JP6463167B2 - Adhesive for optical member and optical laminate - Google Patents

Description

  The present invention relates to an adhesive for optical members and an optical laminate.

In recent years, the use of liquid crystal elements in vehicles, outdoor instruments or PC displays, televisions, and the like has been expanded, and the use environment has become very severe. The liquid crystal element has a structure in which a liquid crystal material is sandwiched between two substrates (eg, a glass plate), and a polarizing plate is attached to the surface of the substrate via an adhesive layer. Accordingly, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is also required to have durability under high temperature and high humidity heat.
The pressure-sensitive adhesive layer for polarizing plate is usually stuck on the polarizing plate with a cover film peeled off on one side during the production of the liquid crystal element, and then the cover film is peeled off to expose the pressure-sensitive adhesive layer. And then pasted on the substrate. At that time, static electricity is generated because the insulating properties of the cover film and the polarizing plate are high, which may adversely affect the orientation of the liquid crystal or damage electronic components.
For this reason, antistatic performance is also required for the pressure-sensitive adhesive for polarizing plates, and a technology for incorporating an ionic compound into the base polymer constituting the pressure-sensitive adhesive has been reported as a pressure-sensitive adhesive for polarizing plates having antistatic performance. ing.

  For example, Patent Document 1 discloses an adhesive containing an acrylic resin obtained by polymerizing a specific (meth) acrylic acid ester, an ionic compound having an organic cation and being solid at room temperature, and a crosslinking agent. A composition is described. Patent Document 2 describes a surface protective sheet for an optical member containing an ionic compound having a melting point of 50 ° C. or higher and a base polymer having a glass transition temperature of 0 ° C. or lower.

JP 2010-66756 A JP 2009-19162 A

  Usually, a polarizing plate has a structure in which protective films are bonded to both sides of a polarizer. The pressure-sensitive adhesive layer is formed in contact with the protective film. As the protective film, a triacetyl cellulose (TAC) film is generally used. However, according to the study by the present inventors, the polymer component constituting the protective film is hydrolyzed by the ionic compound contained in the pressure-sensitive adhesive layer in a wet and hot environment, and abnormal appearance such as cracks in the polarizing plate, polarization It has been found that there are problems in long-term reliability, such as cracking and peeling of the pressure-sensitive adhesive due to strong contraction of the plate, and deterioration in optical characteristics due to insufficient protection of the polarizer. In addition, due to the further thinning of the members and the widening of the range of use in recent years, it has been demanded that the above problems do not occur even under conditions more severe than those of conventional long-term reliability tests.

  In addition to the TAC film, a cycloolefin-based (COP) film has been used as a protective film. COP films have the advantage of being less brittle and hygroscopic than TAC films. However, since the COP film has a shrinkage ratio different from that of the TAC film, there is a problem that “light leakage” of the image display device due to the shrinkage of the polyvinyl alcohol film which is the main component of the polarizer cannot be sufficiently suppressed. . Furthermore, since the COP film has a polarity different from that of the TAC film, the adhesive used for bonding the TAC film and the adherend is used particularly when the adhesive is used for bonding the COP film and the adherend. As a result, there is a problem that floating or peeling occurs at the time of heat or wet heat, and the required performance is not reached in the workability at the time of punching or reworkability.

  An object of the present invention is to provide a pressure-sensitive adhesive for optical members and an optical laminate capable of forming a pressure-sensitive adhesive layer having excellent antistatic performance and durability under high temperature and high humidity regardless of the type of polarizing plate. Is to provide.

The present inventors diligently studied to solve the above problems. As a result, a (meth) acrylic polymer obtained from a polymerizable monomer containing a specific (meth) acrylic acid ester, a crosslinking agent, and a pressure-sensitive adhesive obtained from a specific ionic compound can solve the above problems. As a result, the present invention has been completed.
The present invention includes, for example, the following 1.-6. It is.

1. An adhesive for optical members obtained from an acrylic polymer (A), a crosslinking agent (B), and an ionic compound (C),
As a monomer component constituting the acrylic polymer (A), (a2) 0.1 to 10% by weight of a carboxyl group-containing monomer is contained, and the crosslinking agent (B) is 100% by weight of the acrylic polymer (A). 4 to 30 parts by weight with respect to parts, and the ionic compound (C) is represented by a cation represented by the following chemical formula (1), a bis (fluorosulfonyl) imide anion, and a bis (trifluoromethylsulfonyl) imide anion. It is an ionic compound composed of selected anions, and the storage elastic modulus at 23 ° C. is 2.0 × 10 ⁵ Pa to 5.5 × 10 ⁶ Pa and the storage elastic modulus at 80 ° C. is 1.0 × 10 ⁵ Pa to An adhesive for optical members, which is 2.0 × 10 ⁶ Pa .
... (1)
In formula (1), R ¹¹ and R ¹² are each independently an alkyl group.
2. 1 above. (A1-1) 41 to 99.9% by weight of (meth) acrylic acid ester having a polyoxyalkylene group or an alkoxyalkyl group is contained as a monomer component constituting the acrylic polymer (A) described in 1. 1. The adhesive for optical members described in 1.
3.1. As a monomer component constituting the acrylic polymer (A) described in 1), (a1-2) (meth) acrylic acid alkyl ester is contained in a proportion of 70 to 99.9% by weight. The adhesive for optical members described in 1.
4). A polarizing plate having a protective film on at least one surface, and the above 1. An optical layered body in which an adhesive layer made of the adhesive for optical members of 3 to 3 is laminated.
5. 4. The protective film is a cellulose film or a cycloolefin film. The optical laminated body as described in.
6). An optical member having a cycloolefin polymer layer, and 2. on the cycloolefin polymer layer. An optical laminate comprising an adhesive layer made of the adhesive for optical members described in 1 above.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in antistatic performance, the adhesive for optical members which can form the adhesive layer provided with durability under high temperature, high humidity, and an optical laminated body can be provided.

Hereinafter, the pressure-sensitive adhesive for optical members and the optical laminate of the present invention will be described. Hereinafter, the pressure-sensitive adhesive for optical members of the present invention is also simply referred to as “pressure-sensitive adhesive”.
In this specification, acrylic and methacryl are collectively referred to as “(meth) acryl”.
(Adhesive for optical members)

  The pressure-sensitive adhesive for optical members of the present invention contains a (meth) acrylic polymer (A), a crosslinking agent (B), and an ionic compound (C) described below. The said adhesive for optical members may contain a silane coupling agent (D) as needed, and may contain an organic solvent (E).

((Meth) acrylic polymer (A))
The (meth) acrylic polymer (A) is obtained by radical polymerization of a polymerizable monomer mixture containing a monomer (a2) having carboxyl and a (meth) acrylic acid ester having no crosslinkable group. Copolymer.

  As a 1st aspect of the (meth) acrylic-type polymer (A) of this invention, the (meth) acrylic acid which has a polyoxyalkylene group or an alkoxyalkyl group as said (meth) acrylic acid ester which does not have a crosslinkable group. The acid ester (a1-1) is contained at a ratio of 41 to 99.9% by mass with respect to the total amount of the polymerizable monomer mixture.

