JP2019099714A - Adhesive composition for optical film, adhesive layer, optical member, and image display device - Google Patents

Abstract

To provide a means capable of improving durability under severe environment and reworkability, sufficiently suppressing light leakage and further suppressing both of warpage and dent while maintaining processability.SOLUTION: There is provided an adhesive composition for optical film containing a (meth)acrylate copolymer (A) containing at least one kind of constitutional unit selected from a group consisting of (a1) a constitutional unit derived from an alkyl (meth)acrylate monomer, (a2) a constitutional unit derived from a (meth)acrylate monomer having a hydroxyl group of 0.01 to 10 mass% based on total amount 100 mass% of the constitutional units, and (a3) a constitutional unit derived from a monomer having a carboxyl group, a polyrotaxane compound (B) having cyclic oligosaccharide having a hydroxyl group as a reactive group as a cyclic molecule, a crosslinking agent (C) and a solvent (D), in which the (meth)acrylate copolymer (A) has weight average molecular weight by a gel permeation chromatography (GPC) of 300,000 to 1,200,000, solid component content containing the (meth)acrylate copolymer (A) in the adhesive composition for optical film is 20 mass% or more based on total mass of the adhesive composition for optical film, content of the solvent (D) in the adhesive composition for optical film is 80 mass% or less based on total mass of the adhesive composition for optical film, and viscosity at 23°C measured by a B type viscometer (rotation number 20 rpm) of the adhesive composition for optical film is 200 mPa s to 5000 mPa s.SELECTED DRAWING: None

Description

  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 from the pressure-sensitive adhesive composition for an optical film, an optical member using the pressure-sensitive adhesive layer, and an image display device using the optical member.

  In addition to essential polarizing films (polarizing plates), various optical members such as optical films are attached to liquid crystal panels such as liquid crystal display devices, which are a type of image display device, in addition to essential polarizing films (polarizing plates) It is done. When sticking optical members, such as an optical film, to a liquid crystal panel, or when sticking two or more same or different optical films together, a pressure sensitive adhesive is usually used.

  As a necessary property of the pressure-sensitive adhesive, the durability of the pressure-sensitive adhesive in the adhesion state that no problems such as peeling or floating due to the pressure-sensitive adhesive occur in the endurance test by heating and humidification usually performed as an environmental acceleration test. Is required. In particular, in recent years, optical films used in automotive panels are required to be free from problems such as foaming or peeling due to adhesives in durability tests under higher temperature and high humidity environments than conventional ones. ing.

  In addition, when the optical film is bonded to the liquid crystal panel using an adhesive, the optical film is peeled off from the liquid crystal panel if the bonded position is incorrect or foreign matter bites into the bonding surface. And it is necessary to perform pasting again. In particular, in recent years, in addition to conventional liquid crystal display device manufacturing processes, use of liquid crystal display devices such as thin liquid crystal panels using chemically etched glass has been increasing, and optical films have also become thin and brittle. . When such a thin liquid crystal display device or thin optical film is used with an adhesive aiming only for the conventional durability, the thin liquid crystal display device or thin optical film may be broken or broken. The problem came out. For this reason, in such a peeling process, there is a demand for the property of an adhesive having removability (also referred to as "reworkability") capable of easily peeling the optical film without adhesive residue from the liquid crystal display or the like. ing. In addition, in a thin liquid crystal panel, the optical film warps due to expansion or contraction due to heating, humidification, etc., causing a problem such as contact with a frame to degrade display quality. . However, when the stress relaxation property of the pressure-sensitive adhesive is increased in order to reduce expansion or contraction due to heating and humidification, the processability and the dents are deteriorated, and the percent defective in the process is deteriorated.

  In addition, with adhesive type optical films used for highly versatile products such as for television (TV), it is required to further reduce the manufacturing cost, and it is necessary to increase the line speed of adhesive production. ing. As described above, it is possible to simultaneously suppress warping and denting after securing processability, and it is high in durability and reworkability, and has excellent handling in the manufacturing process, and is a good quality adhesive optical There is a need for an optical film pressure sensitive adhesive that can obtain a film.

  As such a pressure-sensitive adhesive, for example, Patent Document 1 discloses an acrylic polymer having a weight-average molecular weight of 500,000 to 1,000,000, which is obtained by copolymerizing n-butyl acrylate, a hydroxyl group-containing monomer, and other monomers. An adhesive composition for an optical member comprising the acrylic polymer, 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 Disclosed is a composition having a weight percent or less and a viscosity at 23 ° C. at 100 rpm of B-type viscosity meter of 8 Pa · s or less.

  In addition, Patent Document 2 describes a pressure-sensitive adhesive composition for an optical film containing a (meth) acrylic polymer and a solvent, wherein the (meth) acrylic polymer does not contain a carboxyl group-containing monomer as a monomer unit, An alkyl (meth) acrylate, a polymerizable aromatic ring-containing monomer, and a hydroxyl group-containing monomer are copolymerized, and the weight average molecular weight is 300,000 to 1,200,000, and the solid content contains the (meth) acrylic polymer Disclosed are compositions wherein the amount is 20% by weight or more and the content of the solvent is 80% by weight or less.

  Furthermore, Patent Document 3 describes a pressure-sensitive adhesive composition for an optical film containing a (meth) acrylic polymer and a solvent, wherein the (meth) acrylic polymer is an alkyl (meth) acrylate, a polymerizable aromatic ring-containing monomer And a hydroxyl group-containing monomer and a carboxyl group-containing monomer, and having a weight average molecular weight of 300,000 to 1,200,000 and a solid content of 20% by weight or more containing the (meth) acrylic polymer There is disclosed a composition in which the content of the solvent is 80% by weight or less.

JP 2011-057794 JP 2012-140578 A JP 2012-140579 A

  However, according to the study of the present inventors, even with the pressure-sensitive adhesive compositions described in Patent Documents 1 to 3, the durability (high temperature, high humidity, heat shock) under severe environment (high temperature, high humidity, heat shock) It has been found that the foam resistance in the above, floating or peeling from the adherend under high temperature and high humidity, etc., reworkability (processability) may not be sufficient, or light leakage may occur. Furthermore, it has been found that in addition to the cases where the durability, reworkability and light leakage are not sufficient, the occurrence of warpage and dents may not be suppressed.

  The present invention has been made in view of the above circumstances, and in the pressure-sensitive adhesive composition for an optical film, after securing processability, durability (high temperature, high humidity, heat shock) under severe environment (high temperature, high humidity) Resistance to foaming, floating and peeling from adherends under high temperature and high humidity, and reworkability (processability), and light leakage is also sufficiently suppressed, and warpage and dents are further suppressed. It aims at providing a means which can control both.

  MEANS TO SOLVE THE PROBLEM As a result of conducting earnest research in order to solve the said subject, the present inventors discover that the said subject can be solved with the adhesive composition which has a specific structure, and came to complete this invention.

  That is, the present invention provides (a1) a structural unit derived from an alkyl (meth) acrylate monomer, and (meth) acrylate having 0.01 to 10% by mass of (a2) hydroxyl group based on 100% by mass of the total constituent units. At least one structural unit selected from the group consisting of a structural unit derived from a monomer, and a structural unit derived from a monomer having 0.01 to 7% by mass of (a3) a carboxyl group with respect to 100% by mass in total of the structural unit , (Meth) acrylate copolymer (A), polyrotaxane compound (B) having cyclic oligosaccharide having a hydroxyl group as a reactive group as a cyclic molecule, crosslinking agent (C), and solvent (D) It is an adhesive composition for optical films containing, Comprising: The said (meth) acrylate copolymer (A) is a gel permeation chromatography. The solid content of the (meth) acrylate copolymer (A) in the pressure-sensitive adhesive composition for an optical film, having a weight average molecular weight of 300,000 to 1,200,000 according to raffi (GPC) is the optical film The content of the solvent (D) in the pressure-sensitive adhesive composition for an optical film is 20% by mass or more based on the total weight of the pressure-sensitive adhesive composition for the total weight of the pressure-sensitive adhesive composition for an optical film To 80% by mass or less and the viscosity at 23 ° C. measured with a B-type viscometer (rotational speed 20 rpm) of the pressure-sensitive adhesive composition for an optical film is 200 mPa · s or more and 5000 mPa · s or less Agent composition.

  According to the present invention, in the pressure-sensitive adhesive composition for an optical film, after ensuring processability, durability (high temperature, high humidity, heat shock) in a severe environment (high temperature, high temperature high humidity, high temperature high humidity It is possible to provide a means capable of improving the reworkability (processability) and lifting and peeling from the adherend below and sufficiently suppressing light leakage and further suppressing both warpage and dents. .

  Hereinafter, modes 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 present invention comprises (a1) a constituent unit derived from an alkyl (meth) acrylate monomer, and 0.01 to 10% by mass of (a2) hydroxyl group based on 100% by mass of the constituent unit. Selected from the group consisting of structural units derived from (meth) acrylate monomers having a component and structural units derived from monomers having a carboxyl group (a3) of 0.01 to 7% by mass with respect to the total amount 100% by mass of the constituent units (Meth) acrylate copolymer (A) containing at least one structural unit, polyrotaxane compound (B) having a cyclic oligosaccharide having a hydroxyl group as a reactive group as a cyclic molecule, a crosslinking agent (C), It is an adhesive composition for optical films containing solvent (D), Comprising: The said (meth) acrylate copolymer (A) is a gel permi The solid content of the (meth) acrylate copolymer (A) in the pressure-sensitive adhesive composition for an optical film, having a weight average molecular weight of 300,000 to The content of the solvent (D) in the pressure-sensitive adhesive composition for optical films is 20% by mass or more based on the total mass of the pressure-sensitive adhesive composition for optical films, the content of the solvent (D) in the pressure-sensitive adhesive composition for optical films It is 80 mass% or less with respect to the total mass, and the viscosity at 23 ° C. measured by a B-type viscometer (rotational speed 20 rpm) of the pressure-sensitive adhesive composition for an optical film is 200 mPa · s or more and 5000 mPa · s or less.

  According to the pressure-sensitive adhesive composition for an optical film of the present invention having such a constitution, the processability is ensured, and then the durability (high temperature, high humidity, heat shock) in a severe environment (high temperature, high humidity) And improve reworkability (processability) while sufficiently suppressing light leakage as well as suppressing both warpage and dents. be able to.

  Hereinafter, each component which comprises the adhesive composition for optical films which concerns on this invention is demonstrated in order.

  In the present specification, "(meth) acrylate" is a generic term for acrylate and methacrylate. The compound etc. which contain (meth), such as (meth) acrylic acid, are a generic term of the compound which has "meta" in a name, and the compound which does not have "meta" similarly. Moreover, "(meth) acrylate copolymer (A)" is also called "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 copolymer (A) reacts with the crosslinker (C) together with the polyrotaxane compound (B) to form a crosslinked structure, thereby exhibiting adhesiveness (adhesiveness).

  The weight average molecular weight (Mw) by gel permeation chromatography (GPC) of the copolymer (A) according to the present invention is 300,000 or more and 1.2,000 or less. When the weight average molecular weight (Mw) is less than 300,000, dents occur, and the durability at high temperatures and the reworkability after heating are reduced. On the other hand, if it exceeds 1.2 million, warpage occurs.

  The weight average molecular weight (Mw) of the copolymer (A) by gel permeation chromatography (GPC) is preferably 300,000 or more and less than 1,000,000, and more preferably 400,000 or more and 950,000 or less. More preferably, it is 10,000 or more and 900,000 or less. When the Mw of the copolymer (A) is in the above range, the molecular weight of the component (A) is small by adjusting the solid content and solvent amount of the component (A) and further the viscosity of the pressure-sensitive adhesive composition, By cross-linking with a polyrotaxane compound (B) with a crosslinking agent (C) to form a network and apply a network (to form a network), conventionally, when a low molecular weight component (A) in the above range is used, high temperature Thus, it has been found that the special effect that the material which has been peeled off as soon as the shrinkage of the polarizing plate becomes large can be hardly peeled off. Further, the effect of the low molecular weight of the component (A) is also excellent in suppressing the occurrence of warpage, and although it is low in molecular weight, it is also excellent in the occurrence suppressing effect of the dent due to the presence of the network structure. In addition, the effect of lowering the molecular weight of the component (A) and adjusting the viscosity etc. is also excellent in the effect of greatly improving the productivity at the time of coating. Thus, in addition to the durability (peeling suppression effect) under severe environments and the significant improvement effect of the productivity at the time of coating, it is preferable from the viewpoint that the balance of the generation suppressing effect of warpage and dents is particularly excellent. The weight average molecular weight (Mw) of the copolymer (A) of the present invention appropriately adjusts the type and / or amount of the polymerization initiator used in the polymerization reaction described later, reaction conditions such as reaction temperature, reaction time, etc. This allows the person skilled in the art to easily control.

  Further, the number average molecular weight (Mn) by gel permeation chromatography (GPC) of the copolymer (A) according to the present invention is not particularly limited, but the effect of significantly improving the durability and the productivity at the time of coating is In addition, from the viewpoint that the balance between the warpage and the generation of the dents suppressing effect is particularly excellent, it is preferably 50,000 or more and 400,000 or less, more preferably 70,000 or more and 300,000 or less, and more preferably 80,000 or more and 200,000 or less. Is particularly preferred. Further, the number average molecular weight (Mn) of the copolymer (A) of the present invention can be determined by appropriately adjusting the polymerization initiator used in the polymerization reaction described later, the reaction conditions such as the reaction temperature and the reaction time, etc. If it is, it can control easily.

  Further, the degree of dispersion (Mw / Mn) of the copolymer (A) according to the present invention is not particularly limited, but durability and reworkability are compatible, and further, the effect of largely improving the productivity at the time of coating is achieved. In addition, from the viewpoint that the balance between the warpage and the nicking generation suppressing effect is particularly excellent, it is preferably 2.0 or more and 20 or less, more preferably 2.5 or more and 15 or less, and 3.0 or more and 10 or less Is particularly preferred.

  The weight average molecular weight (Mw), the number average molecular weight (Mn), and the degree of dispersion (Mw / Mn) of the copolymer (A) can be measured by gel permeation chromatography (GPC), as described in detail. Can be measured by the method shown in the examples.

