viewpoint of ensuring durability and preventing deterioration of the workability Is more preferably 0 mass% to 10 mass%, more preferably 0 mass% to 8 mass%, and most preferably 1 mass% to 100 mass% And more preferably not less than 5% by mass.

[(A4) a structural unit derived from a (meth) acrylate monomer having an aromatic ring]

The copolymer (A) which influences the present invention preferably further comprises a constituent unit derived from a (meth) acrylate monomer having an aromatic ring (hereinafter also referred to simply as " component (a4) ") . Such component (a4) can contribute mainly to suppression of light leakage in the pressure-sensitive adhesive composition for an optical film.

The structure of the (meth) acrylate monomer having an aromatic ring in the present invention is not particularly limited, and any structure may be used as long as it contains an aromatic ring (aromatic ring) and a (meth) acrylate group in its structure. The aromatic ring is not particularly limited, and examples thereof include a benzene ring, a naphthalene ring and a biphenyl ring.

Specific examples of the (meth) acrylate monomer having an aromatic ring include benzyl (meth) acrylate, phenyl (meth) acrylate, o-phenylphenol (meth) acrylate, phenoxy (meth) acrylate, (Meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide modified nonylphenyl (Meth) acrylate, phenol ethylene oxide modified (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) (Meth) acrylate, and polystyryl (meth) acrylate; (Meth) acrylate, 2-naphthoxyethyl acrylate, 2- (4-methoxy-1-naphthoxy) ethyl Having a naphthalene ring; And a biphenyl ring such as biphenyl (meth) acrylate. Of these, benzyl (meth) acrylate and phenoxyethyl (meth) acrylate are preferable from the standpoint of suppressing light leakage and ensuring durability. On the other hand, these components (a4) may be used alone or in combination of two or more.

The content of the component (a4) in the copolymer (A) affecting the present invention (the amount of the (meth) acrylate monomer having an aromatic ring as the starting monomer) is not particularly limited, but the light leakage can be sufficiently suppressed (Meth) acrylate copolymer (A) is preferably 0 mass% or more and 30 mass% or less, more preferably 10 mass% or more and 20 mass% or less, based on 100 mass% And more preferably not more than 1 mass%.

[(A5): a structural unit derived from a monomer other than the components (a1) to (a4)]

The copolymer (A) which influences the present invention is a copolymer comprising a constituent unit derived from a monomer other than the components (a1) to (a4) capable of copolymerizing with the above-mentioned components (a1) to Quot; component (a5) ").

As the raw material monomer of the component (a5), known monomers can be used so long as the effect of the present invention is not impaired.

Examples of the raw monomer of the component (a5) include acrylic monomers having an epoxy group such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; Acrylate having an amino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate and (meth) acryloyloxyethyltrimethylammonium chloride. Monomers; (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (Meth) acrylic monomers having an amide group such as methoxymethyl (meth) acrylamide, N, N-methylenebis (meth) acrylamide, dimethylaminopropyl (meth) acrylamide and diacetone (meth) acrylamide; Acrylate such as 2-methacryloyloxyethyldiphenylphosphato (meth) acrylate, trimethacryloyloxyethylphosphato (meth) acrylate, triacryloyloxyethylphosphato (meth) acrylate and the like (Meth) acrylic monomer having a phosphoric acid group; (Meth) acrylic monomers having sulfonic acid groups such as sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate and sodium 2-acrylamide-2-methylpropanesulfonate; (Meth) acrylic monomers having a urethane group such as urethane (meth) acrylate; Vinyltriethoxysilane, vinyltris (? -Methoxyethyl) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyltriethoxysilane, vinyltriethoxysilane, A vinyl-based monomer having a silane group; (Meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentyl (meth) acrylate, dicyclopentenyl (meth) acrylate, (Meth) acrylate, (meth) acryloylmorpholine, and the like can be used. Specific examples of the (meth) acrylic acid esters include, but are not limited to, .

Also, (meth) acrylate monomers having an alkoxyalkyl group or an alkylene oxide group as a raw material monomer of the component (a5) may be preferably used.

Examples of the (meth) acrylate monomer having an alkoxyalkyl group or an alkylene oxide group include methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (Meth) acrylate, butoxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate; (Meth) acrylate, methoxy-diethylene glycol (meth) acrylate, ethoxy-triethylene glycol (meth) acrylate, methoxy-triethylene glycol (Meth) acrylates such as diethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, 2-ethylhexyloxy-diethylene glycol = 4 to 10), methoxydipropylene glycol (meth) acrylate, and 2-ethylhexyl-diglycol acrylate.

On the other hand, the above-mentioned monomers may be used singly or in combination of two or more. From the viewpoints that the reaction with the crosslinking agent to be described later can be easily controlled when producing the (meth) acrylate copolymer (A) influencing the present invention, from the viewpoint that the molecular weight is not increased, ) Preferably contains no olefinic monomer such as ethylene or propylene.

In the copolymer (A) affecting the present invention, the glass transition temperature of the homopolymer in the components (a1) to (a5) of the component (a1) (Hereinafter referred to as simply " component (a ') ") (hereinafter referred to also simply as component (a')) It is possible to secure the rigidity of the pressure-sensitive adhesive layer and soften at a heating durability test temperature of 80 deg. C or more at which the warpage is further caused to give stress relieving property to the pressure-sensitive adhesive layer, Is excellent in that it has good polymerizability with a rate monomer, improves durability and adhesive force (in particular, reworkability), and suppresses the occurrence of warping and pressing.

((Meth) acryl-based (co) polymer (H))

In the pressure-sensitive adhesive composition for an optical film according to the present invention, unlike the copolymer (A), a (meth) acrylic copolymer having a weight average molecular weight (Mw) smaller than that of the copolymer (A) (Co) polymer (H) (hereinafter also simply referred to as " (co) polymer (H) ") containing a monomer-derived constituent unit. Such a (co) polymer (H) is similar to the copolymer (A), but is present as an acrylic resin having a low molecular component such as a high softening point resin (G) described later. Therefore, among the pressure-sensitive adhesive layers formed by using the pressure-sensitive adhesive composition for optical films containing the (co) polymer (H), the (co) polymer (H) can move freely and therefore the pressure- It is excellent in that it becomes easy to do. Unlike the high softening point resin (G), the (co) polymer (H) is an acrylic component such as the copolymer (A), and therefore, when compatibility is good and the pressure sensitive adhesive layer contains the high softening point resin (G) (Preferably, it is not cloudy) as compared with the case where it is cloudy. Therefore, by further including the above-mentioned (co) polymer (H), it is possible to secure the rigidity of the pressure-sensitive adhesive layer at room temperature requiring pressure resistance by providing all the characteristics as described above, At a test temperature of 80 deg. C or more, the pressure-sensitive adhesive layer is excellent in stress relaxation property and warpage can be suppressed.

(Weight average molecular weight of (co) polymer (H)

The weight average molecular weight (Mw) of the (co) polymer (H) is not particularly limited as long as the weight average molecular weight (Mw) is smaller than that of the copolymer (A), but is preferably 500 or more and 100,000 or less, more preferably 800 or more and 80,000 or less And more preferably 1,000 or more and 50,000 or less. The (co) polymer (H) having a molecular weight in the above range is similar to the copolymer (A) in its constituent unit but is present separately as an acrylic resin of a low molecular component. Therefore, among the pressure-sensitive adhesive layers formed using the pressure-sensitive adhesive composition for optical films containing the (co) polymer (H), the (co) polymer (H) can move freely and hence the pressure- Outstanding in terms of ease. Further, since the (co) polymer (H) is an acrylic component such as the copolymer (A), compatibility is good and the pressure-sensitive adhesive layer is less likely to become turbid (preferably, it is not cloudy).

The pressure-sensitive adhesive composition for an optical film of the present invention may contain the component (a ') in the copolymer (A) or may contain the above (co) polymer (H) different from the copolymer (A).

In order to efficiently exhibit the effects of the above-mentioned components (a ') and (co) polymers (H) in which the glass transition temperature of the homopolymer is 50 ° C or higher in the pressure-sensitive adhesive composition for an optical film of the present invention, The component having a temperature of 50 占 폚 or higher may be a component of the (meth) acrylate copolymer (A) or may be present in the (co) polymer (H), unlike the (meth) acrylate copolymer (A). In other words, the component (A ') may be copolymerized with the component (A') of the other (meth) acrylate copolymer, or the copolymer (A) may be polymerized with the component The (co) polymer (H) may be blended differently from the cohesion (A).

In the present invention, the structure of the (meth) acrylic monomer having a glass transition temperature of 50 占 폚 or higher of the homopolymer which can be used in the component (a ') or the (co) polymer (H) Lt; 0 > C or more.

Specific examples of the (meth) acrylic monomer constituting the (co) polymer (H) include isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (Meth) acrylamide, dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylaminopropyl (Meth) acrylamide, diacetone (meth) acrylamide, acryloylmorpholine, 2-methacryloyloxyethylphthalic acid, tetrahydrofurfuryl (meth) acrylate, methyl Ethyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2- Meta) acrylate (Meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, t- (Meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, (Meth) acrylic acid (1 to 20 carbon atoms) alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, (Meth) acrylate such as cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, aralkyl (meth) acrylate (such as benzyl (meth) acrylate) (Meth) acrylate (e.g., 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) Methyl (meth) acrylate, etc.), hydroxy group-containing (meth) acrylates (for example, (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) acrylate and the like), an alkoxy group or a phenoxy group- (Meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (Meth) acrylates such as carbitol (meth) acrylate and phenoxyethyl (meth) acrylate), epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, halogen- (For example, 2,2,2-trifluoroethyl (meth) acrylate (Meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptafluoropropyl (meth) acrylate, (Meth) acrylate), alkylaminoalkyl (meth) acrylates (e.g., dimethylaminoethyl (meth) acrylate), and the like. These (meth) acrylic monomers may be used singly or in combination of two or more.

Acrylic oligomers as the (co) polymer (H) may also be used. Specific examples of the acrylic oligomer include Arufon (registered trademark) manufactured by Toagosei, Actflow (registered trademark) manufactured by Soken Chemical Co., Ltd., BASF Japan Co., And " JONCRYL (registered trademark) ".

Specific examples of the (meth) acrylic monomer having a glass transition temperature of 50 캜 or higher of the homopolymer, which can be used in the component (a ') or the (co) polymer (H) And the glass transition temperature of the homopolymer composed of the corresponding monomer in the parentheses.

Specific examples thereof include isobornyl acrylate (94 ° C), dicyclopentenyl acrylate (120 ° C), dicyclopentanyl acrylate (120 ° C), acrylonitrile (97 ° C), acrylamide ), N-methylol acrylamide (150 DEG C), dimethylol acrylamide (119 DEG C), N-isopropylacrylamide (134 DEG C), diethylacrylamide (81 DEG C), dimethylaminopropylacrylamide ), Diacetone acrylamide (77 DEG C), acryloylmorpholine (145 DEG C), 2-methacryloyloxyethylphthalic acid (55 DEG C), methyl methacrylate (105 DEG C), ethyl methacrylate C), t-butyl methacrylate (107 캜), cyclohexyl methacrylate (66 캜), tetrahydrofurfuryl methacrylate (60 캜), benzyl methacrylate (54 캜), isobornyl methacryl (180 占 폚), dicyclopentenyloxyethyl methacrylate (50 占 폚), dicyclopentanyl methacrylate (175 ), And the like. These may be used alone or in combination of two or more.

The content of the component (a ') in the copolymer (A) affecting the present invention (the content of the (meth) acrylic monomer having a glass transition temperature of 50 캜 or higher of the homopolymer as the raw monomer) Is preferably from 0% by mass to 20% by mass, more preferably from 0.1% by mass to 15% by mass, based on 100% by mass of the total amount of the constituent units constituting the copolymer (A) Particularly preferably not less than 0.5% by mass and not more than 10% by mass.

When the content of the component (a ') is 20 mass% or less, it is preferable from the viewpoint that both the pressing and the suppression of warpage become easier.

The content of the (co) polymer (H) that influences the present invention is preferably 20% by mass or less based on the total mass of the pressure-sensitive adhesive composition for optical film from the viewpoint of more effectively showing the effect of the present invention, Is not less than 0.1 mass% and not more than 15 mass%, particularly preferably not less than 0.5 mass% nor more than 10 mass%. When the content of the (co) polymer (H) is 20 mass% or less, the advantages such as easy suppression and warpage can be obtained.

The glass transition temperature of the homopolymer may be 50 DEG C or higher, but it is preferably 50 DEG C to 200 DEG C, more preferably 50 DEG C or more and 150 DEG C or less, from the viewpoint of easily balancing the suppression of compression and warpage And more preferably 60 ° C or more and 120 ° C or less. The glass transition temperature is a value measured by differential scanning calorimetry of the homopolymer (homopolymer).

The above-mentioned copolymer (A) and (co) polymer (H) may be used alone or in combination of two or more.

