JP6226684B2 - A pressure-sensitive adhesive for polarizing plates, a polarizing plate with a pressure-sensitive adhesive layer, an image display device, an active energy ray and / or a pressure-sensitive adhesive composition for thermosetting polarizing plates - Google Patents

Description

The present invention relates to a pressure-sensitive adhesive for polarizing plates (pressure-sensitive adhesive), a polarizing plate with a pressure-sensitive adhesive layer obtained by using the pressure-sensitive adhesive, an image display device, an active energy ray and / or a pressure-sensitive adhesive composition for a thermosetting polarizing plate . .
Specifically, the polarization fill beam that preferably used for a liquid crystal display equipment, in particular specifically, polarizing film, triacetate cellulose coated optical stack with a protective film such as a film and a glass substrate of the liquid crystal cell polarizer for adhesives used for bonding and, as well as about the pressure-sensitive adhesive layer-carrying polarizing plate in which a pressure-sensitive adhesive layer was formed consisting of the polarizer pressure-sensitive adhesive.

  Conventionally, a liquid crystal in which a polarizing plate in which both surfaces of a polyvinyl alcohol film and the like having a polarizing property are coated with a cellulose film, for example, a cellulose triacetate film, is sandwiched between two glass plates. Lamination on the surface of the cell to form a liquid crystal display panel is performed by laminating the pressure-sensitive adhesive layer provided on the surface of the polarizing plate against the liquid crystal cell surface and pressing it. It is normal.

  Such a polarizing plate has a three-layer structure in which both surfaces of a polyvinyl alcohol-based polarizer are sandwiched between triacetyl cellulose-based protective films, but dimensional stability is poor due to the characteristics of these materials. Moreover, since the polyvinyl alcohol-type polarizer is shape | molded by extending | stretching, the dimensional change with time is easy to occur. If the internal stress generated by such a dimensional change cannot be absorbed and relaxed, the distribution of residual stress acting on the polarizing plate becomes non-uniform, and stress is concentrated particularly on the peripheral portion of the polarizing plate. As a result, color unevenness / light leakage phenomenon occurs in the liquid crystal display device such that the peripheral edge of the liquid crystal display device is brighter or darker than the center.

  Therefore, for various optical applications, especially adhesives for attaching polarizing plates, research is being conducted to find adhesives that not only have excellent durability such as foaming and peeling, but also have excellent optical properties such as less light leakage. Has been done.

For example, Patent Document 1 discloses an acrylic resin (A), an aromatic compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated compound containing two or more ethylenically unsaturated groups ( The pressure-sensitive adhesive composition [I] containing C) is a pressure-sensitive adhesive that is cured by active energy rays and / or heat, and the content of the aromatic compound (B) is 100 weights of the acrylic resin (A). The content ratio (mol%) of the aromatic compound (B) with respect to the total amount of the aromatic compound (B) and the ethylenically unsaturated compound (C) is 3 to 300 parts by weight relative to 50 parts by weight. An adhesive characterized by being large is disclosed,
It can be suitably used as an optical member application, and the adhesive layer after curing by active energy rays and / or heat is excellent in handleability (tack) and optical properties (haze), and is used at high temperature and high humidity. Even in this environment, the optical laminate, especially the optical member such as a polarizing plate, and the glass substrate are excellent in adhesion, and no foaming or peeling occurs between the pressure-sensitive adhesive layer and the glass substrate, resulting in uneven color and light leakage. It is described that a liquid crystal display device that does not generate can be obtained.

JP 2011-168773 A

  However, in recent years, with respect to image quality required for image display devices, high definition and high contrast have been demanded, and accordingly, the polarizing plate constituting the image display device has an even higher level when subjected to a durability test. It is required to exhibit light leakage resistance. Further, in recent years, polarizing plates having a high viewing angle are often used. When such polarizing plates are used, light leakage resistance at a higher level is required. The technique of Document 1 still has room for improvement in terms of light leakage resistance.

Therefore, the present invention aims to provide a pressure-sensitive adhesive for a polarizing plate that exhibits excellent optical properties (particularly light leakage resistance) when the polarizing plate and a glass substrate are bonded together under such a background. .

However, as a result of intensive studies in view of such circumstances, the present inventor has obtained an acrylic resin (A), an ethylenically unsaturated compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated group. The pressure-sensitive adhesive composition [I] containing two or more ethylenically unsaturated compounds (C) contains one ethylenically unsaturated group in a pressure-sensitive adhesive that is cured by active energy rays and / or heat. As the ethylenically unsaturated compound (B), in addition to a conventionally used aromatic compound, a (meth) acrylate monomer containing a relatively long branched alkyl chain is used in combination , and (B), ( B1) and (B2) each content is a specific range, and by setting the content ratio of (B1) / (B2) to a specific range, it has been found that an adhesive having excellent light leakage resistance can be obtained. Completion It led to the cell.

That is, the gist of the present invention is an acrylic resin (A), an ethylenically unsaturated compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated group containing two or more ethylenically unsaturated groups. The pressure-sensitive adhesive composition [I] containing the compound (C) is a pressure-sensitive adhesive that is cured by active energy rays and / or heat, and contains an ethylenically unsaturated compound (B ) Contains an aromatic ring-containing monomer (B1) and a branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group, and is based on 100 parts by weight of the acrylic resin (A) The content of the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group is 10 to 80 parts by weight, and the content of the aromatic ring-containing monomer (B1) is 5 to 50 parts by weight. , Alkyl The branched alkyl chain-containing (meth) acrylate monomer (B2) having a carbon number of 14 or more is 5 to 50 parts by weight, and the aromatic ring-containing monomer (B1) and the alkyl group having a carbon number of 14 or more are branched. content of the alkyl chain-containing (meth) acrylate monomer (B2) (weight ratio), relates to a polarizing plate adhesive agent characterized (B1) / (B2) = 0.5 to 3 der Rukoto is there.
Furthermore, the pressure-sensitive adhesive layer-carrying polarizing plate comprising a laminated structure of the adhesive layer and the polarizing plate comprising an adhesive for the polarizing plate, and an image display device having such a polarizing plate.

Since the pressure-sensitive adhesive for polarizing plate of the present invention is excellent in adhesiveness between the polarizing plate and the glass substrate even in an environment of high temperature and high humidity, the pressure-sensitive adhesive layer after curing by active energy rays and / or heat, There can be obtained a liquid crystal display device in which foaming or peeling does not occur between the pressure-sensitive adhesive layer and the glass substrate, and no light leakage or color unevenness occurs.
In addition, the pressure-sensitive adhesive for polarizing plates is excellent in balance with durability and reworkability as well as light leakage resistance.
Hereinafter, “polarizing plate” is also referred to as “optical member”.

  In the case where the alkyl group of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group specified in the present invention is a linear alkyl group even if the carbon number is a long chain Is provided with releasability and it is difficult to sufficiently impart pressure-sensitive adhesive force. Even if it is a branched alkyl group, it has high volatility when the number of carbon atoms is short. Since the monomer is likely to volatilize, it has been found that the alkyl group specified in the present application exhibits an excellent effect.

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl is acrylic or methacrylic, (meth) acryloyl is acryloyl or methacryloyl, (meth) acrylate is acrylate or methacrylate, and acrylic resin is (meth) acrylic monomer. Each of the resins obtained by polymerizing a monomer component containing at least one kind of is meant.

First, the pressure-sensitive adhesive composition [I] of the present invention will be described.
The pressure-sensitive adhesive composition [I] of the present invention contains an acrylic resin (A), an ethylenically unsaturated compound (B) containing one ethylenically unsaturated group, and two or more ethylenically unsaturated groups. It contains an ethylenically unsaturated compound (C).