In the present invention, as a constituent unit constituting the copolymer (A),
(A1) Structural unit derived from alkyl (meth) acrylate monomer (hereinafter, also simply referred to as “component (a1)”), and (a2) structural unit derived from (meth) acrylate monomer having a hydroxyl group (hereinafter referred to simply as “component And (a3) at least one structural unit selected from the group consisting of structural units derived from monomers having a carboxyl group (hereinafter, also simply referred to as "component (a3)"). That is, the copolymer (A) according to the present invention preferably comprises the component (a1) and the component (a2); preferably also comprises the component (a1) and the component (a3); and further the component (a1), It is also preferred to include component (a2) and component (a3).

In the present specification, for example, “the copolymer X contains a constitutional unit derived from the monomer Y _{1 and} a constitutional unit derived from the monomer Y ₂ ” is used when obtaining the copolymer X by copolymerization It means that the monomer Y ₁ and the monomer Y ₂ are included as raw material monomers.

  Hereinafter, the structural unit derived from each monomer which can comprise the copolymer (A) concerning this invention is demonstrated in order.

[Constituent unit derived from (a1) alkyl (meth) acrylate monomer]
The copolymer (A) according to the present invention preferably contains a structural unit derived from (a1) alkyl (meth) acrylate monomer (hereinafter, also simply referred to as “component (a1)”). Such a component (a1) is considered to have a meaning of securing adhesiveness and securing basic characteristics by being included as a constituent unit of the (meth) acrylate copolymer (A) according to the present invention.

  In the present invention, the structure of the alkyl (meth) acrylate monomer is not particularly limited, and is not particularly limited as long as an alkyl group is introduced to the ester site of (meth) acrylate.

  The carbon number of the alkyl group is not particularly limited, but is preferably 1 or more and 20 or less, more preferably 1 or more and 12 or less, and 1 or more and 10 or less from the viewpoint of versatility, price and handling. Is more preferably, 1 to 8 is more preferable, and 1 to 6 is particularly preferable. The alkyl group may be linear, branched or cyclic, but is preferably linear or branched from the viewpoint of lowering the glass transition temperature. When the alkyl group is cyclic, the carbon number is 3 or more.

  The alkyl group is not particularly limited, but methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group, isobutyl group, n-pentyl group, isopentyl group, n -Hexyl group, 2-hexyl group, 3-hexyl group, cyclohexyl group, 1-methylcyclohexyl group, n-heptyl group, 2-heptyl group, 3-heptyl group, isoheptyl group, t-heptyl group, n-octyl group , Isooctyl group, t-octyl group, 2-ethylhexyl group, nonyl group, isononyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, cyclohexyl group, etc. It can be mentioned. In particular, 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 securing adhesiveness and basic properties.

  Thus, specific examples of the alkyl (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate and isobutyl (meth) Acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, Nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, cyclohexyl (meth) acrylate and the like can be mentioned. Among them, methyl (meth) acrylate and n-butyl (meth) acrylate are preferable from the viewpoint of improvement in heating durability and adhesion (particularly reworkability). Component (a1) can be used alone or as a mixture of two or more.

  The content of the component (a1) in the copolymer (A) according to the present invention (the compounding amount of the alkyl (meth) acrylate monomer as the raw material monomer) is not particularly limited, but the content of other raw material monomers described later 64.5% by mass or more and 99.5% by mass with respect to 100% by mass of the constituent units constituting the (meth) acrylate copolymer (A), from the viewpoint of, for example, a good balance of It is preferable that it is less than%, it is more preferable that it is 80 to 99 mass%, and it is especially preferable that it is 85 to 99 mass%. In the present specification, “total amount of 100% by mass of the constituent units constituting the (meth) acrylate copolymer (A)” means that when the (meth) acrylate copolymer (A) is obtained by copolymerization, It means that the total amount of all the raw material monomers used is 100% by mass.

[Constituent unit derived from (meth) acrylate monomer having (a2) hydroxyl group]
The copolymer (A) according to the present invention preferably contains a structural unit derived from a (meth) acrylate monomer having a (a2) hydroxyl group (hereinafter, also simply referred to as "component (a2)"). Since such a component (a2) is rich in the reactivity with the crosslinking agent, the cohesiveness and heat resistance of the pressure-sensitive adhesive layer described later can be obtained by being contained as a constituent unit of the copolymer (A) according to the present invention. It is considered to have a meaning to improve. Also, according to the studies of the present inventors, the component (a2) of the copolymer (A) can react with the crosslinking agent (C) according to the present invention, and the crosslink density of the adhesive layer described later It turned out that the rising pressure-sensitive adhesive layer becomes hard and the deformation amount of the pressure-sensitive adhesive layer at the time of re-peeling becomes small, whereby the adhesive strength is lowered, desired reworkability is obtained, and peeling can be suppressed even in durability. Furthermore, it also turned out that generation | occurrence | production of curvature and a dent can be suppressed by making the weight average molecular weight of a copolymer (A), the viscosity of a composition, etc. into the range of this invention.

  In the present invention, the structure of the (meth) acrylate monomer having a hydroxyl group is not particularly limited, and is not particularly limited as long as the hydroxyl group is introduced into a part of the (meth) acrylate monomer.

  Specific examples of the (meth) acrylate monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate 2.) Acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, hydroxymethyl (meth) acrylate Amide, hydroxyethyl (meth) acrylamide, cyclohexane dimethanol monoacrylate and the like, and addition of glycidyl group-containing compounds such as alkyl glycidyl ether, allyl glycidyl ether, glycidyl (meth) acrylate and (meth) acrylic acid The compound etc. which are obtained by reaction are mentioned. Among them, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylamide and cyclohexane dimethanol monoacrylate are preferable from the viewpoint of efficiently functioning as a crosslinking point. Hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are more preferred. These components (a2) can be used alone or in combination of two or more.

  When the copolymer (A) according to the present invention contains the component (a2), the content of the component (a2) (the compounding amount of the (meth) acrylate monomer having a hydroxyl group as the raw material monomer) is It is 0.01 mass% or more and 10 mass% or less with respect to 100 mass% of whole constituent units which constitute A). If the content of the component (a2) is less than 0.01% by mass, the crosslinking reaction site becomes too small, and the durability is deteriorated. On the other hand, when the content of the component (a2) exceeds 10% by mass, the proportion of the polar monomer to be blended relatively increases, the polarity of the formed pressure-sensitive adhesive layer also increases, and the durability decreases. The content of the component (a2) is preferably 0.3% by mass or more and 5% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less.

[(A3) Structural Unit derived from Monomer Having Carboxyl Group]
In the present invention, the copolymer (A) preferably contains a structural unit derived from a monomer having a carboxyl group (a3) (hereinafter, also simply referred to as “component (a3)”). Such component (a3) can contribute mainly to the improvement of durability and reworkability 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 may be any structure as long as it contains a carboxyl group and a polymerizable unsaturated bond in the structure.

  Specific examples of the monomer having a carboxyl group include (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, itaconic acid, itaconic acid, myristoleic acid, palmitoleic acid, and olein. An acid etc. are mentioned. Among them, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, itaconic acid, anhydride, from the viewpoint of excellent copolymerizability with other (meth) acrylic monomers. Itaconic acid is preferred, and (meth) acrylic acid is more preferred. These components (a3) can be used alone or in combination of two or more.

  When the copolymer (A) according to the present invention contains the component (a3), the content of the component (a3) (the compounding amount of the hydroxyl group-containing (meth) acrylate monomer as the raw material monomer) It is 0.01 mass% or more and 7 mass% or less with respect to 100 mass% of whole constituent units which constitute A). If the content of the component (a3) is less than 0.01% by mass, the crosslinking reaction site becomes too small, and the durability is lowered. On the other hand, when the content of the component (a3) exceeds 7% by mass, the proportion of the polar monomer to be blended relatively increases, the polarity of the formed pressure-sensitive adhesive layer also increases, and the durability decreases. The content of the component (a3) is preferably 0.2% by mass or more and 5% by mass or less, and more preferably 0.6% by mass or more and 5% by mass or less.

[(A4) Structural unit derived from (meth) acrylate monomer having an aromatic ring]
The copolymer (A) according to the present invention preferably further includes (a4) a structural unit derived from a (meth) acrylate monomer having an aromatic ring (hereinafter, also simply referred to as “component (a4)”). Such component (a4) can mainly contribute to suppression of light leakage in the pressure-sensitive adhesive composition for an optical film.

  In the present invention, the structure of the (meth) acrylate monomer having an aromatic ring is not particularly limited, as long as it contains an aromatic ring (aromatic ring) and a (meth) acryloyl group in the structure. It may be one. Here, 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 aromatic ring-containing (meth) acrylate monomer include benzyl (meth) acrylate, phenyl (meth) acrylate, o-phenylphenol (meth) acrylate phenoxy (meth) acrylate, p-t-butylphenyl (meth) Acrylate, phenoxyethyl (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide modified nonylphenol (meth) acrylate, ethylene oxide modified cresol (meth) acrylate, phenol ethylene oxide modified (meth) acrylate, 2-hydroxy -3-Phenoxypropyl (meth) acrylate, methoxybenzyl (meth) acrylate, chlorobenzyl (meth) acrylate, cu Those having a benzene ring such as zyl (meth) acrylate and polystyryl (meth) acrylate; hydroxyethylated β-naphthol acrylate, 2-naphthoethyl (meth) acrylate, 2-naphthoxyethyl acrylate, 2- (4-methoxy-1) Those having a naphthalene ring such as naphthoxy) ethyl (meth) acrylate; and those having a biphenyl ring such as biphenyl (meth) acrylate. Among them, benzyl (meth) acrylate and phenoxyethyl (meth) acrylate are preferable from the viewpoint of suppressing light leakage and easily ensuring durability. These components (a4) may be used alone or in combination of two or more.

  The content of the component (a4) in the copolymer (A) according to the present invention (the blended amount of the (meth) acrylate monomer having an aromatic ring as a raw material monomer) is not particularly limited, but light leakage can be sufficiently suppressed. And, from the viewpoint of sufficiently securing the durability, preferably from 0% by mass to 30% by mass with respect to 100% by mass of the constituent units constituting the (meth) acrylate copolymer (A). And 10% by mass or more and 20% by mass or less.

[(A5): constituent unit derived from a monomer other than the components (a1) to (a4)]
The copolymer (A) according to the present invention is a constituent unit derived from a monomer other than the components (a1) to (a4) which can be copolymerized with the components (a1) to (a4) described above as optional components (hereinafter referred to as It can contain only "component (a5)".

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

  Examples of raw material monomers of the component (a5) include acrylic monomers having an epoxy group such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (Meth) acrylic monomers having an amino group such as N-t-butylaminoethyl (meth) acrylate and (meth) acryloyloxyethyl trimethyl ammonium chloride; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N, N-methylene bis (meth) acrylamide, (Meth) acrylic monomers having an amide group such as methylaminopropyl (meth) acrylamide and diacetone (meth) acrylamide; 2-methacryloyloxyethyl diphenyl phosphate (meth) acrylate, trimethacryloyl oxyethyl phosphate (meth) acrylate, (Meth) acrylic monomers having a phosphate group such as triacryloyloxyethyl phosphate (meth) acrylate; sodium sulfopropyl (meth) acrylate, sodium 2-sulfoethyl (meth) acrylate, 2-acrylamido-2-methylpropane sulfonic acid (Meth) acrylic monomers having sulfonic acid groups such as sodium; (meth) acrylic monomers having urethane groups such as urethane (meth) acrylates; 2-acetoacetoxy Vinyl monamers having a silane group such as ethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethyl) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane, etc .; styrene, chlorostyrene, α -Methylstyrene, vinyl toluene, vinyl chloride, vinyl acetate, vinyl propionate, acrylonitrile, vinyl pyridine, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth) acryloyl moro Forin, 2- (meth) acryloyloxyethyl phthalic acid, tetrahydrofurfuryl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, (meth) Acryloyl morpholine, and the like.

  Moreover, as a raw material monomer of a component (a5), the (meth) acrylate monomer which has an alkoxy alkyl group or an alkylene oxide group is also used suitably.

  Examples of (meth) acrylate monomers having an alkoxyalkyl group or an alkylene oxide group include, for example, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxy Ethyl (meth) acrylate, methoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate; ethoxy-diethylene glycol (meth) acrylate, ethoxy-triethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, methoxy- Diethylene glycol (meth) acrylate, propoxy-diethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) Crylates, 2-ethylhexyloxy-didiethylene glycol (meth) acrylate, methoxy-polyethylene glycol (meth) acrylate (n = 4-10), methoxydipropylene glycol (meth) acrylate, 2-ethylhexyl diglycol acrylate and the like .

  The above-mentioned monomers may be used alone or in combination of two or more. In addition, when producing the (meth) acrylate copolymer (A) according to the present invention, the component (from the viewpoint that the reaction with the crosslinking agent described later can be easily controlled, the viewpoint that the molecular weight is difficult to increase, etc. The raw material monomer of a5) preferably does not contain an olefin monomer such as ethylene or propylene.

  In the copolymer (A) according to the present invention, among the components containing the (a1) to (a4) (ie, the components (a1) to (a5)), the glass transition temperature of the homopolymer is 50 ° C. It is preferable to (selectively) contain a structural unit derived from the above (meth) acrylate monomer (hereinafter, also simply referred to as "component (a ')"). Such a component (a ') can ensure the hardness of the pressure-sensitive adhesive layer at room temperature that requires pitting resistance, and softens and adheres at 80 ° C. or higher, which is a heating durability test temperature at which warping occurs. The agent layer can be made to have stress relaxation properties to suppress warpage, and the polymerizability with the (meth) acrylate monomer described above is excellent, and the durability and adhesion (particularly reworkability) are improved, It is excellent at the point which can suppress generation | occurrence | production of curvature and a dent.

