JP5854791B2 - Adhesive, adhesive for optical member, optical member with adhesive layer, image display device, active energy ray-curable adhesive composition - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive (pressure-sensitive adhesive), a pressure-sensitive adhesive for optical members, an optical member with a pressure-sensitive adhesive layer obtained using the same, an image display device, and an active energy ray-curable pressure-sensitive adhesive composition. Specifically, an optical film (polarizing film, retardation film, optical compensation film, brightness enhancement film, etc.) suitably used for liquid crystal display devices, organic EL display devices, image display devices such as PDP, etc. A pressure-sensitive adhesive for an optical member used for bonding an optical laminate in which a polarizing film is coated with a protective film such as a cellulose triacetate film and a glass substrate of a liquid crystal cell, and a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive for the optical member The present invention relates to an optical member with an adhesive layer, particularly a polarizing plate with an adhesive layer.

  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 describes an adhesive having excellent optical properties by using an acrylic resin copolymerized with an aromatic monomer, and Patent Document 2 describes an aromatic resin containing an aromatic ring-containing low molecular weight. A pressure-sensitive adhesive having excellent optical properties by blending a compound is described, and Patent Document 3 discloses that an ethylenically unsaturated monomer (UV curable monomer) used in combination with an acrylic resin is subjected to crosslinking polymerization by irradiation with active energy rays. In addition, an adhesive having a good balance between durability and optical properties is described.

JP 2005-53976 A WO2007 / 072799 JP 2009-132909 A

  However, although the technique disclosed in Patent Document 1 shows a certain optical characteristic, a large amount of aromatic monomer is copolymerized in order to clear the recent demand for higher optical characteristics using this technique. It is necessary to let

However, when polymerization is carried out using a large amount of aromatic monomer, the viscosity in the reaction solution increases, so that a high molecular weight generally used in an adhesive for optical applications (for example, a weight average molecular weight of 1 million or more). It is difficult to produce an acrylic resin, and in general, it is difficult to remove the diacrylate body of impurities generated during the production of aromatic monomers by distillation or the like. In many cases, it was difficult to produce a high molecular weight acrylic resin under the influence of such impurities.
In addition, when low molecular weight aromatic monomers such as benzyl acrylate and phenoxyethyl acrylate, which are relatively easy to polymerize, are used for polymerization, residual monomers may remain after the formation of the adhesive layer. The odor was also a problem.

  Even with the technique disclosed in the above-mentioned Patent Document 2, although it has been obtained that the color unevenness and light leakage are hardly generated, the low molecular weight compound having two or more benzene rings used in Patent Document 2, Due to high crystallinity and low hydrophobic groups, compatibility with acrylic resins is poor.Furthermore, it is a low molecular weight component and its cohesive strength is low, so the cohesive strength as an adhesive does not increase and the durability of the liquid crystal display device is increased. There was a problem of getting worse.

  In the technique disclosed in Patent Document 3 described above, although it is surely excellent in durability and optical properties in a well-balanced manner, an ethylenically unsaturated monomer having two or more ethylenically unsaturated groups is mainly used as a UV curable monomer. The cross-link density and elastic modulus of the pressure-sensitive adhesive layer after UV irradiation are very high compared to general pressure-sensitive adhesives, and the tackiness of the pressure-sensitive adhesive is lowered and the tackiness when the pressure-sensitive adhesive is bonded to the adherend. There was a problem of being bad.

  Further, in recent years, in the use of an adhesive, when it is bonded to a substrate, it may be necessary to re-bond due to a bonding error or the like, so that it is also required to have excellent re-stickability (reworkability). ing.

  Therefore, in the present invention, in such a background, when an optical member such as a polarizing plate and a glass substrate are bonded together, the adhesive has excellent rework performance (reattachability), durability, and optical characteristics (light leakage resistance). An object of the present invention is to provide an adhesive, particularly an adhesive for optical members.

  However, as a result of intensive studies in view of such circumstances, the present inventors have found one ethylenically unsaturated group as a curable ethylenically unsaturated monomer in the active energy ray and / or thermosetting pressure-sensitive adhesive. Rework performance (adhesion) by using two kinds of acrylic resin containing a hydroxyl group in the side chain and an acrylic resin containing a carboxyl group in the side chain as an acrylic resin. The present inventors have found that an adhesive having a good balance in terms of repairability, durability, and optical properties (light leakage resistance) can be obtained, and the present invention has been completed.

That is, the gist of the present invention, the acrylic resin containing a hydroxyl group in the side chain (A1), an aromatic containing one acrylic resin (A2), d ethylenic unsaturated group containing a carboxyl group in a side chain The pressure-sensitive adhesive composition [I] containing the compound (B) , the ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups, and the crosslinking agent (E) is crosslinked by the crosslinking agent, and , An adhesive that is cured by active energy rays and / or heat, and the acrylic resin (A1) containing a hydroxyl group in the side chain contains the hydroxyl group-containing monomer (a1) and substantially contains the carboxyl group-containing monomer. An acrylic resin obtained by copolymerizing a copolymer component not contained in the resin, wherein the acrylic resin (A2) containing a carboxyl group in the side chain contains a carboxyl group-containing monomer (a′1), and An acrylic resin obtained by copolymerizing a copolymer component that does not contain an acid group-containing monomer, and an aromatic compound (B) containing one ethylenically unsaturated group is an acrylic resin (A) or a crosslinking agent (E It is an aromatic compound that does not contain a functional group that easily reacts with the adhesive, and the crosslinking agent (E) contains an isocyanate crosslinking agent .
Furthermore, an optical member pressure-sensitive adhesive using the above-mentioned pressure-sensitive adhesive, a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive for the optical member and an optical member with a pressure-sensitive adhesive layer including a laminated structure of the optical member, and an image display comprising the optical member It relates to the device.