  The acrylic resin (A) used in the present invention comprises a (meth) acrylic acid alkyl ester monomer (a1) as a main component and, if necessary, a functional group-containing monomer (a2) as a copolymerization component. Furthermore, another copolymerizable monomer (a3) can be used as a copolymerization component. The acrylic resin (A) in the present invention uses the functional group-containing monomer (a2) as a copolymerization component, which becomes a cross-linking point of the acrylic resin (A), and the base resin or adherend. It is preferable at the point which raises adhesiveness further.

  As the (meth) acrylic acid alkyl ester monomer (a1), for example, the alkyl group usually has 1 to 20, particularly 1 to 12, more preferably 1 to 8, particularly 4 to 8 carbon atoms. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-propyl (meth) ) Acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate , Cyclohexyl (meth) acrylate, isobornyl (medium ) Acrylate, and the like. These may be used alone or in combination of two or more.

  Among such (meth) acrylic acid alkyl ester monomers (a1), n-butyl (meth) acrylate and 2-ethylhexyl (meth) are preferable in terms of copolymerizability, adhesive properties, ease of handling, and availability of raw materials. An acrylate is preferably used, and more preferably n-butyl (meth) acrylate is used in terms of excellent durability.

  The content in the case of copolymerizing the (meth) acrylic acid alkyl ester monomer (a1) is preferably 10 to 100% by weight, particularly preferably 50 to 99% by weight, more preferably, based on the entire copolymerization component. The content is preferably 80 to 98% by weight, and if the content of the (meth) acrylic acid ester monomer (a1) is too small, the adhesive performance tends to be lowered.

  Examples of the functional group-containing monomer (a2) include a monomer containing a functional group that can become a crosslinking point by reacting with a cross-linking agent (E) described later. Examples include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and an amino group-containing monomer. Monomers, acetoacetyl group-containing monomers, isocyanate group-containing monomers, glycidyl group-containing monomers and the like can be mentioned, and among these, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferably used in terms of efficient crosslinking reaction.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meta ) Acrylic acid hydroxyalkyl esters such as acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate and other caprolactone-modified monomers, diethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate and other oxyalkylene-modified monomers, and other 2-acrylic Primary hydroxyl group-containing monomers such as leuoxyethyl 2-hydroxyethylphthalic acid, N-methylol (meth) acrylamide, and hydroxyethyl acrylamide; Secondary hydroxyl group-containing monomers such as loxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro 2-hydroxypropyl (meth) acrylate; 2,2-dimethyl 2-hydroxyethyl (meth) acrylate and the like There may be mentioned tertiary hydroxyl group-containing monomers.

  Among the above hydroxyl group-containing monomers, a primary hydroxyl group-containing monomer is preferable from the viewpoint of excellent reactivity with a crosslinking agent, and a monomer having a hydroxyl group at the molecular chain end is considered preferable because it exhibits excellent antistatic performance. Furthermore, it is particularly preferable to use 2-hydroxyethyl acrylate because it has few impurities such as di (meth) acrylate and is easy to produce.

  In addition, as a hydroxyl-containing monomer used by this invention, it is also preferable to use a thing with the content rate of di (meth) acrylate which is an impurity 0.5% or less, and also 0.2% or less, especially 0 It is preferable to use one having a content of 1% or less, specifically 2-hydroxyethyl acrylate or 2-hydroxypropyl acrylate.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N-glycolic acid, and cinnamic acid. Among them, (meth) acrylic acid is preferably used.

  Examples of the amino group-containing monomer include t-butylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and the like.

  Examples of the acetoacetyl group-containing monomer include 2- (acetoacetoxy) ethyl (meth) acrylate and allyl acetoacetate.

  Examples of the isocyanate group-containing monomer include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and alkylene oxide adducts thereof.

Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate, allyl glycidyl (meth) acrylate, and the like.
These functional group-containing monomers (a2) may be used alone or in combination of two or more.

  The content in the case of copolymerizing the functional group-containing monomer (a2) is preferably 0 to 30% by weight, particularly preferably 0.1 to 10% by weight, more preferably 0, based on the entire copolymerization component. When the content of the functional group-containing monomer (a2) is too large, the viscosity tends to increase or the stability of the resin tends to decrease. In addition, when too small, there exists a tendency for durability performance to fall by cohesion force falling.

Other copolymerizable monomers (a3) include, for example, phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) ) Monomers containing one aromatic ring such as acrylate, styrene, α-methylstyrene; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxy Ethyl (meth) acrylate, 2-butoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (Meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, octoxypolyethyleneglycol-polypropyleneglycol-mono (meth) acrylate, lauroxypolyethyleneglycolmono (meth) acrylate, stearoxypolyethyleneglycolmono A monomer containing an alkoxy group such as (meth) acrylate and an oxyalkylene group;
Alkoxyalkyl such as methoxymethyl (meth) acrylamide, ethoxymethyl (meth) acrylamide, propoxymethyl (meth) acrylamide, isopropoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, isobutoxymethyl (meth) acrylamide ( (Meth) acrylamide monomers;
(Meth) acrylamide monomers such as (meth) acryloylmorpholine, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, (meth) acrylamide N-methylol (meth) acrylamide;
Acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, vinyl pyridine, vinyl pyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride , Methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethylallyl vinylketone and the like.
Moreover, you may copolymerize using the ethylenically unsaturated unsaturated compound (B) which contains one ethylenically unsaturated group mentioned later as another copolymerizable monomer (a3).

  The content in the case of copolymerizing the other copolymerizable monomer (a3) is preferably 0 to 30% by weight, particularly preferably 1 to 20% by weight, and more preferably 2%, based on the entire copolymerization component. When the content of the other copolymerizable monomer (a3) is too large, the effects of the present invention tend to be difficult to obtain.

  For the purpose of increasing the molecular weight, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate A compound having two or more ethylenically unsaturated groups such as divinylbenzene can also be used in combination.

  The acrylic resin (A) is produced by polymerizing the monomer components (a1) to (a3). For such polymerization, for example, solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc. The conventionally known polymerization method can be employed, and the polymerization conditions may be polymerized according to conventionally known general polymerization conditions.

  For example, in an organic solvent, a polymerization monomer such as (meth) acrylic acid alkyl ester monomer (a1), functional group-containing monomer (a2), other copolymerizable monomer (a3), polymerization initiator (azobisisobutyrate) (Ronitrile, azobisisovaleronitrile, benzoyl peroxide, etc.) may be mixed or added dropwise, and radical polymerization may be carried out for 2 to 20 hours under reflux conditions or at 50 to 90 ° C.

  Examples of the organic solvent used for the polymerization include aromatic hydrocarbons such as toluene and xylene, esters such as methyl acetate, ethyl acetate and butyl acetate, aliphatic alcohols such as n-propyl alcohol and isopropyl alcohol, acetone, Examples include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

  Examples of the polymerization initiator used for such radical copolymerization include azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, which are ordinary radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, Specific examples thereof include peroxide polymerization initiators such as -t-butyl peroxide and cumene hydroperoxide.

  The weight average molecular weight of the acrylic resin (A) is usually 100,000 to 3,000,000, preferably 500,000 to 2,200,000, particularly preferably 800,000 to 1,800,000, and particularly preferably 1,000,000 to 1,600,000. When the weight average molecular weight is too small, the durability performance tends to be lowered. When the weight average molecular weight is too large, a large amount of a diluent solvent is required, which tends to be undesirable in terms of coating property and cost.

  The degree of dispersion (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 20 or less, particularly preferably 10 or less, more preferably 7 or less, and particularly preferably 4 or less. preferable. When the degree of dispersion is too high, the durability performance of the pressure-sensitive adhesive layer is lowered, and foaming or the like tends to occur. The lower limit of the degree of dispersion is usually 1.1 from the viewpoint of production limit.

