WO2011090090A1

WO2011090090A1 - Adhesive agent, adhesive agent for optical member, optical member having adhesive layer attached thereto, image display device, active-energy-ray- and/or heat-curable adhesive agent composition, and adhesive agent composition

Info

Publication number: WO2011090090A1
Application number: PCT/JP2011/050916
Authority: WO
Inventors: 秀昭鈴木; 聖子 ▲高▼木; 直也三ツ谷; 浩史堀家
Original assignee: 日本合成化学工業株式会社
Priority date: 2010-01-21
Filing date: 2011-01-20
Publication date: 2011-07-28
Also published as: TWI494403B; CN104046281A; CN104046281B; CN102639663B; KR101766934B1; KR20120124394A; CN102639663A; TW201134905A

Abstract

Disclosed is an adhesive agent produced by curing an adhesive agent composition [I] with an active energy ray and/or heat, wherein the adhesive agent composition [I] comprises an acrylic resin (A), an aromatic compound (B) having one ethylenically unsaturated group, and an ethylenically unsaturated compound (C) having at least two ethylenically unsaturated groups, and wherein the adhesive agent is characterized in that the content of the component (B) is 3 to 300 parts by weight relative to 100 parts by weight of the component (A) and the ratio (mol%) of the content of the component (B) to the total content of the components (B) and (C) is more than 50 mol%. The adhesive agent enables the production of a liquid crystal display device in which an adhesive layer produced by curing the adhesive agent with an active energy ray and/or heat can have excellent handling properties (tack) and optical properties (haze), an optical laminate (particularly an optical member such as a polarizing plate) can be adhered to a glass substrate satisfactorily under high-temperature high-humidity environments, no foaming or detachment occurs between the adhesive agent layer and the glass substrate, and unevenness in color or leakage of light does not occur.

Description

Adhesive, adhesive for optical member, optical member with adhesive layer, image display device, active energy ray and / or thermosetting adhesive composition, adhesive composition

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, an active energy ray and / or a thermosetting pressure-sensitive adhesive composition. About. 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 sides of a polyvinyl alcohol polarizer are sandwiched between triacetyl cellulose 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 acrylic adhesive does not increase and the durability of liquid crystal display devices There was a problem that the sex became 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-linking 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 drops and the tackiness when the pressure-sensitive adhesive is bonded to the adherend is reduced. There was a problem of being bad.

Therefore, in the present invention, under such a background, the pressure-sensitive adhesive layer is an adhesive having excellent handleability (tack) and optical characteristics (haze), and an optical member such as a polarizing plate is bonded to a glass substrate or the like. The purpose of the present invention is to provide an adhesive having excellent durability and optical properties (light leakage resistance), 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. A monofunctional monomer containing a monofunctional monomer and a polyfunctional monomer containing two or more ethylenically unsaturated groups at a specific ratio such that the monofunctional monomer is a main component, and further having an aromatic ring as the monofunctional monomer By using it, it found out that it was excellent in handleability (tack) and optical characteristics (haze), and was excellent in balance between durability and light leakage resistance, and completed the present invention.

That is, the gist of the present invention is that an acrylic resin (A), an aromatic compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated compound containing two or more ethylenically unsaturated groups ( The pressure-sensitive adhesive composition [I] containing C) is a pressure-sensitive adhesive that is cured by active energy rays and / or heat, and the content of the aromatic compound (B) is 100 weights of the acrylic resin (A). 3 to 300 parts by weight, and the content (mol%) of the aromatic compound (B) with respect to the total amount of the aromatic compound (B) and the ethylenically unsaturated compound (C) is more than 50 mol% The present invention relates to an adhesive having a large size.
Further, the gist of the present invention is an optical member-containing pressure-sensitive adhesive using the above-mentioned pressure-sensitive adhesive, a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive for optical members, and an optical member with a pressure-sensitive adhesive layer including a laminated structure of the optical members, and the like. The present invention relates to an image display device made of an optical member.
In addition, the gist of the present invention is an acrylic resin (A), a polymer of an aromatic compound (B) containing one ethylenically unsaturated group, and an aromatic compound (B) containing one ethylenically unsaturated group. ) And an organic solvent.
Furthermore, the gist of the present invention is that the acrylic resin (A), the aromatic compound (B) containing one ethylenically unsaturated group, and the ethylenic unsaturated containing two or more ethylenically unsaturated groups. It contains the compound (C), the acrylic resin (A) has a negative photoelastic coefficient, and the cured product of the aromatic compound (B) and the ethylenically unsaturated compound (C) has a positive photoelastic coefficient. It is related with the adhesive composition characterized by these.

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, the birefringence derived from the acrylic polymer is estimated to be 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, a cured product of an aromatic compound (B) and an ethylenically unsaturated compound (C) that generate positive birefringence compared to the conventional acrylic resin (A) that generates negative birefringence. Are uniformly mixed, the birefringence of the acrylic resin (A) and / or the birefringence of the triacetyl cellulose film is caused by the cured product of the aromatic compound (B) and the ethylenically unsaturated compound (C). By offsetting, a polarizing plate with an adhesive layer having excellent light leakage resistance could be obtained.

On the other hand, it is important for this purpose that the aromatic compound (B) that is monofunctional and capable of generating positive birefringence is more than the ethylenically unsaturated compound (C). The cured product of the unsaturated compound (C) exhibits a degree of freedom, and the cured product of the aromatic compound (B) and the ethylenically unsaturated compound (C) is also aligned when the acrylic resin (A) is aligned. It is estimated that the effect of the present invention can be achieved.
On the other hand, when the amount relationship between the aromatic compound (B) and the ethylenically unsaturated compound (C) is reversed, the cured product has a large number of branched structures, and the degree of freedom in the structure is lost, causing orientation. It will be difficult to achieve the effects of the present invention.