((Meth) acrylic (co) polymer (I))
In the pressure-sensitive adhesive composition for an optical film according to the present invention, the weight average molecular weight (Mw) is smaller than that of the copolymer (A) and the glass transition temperature of the homopolymer is different from the copolymer (A). (Meth) acrylic (co) polymer (I) (hereinafter, also simply referred to as “(co) polymer (I)”) containing a structural unit derived from a (meth) acrylic monomer having a temperature of 50 ° C. or higher Is preferred. Such a (co) polymer (I) is similar to the copolymer (A) in the constituent unit contained, but as an acrylic resin of a low molecular weight component like high softening point resin (H) described later It exists separately. Therefore, in the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition for an optical film containing the (co) polymer (I), the (co) polymer (I) can move freely, so adhesion It is excellent at the point which becomes easy to provide stress relaxation property to an agent layer. Also, unlike the high softening point resin (H), the (co) polymer (I) is an acrylic component similar to the copolymer (A), so the compatibility is good and the adhesive layer is highly softened. As compared with the case where the point resin (H) is contained (a small amount of whitening may occur), the whitening is reduced (preferably, no whitening occurs). Therefore, by adding the above (co) polymer (I) to impart various properties as described above, it is possible to ensure the hardness of the pressure-sensitive adhesive layer at room temperature where the pitting resistance is required, and the warpage It is excellent at softening at 80 ° C. or higher, which is a test temperature of the generated heating durability, to make the pressure-sensitive adhesive layer have stress relaxation property and to suppress warpage.

(Weight-average molecular weight of (co) polymer (I))
The weight average molecular weight (Mw) of the (co) polymer (I) 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 And 800 or more and 80,000 or less is more preferable, and 1,000 or more and 50,000 or less is more preferable. The (co) polymer (I) having a molecular weight in the above-mentioned range is similar to the copolymer (A) in the constituent units contained, but is separately present as a low molecular component acrylic resin. Therefore, in the pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition for an optical film containing (co) polymer (I), the (co) polymer (I) can freely move. It is excellent at the point which becomes easy to provide stress relaxation property to an adhesive layer. In addition, since the (co) polymer (I) is an acrylic component similar to the copolymer (A), the compatibility is good and the pressure-sensitive adhesive layer is less likely to be clouded (preferably clouded). ), Which is preferable.

  In the pressure-sensitive adhesive composition for an optical film according to the present invention, the component (a ′) may be contained in the copolymer (A), or the above (co) polymer (apart from the copolymer (A) I) may be contained.

  In the pressure-sensitive adhesive composition of the present invention, the effects of the component (a ′) and the (co) polymer (I), which are components having a glass transition temperature of 50 ° C. or more of the homopolymer, can be exhibited efficiently The component having a glass transition temperature of 50 ° C. or more of the homopolymer may be a component of the (meth) acrylate copolymer (A), or the component (A) separately from the (meth) acrylate copolymer (A) It may be present as a co-polymer (I). That is, the component of the other (meth) acrylate copolymer (A) and the component (a ') may be copolymerized, or the copolymer (A) and the component (a') may be obtained by multistage polymerization. May be polymerized, or (co) polymer (I) may be blended separately from the copolymer (A).

  In the present invention, the structure of the (meth) acrylic monomer having a glass transition temperature of 50 ° C. or higher of the homopolymer used in the component (a ′) or the (co) polymer (I) is a glass transition of the homopolymer The temperature is not particularly limited as long as it is 50 ° C. or higher.

  Specific examples of the (meth) acrylic monomer constituting the (co) polymer (I) include, for example, isobonyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate and acrylonitrile (Meth) acrylamide, N-methylol (meth) acrylamide, dimethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, diacetone (meth) acrylamide, acryloyl group Morpholine, 2-methacryloyloxyethyl phthalic acid, tetrahydrofurfuryl (meth) acrylate, methyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethyl (meth) acrylate Rate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate , T-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) (Meth) acrylics such as acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, n-octadecyl (meth) acrylate Acid (carbon number To 20) alkyl esters, for example, cycloalkyl (meth) acrylates (eg, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate etc.), aralkyl (meth) acrylates (eg benzyl (meth) acrylate etc.), Polycyclic (meth) acrylates (for example, 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-nor Bornylmethyl (meth) acrylate etc., hydroxyl group-containing (meth) acrylic acid esters (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) ) Methacrylates, etc., alkoxy group or phenoxy group-containing (meth) acrylic acid esters (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (Meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate etc., epoxy group-containing (meth) acrylic acid esters (eg glycidyl (meth) acrylate etc), halogen-containing (meth) acrylic acid Esters (eg, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate Rate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate), alkylaminoalkyl (meth) acrylates (e.g., dimethylaminoethyl (meth) acrylate, etc.) and the like. These (meth) acrylic monomers may be used alone or in combination of two or more.

  An acrylic oligomer can also be used as the (co) polymer (I). Specific examples of the acrylic oligomer include, for example, “ARUFON (Alfon, registered trademark)” manufactured by Toagosei Co., Ltd., “Actflow (registered trademark)” manufactured by Soken Chemical Co., Ltd., and “JONCRYL (registered trademark) manufactured by BASF Japan Ltd. Commercially available products such as ".

  Specific examples of (meth) acrylic monomers having a glass transition temperature of 50 ° C. or higher, which are used as the component (a ′) or (co) polymer (I) described above, are shown below, but are limited thereto It is not a thing. The parenthesis indicates the glass transition temperature of the homopolymer.

  Specific examples thereof include, for example, isobonyl acrylate (94 ° C.), dicyclopentenyl acrylate (120 ° C.), dicyclopentanyl acrylate (120 ° C.), acrylonitrile (97 ° C.), acrylamide (165 ° C.), N-methylol acrylamide (150 ° C.), dimethyl acrylamide (119 ° C.), N-isopropyl acrylamide (134 ° C.), diethyl acrylamide (81 ° C.), dimethylaminopropyl acrylamide (134 ° C.), diacetone acrylamide (77 ° C.), acryloyl morpholine (145) ° C), 2-methacryloyloxyethyl phthalic acid (55 ° C), methyl methacrylate (105 ° C), ethyl methacrylate (65 ° C), t-butyl methacrylate (107 ° C), cyclohexyl methacrylate ( 6 ° C), tetrahydrofurfuryl methacrylate (60 ° C), benzyl methacrylate (54 ° C), isobornyl methacrylate (180 ° C), dicyclopentenyloxyethyl methacrylate (50 ° C), dicyclopentanyl methacrylate (175 ° C), etc. Can be mentioned. These may be used alone or in combination of two or more.

  The content of the component (a ′) in the copolymer (A) according to the present invention (the compounding amount of the (meth) acrylic monomer whose glass transition temperature of the homopolymer as the raw material monomer is 50 ° C. or more) is the present invention From the viewpoint of achieving the effect of (1) more efficiently, the amount is preferably 0% by mass or more and 20% by mass or less, more preferably 0.1% by mass with respect to 100% by mass of the constituent units constituting the copolymer (A). The content is not less than 15% by mass, particularly preferably not less than 0.5% by mass and not more than 10% by mass. If the content of the component (a ') is 20% by mass or less, it is preferable in that coexistence of suppression of a nick and warpage becomes easier.

  The content of the (co) polymer (I) according to the present invention is preferably 20% by mass, based on 100% by mass of the total amount of the pressure-sensitive adhesive composition for an optical film, from the viewpoint of exhibiting the effects of the present invention more efficiently. Or less, more preferably 0.1% by mass or more and 15% by mass or less, and particularly preferably 0.5% by mass or more and 10% by mass or less. When the content of the (co) polymer (I) is 20% by mass or less, an advantage such as easy suppression of both nicks and warpage can be obtained.

  The glass transition temperature of the homopolymer may be 50 ° C. or higher, but the glass transition temperature is preferably 50 ° C. or higher and 200 ° C. or lower, from the viewpoint of facilitating balance between the depression and the warpage. ° C or more and 150 ° C. or less are more preferable, and 60 ° C. or more and 120 ° C. or less are more preferable. The said glass transition temperature is a value measured by the differential scanning calorimetry analysis of the said homopolymer (homopolymer).

  The copolymer (A) and the (co) polymer (I) described above can be used alone or in combination of two or more.

[Method for producing (meth) acrylate copolymer (A)]
Next, the method for producing the copolymer (A) will be described. In the present invention, the method for producing the copolymer (A) is not particularly limited, and solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, reverse phase suspension polymerization, thin film using a polymerization initiator A conventionally known method such as a polymerization method or a spray polymerization method can be used. As a method of polymerization control, adiabatic polymerization method, temperature control polymerization method, isothermal polymerization method and the like can be mentioned. The polymerization initiator may be either a thermal polymerization initiator or a photopolymerization initiator. In addition to or in addition to the method of initiating the polymerization by the polymerization initiator, a method of initiating the polymerization by irradiating an active energy ray such as a radiation, an electron beam or an ultraviolet ray can also be adopted. Among them, a solution polymerization method using a thermal polymerization initiator or a bulk polymerization method using a photopolymerization initiator is more preferable because the molecular weight can be easily controlled and impurities can be reduced.

  In the solution polymerization method using a thermal polymerization initiator, a thermal polymerization initiator is added to a monomer solution serving as a raw material of the copolymer (A), for example, a raw material monomer solution composed of the above-described monomer, to carry out a polymerization reaction. More specifically, 0.01 to 1 part by mass of a thermal polymerization initiator is preferably added to 100 parts by mass of a total amount of raw material monomers using ethyl acetate, toluene, methyl ethyl ketone, acetone or the like as a solvent. And the reaction temperature is 40 ° C. or more and 90 ° C. or less (or 60 ° C. or more and 90 ° C. or less), for example, 3 hours or more and 10 hours or less.

  As a thermal polymerization initiator, for example, 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-methyl propionate), 2,2'- Azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2 '-Azobis (N-butyl-2-methylpropionamide), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-a Bis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl)- 2-Methylpropionamidine] hydrate, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) Azo compounds such as dihydrochloride, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], etc .; t-butyl peroxypivalate, t-butyl peroxybenzoate, t-butyl peroxy -2-ethylhexanoate, di-t-butyl peroxide, cumene hydroperoxide, benzene Organic peroxides such as nzoyl peroxide and t-butyl hydroperoxide; and inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate and sodium persulfate. These thermal polymerization initiators can be used alone or as a mixture of two or more.

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

Examples of active energy rays used in bulk polymerization include, for example, ultraviolet rays, laser rays, α rays, β rays, γ rays, X rays, electron rays, etc., but they have good controllability and handleability, and cost. Ultraviolet light is preferably used in view of the above. More preferably, ultraviolet light having a wavelength of 200 nm or more and 400 nm or less is used. Ultraviolet light can be emitted using a light source such as a high pressure mercury lamp, a microwave excitation lamp, a chemical lamp, or a black light. The illuminance is preferably 3.2 mW / cm ² or more and 5.6 mW / cm ² or less.

  As the photopolymerization initiator, for example, acetophenone, 3-methylacetophenone, benzyl dimethyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- (4-isopropylphenyl) -2-hydroxy- 2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one and the like Acetophenones: benzophenone, 4-chlorobenzophenone, benzophenone including 4,4'-diaminobenzophenone; benzoin ethers such as benzoin propyl ether, benzoin ethyl ether; thioxanthones such as 4-isopropyl thioxanthone; 1-hydroxy Cyclohexylpheny Ketone, xanthone, fluorenone, camphor quinone, benzaldehyde, such as anthraquinone, and the like. One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination.

  The photopolymerization initiator may be a commercially available product, and examples of commercially available products include IRGACURE (registered trademark) 184, 819, 907, 651, 1700, 1800, 819, 369, 261, DAROCURE (registered trademark) TPO. 1173 (above, BASF Japan Ltd.), Ezacure (registered trademark) KIP 150, TZT (above, DKSH Japan Ltd.), Kayacure (registered trademark) BMS, DMBI (above, Nippon Kayaku Co., Ltd.), etc. It can be mentioned.

  The amount of the photopolymerization initiator used is preferably 0.0005 to 1 part by mass, more preferably 0.002 to 0.5 parts by mass with respect to 100 parts by mass of the total amount of raw material monomers. is there.

  Chain transfer agents can also be used to control the molecular weight of the copolymer (A). For example, methyl mercaptan, t-butyl mercaptan, decyl mercaptan, benzyl mercaptan, stearyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid and esters thereof, 2-ethylhexyl thioglycol, octyl thioglycolate, etc. Mercaptans; alcohols such as methanol, ethanol, propanol, n-butanol, isopropanol, t-butanol, hexanol, benzyl alcohol and allyl alcohol; halogenated hydrocarbons such as chlorethane, fluoroethane and trichloroethylene; acetone, methyl ethyl ketone, Cyclohexanone, acetophenone, acetaldehyde, propionaldehyde, n-butyraldehyde Furfural, carbonyls, such as benzaldehyde; methyl-4-cyclohexene-1,2-dicarboxylic acid anhydride, such as α- methyl styrene. These chain transfer agents can be used alone or in combination of two or more.

  The method for producing the (co) polymer (I) is the same as the method for producing the above-mentioned copolymer (A) except that the type and amount of the monomers, the amount of the polymerization initiator used and the like are changed. It is similar.

<Polyrotaxane Compound (B)>
The polyrotaxane compound (B) is a compound in which a linear molecule penetrates the opening of at least two cyclic molecules and has a blocking group at both ends of the linear molecule. In this polyrotaxane compound (B), it is possible for the cyclic molecule to move freely on the linear molecule, but the blocking group has a structure in which the cyclic molecule can not escape from the linear molecule. That is, linear molecules and cyclic molecules maintain their form not by chemical bonds such as covalent bonds but by so-called mechanical structures. The pressure-sensitive adhesive composition of the present invention contains a polyrotaxane compound (B) having such a mechanical structure, and a (meth) acrylic acid ester polymer (A) and a polyrotaxane compound (B) (B) via a crosslinking agent (C) When the polyrotaxane compound (B) allows the cyclic molecule to freely move on the linear molecule, the flexibility as a crosslinked product is remarkably improved. Thereby, the pressure-sensitive adhesive composition obtained becomes excellent in durability.