The pressure-sensitive adhesive of the present invention is excellent in light leakage resistance, but the reason why light leakage does not occur is estimated as follows.
In general, the cause of light leakage is that stress is concentrated on the triacetyl cellulose (TAC) protective film of the polarizing plate due to shrinkage when the polarizing plate is exposed to heat-resistant conditions, and birefringence (positive photoelastic coefficient). Or the acrylic polymer of the pressure-sensitive adhesive is oriented by following the contraction of the polarizing plate, and birefringence (generally having a negative photoelastic coefficient) is presumed to occur. The

When comparing the conventional birefringence derived from an acrylic polymer having a negative photoelastic coefficient and the birefringence derived from a TAC-based protective film having a positive photoelastic coefficient, it is estimated that the birefringence derived from the acrylic polymer is larger. That is, when the polarizing plate contracts and tensile stress is generated (the direction in which the stress is generated is defined as the x-axis direction), the refractive index of the acrylic polymer increased in the y-axis direction is set in the y-axis direction of the TAC protective film. The effect of reducing the refractive index cannot be offset. In order to eliminate (cancel) this birefringence, it is necessary to reinforce the positive photoelastic coefficient somewhere.
Therefore, in the present invention, an appropriate amount of a component having a positive photoelastic coefficient is blended with the acrylic resins (A1) and (A2), and combined with the positive photoelastic coefficient of the TAC protective film, the conventional acrylic polymer is combined. We focused on canceling the negative photoelasticity that occurs. Specifically, by using a certain amount of the polymer of the aromatic compound (B) as a component having a positive photoelastic coefficient, a polarizing plate with an adhesive layer having excellent light leakage resistance could be obtained. Is.

  The pressure-sensitive adhesive of the present invention can be suitably used particularly for optical member applications, and the pressure-sensitive adhesive layer after curing with active energy rays and / or heat is excellent in rework performance (re-stickability) and high temperature. Even under high-humidity environment, the optical laminate is excellent in adhesion between an optical member such as a polarizing plate and a glass substrate, and there is no foaming or peeling between the pressure-sensitive adhesive layer and the glass substrate. A liquid crystal display device in which light leakage does not occur can be obtained.

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.

First, the pressure-sensitive adhesive composition [I] of the present invention will be described.
The pressure-sensitive adhesive composition [I] of the present invention comprises two acrylic resins (A), an acrylic resin (A1) containing a hydroxyl group in the side chain and an acrylic resin (A2) containing a carboxyl group in the side chain. An aromatic compound (B) containing a seed and further containing one ethylenically unsaturated group, an ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups, and a crosslinking agent (E) It contains.

Acrylic resins containing a hydroxyl group in the side chain of the present invention (A1) (hereinafter sometimes abbreviated as "acrylic resin (A1)".) Has a water acid group-containing monomer in the copolymerization together to how Therefore, Ru is produced.

The copolymerization component containing a hydroxyl-containing monomer (a1), other copolymerizable components and be used for ash is copolymerized, acrylic resin conveniently containing a hydroxyl group in the side chain in the case of industrial production It is preferable in that (A1) is obtained.
Hereinafter, the case where it manufactures by the method of copolymerizing a hydroxyl-containing monomer (a1) as acrylic resin (A1) is demonstrated.

  Examples of the hydroxyl group-containing monomer (a1) include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8- Hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate and other (meth) acrylic acid hydroxyalkyl esters, diethylene glycol (meth) acrylate, polyethylene glycol mono (meth) Polyethylene glycol derivatives such as acrylate, polypropylene glycol derivatives such as polypropylene glycol mono (meth) acrylate, polyethylene glycol-polypropylene glycol -Oxyalkylene-modified monomers such as mono (meth) acrylate, poly (ethylene glycol-tetramethylene glycol) mono (meth) acrylate, poly (propylene glycol-tetramethylene glycol) mono (meth) acrylate, N-hydroxyethyl (meth) Primary hydroxyl group-containing monomers such as acrylamide; Secondary hydroxyl group-containing monomers such as 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate; 2,2 -Tertiary hydroxyl group-containing monomers such as dimethyl-2-hydroxyethyl (meth) acrylate.

  Among the hydroxyl group-containing monomers (a1), a primary hydroxyl group-containing monomer is preferable in terms of excellent reactivity with a crosslinking agent, and it is more preferable to use 2-hydroxyethyl (meth) acrylate. It is particularly preferable in that it is easy to produce with few impurities such as.

  As the hydroxyl group-containing monomer (a1) used in the present invention, it is also preferable to use a monomer having a content of di (meth) acrylate as an impurity of 0.5% or less, more preferably 0.2% or less. It is preferable to use less than 0.1%, specifically 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate.

  In the acrylic resin (A1) used in the present invention, the content of the hydroxyl group-containing monomer (a1) in the case of copolymerizing the hydroxyl group-containing monomer (a1) is 0.1 to 20% by weight based on the entire copolymerization component. The content is preferably 0.2 to 10% by weight, more preferably 0.5 to 5% by weight. When the content of the hydroxyl group-containing monomer (a1) is too large, the heat and humidity resistance tends to be lowered. When the content is too small, the crosslinking reaction cannot be efficiently performed, and foaming or the like tends to occur due to durability.

  As other copolymerization components other than the hydroxyl group-containing monomer (a1), (meth) acrylic acid alkyl ester monomer (a2), if necessary, a functional group-containing monomer (a3) other than the hydroxyl group-containing monomer (a1) and others The copolymerizable monomer (a4)

  As the (meth) acrylic acid alkyl ester monomer (a2), 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 can be used alone or in combination of two or more.

  Among these (meth) acrylic acid alkyl ester monomers (a2), 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 of the (meth) acrylic acid alkyl ester monomer (a2) when copolymerized is preferably 40 to 99.9% by weight, particularly preferably 80 to 99.8%, based on the entire copolymerization component. % By weight, more preferably 95-99.5% by weight. If the content of the (meth) acrylic acid alkyl ester monomer (a2) is too small, the adhesive properties tend to be lowered. Due to the decrease in the group-containing monomer, the crosslinking density tends to decrease and the durability tends to decrease.

  Examples of the functional group-containing monomer (a3) include monomers containing a functional group that can become a cross-linking point by reacting with a cross-linking agent (E) described later. Examples include a carboxyl group-containing monomer, an amino group-containing monomer, and acetoacetyl. Examples thereof include a group-containing monomer, an isocyanate group-containing monomer, and a glycidyl group-containing monomer. Among these, a carboxyl group-containing monomer is preferably used in that a crosslinking reaction can be efficiently performed.