The pressure-sensitive adhesive of the present invention can be suitably used particularly as an optical member, and the pressure-sensitive adhesive layer after curing with active energy rays and / or heat is excellent in handleability (tack) and optical properties (haze). Even under high-temperature and high-humidity environments, it has excellent adhesion between optical laminates, especially optical members such as polarizing plates, and glass substrates, and foaming or peeling occurs between the pressure-sensitive adhesive layer and the glass substrate. Therefore, a liquid crystal display device in which uneven color and light leakage do 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 includes an acrylic resin (A), an aromatic compound (B) containing one ethylenically unsaturated group, and an ethylenic group containing two or more ethylenically unsaturated groups. It contains an unsaturated compound (C).

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

In such a (meth) acrylic acid alkyl ester monomer (a1), 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 (meth) a Relate and the like. These can be used alone or in combination of two or more.

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

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

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

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

Among the above hydroxyl group-containing monomers, a primary hydroxyl group-containing monomer is preferable in terms of excellent reactivity with the crosslinking agent (E), and the content ratio of di (meth) acrylate as an impurity is 0.5% or less. Preferably, 0.2% or less, particularly 0.1% or less is preferably used. Specifically, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are preferable.

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

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

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

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

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

The content in the case of copolymerizing the functional group-containing monomer (a2) is preferably 0 to 30% by weight, particularly preferably 0.1 to 10% by weight, more preferably 0. If the content of the functional group-containing monomer (a2) is too large, the viscosity tends to increase or the stability of the resin tends to decrease.

Other copolymerizable monomers (a3) include, for example, phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) ) Monomers containing one aromatic ring such as acrylate, styrene, α-methylstyrene; monomers containing biphenyl groups such as biphenyl acrylate, biphenyloxyethyl (meth) acrylate, biphenyloxyalkyl (meth) acrylate, 2-methoxy Ethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-butoxydiethylene glycol ( ) Alkoxy groups such as acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, and oxyalkylene Group-containing monomers: alkoxyalkyl (meth) such as methoxymethyl (meth) acrylamide, ethoxymethyl (meth) acrylamide, propoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, isobutoxymethyl (meth) acrylamide, etc. Acrylamide monomers; (meth) acryloylmorpholine, dimethyl (meth) acrylamide, diethyl (meth) Acrylamide, (meth) acrylamide N- methylol (meth) acrylamide, (meth) acrylamide monomer; acrylonitrile, methacrylonitrile, vinyl acetate, and the like.

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

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

The acrylic resin (A) is produced by polymerizing the monomer components (a1) to (a3). In such polymerization, conventional methods such as solution radical polymerization, suspension polymerization, bulk polymerization, and emulsion polymerization are used. It can be performed by a known method. For example, a polymerization monomer such as a (meth) acrylic acid alkyl ester monomer (a1), a functional group-containing monomer (a2), another copolymerizable monomer (a3), or a polymerization initiator is mixed or dropped in an organic solvent. The polymerization is carried out at reflux or at 50 to 90 ° C. for 2 to 20 hours.

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

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

The weight average molecular weight of the acrylic resin (A) is usually 100,000 to 3,000,000, preferably 300,000 to 2,500,000, particularly preferably 600,000 to 2,000,000, particularly preferably 1,000,000 to 1,800,000. When the weight average molecular weight is too small, the durability performance tends to be lowered. When the weight average molecular weight is too large, a large amount of a diluent solvent is required, which tends to be undesirable in terms of coating property and cost.

The degree of dispersion (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 20 or less, particularly preferably 10 or less, more preferably 7 or less, and particularly preferably 4 or less. preferable. When the degree of dispersion is too high, the durability performance of the pressure-sensitive adhesive layer is lowered, and foaming or the like tends to occur. The lower limit of the degree of dispersion is usually 2 from the viewpoint of production limit.

Furthermore, the glass transition temperature of the acrylic resin (A) is preferably −80 to −20 ° C., particularly preferably −75 to −30 ° C., more preferably −60 to −40 ° C., and the glass transition temperature is too high. When the adhesive strength is too low, the heat resistance tends to decrease.

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 number average molecular weight can also be used in the same manner. 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 Fox equation.

In the present invention, the acrylic resin (A) contains a hydroxyl group-containing acrylic resin (A1) and a side chain contains a carboxyl group in terms of satisfying a good balance between durability and light leakage suppression. It is also preferable to use the acrylic resin (A2) used together.

The acrylic resin (A1) containing a hydroxyl group in the side chain (hereinafter sometimes abbreviated as “acrylic resin (A1)”) may be any acrylic resin containing a hydroxyl group in the side chain. Manufactured by copolymerizing a hydroxyl group-containing monomer, reacting a functional group of an acrylic resin containing a functional group with a compound having both a functional group capable of reacting with the functional group and a hydroxyl group (post-modification) What is done.

Among these, an acrylic resin containing a hydroxyl group in the side chain can be used when industrially produced by copolymerizing a copolymer component containing a hydroxyl group-containing monomer with another copolymer component. (A1) is preferable in that it is obtained, and the acrylic resin (A1) is obtained by using a hydroxyl group-containing monomer as an essential component as the functional group-containing monomer (a2) constituting the acrylic resin (A) described above. .

The acrylic resin (A1) preferably contains substantially no carboxyl group-containing monomer as a copolymer component other than the hydroxyl group-containing monomer, and further contains substantially no other functional group-containing monomer other than the carboxyl group. It is preferable. “Substantially free” means that the content of the monomer is 1% by weight or less, preferably 0.1% by weight or less, particularly preferably not contained.

The acrylic resin (A2) containing a carboxyl group in the side chain (hereinafter may be abbreviated as “acrylic resin (A2)”) may be any acrylic resin containing a carboxyl group in the side chain. For example, a method of copolymerizing a carboxyl group-containing monomer, a method of reacting (post-modifying) a compound having both a functional group capable of reacting with the functional group and a carboxyl group on the functional group of the acrylic resin containing the functional group And the like manufactured by the above.