  Furthermore, the glass transition temperature of the acrylic resin (A) is preferably −80 to 0 ° C., particularly preferably −75 to −10 ° C., more preferably −60 to −20 ° C. If the glass transition temperature is too high. There exists a tendency for adhesive force to rise too much, and when too low, there exists a tendency for heat resistance to fall.

Ｔg：共重合体のガラス転移温度（Ｋ）
Ｔga：モノマーＡのホモポリマーのガラス転移温度（Ｋ） Ｗa：モノマーＡの重量分率
Ｔgb：モノマーＢのホモポリマーのガラス転移温度（Ｋ） Ｗb：モノマーＢの重量分率
Ｔgn：モノマーＮのホモポリマーのガラス転移温度（Ｋ） Ｗn：モノマーＮの重量分率
（Ｗa＋Ｗb＋・・・＋Ｗn＝１） In addition, said weight average molecular weight is a weight average molecular weight by standard polystyrene molecular weight conversion, and it is a column in high performance liquid chromatography (The Japan Waters company "Waters 2695 (main body)" and "Waters 2414 (detector)"). : Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler The particle diameter is measured by using three series of 10 μm), and the same method can be used for the number average molecular weight. The degree of dispersion is determined from the weight average molecular weight and the number average molecular weight. The glass transition temperature is calculated from the following Fox equation.

Tg: Glass transition temperature of copolymer (K)
Tga: Glass transition temperature of monomer A homopolymer (K) Wa: Weight fraction of monomer A Tgb: Glass transition temperature of homopolymer of monomer B (K) Wb: Weight fraction of monomer B Tgn: Homogeneity of monomer N Glass transition temperature of polymer (K) Wn: weight fraction of monomer N (Wa + Wb +... + Wn = 1)

As the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group used in the present invention (hereinafter sometimes abbreviated as “monofunctional monomer (B)”),
It is necessary to contain the aromatic ring-containing monomer (B1) and the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group.

Examples of the ethylenically unsaturated group of the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group include a (meth) acryloyl group, a crotonoyl group, a vinyl group, and an allyl group. It is active that the ethylenically unsaturated compound (B) containing one unsaturated group is a compound containing a (meth) acryloyl group in its structure, that is, a mono (meth) acrylate compound. This is preferable in that the reaction easily proceeds when cured by energy rays and / or heat.

As said aromatic ring containing monomer (B1), what is necessary is just a compound which has an aromatic ring and one ethylenically unsaturated group in a molecule | numerator, As a functional group containing this ethylenically unsaturated group, (meth) acryloyl is mentioned. Group, crotonoyl group, vinyl group, allyl group and the like.
In addition, the number of aromatic rings contained in the aromatic ring-containing monomer (B1) may be one or a plurality of aromatic rings, but one aromatic ring may be included in order to balance the adhesive properties. A compound containing two aromatic rings is preferable from the viewpoint of efficiently controlling the refractive index and birefringence of the pressure-sensitive adhesive layer.

  Specific examples of the aromatic ring-containing monomer (B1) include ether-based monofunctional aromatic compounds (b1), ester-based monofunctional aromatic compounds (b2), benzyl (meth) acrylate, and styrene. Examples of the ether-based monofunctional aromatic compound (b1) include dihydroxybenzene derivatives such as phenol derivatives, catechol, resorcinol, hydroquinone, and the like, and ester-based monofunctional aromatic compounds (b2). Examples thereof include benzoic acid derivatives and phthalic acid derivatives.

The phenol derivative is preferably a derivative (b1-1) having a structure in which the hydrogen atom of the hydroxyl group of phenol is replaced with a structural site containing a (meth) acryloyl group. As the dihydroxybenzene derivative, the resorcinol has 2 A derivative (b1-2) in which one or both hydrogen atoms of one hydroxyl group are replaced with a structural site containing a (meth) acryloyl group is preferable.
As the structural moiety containing such a (meth) acryloyl group, those represented by the following general formula (1) also containing an oxyalkylene structure are preferable.

（式中、Ｒは水素原子またはメチル基、Ｘはアルキレン基、ｎは１以上の整数である。）

(In the formula, R is a hydrogen atom or a methyl group, X is an alkylene group, and n is an integer of 1 or more.)

X in the above general formula (1) is an alkylene group, among which an alkylene group having 1 to 10 carbon atoms is preferable, and in particular, an alkylene group having 1 to 4 carbon atoms such as an ethylene group, a propylene group, or a tetramethylene group. Groups are preferred, especially ethylene groups.
When n is a polyoxyalkylene chain moiety having 2 or more, a homopolymer of the same oxyalkylene chain may be used, or different oxyalkylene chains may be copolymerized randomly or in a block form.
The alkylene group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group, an amino group, a sulfanyl group, an aryl group, and a heteroaryl group. Of these, a hydroxyl group is preferred.

  N in the general formula (1) is an integer of 1 or more, preferably 1 to 10, particularly preferably 1 to 2, and further preferably 2. If the value of n is too large, the heat and humidity resistance of the acrylic resin tends to decrease, and in order to control the refractive index and birefringence, shorter alkylene groups and oxyalkylene structures are preferable, so n is small. It is preferable.

Specific examples of the above (b1-1) include, for example, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, phenoxypropyl (meth) acrylate, and phenoxydipropylene glycol (meth). Acrylate, phenoxypolypropylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, ethoxylated phenylphenyl (meth) acrylate, and the like, and as commercially available products, phenoxypolyethylene glycol acrylate (Osaka Organic Chemical Co., Ltd.) Product name “Biscoat # 193”), 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., product name “Biscoat # 220”) , Phenoxydiethylene glycol acrylate (manufactured by Kyoei Co., Ltd., trade name “light acrylate P2HA”), ethoxylated o-phenylphenol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester A-LEN-10”), ethoxylated p-phenylphenol Acrylate (made by Shin-Nakamura Chemical Co., Ltd., trade name “NK ester POB-A”)
Etc.

The benzoic acid derivative is preferably a derivative (b2-1) having a structure in which the hydrogen atom of the carboxyl group of benzoic acid is replaced with a structural site containing a (meth) acryloyl group. It is preferably a derivative (b2-2) having a structure in which one or both hydrogen atoms of the two carboxyl groups of the acid are replaced with a structural site containing a (meth) acryloyl group.
As the structural moiety containing such a (meth) acryloyl group, those represented by the general formula (1) described above are preferable.

  Specific examples of the derivative (b2-2) include commercially available products such as 2-acryloyloxyethyl-2-hydroxypropyl phthalate (trade name “Biscoat # 2311HP” manufactured by Osaka Organic Chemical Co., Ltd.), 2-acryloyloxy. Ethyl hydrogen phthalate (trade name “Biscoat # 2000” manufactured by Osaka Organic Chemical Co., Ltd.), 2-acryloyloxypropyl hydrogen phthalate (trade name “Biscoat # 2100” manufactured by Osaka Organic Chemical Co., Ltd.), 2-methacryloyloxyethyl phthalic acid (Manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “CB-1”).

  Examples of the aromatic ring-containing monomer (B1) other than the above include phenylthio structure-containing (meth) acrylate compounds, naphthalene structure-containing (meth) acrylate compounds, and bromophenyl structure-containing (meth) acrylate compounds.

Examples of the phenylthio structure-containing (meth) acrylate compound include phenylthio (meth) acrylate, phenylthioalkyl (meth) acrylate, and the like, and the phenylthioalkyl (meth) acrylate has a carbon number of an alkyl group. 1 to 12 phenylthioalkyl (meth) acrylates, specifically, phenylthiomethyl (meth) acrylate, phenylthioethyl (meth) acrylate, phenylthiopropyl (meth) acrylate, phenylthiobutyl (meth) Acrylate, phenylthiopentyl (meth) acrylate, phenylthiohexyl (meth) acrylate, phenylthioheptyl (meth) acrylate, phenylthiooctyl (meth) acrylate, phenylthiononyl (meth) Acrylate, and phenylthio decyl (meth) acrylate.
Among these, phenylthioalkyl (meth) acrylate is preferable, phenylthioethyl (meth) acrylate is particularly preferable in terms of efficiently giving a positive photoelastic effect, and phenylthioethyl acrylate is more preferable.