  The polyrotaxane compound (B) according to the present invention has a cyclic oligosaccharide having a hydroxyl group as a reactive group as a cyclic molecule. By using a cyclic oligosaccharide having a hydroxyl group as a cyclic molecule of the polyrotaxane compound (B), it is possible to select an appropriate ring diameter, whereby the effect of the cyclic molecule moving on the linear molecule is obtained. It is easy to express. Moreover, since the said cyclic oligosaccharide has a hydroxyl group as a reactive group, reaction with a crosslinking agent (C) becomes easy. Furthermore, the introduction of various substituents and the like is also easy, which makes it possible to adjust the compatibility of the polyrotaxane compound (B) with other components by the polyrotaxane compound (B). Furthermore, cyclic oligosaccharides have the advantage of being easily available. In the present specification, "cyclic" of "cyclic molecule" or "cyclic oligosaccharide" means substantially "cyclic". That is, as long as it can move on a linear molecule, the cyclic molecule may not be completely closed, for example, may have a helical structure.

  Examples of cyclic oligosaccharides include cyclodextrins such as α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin and the like, among which α-cyclodextrin is preferred. Two or more types of cyclic molecules of the polyrotaxane compound (B) may be mixed in the polyrotaxane compound (B) or in the pressure-sensitive adhesive composition.

  The cyclic molecule (cyclic oligosaccharide) of the polyrotaxane compound (B) has a hydroxyl group as a reactive group. This hydroxyl group may be a hydroxyl group that the cyclic oligosaccharide has in its original state (which means the state before modification), or may be a hydroxyl group introduced as a substituent to the cyclic oligosaccharide.

  The lower limit value of the hydroxyl value of the cyclic molecule is preferably 10 mg KOH / g or more, more preferably 30 mg KOH / g or more, and still more preferably 50 mg KOH / g or more. The polyrotaxane compound (B) can fully react with a crosslinking agent (C) (preferably isocyanate crosslinking agent) as the lower limit of a hydroxyl value is more than the above. The upper limit of the hydroxyl value of the cyclic molecule is preferably 1000 mg KOH / g or less, more preferably 200 mg KOH / g or less, and still more preferably 100 mg KOH / g or less. If the upper limit value of the hydroxyl value is equal to or less than the above value, an appropriate crosslinking point is provided, and as a result, the durability of the pressure-sensitive adhesive layer can be secured. In addition, the said hydroxyl value can be measured by the method based on JISK0070: 1992.

  The linear molecule of the polyrotaxane compound (B) is a molecule or a substance which is included in a cyclic molecule and can be integrated not by chemical bond such as covalent bond but by mechanical bond, which is linear If it is, it will not be limited in particular. In the present specification, "linear" of "linear molecule" means that the molecule is substantially "linear". That is, a linear molecule may have a branched chain as long as the cyclic molecule can move on the linear molecule.

  Examples of linear molecules of the polyrotaxane compound (B) include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; polybutadiene diol, polyisoprene diol, polyisobutylene diol, poly (acrylonitrile-butadiene) diol Terminal hydroxyl group polyolefins such as hydrogenated polybutadiene diol, polyethylene diol, polypropylene diol; Polycaprolactone diol, polylactic acid, polyethylene adipate, polybutylene adipate, polyesters such as polyethylene terephthalate, polybutylene terephthalate; Terminal silanol type polydimethylsiloxane Terminal functional polysiloxanes such as; terminal amino group polyethylene glycol And terminal amino group chain polymers such as terminal amino group polypropylene glycol and terminal amino group polybutadiene; trifunctional or higher polyfunctional chain polymers having three or more of the above functional groups in one molecule Be Among them, polyethylene glycol and / or terminal amino group polyethylene glycol are preferably used from the viewpoint of easy availability. Two or more types of these linear molecules may be mixed in the adhesive composition.

  The lower limit value of the number average molecular weight of the linear molecule of the polyrotaxane compound (B) is preferably 3,000 or more, more preferably 5,000 or more, and still more preferably 10,000 or more. . The upper limit of the number average molecular weight of the linear molecule of the polyrotaxane compound (B) is preferably 300,000 or less, more preferably 200,000 or less, and 100,000 or less. More preferable.

  The block group of the polyrotaxane compound (B) is not particularly limited as long as it is a group capable of retaining a form in which a cyclic molecule is in a skewered state by a linear molecule. Such groups include bulky groups, ionic groups and the like.

  Specifically, the block group of the polyrotaxane compound (B) is a dinitrophenyl group, cyclodextrin, adamantane group, trityl group, fluorescein, pyrene, anthracene etc., or a number average molecular weight of 1,000 or more The main chain or side chain of a polymer of 1,000,000 or less is preferable, and two or more of these block groups may be mixed in the polyrotaxane compound (B) or in the pressure-sensitive adhesive composition.

  The weight average molecular weight of the polyrotaxane compound (B) is preferably 50,000 or more, and more preferably 100,000 or more. Moreover, one million or less is preferable and 800,000 or less is more preferable.

  The polyrotaxane compound (B) may be a synthetic product or a commercially available product. Examples of the synthesis method include the methods described in JP-A-2005-154675.

  Examples of commercially available products include, for example, SH1310P, SH2400P, and SH3400P (all manufactured by Advanced Soft Materials Co., Ltd.).

  The lower limit of the content of the polyrotaxane compound (B) in the pressure-sensitive adhesive composition for an optical film of the present invention is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the copolymer (A), It is more preferable that it is 0.1 mass part or more, and it is further more preferable that it is 0.3 mass part or more. When the content of the polyrotaxane compound (B) is 0.01 parts by mass or more, stress relaxation can be imparted to the pressure-sensitive adhesive layer by the effect of the polyrotaxane structure. The upper limit of the content of the polyrotaxane compound (B) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and still more preferably 3 parts by mass or less. When the content of the polyrotaxane compound (B) is less than or equal to the above upper limit value, the compatibility with the copolymer (A) can be favorably maintained, and an appropriate crosslinked structure can be imparted to the pressure-sensitive adhesive layer. .

<Crosslinking agent (C)>
The pressure-sensitive adhesive composition for an optical film of the present invention contains a crosslinking agent (C) as an essential component. The crosslinking agent (C) reacts with the (meth) acrylate copolymer (A) and the polyrotaxane compound (B) to form a cross-linked structure, and therefore, in the pressure-sensitive adhesive composition for an optical film, the adhesiveness (adhesiveness) is mainly And durability.

  In the present invention, the crosslinking agent (C) includes at least one 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. preferable. Below, these various crosslinking agents are demonstrated.

[Isocyanate Crosslinker]
In the present invention, examples of isocyanate-based crosslinking agents suitably used include triallyl isocyanurate, dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6 -TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), Aromatic diisocyanates such as tetramethyl xylidene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI); hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate Aliphatic diisocyanates such as methyl ethyl ketone (TMHDI), lysine diisocyanate, norbornane diisocyanate methyl (NBDI); transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12- Alicyclic diisocyanates such as MDI (hydrogenated MDI); carbodiimide-modified diisocyanates of the above diisocyanates; or these isocyanurate-modified diisocyanates. An adduct of the above-mentioned isocyanate compound with a polyol compound such as trimethylolpropane and a biuret or isocyanurate of these isocyanate compounds can also be suitably used.

  As these isocyanate crosslinking agents, synthetic products may be used, or commercially available products may be used.

  Commercially available products include, for example, Coronate (registered trademark) L, Coronate (registered trademark) HL, Coronate (registered trademark) HX, Coronate (registered trademark) 2030, Coronate (registered trademark) 2031 (all manufactured by Nippon Polyurethane Industry Co., Ltd.) ), Takenate (registered trademark) D-102, Takenate (registered trademark) D-110N, Takenate (registered trademark) D-200, Takenate (registered trademark) D-202 (all manufactured by Mitsui Chemicals, Inc.), Duranate (registered trademark) Trademarks 24A-100, Duranate (R) TPA-100, Duranate (R) TKA-100, Duranate (R) P301-75E, Duranate (R) E402-90T, Duranate (R) E405-80T , Duranate (registered trademark) TSE-100, Nate (registered trademark) D-101, Duranate (registered trademark) D-201 (all, Asahi Kasei Chemicals Corporation), Sumidur (registered trademark) N-75, N-3200, N-3300 (all, Sumika Bayer Co., Ltd.) Urethane Co., Ltd. etc. are mentioned. Among these, Coronate (registered trademark) L, Coronate (registered trademark) HL, Coronate (registered trademark) HX, Takenate (registered trademark) D-110N, Duranate (registered trademark) 24A-100, Duranate (registered trademark) TPA -100 are mentioned. Among them, Takenate (registered trademark) D-110N, Coronate (registered trademark) L, Coronate (registered trademark) HX, and Duranate (registered trademark) 24A-100 are preferable.

  Moreover, these isocyanate type crosslinking agents may be used in the form of an unblocked isocyanate compound, and may be used in the form of a blocked isocyanate compound obtained by reacting with a blocking agent that protects an isocyanate group. Good. Such a blocked isocyanate compound may be one obtained by synthesis or may be a commercially available product. Commercially available blocked isocyanate compounds are Duranate (registered trademark) MF-B60X (block 1,6-hexamethylene diisocyanate) manufactured by Asahi Kasei Chemicals Corporation, Duranate (registered trademark) MF-K60X (block 1,6-hexamethylene) Diisocyanate), Coronate (registered trademark) AP-M, 2503, 2507, 2513, 2515, manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate (registered trademark) MS-50, Takenate (registered trademark) B-830, manufactured by Mitsui Chemicals, Inc. (Block tolylene diisocyanate), B-815N (block 4,4'-methylenebis (cyclohexylisocyanate)), B-842N (block 1,3-bis (isocyanatomethyl) cyclohexane), B-846N (block 1) , -Bis (isocyanatomethyl) cyclohexane), B-874N (block isophorone diisocyanate), B-882N (block 1, 6-hexamethylene diisocyanate), Burnock manufactured by Dainippon Ink and Chemicals, Inc. (Registered trademark) D-500 (block tolylene diisocyanate), D-550 (block 1,6-hexamethylene diisocyanate), Elastron (registered trademark) BN-P17 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (Block 4,4'-diphenylmethane diisocyanate), BN-04, BN-08, BN-44, BN-45 (above, block urethane modified polyisocyanate) etc. are mentioned. Among these, Duranate (registered trademark) MF-K60X is particularly preferable.

  From the viewpoint of further improving the durability of the pressure-sensitive adhesive composition, the isocyanate-based crosslinking agent is preferably used in the form of an unblocked isocyanate compound.

  The isocyanate-based 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. By containing such an isocyanate compound, it is possible to exhibit a moderate crosslinking effect due to the long distance between the crosslinking points while suppressing the crowding of the crosslinked structure of the copolymer (A). By this, suppression of foaming as heating durability and suppression of peeling can be made to make compatible. From the viewpoint of further exhibiting such effects, the number average molecular weight (Mn) is preferably 900 or more and 7,000 or less, and more preferably 1,000 or more and 5,000 or less. In addition, the number average molecular weight (Mn) of an isocyanate type crosslinking agent can be calculated | required by the method similar to the measuring method of the weight average molecular weight of the copolymer (A) shown to an Example.

[Carbodiimide-based crosslinking agent]
In the present invention, the carbodiimide-based crosslinking agent is not particularly limited. For example, high molecular weight polycarbodiimide produced by decarboxylative condensation reaction of diisocyanate in the presence of a carbodiimide-forming catalyst is used.

  Examples of the diisocyanate to be subjected to the above decarboxylation condensation reaction include 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′- Diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, 3,3'-dimethyl-4,4'-diphenylether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4 -Diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethyl xylylene diisocyanate and the like.

  In addition, as a carbodiimidization catalyst used for the above decarboxylation condensation reaction, for example, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl- Examples include 2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, and phosphorene oxides such as 3-phospholene isomers thereof.

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

  Examples of commercially available products include Carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Co., Ltd. Among them, Carbodilite (registered trademark) V-01, V-03, V-05, V-07, and V-09 are preferable because they are excellent in compatibility with organic solvents.

[Oxazoline based crosslinking agent]
In the present invention, the oxazoline-based crosslinking agent is not particularly limited, but includes an oxazoline group-containing acrylic / styrene-based polymer having a main chain consisting of an acrylic skeleton or a styrene skeleton and having an oxazoline group in the side chain of the main chain. An oxazoline group-containing polymer such as an oxazoline group-containing acrylic polymer having a main chain composed of an acryl skeleton and having an oxazoline group in a side chain of the main chain is preferably used.

  As an oxazoline group, 2-oxazoline group, 3-oxazoline group, 4-oxazoline group etc. are mentioned, for example, Especially, 2-oxazoline group is preferable.

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

  Specific examples of oxazoline group-containing polymers include oxazoline group-containing acrylics such as Epocross (registered trademark) WS-300, Epocross (registered trademark) WS-500, and Epocross (registered trademark) WS-700 manufactured by Nippon Shokubai Co., Ltd. Examples include oxazoline group-containing acrylic / styrene-based polymers such as Epocross (registered trademark) K-1000 series and Epocross (registered trademark) K-2000 series manufactured by Nippon Shokubai Co., Ltd., and the like.

[Epoxy based crosslinking agent]
In the present invention, the epoxy-based crosslinking agent is not particularly limited, and a known epoxy-based crosslinking agent can be appropriately adopted. Examples of commercially available products include “TETRAD (registered trademark) -C” and “TETRAD (registered trademark) -X” manufactured by Mitsubishi Gas Chemical Co., Ltd., “Adecaresin (registered trademark) EPU series” manufactured by ADEKA Corporation and Examples thereof include liquid epoxy resins such as Adeka Resin (registered trademark) EPR series and "Celloxide (registered trademark)" manufactured by Daicel Corporation. These liquid epoxy resins are preferable in that they facilitate the mixing operation when producing the pressure-sensitive adhesive composition for an optical film.

[Aziridine crosslinker]
In the present invention, the aziridine-based crosslinking agent is not particularly limited, but a polyfunctional aziridine compound having a plurality of aziridine rings can be suitably used. As a polyfunctional aziridine compound, for example, U.S. Pat. No. 3,225,013, U.S. Pat. No. 4,490,505, and U.S. Pat. The compound etc. which were disclosed by the 104970 gazette are mentioned.

  Moreover, as a commercial item of an aziridine type crosslinking agent, Chemitite (registered trademark) PZ-33, Chemitite (registered trademark) DZ-22E etc. made by Nippon Shokubai Co., Ltd. are mentioned, for example.