Among these, acrylics containing a carboxyl group in the side chain can be used easily when industrially produced by copolymerizing a copolymer component containing a carboxyl group-containing monomer with another copolymer component. It is preferable in that an acrylic resin (A2) is obtained, and the acrylic resin (A2) uses a carboxyl group-containing monomer as an essential component as the functional group-containing monomer (a2) constituting the acrylic resin (A) described above. Is obtained.

The acrylic resin (A2) preferably contains substantially no hydroxyl group-containing monomer as a copolymer component other than the carboxyl group-containing monomer, and further contains substantially no other functional group-containing monomer other than the carboxyl group. It is preferable. “Substantially free” means that the content of the monomer is 1% by weight or less, preferably 0.1% by weight or less, particularly preferably not contained.

When the acrylic resin (A1) and the acrylic resin (A2) are used in combination, the difference in weight average molecular weight between the acrylic resin (A1) and the acrylic resin (A2) is small. This is preferable because the durability of the network can be improved by increasing the cohesive force of the network. Specifically, the ratio of the weight average molecular weight of the acrylic resin (A1) to the acrylic resin (A2) ((A1) / (A2 )) Is preferably (A1) / (A2) = 0.5 to 1.5, more preferably (A1) / (A2) = 0.8 to 1.2, still more preferably (A1). /(A2)=0.9 to 1.1.

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.

Here, the content ratio (molar ratio) of the hydroxyl group to 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 relative to the carboxyl group is too large, the gel fraction greatly increases depending on the amount of the crosslinking agent added, and the durability and light leakage resistance tend to decrease. There is a tendency for power 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 be a hydroxyl group derived from a carboxyl group or a carboxyl group, and may be within the above range in the pressure-sensitive adhesive composition [I].

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 hardening by heat.

The number of aromatic rings contained in the monofunctional aromatic compound (B) may be one or a plurality of aromatic rings, but one aromatic ring may be included in order to balance the adhesive properties. A compound containing two aromatic rings is preferable from the viewpoint of efficiently controlling the refractive index and birefringence of the adhesive layer.

Specific examples of the monofunctional aromatic compound (B) include ether-based monofunctional aromatic compounds (b1), ester-based monofunctional aromatic compounds (b2), and the like. Examples of the monofunctional aromatic compound (b1) include dihydroxybenzene derivatives such as phenol derivatives, catechol, resorcinol, and hydroquinone. Examples of the ester-based monofunctional aromatic compound (b2) include benzoic acid derivatives. And phthalic acid derivatives.

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

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

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

Specific examples of the above (b1-1) include, for example, phenoxyethyl (meth) acrylate, phenyldiethylene glycol (meth) acrylate, phenyltriethylene glycol (meth) acrylate, phenyltetraethylene glycol (meth) acrylate, and phenyloctaethylene glycol. Phenyl polyethylene glycol (meth) acrylate, phenoxypropyl (meth) acrylate, phenyldipropylene glycol (meth) acrylate, phenyl polypropylene having an ethylene glycol structure repeating number of 2 to 8 (preferably 2 to 4) such as (meth) acrylate Glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, ethoxylated phenylphenyl (meth) acrylate, Nonylphenyl polyethylene glycol (meth) acrylate having 2 to 8 (preferably 2 to 4) ethylene glycol structures such as ruphenoxyethyl (meth) acrylate and nonylphenyldiethylene glycol (meth) acrylate, and nonylphenoxypropyl (meth) Nonylphenyl polypropylene glycol (meth) acrylates having a repeating number of propylene glycol structures of 2 to 8 (preferably 2 to 4) such as acrylate and nonylphenyldipropylene glycol (meth) acrylate are listed. Polyethylene glycol acrylate (trade name “Biscoat # 193” manufactured by Osaka Organic Chemical Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (trade name “Biscoat” manufactured by Osaka Organic Chemical Co., Ltd.) 220 "), phenoxydiethylene glycol acrylate (manufactured by Kyoeisha, trade name" light acrylate P2HA "), phenyltriethylene glycol acrylate (trade name" phenoxytriethylene glycol acrylate ", manufactured by Hitachi Chemical Co., Ltd.) Product name "Phenoxytetraethylene glycol acrylate") (Hitachi Chemical Co., Ltd., trade name "Nonylphenoxyethyl acrylate"), Nonylphenyl diethylene glycol acrylate (Hitachi Chemical Co., Ltd., trade name "Nonylphenoxydiethylene glycol acrylate"), Nonylphenyltetraethylene glycol acrylate (manufactured by Hitachi Chemical Co., Ltd., trade name “nonylphenoxytetraethylene glycol acrylate”), noni Ruphenyloctaethylene glycol acrylate (trade name “nonylphenoxyoctaethylene glycol acrylate” manufactured by Hitachi Chemical Co., Ltd.), nonylphenyl polypropylene glycol (meth) acrylate (trade name “nonylphenoxy polypropylene glycol (meth) acrylate” manufactured by Hitachi Chemical Co., Ltd.) ), Ethoxylated o-phenylphenyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester 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-acryloyloxyethyl-2-hydroxypropyl phthalate (trade name “Biscoat # 2311HP” manufactured by Osaka Organic Chemical Co., Ltd.), 2-acryloyloxyethyl hydrogen as commercially available products. Phthalate (trade name “Biscoat # 2000” manufactured by Osaka Organic Chemical Co., Ltd.), 2-acryloyloxypropyl hydrogen phthalate (trade name “Biscoat # 2100” manufactured by Osaka Organic Chemical Co., Ltd.), 2-methacryloyloxyethylphthalic acid (new) Nakamura Chemical Co., Ltd., trade name “CB-1”).