[Process for producing (meth) acrylate copolymer (A)]

Next, the production method of the copolymer (A) will be described. In the present invention, the production method of the copolymer (A) is not particularly limited and may be a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, a half-object suspension polymerization method, , Spray polymerization, and the like can be employed. Examples of polymerization control methods include an adiabatic polymerization method, a temperature control polymerization method, and an isothermal polymerization method. As the polymerization initiator, any of a thermal polymerization initiator and a photopolymerization initiator may be used. In addition to the method of initiating polymerization by a polymerization initiator, a method of initiating polymerization by irradiating an active energy ray such as radiation, electron beam, ultraviolet ray or the like may be employed. Among them, a solution polymerization method employing a thermal polymerization initiator or a bulk polymerization method using a photopolymerization initiator is more preferable since the molecular weight can be easily controlled and the amount of impurities can be reduced.

In the solution polymerization method using a thermal polymerization initiator, it can be obtained by adding a thermal polymerization initiator to a monomer solution serving as a raw material of the copolymer (A), for example, a raw monomer solution comprising the monomer, and performing a polymerization reaction. More specifically, ethyl acetate, toluene, methyl ethyl ketone, acetone or the like is employed as a solvent, and 0.01 part by mass or more and 1 part by mass or less of a thermal polymerization initiator is added to 100 parts by mass of the total amount of the starting monomers, For example, at a reaction temperature of 40 ° C to 90 ° C (or 60 ° C to 90 ° C) for 3 hours to 10 hours.

Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2-methylbutyronitrile), azobiscyanovaleric acid, 2,2 ' Azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis [N- 2-methylpropionamide], 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis [2- ) Propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfato hydrate, Dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, 2,2'-azobis [2- Azolin-2-yl) propane], 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride, 2,2'- - (2-hydroxyethyl) propionamide; t-butyl peroxybenzoate, t-butyl peroxy-2-ethyl hexanoate, di-t-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, t-butyl Organic peroxides such as hydroperoxide; Inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. These thermal polymerization initiators may be used alone or in combination of two or more.

In the bulk polymerization method using a photopolymerization initiator, for example, a raw monomer and a photopolymerization initiator are added, and an active energy ray is irradiated under a nitrogen atmosphere at a reaction start temperature of 20 ° C or higher and 35 ° C or lower. And then the reaction is stopped by, for example, introducing air into the reaction system at a stage where the temperature in the reaction system has risen from 5 ° C or more and 15 ° C or less from the reaction start temperature to obtain the copolymer (A).

Examples of the active energy ray which can be used in the bulk polymerization method include ultraviolet rays, laser rays, alpha rays, beta rays, gamma rays, X rays and electron beams. However, Ultraviolet radiation can be preferably employed. More preferably, ultraviolet rays having a wavelength of 200 nm or more and 400 nm or less can be used. Ultraviolet rays can be irradiated using a light source such as a high-pressure mercury lamp, a microwave-excited lamp, a chemical lamp, or a black light. The roughness is preferably in the 3.2mW / cm ² or less than 5.6mW / cm ^2.

Examples of the photopolymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethylketal, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1- (4- Methyl-1- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-hydroxy- Acetophenones such as phenylpropan-1-one; Benzophenones including benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone; Benzoin ethers such as benzoin propyl ether and benzoin ethyl ether; Thioxanthones such as 4-isopropylthioxanthone; 1-hydroxycyclohexyl phenyl ketone, xanthone, flowrenone, camphorquinone, benzaldehyde, and anthraquinone. These photopolymerization initiators may be used singly or in combination of two or more.

Examples of commercial products include Irgacure (registered trademark) 184, 819, 907, 651, 1700, 1800, 819, 369, 261, DARACURE (registered trademark) TPO, 1173 (manufactured by BASF Japan KK), Ezacure KIP150, TZT (manufactured by DKSH Japan KK), Kayacure BMS, DMBI (manufactured by Nippon Kayaku Co., Ltd.) And the like.

The amount of the photopolymerization initiator to be used is preferably 0.0005 parts by mass or more and 1 part by mass or less, more preferably 0.002 parts by mass or more and 0.5 parts by mass or less, based on 100 parts by mass of the total amount of the raw monomers.

A chain transfer agent may also be used to control the molecular weight of the copolymer (A). For example, there may be mentioned methylmercaptan, t-butyl mercaptan, decyl mercaptan, benzyl mercaptan, stearyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoacetic acid, Esters, 2-ethylhexyl thioglycol, and octyl thioglycolate; Alcohols such as methanol, ethanol, propanol, n-butanol, isopropanol, t-butanol, hexanol, benzyl alcohol and allyl alcohol; Halogenated hydrocarbons such as chloroethane, fluoroethane and trichlorethylene; Carbonyls such as acetone, methyl ethyl ketone, cyclohexanone, acetophenone, acetaldehyde, propionaldehyde, n-butylaldehyde, furfural, benzaldehyde and the like; Methyl-4-cyclohexene-1,2-dicarboxylic anhydride, and? -Methylstyrene. These chain transfer agents may be used alone or in combination of two or more.

On the other hand, the production method in the case of synthesizing the (co) polymer (H) is the same as the production method of the copolymer (A) except that the type and amount of the monomer and the amount of the polymerization initiator used are changed.

≪ Peroxide (B) >

The pressure-sensitive adhesive composition for an optical film of the present invention comprises a peroxide (B) as an essential component. In the present specification, "peroxide" means a compound having a peroxide structure "-O-O-" in the molecular structure.

In the present invention, the peroxide (B) may function as a crosslinking agent, may function as a polymerization initiator, or may have both of them.

In the present invention, the first embodiment in which the content of the peroxide (B) is from 2.0 parts by mass or more to 10 parts by mass or less based on 100 parts by mass of the copolymer (A) and the second embodiment wherein the peroxide (B) Two embodiments will be described.

≪ First Embodiment >

The peroxide (B) that can be employed in the first embodiment is not particularly limited, and known materials can be used.

As the peroxide (B) that can be used in the present embodiment, the half-life temperature for one minute is preferably 80 占 폚 or higher and 160 占 폚 or lower in view of productivity and stability, more preferably 80 占 폚 or higher and 140 占 폚 or lower, More preferably 90 deg. C or more and 125 deg. C or less.

The term " half-life period of peroxide " means an index indicating the rate of decomposition of peroxide, which means the time until the residual amount of peroxide becomes half. The decomposition temperature for obtaining a half-life at a certain time or the half-life time at a certain temperature is described in the manufacturer's catalog. For example, the organic peroxide catalog No. 9 issued by NOF CORPORATION (May 2003) Lt; / RTI >

Examples of such peroxides include diisopropyl peroxydicarbonate having a half-life temperature of 88.3 DEG C for 1 minute, a temperature within the brackets representing a half-life temperature for 1 minute, di (2-ethylhexyl) peroxydicarbonate (90.6 DEG C) t-butylcyclohexyl) peroxydicarbonate (92.1 占 폚), di-sec-butylperoxydicarbonate (92.4 占 폚), t-butylperoxyneodecanoate (103.5 占 폚), t-hexyloxypivalate T-butyl peroxypivalate (110.3 占 폚), dilauryl peroxide (116.4 占 폚), bis-n-octanoyl peroxide (117.4 占 폚), 1,1,3,3-tetramethylbutyl (Benzoyl peroxide) (130.0 占 폚), dibenzoyl peroxide and benzoyl m-methyl (benzoyl peroxide) at 130.0 占 폚, peroxy-2-ethylhexanoate A mixture of benzoyl peroxide and m-toluyl peroxide (131.1 ° C), and t-butyl peroxybutyrate (136.1 ° C). Of these, diisopropyl peroxy dicarbonate, di (4-t-butylcyclohexyl) peroxy dicarbonate and t-butyl peroxy neodecanoate can be preferably used. These may be used alone or in combination of two or more in view of controlling the reactivity. When two or more of them are used in combination, a combination of di (4-t-butylcyclohexyl) peroxy dicarbonate and dilauryl peroxide is preferable. The peroxide (B) may be a synthetic product or a commercially available product.

Examples of commercially available products of peroxides (B) that can be used in the first embodiment include those sold under the trademark " PEROIL (registered trademark; hereinafter the same) IB (85.1 DEG C) Perodil NPP "(94.0 ° C)," Peroyl IPP "(88.3 ° C)," Peroyl SBP "(92.4 ° C)," Paokuta (registered trademark) (92.4 占 폚), Peruyol TCP (92.1 占 폚), Peruyol OPP (90.6 占 폚), Perhexyl (registered trademark) ND (100.9 占 폚), Perbutyl Perfluoro NHP "(104.6 ° C)," Perhexyl PV "(109.1 ° C)," Perbutyl PV "(110.3 ° C)," Peroyl 355 "(112.6 ° C) , "Peroil L" (116.4 ° C), "Paokuta O" (124.3 ° C), "Peroil SA" (131.8 ° C), "Perhexa (Registered trademark, hereinafter the same) PMB (128.2 占 폚), perbutyl O (134.0 占 폚), Naipa B (131.1 ° C), "Nipa BW" (130.0 ° C), "Nipa BMT-K40" (131.1 ° C), "Nipa BMT-M" (131.1 ° C) and "Perhexa MC" , "Perhexa TMH" (147.1 ° C), "Perhexa HC" (149.2 ° C), "Perhexa C" (153.8 ° C) Hexyl I "(155.0 ° C)," perbutyl L "(159.4 ° C)," perbutyl I "(158.8 ° C)," perhexa 25Z " Hexa 22 " (159.9 占 폚).

In the first embodiment, the content of the peroxide (B) is 2.0 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the copolymer (A). When the content of the peroxide (B) is 2.0 parts by mass or less, it can not be said that it is sufficient to improve the heating durability at high temperature. On the other hand, if it exceeds 10 parts by mass, the crosslinking density becomes excessively high to deteriorate the durability, The stability of the liquid may deteriorate.

The content of the peroxide (B) is preferably 2.0 parts by mass or more and 5.0 parts by mass or less, more preferably 2.0 parts by mass or more and 3.0 parts by mass or less, based on 100 parts by mass of the copolymer (A) from the viewpoint of satisfying the heating durability at high temperature. Is more preferable.

≪ Second Embodiment >

The peroxide (B) that can be employed in the second embodiment has a half-life temperature for one minute of 80 ° C or more and 125 ° C or less. Within this range, productivity and stability are excellent. The one-minute half-life temperature is preferably 85 ° C or more and 125 ° C or less, more preferably 90 ° C or more and 120 ° C or less.

Specific examples of peroxides (B) that can be used in the second embodiment include diisopropyl peroxydicarbonate (88.3 占 폚), di (2-ethylhexyl) peroxydicarbonate (90.6 占 폚) butyl peroxy dicarbonate (92.1 占 폚), di-sec-butyl peroxydicarbonate (92.4 占 폚), t-butyl peroxyneodecanoate (103.5 占 폚), t- (109.1 占 폚), t-butyl peroxypivalate (110.3 占 폚), dilauryl peroxide (116.4 占 폚), bis-n-octanoyl peroxide (117.4 占 폚), 1,1,3,3- And methyl butylperoxy-2-ethylhexanoate (124.3 占 폚).

Examples of commercially available products of peroxides (B) that can be used in the second embodiment include "PEROIL (registered trademark, hereinafter the same) IB" (85.1 ° C), "PARK Mill Perooyl NPP "(94.0 ° C)," peroyl IPP "(88.3 ° C)," perroyl SBP "(92.4 ° C)," Paokuta ) ND (92.4 占 폚), Peruyol TCP (92.1 占 폚), Peruyol OPP (90.6 占 폚), Perhexyl Perfluoro NHP "(104.6 ° C)," Perhexyl PV "(109.1 ° C)," Perbutyl PV "(110.3 ° C) and" Peroyl 355 "(112.6 ° C ), "Peroil L" (116.4 ° C), "Paokuta O" (124.3 ° C), and "Perhexa (registered trademark)" (118.8 ° C).

The content of the peroxide (B) in the second embodiment is not particularly limited, but is preferably 0.05 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more, based on 100 parts by mass of the copolymer (A) Mass part or less, more preferably 0.2 mass part or more and 3 mass parts or less. Such a range is excellent in securing durability and capable of achieving both of warpage suppression and compression suppression.

≪ Crosslinking agent (C) other than peroxide >

The pressure-sensitive adhesive composition for an optical film of the present invention contains a cross-linking agent (C) other than a peroxide as an essential component. The crosslinking agent (C) other than the peroxide reacts with the (meth) acrylate copolymer (A) to form a crosslinked structure, which can contribute mainly to adhesiveness (tackiness) and durability in the pressure-sensitive adhesive composition for an optical film. Here, the term "other than peroxide" is used herein to distinguish it from the "peroxide (B)" described above.