  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 (a3) may be used alone or in combination of two or more.

  The content in the case of copolymerizing the functional group-containing monomer (a3) is preferably 0 to 20% by weight, particularly preferably 0.01 to 5% by weight, more preferably 0, based on the entire copolymerization component. 0.1 to 1% by weight, and if the content of the functional group-containing monomer (a3) is too large, the adhesive strength tends to increase too much.

As other copolymerizable monomer (a4), for example,
Phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, styrene, α-methylstyrene, biphenyloxyethyl ( Aromatic ring-containing monomers such as (meth) acrylate;
2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (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, octoxypolyethylene glycol-polypropylene glycol-mono (meth) acrylate, Lauro Xylethylene glycol mono (meth) acrylate, stearoxypolyethylene glycol mono (meth) acrylate Monomers containing an alkoxy group and an oxyalkylene group of bets like;
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.

  The content in the case of copolymerizing the other copolymerizable monomer (a4) is preferably 0 to 40% by weight, particularly preferably 3 to 30% by weight, more preferably 8%, based on the entire copolymerization component. When the content of the other copolymerizable monomer (a4) is too large, the adhesive performance tends to be lowered.

In the present invention, the acrylic resin (A1) is required to contain substantially no carboxyl group-containing monomer as a copolymerization component other than the hydroxyl group-containing monomer (a1). Means that the content of the carboxyl group-containing monomer is 1% by weight or less, preferably not contained.

  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.

  In the present invention, the acrylic resin (A1) is produced by polymerizing the monomer components (a1) to (a4). In the polymerization, solution radical polymerization, suspension polymerization, bulk polymerization, It can be performed by a conventionally known method such as emulsion polymerization. For example, polymerization of the hydroxyl group-containing monomer (a1), (meth) acrylic acid alkyl ester monomer (a2), other functional group-containing monomer (a3), other copolymerizable monomer (a4), etc. in an organic solvent. A monomer and a polymerization initiator (azobisisobutyronitrile, azobisisovaleronitrile, benzoyl peroxide, etc.) are mixed or dropped and polymerized at reflux or at 50 to 90 ° C. for 2 to 20 hours.

  The weight average molecular weight of the acrylic resin (A1) is usually 100,000 to 3,000,000, preferably 300,000 to 2,500,000, particularly preferably 600,000 to 2,000,000, particularly preferably 800,000 to 1,500,000. . If the weight average molecular weight is too small, the durability tends to decrease. If 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 properties and cost.

  The degree of dispersion (weight average molecular weight / number average molecular weight) of the acrylic resin (A1) is preferably 20 or less, particularly preferably 15 or less, more preferably 10 or less, and particularly preferably 7 or less. preferable. If the degree of dispersion is too high, the durability 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 2 from the viewpoint of production limit.

  Furthermore, the glass transition temperature of the acrylic resin (A1) is preferably −80 to −20 ° C., particularly preferably −75 to −25 ° C., more preferably −60 to −30 ° C. If the glass transition temperature is too high, tackiness may occur. When it is too low, heat resistance tends to decrease.

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)

Acrylic resins containing a carboxyl group in the side chain of the present invention (A2) (hereinafter, may be abbreviated as "acrylic resin (A2)".) Is, mosquitoes carboxyl way to a group containing monomer copolymerization together to thus Ru are manufactured.

The copolymerization component containing a carboxyl group-containing monomer (a'1), be used for ash is another copolymerizable component copolymerized, easily containing a carboxyl group in the side chain Upon industrially produced It is preferable at the point which can obtain acrylic resin (A2).
Hereinafter, the case where the acrylic resin (A2) is produced by a method of copolymerizing the carboxyl group-containing monomer (a′1) will be described.

  Examples of the carboxyl group-containing monomer (a′1) include acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N-glycolic acid, cinnamic acid, and (meth) acrylic. Michael adduct of acid (for example, acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid trimer, acrylic acid tetramer, methacrylic acid tetramer, etc.), 2- (meth) acryloyloxyethyl dicarboxylic acid monoester (for example, 2 -Acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxyethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hex Sahydrophthalic acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid monoester, etc.), 2-carboxyethyl acrylate and the like.

  Among the carboxyl group-containing monomers (a′1), (meth) acrylic acid and its Michael adduct are preferable, and acrylic acid is particularly preferable in terms of availability and stable production.

  In the acrylic resin (A2) used in the present invention, the content in the case of copolymerizing the carboxyl group-containing monomer (a′1) may be 0.5 to 30% by weight based on the entire copolymerization component. It is preferably 1 to 20% by weight, more preferably 2 to 12% by weight. If the content of the carboxyl group-containing monomer (a′1) is too large, the adhesive strength tends to increase too much, or the cohesive strength tends to be insufficient and the durability tends to decrease. If the content is too small, the adhesive strength decreases too much. The fraction tends to increase too much and the durability and light leakage resistance tend to decrease.

  As other copolymerization components other than the carboxyl group-containing monomer (a′1), a (meth) acrylic acid ester monomer (a′2), if necessary, a functional group other than the carboxyl group-containing monomer (a′1) Examples thereof include the monomer (a′3) and other copolymerizable monomers (a′4).

  As the (meth) acrylic acid alkyl ester monomer (a′2), the same as the above-mentioned (meth) acrylic acid ester monomer (a2) can be used.

  The content when the (meth) acrylic acid alkyl ester monomer (a′2) is copolymerized is preferably from 30 to 99.5% by weight, particularly preferably from 70 to 99, based on the entire copolymerization component. % By weight, more preferably 88 to 98% by weight. If the content of the (meth) acrylic acid alkyl ester monomer (a′2) is too small, the adhesive performance tends to be lowered. There is a tendency that the ratio of the group-containing monomer is reduced and the adhesion is likely to be lowered.

Such functional group-containing monomer (a'3), include monomers containing a functional group capable of being a crosslinking site by reacting with later crosslinking agent (E), for example, amino group-containing monomer, acetoacetyl group containing monomers, isocyanate group-containing monomers, glycidyl group-containing monomers are exemplified et be.

  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 (a′3) may be used alone or in combination of two or more.