The monofunctional aromatic compound (B) used in the present invention is not particularly limited as long as it is a compound having an aromatic ring and one ethylenically unsaturated group in the molecule as described above. In particular, those containing two or more aromatic rings, sulfur atoms or bromine atoms are particularly preferred.
Aromatic rings, sulfur atoms, and bromine atoms are known as structures that have a very high refractive index and are easy to introduce into acrylic monomers. These structures are the side chains of acrylic resins (preferably the main chain on the side chain). By entering the position further away from the chain), the refractive index on the tensile direction side (x-axis side) of the birefringent component generated when stress is applied to the entire acrylic pressure-sensitive adhesive layer is very efficiently increased. be able to.
As a result, in the pressure-sensitive adhesive composed of the total of the alkyl (meth) acrylate-based acrylic resin that increases the refractive index in the direction perpendicular to the tension (y-axis side) and the polymer of the monofunctional compound (B). As a result, the birefringence of the pressure-sensitive adhesive layer is offset, so that the pressure-sensitive adhesive layer hardly generates birefringence, and light leakage can be efficiently suppressed.

Monofunctional aromatic compound (B) contains a structural site satisfying the condition of “containing at least two aromatic rings, sulfur atoms, or bromine atoms” as a biphenyl structure, a naphthalene structure, an anthracene structure, a phenylthio structure, Among them, a biphenyl structure and a phenylthio structure are preferable in terms of efficiently giving a positive birefringence increasing effect.

Specific examples of the monofunctional aromatic compound (B) include a biphenyl structure-containing (meth) acrylate compound, a phenylthio structure-containing (meth) acrylate compound, a naphthalene structure-containing (meth) acrylate compound, and a bromophenyl structure. Examples thereof include a (meth) acrylate-based compound.

Such biphenyl structure-containing (meth) acrylate compounds include biphenyl (meth) acrylate, biphenyloxyalkyl (meth) acrylate, and biphenyl polyalkylene glycol (meth) acrylate.

Examples of such biphenyloxyalkyl (meth) acrylates include biphenyloxyalkyl (meth) acrylates having an alkyl group having 1 to 8 carbon atoms. Specifically, biphenyloxymethyl (meth) acrylate, biphenyloxyethyl (meta) ) Acrylate, biphenyloxypropyl (meth) acrylate, and the like.

Examples of such biphenyl polyalkylene glycol (meth) acrylates include biphenyl polyalkylene glycol (meth) acrylates in which the alkylene group has 1 to 8 carbon atoms and the alkylene glycol chain has 2 to 10 repeating units. , Biphenyldiethylene glycol (meth) acrylate, biphenyltriethylene glycol (meth) acrylate, biphenyltetraethylene glycol (meth) acrylate, biphenyldipropylene glycol (meth) acrylate, biphenyl polyethylene glycol (meth) acrylate, biphenyl polypropylene glycol (meth) acrylate Etc.

Among these, biphenyl polyalkylene glycol (meth) acrylate is preferable, particularly preferably biphenyl polyethylene glycol (meth) acrylate in terms of efficiently providing a positive photoelastic effect, and more preferably the number of repeating units of ethylene glycol chain. Is 1 to 4 biphenyl polyethylene glycol (meth) acrylate.

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

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

Such bromophenyl structure-containing (meth) acrylates include bromophenoxymethyl (meth) acrylate, dibromophenoxymethyl (meth) acrylate, tribromophenoxymethyl (meth) acrylate, tetrabromophenoxymethyl (meth) acrylate, and pentabromophenoxymethyl. (Meth) acrylate, bromophenoxyethyl (meth) acrylate, dibromophenoxyethyl (meth) acrylate, tribromophenoxyethyl (meth) acrylate, tetrabromophenoxyethyl (meth) acrylate, pentabromophenoxyethyl (meth) acrylate, bromophenoxy Propyl (meth) acrylate, dibromophenoxypropyl (meth) acrylate, tribromophenoxypropyl (meth) a Relate, tetrabromo-phenoxypropyl (meth) acrylate, phenoxyalkyl (meth) acrylate benzene ring is substituted with 1 to 5 bromine atoms, such as penta-bromo-phenoxypropyl (meth) acrylate.
The alkyl group usually has 1 to 12 carbon atoms.

In addition, as a monofunctional aromatic compound (B), it is contained in the crosslinked network of acrylic resin (A) that it does not contain the functional group which reacts easily with acrylic resin (A) or a crosslinking agent (E). Thus, the degree of freedom of the cured product of the monofunctional aromatic compound (B) and the ethylenically unsaturated compound (C) is lost, which is preferable in that the possibility that the light leakage resistance improving effect is reduced is small.

Among the monofunctional aromatic compounds (B) described above, phenyl polyethylene glycol acrylate (polyethylene glycol having 2 to 4 repeating units), nonylphenoxyethyl acrylate, nonylphenyl polyethylene glycol acrylate (repeating polyethylene glycol) is particularly preferable. 2-4), nonylphenoxypropylene glycol acrylate, nonylphenyl polypropylene glycol acrylate (2-4 repeat units of polypropylene glycol), biphenyloxyethyl acrylate, biphenyl polyethylene glycol (meth) acrylate (polyethylene glycol repeat units) The number is 2-4).

Specifically, such functional groups are any one and / or two or more of an isocyanate group, a hydroxyl group and a carboxyl group.

The weight average 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 weight average molecular weight is too large, the birefringence tends to be difficult to adjust due to a decrease in the aromatic ring concentration.If the weight average molecular weight is too small, it tends to volatilize when the pressure-sensitive adhesive is dried, and the effect of the invention tends to be difficult to obtain. is there.

The monofunctional aromatic compound (B) preferably has a flash point of 120 ° 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 phenyldiethylene glycol acrylate (flash point: 165 ° C.), ethoxylated orthophenylphenol acrylate (flash point: 170 to 199 ° C.), and the like. [<Reference value>, phenoxyethyl acrylate (flash point: 139 to 141 ° C.), benzyl acrylate (flash point: 107 ° C.)]