In the present invention, the crosslinking agent (C) other than the peroxide does not contain a block isocyanate compound. On the other hand, "a block isocyanate compound" is an isocyanate compound protected with an isocyanate group by using a blocking agent (also referred to as "protecting group"). Conventionally, a block isocyanate compound is generally used as a curing agent for paints and the like, but requires a long time of heat treatment at a high temperature. On the other hand, Japanese Patent Application Laid-Open No. 11-132297 discloses an invention capable of curing a pressure-sensitive adhesive at a low temperature and / or a short time by using a peroxide and a block isocyanate compound in combination.

However, research by the present inventors has revealed that when the peroxide and the block isocyanate compound are used in combination, the durability of the obtainable pressure-sensitive adhesive composition may be lowered. The inventors of the present invention have found that by using the crosslinking agent (C) not containing a block isocyanate compound and the above-mentioned peroxide (B) in combination, the temperature is lower than that of the technology described in Japanese Patent Laid-Open Publication No. 2011-132297 The present inventors have found that the pressure-sensitive adhesive can be cured in a short time and that the durability of the obtained pressure-sensitive adhesive composition can also be improved, thereby completing the present invention.

In the present invention, the cross-linking agent (C) other than the peroxide may be at least one selected from the group consisting of an isocyanate cross-linking agent other than the block isocyanate compound, a carbodiimide cross-linking agent, an oxazoline cross-linking agent, an epoxy cross-linking agent, and an aziridine cross- . Hereinafter, various crosslinking agents will be described.

[Isocyanate crosslinking agent]

In the present invention, as the crosslinking agent (C) other than the peroxide, an isocyanate crosslinking agent can be preferably used. In this case, as described above, it is used in the form of an isocyanate compound which is not blocked as an isocyanate crosslinking agent.

Examples of the isocyanate-based crosslinking agent that can be preferably used in the present invention include triaryl isocyanurate, dimeric acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate 6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4- , Aromatic isocyanates such as xylene diisocyanate (XDI), tetramethylxylydene diisocyanate (TMXDI), toluidine diisocyanate (TODI), and 1,5-naphthalene diisocyanate (NDI); Aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, and norbornadiisocyanate methyl (NBDI); Cyclic diisocyanates such as trans-cyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI) and H12-MDI (hydrogenated MDI); Carboxymide-modified diisocyanates of the above diisocyanates; Or an isocyanurate-modified diisocyanate thereof. An adduct of the isocyanate compound and a polyol compound such as trimethylolpropane, and a buretecene isocyanurate of the isocyanate compound can also be preferably used.

These isocyanate-based crosslinking agents may be used in the form of a synthetic product or a commercially available product.

Examples of commercially available products include Coronito (registered trademark; hereinafter the same) L, Coronito HL, Coronito HX, Coronito 2030, Coronito 2031 (manufactured by Tosoh Corporation) Mitsui Chemicals (registered trademark), D-102, Takeakeito D-110N, Takeakeito D-131N, Takeakeito D-200, Takeakeito D- (Registered trademark, hereinafter the same) 24A-100, Terra Nato TPA-100, Terra Nato TKA-100, Terra Nato P301-75E, Terra Nato E402-90T, Terra Nato N-75, N (trade name) manufactured by Asahi Kasei Co., Ltd.), DERANATE D-101, DERANATE D- -3200, and N-3300 (or more, residential commercialized Bayer Urethane (Covestro)). Of these, preferred are Coronate L, Coronate HL, Coronate HX, Takehenate D-110N, Takeakeito D-131N, Deranate 24A-100, Deranate TPA-100.

The isocyanate crosslinking agent according to the present invention preferably contains an isocyanate compound having a number average molecular weight (Mn) of 900 or more and 10,000 or less (excluding a block isocyanate compound). By including such an isocyanate compound, a gentle crosslinking effect due to a long distance between the crosslinking points can be exhibited while suppressing the density of the crosslinking structure of the copolymer (A). This makes it possible to both suppress the foaming as heating durability and suppress the peeling. The number average molecular weight (Mn) is preferably 900 or more and 7,000 or less, more preferably 1,000 or more and 5,000 or less from the viewpoint of further exerting such effects. On the other hand, the number average molecular weight (Mn) of the isocyanate crosslinking agent can be measured by the same method as the method of measuring the weight average molecular weight of the copolymer (A) in the examples.

[Carbodiimide crosslinking agent]

In the present invention, the carbodiimide crosslinking agent is not particularly limited. However, when one example is given, a high molecular weight polycarbodiimide which can be obtained by subjecting a diisocyanate to a decarboxylic acid condensation reaction in the presence of a carbodiimidization catalyst is used do.

Examples of the diisocyanate to be provided in the decarbonation condensation reaction include 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'- Dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and tetramethylxylydene diisocyanate.

Examples of the carbodiimidation catalyst that can be employed in the decarbonation condensation reaction include 1-phenyl-2-phospholene-1-oxide, 3-methyl- Ethyl-3-methyl-2-phosphorene-1-oxide, 1-ethyl-2-phosphorene-1-oxide or its 3-phosphorene isomer and the like.

The high molecular weight polycarbodiimide may be a synthetic material or a commercially available product.

Commercially available products include, for example, Carbodite (registered trademark, hereinafter the same) series manufactured by Nisshinbo-chem. Of these, carboditlite V-01, V-03, V-05, V-07 and V-09 are preferable because they are excellent in compatibility with organic solvents.

≪ Oxazoline crosslinking agent >

In the present invention, the oxazoline crosslinking agent is not particularly limited, but an oxazoline group-containing acrylic / styrene-based polymer having a main chain composed of an acrylic skeleton or a styrene skeleton and having an oxazoline group in the side chain of the main chain thereof, And an oxazoline group-containing acrylic polymer having an oxazoline group in the side chain of the main chain. An oxazoline group-containing polymer is preferably used.

Examples of the oxazoline group include a 2-oxazoline group, a 3-oxazoline group and a 4-oxazoline group, and among them, a 2-oxazoline group is preferable.

The oxazoline group-containing polymer may have a polyoxyalkylene group in addition to the oxazoline group.

Specific examples of the oxazoline group-containing polymer include oxazoline group-containing polymers such as EPOXUROS (registered trademark; hereinafter the same) WS-300, EPOXOUS WS-500 and EPOXOUS WS-700 manufactured by NIPPON SHOKUBAI Acryl-based polymers, oxazoline group-containing acrylic / styrenic polymers such as Ephokuroz K-1000 series of Nippon Shokubai Co., Ltd. and Eposukuros K-2000 series.

[Epoxy crosslinking agent]

In the present invention, the epoxy cross-linking agent is not particularly limited, and a known epoxy cross-linking agent can be suitably employed. Examples of commercially available products include "TETRAD (registered trademark) -C", "TETRAD (registered trademark) -X" manufactured by Mitsubishi Gas Chemical Company, "ADEKA RESIN (registered trademark) EPU series" Adeka Resin (registered trademark) EPR series ", and " Celloxide (registered trademark) " These liquid epoxy resins are preferable in that the mixing operation when the pressure-sensitive adhesive composition for an optical film is produced becomes easy.

[Aziridine Crosslinking Agent]

In the present invention, the aziridine crosslinking agent is not particularly limited, but a polyfunctional aziridine compound having a plurality of aziridine rings can be used optimally. Examples of the polyfunctional aziridine compound include compounds disclosed in U.S. Patent No. 3,225,013, U.S. Patent No. 4,490,505, U.S. Patent No. 5,534,391, and JP-A No. 2003-104970.

Commercially available products of the aziridine crosslinking agent include, for example, Chemitrite (registered trademark) PZ-33 and Chemitrite (registered trademark) DZ-22E available from Nippon Shokubai Co.,

In the present invention, the cross-linking agent (C) other than the peroxide is at least one selected from the group consisting of an isocyanate-based cross-linking agent containing no block isocyanate compound, a carbodiimide based cross-linking agent, an oxazoline based cross-linking agent, Insofar as they include species, they may be used alone, or two or more species may be used in combination. When two or more kinds of crosslinking agents are used, two or more kinds of crosslinking agents of the same system (for example, two types of isocyanate crosslinking agents) may be used in combination, and one or more crosslinking agents of different types (for example, 1 type and a carbodiimide type crosslinking agent may be combined).

The content of the crosslinking agent (C) other than the peroxide in the pressure-sensitive adhesive composition for an optical film according to the present invention is not particularly limited, but is preferably 0.001 part by mass or more and 2 parts by mass or less based on 100 parts by mass of the copolymer (A) . When the content of the crosslinking agent (C) other than peroxide is 0.001 parts by mass or more, crosslinking effect can be obtained and durability can be ensured. On the other hand, when the content is 2 parts by mass or less, the pressure-sensitive adhesive layer is not excessively hardened, can do.

The content of the crosslinking agent (C) other than peroxide is more preferably 0.01 parts by mass or more and 1.5 parts by mass or less based on 100 parts by mass of the copolymer (A) from the viewpoint of further ensuring durability due to the manifestation of a crosslinking effect, And more preferably 1.0 part by mass or less.

≪ Solvent (D) >

The pressure-sensitive adhesive composition for an optical film of the present invention comprises a solvent (D). By including the solvent (D), it is possible to obtain a significant improvement in productivity at the time of coating. Examples of the solvent (D) include, but are not limited to, esters such as ethyl acetate and n-butyl acetate; Aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; Cyclic hydrocarbons such as cyclohexane and methylcyclohexane; And organic solvents such as ketones such as methyl ethyl ketone, methyl isobutyl ketone, and acetone. These solvents may be used alone or in combination of two or more.

The content of the solvent (D) in the pressure-sensitive adhesive composition for an optical film of the present invention is 80 mass% or less based on the total mass of the pressure-sensitive adhesive composition for an optical film. If the content of the solvent exceeds 80 mass%, the productivity during coating may be lowered, and the balance of the effect of suppressing the occurrence of warping and pressing may be lowered. The content of the above-mentioned solvent (D) in the pressure-sensitive adhesive composition for an optical film is preferably 30% by mass or more and 80% by mass or less, more preferably 50% by mass or more and 78% by mass or less based on the total mass of the pressure- And more preferably not less than 77% by mass. When the content is within this range, in addition to the durability and productivity at the time of coating, the balance between the effect of suppressing the occurrence of warping and the pressing is particularly good.

The solid content of the pressure-sensitive adhesive composition for an optical film of the present invention containing the copolymer (A) is 20% by mass or more based on the total mass of the pressure-sensitive adhesive composition for an optical film. When the solid content is less than 20% by mass, the productivity during coating is lowered, and the balance of the effect of suppressing the occurrence of warpage and sagging is lowered. The content of the solid content in the pressure-sensitive adhesive composition for an optical film is preferably 20 mass% or more and 70 mass% or less, more preferably 22 mass% or more and 50 mass% or less, and still more preferably 23 mass% or more and 30 mass% By mass or less. When the content is within this range, the effect of suppressing the occurrence of warping and pressing is particularly well balanced. Furthermore, since the solid content is high at the time of coating, the coating speed can be maintained at a level higher than ever, To provide a pressure-sensitive adhesive composition for an optical film which can obtain a pressure-sensitive adhesive optical film having good quality.

The solid content of the pressure-sensitive adhesive composition for an optical film of the present invention can be easily controlled by those skilled in the art by appropriately controlling the amounts of components constituting the pressure-sensitive adhesive composition for an optical film. The solid content can be measured by removing the non-solid component from the pressure-sensitive adhesive composition for an optical film (solid-liquid separation). The content of the solvent in the pressure-sensitive adhesive composition for an optical film of the present invention can also be easily controlled by those skilled in the art by appropriately controlling the amounts of components constituting the pressure-sensitive adhesive composition for optical films. The content of the solvent can be measured by subjecting the solvent to volatilization and drying with a pressure-sensitive adhesive composition for an optical film.

Further, the viscosity of the pressure-sensitive adhesive composition for an optical film of the present invention measured at 23 deg. C by a B-type viscometer (at a revolution of 20 rpm) is 200 mPa s or more and 5000 mPa s or less. When the viscosity is less than 200 mPa · s or more than 5000 mPa · s, durability and reworkability are difficult to be achieved at the same time, productivity during coating decreases, and the balance between the effect of suppressing the occurrence of warpage and sagging is reduced. The viscosity is preferably 400 mPa s or more and 4500 mPa s or less, more preferably 500 mPa s or more and 4000 mPa s or less, particularly preferably 500 mPa s or more and 3500 mPa s or less. Such a range of viscosity makes it possible to achieve both durability and reworkability, and in addition to a significant improvement in productivity at the time of coating, a balance between the effects of suppressing the occurrence of warping and pressing is particularly good.

Viscosity at 23 캜 of the pressure-sensitive adhesive composition for an optical film of the present invention measured by a B-type viscometer (number of revolutions: 20 rpm) can control viscosity of the (meth) acrylate copolymer (A) such as molecular weight, solid content, By the addition of an additive. In the present specification, the viscosity at 23 deg. C measured by a B-type viscometer (number of revolutions: 20 rpm) of the pressure-sensitive adhesive composition for an optical film can be measured by the method described in the examples.