  The content in the case of copolymerizing the functional group-containing monomer (a′3) is preferably 0 to 20% by weight, particularly preferably 0.01 to 5% by weight, more preferably, based on the entire copolymerization component. Is 0.1 to 1% by weight, and if the content of the functional group-containing monomer (a′3) is too large, the adhesive strength tends to increase too much.

  As the other copolymerizable monomer (a′4), the same copolymerizable monomer (a4) as described above can be used.

  The content in the case of copolymerizing the other copolymerizable monomer (a′4) is preferably 0 to 40% by weight, particularly preferably 3 to 30% by weight, more preferably based on the entire copolymerization component. Is 8 to 20% by weight, and if the content of the other copolymerizable monomer (a′4) is too large, the tackiness tends to decrease.

Further, acrylic resin (A2), hydroxyl group-containing monomers have Na have contains as a copolymerization component other than the carboxyl group-containing monomer (a'1).

  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.

  In the present invention, the acrylic resin (A2) is produced by polymerizing the monomer components (a′1) to (a′4), and the polymerization is performed by a conventionally known method. For example, it can be manufactured by the same method as the acrylic resin (A1) described above.

  About the weight average molecular weight of acrylic resin (A2), it is 100,000-3 million normally, Preferably it is 300,000-2 million, Most preferably, it is 600,000-2 million. If the weight average molecular weight is too small, sufficient cohesive force tends not to be obtained. If the weight average molecular weight is too large, a large amount of diluent solvent is required, which tends to be undesirable in terms of coating properties and cost.

  The degree of dispersion (weight average molecular weight / number average molecular weight) of the acrylic resin (A2) is preferably 20 or less, particularly preferably 15 or less, more preferably 10 or less, and particularly preferably 7 or less. preferable. When the degree of dispersion is too high, the durability of the pressure-sensitive adhesive layer, such as heat and moisture resistance and light leakage, tends to decrease. The lower limit of the degree of dispersion is usually 2 from the viewpoint of production limit.

  Further, the glass transition temperature of the acrylic resin (A2) is preferably −80 to −20 ° C., particularly preferably −75 to −25 ° C., more preferably −60 to −30 ° C. If the glass transition temperature is too high, tackiness may occur. When it is too low, heat resistance tends to decrease.

  In addition, said weight average molecular weight, number average molecular weight, and glass transition temperature can be calculated | required similarly to the above.

In the present invention, the blending ratio (weight ratio) of the acrylic resin (A1) and the acrylic resin (A2) is preferably (A1) :( A2) = 50: 50 to 99: 1, particularly preferably. (A1) :( A2) = 60: 40 to 95: 5, more preferably (A1) :( A2) = 70: 30 to 90:10.
If the content ratio of the acrylic resin (A1) relative to the acrylic resin (A2) is too large, the gel fraction greatly increases depending on the addition amount of the crosslinking agent, and the durability and light leakage resistance are reduced. There exists a tendency and there exists a tendency for adhesive force to rise too much when too small.

  In the present invention, the fact that the difference in weight average molecular weight between the acrylic resin (A1) and the acrylic resin (A2) is small can increase the cohesive strength of the polymer network after cross-linking and improve the durability. Therefore, specifically, the ratio ((A1) / (A2)) of the weight average molecular weight of the acrylic resin (A1) and the acrylic resin (A2) is (A1) / (A2) = 0.5 to It is preferably 1.5, more preferably (A1) / (A2) = 0.8 to 1.2, and still more preferably (A1) / (A2) = 0.9 to 1.1.

Here, in the present invention, the content ratio (molar ratio) between the hydroxyl group and the carboxyl group contained in the pressure-sensitive adhesive composition [I] is preferably hydroxyl group / carboxyl group = 0.15 to 20, particularly Preferably, hydroxyl group / carboxyl group = 0.5 to 10, more preferably hydroxyl group / carboxyl group = 1.5 to 2.5. If the content ratio of the hydroxyl group to the carboxyl group is too large, depending on the amount of the crosslinking agent added, there is a tendency that the gel fraction greatly increases and the durability and light leakage resistance tend to decrease. Tend to rise too much.
The hydroxyl group and carboxyl group in the pressure-sensitive adhesive composition [I] are preferably functional groups substantially derived from the acrylic resin (A1) and the acrylic resin (A2). It may contain a derived functional group.

  Moreover, in this invention, you may contain other acrylic resins other than acrylic resin (A1) and acrylic resin (A2) in the range which does not impair the effect of this invention.

  The aromatic compound (B) containing one ethylenically unsaturated group used in the present invention (hereinafter sometimes abbreviated as “monofunctional aromatic compound (B)”) includes an aromatic ring in the molecule. And a compound having one ethylenically unsaturated group. Examples of the functional group containing such an ethylenically unsaturated group include a (meth) acryloyl group, a crotonoyl group, a vinyl group, and an allyl group.

  The monofunctional aromatic compound (B) is a compound containing a (meth) acryloyl group among the above functional groups in its structure, that is, a mono (meth) acrylate compound, an active energy ray and / or Or it is preferable at the point which reaction tends to advance when it hardens | cures with a heat | fever.

  The number of aromatic rings contained in the monofunctional aromatic compound (B) may be one, or a plurality may be contained. A compound containing one aromatic ring is preferable in terms of balancing the physical properties of the adhesive, and it is a compound containing two aromatic rings in terms of efficiently controlling the refractive index and birefringence of the adhesive layer. Is preferred, but in particular, it is preferred to contain one aromatic ring.

Specific examples of the monofunctional aromatic compound (B) include ether-based monofunctional aromatic compounds (b1), ester-based monofunctional aromatic compounds (b2), and the like. the monofunctional aromatic compounds (b1), for example, phenol-induced body. Examples of the monofunctional aromatic compounds of the ester type (b2), for example, benzoic acid derivatives, 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.
The structural moiety containing such (meth) acryloyl group, have preferably those represented by the following general formula also contain oxyalkylene structure (1).

（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.
Further, the alkylene group may have a substituent, the substituent is usually a halogen atom, an alkoxy group, an amino group, a sulfanyl group, an aryl group, Ru is like a heteroaryl group.