  Further, in the first embodiment, the (meth) acrylic acid alkyl ester (a1-2) having no crosslinkable group is further contained in a proportion of 0 to 58.9% by mass with respect to the total amount of the polymerizable monomer mixture. May be.

  Furthermore, the monomer (a3) having a crosslinkable group other than a carboxyl group is in a proportion of 0 to 10% by mass with respect to the total amount of the polymerizable monomer mixture, and other monomers other than the above are used as polymerizable monomers. It can contain in the ratio of 0-10 mass% with respect to a body mixture whole quantity.

  Hereinafter, the (meth) acrylic acid ester (a1-1) is also referred to as “monomer (a1-1)”, and the (meth) acrylic acid alkyl ester (a1-2) is referred to as “monomer (a1-2)”. ) ", The monomer having a carboxyl group is also referred to as" monomer (a2) ", the crosslinkable group-containing monomer (a3) other than the carboxyl group is also referred to as" monomer (a3) ", The other monomer (a4) is also referred to as “monomer (a4)”.

(Monomer (a1-1))
The monomer (a1-1) is a (meth) acrylic acid ester having a polyoxyalkylene group or an alkoxyalkyl group.
A monomer (a1-1) is represented by Formula (2), for example.
_{^{CH 2 = CR 1 -COOR 2 ···}} (2)
R ¹ is a hydrogen atom or a methyl group, and R ² is a group represented by the formula (3).
-(R ³ O) nR ⁴ (3)

R ³ is an alkylene group, R ⁴ is an alkyl group, and n is an integer of 1 or more. Carbon number of an alkylene group is 1-10 normally, Preferably it is 1-5. Carbon number of an alkyl group is 1-10 normally, Preferably it is 1-4. n is preferably 1 to 20, more preferably 1 to 4, and still more preferably 1 to 2.

Examples of the monomer (a1-1) include alkoxyalkyl (meth) acrylate and alkoxypolyalkylene glycol (meth) acrylate.
Examples of the alkoxyalkyl (meth) acrylate include methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl ( Examples include meth) acrylate, 4-methoxybutyl (meth) acrylate, and 4-ethoxybutyl (meth) acrylate.
Examples of the alkoxypolyalkylene glycol (meth) acrylate include methoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, ethoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol ( And (meth) acrylate.

Among these, as the monomer (a1-1), an alkoxyalkyl (meth) acrylate in which R ² _{2 in the} formula (2) is an alkoxyalkyl group is preferable from the viewpoint of reactivity.
A monomer (a1-1) may be used individually by 1 type, and may use 2 or more types.

  In 100% by mass of the polymerizable monomer forming the (meth) acrylic polymer (A), the amount of the monomer (a1-1) used is from 41% by mass to 99.9% by mass, and 50 The mass is preferably from 9% by mass to 99.5% by mass, more preferably from 60% by mass to 99.3% by mass.

  If the usage-amount of a monomer (a1-1) is 41 mass% or more, the adhesive layer formed from the adhesive composition containing a (meth) acrylic-type polymer (A) will show high polarity. Excellent adhesion to polarizing plates and substrates (particularly glass plates). In particular, even when a polarizing plate having a protective film of COP, which is usually difficult to adhere, is used, it is possible to develop good substrate adhesion. Therefore, even under high temperature or high humidity heat, the pressure-sensitive adhesive layer does not float or peel off from the polarizing plate or the substrate, and the pressure-sensitive adhesive layer has excellent durability. Moreover, since it is excellent in adhesiveness with the base material, reworkability is good, and further, adhesion of the pressure-sensitive adhesive layer to a punching blade, a peripheral polarizing plate and the like hardly occurs and workability is excellent. When the amount of the monomer (a1-1) used is 50% by mass or more, the effect is more remarkable. If the amount of the monomer (a1-1) used is within the above range, the affinity between the (meth) acrylic polymer (A) and the ionic compound (B) described later is good, and the ionic compound (B) Bleed can be suppressed.

(Monomer (a1-2))
The monomer (a1-2) is a (meth) acrylic acid alkyl ester having no polyoxyalkylene group, alkoxyalkyl group or crosslinkable group.
A monomer (a1-2) is represented by Formula (4), for example.
_{^{CH 2 = CR 5 -COOR 6 ···}} (4)

R ⁵ is a hydrogen atom or a methyl group, and R ⁶ is an organic group that does not have any of a polyoxyalkylene group, an alkoxyalkyl group, and a crosslinkable group.
The organic group in R ⁶ is an alkyl group having 1 to 24 carbon atoms.

Examples of the monomer (a1-2) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) ) Acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate , Isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, Lil (meth) acrylate, isostearyl (meth) acrylate.
A monomer (a1-2) may be used individually by 1 type, and may use 2 or more types.

  In 100% by mass of the polymerizable monomer forming the (meth) acrylic polymer (A), the amount of the monomer (a1-2) used is 0% by mass or more and 58.9% by mass or less. The content is preferably from mass% to 49.83 mass%, more preferably from 5 mass% to 39.75 mass%.

(Monomer (a2))
The monomer (a2) is a monomer containing a carboxyl group.
By using the monomer (a2) as the polymerizable monomer constituting the (meth) acrylic polymer (A), the crosslinking point that can be crosslinked by the crosslinking agent (B) is used as the (meth) acrylic polymer. (A) can be introduced.
A monomer (a2) is represented by Formula (5), for example.
CH ₂ = CR ⁷ -COOR ⁸ (5)

R ⁷ is a hydrogen atom or a methyl group, and examples of the organic group in R ⁸ include hydrogen and a carboxyl group-substituted aliphatic group having 1 to 12 carbon atoms.

Examples of the monomer (a2) include a carboxyl group-containing (meth) acrylate.
Examples of the carboxyl group-containing (meth) acrylate include (meth) acrylic acid, β-carboxyethyl (meth) acrylate, and 5-carboxypentyl (meth) acrylate.
Examples of the monomer (a2) include ethylenically unsaturated carboxylic acids in addition to the compound represented by the formula (5). Examples of the ethylenically unsaturated carboxylic acid include crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid.
A monomer (a2) may be used individually by 1 type, and may use 2 or more types.

  In 100% by mass of the polymerizable monomer that forms the (meth) acrylic polymer (A), the amount of the monomer (a2) used is such that durability and stress relaxation characteristics due to appropriate crosslinking and high polarity are increased. From the viewpoint of improving adhesion with the adherend due to application, it is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.15 to 8% by mass, and further preferably 0.2 to 5% by mass. .

(Monomer (a3))
The monomer (a3) is a monomer (a3) having a crosslinkable group other than a carboxyl group.
By using the monomer (a3) as the polymerizable monomer constituting the (meth) acrylic polymer (A), it is possible to adjust the degree of crosslinking, improve the adhesion to the substrate and the adherend, and the crosslinking agent ( The compatibility of B) can be improved.
A monomer (a3) is represented by Formula (6), for example.
CH ₂ = CR ⁹ -COOR ¹⁰ (6)

R ⁹ is a hydrogen atom or a methyl group, and R ¹⁰ is an organic group having a crosslinkable group. Examples of the crosslinkable group include a hydroxyl group and an amino group.
Examples of the organic group for R ¹⁰ include a hydroxyalkyl group having 1 to 12 carbon atoms and an N-alkyl-substituted aminoalkyl group having 1 to 12 carbon atoms.