  Examples of the naphthalene structure-containing (meth) acrylate compound include naphthoxy (meth) acrylate, naphthoxymethyl (meth) acrylate, naphthoxyethyl (meth) acrylate, naphthoxypropyl (meth) acrylate, and the like.

Examples of the bromophenyl structure-containing (meth) acrylate include bromophenoxymethyl (meth) acrylate, dibromophenoxymethyl (meth) acrylate, tribromophenoxymethyl (meth) acrylate, tetrabromophenoxymethyl (meth) acrylate, and pentabromo Phenoxymethyl (meth) acrylate, bromophenoxyethyl (meth) acrylate, dibromophenoxyethyl (meth) acrylate, tribromophenoxyethyl (meth) acrylate, tetrabromophenoxyethyl (meth) acrylate, pentabromophenoxyethyl (meth) acrylate, Bromophenoxypropyl (meth) acrylate, dibromophenoxypropyl (meth) acrylate, tribromophenoxypropyl ( Data) acrylate, tetrabromo-phenoxypropyl (meth) acrylate, penta-bromo-phenoxypropyl (meth) phenoxyalkyl (meth) acrylate benzene ring is substituted with 1-5 bromine atoms, such as acrylate.
In addition, carbon number of this alkyl group is 1-12 normally.

  Among these, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxydipropylene glycol (meth) acrylate, phenoxypolypropylene glycol (meth) acrylate, 2-Hydroxy-3-phenoxypropyl (meth) acrylate and ethoxylated phenylphenyl (meth) acrylate are preferred. Examples of commercially available products include phenoxypolyethylene glycol acrylate (trade name “Biscoat # 193” manufactured by Osaka Organic Chemical Co., Ltd.). 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., trade name “Biscoat # 220”), phenoxy diethyl Glycol acrylate (manufactured by Kyoeisha, trade name “light acrylate P2HA”), ethoxylated o-phenylphenol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester A-LEN-10”), ethoxylated p-phenylphenol acrylate (Made by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester POB-A”) is preferable, and ethoxylated o-phenylphenol acrylate and ethoxylated are particularly preferable in terms of reworkability with the adherend and good durability. p-phenylphenol acrylate and phenoxydiethylene glycol acrylate.

  The weight average molecular weight of the aromatic ring-containing monomer (B1) is usually 200 to 10,000, preferably 220 to 1,000, and particularly preferably 250 to 500. If the weight average molecular weight is too large, the birefringence tends to be difficult to adjust due to a decrease in the aromatic ring concentration.If the weight average molecular weight is too small, it tends to volatilize when the pressure-sensitive adhesive is dried, and the effect of the invention tends to be difficult to obtain. is there.

The number of carbon atoms of the branched alkyl group of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is required to be 14 or more, preferably 14 to 30, particularly Preferably it is 16-24, More preferably, it is 16-18.
If the number of carbon atoms is too large, the adhesive strength tends to decrease.

  Specific examples of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group include isotetradecyl (meth) acrylate (carbon number 14), isopentadecyl (meth) acrylate ( 15 carbon atoms, isohexadecyl (meth) acrylate (16 carbon atoms), isoheptadecyl (meth) acrylate (17 carbon atoms), isooctadecyl (meth) acrylate (18 carbon atoms), isononadecyl (meth) acrylate (19 carbon atoms) ), Isoicosane (meth) acrylate (carbon number 20), isotetracosane (meth) acrylate (carbon number 24), and the like.

  Among these, isooctadecyl (isostearyl) acrylate, isoicosane acrylate, and isotetracosane acrylate are preferable, and isooctadecyl acrylate is particularly preferable in terms of excellent light leakage resistance.

  The weight average molecular weight of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is usually 200 to 10,000, preferably 220 to 1,000, particularly preferably 250 to 500. It is. When the weight average molecular weight is too large, the unsaturated group concentration is lowered, so that the reactivity is lowered and the crosslinking density tends to be lowered. If it is too small, it tends to volatilize when the adhesive is dried, and the effect of the invention tends to be difficult to obtain.

The content of ethylenically unsaturated compounds containing one ethylenically unsaturated group (B), per 100 parts by weight of the acrylic resin (A), the Ri 10-80 parts by der, is good Mashiku 20 to 80 parts by weight, preferably 30 to 80 parts by weight, especially, the more preferably 35 to 80 parts by weight. When the content of the monofunctional aromatic compound (B) is too large, the durability tends to decrease, and when it is too small, the light leakage resistance tends to decrease.

The content of the aromatic ring-containing monomer (B1) is, relative to 100 parts by weight of the acrylic resin (A),. 5 to Ri 50 parts by der, good Mashiku is 10-50 parts by weight, the preferred especially 15 50 parts by weight. When there is too much content of an aromatic ring containing monomer (B1), there exists a tendency for durability to fall easily, and when there is too little, there exists a tendency for light leakage resistance to fall.

The content of carbon atoms in the alkyl group 14 or more branched alkyl chain containing (meth) acrylate monomer (B2) is an acrylic resin (A) with respect to 100 parts by weight, Ri 5-50 parts by der, good the Mashiku 10-50 parts by weight, the preferred especially from 15 to 50 parts by weight. When the content of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is too large, the durability tends to decrease, and when it is too small, the light leakage resistance is decreased. Tend.

The content ratio (weight ratio) of the aromatic ring-containing monomer (B1) and the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is (B1) / (B2) = 0.5. 1-3 der is, the good Mashiku (B1) / (B2) = 0.5~2, preferably especially a (B1) / (B2) = 0.5~1.
The light leakage resistance tends to decrease if the content of the aromatic ring-containing monomer (B1) is too large or too small relative to the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group. is there.

  Examples of the ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups used in the present invention (hereinafter sometimes abbreviated as “polyfunctional unsaturated compound (C)”) include: Ethylenically unsaturated monomer containing two or more ethylenically unsaturated groups in one molecule, for example, bifunctional monomer, trifunctional or more monomer, urethane (meth) acrylate compound, epoxy (meth) acrylate compound Polyester (meth) acrylate compounds can be used. Among these, it is preferable to use an ethylenically unsaturated monomer and a urethane (meth) acrylate-based compound from the viewpoint of excellent curing rate and ultimate physical properties.

  The bifunctional monomer may be any monomer containing two ethylenically unsaturated groups. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene Oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate 1,6-hexanediol ethylene oxide modified di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di ( (Meth) acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, 2- (meth) acryloyloxyethyl acid phosphate diester It is done.

  The tri- or higher functional monomer may be any monomer containing three or more ethylenically unsaturated groups. For example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) Acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, Glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ethylene oxide modified dipentaerythritol (Meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, succinic acid modified pentaerythritol tri (meth) acrylate Etc.

  The urethane (meth) acrylate compound is a (meth) acrylate compound having a urethane bond in the molecule, a (meth) acrylic compound containing a hydroxyl group and a polyvalent isocyanate compound (if necessary, a polyol What is necessary is just to use what is obtained by making it react by a well-known general method, and what is necessary is just to use the thing of 300-4,000 normally as the weight average molecular weight.

  Among these, tetraethylene glycol di (meth) acrylate, trimethylolpropane tri (meta) are easily compatible with resins, are easily available, and are easy to adjust crosslink density (easy to balance adhesion and durability). ) Acrylate is preferred.