  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-moisture resistance of the pressure-sensitive adhesive layer 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, phenyldiethylene glycol (meth) acrylate, phenyl polyethylene glycol (meth) acrylate, phenoxypropyl (meth) acrylate, and phenyldipropylene glycol (meth). acrylate, phenyl polypropylene glycol (meth) acrylate, et butoxy phenyl phenyl (meth) acrylate and the like, and commercially available products, phenyl polyethylene glycol acrylate (Osaka organic chemical Co., Ltd., trade name "Viscoat # 193"), off Yenyldiethylene glycol acrylate (Kyoeisha, trade name “Light acrylate P2HA”), ethoxylated o-phenylphenyl acrylate (Shin Nakamura Chemical Co., trade name “NK S Ter A-LEN-10 ") and the like.

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 2 -methacryloyloxyethylphthalic acid (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “CB-1”) as a commercially available product.

In addition, as a monofunctional compound (B), at least 1 sort (s) chosen from the functional group (specifically an isocyanate group, a hydroxyl group, and a carboxyl group) which is easy to react with acrylic resin (A) and the below-mentioned crosslinking agent (E). ) that do not contain a.
When it contains a reactive functional group, it is incorporated into the crosslinked network of the acrylic resin (A), and the degree of freedom of the cured product of the monofunctional compound (B) and the polyfunctional unsaturated compound (C) described later Is lost, and the light leakage resistance improving effect cannot be obtained sufficiently.

  The molecular weight of the monofunctional aromatic compound (B) is usually 200 to 10,000, preferably 210 to 1,000, particularly preferably 220 to 500. If the molecular weight is too large, the aromatic ring concentration tends to decrease, making it difficult to adjust the refractive index and adjusting birefringence. If the molecular weight is too small, the pressure-sensitive adhesive tends to volatilize and the effect of the invention is difficult to obtain. Tend to be.

  The monofunctional aromatic compound (B) preferably has a flash point of 145 ° C. or higher, particularly preferably 145 to 500 ° C., more preferably 150 to 400 ° C., particularly preferably 160 to 300 ° C. is there. If the flash point is too high, the birefringence adjusting ability tends to decrease due to an increase in molecular weight. If the flash point is too small, volatility increases, and the adhesive is likely to volatilize when dried, making it difficult to obtain the effects of the invention. Tend.

  Examples of the monofunctional aromatic compound (B) satisfying such a flash point include phenyl diethylene glycol acrylate (flash point: 165 ° C.), ethoxylated orthophenylphenol acrylate (flash point: 170-199 ° C.), and the like. [<Reference value>, phenoxyethyl acrylate (flash point: 139 to 141 ° C.), benzyl acrylate (flash point: 107 ° C.)]

  In addition, as the monofunctional aromatic compound (B), in a volatility test in which 1 g of the monofunctional aromatic compound (B) and 10 g of ethyl acetate are mixed and then dried under the condition of 105 ° C. × 5 min, What the ratio of the remainder (weight) of a functional aromatic compound (B) is 90% or more is preferable.

  Examples of the monofunctional aromatic compound (B) that satisfies the residual ratio in the volatility test include phenyldiethylene glycol acrylate (residual ratio: 100%), ethoxylated orthophenylphenol acrylate (residual ratio: 100%). ). [<Reference value>, phenoxyethyl acrylate (residual ratio: 89.5%), benzyl acrylate (residual ratio: 67.8%), styrene (residual ratio: 0.5%)]

  The content of the monofunctional aromatic compound (B) is preferably 3 to 300 parts by weight, more preferably 100 parts by weight in total of the acrylic resin (A1) and the acrylic resin (A2). Is 5 to 100 parts by weight, particularly preferably 8 to 60 parts by weight, particularly preferably 25 to 45 parts by weight. When the content of the monofunctional aromatic compound (B) is too large, both durability and light leakage resistance tend to decrease. When the content is too small, the refractive index becomes too low, and light leakage resistance tends to decrease. There is.

In the present invention, the acrylic resin (A), the monofunctional aromatic compound (B ), the ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups, and the crosslinking agent (E) are added. The pressure-sensitive adhesive composition [I] contained as an essential component is cured by active energy rays and / or heat (irradiation with active energy rays and / or heating) to obtain a pressure-sensitive adhesive.

When performing curing by the active energy ray and / or heat, the pressure-sensitive adhesive composition [I] is an ethylenically unsaturated compound containing a d ethylenic unsaturated group two or more (C) (hereinafter, "multifunctional It may be abbreviated as “Saturated unsaturated compound (C)”) in that the cohesive force of the entire pressure-sensitive adhesive layer can be adjusted , and it is necessary to contain the polymerization initiator (D). It is preferable at the point which can stabilize reaction at the time of a beam irradiation and / or a 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.

In the present invention, as a method of curing the pressure-sensitive adhesive composition [I], the component (A) and (B) Ingredient, in addition to the component (C) (optionally component (D)) , further cross-linking agent (E) and that is contained, the pressure-sensitive adhesive composition [I], Ru to perform the curing by cross-linking agents and curing by active energy ray and / or heat (crosslinking).

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. although, further by a combination child curing (crosslinking) by crosslinking agents, to increase the crosslink density of the adhesive, so that more that more excellent with respect to durability can be obtained by increasing the cohesion.

Further, when the acrylic resin (A) is an unsaturated group-containing acrylic resin, the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C) by active energy rays and / or heat are used. is not limited to the polymerization, unsaturated group-containing acrylic resin (a) and monofunctional aromatic compound (B) to contact and also occurs curing due to polymerization, such as the polyfunctional unsaturated compound (C) and Become.

  As the polyfunctional unsaturated compound (C), for example, an ethylenically unsaturated monomer containing two or more ethylenically unsaturated groups in one molecule, for example, a bifunctional monomer, a trifunctional or higher monomer, Urethane (meth) acrylate compounds, epoxy (meth) acrylate compounds, and 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 300-4000 normally as the weight average molecular weight.

  The content of the polyfunctional unsaturated compound (C) is preferably 0.01 to 100 parts by weight with respect to a total of 100 parts by weight of the acrylic resin (A1) and the acrylic resin (A2). Especially preferably, it is 0.5-20 weight part, More preferably, it is 1-10 weight part. When the content of the polyfunctional unsaturated compound (C) is too large, both durability and light leakage resistance tend to decrease, and when it is too small, the light leakage resistance tends to be insufficient.