Examples of the monomer (a3) include a hydroxyl group-containing (meth) acrylate and an amino group-containing (meth) acrylate.
Examples of the hydroxyl group-containing (meth) acrylate include hydroxyalkyl (meth) acrylate, and examples include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4 -Hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl (meth) acrylate.
Examples of amino group-containing (meth) acrylates include N-alkyl-substituted aminoalkyl (meth) acrylates, and examples include monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, and monomethylaminopropyl (meth). Examples thereof include acrylate, monoethylaminopropyl (meth) acrylate, and dimethylaminoethyl (meth) acrylate.
A monomer (a3) may be used individually by 1 type, and may use 2 or more types.

  In 100% by mass of the polymerizable monomer forming the (meth) acrylic polymer (A), the amount of the monomer (a3) used is such that if the amount used is too small, the compatibility of the crosslinking agent and the base material From the viewpoint of poor adhesion and reduced tackiness when the amount used is too large, preferably 0% by mass to 10% by mass, more preferably 0.02% by mass to 8% by mass, Preferably they are 0.05 mass% or more and 5 mass% or less.

(Monomer (a4))
Examples of the monomer (a4) include vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene, α-methyl Examples thereof include styrene monomers such as styrene; diene monomers such as butadiene, isoprene and chloroprene; nitrile monomers such as (meth) acrylonitrile, alicyclic groups, and aromatic ring-containing (meth) acrylates. Examples of the alicyclic group or aromatic ring-containing (meth) acrylate include cyclohexyl (meth) acrylate, benzyl (meth) acrylate, and phenyl (meth) acrylate.
Moreover, (meth) acrylamides can also be mentioned. Examples of (meth) acrylamides include N-methacrylate such as (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, and N-hexyl (meth) acrylamide. Monoalkyl-substituted acrylamides; N, N-dialkyl-substituted acrylamides such as N, N-dimethylacrylamide and N, N-dimethylmethacrylamide. Furthermore, macromonomers such as (meth) acrylic macromonomers and styrene macromonomers can be used.
A monomer (a4) may be used individually by 1 type, and may use 2 or more types.

  A monomer (a4) can be used in the range which does not impair the effect of this invention, and is 0 mass% or more in 100 mass% of polymerizable monomers which form a (meth) acrylic-type polymer (A). It is used in the range of 10% by mass or less.

The 2nd aspect of the (meth) acrylic-type polymer (A) of this invention is 70-99.9 mass% of (meth) acrylic-acid alkylester (a1-2) with respect to the polymerizable monomer mixture whole quantity. The monomer (a2) containing a carboxyl group is contained at a ratio of 0.1 to 10% by mass with respect to the total amount of the polymerizable monomer mixture.
In the second embodiment, the (meth) acrylic acid ester (a1-1) further having a polyoxyalkylene group or alkoxyalkyl group having no crosslinkable group is 0 to 29 with respect to the total amount of the polymerizable monomer mixture. You may contain in the ratio of .9 mass%.

Furthermore, the monomer (a3) having a crosslinkable group other than the carboxyl group is polymerized with the other monomer (a4) other than the above in a proportion of 0 to 10% by mass with respect to the total amount of the polymerizable monomer mixture. It can contain in the ratio of 0-10 mass% with respect to the whole quantity of a monomer mixture.
As the monomer (a1-1) to the monomer (a4), the same monomers as in the first embodiment can be used.
In the second embodiment, the monomer (a1-1) is 0 to 29.9% by mass, preferably 0 in 100% by mass of the polymerizable monomer that forms the (meth) acrylic polymer (A). -29.75 mass%.

  In the second embodiment, the monomer (a1-2) is an alkyl group having 1 to 2 carbon atoms (meth) acrylic acid alkyl ester (a1-2-1) or an alkyl group having 3 to 10 carbon atoms. It is preferably a (meth) acrylic acid alkyl ester (a1-2-2). From the viewpoint of maintaining cohesive force in a high temperature environment and improving adhesion by increasing the polarity, the alkyl group having 1 to 2 carbon atoms ( It contains 0 to 30% by weight of 100% by weight of the polymerizable monomer forming the acrylic polymer (A) of the alkyl methacrylate (a1-2-1), and has tackiness and cohesive strength. From the viewpoint of balancing the adhesion performance, the alkyl group having 3 to 10 carbon atoms (meth) acrylic acid alkyl ester (a1-2-2) is 70 to 99.9% by mass, and further 70 to 99.5% by mass. It is preferable to contain.

  In the second embodiment, the monomer (a2) is used in an amount of (meth) acrylic from the viewpoints of durability by moderate crosslinking and expression of stress relaxation characteristics, and improvement in adhesion to the adherend by imparting high polarity. It is 0.1-10 mass% in 100 mass% of polymerizable monomers which form a type | system | group polymer (A), Preferably it is 0.2-5 mass%.

  The amount of the monomer (a3) used is the polymerizable monomer 100 that forms the (meth) acrylic polymer (A) from the viewpoint of improving the compatibility of the crosslinking agent (B) and the adhesion to the substrate. In mass%, it is 0-10 mass%, More preferably, it is 0.05-5 mass%.

  A monomer (a4) can be used in the range which does not impair the effect of this invention, and 0-10 mass in 100 mass% of polymerizable monomers which form a (meth) acrylic-type polymer (A). Used in the range of%.

(Production conditions for (meth) acrylic polymer (A))
The (meth) acrylic polymer (A) can be produced by, for example, a conventionally known polymerization method such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, a suspension polymerization method, and among these, the solution polymerization method Is preferred. Specifically, a polymerization solvent and a polymerizable monomer are charged into a reaction vessel, a polymerization initiator is added in an inert gas atmosphere such as nitrogen gas, and the reaction start temperature is usually 40 to 100 ° C., preferably 50 The reaction system is maintained at a temperature of 50 to 90 ° C., preferably 60 to 90 ° C., and is allowed to react for 4 to 20 hours.

Examples of the polymerization initiator include azo initiators and peroxide polymerization initiators.
Examples of the azo initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2- Cyclopropylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbohydrate) Nitrile), 2- (carbamoylazo) isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′- Azobis (N, N′-dimethyleneisobutylamidine), 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) -propionamide), 2,2′-azo (Isobutylamide) dihydrate, 4,4′-azobis (4-cyanopentanoic acid), 2,2′-azobis (2-cyanopropanol), dimethyl-2,2′-azobis (2-methylpropionate) Azo compounds such as 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) propionamide).
Examples of peroxide polymerization initiators include t-butyl hydroperoxide, cumene hydroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, and di-i-propyl peroxydicarbonate. , Di-2-ethylhexyl peroxydicarbonate, t-butyl peroxybivalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-bis (4,4- Di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,4-di-α-cumylperoxycyclohexyl) ) Propane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) Butane, 2,2-bis (4,4-di -t- octylperoxycarbonyl cyclohexyl), and butane.
A polymerization initiator may be used individually by 1 type, and may use 2 or more types.
It is not limited that the polymerization initiator is added a plurality of times during the polymerization.