The content of the monofunctional aromatic compound (B) needs to be 3 to 300 parts by weight, preferably 5 to 100 parts by weight, more preferably 100 parts by weight of the acrylic resin (A). Is 8 to 60 parts by weight, particularly preferably 25 to 45 parts by weight. If the content of the monofunctional aromatic compound (B) is too large, both durability and light leakage resistance tend to deteriorate, and if too small, the light leakage resistance tends to decrease.

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

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

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 Penta (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 desirably 0.01 to 30 parts by weight, preferably 0.5 to 10 parts by weight, with respect to 100 parts by weight of the acrylic resin (A). More preferably, it is 1 to 5 parts by weight. 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 (mol%) of the monofunctional aromatic compound (B) with respect to the total amount of the polyfunctional unsaturated compound (C) needs to be larger than 50 mol%, preferably more than 50 mol% and less than 100 mol%. Particularly preferred is 55 to 99 mol%, more preferred is 60 to 98 mol%, and particularly preferred is 65 to 97 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) is increased, the crosslinking density tends to be too high and the tackiness tends to be lacking. 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.

For the components (A) to (C) of the present invention, the photoelastic coefficient of the acrylic resin (A) is negative with respect to the photoelastic coefficient measured by the method described later, and the ethylenically unsaturated group is 1 The birefringence is efficiently eliminated by the positive photoelastic coefficient of the cured product of the aromatic compound (B) containing one and the ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups. It is preferable in that it can be performed.

In the present invention, the pressure-sensitive adhesive composition [I] containing the acrylic resin (A), the monofunctional aromatic compound (B), and the polyfunctional unsaturated compound (C) as essential components contains active energy. The present invention provides a pressure-sensitive adhesive that is cured by radiation and / or heat (irradiation with active energy radiation and / or heating). In such curing, the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C) are polymerized (polymerized) by active energy rays and / or heat and cured.
When the acrylic resin (A) is involved in the reaction, it is limited to the polymerization of the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C) by active energy rays and / or heat. In addition, curing accompanying polymerization of the acrylic resin (A), the monofunctional aromatic compound (B), and the polyfunctional unsaturated compound (C) also occurs.

When curing with the active energy ray and / or heat, the pressure-sensitive adhesive composition [I] further contains a polymerization initiator (D), so that the reaction during irradiation with active energy ray and / or heating is performed. Is preferable in that it can be stabilized.

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

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

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

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.

The photopolymerization initiator (d1) is not particularly limited as long as it generates radicals by the action of light, and is an intramolecular self-cleavage type photopolymerization initiator (d1-1) or hydrogen abstraction type photopolymerization. Initiator (d1-2) is used.

Examples of the intramolecular self-cleaving photopolymerization initiator (d1-1) include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl. Propan-1-one, 1- (4-isopropylenephenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 -On, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Propyl ether, benzoin isobutyl ether, benzyldimethyl ketal, α-acyloxime ester, acylphosphine oxide, methylphenylglyoxylate, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 4- Examples thereof include benzoyl-4'-methyldiphenyl sulfide, among which 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone are preferred.

Examples of the hydrogen abstraction type photopolymerization initiator (d1-2) include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 3,3′-dimethyl-4-methoxybenzophenone. 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, camphorquinone, dibenzosuberone 2-ethylanthraquinone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, benzyl, 9,10-phenanthrenequinone, among others, benzophenone, methylbenzophenone, , 4,6- Trimethyl benzophenone are preferred.

In the present invention, it is preferable to use a hydrogen abstraction type photopolymerization initiator (d1-2) from the viewpoint of excellent durability, and in particular, an intramolecular self-cleavage type photopolymerization initiator (d1-1) and hydrogen Use of both of the drawing type photopolymerization initiators (d1-2) is preferable in that the balance between photocrosslinking of the surface portion of the pressure-sensitive adhesive layer and internal photocrosslinking is improved, and the total performance is improved.

Examples of the combination of the self-cleaving photopolymerization initiator and the hydrogen abstraction photopolymerization initiator include self-cleaving 1-hydroxycyclohexyl phenyl ketone or 2-hydroxy-2-methyl-1-phenylpropan-1-one And hydrogen abstraction type benzophenone, methylbenzophenone, or 2,4,6-trimethylbenzophenone are suitable.

In addition, if necessary, as an auxiliary of the photopolymerization initiator, triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 2-dimethylaminoethylbenzoic acid, 4-dimethylaminobenzoic acid Acid ethyl, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxan It is also possible to use Song etc. together. These can be used alone or in combination of two or more.

Examples of the thermal polymerization initiator (d2) include methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl cyclohexanone 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 4-di-t-butylperoxycyclohexyl) propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydro Peroxide, t-butyl hydroperoxide, α, α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane , T-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethyl Hexanoyl peroxide, octanoylpa 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-ethoxyethylperoxydicarbonate, di-2-ethoxyhexylperoxydicarbonate, di-3-methoxybutylperoxydicarbonate, di-s-butylperoxydicarbonate, Di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3- Tramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxy Pivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanooate, 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 peroxyisobutylene , T-butyl peroxymalate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy- 2-ethylhexyl monocarbonate, t-butylperoxyacetate, t-butylperoxy-m-toluylbenzoate, t-butylperoxybenzoate, 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-butyltrimethylsilyl Peroxide, 3,3 ', 4,4'-teto Organic peroxide initiators such as la (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 Dihydride chloride, 2,2'-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydro Chloride, 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 Propane] 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- Methyl-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.

The content of the polymerization initiator (D) is 0.01 to 20 parts by weight, particularly 0.1 to 10 parts by weight, and more preferably 0.3 to 100 parts by weight of the acrylic resin (A). It is preferably ˜5 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. Further, the amount is preferably 0.01 to 100 parts by weight, more preferably 0.1 to 100 parts by weight with respect to 100 parts by weight as the total of the monofunctional aromatic compound (B) and the polyfunctional unsaturated compound (C). 20 parts by weight, particularly preferably 1 to 12 parts by weight.