  In the present invention, the monofunctional aromatic compound (B) and the above-described monofunctional aromatic compound (B) can be appropriately adjusted to have a proper crosslinking density, to properly adjust the tack feeling, and to balance durability. The content ratio of the monofunctional aromatic compound (B) with respect to the total amount of the polyfunctional unsaturated compound (C) is preferably greater than 50 mol%, particularly preferably greater than 50 mol% and less than 100 mol%, more preferably 55. ˜99 mol%, particularly preferably 60 to 98 mol%.

  When the content ratio of the monofunctional aromatic compound (B) with respect to the total amount of the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C) is too small, the amount relative to the monofunctional aromatic compound (B) Since the content of the polyfunctional unsaturated compound (C) increases, the crosslink density tends to increase too much and the tackiness tends to be insufficient. In addition, when the content ratio of the monofunctional aromatic compound (B) with respect to the total amount of the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C) is too large, the monofunctional aromatic compound (B ), The content of the polyfunctional unsaturated compound (C) decreases, so that the crosslinking density does not increase so much and the durability tends to be poor.

  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.

  Moreover, when using the said photoinitiator (d1), adhesive composition [I] is hardened by active energy ray irradiation, and when using a thermal polymerization initiator (d2), adhesive composition [ I] is cured, but it is also preferable to use both together if 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, 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) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy -3 Thioxanthones such as 4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl- And acyl phosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; In addition, as for these photoinitiators (d1), only 1 type may be used independently and 2 or more types may be used 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, only 1 type may be used independently for these thermal polymerization initiators, and 2 or more types may be used together.

  About content of the said polymerization initiator (D), 0.01-10 weight part with respect to a total of 100 weight part of the said acrylic resin (A1) and acrylic resin (A2), Especially 0.1-0.1 weight part. It is preferably 7 parts by weight, more preferably 0.3 to 3 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. Moreover, it is preferable that it is 0.01-100 weight part with respect to a total of 100 weight part of a monofunctional aromatic compound (B) and a polyfunctional unsaturated compound (C), More preferably, it is 0.1-100 weight part. 20 parts by weight, particularly preferably 1 to 12 parts by weight.

  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 from the viewpoint of improving the adhesion to the substrate and the reactivity with the base polymer.

  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.

  The content of the crosslinking agent (E) is usually preferably 0.01 to 10 parts by weight with respect to 100 parts by weight in total of the acrylic resin (A1) and the acrylic resin (A2). More preferably, it is 0.05-5 weight part, Most preferably, it is 0.1-2 weight part. 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 γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropyldimethoxymethylsilane.

  As content of a silane coupling agent (F), it is 0.001-10 weight part normally with respect to a total of 100 weight part of the said acrylic resin (A1) and acrylic resin (A2), Preferably 0.01 to 1 part by weight, particularly preferably 0.03 to 0.8 part 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 pressure-sensitive adhesives, urethane resin, rosin, rosin ester, hydrogenated rosin ester, phenolic resin, aromatic, as long as the effects of the present invention are not impaired. Modified terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, styrene resins, xylene resins, and other tackifiers, colorants, fillers, anti-aging agents, ultraviolet absorbers, functional dyes, etc. Known additives and compounds that cause coloration or discoloration upon 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. Such aging treatment is performed to balance the physical properties of the adhesive. As aging conditions, the temperature is usually from room temperature to 70 ° C., and the time is usually from 1 day to 30 days. 1 to 20 days at ℃, 3 to 10 days at 23 ℃, 40
What is necessary is just to carry out on conditions, such as 1 day-7 days at ° C.

  When applying the pressure-sensitive adhesive composition [I], it is preferable to dilute the pressure-sensitive adhesive composition [I] in a solvent, and the dilution concentration is preferably 5 to 60% by weight, particularly preferably 10%. ~ 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.

  About the gel fraction of the adhesive layer manufactured by the said method, it is preferable that it is 30 to 90% from the point of durability and light leakage prevention performance, and 60 to 85% is especially preferable. 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 optical member in the present invention is not particularly limited, and an optical film suitably used for an image display device such as a liquid crystal display device, an organic EL display device, or a PDP, such as a polarizing plate, a retardation plate, or an elliptical polarizing plate. , Optical compensation films, brightness enhancement films, and those in which these are laminated. 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.

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 (A1-1)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 1.5 parts of 2-hydroxyethyl acrylate (a1), 98.5 parts of butyl acrylate (a2), and First, 120 parts of ethyl acetate and 45 parts of acetone were added. After heating and refluxing, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and the reaction was performed at ethyl acetate reflux temperature for 3 hours. Diluted acrylic resin (A1-1) solution (weight average molecular weight (Mw) 1,500,000, dispersity (Mw / Mn) 3.4, glass transition temperature -53 ° C., solid content 23%, viscosity 8000 mPa · s ( 25 ° C.).

[Acrylic resin (A2-1)]
In a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, acrylic acid (a1 ′) 5 parts, butyl acrylate (a′2) 95 parts, and ethyl acetate 120 parts , 45 parts of acetone was added, and after heating to reflux, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, reacted for 3 hours at the reflux temperature of ethyl acetate, diluted with ethyl acetate and acrylic. Resin (A2-1) solution (weight average molecular weight (Mw) 1,500,000, dispersity (Mw / Mn) 3.4, glass transition temperature -53 ° C., solid content 23%, viscosity 8000 mPa · s (25 ° C.)) Got.

[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, 1.5 parts of 2-hydroxyethyl acrylate, 98 parts of butyl acrylate, 0.5 part of acrylic acid and ethyl acetate 85 parts and 45 parts of acetone were added, and after heating and refluxing was started, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, reacted at ethyl acetate reflux temperature for 3 hours, and then diluted with ethyl acetate. Acrylic resin (A′-1) solution (weight average molecular weight (Mw) 1.7 million, dispersity (Mw / Mn) 3.4, glass transition temperature −53 ° C., solid content 17%, viscosity 8000 mPa · s (25 ° C)).