  The content of the polyfunctional unsaturated compound (C) is desirably 0.01 to 100 parts by weight, preferably 0.5 to 20 parts by weight, with respect to 100 parts by weight of the acrylic resin (A). More preferably, it is 1 to 5 parts by weight. If the content of the polyfunctional unsaturated compound (C) is too large, the pressure-sensitive adhesive layer tends to be too hard and tends to float or peel off. If it is too small, the cohesive force of the pressure-sensitive adhesive layer is insufficient. Foaming tends to occur.

  In the present invention, the monofunctional monomer (B) and the polyfunctional monomer can be used in that the crosslinking density is appropriate, the tackiness can be appropriately adjusted, and the durability can be balanced. The content ratio (mol%) of the monofunctional monomer (B) with respect to the total amount of the unsaturated compound (C) is preferably larger than 50 mol%, particularly preferably larger than 50 mol% and smaller than 100 mol%, particularly preferably 55. It is -99 mol%, More preferably, it is 60-98 mol%, Most preferably, it is 65-97 mol%.

  When the content ratio of the monofunctional monomer (B) to the total amount of the monofunctional monomer (B) and the polyfunctional unsaturated compound (C) is too small, the polyfunctional unsaturated compound with respect to the monofunctional monomer (B) Since the content of (C) increases, the crosslinking density tends to be too high and the tackiness tends to be lacking. In addition, when the content ratio of the monofunctional monomer (B) with respect to the total amount of the monofunctional monomer (B) and the polyfunctional unsaturated compound (C) is too large, the polyfunctionality with respect to the monofunctional monomer (B) may be reduced. Since the content of the saturated compound (C) decreases, the crosslinking density does not increase so much and the durability tends to decrease.

In the present invention, the pressure-sensitive adhesive composition [I] containing the acrylic resin (A), the monofunctional monomer (B), and the polyfunctional unsaturated compound (C) as essential components includes active energy rays and The present invention provides a pressure-sensitive adhesive that is cured by heat (irradiation with active energy rays and / or heating). In such curing, the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C) are polymerized (polymerized) by active energy rays and / or heat and cured.
When the acrylic resin (A) is involved in the reaction, it is not limited to the polymerization of the monofunctional monomer (B) and the polyfunctional unsaturated compound (C) by active energy rays and / or heat, Curing associated with polymerization of the unsaturated group-containing acrylic resin (A), the monofunctional aromatic compound (B), and the polyfunctional unsaturated compound (C) will also occur.

  When curing with the active energy ray and / or heat, the pressure-sensitive adhesive composition [I] further contains a polymerization initiator (D) at the time of active energy ray irradiation and / or heating. It is preferable at the point which can stabilize reaction.

  Moreover, in this invention, in addition to said (A)-(C) component or (A)-(D) component as a method of hardening | curing the said adhesive composition [I], a crosslinking agent (E) is further added. There is also a method in which the pressure-sensitive adhesive composition [I] is cured with active energy rays and / or heat and cured with a crosslinking agent. In addition, when using a crosslinking agent (E), it is preferable that acrylic resin (A) has a functional group, and hardening (crosslinking) is performed by this functional group and a crosslinking agent reacting.

  In the present invention, the above-described curing by active energy rays and / or heat (irradiation of active energy rays and / or heating) is preferable in that it can be cured by irradiation of active energy rays such as ultraviolet rays for a very short time. However, it is also preferable to use curing (crosslinking) with a cross-linking agent in combination, and the cross-linking density of the pressure-sensitive adhesive is increased, the cohesive force is increased, and a further superior durability can be obtained.

  As the polymerization initiator (D), for example, various polymerization initiators such as a photopolymerization initiator (d1) and a thermal polymerization initiator (d2) can be used. It is preferable to use d1) in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  Further, when the photopolymerization initiator (d1) is used, the acrylic resin composition is cured by irradiation with active energy rays, and when the thermal polymerization initiator (d2) is used, the acrylic resin composition is cured by heating. However, it is also preferable to use both in combination as necessary.

  Examples of the photopolymerization initiator (d1) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Ben such as ether Ins; benzophenone, methylbenzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) ) Benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) ) Benzophenones such as trimethylammonium chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino) Thioxanthones such as 2-hydroxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2 , 4,4-trimethyl-pentylphosphine oxide, acyl phosphooxides such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; In addition, these photoinitiators (d1) may be used independently and may use 2 or more types together.

  These auxiliary agents include triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylaminobenzoic acid. Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone Etc. can be used in combination.

  Among these, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1- It is preferable to use phenylpropan-1-one.

  Examples of the thermal polymerization initiator (d2) include methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetyl acetate peroxide, 1,1-bis (t-hexyl peroxide). ) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1, 1-bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1- Bis (t-butylperoxy) butane, 2,2-bis (4 -Di-t-butylperoxycyclohexyl) propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroper Oxide, t-butyl hydroperoxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-Butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexa Noyl peroxide, octanoyl per Oxide, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoyl benzoyl peroxide, benzoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butyl) (Cyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-s-butyl peroxydicarbonate, Di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-te Lamethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxy Pivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylper) Oxy) hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t- Hexyl peroxyisopropyl monocarbonate, t-butyl peroxyisobutyrate t-butyl peroxymalate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2 -Ethylhexyl monocarbonate, t-butyl peroxyacetate, t-butyl peroxy-m-toluylbenzoate, t-butyl peroxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5 -Bis (m-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilylper Oxide, 3,3 ', 4,4'-tetra Organic peroxide initiators such as (t-butylperoxycarbonyl) benzophenone and 2,3-dimethyl-2,3-diphenylbutane; 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1- [(1-cyano-1-methylethyl) azo] formamide, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′- Azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis (2-methyl- N-phenylpropionamidine) dihydrochloride, 2,2'-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] Hydride chloride, 2,2'-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride 2,2'-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2,2'-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) Lopan] dihydrochloride, 2,2'-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (5-hydroxy-3 , 4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] ] Propionamide], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide], 2,2'-azobis [2-me Til-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropionamide), 2,2'-azobis (2,4,4-trimethylpentane), 2,2'- Azobis (2-methylpropane), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl ) Propionitrile] and the like; and the like. In addition, these thermal polymerization initiators may be used independently and may use 2 or more types together.

  About content of the said polymerization initiator (D), it is 0.1-50 weight part with respect to a total of 100 weight part of the said monofunctional compound (B) and polyfunctional unsaturated compound (C). Is preferably 0.5 to 30 parts by weight, more preferably 1 to 10 parts by weight. If the content of the polymerization initiator (D) is too small, the curability tends to be poor and the physical properties tend to become unstable, and if it is too much, no further effect can be obtained.

  In the active energy ray irradiation, far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays and other electromagnetic waves, X rays, γ rays and other electromagnetic waves, as well as electron beams, proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous from the standpoint of availability of the device and price. In addition, when performing electron beam irradiation, it can harden | cure without using the said photoinitiator (d1).

As a light source for the ultraviolet irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, or the like is used. In the case of the high-pressure mercury lamp, for example, it is performed under conditions of 5 to 3000 mJ / cm ² , preferably 10 to 1000 mJ / cm ² . Moreover, in the case of the said electrodeless lamp, it is performed on the conditions of 2-1500 mJ / cm < ² >, for example, Preferably 5-500 mJ / cm < ² >. The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but may be usually from several seconds to several tens of seconds, and in some cases, may be a fraction of a second. On the other hand, in the case of the electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 Kev is used, and the irradiation amount is preferably 2 to 50 Mrad.

  Moreover, when using a thermal-polymerization initiator (d2) as said polymerization initiator (D), a polymerization reaction is started and advanced by heating. The treatment temperature and treatment time at the time of curing by heating vary depending on the type of the thermal polymerization initiator (d2) to be used, and are usually calculated from the half-life of the initiator, but the treatment temperature is usually The temperature is preferably 70 ° C to 170 ° C, and the treatment time is usually preferably 0.2 to 20 minutes, and particularly preferably 0.5 to 10 minutes.