≪ Silane coupling agent (E) >

The pressure-sensitive adhesive composition for an optical film of the present invention preferably further comprises a silane coupling agent (E). The silane coupling agent (E) can contribute mainly to improvement of durability in the pressure-sensitive adhesive composition for an optical film and improvement of adhesion with glass when the adherend is glass. In the present specification, the term "silane coupling agent" means a silane compound having a siloxane bond (Si-O-Si bond) and having two or more reactive groups in the molecule.

In the present invention, the silane coupling agent (E) is not particularly limited, but specific examples thereof include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane , Trimethylmethoxysilane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, n-butyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, Vinyltriethoxysilane, vinyltris (? Methoxyethoxy) silane,? - (? - methoxymethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropyltriethoxysilane,? -Methacryloxypropyltrimethoxysilane,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropyltrimethoxysilane, Acryloyloxypropylmethyldimethoxysilane,? -Methacryloyloxy Methacryloyloxypropyltriethoxysilane,? -Acryloyloxypropyltrimethoxysilane, N -? - (amino (meth) acrylate, methacryloxypropyltrimethoxysilane, (Aminoethyl) -? - aminopropyltrimethoxysilane, N -? - (aminoethyl) -? - aminopropyltrimethoxysilane, Aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ- An epoxy group (glycidoxy group), an amino group, an amino group, a hydroxyl group, an amino group, an amino group, a carboxyl group, A silane coupling agent having a functional group such as a mercapto group and a (meth) acryloyl group, A silane coupling agent containing a functional group having reactivity function groups, can also be used compounds having another coupling agent, a polyisocyanate such as a silyl group can be obtained by reacting a hydrolyzable in any ratio with respect to each functional group.

The silane coupling agent may be a compound or a commercially available product. Examples of commercially available silane coupling agents include KBM-303, KBM-403, KBE-402, KBE-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM- -846, KBE-9007 (manufactured by Shinetsu Kagaku Kogyo Co., Ltd.) and the like.

The silane coupling agent (E) may be used singly or in combination of two or more.

When the silane coupling agent (E) is contained in the pressure-sensitive adhesive composition for an optical film of the present invention, the content of the silane coupling agent (E) is not particularly limited, but is preferably 0.001 parts by mass or more based on 100 parts by mass of the copolymer (A) More preferably not less than 0.005 mass parts and not more than 5 mass parts, more preferably not less than 0.01 mass parts and not more than 3 mass parts, and particularly preferably not less than 0.01 mass parts and not more than 1 mass parts. When the content is 0.001 parts by mass or more, it is preferable from the viewpoint that the effect on durability can be exhibited even if it is placed in a harsh environment. On the other hand, when the content is 10 parts by mass or less, it is preferable from the viewpoint that the deterioration of the heating foaming originating from the low molecular weight compound disappears.

≪ Silicate oligomer (F) >

The pressure-sensitive adhesive composition for an optical film of the present invention preferably further comprises a silicate oligomer (F). The silicate oligomer (F) in the pressure-sensitive adhesive composition for an optical film can mainly contribute to the improvement of the lithography workability.

The silicate oligomer (F) affecting the present invention has a structure represented by the following formula (1).

≪ Formula (1) >

R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group, X ¹ and X ² each independently represent a hydrogen atom, a carbon number of 1 to 20 And n is an integer of 1 or more and 100 or less and preferably an integer of 2 or more and 100 or less. The alkyl group and the phenyl group which are related to each other may be substituted or unsubstituted. The alkyl group may have a straight chain structure or a branched chain structure.

Among the compounds represented by the above formula (1), it is preferable that methyl silicate oligomers in which R ¹ and R ² and both of X ¹ and X ² are methyl groups in view of easiness of both durability and reworkability in the present invention. On the other hand, the silicate oligomer (F) may be used singly or in combination of two or more.

In the present invention, the weight average molecular weight of the silicate oligomer (F) is not particularly limited, but is preferably 300 or more and 30000 or less, more preferably 500 or more and 25000 or less, still more preferably 600 or more and 5,000 or less, Preferably not less than 600 and not more than 5,000. When the weight-average molecular weight is 300 or more, it is preferable from the viewpoint of easily securing reworkability. On the other hand, when it is 30,000 or less, it is preferable from the viewpoint of ensuring durability. On the other hand, the weight average molecular weight of the silicate oligomer (F) can be measured by the same method as the method of measuring the weight average molecular weight of the copolymer (A) disclosed in the examples.

When the pressure-sensitive adhesive composition for an optical film of the present invention contains a silicate oligomer (F), the content of the silicate oligomer (F) is not particularly limited, but is preferably 0.01 part by mass to 50 parts by mass with respect to 100 parts by mass of the copolymer (A) Or less, more preferably 0.3 parts by mass or more and 10 parts by mass or less, and still more preferably 0.5 parts by mass or more and 5 parts by mass or less. When the content is 0.01 part by mass or more, it is preferable that the durability effect is exhibited even when it is placed in a harsh environment. On the other hand, when the content is 50 parts by mass or less, reworkability and durability are easily compatible.

≪ High softening point resin (G) >

The pressure-sensitive adhesive composition for an optical film of the present invention preferably further contains a high softening point resin (G) having a softening point of 60 ° C or more and 200 ° C or less (hereinafter, simply referred to as "high softening point resin (G)"). It is possible to provide a pressure-sensitive adhesive composition having the properties of being softened to a certain degree at room temperature and softened at a high temperature by adding the high softening point resin (G). By adding the high softening point resin (G) and having such properties, it is possible to make it hard at room temperature to effectively suppress the occurrence of pressing. Further, it is softened at a high temperature, and can be placed under a high temperature (for example, 85 DEG C) environment to have a stress relaxation property, so that occurrence of warpage can be suppressed effectively.

The high softening point resin (G) usable in the present invention is not particularly limited and may be a softening point not lower than 60 ° C and not higher than 200 ° C from the viewpoint of effectively exhibiting the above-mentioned action and effect, . Specific examples thereof include, for example, aliphatic petroleum resin, alicyclic hydrocarbon resin, aromatic petroleum resin, fully hydrogenated aliphatic petroleum resin, fully hydrogenated alicyclic hydrocarbon resin, fully hydrogenated aromatic petroleum resin, partially hydrogenated aliphatic petroleum resin, A partially hydrogenated alicyclic hydrocarbon resin, a partially hydrogenated aromatic petroleum resin, an aromatic hydrocarbon resin, an aliphatic saturated hydrocarbon resin, a terpene resin, a terpene phenol resin, a hydrogenated terpene resin, a coumarone-indene resin, rosin acid, (Rosin or rosin derivative) such as rosin ester resin and rosin ester resin (rosin acid ester), an epoxy resin, a phenol resin, an oil-soluble phenol (resin) . These high softening point resins (G) may be used singly or in combination of two or more kinds. Of these, alicyclic hydrocarbon resins, terpene phenol resins and terpene resins are more preferable from the viewpoint of good compatibility with the copolymer (A). The high softening point resin (G) is more preferably a rosin ester-based resin from the viewpoint that compatibility with other components of the pressure-sensitive adhesive composition is very good and transparency is easily obtained when applied to an optical film.

The high softening point resin (G) may be a compound or a commercially available product.

Examples of commercially available products of rosin ester based resins include Fine Crystal KR-85 (softening point 80-87 占 폚, hereinafter referred to as softening point), Fine Crystal KR-612 (80-90 100 ° C), Fine Crystal KR-614 (84-94 ° C), Fine Crystal KE-100 (95-105 ° C), Fine Crystal KE-311 , Fine Crystal KE-359 (94-104 ℃), Fine Crystal KE-604 (124-134 ℃), Fine Crystal KR-120 (110-130 ℃), Fine Crystal KR-140 (KR-614 (84-94 占 폚), Fine Crystal D-6011 (84-99 占 폚) and Fine Crystal KR-50M (145-160 占 폚) (manufactured by Aarakawachem KK) . They are very light color rosins and are best used for optical applications where transparency is required.

Other examples of commercially available rosin ester-based resins include Super Ester A-75 (70-80 ° C), Super Ester A-100 (95-105 ° C), Super Ester A-115 (108-120 ° C) -125 (120-130 占 폚) (manufactured by Arakawa Chemical Industries Co., Ltd.).

Examples of commercially available alicyclic hydrocarbon resins include Arcon P-90 (85-95 ° C), Arcon P-100 (95-105 ° C), Arcon (registered trademark) P-115 (95-150 占 폚), Arcon P-125 (120-130 占 폚), Arcon P-140 (135-145 占 폚), Arcon M- Arcon M-115 (110-120 占 폚), and Arcon M-135 (130-140 占 폚) (all manufactured by Arakawa Chemical Industries Co., Ltd.).

Examples of commercially available products of terpene phenol resins include TAMANOL 803L (145-160 占 폚), Tamanol 901 (125-135 占 폚) (manufactured by Arakawa Chemical Industries, Ltd.) (Registered trademark) U130 (125-135 占 폚), YS Poristar U115 (110-120 占 폚), YS Poristar T160 (155-165 占 폚), YS Poristar T145 (140-150 占 폚), YS YS Polystar T100 (125-135 占 폚), YS Polystar T115 (110-120 占 폚), YS Polystar T100 (95-105 占 폚), YS Polystar T80 (75-85 占 폚), YS Polystar S145 150 ° C), YS Poristar G150 (145-155 ° C), YS Poristar G125 (120-130 ° C), YS Poristar N125 (120-130 ° C), YS Poristar K125 (120-130 ° C) Star TH130 (125-135 占 폚) (manufactured by Yasuhara Chemical Co., Ltd.) and the like.

Examples of commercially available terpene resins include YS resin PX1250 (120-130 占 폚), YS resin PX1150 (110-120 占 폚), YS resin PX1000 (95-105 占 폚), YS resin PX800 YS resin TO105 (110-120 占 폚), YS resin TO105 (100-110 占 폚), YS resin TO85 (120-130 占 폚), YS resin TO105 (80-90 DEG C) (manufactured by Yasuhara Chemical Co., Ltd.) and the like.

When the high softening point resin (G) is added to the pressure-sensitive adhesive composition for an optical film of the present invention, the amount of the high softening point resin (G) to be added is not particularly limited, but is preferably 0.1 mass More preferably not less than 30 parts by mass, more preferably not less than 0.5 parts by mass nor more than 25 parts by mass, further preferably not less than 1 part by mass nor more than 20 parts by mass, particularly preferably not less than 2 parts by mass nor more than 15 parts by mass. When the content is at least 0.1 part by mass, it is preferable from the viewpoint that the effect of softening occurs in the durability test. It is also preferable from the viewpoint that the occurrence of warpage can be suppressed. On the other hand, when the content is 30 parts by mass or less, it is preferable from the viewpoint that the deterioration of durability due to a low molecular weight substance can be suppressed. From the viewpoint that durability can be ensured even in a harsh environment such that the flexibility of the pressure-sensitive adhesive composition can be effectively suppressed even in a low-temperature region such as -25 占 폚 or lower.

The softening point of the high softening point resin (G) is preferably not less than 60 DEG C and not more than 200 DEG C, but further preferably has a heat resistance retention, a tackiness, flexibility in a low temperature region such as -25 DEG C or less, improvement in durability and reworkability, More preferably 70 deg. C or more and 150 deg. C or less, further preferably 80 deg. C or more and 140 deg. C or less, particularly preferably 85 deg. C or more and 130 deg. In the present invention, the softening point is a value measured by the method described in JIS K6863 (1994).

≪ Other additive components >

The pressure-sensitive adhesive composition for an optical film of the present invention may contain, if necessary, known additives such as a crosslinking accelerator, an antioxidant, a filler, a colorant (such as a pigment or a dye), an ultraviolet absorbent, an antioxidant, a chain transfer agent, a plasticizer, a softener, a surfactant, The additive component (other additive component) may be contained within a range not to impair the effect of the present invention.

<Preparation (Preparation) of Pressure-Sensitive Adhesive Composition>

The pressure-sensitive adhesive composition for an optical film in the present invention is not particularly limited, and examples thereof include a copolymer (A), a peroxide (B), a crosslinking agent (C) and a solvent (D) other than peroxide, a silane coupling agent (E), silicate oligomer (F), and other additives. On the other hand, the order of mixing and the mixing temperature of each of the components may be adjusted, and it may be suitably adjusted by a person skilled in the art without particular limitation.

[Usage]

The above-described pressure-sensitive adhesive composition for an optical film of the present invention is suitable for various uses. For example, an optical member such as an optical film. In particular, it can be suitably used for a thin type adhesive optical film which is recently used for a large liquid crystal panel.

Examples of such an optical film include a polarizing plate, a retardation plate for preventing coloring, an optical compensation film such as a viewing angle enlarging film for improving the viewing angle of a liquid crystal monitor, a luminance improving film for enhancing contrast of the display, and those laminated thereon.