Further, when an intramolecular self-cleaving photopolymerization initiator (d1-1) and a hydrogen abstraction photopolymerization initiator (d1-2) are used in combination as the photopolymerization initiator (d1), a self-cleaving photopolymerization initiator (d1) is used. The ratio of the photopolymerization initiator (d1-1) to the hydrogen abstraction type photopolymerization initiator (d1-2) is (d1-1) :( d1-2) = 70: 30 to 1:99 (weight ratio) It is preferable that (d1-1) :( d1-2) = 55: 45 to 5:95 (weight ratio), more preferably (d1-1) :( d1-2) = 45: It is 55 to 10:90 (weight ratio), and if the content ratio of (d1-1) is too much or too little, there is a tendency that the cross-linking balance of the entire pressure-sensitive adhesive layer tends to be lost, and the adhesive properties may be inferior. is there.

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. For the high-pressure mercury lamp, for example, 5 ~ 3000mJ / cm ^2, preferably carried out at a 10 ~ 1000mJ / cm ² conditions. In the case of the electrodeless lamp, eg, ² ~ 1500mJ / cm 2, preferably carried out at the 5 ~ 500mJ / cm ² conditions. The irradiation time varies depending on the type of light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but it may be usually from several seconds to several tens of seconds, and in some cases, 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.

Further, when the thermal polymerization initiator (d2) is used as the polymerization initiator (D), the polymerization reaction is started by heating and allowed to proceed. 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 It is preferably 70 ° C. to 170 ° C., and the treatment time is usually preferably 0.2 to 20 minutes, particularly preferably 0.5 to 10 minutes.

Examples of the crosslinking agent (E) include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a melamine crosslinking agent, an aldehyde crosslinking agent, an amine crosslinking agent, and a metal chelate crosslinking agent. 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, 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-based 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. Examples include '-bis (1-aziridinecarboxamide), N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide), and the like.

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, and polyamide.

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.

These cross-linking agents (E) may be used alone or in combination of two or more.

The content of the crosslinking agent (E) is usually preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, with respect to 100 parts by weight of the acrylic resin (A). Particularly preferred is 0.1 to 2 parts by weight. When the amount of the crosslinking agent (E) is too small, there is a tendency that the cohesive force is insufficient and sufficient durability cannot be obtained. When the amount is too large, the flexibility and the adhesive strength are lowered, the durability is lowered, and peeling is caused. Since it tends to occur, the use as an optical member tends to be difficult.

In the present invention, it is preferable to further contain a silane coupling agent (F) as a constituent component of the pressure-sensitive adhesive composition [I] in terms 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 include silane coupling agents, amino group-containing silane coupling agents, amide group-containing silane coupling agents, isocyanate group-containing silane coupling agents, and the like. 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, for example, 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, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

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

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

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

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

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

Here, about the adhesive sheet which has an adhesive obtained by hardening the adhesive composition of this invention, the adhesive (layer) contains acrylic resin (A) and one ethylenically unsaturated group. The polymer of the aromatic compound (B), the aromatic compound (B) containing one ethylenically unsaturated group, and a pressure-sensitive adhesive containing an organic solvent are easy to exert the effect of the present invention. preferable.

In this case, the content of the aromatic compound (B) containing one ethylenically unsaturated group contained in the cured pressure-sensitive adhesive is preferably 0.1 to 10% by weight, particularly preferably 1 to The content of the organic solvent is 0.5 wt ppm to 5 wt%, preferably 1 to 1000 wt ppm, and particularly preferably 10 to 100 wt ppm.

Furthermore, the pressure-sensitive adhesive preferably contains an alkyl acrylate monomer (a1). For example, this is derived from the production of the acrylic resin (A).

When the acrylic acid ester monomer (a1) is contained, it is 1 ppm to 5%, preferably 10 ppm to 1000 ppm, particularly preferably 50 to 100 ppm.

And the optical member with an adhesive layer can be obtained by laminating and forming the adhesive layer which consists of the said adhesive on an optical member (optical laminated body).

In the optical member with the pressure-sensitive adhesive layer, it is preferable to further provide 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 with 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 After performing the process according to at least one of irradiation and 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 the reaction time of the chemical cross-linking of the adhesive. As the aging conditions, the temperature is usually from room temperature to 70 ° C., and the time is usually from 1 day to 30 days. Specifically, for example, the treatment may be performed under conditions such as 23 ° C. for 1 day to 20 days, 23 ° C. for 3 to 10 days, 40 ° C. for 1 day to 7 days, and the like.

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

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

The gel fraction of the pressure-sensitive adhesive layer produced by the above method is preferably 30 to 99%, particularly preferably 60 to 90%, more preferably 70, from the viewpoint of durability performance and light leakage prevention performance. ~ 85%. 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 gel percentage is defined as the weight percentage of the insoluble pressure-sensitive adhesive component immersed in the wire mesh for 24 hours. However, the weight of the substrate is subtracted.

Further, the refractive index of the pressure-sensitive adhesive layer produced by the above method is preferably 1.470 to 1.575, particularly preferably 1.475 to 1.550, and further preferably 1.475 to 1.520. Particularly preferred is 1.480 to 1.500. If the refractive index is too low, birefringence compensation of the entire optical laminate tends to be insufficient, and if it is too high, the refractive index difference from the optical film becomes large, and interface reflection tends to occur.

This refractive index is a value measured at 23 ° C. with NaD line using an “Abbe refractometer 1T” manufactured by Atago Co., Ltd.

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 adhering to 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 one obtained by laminating a cellulose triacetate film as a protective film on both sides of a polarizing film. The polarizing film has an average polymerization degree of 1,500 to 10,000, A uniaxially stretched film dyed with an aqueous solution of iodine-potassium iodide or a dichroic dye (usually 2 to 10 times, preferably a film made of a polyvinyl alcohol resin having a degree of conversion of 85 to 100 mol% as a raw film. 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 a polybutyral resin and a polyvinyl formal resin, which are obtained by reacting polyvinyl alcohol with an aldehyde in the presence of an acid can be given.