  Examples of the crosslinking agent (E) include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, aldehyde crosslinking agents, amine crosslinking agents, and metal chelate crosslinking agents. Among these, an isocyanate-based crosslinking agent is preferably used because it is easy to suppress durability and light leakage.

  Examples of the isocyanate crosslinking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and hexamethylene. Diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and polyisocyanate compounds thereof And adducts of a polyol compound such as trimethylolpropane, and burettes and isocyanurates of these polyisocyanate compounds.

  Examples of the epoxy crosslinking agent include bisphenol A / epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol diglycidyl ether. , Trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether and the like.

  Examples of the aziridine-based crosslinking agent include tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4. '-Bis (1-aziridinecarboxamide), N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) and the like can be mentioned.

  Examples of the melamine-based crosslinking agent include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexaptoxymethyl melamine, hexapentyloxymethyl melamine, hexahexyloxymethyl melamine, and melamine resin. .

  Examples of the aldehyde-based crosslinking agent include glyoxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardialdehyde, formaldehyde, acetaldehyde, benzaldehyde and the like.

  Examples of the amine-based crosslinking agent include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetraamine, diethylenetriamine, triethyltetraamine, isophoronediamine, amino resin, polyamide, and the like.

  Examples of the metal chelate-based crosslinking agent include acetylacetone and acetoacetyl ester coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, panadium, chromium, and zirconium. Can be mentioned.

  Moreover, these crosslinking agents (E) may be used independently and may use 2 or more types together.

  Usually, the content of the crosslinking agent (E) is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 15 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Particularly preferred is 0.1 to 10 parts by weight. When the amount of the crosslinking agent (E) is too small, there is a tendency that the cohesive force is insufficient and sufficient durability cannot be obtained. When the amount is too large, the flexibility and the adhesive strength are lowered, the durability is lowered, and peeling is caused. Since it tends to occur, the use as an optical member tends to be difficult.

  In the present invention, it is preferable to further contain a silane coupling agent (F) as a constituent component of the pressure-sensitive adhesive composition [I] from the viewpoint of improving the adhesion to the optical member.

  Examples of the silane coupling agent (F) include an epoxy group-containing silane coupling agent, a (meth) acryloyl group-containing silane coupling agent, a mercapto group-containing silane coupling agent, a hydroxyl group-containing silane coupling agent, and a carboxyl group-containing. Examples thereof include a silane coupling agent, an amino group-containing silane coupling agent, an amide group-containing silane coupling agent, and an isocyanate group-containing silane coupling agent. These may be used alone or in combination of two or more. Among these, an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent are preferably used, and the combined use of an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent also improves wet heat durability. It is preferable in that the adhesive strength does not increase too much.

  Specific examples of the epoxy group-containing silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycol. Sidoxypropylmethyldimethoxysilane, methyltri (glycidyl) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like can be mentioned. γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

  Specific examples of the mercapto group-containing silane coupling agent include, for example, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane, or oligomer type silane coupling of these compounds. Agents and the like.

  The content of the silane coupling agent (F) is usually 0.001 to 10 parts by weight, preferably 0.01 to 1 part by weight, particularly preferably 100 parts by weight of the acrylic resin (A). Is 0.03 to 0.8 parts by weight. If the content of the silane coupling agent (F) is too small, there is a tendency that the addition effect cannot be obtained. If the content is too large, the compatibility with the acrylic resin (A) is lowered, and adhesive strength and cohesive strength are obtained. There is a tendency to disappear.

The pressure-sensitive adhesive composition [I] further includes an antistatic agent, other acrylic pressure-sensitive adhesives, other pressure-sensitive adhesives, urethane resin, rosin, rosin ester, and hydrogenated rosin as long as the effects of the present invention are not impaired. Tackifiers such as esters, phenol resins, aromatic modified terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, styrene resins, xylene resins, colorants, fillers, anti-aging agents, UV absorbers Conventionally known additives such as functional dyes, and compounds that cause coloration or discoloration by irradiation with ultraviolet rays or radiation can be blended.
In addition to the above additives, a small amount of impurities contained in the raw materials for producing the constituent components of the pressure-sensitive adhesive composition [I] may be contained.

  Examples of the antistatic agent include cationic antistatic agents of quaternary ammonium salts such as imidazolium salts and tetraalkylammonium sulfonates, aliphatic sulfonates, higher alcohol sulfates, and higher alcohol alkylene oxide additions. Anion-type antistatic agents such as sulfuric acid ester salts, higher alcohol phosphate salts, higher alcohol alcohol alkylene oxide adduct phosphate salts, potassium bis (fluorosulfonyl) imide, lithium bis (trifluorosulfonyl) imide and lithium chloride And alkali metal salts such as alkaline earth metal salts, higher alcohol alkylene oxide adducts, and polyalkylene glycol fatty acid esters.

  Thus, in the present invention, a pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition [I] is obtained.

  And the optical member with an adhesive layer can be obtained by carrying out the lamination formation of the adhesive layer which consists of the said adhesive on an optical member (optical laminated body).

  It is preferable that the optical member with the pressure-sensitive adhesive layer is further provided with a release sheet on the surface opposite to the optical member surface of the pressure-sensitive adhesive layer.

  As the method for producing the optical member with the pressure-sensitive adhesive layer, when the pressure-sensitive adhesive composition [I] is cured by at least one of active energy ray irradiation and heating, [1] the pressure-sensitive adhesive composition on the optical member After applying and drying the product [I], a release sheet is bonded, and the treatment is performed by at least one of active energy ray irradiation and heating, [2] the pressure-sensitive adhesive composition [I] on the release sheet After applying and drying, a method of pasting the optical member and performing treatment by at least one of active energy ray irradiation and heating, [3] applying and drying the adhesive composition [I] on the optical member, A method of pasting a release sheet after performing treatment by at least one of irradiation with active energy rays and heating, [4] coating and drying the adhesive composition [I] on the release sheet, and further active energy rays After performing the morphism and at least one by treatment with heating, and a method of bonding an optical member. Among these, the case of performing active energy ray irradiation by the method [2] is preferable from the viewpoint of not damaging the substrate, workability and stable production.

  In addition, when a crosslinking agent is used for the pressure-sensitive adhesive composition [I] (when curing with a crosslinking agent (crosslinking) is also used), an aging treatment is performed after the optical member with the pressure-sensitive adhesive layer is produced using the above method. It is preferable to apply. This aging treatment is performed to balance the physical properties of the adhesive as the reaction time of the chemical crosslinking of the adhesive. As the aging conditions, the temperature is usually from room temperature to 70 ° C., and the time is usually from 1 day to 30 days. Specifically, for example, the treatment may be performed under conditions such as 23 ° C. for 1 day to 20 days, 23 ° C. for 3 to 10 days, 40 ° C. for 1 day to 7 days, and the like.

  In applying the pressure-sensitive adhesive composition [I], the pressure-sensitive adhesive composition [I] is preferably diluted with a solvent, and the diluted concentration is preferably 5 to 60 wt. %, Particularly preferably 10 to 30% by weight. The solvent is not particularly limited as long as it can dissolve the pressure-sensitive adhesive composition [I]. Examples thereof include ester solvents such as methyl acetate, ethyl acetate, methyl acetoacetate, and ethyl acetoacetate, acetone Further, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, aromatic solvents such as toluene and xylene, and alcohol solvents such as methanol, ethanol and propyl alcohol can be used. Among these, ethyl acetate and methyl ethyl ketone are preferably used from the viewpoints of solubility, drying property, price, and the like.

  In addition, the application of the pressure-sensitive adhesive composition [I] is performed by a conventional method such as roll coating, die coating, gravure coating, comma coating, or screen printing.