The form of the pressure-sensitive adhesive layer formed by the above-mentioned pressure-sensitive adhesive composition for optical film in the present invention, the form of the optical member in which the pressure-sensitive adhesive layer is formed on the optical film, the form in which the optical film is a polarizer, An organic EL display device, a flat panel display (PDP), a micro LED display, a curved display, or a flexible display. Each will be described below.

<Pressure-sensitive adhesive layer>

According to one aspect of the present invention, there is provided a pressure-sensitive adhesive layer for an optical film formed from the pressure-sensitive adhesive composition for an optical film of the present invention.

The pressure-sensitive adhesive layer of the present invention may have a warp of less than 1.5 mm and a pressing of less than 5 탆. In this range, both the warping and the pressing are low and can be used as a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer of the present invention can simultaneously suppress both bending and pressing. The above "warp" and "pressed" can be measured as described above in the following experimental examples.

The pressure-sensitive adhesive layer of the present invention may have an adhesive strength of 10 N / 25 mm or less after heat treatment at 50 캜 for 48 hours, for example, 7 N / 25 mm or less. In the above range, the recrystallization after heating may be good.

The thickness (thickness after drying) of the pressure-sensitive adhesive layer of the present invention can be suitably set by a person skilled in the art depending on the use thereof, but is preferably from 1 탆 to 200 탆, more preferably from 3 탆 to 75 탆, Is not less than 5 mu m and not more than 40 mu m, particularly preferably not less than 7 mu m and not more than 35 mu m, and most preferably not less than 10 mu m and not more than 30 mu m. When the thickness is within the above range, it is preferable from the viewpoint that a good balance of durability and adhesive property is obtained.

The gel fraction immediately after drying of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably 95% or less from the viewpoint of piercing or slitting. In addition, from the viewpoint of eliminating the problem of pressing and durability in the pressure-sensitive adhesive layer immediately after drying and not requiring an aging treatment, it is preferably 40% or more, more preferably 65% or more. The gel fraction can be controlled by controlling the amount of crosslinking agent or the amount of peroxide. On the other hand, the gel fraction immediately after drying of the pressure-sensitive adhesive layer adopts the value measured by the method described in the embodiment.

[Method of producing pressure-sensitive adhesive layer]

According to another aspect of the present invention, there is also provided a process for producing a pressure-sensitive adhesive layer for an optical film, which comprises coating a release film obtained by peeling the pressure-sensitive adhesive composition for an optical film of the present invention and then heat- do.

When the pressure-sensitive adhesive composition is used in an optical film, the pressure-sensitive adhesive layer may be formed by directly coating the pressure-sensitive adhesive composition on the optical film. Alternatively, the pressure-sensitive adhesive composition may be coated on the releasable film to form a pressure- . In addition, a film having releasability of the pressure-sensitive adhesive layer member thus produced can be rolled together in a manufacturing process to be rolled, and when it is cut or cut according to need and is adhered to various optical films or liquid crystal panels, The film having releasability can be used by being detached. Furthermore, the film having releasability can also play a role of protecting the pressure-sensitive adhesive layer until the pressure-sensitive adhesive layer is provided for actual use. In the present specification, a film having such releasability is also referred to as a releasing sheet (separator).

Examples of the constituent material of the release sheet include plastic films such as polyethylene, polypropylene, polyethylene terephthalate and polyester films, porous materials such as paper, cloth and nonwoven fabric, nets, foam sheets, metal foils, A thin laminate, and the like. However, from the viewpoint of excellent surface smoothness, the plastic film can be optimally adopted.

The thickness of the release sheet is usually from 5 탆 to 200 탆, and preferably from 5 탆 to 100 탆.

The release sheet can further be subjected to antistatic treatment such as releasing treatment with a silicone, fluorine, long chain alkyl or fatty acid amide releasing agent, silica powder, antifouling treatment, coating type, refining injection type, and vapor deposition type. In particular, from the viewpoint of increasing the releasability of the pressure-sensitive adhesive layer, it is preferable that the surface of the release sheet is subjected to a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment.

When the pressure-sensitive adhesive composition for an optical film of the present invention is coated on a release sheet obtained by the present invention in the present invention, various known methods may be used without particular limitation. For example, extrusion coating methods such as roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, And the like.

In the method for producing a pressure-sensitive adhesive layer of the present invention, the above-described pressure-sensitive adhesive composition for an optical film is coated on a release sheet and then subjected to a heat treatment. In the related heat treatment process, not only the solvent in the coating film obtained by coating is dried and removed, but also the purpose of crosslinking reaction of the above-mentioned pressure-sensitive adhesive composition for optical film. The temperature of the heat treatment is preferably not less than 40 ° C and not more than 150 ° C, more preferably not less than 50 ° C and not more than 130 ° C, and more preferably not less than 80 ° C and not more than 120 ° C. By setting the temperature of the heat treatment within the above range, a pressure-sensitive adhesive layer having excellent adhesive properties can be obtained.

The time for the heat treatment can be appropriately set, but is preferably 5 seconds or more and 20 minutes or less, more preferably 5 seconds or more and 10 minutes or less, further preferably 10 seconds or more and 5 minutes or less, Is not less than 10 seconds and not more than 2 minutes.

The means for the heat treatment is not particularly limited and various known methods can be used. For example, there are a paralell type drying system in which hot wind is blown in the vertical direction in the film transport direction, a counter drying system in which hot wind is blown in the transport direction of the film in the upper and lower direction, and a float- Method and the like.

 [Optical member]

According to one aspect of the present invention, there is provided an optical member having the above-described pressure-sensitive adhesive layer for an optical film and a first optical film formed on one side of the pressure-sensitive adhesive layer.

The optical member of the present invention may further have a glass or a second optical film on the surface of the pressure-sensitive adhesive layer of the present invention opposite to the surface on which the first optical film is formed. Here, the "first optical film" and the "second optical film" may be films having the same constitution (material, function, etc.), or may be films having different configurations (material, function, etc.). In the present invention, the first optical film (or the second optical film) is also provided as a polarizer plate.

In the present invention, the above-mentioned pressure-sensitive adhesive composition may be used to form a pressure-sensitive adhesive layer directly on one side or both sides of an optical film. However, for the reasons stated above, a pressure- It is preferable to use it by transferring. Further, the surface of the optical film may be subjected to a basic treatment such as the formation of the adhesion-treated layer or an antistatic layer depending on the material thereof before the transfer. The adhesive treatment may also be carried out on the surface of the pressure-sensitive adhesive layer. From the viewpoint of strongly bonding the optical film and the pressure-sensitive adhesive layer, it is preferable that the pressure-sensitive adhesive layer has the adhesive treatment layer between the optical film and the pressure-sensitive adhesive layer for an optical film of the present invention.

&Lt; Adhesion-Treated Layer (Adhesive Layer) >

It is preferable that the optical member of the present invention further has at least one adhesion-treated layer between the first optical film and the pressure-sensitive adhesive layer for the optical film.

In a more preferred embodiment, the optical member of the present invention further comprises a first adhesive treatment layer on the side of the first optical film opposite to the pressure-sensitive adhesive layer for optical film, and the pressure- A second adhesive treatment layer is formed on the side facing the first optical film. The structure having both the first and second adhesive treatment layers in the optical member is preferable from the viewpoint of bonding the optical film and the pressure sensitive adhesive layer more strongly.

As the adhesive treatment layer, a surface of a member contacting the pressure-sensitive adhesive layer such as a corona treatment or a plasma treatment may be treated, or a separate member such as a primer layer may be formed on the surface of the member in contact with the pressure-sensitive adhesive layer.

The material constituting the primer layer preferably has a good adhesion with a member in contact with the primer layer and forms a film with excellent cohesive strength. For example, various polymers, sols of metal oxides, silica sol, and the like can be used. Of these, polymers can be preferably used. The primer layer may have an antistatic function.

Examples of the polymers constituting the primer layer include oxazoline group-containing polymers, polyurethane resins, polyester resins, and polymers containing amino groups in the molecule.

Among them, a polyurethane resin and an oxazoline group-containing polymer may be more preferably used.

Commercially available oxazoline group-containing polymers may be used. For example, Epochuros (registered trademark) series of Nihon Shokubai Co., Ltd. (for example, Epochuos (registered trademark) WS700), but the present invention is not limited thereto. Further, those disclosed in paragraphs &quot; 0107 &quot; to &quot; 0113 &quot; of Japanese Patent Laid-Open Publication No. 2011-105918 can be suitably used for polyurethane resin, polyester resin and polymers containing amino groups in the molecule.

The thickness of the primer layer is preferably 10 nm or more and 5000 nm or less, and more preferably 50 nm or more and 500 nm or less. Within the above range, the optical properties can be maintained while exhibiting sufficient strength and adhesion.

The method of forming the primer layer is not particularly limited, and the primer layer can be formed by coating the material of the primer layer (lower coating agent) using a coating method such as a coating method, a dipping method, a spraying method, and the like.

&Lt; Optical film &

As the optical film (first optical film or second optical film) in the present invention, an optical compensation film such as a polarizing plate, a retardation plate for preventing coloring, a viewing angle enlarging film for improving the viewing angle of a liquid crystal monitor, For example, a brightness enhancement film for a liquid crystal display device, and those in which these are laminated.

<Polarizer>

The polarizing plate suitable as an optical film in the present invention can be produced by adhering a protective film and a polarizer to each other with an adhesive agent by a conventionally known method, and curing the film by heat drying or ultraviolet ray or electron beam. The applied adhesive forms an adhesive layer because it exhibits adhesiveness by curing in drying, ultraviolet rays, electron beams and the like.

The polarizer is not particularly limited, and conventionally known ones can be used. For example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene / vinyl acetate copolymerization system partially saponified film may be produced by adsorbing a dichroic material such as iodine or a dichroic dye, Dehydrated polyvinyl alcohol, dehydrochlorinated polyvinyl chloride, and the like, polyene-based oriented films, and the like.

Among them, polarizers prepared by staining a polyvinyl alcohol film having an average degree of polymerization of 2000 to 2800 and a degree of saponification of 90 to 100 mol% with iodine and monoaxially stretching to 3 to 8 times are particularly preferable. More specifically, such a polarizer can be obtained by, for example, dipping a polyvinyl alcohol film in an aqueous solution of iodine, and stretching it.

As a method of immersing in an aqueous solution of iodine, it is preferable to immerse in an aqueous solution containing iodine and / or potassium iodide in an amount of, for example, 0.1% by mass or more and 10% by mass or less. If necessary, it may be immersed in an aqueous solution of boric acid or potassium borate at 50 ° C or higher and 70 ° C or lower, or may be immersed in water at 25 ° C or higher and 35 ° C or lower for prevention of washing and uneven dyeing. The stretching may be performed after dyeing with iodine, the stretching while dyeing, or the stretching may be followed by dyeing with iodine. After dyeing and stretching, it may be washed with water and dried at 35 ° C or more and 55 ° C or less for 1 minute or more and 10 minutes or less. These polarizers are available in a variety of different forms.

The thickness of the polarizer is not particularly limited, but is generally 3 m or more and 80 m or less.

In view of the fact that higher durability is required as an optical film in the present invention, a polarizing plate having one side or both sides protected is preferable as the optical film. As a method of protection, a known method such as bonding the protective films to each other may be appropriately used without being particularly limited.

As the protective film, a material excellent in transparency, mechanical strength, heat stability, moisture barrier property, isotropy and the like is preferable. Examples of the resin include acrylic resins, cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, (Meth) acrylic resins such as polymethylmethacrylate, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, epoxy resins, and mixtures thereof .

On the other hand, a transparent protective film is bonded to one side of the polarizer by an adhesive, and a transparent protective film or a protective layer is formed by bonding a thermosetting resin such as a (meth) acrylic type, a urethane type, an acrylic urethane type, an epoxy type, Can be used.

The thickness of the polarizing plate is not particularly limited, but is generally 20 占 퐉 or more and 200 占 퐉 or less. From the viewpoint of thinning, the thickness of the polarizing plate is preferably 100 占 퐉 or less, more preferably 75 占 퐉 or less, and particularly preferably 50 占 퐉 or less. Such a thin polarizing plate is preferable from the standpoint that the effect of the pressure-sensitive adhesive composition of the present invention is more conspicuously expressed.

The method of producing the polarizing plate is not particularly limited and, for example, after coating the adhesive, the polarizing plate and the protective film can be bonded to each other by a roll laminate or the like. They may be suitably dried or subjected to a curing process such as ultraviolet rays or electron beams. When applying an adhesive, either a protective film or a polarizer may be coated or both coatings may be applied. The adhesive is preferably applied so that the thickness of the adhesive layer after drying is 10 nm or more and 10 m or less. The adhesive is not particularly limited and may be suitably used in accordance with the material of the polarizer. For example, when a polyvinyl alcohol-based film is used as the polarizer, an acrylic, epoxy, or acrylic-epoxy system may be used as a polyvinyl alcohol-based adhesive or an ultraviolet-curable adhesive. The thickness of the adhesive layer is preferably not less than 10 nm and not more than 200 nm in the case of the polyvinyl alcohol adhesive agent and not less than 0.2 μm and not more than 10 μm in the ultraviolet curing adhesive agent, since a uniform in-plane thickness and a sufficient adhesive force are obtained.