  A polymerization initiator is 0.001-5 mass parts normally with respect to 100 mass parts of polymerizable monomers which form a (meth) acrylic-type polymer (A), Preferably it is the range of 0.005-3 mass parts. Used in quantity. Moreover, you may add suitably a polymerization initiator, a chain transfer agent, a polymerizable monomer, and a polymerization solvent during the said polymerization reaction.

Examples of the polymerization solvent used for the solution polymerization include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; cyclopentane, Cycloaliphatic hydrocarbons such as cyclohexane, cycloheptane, cyclooctane; ethers such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenylethyl ether, diphenyl ether; chloroform, Halogenated hydrocarbons such as carbon tetrachloride, 1,2-dichloroethane, chlorobenzene; esters such as ethyl acetate, propyl acetate, butyl acetate, methyl propionate; acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone Ketones such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethyl sulfoxide and sulfolane Etc.
A polymerization solvent may be used individually by 1 type, and may use 2 or more types.

(Physical properties and content of (meth) acrylic polymer (A))
The (meth) acrylic polymer (A) has a weight average molecular weight (Mw) measured by, for example, a gel permeation chromatography method (GPC method), which is usually 200,000 or more in terms of polystyrene, preferably The polymer (A) is 300,000 to 1,200,000, more preferably 400,000 to 1.1 million, and still more preferably 500,000 to 1,000,000. It is preferable that Mw is not less than the lower limit in terms of excellent durability and cohesive strength of the pressure-sensitive adhesive layer. It is preferable that Mw is equal to or less than the upper limit in terms of good coating properties and wettability of the pressure-sensitive adhesive composition.

  The polymer (A) has a molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) measured by GPC method of usually 2 to 60, preferably 3 to 45, more preferably 3 to 20, More preferably, it is 3-10. It is preferable that Mw / Mn is equal to or more than the lower limit in terms of adhesion to a substrate or a polarizing plate. When Mw / Mn is less than or equal to the above upper limit, heat resistance is excellent, which is preferable in terms of maintaining durability.

(Crosslinking agent (B))
The pressure-sensitive adhesive for optical members of the present invention contains a crosslinking agent (B). A crosslinking agent (B) is suitably selected by the crosslinkable group which can be introduce | transduced into a (meth) acrylic-type polymer (A), For example, an isocyanate compound, an epoxy compound, and a metal chelate compound can be used. From the viewpoint of adhesive strength, wettability, light leakage suppression, and stability over time of the coated product, it is preferable that the isocyanate group in one molecule is a polyfunctional isocyanate compound having two or more.

  As the isocyanate compound, an isocyanate compound having two or more isocyanate groups in one molecule is usually used, preferably 2 to 8, and more preferably 3 to 6. When the isocyanate group in one molecule is in the above range, it is preferable from the viewpoint of the crosslinking reaction efficiency between the (meth) acrylic polymer (A) and the isocyanate compound and the flexibility of the pressure-sensitive adhesive layer.

Examples of the diisocyanate compound having two isocyanate groups in one molecule include aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate. Aliphatic diisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, 2,2,4-trimethyl. Examples include aliphatic diisocyanates having 4 to 30 carbon atoms such as -1,6-hexamethylene diisocyanate. As the alicyclic diisocyanate, an alicyclic group having 7 to 30 carbon atoms such as isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, etc. Diisocyanate is mentioned. Examples of the aromatic diisocyanate include aromatic diisocyanates having 8 to 30 carbon atoms such as phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, and diphenylpropane diisocyanate.
Examples of the isocyanate compound having three or more isocyanate groups in one molecule include aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate. Specifically, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, and 4,4 ′, 4 ″ -triphenylmethane triisocyanate are exemplified.
Examples of the isocyanate compound include multimers (for example, dimers or trimers, biurets, isocyanurates), derivatives (for example, polyvalent compounds) of the above isocyanate compounds having two or three isocyanate groups. Addition reaction product of alcohol and two or more molecules of diisocyanate compound), polymer. Examples of the polyhydric alcohol in the derivative include trivalent or higher alcohols such as trimethylolpropane, glycerin and pentaerythritol as low molecular weight polyhydric alcohols; high molecular weight polyhydric alcohols such as polyether polyols, Examples include polyester polyol, acrylic polyol, polybutadiene polyol, and polyisoprene polyol.
Examples of such isocyanate compounds include diphenylmethane diisocyanate trimer, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate or tolylene diisocyanate biuret or isocyanurate, trimethylolpropane and tolylene diisocyanate or xylylene diisocyanate. Reaction product (for example, a trimolecular adduct of tolylene diisocyanate or xylylene diisocyanate), a reaction product of trimethylolpropane and hexamethylene diisocyanate (for example, a trimolecular adduct of hexamethylene diisocyanate), a polyether polyisocyanate, Polyester polyisocyanate is mentioned.

  Among the isocyanate compounds, the reaction product of trimethylolpropane and tolylene diisocyanate or xylylene diisocyanate (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd., Soken Chemical ( TD-75, etc.), isocyanurate of hexamethylene diisocyanate or tolylene diisocyanate (Asahi Kasei Kogyo Co., Ltd. TSE-100, Nippon Polyurethane Industry Co., Ltd. 2050, etc.) is preferable.

  Examples of the epoxy compound include compounds having two or more epoxy groups in the molecule. For example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexane. Diol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′- Diamine glycidylaminomethyl). Examples of commercially available products include E-5CM manufactured by Soken Chemical Co., Ltd. and E-5XM manufactured by Soken Chemical Co., Ltd.

  As the metal chelate compound, for example, an alkoxide, acetylacetone, ethyl acetoacetate or the like is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium Compounds. Specific examples include aluminum isopropylate, aluminum secondary butyrate, aluminum ethyl acetoacetate / diisopropylate, aluminum trisethyl acetoacetate, and aluminum trisacetylacetonate.

By crosslinking the (meth) acrylic polymer (A) with the crosslinking agent (B), a crosslinked body (network polymer) can be formed, and an adhesive layer excellent in heat resistance can be obtained.
A crosslinking agent (B) may be used individually by 1 type, and may use 2 or more types.
In the pressure-sensitive adhesive composition of the present invention, the content of the crosslinking agent (B) is appropriately selected according to the (meth) acrylic polymer (A), and 100 parts by mass of the (meth) acrylic polymer (A). It is preferable that it is 4-30 mass parts with respect to this, More preferably, it is 4-25 mass parts.
By blending the cross-linking agent (B) within the above range, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive for optical members of the present invention exhibits a suitable balance of stress relaxation characteristics and cohesive force, and has sufficient heat resistance. Can be obtained. Moreover, it is excellent in flexibility and adhesion.

(Ionic compound (C))
The pressure-sensitive adhesive for optical members of the present invention comprises an anion selected from a bis (fluorosulfonyl) imide anion and / or a bis (trifluoromethylsulfonyl) imide anion, and a 4-alkyl-N— represented by the following formula (1): An ionic compound (C) comprising an alkylpyridinium cation is contained.

... (1)
In formula (1), R ¹¹ and R ¹² are each independently an alkyl group.
When the pressure-sensitive adhesive for optical members contains the ionic compound (C), the surface resistance value of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive for optical members of the present invention is reduced, and a pressure-sensitive adhesive layer having antistatic performance is obtained. be able to.