  In the present invention, one type of crosslinking agent (C) may be used alone, or two or more types may be used in combination. When two or more types are combined, two or more types of crosslinking agents of the same type (for example, two types of isocyanate type crosslinking agents) may be combined, or one or more types of crosslinking agents of different types (for example, isocyanate type crosslinking) One agent and one carbodiimide type crosslinking agent may be combined.

  The content of the crosslinking agent (C) in the pressure-sensitive adhesive composition for an optical film of the present invention is not particularly limited, but is 0.001 parts by mass or more with respect to 100 parts by mass of the (meth) acrylate copolymer (A). The content is preferably 20 parts by mass or less, more preferably 0.01 parts by mass or more and 10 parts by mass or less, still more preferably 0.03 parts by mass or more and 5 parts by mass or less, 0.05 parts by mass or more It is particularly preferable that the amount is 3 parts by mass or less. A content of 0.001 parts by mass or more is preferable from the viewpoint of suppressing foaming at the time of heating durability. Moreover, it is preferable in the viewpoint that generation | occurrence | production of a dent can be suppressed. On the other hand, when the content is 20 parts by mass or less, it is preferable from the viewpoint of ensuring durability even in a severe environment without the cross-linked structure becoming too dense.

<Solvent (D)>
The pressure-sensitive adhesive composition for an optical film of the present invention contains a solvent (D). By including the solvent (D), a significant improvement effect of productivity at the time of coating can be obtained. The solvent (D) is not particularly limited, but 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; Alicyclic 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.

  Content of the solvent (D) in the adhesive composition for optical films of this invention is 80 mass% or less with respect to the total mass of the adhesive composition for optical films. When the content of the solvent exceeds 80% by mass, the productivity at the time of coating decreases, and the balance between the warpage and the generation of dents is reduced. The content of the 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 based on the total mass of the pressure-sensitive adhesive composition for an optical film, and is 50% by mass The content is more preferably 78% by mass or less and still more preferably 70% by mass or more and 77% by mass or less. If it is such a range of content, in addition to the remarkable improvement effect of durability and productivity at the time of coating, the balance of generation | occurrence | production suppression effect of curvature and a dent is especially excellent.

  Moreover, solid content content including the copolymer (A) in the adhesive composition for optical films of this invention is 20 mass% or more with respect to the total mass of the adhesive composition for optical films. When the solid content is less than 20% by mass, the productivity at the time of coating is reduced, and the balance between the warpage and the generation of dents is reduced. The solid content in the pressure-sensitive adhesive composition for an optical film is preferably 20% by mass or more and 70% by mass or less with respect to 100% by mass of the total amount of the pressure-sensitive adhesive composition for an optical film, and is 22% by mass or more The content is more preferably 50% by mass or less, and still more preferably 23% by mass or more and 30% by mass or less. Within such a content range, the balance of the warpage and dent generation suppressing effect is particularly excellent, the solid content at the time of coating is high, and the coating speed can be maintained at a higher level than before, and the manufacturing process It is possible to provide a pressure-sensitive adhesive composition for an optical film which can obtain a good quality adhesive type optical film having an excellent handling property in terms of surface.

  The solid content in 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 adjusting the amount of each component constituting the pressure-sensitive adhesive composition for an optical film. The solid content can be measured by removing non-solid components 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 adjusting the amount of each component constituting the pressure-sensitive adhesive composition for an optical film. The content of the solvent can be measured by volatilizing and drying the solvent from the pressure-sensitive adhesive composition for an optical film.

  Furthermore, the viscosity at 23 ° C. measured with a B-type viscometer (rotational speed 20 rpm) of the pressure-sensitive adhesive composition for an optical film of the present invention is 200 mPa · s or more and 5000 mPa · s or less. When the viscosity is less than 200 mPa · s or exceeds 5000 mPa · s, it is difficult to achieve both durability and reworkability, and the productivity at the time of coating decreases, and the warpage and occurrence of dents are suppressed. Balance 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, and particularly preferably 500 mPa · s or more and 3500 mPa · s or less. Within such a viscosity range, the durability and the reworkability are compatible, and in addition to the significant improvement effect of the productivity at the time of coating, the balance between the warpage and the nick generation suppression effect is particularly excellent.

  The viscosity at 23 ° C. measured with a B-type viscometer (rotational speed 20 rpm) of the pressure-sensitive adhesive composition for an optical film of the present invention is the molecular weight of the (meth) acrylate copolymer (A), solid content, thickener and the like Those skilled in the art can easily control the viscosity by appropriately adjusting the addition of additives capable of adjusting the viscosity. In the present specification, the viscosity at 23 ° C. measured by a B-type viscometer (rotational speed 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). In the pressure-sensitive adhesive composition for an optical film, the silane coupling agent (E) can contribute mainly to the improvement of the durability and the adhesion to the glass when the adherend is glass. In the present specification, the "silane coupling agent" means a silane compound having no 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 specifically, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, methyltrimethoxysilane, dimethyldimethoxymethane Silane, trimethylmethoxysilane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, n-butyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyl Dimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexene Sil) ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacrylic acid Roxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane , -Phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis- (3- [triethoxysilyl] propyl) tetrasulfide, γ-isocyanatopropyltriethoxysilane and the like can be mentioned. Furthermore, a silane cup containing a silane coupling agent having a functional group such as an epoxy group (glycidoxy group), an amino group, a mercapto group and a (meth) acryloyl group, and a functional group having reactivity with these functional groups. It is also possible to use a compound having a hydrolyzable silyl group obtained by reacting a ring agent, another coupling agent, polyisocyanate or the like in an arbitrary ratio with respect to each functional group.

  The silane coupling agent (E) may be a synthetic product or a commercially available product. As a commercial item of the silane coupling agent (E), for example, KBM-303, KBM-403, KBE-402, KBE-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802. , KBM-803, KBE-846, KBE-9007 (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

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

  The content of the silane coupling agent (E) in the case where the pressure-sensitive adhesive composition for an optical film of the present invention contains a silane coupling agent (E) is not particularly limited, but 100 parts by mass of the copolymer (A) The amount is preferably 0.001 parts by mass to 10 parts by mass, more preferably 0.005 parts by mass to 5 parts by mass, and still more preferably 0.01 parts by mass to 3 parts by mass. Particularly preferably, it is 0.01 parts by mass or more and 1 part by mass or less. A content of 0.001 parts by mass or more is preferable from the viewpoint that the effect on the durability can be exhibited even under a severe environment. On the other hand, it is preferable in the viewpoint that the deterioration of the heating foaming originating in a low molecular weight compound will be eliminated as content is 10 mass parts or less.

<Silicate oligomer (F)>
The pressure-sensitive adhesive composition for an optical film of the present invention preferably further comprises a silicate oligomer (F). A silicate oligomer (F) can mainly contribute to the improvement of rework property in the adhesive composition for optical films.

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

In the above chemical formula (1), R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group. Each of X ¹ and X ² independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a phenyl group. n is an integer of 1 or more and 100 or less, preferably 2 or more and 100 or less. Such alkyl groups and phenyl groups may be substituted or unsubstituted. In addition, the alkyl group may have a linear structure or a branched structure.

In the present invention, from the viewpoint of compatibility between durability and reworkability, among the compounds represented by the above chemical formula (1), all of R ¹ and R ² and X ¹ and X ² are methyl groups, methyl It is preferably a silicate oligomer. The silicate oligomer (F) may be used alone 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, and still more preferably 600 or more and 5000 or less. Preferably they are 600 or more and 5000 or less. When the weight average molecular weight is 300 or more, it is preferable from the viewpoint of easily securing reworkability. On the other hand, it is preferable in the viewpoint that it is easy to ensure durability that it is 30000 or less. 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) shown in the examples.

  Although the content in particular of a silicate oligomer (F) in case the adhesive composition for optical films of this invention contains a silicate oligomer (F) is not restrict | limited, Preferably with respect to 100 mass parts of copolymers (A), Is 0.01 to 50 parts by mass, more preferably 0.3 to 10 parts by mass, and still more preferably 0.5 to 5 parts by mass. A content of 0.01 parts by mass or more is preferable in that the effect on the durability is exhibited even under a severe environment. On the other hand, it is preferable at the point which rework property and durability make it compatible easily that content is 50 mass parts or less.

<Peroxide (G)>
The pressure-sensitive adhesive composition for an optical film of the present invention may further contain a peroxide (G). In the present specification, “peroxide” means a compound having a peroxide structure “—O—O—” in its molecular structure.

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

  The peroxide (G) according to the present invention is not particularly limited, and known ones can be used. In addition, as the peroxide (G), in consideration of productivity and stability, those having a half-life temperature of 80 ° C. or more and 160 ° C. or less are preferable, and those having 80 ° C. or more and 140 ° C. or less are more preferable. The temperature is preferably 80 ° C. or more and 125 ° C. or less, and more preferably 90 ° C. or more and 125 ° C. or less. The “peroxide half-life” is an index representing the decomposition rate of peroxide, and means the time until the remaining amount of peroxide is halved. The decomposition temperature for obtaining a half life in a certain time and the half life time at a certain temperature are described in the manufacturer catalog etc., for example, organic peroxide catalog 9th edition (2003) published by NOF Corporation Year of May).

  Examples of such peroxides (G) include, for example, diisopropyl peroxy dicarbonate (half-life temperature of 1 minute 88.3 ° C., hereinafter, the temperature in the parentheses indicates half-life temperature of 1 minute), di (di- 2-ethylhexyl) peroxydicarbonate (90.6 ° C), di (4-t-butylcyclohexyl) peroxydicarbonate (92.1 ° C), di-sec-butylperoxydicarbonate (92.4 ° C) , T-butylperoxy neodecanoate (103.5 ° C), t-hexylperoxypivalate (109.1 ° C), t-butylperoxypivalate (110.3 ° C), dilauroyl peroxide (116.4 ° C.), bis-n-octanoyl peroxide (117.4 ° C.), 1,1,3,3-tetramethylbutylperoxy-2-ethyl hexame Ate (124.3 ° C), di (4-methylbenzoyl) peroxide (128.2 ° C), dibenzoyl peroxide (benzoyl peroxide) (130.0 ° C), dibenzoyl peroxide and benzoyl m-methylbenzoylperone A mixture of oxide and m-toluoyl peroxide (131.1 ° C.), t-butyl peroxybutyrate (136.1 ° C.) and the like can be mentioned. Among them, diisopropyl peroxy dicarbonate, di (4-t-butylcyclohexyl) peroxy dicarbonate, and t-butyl peroxy neodecanoate are preferably used. These may be used alone or in combination of two or more from the viewpoint of controlling the reactivity. A combination of di (4-t-butylcyclohexyl) peroxydicarbonate and dilauroyl peroxide is preferred as an example in which two or more are used in combination.

  The peroxide (G) may be a synthetic product or a commercially available product.

  Commercially available products include, for example, trade names made by NOF Corporation: “Paroyl (registered trademark, the same as the following) IB” (85.1 ° C.), “Parkyl (registered trademark, the same as the following) ND (94.0 ° C.) ), “Peroyl NPP” (94.0 ° C.), “Peroyl IPP” (88.3 ° C.), “Perroyl SBP” (92.4 ° C.), “Perocta (registered trademark), the same as the following) ND” (92.4) ° C), “Peroyl TCP” (92.1 ° C.), “Peroyl OPP” (90.6 ° C.), “Perhexyl (registered trademark, hereinafter the same) ND” (100.9 ° C.), “Perbutyl (registered trademark, below) Same) ND "(103.5 ° C)," perbutyl NHP "(104.6 ° C)," perhexyl PV "(109.1 ° C)," perbutyl PV "(110.3 ° C)," peroyl 355 "(112) .6 ° C), " C.-Royl L "(116.4 ° C.)," Perocta O "(124.3 ° C.)," Perroyl SA "(131.8 ° C.)," Perhexa (registered trademark, the same as the following) 25 O "(118.8 ° C.), “Perhexyl O” (132.6 ° C.), “Nyper (registered trademark, same below) PMB” (128.2 ° C.), “Perbutyl O” (134.0 ° C.), “Nyper BMT” (131.1 ° C.) , "Nyper BW" (130.0 ° C), "Nyper BMT-K40" (131.1 ° C), "Nyper BMT-M" (131.1 ° C), "Perhexa MC" (142.1 ° C), " Perhexa TMH "(147.1 ° C)," Perhexa HC "(149.2 ° C)," Perhexa C "(153.8 ° C)," Pertetra (registered trademark, hereinafter the same) A "(153.8 ° C), "Perhexyl I" (1 5.0 ° C.), “Perbutyl L” (159.4 ° C.), “Perbutyl I” (158.8 ° C.), “Per Hexa 25 Z” (158.2 ° C.), “Perbutyl A” (159.9 ° C.), “Perhexa 22” (159.9 ° C.) and the like can be mentioned.

  In the present invention, the content of the peroxide (G) is preferably more than 0.05 parts by mass and 10 parts by mass or less with respect to 100 parts by mass of the (meth) acrylate copolymer (A). Within such a range, the heating durability at high temperature can be improved, and the crosslinking density becomes appropriate, and the durability and the stability of the pressure-sensitive adhesive composition are improved.

  In addition, from the viewpoint of further satisfying the heating durability at high temperature, the content of the peroxide (G) is 0.1 parts by mass with respect to 100 parts by mass of the (meth) acrylate copolymer (A). It is preferably more than 5.0 parts by mass or less, and more preferably more than 0.2 parts by mass and 3.0 parts by mass or less.

<High softening point resin (H)>
The pressure-sensitive adhesive composition for an optical film of the present invention further contains a high softening point resin (H) having a softening point of 60 ° C. or more and 200 ° C. or less (hereinafter, also simply referred to as “high softening point resin (H)”) Is preferred. By adding the high softening point resin (H), it is possible to provide a pressure-sensitive adhesive composition which has a characteristic that it is hard to some extent at room temperature and softens (makes soft) at high temperature. By adding the above-mentioned high softening point resin (H) and imparting such characteristics, the resin can be hardened at room temperature to effectively suppress the occurrence of dents. In addition, by softening at high temperature, stress relaxation can be provided in a high temperature (for example, 85 ° C.) environment, which is preferable in that generation of warpage can be effectively suppressed.