An adhesive type polarizing plate in which a pressure-sensitive adhesive layer is formed in the present invention can also be provided. On the other hand, the construction and manufacturing of the adhesive polarizing plate are the same as those of the optical film having the above-mentioned pressure-sensitive adhesive layer, and the description thereof is omitted here.

 [Image display device]

The present invention also provides an image display apparatus using at least one of the optical members described above.

The image display device is not particularly limited, and examples thereof include a liquid crystal display device, an organic EL display device, a flat panel display (PDP), a micro LED display, and the like. In addition, from the viewpoint that the effect of the pressure-sensitive adhesive composition of the present invention is more remarkably expressed, a particularly thin image display apparatus is preferably applied.

Example

The present invention will be described in more detail with reference to the following examples and comparative examples, but the technical scope of the present invention is not limited to the following examples.

Unless otherwise noted in the following operations, the measurement of the operation and physical properties is performed under conditions of 23 deg. C and a relative humidity of 55% RH.

(Measurement of Weight Average Molecular Weight (Mw) of Copolymer (A)) [

The weight average molecular weights of the respective (meth) acrylate copolymers (A) prepared in the following Production Examples were measured by gel permeation chromatography (GPC) (measurement conditions are as follows).

Analytical Apparatus: HLC-8120GPC manufactured by Tosoh Corporation

Column: manufactured by Toso Co., Ltd. G7000HXL + GMHXL + GMHXL

· Column size: Each 7.8mmφ × 30cm 90cm in total

· Column temperature: 40 ° C

· Flow rate: 0.8 ml / min

Injection amount: 100 μl

Eluent: tetrahydrofuran

Detector: Differential refractometer (RI)

Standard sample: polystyrene.

 (Measurement of weight average molecular weight (Mw) of silicate oligomer (F)) [

The weight average molecular weight of the silicate oligomer (F) used in the following examples was measured by gel permeation chromatography (GPC) (measurement conditions are as follows):

Analytical Apparatus: Toso Co., Ltd., HLC-8120GPC

Column: TSKgel SuperHZM-H / HZ4000 / HZ2000

· Column size: 6.0 mm ID × 150 mm

· Column temperature: 40 ° C

· Flow rate: 0.6 ml / min

· Injection amount: 20 μl

Eluent: tetrahydrofuran

Detector: Differential refractometer (RI)

Standard sample: polystyrene.

Production Example 1: Preparation of a solution of (meth) acrylate copolymer (A1)

To a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas introducing tube and a condenser, 99 parts by mass of n-butyl acrylate (Nippon Shokubai Co., Ltd.), 4 parts by mass of 4-hydroxybutyl acrylate (OSAKA ORGANIC And 0.1 part by mass of 2,2'-azobisisobutyronitrile (Wako Pure Chemical Industries, Ltd.) as a polymerization initiator were added to 100 parts by mass of ethyl acetate, And nitrogen gas was introduced with gentle stirring. The temperature of the liquid in the flask was elevated to reflux the ethyl acetate and the polymerization reaction was carried out for 5 hours to obtain a solution of the (meth) acrylate copolymer (A1) having a weight average molecular weight (Mw) of 90,000 did.

Production Examples 2 to 9: Preparation of Solutions of (Meth) Acrylate Copolymers (A2) to (A9)

(Meth) acrylate copolymer was changed as shown in Table 1 below, and the amount of the polymerization initiator and the reaction time were appropriately changed, the same operations as in Production Example 1 were carried out To prepare solutions of (meth) acrylate copolymers (A2) to (A9). The weight average molecular weights (Mw) of the (meth) acrylate copolymers (A1) to (A9) are also shown in Table 1. Meanwhile, the blank in Table 1 means that the corresponding monomer is not used.

Copolymer Monomer composition (parts by mass) Mw BA BzA MA 4HBA AA MMA Production Example 1 A1 99 - - One - - 90 million Production Example 2 A2 97 - - One 2 - 90 million Production Example 3 A3 70 13 16 One - - 40 million Production Example 4 A4 70 13 16 One - - 70 million Production Example 5 A5 70 13 16 One - - 90 million Production Example 6 A6 70 13 16 One - - 105 million Production Example 7 A7 70 13 16 One - - 25 million Production Example 8 A8 70 13 16 One - - 1.5 million Production Example 9 A9 60 13 16 One - 10 90 million

Note) BA: n-butyl acrylate (Nihon Shokuba Co., Ltd., Tg of homopolymer: -45 ° C)

BzA: Benzyl acrylate (Hitach Chemical Co., Ltd., Tg of homopolymer: -9 캜)

MA: methyl methacrylate (Nihon Shokuba Co., Ltd., Tg of homopolymer: 8 占 폚)

4HBA: 4-hydroxybutyl acrylate (Osaka Organic Chemical Industry Co., Ltd., Tg of homopolymer: -32 ° C)

AA: Acrylic acid (Nihon Shokuba Co., Ltd., Tg of homopolymer: 106 ° C)

MMA: methyl methacrylate (Tg of homopolymer: Mitsubishi Gas Chemical Co., Ltd., 105 DEG C)

&Lt; Example 1 >

[Preparation of pressure-sensitive adhesive composition for optical film]

(Per 100 parts by mass of the solid content of the (meth) acrylate copolymer (A1) solution obtained in Preparation Example 1 (100 parts by mass of the (meth) acrylate copolymer (A1) , 2 parts by mass of peroyl L (manufactured by Iyu KK), 0.5 part by mass of a trimethylol propane adduct of xylene diisocyanate (manufactured by Nippon Kayaku Co., Ltd.) as a cross-linking agent (C) KBM-403 (3-glycidoxypropyl tri (meth) acrylate) as a silane coupling agent (E), 0.1 part by mass (in terms of active ingredient) Methoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with stirring to prepare a pressure-sensitive adhesive composition for an optical film (solid content: 25 mass%).

[Formation of pressure-sensitive adhesive layer]

The pressure-sensitive adhesive composition for an optical film obtained above was applied on one side of a silicone-treated polyethylene terephthalate (PET) film (MRF38, manufactured by Mitsubishi Chemical Co., Ltd., without oligomer-preventing layer) having a thickness of 38 탆 to form a pressure- , And was subjected to a heat treatment at 110 DEG C for 2 minutes to form the pressure-sensitive adhesive layer of Example 1. On the other hand, the heating treatment was performed by a float drying method in which hot air was directly blown from above and below the film.

[Production of optical member]

(Preparation of double-side protective polarizing plate)

A double-side protective polarizing plate was produced as an optical film by the following steps.

A polyvinyl alcohol film having a thickness of 60 占 퐉 was stretched to 3 times while dyeing in an iodine solution at a concentration of 0.3 mass% at 30 占 폚 for one minute between rolls having different speed ratios. Thereafter, the film stretched to 3 times was stretched until the total stretching magnification was 6 times while immersing the film in an aqueous solution containing 60% by mass of boric acid and 10% by mass concentration of potassium iodide at 60 占 폚 for 0.5 minutes. Then, the film stretched to 6 times was washed by immersing in an aqueous solution containing potassium borate at a concentration of 1.5% by mass at 30 캜 for 10 seconds, and then dried at 50 캜 for 4 minutes to obtain a polarizer. A triacetyl cellulose (TAC) film (protective film) having a thickness of 40 占 퐉 was coated on one side of the polarizer and a PET film (COSMO SHINE (registered trademark) super birefringence (trade name) manufactured by Toyobo Co., (SRF) PET film (protective film)) was bonded with a polyvinyl alcohol-based adhesive to prepare a thin polarizing plate having a total thickness of 143 μm (also referred to as a double-side protective polarizing plate).

 (Production of a double-side protective polarizing plate having a pressure-sensitive adhesive layer)

The corona treatment was performed on the TAC film side of the double-side protective polarizing plate obtained above with a discharge amount of 80 [W · min / m ² ] to form the adhesive treatment layer. Then, a PET film (having been subjected to silicone treatment) having a pressure-sensitive adhesive layer formed thereon so as to be in contact with the formed adhesion-treated layer was transferred to prepare a double-side protective polarizer plate having the optical member of Example 1, that is, a pressure-sensitive adhesive layer.

&Lt; Examples 2 to 24 and Comparative Examples 1 to 5 >

(A), peroxide (B), a cross-linking agent (C) other than peroxide and, if necessary, a silane coupling agent (E) and a silicate coupling agent (E) constituting the pressure- Except that the type and amount (amount of addition) of the oligomer (F) and the heat treatment temperature at the time of forming the pressure-sensitive adhesive layer were changed, the procedure of Example 1 was repeated, A double-side protective polarizing plate having a pressure-sensitive adhesive layer was produced.

Copolymer
(A) Peroxide (B) Cross-linking agent other than peroxide
(C) Silane coupling agent (E) Silicate oligomer
(F) Heating temperature (占 폚) / hour (minute) Kinds Kinds Addition amount
(Parts by mass) Kinds Addition amount
(Parts by mass) Kinds Addition amount
(Parts by mass) Kinds Addition amount
(Parts by mass) Mw Example 1 A1 Perl Linux with TCP / Perl 0.5 / 2 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 2 A2 Perl Linux with TCP / Perl 0.5 / 2 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 3 A3 Perl Linux with TCP / Perl 0.5 / 2 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 4 A4 Perl Linux with TCP / Perl 0.5 / 2 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 5 A5 Perroil TCP 2.5 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 6 A5 Perroil TCP 5 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 7 A5 Perroil TCP 9 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 8 A5 Perl Linux with TCP / Perl 0.5 / 2 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 9 A5 Peroil IPP 2.5 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 10 A5 Per butyl ND 2.5 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 11 A5 PERROY PV 2.5 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 12 A5 Paokuta O 2.5 D-110N 0.1 KBM-403 0.1 - - - 110/2 Example 13 A5 NIPA-BMT-K40 2.5 D-110N 0.1 KBM-403 0.1 - - - 140/2 Example 14 A6 Perl Linux with TCP / Perl 0.5 / 2 D-110N 0.1 KBM-403 0.1 - - - 110/2

Copolymer
(A) Peroxide (B) The crosslinking agent (C) other than the peroxide Silane coupling agent
(E) Kinds Kinds Addition amount
(Parts by mass) Kinds Addition amount
(Parts by mass) Kinds Addition amount
(Parts by mass) Example 15 A5 Perroil TCP 0.5 D-110N 0.1 - - Example 16 A5 Perroil TCP 0.5 D-110N 0.1 KBM-403 0.1 Example 17 A2 Perroil TCP 0.5 V-05 0.1 KBM-403 0.1 Example 18 A2 Perroil TCP 0.5 WS-500 0.1 KBM-403 0.1 Example 19 A2 Perroil TCP 0.5 TETRAD-X 0.1 KBM-403 0.1 Example 20 A2 Perroil TCP 0.5 PZ-33 0.1 KBM-403 0.1 Example 21 A5 Perroil TCP 0.5 D-110N 0.1 KBM-403 0.1 Example 22 A5 Perroil TCP 0.5 D-110N 0.1 KBM-403 0.1 Example 23 A9 Perroil TCP 0.5 D-110N 0.1 KBM-403 0.1 Example 24 A5 Perroil TCP 0.5 D-110N 0.1 KBM-403 0.1 Comparative Example 1 A5 - - D110-N 0.1 KBM-403 0.1 Comparative Example 2 A7 Perroil TCP 0.5 D110-N 0.1 KBM-403 0.1 Comparative Example 3 A8 Perroil TCP 0.5 D110-N 0.1 KBM-403 0.1 Comparative Example 4 A1 NIPA-BMT-K40 0.3 D110-N 0.1 KBM-403 0.1 Comparative Example 5 A5 NIPA-BMT-K40 0.3 D110-N 0.1 KBM-403 0.1

Silicate oligomer
(F) High softening point resin (G) (Meth) acrylic copolymer (H) Heating temperature (占 폚) /
Time (minutes) Kinds Addition amount
(Parts by mass) Mw Kinds Addition amount
(Parts by mass) Kinds Addition amount
(Parts by mass) Example 15 Silicate 53A 5 900 - - - - 110/2 Example 16 Silicate 53A 5 900 - - - - 110/2 Example 17 - - - - - - - 110/2 Example 18 - - - - - - - 110/2 Example 19 - - - - - - - 110/2 Example 20 - - - - - - - 110/2 Example 21 - - - Fine Crystal KE-100 5 - - 110/2 Example 22 - - - Fine Crystal KE-100 20 - - 110/2 Example 23 - - - - - - - 110/2 Example 24 - - - - - Alphon UH-2170 5 110/2 Comparative Example 1 - - - - - - - 110/2 Comparative Example 2 - - - - - - - 110/2 Comparative Example 3 - - - - - - - 110/2 Comparative Example 4 - - - - - - - 160/2 Comparative Example 5 - - - - - - - 180/2

In Tables 2 to 4,

1. When the blending amount (parts by mass) of the components (B), (C), (E), (F), (G) and (H) is 100 parts by mass (meth) . &Lt; / RTI &gt;

2. "-" in the table means that the relevant components are not blended

3. "Peroil TCP": a product (di (4-t-butylcyclohexyl) peroxydicarbonate, one minute half-life temperature: 92.1 ° C.)