  The gel fraction of the pressure-sensitive adhesive layer produced by the above method is preferably 30 to 100%, particularly preferably 50 to 99%, more preferably 60 from the viewpoint of durability performance and light leakage prevention performance. ~ 95%. If the gel fraction is too low, durability tends to be insufficient due to insufficient cohesive force. Moreover, when the gel fraction is too high, tackiness is insufficient due to an increase in cohesive force, and the tackiness of the pressure-sensitive adhesive on the adherend tends to decrease.

  The pressure-sensitive adhesive layer produced by the above method preferably has a good tack feeling when touched with a finger, because it has good wettability when actually attached to an adherend, and therefore tends to improve workability. .

  In adjusting the gel fraction of the optical member pressure-sensitive adhesive to the above range, for example, adjusting the irradiation amount and irradiation intensity of the active energy ray, adjusting the type and amount of the unsaturated group-containing compound, This is achieved by adjusting the type of polymerization initiator and the combination ratio thereof, adjusting the blending amount of the polymerization initiator, adjusting the type and amount of the crosslinking agent, and the like. Moreover, since the gel fraction changes by each interaction, the irradiation amount and irradiation intensity | strength of said active energy ray, the composition ratio of a polymerization initiator, and addition amount need to balance each.

  The gel fraction is a measure of the degree of crosslinking (curing degree), and is calculated, for example, by the following method. That is, a pressure-sensitive adhesive sheet (not provided with a separator) in which a pressure-sensitive adhesive layer is formed on a polymer sheet (for example, polyethylene terephthalate film or the like) as a base material is wrapped with a 200-mesh SUS wire mesh, and 23 in toluene. The weight percentage of the insoluble pressure-sensitive adhesive component immersed in the wire mesh at 24 ° C. for 24 hours is defined as the gel fraction. However, the weight of the substrate is subtracted.

  Moreover, the thickness of the pressure-sensitive adhesive layer in the obtained optical member with the pressure-sensitive adhesive layer is not particularly limited, but is preferably 5 to 300 μm, particularly preferably 10 to 50 μm, and more preferably 12 to 30 μm. If the thickness of the pressure-sensitive adhesive layer is too thin, the adhesive physical properties tend to be difficult to stabilize, and if it is too thick, the thickness of the entire optical member tends to increase too much.

  The optical member with the pressure-sensitive adhesive layer of the present invention has a release sheet directly or after the release sheet is peeled off, and then the surface of the pressure-sensitive adhesive layer is bonded to a glass substrate and used for a liquid crystal display panel, for example. .

  The initial adhesive strength of the pressure-sensitive adhesive layer of the present invention is appropriately determined according to the material of the adherend. For example, when sticking on a glass substrate, it preferably has an adhesive strength of 0.2 N / 25 mm to 20 N / 25 mm, and more preferably 0.5 N / 25 mm to 10 N / 25 mm.

  The initial adhesive strength is calculated as follows. About a polarizing plate with an adhesive layer, it cuts into width 25mm width, peels off a release film, presses the adhesive layer side to a non-alkali glass board (Corning company make, "Corning XG"), A glass plate is bonded. Then, after performing an autoclave process (50 degreeC, 0.5 MPa, 20 minutes), 23 degreeC and 50% R. H. Then, after leaving for 24 hours, perform a 180 ° C. peel test.

The polarizing plate of the present invention, an optical film suitable for use in liquid crystal display equipment, e.g., a polarizing plate or a retardation plate on a polarizing plate, an elliptical polarizing plate, an optical compensation film, a brightness enhancing Phil beam are stacked And the like. Among them, a polarizing plate is particularly effective in the present invention.

  The polarizing plate used in the present invention is usually a laminate of a cellulose triacetate film as a protective film on both sides of a polarizing film. The polarizing film has an average degree of polymerization of 1,500 to 10,000, A uniaxially stretched film dyed with an aqueous solution of iodine-potassium iodide or a dichroic dye using a film made of a polyvinyl alcohol resin having a degree of conversion of 85 to 100 mol% as a raw film (usually 2 to 10 times, preferably Is a stretching ratio of about 3 to 7 times.

  The polyvinyl alcohol resin is usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, but a small amount of unsaturated carboxylic acid (including salt, ester, amide, nitrile, etc.), olefins, vinyl ether And a component copolymerizable with vinyl acetate, such as an unsaturated sulfonate. Moreover, what is called polyvinyl acetal resin and polyvinyl alcohol derivatives, such as polybutyral resin and polyvinyl formal resin, which are obtained by reacting polyvinyl alcohol with an aldehyde in the presence of an acid can be mentioned.

  In the present invention, in addition to a conventionally known polarizing plate, it is also very effective for a polarizing plate having a high viewing angle, which has been frequently used in recent years, and has higher light leakage resistance, durability, and reworkability. Can exhibit excellent effects.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” and “%” mean weight basis.

First, various acrylic resins were prepared as follows. In addition, regarding the measurement of the weight average molecular weight of acrylic resin, dispersion degree, and glass transition temperature, it measured according to the above-mentioned method.
In addition, regarding the measurement of a viscosity, it measured according to the 4.5.3 rotational viscometer method of JISK5400 (1990).

[Preparation of Acrylic Resin (A)] (See Table 1)
[Acrylic resin (A-1)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 94.8 parts of butyl acrylate (a1), 0.2 part of 2-hydroxyethyl acrylate (a2), acrylic First, 5 parts of acid (a2), 120 parts of ethyl acetate and 45 parts of acetone were charged. After heating to reflux, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and the mixture was refluxed at ethyl acetate for 3 hours. After the reaction, the solution was diluted with ethyl acetate, and the acrylic resin (A-1) solution (weight average molecular weight (Mw) 1,500,000, dispersity (Mw / Mn) 3.4, glass transition temperature -51 ° C., solid content 23 %, Viscosity 8000 mPa · s (25 ° C.)).

[Monofunctional monomer (B)]
The following aromatic ring-containing monomer (B1-1) was prepared as the aromatic ring-containing monomer (B1).
・ Ethoxylated O-phenylphenol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester A-LEN-10”)

As the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group, the following branched alkyl chain-containing (meth) acrylate monomer (B2-1) having 14 or more carbon atoms in the alkyl group Prepared.
Isostearyl acrylate (Osaka Organic Chemical Co., Ltd., trade name “I-STA”)

[Polyfunctional unsaturated compound (C)]
The following were prepared as the polyfunctional unsaturated compound (C-1).
Trimethylolpropane triacrylate (Kyoeisha, trade name “Light acrylate TMP-A”)

[Polymerization initiator (D)]
The following were prepared as the photopolymerization initiator (D-1).
A mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1: 1 (Ciba Specialty Chemicals, “Irgacure 500”)

[Crosslinking agent (E)]
The following were prepared as a crosslinking agent (E-1).
・ 55% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct (manufactured by Nippon Polyurethane Co., Ltd., “Coronate L-55E”)

[Silane coupling agent (F)]
The following were prepared as the silane compound (F-1).
・ Γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM403”)

[Examples 1 and 2 and Comparative Examples 1 to 3]
Prepare the pressure-sensitive adhesive composition to be a pressure-sensitive adhesive forming material for optical members by blending the components prepared and prepared as described above in the proportions shown in Table 2 below, and dilute them with ethyl acetate. (Viscosity [500 to 10000 mPa · s (25 ° C.)]) to prepare an adhesive composition solution.