  The polarizing plate to which the pressure-sensitive adhesive layer is attached generally has a protective film for protecting the polarizer, and as the protective film, a cellulose film such as triacetyl cellulose, Examples include polycarbonate films, polyethersulfone films, cycloolefin-based (COP) films, and cellulose films such as triacetyl cellulose are often used.

  Conventionally known ionic compounds have many ionic compounds that promote the hydrolysis reaction of triacetyl cellulose, while the ionic compound (C) of the present invention hardly causes the hydrolysis reaction of triacetyl cellulose. For this reason, even if a pressure-sensitive adhesive layer containing the ionic compound (C) is pasted on a protective film made of a TAC film, the pressure-sensitive adhesive layer exposed to the wet heat environment may corrode the protective film made of the TAC film. Therefore, an optical laminate having excellent long-term reliability can be obtained.

Even when the protective film is a COP film, since the ionic compound (C) of the present invention is excellent in compatibility with the acrylic polymer (A), a pressure-sensitive adhesive layer containing the ionic compound (C), Even if the COP film protective film subjected to the corona treatment is bonded, the surface physical properties of the COP film are not impaired. For this reason, even if a pressure-sensitive adhesive layer containing the ionic compound (C) is pasted on a protective film made of a COP film, the pressure-sensitive adhesive layer exposed to the wet heat environment may corrode the protective film made of the COP film. Therefore, an optical laminate having excellent long-term reliability can be obtained.

Anions contained in the ionic compound (C) include N, N-bis (fluorosulfonyl) imide ((FSO ₂ ) ₂ N ⁻ ) and N, N-bis (trifluoromethanesulfonyl) imide ((CF ₃ SO ₂ ) _2. N ^-) is selected from the group consisting of. These anions are preferable for obtaining an optical laminate excellent in long-term reliability because hydrolysis of the TAC film is not promoted. More preferred is a bis (trifluoromethylsulfonyl) imide anion.

Examples of the organic cation contained in the ionic compound (C) include a 4-alkyl-N-alkylpyridinium cation represented by the formula (1) and derivatives thereof.

... (1)
In formula (1), R ¹¹ and R ¹² are each independently an alkyl group.
Preferably, R ¹¹ is an alkyl group having 1 to 8 carbon atoms, and R ¹² is an alkyl group having 1 to 18 carbon atoms. Since the pressure-sensitive adhesive layer excellent by wet heat resistance can be obtained, more ^{preferably, R 11} is an alkyl group of 1 to 5 carbon ^{atoms, R 12} is an alkyl group having 1 to 12 carbon atoms, more ^{preferably, R 11} Is an alkyl group having 1 to 3 carbon atoms, and R ¹² is an alkyl group having 8 carbon atoms. It is preferable that both of the alkyl groups in R ¹¹ and R ¹² are n-alkyl groups. Moreover, it is desirable that the alkyl group has a carbon number within the above range in order to develop appropriate compatibility between the (meth) acrylic polymer (A) and the ionic compound (C). By exhibiting appropriate compatibility, good initial antistatic performance is exhibited, and deterioration of antistatic performance due to bleeding over time and deterioration of adhesion to an adherend are suppressed. Furthermore, it is excellent in moisture and heat resistance.
Examples of the 4-alkyl-N-alkylpyridinium cation represented by the formula (1) include 4-methyl-N-octylpyridinium cation and 4-methyl-N-butylpyridinium cation. The reason is not clear, but if it is an ionic compound having the above structure, it is particularly excellent in stabilization after being formed into a coating film, and the antistatic performance and adhesive properties can be kept constant.

  The melting point of the ionic compound (C) is preferably less than 25 ° C, and more preferably less than 10 ° C. The ionic compound (C) having a melting point in the above range has good compatibility with the pressure-sensitive adhesive, and can exist stably even after being formed into a coating film. The melting point can be measured by differential scanning calorimetry (DSC).

  Specific examples of the ionic compound (C) include 4-methyl-N-octylpyridinium / N, N-bis (trifluoromethanesulfonyl) imide, 4-methyl-N-octylpyridinium / N, N-bis (fluoro Sulfonyl) imide, 4-methyl-N-butylpyridinium / N, N-bis (fluorosulfonyl) imide, and the like. Preferably, 4-methyl-N-octylpyridinium / N, N-bis (trifluoromethanesulfonyl) imide, 4-methyl-N-octylpyridinium / N, N-bis (fluorosulfonyl) imide, more preferably 4- Methyl-N-octylpyridinium / N, N-bis (trifluoromethanesulfonyl) imide.

  The content of the ionic compound (C) in the pressure-sensitive adhesive for optical members of the present invention is usually more than 0 parts by mass and 15 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer (A) from the viewpoint of durability. Part or less, preferably 0.1 to 10 parts by weight, more preferably 0.1 to 8 parts by weight.

(Silane coupling agent (D))
The pressure-sensitive adhesive composition of the present invention may contain a silane coupling agent (D) in addition to the compound. By using the silane coupling agent (D), the pressure-sensitive adhesive layer can be firmly adhered to a substrate such as a glass plate, which can contribute to the prevention of peeling of the polarizing plate in a high-humidity heat environment.

  Examples of the silane coupling agent (D) include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, Polymerizable unsaturated group-containing silane coupling agents such as 3-methacryloxypropyltriethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane Epoxy group-containing silane coupling agents such as 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, 3-aminopropyl Pyrtriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1, Examples include amino group-containing silane coupling agents such as 3-dimethyl-butylidene) propylamine and N-phenyl-3-aminopropyltrimethoxysilane; halogen-containing silane coupling agents such as 3-chloropropyltrimethoxysilane. From the viewpoint of improving adhesion, those containing a functional group such as an epoxy group capable of reacting with a carboxyl group in the pressure-sensitive adhesive are preferable.

  Content of the silane coupling agent (D) in the adhesive composition for polarizing plates of this invention is 0-1 mass part normally with respect to 100 mass parts of (meth) acrylic-type polymers (A), Preferably it is 0. 0.01 to 1 part by mass, more preferably 0.05 to 0.5 part by mass.

(Organic solvent (E))
The pressure-sensitive adhesive for optical members of the present invention is preferably obtained using a pressure-sensitive adhesive composition containing an organic solvent (E) in order to adjust the coating property. As an organic solvent, the polymerization solvent demonstrated in the column of (The manufacturing conditions of (meth) acrylic-type polymer (A)) is mentioned. For example, a pressure-sensitive adhesive composition can be prepared by mixing a polymer solution containing a (meth) acrylic polymer (A) and a polymerization solvent, a crosslinking agent (B), and an ionic compound (C). . In the pressure-sensitive adhesive composition, the content of the organic solvent is usually 50 to 90% by mass, preferably 60 to 90% by mass.
In the present specification, “solid content” refers to all components excluding the organic solvent (E) among the components contained in the pressure-sensitive adhesive composition, and “solid content concentration” refers to the pressure-sensitive adhesive composition 100. The ratio of the said solid content with respect to the mass% is said.