  The high softening point resin (H) used in the present invention is not particularly limited as long as it has a softening point of 60 ° C. or more and 200 ° C. or less from the viewpoint that the above-described effects can be effectively exhibited. Any of the conventionally known ones can be used. Specific examples thereof include, for example, aliphatic petroleum resins, alicyclic hydrocarbon resins, aromatic petroleum resins, fully hydrogenated aliphatic petroleum resins, fully hydrogenated alicyclic hydrocarbon resins, Petroleum resins such as fully hydrogenated aromatic petroleum resin, partially hydrogenated aliphatic petroleum resin, partially hydrogenated alicyclic hydrocarbon resin, partially hydrogenated aromatic petroleum resin, aromatic hydrocarbon resin, aliphatic Rosin-based resins (both rosins or rosin derivatives such as saturated hydrocarbon resins, terpene resins, terpene phenol resins, hydrogenated terpene resins, coumarone-indene resins, rosin acids, polymerized rosin acids and rosin ester resins (rosin acid esters) Preferred are epoxy resins, phenolic resins, oil-soluble phenols (resins), and modified resins thereof. One of these high softening point resins (H) may be used alone, or two or more thereof may be used in combination. Among these, from the viewpoint of good compatibility with the copolymer (A), alicyclic hydrocarbon resins, terpene phenol resins and terpene resins are more preferable. In addition, the high softening point resin (H) is a rosin ester resin from the viewpoint that the compatibility with other components of the pressure-sensitive adhesive composition is very good and transparency is easily obtained when applied to an optical film. It is further preferred that

  The high softening point resin (H) may be a synthetic product or a commercially available product.

  Examples of commercially available products of rosin ester resins include, for example, Pine Crystal (registered trademark, the same as the following) KR-85 (softening point 80-87 ° C., hereinafter the temperature in parentheses shows the softening point), Pine Crystal KR- 612 (80-90 ° C.), Pine Crystal KR-614 (84-94 ° C.), Pine Crystal KE-100 (95-105 ° C.), Pine Crystal KE-311 (90-100 ° C.), Pine Crystal PE-590 ( 90-100 ° C.), pine crystal KE-359 (94-104 ° C.), pine crystal KE-604 (124-134 ° C.), pine crystal KR-120 (110-130 ° C.), pine crystal KR-140 (130- 150 ° C.), Pine Crystal KR-614 (84-94 ° C.), Pine Crystal D-6011 ( 4-99 ℃), Pine Crystal KR-50M (145-160 ℃) (or higher, manufactured by Arakawa Chemical Industries, Ltd.), and the like. They are suitably used as ultra-light rosin in optical applications where transparency is required.

  Moreover, as another example of the commercial item of rosin ester resin, super ester A-75 (70-80 degreeC), super ester A-100 (95-105 degreeC), super ester A-115 (108-120 degreeC) And Super Ester A-125 (120-130 ° C.) (all manufactured by Arakawa Chemical Industry Co., Ltd.) and the like.

  Examples of commercially available products of alicyclic hydrocarbon resins include, for example, Alcon (registered trademark, the same below) P-90 (85-95 ° C), Alcon P-100 (95-105 ° C), Alcon (registered trademark) ) P-115 (110-120 ° C), Alcon P-125 (120-130 ° C), Alcon P-140 (135-145 ° C), Alcon M-90 (85-95 ° C), Alcon M-100 (95) -105 ° C.), Alcon M-115 (110-120 ° C.), Alcon M-135 (130-140 ° C.) (all manufactured by Arakawa Chemical Industries, Ltd.), and the like.

  As an example of the commercial item of terpene phenol resin, for example, Tamanor (registered trademark, the same in the following) 803L (145-160 ° C), Tamanor 901 (125-135 ° C) (above, Arakawa Chemical Industries Co., Ltd. make), YS polystar U130 (125-135 ° C), YS Polystar U115 (110-120 ° C), YS Polystar T160 (155-165 ° C), YS Polystar T145 (140-150 ° C), YS Polystar T130 (125) -135 ° C), YS polystar T115 (110-120 ° C), YS polystar T100 (95-105 ° C), YS polystar T80 (75-85 ° C), YS polystar S145 (140-150 ° C), YS polystar G150 (145) -155 ° C), YS Polystar G125 (120- 30 ° C.), YS Polystar N125 (120-130 ° C.), YS Polyster K125 (120-130 ° C.), YS Polyster TH130 (125-135 ℃) (or higher include Yasuhara Chemical Co., Ltd.).

  Examples of commercially available products of terpene resins include, for example, YS resin (registered trademark, the same as the following) PX1250 (120-130 ° C), YS resin PX1150 (110-120 ° C), YS resin PX1000 (95-105 ° C), YS Resin PX800 (75-85 ° C), YS resin PX1150N (110-120 ° C), YS resin TO125 (120-130 ° C), YS resin TO115 (110-120 ° C), YS resin TO105 (100-110 ° C), YS Resin TO 85 (80-90 ° C.) (all manufactured by Yasuhara Chemical Co., Ltd.) and the like.

  The addition amount of the high softening point resin (H) in the case of adding the high softening point resin (H) to the pressure-sensitive adhesive composition for an optical film of the present invention is not particularly limited, but a (meth) acrylate copolymer (A) 0.1 parts by weight or more and 30 parts by weight or less, preferably 0.5 parts by weight or more and 25 parts by weight or less, and more preferably 1 parts by weight or more and 20 parts by weight or less The content is more preferably 2 parts by mass or more and 15 parts by mass or less. When the content is 0.1 parts by mass or more, it is preferable from the viewpoint that the effect of the softening is obtained at the time of the durability test. Moreover, it is preferable in the viewpoint that generation | occurrence | production of curvature can be suppressed. On the other hand, it is preferable in the viewpoint that the deterioration of durability by a low molecular weight thing can be suppressed as content is 30 mass parts or less. Moreover, it is preferable in the viewpoint that durability can be ensured also in a severe environment, such as a flexibility fall of an adhesive constituent can be effectively suppressed also in a low temperature field like -25 ° C or less.

  The softening point of the high softening point resin (H) is preferably 60 ° C. or more and 200 ° C. or less, and further, heat resistance, tackiness, flexibility in a low temperature region such as −25 ° C. or less, durability and reworkability In view of the improvement of the above and the suppression of the occurrence of warpage and dents, it is more preferably 70.degree. C. or more and 150.degree. C. or less, still more preferably 80.degree. In the present invention, as the softening point, a value measured by the method described in JIS K 6863 (1994) is adopted.

<Other additive components>
The pressure-sensitive adhesive composition for an optical film of the present invention may contain, if necessary, a crosslinking accelerator, an antiaging agent, a filler, a coloring agent (such as a pigment or a dye), an ultraviolet absorber, an antioxidant, a chain transfer agent, and a plastic You may contain well-known addition components (other addition components), such as an agent, a softener, surfactant, and an antistatic agent, in the range which does not impair the effect of this invention.

<Production (Preparation) Method of Pressure-Sensitive Adhesive Composition>
In the present invention, the pressure-sensitive adhesive composition for an optical film is not particularly limited, and, for example, a copolymer (A), a polyrotaxane compound (B), a crosslinking agent (C), and a solvent (D) are optionally included. The silane coupling agent (E), the silicate oligomer (F), and the other additives can be prepared by mixing. The order of mixing of the respective components, the mixing temperature, and the like are not particularly limited, and can be appropriately adjusted by those skilled in the art.

[Use]
The pressure-sensitive adhesive composition for an optical film of the present invention described above is suitable for various uses. For example, it is preferably used for optical members, such as an optical film. In particular, in recent years, it is preferably used for a thin adhesive type optical film used for a large liquid crystal panel. As such an optical film, a polarizing plate, a retardation plate for preventing coloring, an optical compensation film such as a viewing angle widening film for improving the viewing angle of a liquid crystal display, a brightness improving film for enhancing the contrast of the display, Furthermore, the thing in which these are laminated | stacked is mentioned.

  In the present invention, the form of a pressure-sensitive adhesive layer formed of the above-described pressure-sensitive adhesive composition for an optical film, the form of an optical member having the pressure-sensitive adhesive layer formed on an optical film, etc., the optical film is a polarizing plate A mode or a mode in which the optical member is applied to a liquid crystal display, an organic EL display, a plasma display (PDP), a micro LED display, an image display such as a curved display or a flexible display, or the like may be provided. Each of these will be described below.

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

  The thickness (film thickness after drying) of the pressure-sensitive adhesive layer of the present invention can be appropriately set by those skilled in the art according to the application, but is preferably 1 μm to 200 μm, more preferably 3 μm to 75 μm, More preferably, it is 5 μm or more and 40 μm or less, particularly preferably 7 μm or more and 35 μm or less, and most preferably 10 μm or more and 30 μm or less. It is preferable from the viewpoint that the durability and the adhesive property can be well balanced if the thickness is in the above range.

  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 punching and slitting. Moreover, it is preferable that it is 40% or more, and it is more preferable that it is 65% or more from a viewpoint which there is no concern to the dent and curvature to the adhesive layer immediately after drying, curvature, or durability, and requiring an aging process. The gel fraction can be adjusted by controlling the amount of crosslinking agent and the amount of peroxide.

[Method of producing pressure-sensitive adhesive layer]
According to another aspect of the present invention, a pressure-sensitive adhesive composition for an optical film, which comprises applying the above-described pressure-sensitive adhesive composition for an optical film of the present invention onto a release-treated release sheet and then heat treatment to cause a crosslinking reaction. Methods of making the agent layer are also provided.

  When the pressure-sensitive adhesive composition is used for an optical film, the pressure-sensitive adhesive composition may be coated directly on the optical film to form a pressure-sensitive adhesive layer, but the pressure-sensitive adhesive composition may be formed on a film having releasability. It is desirable to apply an object to form a pressure-sensitive adhesive layer and then transfer it to various optical films for use. Also, the film having releasability with a pressure-sensitive adhesive layer thus produced can be rolled up together in the production process to form a roll, and it may be cut or processed as necessary to obtain various films. When sticking to an optical film, a liquid crystal panel, etc., the film which has the said mold release property can be removed and used. Furthermore, the film having releasability can also play a role of protecting the pressure-sensitive adhesive layer until the pressure-sensitive adhesive layer is put to practical use. In the present specification, a film having such releasability is also referred to as a release sheet (separator).

  As a constituent material of the release sheet, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, polyester film, porous materials such as paper, cloth, non-woven fabric, nets, foamed sheets, metal foils, laminates thereof, etc. And the like, but a plastic film is preferably used from the viewpoint of excellent surface smoothness.

  The thickness of the release sheet is usually 5 μm or more and 200 μm or less, preferably about 5 μm or more and 100 μm or less.

  The release sheet may be, if necessary, a release agent of silicone type, fluorine type, long chain alkyl type or fatty acid amide type, release treatment with silica powder, antifouling treatment, coating type, kneading type, vapor deposition It is possible to further perform an antistatic treatment such as a mold. In particular, from the viewpoint of being able to further enhance the releasability from the pressure-sensitive adhesive layer, the surface of the release sheet is preferably subjected to release treatment such as silicone treatment, long chain alkyl treatment, fluorine treatment and the like.

  In the present invention, the method of applying the pressure-sensitive adhesive composition for an optical film of the present invention on a release sheet subjected to release treatment is not particularly limited, and various known methods may be used. 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, lip coating, die coater, etc. The method is mentioned.

  In the manufacturing method of the adhesive layer of this invention, the process of heat-processing after apply | coating the adhesive composition for optical films mentioned above on a release sheet is performed. The heat treatment step concerned not only dries and removes the solvent in the coating film obtained by coating, but also serves the purpose of causing the above-mentioned pressure-sensitive adhesive composition for an optical film to undergo a crosslinking reaction. The temperature of the heat treatment is preferably 40 ° C. or more and 150 ° C. or less, more preferably 50 ° C. or more and 130 ° C. or less, and still more preferably 80 ° C. or more and 120 ° C. or less. By setting the temperature of the heat treatment in the above range, a pressure-sensitive adhesive layer having excellent adhesion properties can be obtained.

  The heat treatment time may be set as appropriate, but is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and still more preferably 10 seconds to 5 minutes, particularly Preferably, it is 10 seconds or more and 2 minutes or less.

  Further, the means for the heat treatment is not particularly limited, and various known methods may be used. For example, a parallel drying method in which the hot air is blown in the same direction as the film transport direction, a counter drying method in which the hot air is blown in the film transport direction in the different direction, a float drying method in which the hot air is blown directly from above and below the film The method is mentioned.

[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 provided on one surface of the pressure-sensitive adhesive layer.

  The optical member of the present invention may further have glass or a second optical film on the surface of the pressure-sensitive adhesive layer of the present invention opposite to the surface provided with the first optical film. Here, the “first optical film” and the “second optical film” may be films having the same configuration (material, function, etc.), and different structures (material, function, etc.) It may be a film having one. In the present invention, there is also provided a form in which the first optical film (or the second optical film) is a polarizing plate.

  In the present invention, the pressure-sensitive adhesive composition described above may be used by directly applying it to one side or both sides of an optical film to form a pressure-sensitive adhesive layer, but for the reasons described above It is desirable to use by forming and transferring this to one or both sides of the optical film. Before transfer, depending on the material of the surface of the optical film, surface treatment such as formation of an adhesion promoting layer or formation of an antistatic layer may be performed. Moreover, you may perform an easily adhesive process also on the surface of an adhesive layer. From the viewpoint of firmly bonding the optical film and the pressure-sensitive adhesive layer, it is preferable to have an easy-adhesive treatment layer between the optical film and the pressure-sensitive adhesive layer for an optical film of the present invention.

<Easy adhesion treatment layer (Easy adhesion layer)>
The optical member of the present invention preferably further comprises at least one easy-adhesion treatment layer between the first optical film and the pressure-sensitive adhesive layer for an optical film.

  Moreover, as a more preferable form, the optical member of this invention has a 1st easily-adhesive-treated layer in the surface of the side facing the said adhesive film layer for optical films of the said 1st optical film, The said optical film A second easy-adhesion treatment layer is provided on the side of the pressure-sensitive adhesive layer facing the first optical film. As described above, in the optical member, the configuration having both the first and second easily adhesion-treated layers is preferable from the viewpoint that the optical film and the pressure-sensitive adhesive layer can be more firmly adhered.