In the present invention, the acrylic resin (A), the aromatic compound (B) containing one ethylenically unsaturated group, and the ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups ), The photoelastic coefficient of the acrylic resin (A) is negative, and the photoelastic coefficient of the cured product of the aromatic compound (B) and the ethylenically unsaturated compound (C) is positive. An agent composition can also be used.

In the present invention, the sign of the photoelastic coefficient is measured as follows.
<Measurement conditions for positive and negative photoelastic coefficient>
A film-like test piece is set on a photoelasticity measuring apparatus (manufactured by UNIOPT Co., Ltd .: “PEL-3A-102R”), and the sign of the photoelastic coefficient is measured.
The sign of the photoelastic coefficient is positive when the main axis direction is in the 0 ° direction when the stretching direction is 0 ° and the direction perpendicular to the stretching direction is 90 ° in the plane including the width and length. The case where the main axis direction is in the 90 ° direction is defined as negative.

Regarding the thickness of the test piece at the time of the above measurement, the sign of the photoelastic coefficient is due to the difference in refractive index in an arbitrary plane, and the sign of the photoelastic coefficient is not affected by the thickness. It is sufficient to use a thickness that is easy to handle, such as workability, but a thickness of 1 to 1000 μm is usually used.

The size of the test piece at the time of the above measurement is not particularly limited as long as it is within a range that can be set in a test apparatus, but usually a test piece having a length of 20 to 50 mm and a width of 10 to 20 mm is used.

Photoelasticity refers to the phenomenon in which the birefringence changes when the material is stressed and the molecules that make up the material are oriented. In the case of uniaxial stretching, the stress direction matches the stretching direction. Therefore, the sign of the photoelastic coefficient can be determined by measuring the principal axis direction of birefringence that appears when the test piece is stretched. Therefore, as for the draw ratio of the test piece at the time of the measurement, it is only necessary to set a magnification at which the main axis orientation is stable, and a soft material such as an adhesive is likely to undergo orientation relaxation and stress relaxation, and the main axis orientation is low when the draw ratio is small. Since it may not be possible to measure stably, it may be stretched about 2 to 5 times the original test piece length, and if it is hard like a film, it may be stretched about 1.01 to 2 times the original test piece length.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, “parts” and “%” mean weight basis unless otherwise specified.

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

Moreover, the positive / negative measurement of the photoelastic coefficient of acrylic resin (A) was performed as follows.
<Measurement of photoelastic coefficient positive / negative 1>
The acrylic resin (A) was applied to SP-01 (lightly peeled PET), dried at 100 ° C. for 3 minutes, and then SP-003 (heavyly peeled PET) was laminated. The obtained sheet was aged at 40 ° C. for 1 week to obtain an adhesive sheet having an adhesive layer thickness of 25 μm. After this adhesive sheet was cut into 3 cm × 2 cm, only the adhesive layer was set in a photoelasticity measuring apparatus (manufactured by UNIOPT Co., Ltd .: “PEL-3A-102R”). Both ends of the pressure-sensitive adhesive layer were pulled and the principal axis orientation when stretched twice was measured to determine whether the photoelastic coefficient was positive or negative.
The main axis (slow axis) orientation in the 0 ° direction was positive, and the main axis (slow axis) orientation in the 90 ° direction was negative.

[Preparation of Acrylic Resin (A)] (See Table 1)
[Acrylic resin (A-1)]
A four-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer was charged with 98.5 parts of butyl acrylate (a1), 1 part of 2-hydroxyethyl acrylate (a2), acrylic acid ( a2) 0.5 part, 75 parts of ethyl acetate and 45 parts of acetone were added, and after heating to reflux, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and the mixture was refluxed at ethyl acetate for 3 hours. After the reaction, the reaction mixture was diluted with ethyl acetate, and the acrylic resin (A-1) solution (weight average molecular weight (Mw) 2 million, dispersity (Mw / Mn) 3.1, glass transition temperature -54 ° C., solid content 16 %, Viscosity 8,000 mPa · s (25 ° C.)).

[Acrylic resin (A-2)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 97 parts of butyl acrylate (a1), 3 parts of acrylic acid (a2) and 100 parts of ethyl acetate, 45 parts of acetone After starting the reflux with heating, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, reacted at the reflux temperature of ethyl acetate for 3 hours, diluted with ethyl acetate, and then the acrylic resin (A -2) A solution (weight average molecular weight (Mw) 1.8 million, dispersity (Mw / Mn) 3.2, glass transition temperature -53 ° C., solid content 18%, viscosity 8,000 mPa · s (25 ° C.)) was obtained. It was.

[Acrylic resin (A-3)]
In a four-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 98.5 parts of butyl acrylate (a1), 1.5 parts of 2-hydroxyethyl acrylate (a2) and acetic acid Charge 120 parts of ethyl and 45 parts of acetone, start heating and reflux, add 0.03 part of azobisisobutyronitrile (AIBN) as a polymerization initiator, react for 3 hours at reflux temperature of ethyl acetate, and dilute with ethyl acetate Acrylic resin (A-3) 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 (A-4)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 95 parts of butyl acrylate (a1), 5 parts of acrylic acid (a2), 120 parts of ethyl acetate, acetone 45 After starting to reflux with heating, 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 ( A-4) A solution (weight average molecular weight (Mw) 1.5 million, dispersity (Mw / Mn) 3.4, glass transition temperature -51 ° C., solid content 23%, viscosity 8000 mPa · s (25 ° C.)) was obtained. .