(Additive)
In addition to the above components, the pressure-sensitive adhesive for optical members of the present invention is an acrylic low molecular weight polymer having an Mw of 1000 to 20000, an antioxidant, a light stabilizer, a metal corrosion inhibitor, an adhesive, and the like within a range not impairing the effects of the present invention. You may contain 1 type, or 2 or more types selected from an imparting agent, a plasticizer, a crosslinking accelerator, surfactant, and a rework agent.

(Preparation of pressure-sensitive adhesive for optical members)
The pressure-sensitive adhesive for optical members of the present invention comprises a (meth) acrylic polymer (A), a cross-linking agent (B), an ionic compound (C), and other components as required in a conventionally known method. Can be prepared by mixing. For example, a crosslinking agent (B) and an ionic compound (C) are added to a polymer solution containing the (meth) acrylic polymer (A) obtained when the (meth) acrylic polymer (A) is synthesized. And blending with other components as necessary.
The pressure-sensitive adhesive for optical members is excellent in adhesion to a glass substrate or a polarizing plate and durability under high temperature and high humidity, and therefore can be suitably used for bonding a polarizing plate and a glass substrate.

(Adhesive layer)
The pressure-sensitive adhesive layer of the present invention is formed from the above-mentioned pressure-sensitive adhesive for optical members. For example, the pressure-sensitive adhesive layer can be obtained by proceeding with the crosslinking reaction in the above-mentioned pressure-sensitive adhesive, specifically, by crosslinking the (meth) acrylic polymer (A) with the crosslinking agent (B).

The conditions for forming the pressure-sensitive adhesive layer are, for example, as follows. The pressure-sensitive adhesive composition prepared by coating with an organic solvent (E) is coated on a support and varies depending on the type of solvent, but is usually 50 to 150 ° C., preferably 60 to 100 ° C., usually 1 to 10 minutes. Preferably, the solvent is removed by drying for 2 to 7 minutes to form a coating film. The film thickness of the dried coating film is usually 5 to 75 μm, preferably 10 to 50 μm.
The pressure-sensitive adhesive layer preferably undergoes a crosslinking reaction under the following conditions. After apply | coating an adhesive composition on a support body and sticking a cover film on the coating film formed on the said conditions, it is 1 day or more normally, Preferably it is 1-10 days, Usually 5-60 degreeC, Preferably it is 15 It is cured in an environment of ˜40 ° C., usually 30 to 70% RH, preferably 40 to 70% RH. When crosslinking is performed under the aging conditions as described above, a crosslinked body (network polymer) can be efficiently formed.

  As a method for applying the pressure-sensitive adhesive composition, a known thickness such as a spin coating method, a knife coating method, a roll coating method, a bar coating method, a blade coating method, a die coating method, or a gravure coating method may be used. The method of applying and drying can be used.

  Examples of the support and cover film include polyester films such as polyethylene terephthalate (PET); and plastic films such as polyolefin films such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.

  The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive for optical members of the present invention preferably has a gel fraction of 50 to 100% by mass from the viewpoints of distortion suppression of the polarizing plate, cohesion, adhesion, and removability. Preferably it is 60-98 mass%, More preferably, it is 70-98 mass%.

The surface resistance value of the pressure-sensitive adhesive layer is preferably 1.0 × 10 ¹⁴ Ω / □ or less, more preferably 1.0 × 10 ¹³ Ω / □ or less, and particularly preferably 1.0 × 10 ⁵ to 1. 0.0 × 10 ¹² Ω / □. The surface resistance value indicates the electric resistance on the surface of the pressure-sensitive adhesive layer, and the smaller the value, the smaller the electric resistance and the better the antistatic performance. The surface resistance value can be measured by the method described in the examples.

  Since the pressure-sensitive adhesive for optical members of the present invention is formed from a pressure-sensitive adhesive composition having the above-described configuration, even under wet heat promotion conditions of 80 ° C./85% RH, which is stricter than 60 ° C./90% RH, Excellent durability.

(Optical laminate)
The optical layered body of the present invention has a pressure-sensitive adhesive layer formed from the above-mentioned pressure-sensitive adhesive for optical members. The pressure-sensitive adhesive layer is, for example, a double-sided pressure-sensitive adhesive sheet having only the pressure-sensitive adhesive layer, a base material, and a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed on both surfaces of the base material, the base material, and one of the base materials. The adhesive sheet is formed as a single-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed on the surface, and a pressure-sensitive adhesive sheet having a peel-treated cover film attached to the surface of the pressure-sensitive adhesive sheet that is not in contact with the base material.
Examples of the substrate and the cover film include polyester films such as polyethylene terephthalate (PET); and plastic films such as polyolefin films such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer.

The formation conditions and gel fraction of the pressure-sensitive adhesive layer are the same as the conditions described in the column (pressure-sensitive adhesive layer).
The film thickness of the pressure-sensitive adhesive layer to be formed is usually 5 to 75 μm, preferably 10 to 50 μm, from the viewpoint of maintaining the adhesive performance. Although the film thickness of a base material and a cover film is not specifically limited, Usually, 10-125 micrometers, Preferably it is 25-75 micrometers.

  The optical layered body of the present invention has a polarizing plate having a protective film on at least one surface, and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive for optical members of the present invention on the surface having the protective film of the polarizing plate. . In this specification, “polarizing plate” is used to include “polarizing film”.

A conventionally well-known polarizing plate can be used as a polarizing plate, For example, the polarizing plate which has a polarizer and the polarizer protective film arrange | positioned on the single side | surface or both surfaces of the said polarizer is mentioned.
As a polarizer, the stretched film obtained by making a film which consists of polyvinyl alcohol-type resins contain a polarizing component, and extending | stretching is mentioned, for example. Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, and a saponified product of an ethylene / vinyl acetate copolymer. Examples of the polarization component include iodine or a dichroic dye.

Examples of the polarizer protective film include films made of cellulose such as triacetylcellulose and acetylcellulose such as diacetylcellulose, polycarbonate films, polyethersulfone films, and polycycloolefin films. In the present invention, a cellulose film or a polycycloolefin film is used as the polarizer protective film, and even when the pressure-sensitive adhesive layer is formed in contact with the polarizer protective film, long-term reliability, specifically, moisture and heat resistance is improved. Excellent.
The thickness of the polarizing plate is usually 30 to 250 μm, preferably 50 to 200 μm.

  The method for forming the pressure-sensitive adhesive layer on the surface of the polarizing plate is not particularly limited. The method for applying the pressure-sensitive adhesive composition directly on the surface of the polarizing plate using a bar coater and drying and aging, the pressure-sensitive adhesive sheet for polarizing plate of the present invention There is a method in which the pressure-sensitive adhesive layer possessed by is transferred and aged on the surface of the polarizing plate. The conditions for drying and aging, the gel fraction, and the like are the same as the conditions described in the column (Adhesive layer).

The thickness of the pressure-sensitive adhesive layer formed on the polarizing plate is usually 5 to 75 μm, preferably 10 to 50 μm in terms of dry film thickness. In addition, the adhesive layer should just be formed in at least one surface of a polarizing plate, the aspect in which an adhesive layer is formed only in the single side | surface of a polarizing plate, the aspect in which an adhesive layer is formed in both surfaces of a polarizing plate Is mentioned.
Moreover, the layer which has other functions, such as a glare-proof layer, a phase difference layer, a viewing angle improvement layer, may be laminated | stacked on the said polarizing plate, for example.