  The easy-adhesion treatment layer may treat the surface of a member in contact with the pressure-sensitive adhesive layer, such as corona treatment or plasma treatment, or a member in which a separate member such as a primer layer is in contact with the pressure-sensitive adhesive layer It may be provided on the surface of

  The material which comprises a primer layer has favorable adhesiveness with the member which contacts a primer layer, and what forms the film | membrane which is excellent in cohesive force is preferable. For example, various polymers, sols of metal oxides, silica sols and the like are used, and among them, polymers are 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 an amino group in the molecule. Among these, polyurethane resins and oxazoline group-containing polymers are more preferably used.

  A commercially available product can be used as the oxazoline group-containing polymer. Examples thereof include, but are not limited to, Epocross (registered trademark) series (for example, Epocross (registered trademark) WS700) manufactured by Nippon Shokubai Co., Ltd., and the like. Moreover, about polyurethane resin, polyester resin, polymers which contain an amino group in a molecule | numerator, what is disclosed by stage "0107"-"0113" of Unexamined-Japanese-Patent No. 2011-105918 may be employ | adopted suitably.

  The thickness of the primer layer is preferably 10 nm or more and 5000 nm or less, more preferably 50 nm or more and 500 nm or less. Within the above range, optical characteristics 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 applying the raw material (primer) of the primer layer using a coating method such as a coating method, dipping method, spray method and the like and drying it. .

<Optical film>
In the present invention, an optical film (a first optical film or a second optical film) includes a polarizing plate, a retardation plate for preventing coloring, a viewing angle widening film for improving the viewing angle of a liquid crystal display, etc. Examples include, but are not limited to, a compensation film, a brightness enhancement film for enhancing the contrast of a display, and a laminate of these.

<Polarizer>
In the present invention, a polarizing plate suitable as an optical film is manufactured by bonding a protective film and a polarizer with an adhesive and curing by heat drying, ultraviolet light, electron beam or the like by a conventionally known method. obtain. The applied adhesive develops adhesion by drying or curing with ultraviolet light, electron beam or the like to form an adhesive layer.

  There is no restriction | limiting in particular as a polarizer, A conventionally well-known thing can be used. For example, a dichroic material such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene / vinyl acetate copolymer-based partially saponified film. Polyene-based oriented films such as those uniaxially stretched, dewatered products of polyvinyl alcohol, dehydrochlorinated products of polyvinyl chloride, and the like.

  Among them, a polarizer produced by dyeing 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 uniaxially stretching 3 to 8 times is particularly preferable. . More specifically, such a polarizer is obtained, for example, by immersing a polyvinyl alcohol film in an aqueous solution of iodine, dyeing, and stretching.

  As a method of immersing in an aqueous solution of iodine, for example, it is preferable to immerse in an aqueous solution containing 0.1% by mass or more and 10% by mass or less of iodine and / or potassium iodide. Further, if necessary, it may be immersed in an aqueous solution of boric acid or potassium iodide at 50 ° C. or more and 70 ° C. or less, and it may be immersed in water at 25 ° C. or more and 35 ° C. or less to prevent washing and dyeing unevenness. It is also good. Stretching may be carried out after staining with iodine, stretching while staining, or may be stretched and then dyed 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 about 1 minute or more and 10 minutes or less. A wide variety of such polarizers are commercially available.

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

  In the present invention, from the viewpoint that higher durability is required as the optical film, a polarizing plate in which one side or both sides are protected as the optical film is preferable. It does not restrict | limit especially as a method of protection, Well-known methods, such as bonding a protective film, may be employ | adopted suitably.

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

  A transparent protective film is attached to one side of the polarizer with an adhesive, but the other side is a transparent protective film, or as a protective layer, (meth) acrylic, urethane, acrylic urethane, epoxy, A thermosetting resin such as silicone or an ultraviolet curable resin can be used.

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

  The manufacturing method of a polarizing plate is not specifically limited, For example, after apply | coating an adhesive agent, it can carry out by bonding a polarizer and a protective film together by a roll laminator etc. After bonding, a curing process may be performed by drying, ultraviolet light, electron beam or the like as appropriate. Moreover, when apply | coating an adhesive agent, you may apply | coat to any of a protective film and a polarizer, and you may apply | coat to both. The adhesive is preferably applied so that the thickness of the adhesive layer after drying is 10 nm or more and 10 μm or less. Moreover, it does not specifically limit as an adhesive agent, According to the material of a polarizer, it can employ | adopt suitably from a well-known thing. For example, when using a polyvinyl-alcohol-type film as a polarizer, an acryl type, an epoxy type, an acryl- epoxy type can be used as a polyvinyl alcohol-type adhesive agent or an ultraviolet curing adhesive. The thickness of the adhesive layer is preferably 10 nm or more and 200 nm or less for a polyvinyl alcohol-based adhesive, and 0 for a UV-curable adhesive, in order to obtain a uniform in-plane thickness and sufficient adhesive strength. It is preferable that the thickness is from 2 μm to 10 μm.

  In the present invention, a pressure-sensitive adhesive polarizing plate on which a pressure-sensitive adhesive layer is formed can also be provided. In addition, about the structure of an adhesion type polarizing plate, manufacture, etc., since it is the same as that of the case of the optical film which has the adhesive layer mentioned above, description is abbreviate | omitted here.

[Image display device]
The present invention also provides an image display device 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 plasma display (PDP), a micro LED display, and the like. In addition, a thin image display device is preferably applied from the viewpoint of exhibiting the effects of the pressure-sensitive adhesive composition of the present invention more remarkably.

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

  In the following operations, unless otherwise specified, measurements of operations and physical properties are performed under the conditions of 23 ° C. and relative humidity 55% RH.

(Measurement of Weight Average Molecular Weight (Mw) of Copolymer (A))
The weight average molecular weight of each (meth) acrylate copolymer (A) prepared in the following production examples was measured by gel permeation chromatography (GPC) (see the measurement conditions below).
-Analyzer: Tosoh Co., Ltd. HLC-8120 GPC
・ Column: Tosoh Co., Ltd., G7000HXL + GMHXL + GMHXL
・ Column size: Each 7.8mmφ × 30cm in total 90cm
・ Column temperature: 40 ° C
・ Flow rate: 0.8 ml / min
Injection volume: 100 μl
Eluent: Tetrahydrofuran Detector: Differential Refractometer (RI)
Standard sample: polystyrene.

(Measurement of Weight Average Molecular Weight (Mw) of Silicate Oligomer (F))
Moreover, the weight average molecular weight of the silicate oligomer (F) used in the following Example was measured by gel permeation chromatography (GPC) (the measurement conditions are as follows):
-Analyzer: Tosoh Co., Ltd. HLC-8120 GPC
・ Column: TSKgel Super HZM-H / HZ4000 / HZ2000
Column size: 6.0 mm I. D. × 150 mm
・ Column temperature: 40 ° C
・ Flow rate: 0.6 ml / min
Injection volume: 20 μl
Eluent: Tetrahydrofuran Detector: Differential Refractometer (RI)
Standard sample: polystyrene.

Preparation Example 1: Preparation of Solution of (Meth) Acrylate Copolymer (A1)
A 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet pipe, and a cooler, 99 parts by mass of n-butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) ) 1 part by mass and 0.1 parts by mass of 2,2'-azobisisobutyro nitrile (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator are charged together with 100 parts by mass of ethyl acetate, and gently stirred. While introducing nitrogen gas. After nitrogen gas substitution, the liquid temperature in the flask is raised until ethyl acetate refluxes, polymerization reaction is carried out for 5 hours, and a solution of (meth) acrylate copolymer (A1) having a weight average molecular weight (Mw) of 900,000. Was prepared.

Preparation Examples 2 to 11 Preparation of Solutions of (Meth) Acrylate Copolymers (A2) to (A11)
The same as in Production Example 1 except that the type of each monomer forming the (meth) acrylate copolymer and the composition ratio thereof are changed as shown in Table 1 below, and the amount of polymerization initiator and the reaction time are appropriately changed. An operation was carried out to prepare solutions of (meth) acrylate copolymers (A2) to (A11). The weight average molecular weights (Mw) of (meth) acrylate copolymers (A1) to (A8) and (A10) to (A11) are also shown in Table 1. The blank in Table 1 represents that the monomer was not used. The methacrylate copolymer (A9) could not be measured for weight average molecular weight because the solution gelled.

Example 1
[Preparation of Pressure-Sensitive Adhesive Composition for Optical Film]
Polyrotaxane compound (B) relative to 100% by mass of the solid content of the (meth) acrylate copolymer (A1) solution obtained in Production Example 1 (that is, 100 parts by mass of (meth) acrylate copolymer (A1)) As SH1310P (Advanced Soft Materials Co., Ltd., number average molecular weight of linear molecule (polyethylene glycol): 11,000, hydroxyl value of cyclic molecule: 85 mg KOH / g, weight average molecular weight of compound: 180,000) 2 Parts by mass, Takenate (registered trademark) D-110N as a crosslinking agent (C) (75 wt% ethyl acetate solution of trimethylolpropane adduct of xylylene diisocyanate, number of isocyanate groups in one molecule: 3, Mitsui Chemicals Co., Ltd.) 0.1 mass part (as an active ingredient conversion), and KBM-403 (3 as a silane coupling agent (E) Glycidoxypropyltrimethoxysilane, stirring and mixing the Shin-Etsu Chemical Co., Ltd.) 0.1 part by mass, an optical film pressure-sensitive adhesive composition (solid content 25 wt%) was prepared.

[Formation of adhesive layer]
The pressure-sensitive adhesive composition for an optical film obtained above is dried on one side of a 38 μm thick polyethylene terephthalate (PET) film (Mitsubishi Chemical Co., Ltd., MRF 38, no oligomer prevention layer) which has been treated with silicone. The pressure-sensitive adhesive layer was applied to a thickness of 20 μm and heat-treated at 110 ° C. for 2 minutes to form the pressure-sensitive adhesive layer of Example 1. The heat treatment was performed by a float drying method in which hot air was blown directly from above and below the film.

[Production of Optical Member]
(Production of double-sided protective polarizing plate)
A double-sided protective polarizing plate was produced as an optical film according to the following steps.

  A polyvinyl alcohol film having a thickness of 60 μm was stretched up to three times while being stained for 1 minute in a 0.3% by mass iodine solution at 30 ° C. between rolls with different speed ratios. Thereafter, the film stretched to 3 times is stretched until the total stretch ratio becomes 6 times while being immersed for 0.5 minutes in an aqueous solution containing 60% of 4% by weight of boric acid and 10% by weight of potassium iodide. did. Then, the film stretched to 6 times is washed by immersion for 10 seconds in an aqueous solution containing potassium iodide at 1.5% by mass at 30 ° C., and then dried at 50 ° C. for 4 minutes to obtain a polarizer. The On one side of the polarizer, a triacetylcellulose (TAC) film (protective film) with a thickness of 40 μm, and on the other side a PET film with a thickness of 80 μm (Cosmo Shine (registered trademark) Superbirefringence manufactured by Toyobo Co., Ltd.) A PET film of the type (SRF); a protective film) was bonded with a polyvinyl alcohol-based adhesive to prepare a thin polarizing plate (also referred to simply as a double-sided protective polarizing plate) having a total thickness of 143 μm.

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

Examples 2 to 26 and Comparative Examples 1 to 4
As shown in Table 2 below, the (meth) acrylate copolymer (A), the polyrotaxane compound (B), the crosslinking agent (C), and optionally the silane coupling that constitute the pressure-sensitive adhesive composition for an optical film It corresponds to Examples 2 to 26 and Comparative Examples 1 to 4 in the same manner as the operation of Example 1 except that the type and added amount (blending amount) of the agent (E) and the silicate oligomer (F) are changed. A double-sided protective polarizing plate with an adhesive layer was produced.

In Table 2 above,
1. The blending amount (parts by mass) of the components (B), (C), (E), (F), (G), (H) and (I) is 100 parts by mass of the (meth) acrylate copolymer (A). Indicates the blending amount in the case of part 2. "-" In a table | surface represents that the said component is not mix | blended. "SH2400P": Product manufactured by Advanced Soft Materials Co., Ltd. (number average molecular weight of linear molecule (polyethylene glycol): 20,000, hydroxyl value of cyclic molecule: 76 mg KOH / g, weight average molecular weight of compound: 400,000) 4. "SH3400P": Product manufactured by Advanced Soft Materials, Inc. (number-average molecular weight of linear molecule (polyethylene glycol): 35,000, hydroxyl value of cyclic molecule: 72 mg KOH / g, weight average molecular weight of compound: 70 10)). "Methyl silicate 53A": a product (trade name: methyl silicate 53A) manufactured by Colcoat Co., Ltd. "V-05": A carbodiimide type crosslinking agent, which is a product (Nisshinbo Chemical Co., Ltd.) (Carbodilite (registered trademark) V-05). “WS-500”: an oxazoline crosslinking agent, which is a product (Epocross (registered trademark) WS-500) manufactured by Nippon Shokubai Co., Ltd. "TETRAD-X": an epoxy-based crosslinking agent, a product manufactured by Mitsubishi Gas Chemical Co., Ltd. (TETRAD (registered trademark) -X, N, N, N ', N'-tetraglycidyl-m-xylene diamine) 9. "PZ-33": An aziridine-based cross-linking agent manufactured by Nippon Shokubai Co., Ltd. (Chemitite (registered trademark) PZ-33, 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate) 10. "Nyper BMT-K40": A product manufactured by NOF Corporation (benzoyl peroxide, active ingredient amount: 40% by mass, half-life temperature per minute: 131.1 ° C). The addition amount in Table 2 above is the addition amount converted to the amount of active ingredient. “Pine Crystal KE-100”: A commercial product manufactured by Arakawa Chemical Industries, Ltd. (softening point 95-105 ° C. (ring and ball method), ultra-light rosin derivative). "Alfon (registered trademark) UH-2170": a product manufactured by Toagosei Co., Ltd. (solventless styrene acrylic polymer, weight average molecular weight (Mw) 14,000, glass transition temperature (Tg) 60 ° C).