4. "Peroil L": product of Iyu Corporation (dilauryl peroxide, one-minute half-life temperature: 116.4 ° C)

5. "Peroil IPP": a product made by Iyu Corporation (diisopropyl peroxydicarbonate, 1 minute half-life temperature: 88.3 ° C.)

6. "Perbutyl ND": a product of Iyu Corporation (t-butyl peroxyneodecanoate, 1-minute half-life temperature: 103.5 ° C.)

7. "Perbutyl PV" is a product (t-butyl peroxypivalate, one minute half life temperature: 110.3 ° C.) manufactured by Iyu Corporation

8. "Paokuta O" is a product (1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, one minute half life temperature: 124.3 ° C) manufactured by Iyu Corporation

9. "Naipa BMT-K40" is a product (benzoyl peroxide, effective content: 40% by mass, half-life temperature for one minute: 131.1 ° C) The addition amount of Table 2 is an addition amount in terms of the effective ingredient amount

10. "Methyl silicate 53A": a product (trade name: methyl silicate 53A) manufactured by COLCOAT CO., LTD.

11. "V-05": a carbodiimide crosslinking agent, product of Nisshinbo Chemical Co. (Carbodite (registered trademark) V-05)

12. &quot; WS-500 &quot;: an oxazoline crosslinking agent, product of Nihon Shokubai Co., Ltd. (Eposukuros (registered trademark) WS-500)

13. "TETRAD-X": an epoxy cross-linking agent, a product of Mitsubishi Gas Chemical Company (TETRAD (registered trademark) -X, N, N, N ', N'-tetraglycidyl-m- )to be

14. &quot; PZ-33 &quot;: aziridine crosslinking agent, manufactured by Nippon Shokubai Co., Ltd. (KEMITATE (registered trademark) PZ-33, 2,2-bishydroxymethylbutanol-tris [3- &Lt; / RTI &gt; ridinyl) propionate)

15. "Fine Crystal KE-100": a product of Arakawa Chemical Industries, Ltd. (softening point: 95-105 ° C (ring method), super pale rosin derivative)

16. "ALPHON (registered trademark) UH-2170": a product (a styrene-acrylic polymer without a solvent, weight average molecular weight (Mw) 14,000, glass transition temperature (Tg) 60 ° C.)

 [evaluation]

The following evaluations were performed on the pressure-sensitive adhesive composition for an optical film prepared in Examples 1 to 24 and Comparative Examples 1 to 5 and the double-side protective polarizer plate (sample) having a pressure-sensitive adhesive layer as an optical member.

&Lt; Coating liquid solid content (solid content) >

The pressure-sensitive adhesive composition for optical films prepared in Examples 1 to 24 and Comparative Examples 1 to 5 was heated and dried at 150 占 폚 for 30 minutes, and the remaining portion after volatilization was referred to as &quot; coating solution solid content did.

<Viscosity>

The pressure-sensitive adhesive composition for optical films prepared in Examples 1 to 24 and Comparative Examples 1 to 5 was rotated in a Brookfield viscometer (B-type viscometer) at a rotational speed of 20 rpm to measure the viscosity I read the numerical value and called the viscosity value.

<Warpage>

The optical member (double-sided protective polarizing plate with a pressure-sensitive adhesive layer) prepared in Examples 1 to 24 and Comparative Examples 1 to 5 was cut into a size of 100 mm in length x 50 mm in width and was called a sample. This sample was adhered to a non-alkali glass (EAGLEXG, made by Corning) having a length of 75 mm, a width of 150 mm and a width of 0.5 mm using a laminator. Then, the sample was autoclaved at 50 DEG C and 0.5 MPa for 15 minutes to completely adhere the sample to the non-acrylic glass. The sample subjected to such treatment was further subjected to a heat treatment at 85 캜 for 100 hours and then allowed to stand under the conditions of 25 캜 and 55% RH for 1 hour. Then, the surface having the convexity of the convexity was placed on the horizontal surface And the distance (mm) of the longest point from the horizontal plane among the four corners was measured. The evaluation criteria are as follows:

-Evaluation standard-

?: Deflection amount 0 mm or more and less than 0.5 mm

0: Deflection amount 0.5mm or more and less than 1.0mm

?: Deflection amount 1.0 mm or more and less than 1.5 mm

X: Deflection 1.5 mm or more.

<Compression>

The optical member (double-sided protective polarizing plate with a pressure-sensitive adhesive layer) immediately after coating (immediately after transferring the PET film having the pressure-sensitive adhesive layer formed thereon and within 10 minutes after the transfer) prepared in Examples 1 to 24 and Comparative Examples 1 to 5, Cut into a size of 100 mm x 100 mm, and a total of 300 pieces of sample pieces (samples) were produced. These sample pieces were piled up on the PET film (protective film) side of the polarizing plate (the side of the protective film on the side where the pressure-sensitive adhesive layer was not formed), piled up, loaded with a load of 1 kg, And the depth of the occurrence of the pressing was evaluated by a laser microscope (VK-X120) manufactured by Kogei Co., Ltd. The evaluation criteria are as follows:

-Evaluation standard-

?: Depth of pressing 0 占 퐉 or more and less than 1 占 퐉

0: depth of pressing 1 탆 or more and less than 3 탆

DELTA: Depth of pressing 3 占 퐉 or more and less than 5 占 퐉

X: Depth of pressing 5 占 퐉 or more.

<Durability>

A sample obtained by cutting the optical member (double-sided protective polarizing plate with a pressure-sensitive adhesive layer) manufactured in Examples 1 to 24 and Comparative Examples 1 to 5 to a size of 37 inches was immersed in a non-alkali glass (EAGLEXG, It was adhered using a laminator. Then, autoclave treatment was carried out at 50 DEG C and 0.5 MPa for 15 minutes, and the sample was brought into close contact with the completely non-acrylic glass. Samples subjected to such treatment were each provided in the following durability tests (1) to (3), and the appearance between the polarizing plate and the glass after each test was evaluated in the following manner on the basis of the following criteria:

(1) Treatment was carried out at 85 DEG C for 500 hours (heating test)

(2) Treatment was conducted for 500 hours in an atmosphere of 60 DEG C / relative humidity of 95% RH (humidification test)

(3) A total of 300 cycles (300 hours) were allowed to stand for 30 minutes in an environment at 85 캜 and then to stand for 30 minutes in an environment of -40 캜 for one cycle (one hour) (heat shock , HS) test.

Mock assessment

⊚: No change in appearance such as no foaming, peeling, peeling, etc.

0: There is little peeling or foaming at the end, and there is no practical problem

[Delta]: There is peeling or foaming at the end, but there is no practical problem if it is not for special use

X: Significant peeling at the end, causing a practical problem

<Gel fraction>

Based on the heat treatment temperature and time described in Tables 2 to 4, the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition prepared in Examples 1 to 24 and Comparative Examples 1 to 5 was applied to a release-treated polyethylene terephthalate (PET) film A sample having a configuration sandwiched from both sides was prepared, and this was called a sample for measuring the gel fraction.

Each sample was weighed immediately after the heat treatment and was called the initial weight (W1). Then, each sample was immersed in an ethyl acetate solution and allowed to stand for 1 week under an environment of 23 ° C and 55% RH. Thereafter, the insoluble matter was taken out, ethyl acetate was removed, and the sample was dried and the weight (W2) was measured. From the weight thus obtained, the gel fraction of each sample was calculated by the following formula (1).

&Lt; Formula 1 >

Gel fraction (%) = (W2 / W1) x 100

<Aging treatment>

When the gel fraction of the pressure-sensitive adhesive layer immediately after drying is equal to or larger than a certain region, there is no fear of pressing or durability, and no aging treatment is required (this is referred to as "agingless").

Therefore, based on the gel fraction of each sample measured by the above-mentioned method, the following criteria were determined, and the necessity of the aging treatment of each sample was evaluated:

Evaluation standard

0: Gel fraction 65% or more, no impact on press, processability, durability; No aging treatment required

?: Gel fraction of not less than 40% and not more than 65%; No aging treatment required

X: Less than 40% of the gel fraction, there is a concern that the pressing, the workability and the durability are deteriorated; Requires aging treatment.

<Oligomer contamination>

The pressure-sensitive adhesive compositions of Examples 1 to 24 and Comparative Examples 1 to 5 were coated on a polyethylene terephthalate (PET) film (38 占 퐉 thick, MRF38, manufactured by Mitsubishi Chemical Co., Ltd.) The coating was applied to the coating line for 2 hours under the indicated heat treatment temperature. Whether or not the PET oligomer was precipitated on the guide roll of the coating line when the heat treatment was carried out while carrying the film was observed in the eyes and evaluated according to the following criteria:

Evaluation standard

○: No PET oligomer precipitation on the guide roll.

Δ: There is little PET oligomer precipitation on the guide roll

X: There is a large amount of PET oligomer precipitation on the guide roll.

<Light Sources>

Each of the optical members prepared in Examples 1 to 24 and Comparative Examples 1 to 5 was cut into a size of 420 mm in length and 320 mm in width so that the upper and lower polarizers directly intersect each other to form a sample. This sample was pasted on both sides of a 0.7 mm thick non-alkali glass plate (Corning, EAGLEXG (registered trademark)) by a laminator so that it became Cross Nicol. Then, autoclave treatment was carried out at 50 캜 and 5 atm for 15 minutes to obtain a secondary sample (initial value). Thereafter, the secondary sample was treated for 48 hours at 105 ° C (after heating). The secondary sample after heating was placed on the backlight of 10,000 candela and the light leakage was evaluated by the following criteria by the following criteria:

Evaluation standard

&Amp; cir &amp;: No corners occurred and there is no practical problem.

?: A small amount of corner distortion occurred, but the display area does not show any problem.

DELTA: Corner unevenness occurred and a little appears in the display area, but there is no practical problem.

X: Corner unevenness occurs and appears in the display area severely, and there is a practical problem.

<Workability>

The optical member prepared in Examples 1 to 24 and Comparative Examples 1 to 5 was cut into a sample 1 having a width of 25 mm and a length of 100 mm and a sample 2 having a length of 420 mm and a width of 320 mm. The samples 1 and 2 were each stuck to a non-alkali glass plate (EAGLEXG, manufactured by Corning) having a thickness of 0.7 mm using a laminator, followed by autoclave treatment at 50 캜 and 5 atm for 15 minutes to complete adhesion. Thereafter, heat treatment was performed for 48 hours under drying conditions at 50 캜 (after heating).

The adhesive strength of the sample 1 was measured. The adhesive strength was measured in accordance with JIS Z0237 (2009) at a peel angle of 180 ° and a peel rate of 300 mm / min under conditions of 23 ° C and relative humidity of 50% RH in a tensile tester (Tensilon Universal Material Testing Machine, STA-1150 manufactured by Orientech Co., ), And the adhesive strength (N / 25 mm) when the sample 1 was removed was measured in accordance with the test method of the adhesive tape and the pressure-sensitive adhesive sheet.

In addition, the sample 2 (3 pieces) was peeled off from the sample with an alkali-free glass plate by a person's hand, and the reworkability was evaluated based on the following criteria (actual reworkability):

Evaluation standard

◎: Good peeling is possible without peeling of adhesive residue or film even on 3 sheets

&Amp; cir &amp;: Some of the three films were peeled off by re-peeling although the film was broken.

?: The film was broken even in three sheets, but peeling was possible by re-peeling.

X: Film residue was peeled off even after peeling the adhesive residue on three sheets or peeling it several times.

The evaluation results are shown in Table 5 below.