  A liquid crystal element is produced by providing the polarizing plate with the pressure-sensitive adhesive layer of the present invention obtained as described above on the substrate surface of the liquid crystal cell. Here, the liquid crystal cell has a structure in which a liquid crystal layer is sandwiched between two substrates.

  For example, the polarizing plate has a polarizer and a protective film disposed on the polarizer, the pressure-sensitive adhesive layer formed from the polarizer, the protective film, and the pressure-sensitive adhesive for optical members of the present invention, and a glass substrate Can be manufactured in this order.

  As a board | substrate which a liquid crystal cell has, glass plates, such as an alkali free glass plate, are mentioned, for example. The thickness of the substrate is preferably 5 mm or less, and more preferably 0.05 to 2 mm.

  The optical layered body of the present invention includes an optical member having a cycloolefin polymer layer, and an optical member pressure-sensitive adhesive containing the (meth) acrylic polymer (A) of the first aspect on the cycloolefin polymer layer. It has a pressure-sensitive adhesive layer. Examples of the optical member having a cycloolefin polymer layer include a polarizing plate, a retardation film, and a polymer having a protective film made of the above-described cycloolefin polymer.

  By using the pressure-sensitive adhesive for optical members containing the (meth) acrylic polymer (A) of the first aspect of the present invention, it is possible to express better adhesion with the cycloolefin polymer layer, under a wet heat environment. Even in this case, the required performance can be exhibited in the workability and reworkability at the time of punching without causing floating or peeling.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. In the following description of Examples and the like, “part” means “part by mass” unless otherwise specified.

(Evaluation of hydrolytic properties of ionic compounds by triacetyl cellulose)
2 g of water and 2 g of an ionic compound were added to a polypropylene bottle to prepare a test solution having a concentration of 50% by mass. To this test solution, 0.25 g (thickness 40 μm, 40 mm × 120 mm) of triacetylcellulose film (TAC film; K-10 manufactured by Konica Minolta Co., Ltd.) was added and immersed. The polypropylene bottle was allowed to stand in an environment of 85 ° C. and 85% humidity for 300 hours, and then the test solution was collected and the acetic acid concentration in the solution was measured by high performance liquid column chromatography (manufactured by Shimadzu Corporation). ). The results are shown in Table 1.
The ionic compounds used in the above evaluation are as follows.

As shown in Table 1, in the ionic compound (C6), it is considered that hydrolysis of the TAC film progressed because the acetic acid concentration in the liquid was high. On the other hand, in the ionic compounds (C1) to (C5), since the concentration of acetic acid in the liquid is low, it is considered that the degree of hydrolysis of the TAC film is low. In particular, with the ionic compound (C1), the concentration of acetic acid in the liquid is further smaller than those of (C2) to (C5), and an excellent hydrolysis inhibiting action can be expected.

(GPC)
About the (meth) acrylic-type polymer (A), the weight average molecular weight (Mw) and the number average molecular weight (Mn) were calculated | required on condition of the following by the gel permeation chromatography method (GPC method).
-Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation)
-GPC column configuration: The following four columns (all manufactured by Tosoh Corporation)
(1) TSKgel HxL-H (guard column)
(2) TSKgel GMHxL
(3) TSKgel GMHxL
(4) TSKgel G2500HxL
・ Flow rate: 1.0 mL / min
-Column temperature: 40 ° C
Sample concentration: 1.5% (w / v) (diluted with tetrahydrofuran)
・ Mobile phase solvent: Tetrahydrofuran ・ Standard polystyrene conversion

(Synthesis Example A1)
In a reactor equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 99.4 parts of n-butyl acrylate, 0.5 part of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, and ethyl acetate solvent 100 parts were charged and heated to 80 ° C. while introducing nitrogen gas. Next, 0.1 part of 2,2′-azobisisobutyronitrile was added, and a polymerization reaction was performed at 80 ° C. for 6 hours in a nitrogen gas atmosphere. After completion of the reaction, the mixture was diluted with ethyl acetate to prepare a polymer solution having a solid content concentration of 25% by mass. Mw of obtained (meth) acrylic-type polymer A1 was 400,000, and Mw / Mn was 7.1.

(Synthesis Examples A2, A4 to A8, A10)
The polymerizable monomer used in the polymerization reaction was changed as described in Table 2, and the same procedure as in Synthesis Example A1 was carried out except that 80 parts of ethyl acetate solvent was added. (Meth) acrylic polymers A2 and A4 A polymer solution having a solid content concentration of 25% by mass containing ˜A8 and A10 was prepared. The results are shown in Table 2.

(Synthesis Examples A3 and A9)
The polymerizable monomer used in the polymerization reaction was changed as described in Table 2, and the same procedure as in Synthesis Example A1 was carried out except that 70 parts of ethyl acetate solvent was added. (Meth) acrylic polymers A3 and A9 A polymer solution having a solid content concentration of 25% by mass was prepared. The results are shown in Table 2.

Polymerizable monomer:
BA: n-butyl acrylate
MA: Methyl acrylate
MEA: Methoxyethyl acrylate
AA: Acrylic acid
2HEA: 2-hydroxyethyl acrylate
4HBA: 4-hydroxybutyl acrylate
AM: Acrylamide

Example 1
(1) Preparation of pressure-sensitive adhesive composition The (meth) acrylic polymer solution (solid content concentration 25% by mass) obtained in Synthesis Example A1 and the crosslinking agent (B) (B1): Nippon Polyurethane Industry Co., Ltd. “Coronate L” (solid content concentration: 75% by mass), (C2): 4-methyl-octylpyridinium / (FSO ₂ ) ₂ N ⁻ as ionic compound (C), and Shin-Etsu as silane coupling agent (D) A pressure-sensitive adhesive composition was obtained by mixing “KBM-403” manufactured by Chemical Industry Co., Ltd. In addition, the ratio of each component is (B1) 12 mass parts and (C2) 1.5 mass with respect to 100 mass parts of polymers A1 contained in the (meth) acrylic-type polymer solution obtained by the synthesis example A1. Part, (D) is an amount of 0.2 part by mass (both are solid content values).
(2) Preparation of pressure-sensitive adhesive sheet On the peeled polyethylene terephthalate film (PET film), the pressure-sensitive adhesive composition obtained in (1) above was applied at a liquid temperature of 25 ° C using a doctor blade, and at 90 ° C. The film was dried for 3 minutes to form a coating film having a dry film thickness of 20 μm. Two PET films were obtained by further laminating the peeled PET film on the surface of the coating film opposite to the surface on which the PET film was applied, and leaving it to stand for aging in a 23 ° C./50% RH environment for 7 days. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a thickness of 20 μm sandwiched between the layers was obtained.
(3) Production of pressure-sensitive adhesive-attached polarizing plate On the polyethylene terephthalate film (PET film) subjected to the release treatment, the pressure-sensitive adhesive composition obtained in the above (1) was applied at a liquid temperature of 25 ° C. using a doctor blade, It was dried at 90 ° C. for 3 minutes to obtain an adhesive sheet having a coating film having a dry film thickness of 20 μm. The pressure-sensitive adhesive sheet and the polarizing plate (thickness: 110 μm, layer structure: triacetyl cellulose film / polyvinyl alcohol film / triacetyl cellulose film) were bonded together so that the coating film and the polarizing plate were in contact with each other, and 23 ° C./50. A polarizing plate with a pressure-sensitive adhesive layer having a PET film, a pressure-sensitive adhesive layer having a thickness of 20 μm, and a polarizing plate was obtained by allowing to stand for 7 days under the condition of% RH and aging.