[Evaluation]
The following evaluations were performed on the pressure-sensitive adhesive compositions for optical films prepared in the above Examples 1 to 26 and Comparative Examples 1 to 4 and the double-sided protective polarizing plate (sample) with the pressure-sensitive adhesive layer as an optical member. The

<Coating solution solid content (solid content)
The pressure-sensitive adhesive composition for an optical film prepared in the above Examples 1 to 26 and Comparative Examples 1 to 4 is dried by heating at 150 ° C. for 30 minutes, and the volatilization residue at that time is “coating liquid solid content (mass%) ".

<Viscosity>
The pressure-sensitive adhesive compositions for optical films prepared in Examples 1 to 26 and Comparative Examples 1 to 4 are rotated at a rotation number of 20 rpm with a Brookfield viscometer (B-type viscometer), and one minute from the start The subsequent numerical values were read to obtain viscosity values.

<Warp>
The optical members (double-sided protective polarizing plates with pressure-sensitive adhesive layer) produced in Examples 1 to 26 and Comparative Examples 1 to 4 above were cut into a size of 100 mm long × 50 mm wide, and used as samples. This sample was stuck to a 75 mm long × 150 mm wide × 0.5 mm thick alkali-free glass (manufactured by Corning, Eagle XG) using a laminator. Then, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the non-acrylic glass. The samples subjected to such treatment were further subjected to heat treatment at 85 ° C. for 100 hours respectively, and then left to stand at 25 ° C. and relative humidity 55% RH for 1 hour, and the amount of warpage became convex. The plane was placed on the horizontal plane so that the bottom side was down, and the distance (mm) of the longest point from the horizontal plane was measured among the four points of the corner. The evaluation criteria are as follows:
-Evaluation criteria-
:: Warpage amount of 0 mm or more and less than 0.5 mm ○: Warpage amount of 0.5 mm or more and less than 1.0 mm Δ: Warpage amount of 1.0 mm or more and less than 1.5 mm ×: Warpage amount of 1.5 mm or more.

<Dentation mark>
Optical members (adhesive layer with adhesive layer immediately after coating (immediately after transfer of a PET film having an adhesive layer formed thereon; within 10 minutes after transfer) prepared in Examples 1 to 26 and Comparative Examples 1 to 4 above The polarizing plate was cut into a size of 100 × 100 mm to prepare a total of 300 sample pieces (samples). These sample pieces are stacked with the PET film (protective film) side of the polarizing plate (the protective film side on which the pressure-sensitive adhesive layer is not formed) face up, and a load of 1 kg is applied from above, 23 ° C., relative humidity It was left for 1 day under the condition of 50% RH, and the generation depth of the mark was evaluated by a laser microscope (VK-X120) manufactured by Keyence Corporation. The evaluation criteria are as follows:
-Evaluation criteria-
:: Depth of dent of 0 μm or more and less than 1 μm ○: Depth of dent of 1 μm or more and less than 3 μm Δ: Depth of dent of 3 μm or more and less than 5 μm x: Depth of dent of 5 μm or more

<Durability>
The optical members (double-sided protective polarizing plates with pressure-sensitive adhesive layer) prepared in Examples 1 to 26 and Comparative Examples 1 to 4 above are cut into 37-inch sizes and used as samples, which are 0.7 mm thick alkali-free glass (Corning Corp. (EAGLE XG) was attached using a laminator. Then, the sample was autoclaved at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the sample to the non-acrylic glass. The samples subjected to the treatment were subjected to the following durability tests (1) to (3), and after each test, the appearance between the polarizing plate and the glass was visually evaluated based on the following criteria:
(1) Treated at 85 ° C. for 500 hours (heating test)
(2) Treated under an atmosphere of 60 ° C./relative humidity 95% RH for 500 hours (humidification test)
(3) After leaving for 30 minutes in an environment of 85 ° C., leaving 30 minutes in an environment of −40 ° C. as one cycle (1 hour), for a total of 300 cycles (300 hours) processed (heat shock (HS) test .

Visual evaluation ◎: no change in appearance such as foaming, peeling, no floating at all ○: slight peeling at the end, or foaming, but practically no problem Δ: peeling at the end, or foaming If it is not a special application, there is no problem in practical use. ×: There is significant peeling at the end, and there is a problem in practical use.

Oligomer contamination
The pressure-sensitive adhesive compositions of Examples 1 to 26 and Comparative Examples 1 to 4 are applied to a polyethylene terephthalate (PET) film (thickness 38 μm, manufactured by Mitsubishi Chemical Corporation, MRF 38) without an oligomer prevention layer. The coating line was applied for 2 hours under the heat treatment temperature shown in Table 2. When heat treatment was carried out while transporting the film, it was visually observed whether or not the PET oligomer was deposited on the guide roll of the coating line, and evaluated according to the following criteria:
Evaluation criteria A: No PET oligomer precipitation on the guide roll Δ: Some amount of PET oligomer precipitation on the guide roll C: There is a large amount of PET oligomer precipitation on the guide roll.

<Light leak>
Each of the optical members produced in the above Examples 1 to 26 and Comparative Examples 1 to 4 was cut out as samples so that the upper and lower polarizing plates were orthogonal to each other in a size of 420 mm long and 320 mm wide. This sample was bonded by a laminator on both sides of a 0.7 mm thick alkali-free glass plate (manufactured by Corning, Eagle XG (registered trademark)) so as to be in a crossed nicol state. Then, autoclave treatment was carried out at 50 ° C. and 5 atm for 15 minutes to obtain a secondary sample (initial). Thereafter, the secondary sample was treated for 48 hours at 105 ° C. (after heating). The heated secondary samples were placed on a 10,000 candelas backlight and the light leakage was visually evaluated according to the following criteria:
Evaluation criteria ◎: There is no occurrence of corner unevenness and there is no problem for practical use ○: Although corner unevenness is slightly generated but does not appear in the display area, there is no problem for practical use Δ: Corner unevenness occurs and displayed Although it appears slightly in the area, there is no problem in practical use. X: Corner unevenness occurs and appears tightly in the display area, and there is a problem in practical use.

<Reworkability>
The optical members produced in Examples 1 to 26 and Comparative Examples 1 to 4 were cut into pieces 25 mm wide and 100 mm long, and cut into pieces 420 mm long and 320 mm wide sample 2 (3 sheets prepared) did. The sample 1 and the sample 2 are respectively adhered to a 0.7 mm thick alkali-free glass plate (manufactured by Corning, Eagle XG) using a laminator, and then autoclaved at 50 ° C., 5 atm for 15 minutes for complete Close contact (initial). Then, it heat-processed on the dry conditions of 50 degreeC for 48 hours (after heating).

  The adhesion of the sample 1 was measured. The adhesion is measured with a tensile tester (manufactured by ORIENTEC Co., Ltd., Tensilon Universal Material Tester, STA-1150) at a peeling angle of 180 ° and a peeling speed of 300 mm / min under conditions of 23 ° C. and relative humidity 50% RH. It asked by measuring adhesion (N / 25 mm) at the time of tearing off sample 1 based on a method of an adhesive tape of JIS Z 0237 (2009), and an adhesive sheet test.

Moreover, about the said sample 2 (three sheets), the sample was peeled off from the non-alkali glass board by human hands, and the rework property was evaluated by the following reference | standard (actual rework property):
Evaluation criteria ◎: All three sheets were free of adhesive residue and film breakage and could be peeled well ○: Some of the three sheets were broken film, but peeled off again due to peeling Δ: All three sheets were broken film, It peeled off by peeling again. X: The adhesive residue occurred with all three sheets, or the film was broken and could not be peeled even if it peeled again and again.

  Each evaluation result is shown in the following Table 3.

  As is apparent from Table 3 above, the double-sided protective polarizing plate with the pressure-sensitive adhesive layer using the pressure-sensitive adhesive composition for an optical film of the present invention of Examples 1 to 26 is under severe environment (high temperature, high humidity It was found that it was possible to achieve both of the durability and the reworkability in heat shock, and to suppress the occurrence of both warpage and dents. Specifically, the double-sided protective polarizing plate (Examples 1 to 26) with the pressure-sensitive adhesive layer as an optical member having the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition for an optical film of the present invention There was almost no peeling, floating or bubbling due to the adhesive in the durability test. In addition, it is possible to reduce the adhesive strength immediately after attaching the double-sided protective polarizing plate with the adhesive layer, which is an optical member, to an image display device, such as a liquid crystal cell of a large liquid crystal display device, thinner than before. There is no increase in adhesion to the liquid crystal cell even if a long time passes after passing through the process or storage at high temperature, and a double-sided protective polarizing plate with a pressure-sensitive adhesive layer as an optical member from the liquid crystal cell It was suggested that it could be easily peeled off. As a result, it was confirmed that the reworkability was excellent, and the liquid crystal cell etc. could be reused without damage or contamination. Also, conventionally, in liquid crystal cells and the like used in large image display devices, it has been difficult to suppress both the warpage of liquid crystal cells and the like and the dents of adhesive layer, but according to Examples 1 to 26, It was also confirmed that these characteristics can be satisfied at the same time. On the other hand, in the double-sided protective polarizing plate with the adhesive layer of Comparative Examples 1 to 4, it is difficult to achieve both durability and reworkability under severe environments (high temperature, high humidity, heat shock), and warp and dent It turned out that one can not be suppressed.

Claims (25)

(A1) Structural units derived from alkyl (meth) acrylate monomers, and structural units derived from (meth) acrylate monomers having 0.01 to 10% by mass of (a2) hydroxyl group with respect to 100% by mass of the total of the constituent units And at least one structural unit selected from the group consisting of a structural unit derived from a monomer having a carboxyl group of 0.01 to 7% by mass with respect to 100% by mass of the total amount of structural units,
(Meth) acrylate copolymer (A) containing
Polyrotaxane compound (B) having as a cyclic molecule a cyclic oligosaccharide having a hydroxyl group as a reactive group,
Crosslinking agent (C), and solvent (D),
A pressure-sensitive adhesive composition for an optical film comprising
The (meth) acrylate copolymer (A) has a weight average molecular weight of 300,000 to 1,200,000 or less by gel permeation chromatography (GPC),
The solid content of the (meth) acrylate copolymer (A) in the pressure-sensitive adhesive composition for an optical film is 20% by 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% by mass or less based on the total mass of the pressure-sensitive adhesive composition for an optical film,
The adhesive composition for optical films whose viscosity in 23 degreeC measured by B-type viscosity meter (rotation speed 20 rpm) of the said adhesive composition for optical films is 200 mPa * s or more and 5000 mPa * s or less.   The optical film according to claim 1, wherein the content of the polyrotaxane compound (B) is 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the (meth) acrylate copolymer (A). Adhesive composition.   The adhesive composition for optical films of Claim 1 or 2 in which the said (meth) acrylate copolymer (A) further contains the structural unit derived from the (a4) aromatic containing (meth) acrylate monomer.   The silane coupling agent (E) 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 relative to 100 parts by mass of the (meth) acrylate copolymer (A). The adhesive composition for optical films as described in-. The pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 4, further comprising a silicate oligomer (F) having a structure represented by the following chemical formula (1):
In the above chemical 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;
Each of X ¹ and X ² independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a phenyl group;
n is an integer of 1 or more and 100 or less.   The pressure-sensitive adhesive composition for an optical film according to claim 5, wherein the silicate oligomer (F) comprises a methyl silicate oligomer.   The pressure-sensitive adhesive composition for an optical film according to claim 5 or 6, wherein the weight average molecular weight of the silicate oligomer (F) is 300 or more and 30,000 or less.   The crosslinking agent (C) includes at least one 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. The adhesive composition for optical films of any one of 7.   The pressure-sensitive adhesive composition for an optical film according to claim 8, wherein the isocyanate-based crosslinking agent contains an isocyanate compound having a number average molecular weight of 900 or more and 10,000 or less.   The adhesive composition for optical films of any one of Claims 1-9 which further contain a peroxide (G).   The pressure-sensitive adhesive composition for an optical film according to claim 10, wherein the peroxide (G) has a half-life temperature of 80 ° C. or more and 125 ° C. or less for one minute.   The pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 11, further comprising a high softening point resin (H).   The adhesive composition for optical films of Claim 12 whose said high softening point resin (H) is rosin ester-type resin.   The copolymer (A) according to any one of claims 1 to 13, wherein the copolymer (A) contains a structural unit (a ') derived from a (meth) acrylic monomer whose homopolymer has a glass transition temperature of 50 ° C or higher. Adhesive composition for optical film.   (Meth) acrylic component containing a structural unit derived from a (meth) acrylic monomer having a weight average molecular weight (Mw) smaller than that of the (meth) acrylate copolymer (A) and having a glass transition temperature of 50 ° C. or higher of the homopolymer The pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 14, further comprising a system (co) polymer (I).   The pressure-sensitive adhesive composition for an optical film according to claim 15, wherein the weight average molecular weight (Mw) of the (meth) acrylic (co) polymer (I) is 500 or more and 100,000 or less.   The adhesive layer for optical films which is formed from the adhesive composition for optical films of any one of Claims 1-16. An adhesive layer for an optical film according to claim 17;
A first optical film provided on one side of the pressure-sensitive adhesive layer,
An optical member.   The optical member according to claim 18, further comprising glass or a second optical film on the surface of the pressure-sensitive adhesive layer opposite to the surface on which the first optical film is provided.   The optical member according to claim 18, further comprising at least one easy-adhesion treatment layer between the first optical film and the pressure-sensitive adhesive layer for an optical film. It has a first easy-adhesion treatment layer on the side of the first optical film facing the pressure-sensitive adhesive layer for an optical film,
The optical member according to claim 20, further comprising a second easy-adhesion treatment layer on a surface of the pressure-sensitive adhesive layer for an optical film facing the first optical film.   The optical member according to any one of claims 18 to 21, wherein the first optical film is a polarizing plate.   An image display apparatus using at least one optical member according to any one of claims 18 to 22.   A pressure-sensitive adhesive for an optical film, which comprises applying the pressure-sensitive adhesive composition for an optical film according to any one of claims 1 to 16 onto a release-treated release sheet and then heat treating it to cause a crosslinking reaction. How to make a layer.   The method for producing an adhesive film for an optical film according to claim 24, wherein the temperature of the heat treatment is 80 ° C or more and 120 ° C or less.