（注）ＢＡ：ブチルアクリレート
ＨＥＡ：２−ヒドロキシエチルアクリレート
ＡＡｃ：アクリル酸
表中「---」は配合しなかったことを表す

(Note) BA: Butyl acrylate
HEA: 2-hydroxyethyl acrylate AAc: Acrylic acid In the table, “---” indicates that it was not blended.

[Monofunctional aromatic compound (B)]
The following were prepared as the monofunctional aromatic compound (B-1).
Phenyl diethylene glycol acrylate (manufactured by Kyoeisha, trade name “Light acrylate P2HA”: molecular weight 236.3) Flash point 165 ° C., volatile residue 100%
The following were prepared as the monofunctional aromatic compound (B-2).
Ethoxylated orthophenylphenol acrylate (manufactured by Hitachi Chemical Co., Ltd., trade name “FA-301A”: molecular weight 268 flash point 170-199 ° C., volatile residue 100%

[Polyfunctional unsaturated compound (C)]
The following were prepared as the polyfunctional unsaturated compound (C-1).
・ Trimethylolpropane triacrylate (molecular weight 296.3)

[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, 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.

Then, the pressure-sensitive adhesive composition solution obtained above is applied to a polyester release sheet so that the thickness after drying is 25 μm, and dried at 90 ° C. for 3 minutes to form a pressure-sensitive adhesive composition layer. It was.
In Examples 1 and 2 and Comparative Examples 2 to 4, the obtained pressure-sensitive adhesive composition layer was transferred onto a polyethylene terephthalate (PET) film (thickness 38 μm), and an electrodeless lamp manufactured by Fusion Co., Ltd. [H bulb of LH6UV lamp] At a peak illuminance of 600 mW / cm ² and an integrated exposure dose of 240 mJ / cm ² (120 mJ / cm ² × 2 passes), 23 ° C. × 50% R.D. H. The film was aged for 10 days under the above conditions to obtain a PET film with an adhesive layer.
In Comparative Example 1, the obtained pressure-sensitive adhesive composition layer was transferred onto a polyethylene terephthalate (PET) film (thickness 38 μm), and 23 ° C. × 50% R.D. H. The film was aged for 10 days under the above conditions to obtain a PET film with an adhesive layer.

  Using the PET film with the pressure-sensitive adhesive layer thus obtained, the gel fraction was measured and evaluated according to each method shown below. These results are also shown in Table 2 below.

[Gel fraction]
After the obtained PET film with the pressure-sensitive adhesive layer is cut into 40 × 40 mm, the release sheet is peeled off and the pressure-sensitive adhesive layer side is bonded to a 50 × 100 mm SUS mesh sheet (200 mesh), and then the SUS mesh sheet. The sample was wrapped from the center with respect to the longitudinal direction, and the sample was wrapped. Then, the gel fraction was measured by weight change when immersed in a sealed container containing 250 g of toluene.

注）・（Ａ）〜（Ｆ）における表中の（ ）内の数値は配合重量部である。
・表中「---」は配合しなかったことを表す

Note) · The numerical value in () in the table in (A) to (F) is the weight part.
・ "---" in the table indicates that it was not blended

Next, the said adhesive composition solution was apply | coated to the polyester-type release sheet so that the thickness after drying might be set to 25 micrometers, and it dried at 90 degreeC for 3 minute (s), and formed the adhesive composition layer.
In Examples 1 and 2 and Comparative Examples 2 and 3, the obtained pressure-sensitive adhesive composition layer was transferred onto a polarizing plate (thickness 190 μm), and peak illuminance was measured with an electrodeless lamp [H bulb of LH6UV lamp] manufactured by Fusion. : 600 mW / cm ² , integrated exposure: 240 mJ / cm ² , ultraviolet irradiation (120 mJ / cm ² × 2 passes), 23 ° C. × 50% R.D. H. The film was aged for 10 days under the above conditions to obtain a polarizing plate with an adhesive layer.
In Comparative Example 1, the obtained pressure-sensitive adhesive composition layer was transferred onto a polarizing plate (thickness 190 μm), and 23 ° C. × 50% R.D. H. The film was aged for 10 days under the above conditions to obtain a polarizing plate with an adhesive layer.
In addition, “MLP38U” manufactured by Biei Imaging Co., Ltd. was used as the polarizing plate, and the polarizing plate was cut at 45 ° C. 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) and reworkability (adhesion strength measurement) were measured and evaluated according to the following methods. . These results are also shown in Table 3 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. After that, autoclaving (50 ° C., 0.5 MPa, 20 minutes) is performed, and then foaming and peeling are evaluated in the following durability tests (1) to (4) (moisture and heat resistance test, heat cycle test, heat resistance test). Was done. Furthermore, in the heat resistance test of (4) below, in addition to the evaluation of foaming and peeling, a sample for light leakage observation was prepared by bonding the same sample on both the front and back surfaces so that the polarizing plate became crossed Nicol. The light leakage phenomenon was also evaluated.
In addition, the used test piece size was punched into 20 cm × 15 cm.

[Durability test]
(1) Moisture and heat resistance test 60 ° C., 90% R.D. H. Endurance test for 150 hours (2) Heat cycle test Endurance test for 75 cycles with the operation of leaving at -35 ° C for 60 minutes and then at 70 ° C for 60 minutes (3) Heat resistance test (A)
Durability test at 90 ° C for 150 hours (4) Heat resistance test (B)
80 ° C, 150 hours durability test and light leakage

[Evaluation criteria]
(Foam)
○: Foam is hardly seen △ ... Foam is slightly seen × ... Foam is seen a lot (peeling)
○: Peeling less than 0.5 mm, or occurrence of a lift mark less than 0.5 mm Δ: Peeling of 0.5 mm or more and less than 10 mm, or 0.5 mm or more
Occurrence of a float of less than 10 mm × Peeling of 10 mm or more, or generation of a float of 10 mm or more (light leakage)
◎ ・ ・ ・ There is almost no light leakage ○ ・ ・ ・ Slight leakage occurs △ ・ ・ ・ Slight leakage occurs × ・ ・ ・ Large light leakage occurs on 4 sides