Coating solution
Solid content (%) Viscosity
(mPa.s) warp pressed durability 85 ° C 500 hr 60 ° C 95% RH
500 hr Thermal shock
300 cycles Example 1 25 1000 ○ ○ ◎ ◎ ◎ Example 2 25 1900 △ ◎ ◎ ◎ ◎ Example 3 35 2000 ◎ △ △ ◎ △ Example 4 30 2200 ○ ○ ○ ◎ ○ Example 5 25 2000 ○ ◎ ◎ ◎ ◎ Example 6 25 2000 ○ ○ ◎ ◎ ◎ Example 7 25 2000 ○ ○ ○ ○ ○ Example 8 25 1900 ○ ◎ ◎ ◎ ◎ Example 9 25 2000 ○ ◎ ◎ ◎ ◎ Example 10 25 2000 ○ ○ ○ ◎ ◎ Example 11 25 2000 ○ ○ △ ◎ ○ Example 12 25 2000 ○ ○ △ ◎ ○ Example 13 25 2000 ◎ △ △ ◎ △ Example 14 20 4500 ◎ ○ ◎ ◎ ◎ Example 15 25 2000 ○ ○ ◎ ◎ ◎ Example 16 25 2000 ○ ○ ◎ ◎ ◎ Example 17 25 1900 △ ◎ ◎ ◎ ◎ Example 18 25 1900 △ ◎ ◎ ◎ ◎ Example 19 25 1900 △ ◎ ◎ ◎ ◎ Example 20 25 1900 △ ◎ ◎ ◎ ◎

Coating solution
Solid content (%) Viscosity
(mPa.s) warp pressed durability 85 ° C 500 hr 60 ° C 95% RH
500 hr Thermal shock
300 cycles Example 21 25 1800 ○ ◎ ◎ ◎ ◎ Example 22 25 1700 ◎ ◎ ◎ ◎ ◎ Example 23 25 1900 △ ◎ ◎ ◎ ◎ Example 24 25 1900 △ ◎ ◎ ◎ ◎ Comparative Example 1 25 1900 ◎ x x ◎ x Comparative Example 2 25 150 ◎ x x ◎ △ Comparative Example 3 12 9500 x ◎ ◎ ◎ ◎ Comparative Example 4 25 2000 x ◎ ○ ◎ ○ Comparative Example 5 25 2000 x ◎ ○ ◎ ○

Gel fraction
(%) Aging
Lesbian Oligomer contamination Light leakage Re-workability Early
adhesiveness
(N / 25 mm) Initial Actual Workability Adhesion after heating
(N / 25 mm) Actual reworkability after heating Example 1 65 ○ ○ △ 2.2 ◎ 4.5 ◎ Example 2 72 ○ ○ △ 4.3 ◎ 9.5 △ Example 3 62 ○ ○ ○ 3.8 ◎ 6.2 ○ Example 4 66 ○ ○ ○ 3.2 ◎ 5.5 ○ Example 5 66 ○ ○ ○ 1.8 ◎ 3.2 ◎ Example 6 68 ○ ○ ○ 1.5 ◎ 3.0 ◎ Example 7 70 ○ ○ ○ 2.6 ◎ 5.2 ○ Example 8 67 ○ ○ ○ 2.5 ◎ 4.5 ◎ Example 9 70 ○ ○ ○ 2.3 ◎ 4.2 ◎ Example 10 65 ○ ○ ○ 2.8 ◎ 6.6 ○ Example 11 63 △ ○ ○ 3.8 ◎ 7.2 △ Example 12 61 △ ○ ○ 3.4 ◎ 8.3 △ Example 13 30 △ △ ○ 5.4 ○ 9.8 △ Example 14 71 ○ ○ ○ 2.5 ◎ 4.6 ◎ Example 15 65 ○ ○ ○ 1.8 ◎ 3.5 ◎ Example 16 67 ○ ○ ○ 2.0 ◎ 4.2 ◎ Example 17 67 ○ ○ ○ 4.5 ○ 9.4 △ Example 18 66 ○ ○ ○ 4.2 ○ 9.6 △ Example 19 65 ○ ○ ○ 4.8 ○ 9.4 △ Example 20 69 ○ ○ ○ 4.2 ○ 9.8 △

Gel fraction
(%) Aging
Lesbian Oligomer contamination Light leakage Re-workability Early
adhesiveness
(N / 25 mm) Initial Actual Workability Adhesion after heating
(N / 25 mm) Actual reworkability after heating Example 21 62 ○ ○ ○ 4.3 ◎ 6.5 ○ Example 22 60 ○ ○ ○ 4.5 ◎ 6.9 ○ Example 23 66 ○ ○ ○ 3.8 ◎ 6.5 ○ Example 24 63 ○ ○ ○ 4.2 ◎ 6.8 ○ Comparative Example 1 0.2 x ○ ○ 5.6 ○ 12.5 x Comparative Example 2 66 ○ ○ ○ 4.5 ◎ 11.8 x Comparative Example 3 75 ○ ○ ○ 2.2 ◎ 5.9 △ Comparative Example 4 65 ○ x ○ 3.5 ◎ 6.6 △ Comparative Example 5 66 ○ x ○ 3.8 ◎ 7.2 △

As clearly shown in Tables 5 to 8, the double-side protective polarizing plates having the pressure-sensitive adhesive layer using the pressure-sensitive adhesive composition for optical films of the present invention of Examples 1 to 24 were all excellent in harsh environments (high temperature, high humidity, It is possible to achieve both durability and reworkability of the substrate, and it is possible to suppress the occurrence of both warping and pressing. Specifically, the double-side protective polarizing plates (Examples 1 to 24) having the pressure-sensitive adhesive layer as the optical member having the pressure-sensitive adhesive layer obtainable with the pressure-sensitive adhesive composition for an optical film of the present invention exhibited peeling due to the pressure- No, there was almost no foaming. Further, the double-side protective polarizing plate having a pressure-sensitive adhesive layer as an optical member can be reduced in adhesion force immediately after being adhered to a conventionally thinned image display apparatus, for example, a liquid crystal cell of a large liquid crystal display apparatus, It is suggested that a double-side protective polarizing plate having a pressure-sensitive adhesive layer as an optical member can be easily peeled from a liquid crystal cell or the like without increasing the adhesion to a liquid crystal cell or the like even after a long period of time has elapsed or it is stored at a high temperature. As a result, it was confirmed that the reworkability is excellent, the liquid crystal cell is damaged, contaminated, and can be reused. Further, in a liquid crystal cell or the like which can be used in a conventional large-sized image display apparatus, it is difficult to suppress both the warping of the liquid crystal cell and the pressing of the pressure-sensitive adhesive layer. However, according to Examples 1 to 24, I could confirm. On the other hand, the double-side protective polarizing plates having the pressure-sensitive adhesive layers of Comparative Examples 1 to 5 are less likely to have both durability and reworkability under harsh environments (high temperature, high humidity, and thermal shock) I knew I could not.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (26)

A pressure-sensitive adhesive composition for an optical film comprising a (meth) acrylate copolymer (A), a peroxide (B), a crosslinking agent (C) other than a peroxide, and a solvent (D)
The content of the peroxide (B) is not less than 2.0 parts by mass and not more than 10 parts by mass based on 100 parts by mass of the (meth) acrylate copolymer (A)
The cross-linking agent (C) other than the peroxide does not contain a block isocyanate compound,
The (meth) acrylate copolymer (A) has a weight average molecular weight by gel permeation chromatography (GPC) of 300,000 or more and 1,200,000 or less,
Wherein the content of solids including the (meth) acrylate copolymer (A) in the pressure-sensitive adhesive composition for an optical film is 20 mass% or more based on the total mass of the pressure-sensitive adhesive composition for an optical film,
The content of the solvent (D) in the pressure-sensitive adhesive composition for an optical film is 80 mass% or less based on the total mass of the pressure-sensitive adhesive composition for an optical film,
A pressure-sensitive adhesive composition for an optical film having a viscosity at 23 캜 of not less than 200 mPa s and not more than 5000 mPa 측정 as measured by a B-type viscometer (number of revolutions: 20 rpm) of the pressure-sensitive adhesive composition for an optical film.
A pressure-sensitive adhesive composition for an optical film comprising a (meth) acrylate copolymer (A), a peroxide (B), a crosslinking agent (C) other than a peroxide, and a solvent (D)
The peroxide (B) has a one-minute half-life temperature of 80 ° C or more and 125 ° C or less,
The cross-linking agent (C) other than the peroxide does not contain a block isocyanate compound,
The (meth) acrylate copolymer (A) has a weight average molecular weight by gel permeation chromatography (GPC) of 300,000 or more and 1,200,000 or less,
Wherein the content of solids including the (meth) acrylate copolymer (A) in the pressure-sensitive adhesive composition for an optical film is 20 mass% or more based on the total mass of the pressure-sensitive adhesive composition for an optical film,
The content of the solvent in the pressure-sensitive adhesive composition for an optical film is 80 mass% or less based on the total mass of the pressure-sensitive adhesive composition for an optical film,
A pressure-sensitive adhesive composition for an optical film having a viscosity at 23 캜 of not less than 200 mPa s and not more than 5000 mPa 측정 as measured by a B-type viscometer (number of revolutions: 20 rpm) of the pressure-sensitive adhesive composition for an optical film.
The positive resist composition as claimed in claim 1 or 2, wherein the (meth) acrylate copolymer (A) comprises (a1) a structural unit derived from an alkyl (meth)
(a2) a constituent unit derived from a (meth) acrylate monomer having a hydroxyl group, and (a3) a constituent unit derived from a monomer having a carboxyl group.
The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the content of the crosslinking agent (C) other than the peroxide is 0.001 part by mass or more and 2 parts by mass or less based on 100 parts by mass of the (meth) acrylate copolymer (A) Composition.
The pressure-sensitive adhesive composition for an optical film according to claim 1 or 2, wherein the (meth) acrylate copolymer (A) further comprises (a4) a structural unit derived from an aromatic-containing (meth) acrylate.
A pressure-sensitive adhesive composition for optical films according to any one of claims 1 to 3, further comprising 0.01 parts by mass or more and 1 part by mass or less of a silane coupling agent (E) based on 100 parts by mass of the (meth) acrylate copolymer (A) Composition.
The pressure-sensitive adhesive composition for an optical film according to claim 1 or 2, further comprising a silicate oligomer (F) having a structure represented by the following formula (1):
&Lt; Formula (1) >

R ¹ and R ² each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group, X ¹ and X ² each independently represent a hydrogen atom, a carbon number of 1 to 20 And n is an integer of 1 or more and 100 or less.
The pressure-sensitive adhesive composition for an optical film according to claim 7, wherein the silicate oligomer (F) comprises a methyl silicate oligomer.
The pressure-sensitive adhesive composition for an optical film according to claim 7 or 8, wherein the silicate oligomer (F) has a weight average molecular weight of 300 or more and 30000 or less.
The method according to any one of claims 1 to 3, wherein the crosslinking agent (C) other than the peroxide is selected from the group consisting of an isocyanate crosslinking agent, a carbodiimide crosslinking agent, an oxazoline crosslinking agent, an epoxy crosslinking agent and an aziridine crosslinking agent excluding a block isocyanate compound And at least one member selected from the group consisting of the above-mentioned components.
The pressure-sensitive adhesive composition for an optical film according to claim 10, wherein the isocyanate-based crosslinking agent comprises an isocyanate compound having a number-average molecular weight of 900 or more and 10,000 or less (excluding a block isocyanate compound).
The pressure-sensitive adhesive composition for an optical film according to claim 1 or 2, further comprising a high softening point resin (G).
The pressure-sensitive adhesive composition for an optical film according to claim 12, wherein the high softening point resin (G) is a rosin ester-based resin.
The pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 3, wherein the copolymer (A) contains a structural unit (a ') derived from a (meth) acrylic monomer having a glass transition temperature of 50 ° C or higher.
The positive resist composition according to any one of claims 1 to 3, which further comprises (meth) acryl-based structural units having a weight average molecular weight (Mw) smaller than that of the (meth) acrylate copolymer (A) (Co) polymer (H) containing a (meth) acrylic polymer (co) polymer.
The pressure-sensitive adhesive composition for optical films according to claim 15, wherein the (meth) acrylic (co) polymer (H) has a weight average molecular weight (Mw) of 500 or more and 100,000 or less.
A pressure-sensitive adhesive layer for an optical film, formed from the pressure-sensitive adhesive composition for an optical film according to claim 1 or 2.
The pressure-sensitive adhesive layer for an optical film according to claim 17, wherein the pressure-sensitive adhesive layer for an optical film has a warp of less than 1.5 mm and a pressure of less than 5 탆.
A pressure-sensitive adhesive layer for an optical film according to claim 17,
And a first optical film formed on one side of the pressure-sensitive adhesive layer.
The optical member according to claim 19, further comprising a glass or a second optical film on a surface of the pressure-sensitive adhesive layer opposite to the surface on which the first optical film is formed.
The optical member according to claim 19, further comprising at least one adhesion-treated layer between the first optical film and the pressure-sensitive adhesive layer for the optical film.
The optical film according to claim 21, further comprising a first adhesive treatment layer on the side of the first optical film facing the pressure-sensitive adhesive layer for optical film,
And a second adhesive treatment layer on the side of the pressure-sensitive adhesive layer for optical film opposite to the first optical film.
The optical member according to claim 19, wherein the first optical film is a polarizing plate.
20. An image display apparatus comprising at least one optical member according to claim 19.
A process for producing a pressure-sensitive adhesive layer for an optical film, which comprises applying a pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 3 on a release sheet subjected to a release treatment,
The method of producing a pressure-sensitive adhesive layer for an optical film according to claim 25, wherein the temperature of the heat treatment is not less than 80 ° C and not more than 120 ° C.