(Examples 2-7, 11-12, 15-16, Comparative Examples 1-3, 7-8)
In Example 1, the adhesive composition, the adhesive sheet, and the polarizing plate with an adhesive layer were obtained like Example 1 except having changed the compounding composition as described in Table 3 and Table 4.

(Examples 8 to 10, 12 to 14, 17 to 18, Comparative Examples 4 to 6, 9 to 10)
In Example 1, the composition was changed as described in Table 3 and Table 4, and in addition to the polarizing plate with the pressure-sensitive adhesive layer prepared in Example 1, the polarizing plate whose polarizer protective film is a cycloolefin film (Thickness: 110 μm, layer structure: COP film / polyvinyl alcohol film / COP film) A pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and a pressure-sensitive adhesive were the same as in Example 1 except that a polarizing plate with a pressure-sensitive adhesive layer was prepared. A polarizing plate with an agent layer was obtained.
In addition, each material of Table 3 is as showing below.
Cross-linking agent (B)
B1: Trimethylolpropane adduct of tolylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L, solid content concentration 75% by mass)
Ionic compound (C)
The same as the ionic compounds C1 to C6 used in the above (evaluation of ionic compounds).
Silane coupling agent (D)
D: Glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403)

(Evaluation)
(Gel fraction)
About 0.1 g of the pressure-sensitive adhesive layer was collected in a sampling bottle from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and 30 mL of ethyl acetate was added and shaken for 4 hours. The mixture was filtered through a metal mesh, the residue on the metal mesh was dried at 100 ° C. for 2 hours, and the dry weight was measured. The gel fraction of the pressure-sensitive adhesive layer was determined by the following formula.
Gel fraction (%) = (Dry weight / Adhesive layer sampling weight) × 100 (%)

(Surface resistance value)
The pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into a size of 100 mm × 100 mm to prepare test pieces. The PET film was peeled from the adhesive sheet, and the adhesive layer was sandwiched between circular front and back electrodes. A voltage of 100 V was applied, and the surface resistance value after 60 seconds was measured. In addition, the measurement was implemented by the double ring electrode method based on JISK6911 (1995), and the surface resistance value measurement used R8252 digital electrometer (made by ADC Co., Ltd.).

(Storage modulus G ')
The PET film was peeled off from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and the pressure-sensitive adhesive layer was laminated several times in a 23 ° C./50% RH environment, treated for 20 minutes in an autoclave at 50 ° C./5 atm, A pressure-sensitive adhesive layer having a thickness of 1.0 mm was produced. For the pressure-sensitive adhesive layer having a thickness of 1.0 mm, a dynamic viscoelasticity measurement method (temperature range: −40 to 160 ° C., temperature rising rate: 3.67 ° C.) based on JIS K7244 using “Physica MCR300” manufactured by Anton Paar. / Min, conditions of frequency 1 Hz), the viscoelastic spectrum was measured, and the storage elastic modulus at a temperature of 23 ° C. and 80 ° C. was determined.

(Mura)
The polarizing plate with the pressure-sensitive adhesive layer obtained in Examples / Comparative Examples is cut into a size of 80 mm × 140 mm, and a laminator so that absorption axes are orthogonal to each other on both sides of a 1.1 mm-thick alkali-free glass plate. It stuck using the roll, and it hold | maintained for 20 minutes in the autoclave adjusted to 50 degreeC and 5 atmospheres, and produced the test board. This test plate was allowed to stand for 72 hours at a temperature of 80 ° C., and light leakage was observed according to the following criteria.
A: Almost no light leakage was observed, and there was no problem in practical use. B: Slight light leakage was observed, but it could be used.

(Durability test)
A polarizing plate with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples (a laminate comprising PET film / pressure-sensitive adhesive layer / polarizing plate) was cut into a size of 150 mm × 250 mm to prepare a test piece. The PET film is peeled off from the test piece, and the pressure-sensitive adhesive layer and the non-alkali glass plate are brought into contact with one side of the 2 mm-thick non-alkali glass plate using a laminator roll. Stuck on. The obtained laminate was held in an autoclave adjusted to 50 ° C./5 atm for 20 minutes to prepare a test plate. Two similar test plates were prepared. The test plate was allowed to stand for 500 hours under conditions of a temperature of 80 ° C. (heat resistance) or a temperature of 80 ° C./85% humidity (humidity heat resistance). Appearance defects such as foaming from the pressure-sensitive adhesive layer of the test plate, cracks in the test plate, and peeling of the pressure-sensitive adhesive layer were visually observed and evaluated according to the following criteria.
(Standard)
A: Floating / peeling area less than 3% B: Floating / peeling area 3% or more and less than 5% C: Floating / peeling area 5% or more

Claims (6)

An adhesive for an optical member obtained from an acrylic polymer (A), a crosslinking agent (B), and an ionic compound (C),
As a monomer component constituting the acrylic polymer (A), (a2) 0.1 to 10% by weight of a carboxyl group-containing monomer is contained, and the crosslinking agent (B) is 100% by weight of the acrylic polymer (A). 4 to 30 parts by weight with respect to parts, and the ionic compound (C) is represented by a cation represented by the following chemical formula (1), a bis (fluorosulfonyl) imide anion, and a bis (trifluoromethylsulfonyl) imide anion. It is an ionic compound composed of selected anions, and the storage elastic modulus at 23 ° C. is 2.0 × 10 ⁵ Pa to 5.5 × 10 ⁶ Pa and the storage elastic modulus at 80 ° C. is 1.0 × 10 ⁵ Pa to An adhesive for optical members, which is 2.0 × 10 ⁶ Pa .
... (1)
In formula (1), R ¹¹ and R ¹² are each independently an alkyl group.
  The monomer component constituting the acrylic polymer (A) according to claim 1, wherein (a1-1) (meth) acrylic acid ester having a polyoxyalkylene group or an alkoxyalkyl group is 41 to 99.9% by weight. An adhesive for optical members, comprising:   The monomer component constituting the acrylic polymer (A) according to claim 1, wherein (a1-2) (meth) acrylic acid alkyl ester is contained in a proportion of 70 to 99.9% by weight. Adhesive for optical members.   An optical laminate comprising: a polarizing plate having a protective film on at least one surface; and an adhesive layer made of the adhesive for optical members according to claim 1 on the protective film. body.   The optical laminate according to claim 4, wherein the protective film is a cellulose film or a cycloolefin film.   An optical member having a cycloolefin polymer layer, and an optical layered body comprising the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive for optical members according to claim 2 laminated on the cycloolefin polymer layer.