[Rework performance]
・ Measurement of adhesive strength About polarizing plate with adhesive layer, cut to 25mm width, peel off release film, and press adhesive layer side against non-alkali glass plate (Corning, “Corning 1737”). The polarizing plate and the glass plate were bonded together. Thereafter, after autoclaving (50 ° C., 0.5 MPa, 20 minutes), the initial adhesive strength was 23 ° C. and 50% R.D. H. After being left for 24 hours, the adhesive strength after standing for 2 days at 50 ° C. was measured in a 180 ° C. peel test.
・ Evaluation ○ ・ ・ ・ Initial adhesive strength is 10 N / 25 mm or less, and temporal adhesive strength is 20 N / 25 mm or less, and there is no adhesive residue × ・ ・ ・ Initial adhesive strength is greater than 10 N / 25 mm, or temporal adhesive strength Is larger than 20N / 25mm or there is adhesive residue

※１剥離のため観察できず
※２一部凝集破壊のため糊残りあり

* 1 Cannot be observed due to peeling * 2 There is adhesive residue due to partial cohesive failure

  The pressure-sensitive adhesives of the examples were excellent in a good balance at a high level in rework performance (reattachability), durability, and optical characteristics (light leakage resistance) when the polarizing plate and the glass substrate were bonded together. On the other hand, Comparative Examples 1 to 3 did not satisfy the required performance in the following points.

-Although the adhesive of the comparative example 1 contains a hydroxyl-containing acrylic resin (A1), it does not contain a carboxyl group-containing acrylic resin (A2) and a monofunctional unsaturated compound (B). Is a pressure-sensitive adhesive obtained by curing, and has good durability and rework performance, but poor light leakage resistance.
The pressure-sensitive adhesive composition of Comparative Example 2 contains a hydroxyl group-containing acrylic resin (A1) and a monofunctional unsaturated compound (B), but does not contain a carboxyl group-containing acrylic resin (A2). Is a pressure-sensitive adhesive obtained by curing by active energy ray irradiation, and has good rework performance and light leakage resistance, but is inferior in durability.
-The adhesive of Comparative Example 3 was obtained by curing an adhesive composition containing an acrylic resin containing both a hydroxyl group and a carboxyl group and a monofunctional unsaturated compound (B) by irradiation with active energy rays. It is an adhesive and has good durability and light leakage resistance, but is inferior to rework performance.

  By using the pressure-sensitive adhesive of the present invention, the optical laminate, particularly an optical member such as a polarizing plate, is excellent in rework performance between the glass substrate and the adhesive layer between the pressure-sensitive adhesive layer and the glass substrate even in a high temperature and high humidity environment. In this way, it is possible to obtain a liquid crystal display device in which no foaming or peeling occurs and color unevenness or light leakage does not occur. Therefore, it is particularly effective as an adhesive for optical members, and is very useful as an adhesive for obtaining an optical member with an adhesive layer and an image display device obtained by using them.

Claims (10)

Acrylic resins containing a hydroxyl group in a side chain (A1), acrylic resin containing a carboxyl group in the side chain (A2), aromatic compounds containing a single error ethylenic unsaturated group (B), ethylenically unsaturated The pressure-sensitive adhesive composition [I] containing the ethylenically unsaturated compound (C) containing two or more saturated groups and the crosslinking agent (E) is crosslinked by the crosslinking agent, and has active energy rays and / or heat. The acrylic resin (A1) containing a hydroxyl group in the side chain contains a hydroxyl group-containing monomer (a1) and a copolymer component substantially free of a carboxyl group-containing monomer. An acrylic resin obtained by polymerization, wherein the acrylic resin (A2) containing a carboxyl group in the side chain contains a carboxyl group-containing monomer (a′1) and a hydroxyl group-containing monomer. An acrylic resin obtained by copolymerizing a copolymer component that does not react, and the aromatic compound (B) containing one ethylenically unsaturated group is easily reactive with the acrylic resin (A) or the crosslinking agent (E). A pressure-sensitive adhesive , which is an aromatic compound containing no group, and the crosslinking agent (E) contains an isocyanate-based crosslinking agent.   The pressure-sensitive adhesive according to claim 1, wherein the ratio (molar ratio) between the hydroxyl group and the carboxyl group contained in the pressure-sensitive adhesive composition [I] is hydroxyl group / carboxyl group = 0.15 to 20.   The blending ratio (weight ratio) of the acrylic resin (A1) containing a hydroxyl group in the side chain and the acrylic resin (A2) containing a carboxyl group in the side chain is (A1) :( A2) = 50: 50 to 95: The pressure-sensitive adhesive according to claim 1, wherein the pressure-sensitive adhesive is 5. Adhesive composition [I] contains a polymerization initiator (D), The adhesive in any one of Claims 1-3 characterized by the above-mentioned. The pressure-sensitive adhesive according to any one of claims 1 to 4 , wherein the crosslinking agent (E) is an aromatic polyvalent isocyanate-based crosslinking agent. The pressure-sensitive adhesive for an optical member characterized by using an adhesive in accordance with claim 1-5. The pressure-sensitive adhesive for optical members according to claim 6, wherein the optical member is a polarizing plate. An optical member with a pressure-sensitive adhesive layer, comprising a laminated structure of a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive for optical members according to claim 6 or 7 and an optical member. An image display device using the optical member with an adhesive layer according to claim 8 . Acrylic resins containing a hydroxyl group in a side chain (A1), acrylic resin containing a carboxyl group in the side chain (A2), aromatic compounds containing a single error ethylenic unsaturated group (B), ethylenically unsaturated An acrylic resin (A1) containing an ethylenically unsaturated compound (C) containing two or more saturated groups and a crosslinking agent (E) and containing a hydroxyl group in the side chain contains a hydroxyl group-containing monomer (a1). And an acrylic resin obtained by copolymerizing a copolymer component that does not substantially contain a carboxyl group-containing monomer, and the acrylic resin (A2) containing a carboxyl group in the side chain is a carboxyl group-containing monomer (a′1). ) And a copolymer component that does not contain a hydroxyl group-containing monomer, and an aromatic compound (B) containing one ethylenically unsaturated group is An aromatic compound containing no Lil-based resin (A) and crosslinking agent (E) and reaction tends functional group, active energy ray-curable pressure-sensitive cross-linking agent (E) is characterized by comprising an isocyanate-based crosslinking agent Agent composition.