Next, the pressure-sensitive adhesive composition solutions of Examples 1 and 2 and Comparative Examples 1 to 3 were applied to a polyester release sheet so that the thickness after drying was 25 μm, and dried at 90 ° C. for 3 minutes. The formed pressure-sensitive adhesive composition layer was transferred onto an EWV-integrated polarizing plate manufactured by Fuji Film Co., Ltd., and the peak illuminance was 600 mW / cm ² and the integrated exposure amount with an electrodeless lamp [H bulb of LH6UV lamp] manufactured by Fusion. : UV irradiation at 240 mJ / cm ² (120 mJ / cm ² × 2 passes), 23 ° C. × 65% R.D. H. The film was aged for 10 days under the above conditions to obtain a polarizing plate with an adhesive layer.
The polarizing plate was cut and used at 45 ° with respect to the stretching axis.

  Using the polarizing plate with the pressure-sensitive adhesive layer thus obtained, durability (wet heat resistance test, heat cycle test, heat resistance test), light leakage resistance, and reworkability were measured and evaluated according to the following methods. These results are also shown in Table 2 below.

〔durability〕
The release sheet of the obtained polarizing plate with the pressure-sensitive adhesive layer was peeled off, and the pressure-sensitive adhesive layer side was pressed against a non-alkali glass plate (Corning Corp., Eagle XG) to bond the polarizing plate and the glass plate. Thereafter, autoclaving (50 ° C., 0.5 MPa, 20 minutes) was performed, and then foaming and peeling were evaluated in the following durability test (wet heat resistance test). The polarizing plates were bonded so that the direction of the stretching axis was 45 °. In addition, the used test piece size was punched into 20 cm × 15 cm.

(1) Moisture and heat resistance test 60 ° C., 90% R.D. H. The following foaming was evaluated in a 150-hour durability test.

(Evaluation criteria)
(Foam)
○ ... No foaming or peeling is observed. Δ ... Foaming or peeling is 0.5mm or less from the end. X ... Foaming or peeling occurs from 0.5mm inside from the end. Often seen

(Light leakage resistance)
The release sheet of the obtained polarizing plate with the pressure-sensitive adhesive layer was peeled off, and the pressure-sensitive adhesive layer side was pressed against a non-alkali glass plate (Corning Corp., Eagle XG) to bond the polarizing plate and the glass plate. Thereafter, autoclaving (50 ° C., 0.5 MPa, 20 minutes) was performed, and light leakage resistance was also evaluated in an endurance test at 80 ° C. for 150 hours. The polarizing plates were bonded so that the stretching axes were 45 ° -135 ° on the front and back.
In addition, the used test piece size was punched into 20 cm × 15 cm.
(Evaluation criteria)
◎ ・ ・ ・ Light leakage occurs at the edge of 4 sides, but it is hardly noticeable ○ ・ ・ ・ Light leakage occurs at the edge of 4 sides △ ・ ・ ・ Light leakage occurs at the edge of 4 sides × ... Light leaks strongly at the edges of the four sides

[Reworkability]
The obtained polarizing plate with the pressure-sensitive adhesive layer was cut to a width of 25 mm, and then bonded to non-alkali glass (Eagle XG manufactured by Corning) and autoclaved (50 ° C., 0.5 MPa, 20 minutes). After leaving still in a 50% RH atmosphere for 24 hours, a 180 degree peel test was performed and evaluated as follows.
(Evaluation criteria)
○… No glue residue is seen on the glass ×… Glue residue is seen on the glass.

注）・（Ａ）〜（Ｆ）における表中の（ ）内の数値は配合重量部である。

Note) · The numerical value in () in the table in (A) to (F) is the weight part.

  From the pressure-sensitive adhesive composition containing both the aromatic ring-containing monomer (B1) and the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more alkyl groups as the monofunctional monomer (B). The adhesives for optical members in Examples 1 and 2 are excellent in durability, light leakage resistance, and reworkability, while having a branched alkyl chain-containing (meth) acrylate monomer having an alkyl group having 14 or more carbon atoms. The pressure-sensitive adhesive for optical members of Comparative Examples 1 to 3 consisting of a pressure-sensitive adhesive composition containing only the aromatic ring-containing monomer (B1) without using (B2) may be inferior in durability and light leakage resistance. Recognize.

  In the WV-integrated polarizing plate, light leakage can be suppressed by positively increasing the birefringence of the adhesive, but when the birefringence of the adhesive is made positive only with an aromatic compound, the wavelength dispersion of the adhesive It is considered that the wavelength in the visible region cannot be suppressed in a well-balanced manner, and in addition to the aromatic compound as in Examples 1 and 2, a monomer having a relatively long branched alkyl chain is used. When used in combination, the positive birefringence can be increased while reducing the wavelength dispersibility of the pressure-sensitive adhesive. Therefore, it is considered that a more excellent light leakage suppression effect is exhibited.

The pressure-sensitive adhesive for polarizing plates of the present invention has a pressure-sensitive adhesive layer after curing with active energy rays and / or heat, which is excellent in adhesiveness between the polarizing plate and the glass substrate even in a high temperature and high humidity environment. A liquid crystal display device in which foaming and peeling do not occur between the agent layer and the glass substrate, and color unevenness and light leakage do not occur can be obtained. Therefore, it is very useful as an adhesive to obtain a pressure-sensitive adhesive layer-carrying polarizing plate and an image display device obtained by using the polarizing plate pressure-sensitive adhesive.

Claims (8)

Acrylic resin (A),
An ethylenically unsaturated compound (B) containing one ethylenically unsaturated group,
And an ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups
The pressure-sensitive adhesive composition [I] containing is a pressure-sensitive adhesive that is cured by active energy rays and / or heat,
An ethylenically unsaturated compound (B) containing one ethylenically unsaturated group is
An aromatic ring-containing monomer (B1) and a branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group ,
The content of the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group is 10 to 80 parts by weight with respect to 100 parts by weight of the acrylic resin (A),
The content of the aromatic ring-containing monomer (B1) is 5 to 50 parts by weight,
The content of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is 5 to 50 parts by weight,
The content ratio (weight ratio) between the aromatic ring-containing monomer (B1) and the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is (B1) / (B2) = 0.5. It is -3, The adhesive for polarizing plates characterized by the above-mentioned. Of the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group to the total amount of the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group and the ethylenically unsaturated compound (C) The pressure-sensitive adhesive for polarizing plates according to claim 1, wherein the content (mol%) is larger than 50 mol%. The pressure-sensitive adhesive composition [I] contains a polymerization initiator (D), and the pressure-sensitive adhesive for polarizing plates according to claim 1 or 2 . The pressure-sensitive adhesive composition [I] contains a crosslinking agent (E), and is crosslinked by a crosslinking agent. The pressure-sensitive adhesive for polarizing plates according to any one of claims 1 to 3 . The pressure-sensitive adhesive for polarizing plates according to any one of claims 1 to 4, wherein the gel fraction is 30 to 100%. Pressure-sensitive adhesive layer-carrying polarizing plate comprising a laminated structure of the adhesive layer and the polarizing plate comprising a polarizing plate pressure-sensitive adhesive according to any one claims 1 to 5. An image display device comprising the polarizing plate with an adhesive layer according to claim 6 . An acrylic resin (A), an ethylenically unsaturated compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups, As an ethylenically unsaturated compound (B) containing one ethylenically unsaturated group, an aromatic ring-containing monomer (B1) and a branched alkyl chain-containing (meth) acrylate monomer (B2) having an alkyl group with 14 or more carbon atoms The content of the ethylenically unsaturated compound (B) containing one ethylenically unsaturated group is 10 to 80 parts by weight with respect to 100 parts by weight of the acrylic resin (A). The content of the containing monomer (B1) is 5 to 50 parts by weight, and the content of the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is 5 to 50 parts by weight. The content ratio (weight ratio) of the aromatic ring-containing monomer (B1) and the branched alkyl chain-containing (meth) acrylate monomer (B2) having 14 or more carbon atoms in the alkyl group is (B1) / (B2) = 0. the active energy ray and / or thermosetting polarizer pressure-sensitive adhesive composition characterized .5～3 der Rukoto.