[Acrylic resin (A-5)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 95 parts of butyl acrylate (a1), 5 parts of acrylic acid (a2) and 100 parts of ethyl acetate, 45 parts of acetone After starting the reflux with heating, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, reacted at the reflux temperature of ethyl acetate for 3 hours, diluted with ethyl acetate, and then the acrylic resin (A -5) A solution (weight average molecular weight (Mw) 1.7 million, dispersity (Mw / Mn) 3.2, glass transition temperature -51 ° C., solid content 18%, viscosity 8,000 mPa · s (25 ° C.)) is obtained. It was.

[Acrylic resin (A-6)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 61.3 parts of butyl acrylate (a1), 35 parts of benzyl acrylate, 2-hydroxyethyl acrylate (a2) 3 0.5, 0.2 part (a2) of acrylic acid, 150 parts of ethyl acetate and 45 parts of acetone were added, and after heating to reflux, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and acetic acid was added. After reacting for 3 hours at the reflux temperature of ethyl, it was diluted with ethyl acetate to prepare an acrylic resin (A-6) solution (weight average molecular weight (Mw) 1.5 million, dispersity (Mw / Mn) 3.5, glass transition temperature− 36 ° C., solid content 20%, viscosity 8,000 mPa · s (25 ° C.)).

[Acrylic resin (A-7)]
In a four-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 94.8 parts of butyl acrylate (a1), 0.2 part of 2-hydroxyethyl acrylate (a2), acrylic 5 parts of acid (a2), 120 parts of ethyl acetate and 45 parts of acetone were added, and after heating to reflux, 0.03 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and the mixture was refluxed at ethyl acetate for 3 hours. After the reaction, the mixture was diluted with ethyl acetate, and the acrylic resin (A-7) solution (weight average molecular weight (Mw) 1,500,000, dispersity (Mw / Mn) 3.4, glass transition temperature -51 ° C., solid content 23 %, Viscosity 8000 mPa · s (25 ° C.)).

[Monofunctional 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)
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%)
The following were prepared as the monofunctional aromatic compound (B-3).
O-Biphenyloxyethyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “A-LEN-10T”: molecular weight 268)
The following were prepared as the monofunctional aromatic compound (B-4).
・ Phenylthioethyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., trade name “PhSEA”: molecular weight 207)

[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 the crosslinking agent (E-1).
・ 55% ethyl acetate solution of tolylene diisocyanate adduct of trimethylolpropane (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”)
The following were prepared as the silane compound (F-2).
・ Γ-Mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM803”)
The following were prepared as the silane compound (F-3).
・ Mercapto silane coupling agent (oligomer type) (manufactured by Shin-Etsu Chemical Co., Ltd., “X-41-1805”)

[Examples 1 to 13, Comparative Examples 1 to 6]
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 10,000 mPa · s (25 ° C.)]) to prepare an adhesive composition solution.

The pressure-sensitive adhesive composition solution obtained above was applied to a polyester release sheet so that the thickness after drying was 25 μm, dried at 90 ° C. for 3 minutes, and then formed pressure-sensitive adhesive composition The layer was transferred onto a polyethylene terephthalate (PET) film (thickness: 38 μm), and an ultraviolet light with a peak illuminance of 600 mW / cm ² and an integrated exposure amount of 240 mJ / cm ^{2 using} an electrodeless lamp [H bulb of LH6UV lamp] manufactured by Fusion. Irradiation (120 mJ / cm ² × 2 passes), 23 ° C. × 65% R.D. H. The film was aged for 10 days under the above conditions to obtain a PET film with an adhesive layer.

Using the PET film with the pressure-sensitive adhesive layer thus obtained, the handleability, odor resistance, gel fraction, haze, and refractive index were measured and evaluated according to the following methods. These results are also shown in Table 2 below.

[Handling]
After the obtained PET film with the pressure-sensitive adhesive layer was cut into 25 mm × 40 mm, the release sheet was peeled off, and the pressure-sensitive adhesive layer was touched with a finger, and the tackiness was evaluated according to the following criteria.
○: Good tack feeling ×: Not much tack feeling

[Odor resistance]
The obtained PET film with an adhesive layer was 23 ° C. × 50% R.D. H. And then left for 3 hours under temperature and humidity control conditions, the release sheet was peeled off, the smell was sniffed, and evaluated according to the following criteria.
○: Do not feel monomer odor ×: Feel monomer odor

[Gel fraction]
After the obtained PET film with an adhesive layer is cut into 40 mm × 40 mm, the release sheet is peeled off and the adhesive layer side is bonded to a 50 mm × 100 mm SUS mesh sheet (200 mesh). After wrapping the sample from the center with respect to the longitudinal direction, the gel fraction was measured by the change in weight when immersed in a sealed container containing 250 g of toluene at 23 ° C. for 24 hours.

[Haze]
-Manufacture of sample for haze measurement The said adhesive composition solution was apply | coated to the polyester-type light peeling release sheet so that the thickness after drying might be set to 25 micrometers, and after drying for 3 minutes at 90 degreeC, the adhesive formed The adhesive composition layer side is bonded together with a polyester-based heavy release release sheet, and a peak illuminance of 600 mW / cm ² and an integrated exposure amount of 240 mJ / cm ² with an electrodeless lamp [LH6UV lamp H bulb] manufactured by Fusion Irradiation (120 mJ / cm ² × 2 passes), then 23 ° C. × 50% R.D. H. A base material-less pressure-sensitive adhesive layer was obtained by aging for 10 days under the above conditions. The obtained substrate-less pressure-sensitive adhesive layer was cut out to 3 cm × 4 cm, the light release release sheet was peeled off, and the pressure-sensitive adhesive layer side was pressed against an alkali-free glass plate (Corning Corp., Eagle XG), and further The heavy release release sheet was peeled off to obtain a sample for haze measurement.
-Measurement of haze value The diffuse transmittance and total light transmittance of the sample for haze measurement were measured using HAZE MATER NDH2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). This machine conforms to JIS K7361-1.
The values of the obtained diffuse transmittance and total light transmittance were substituted into the following formula to calculate haze.
Haze value (%) = (diffuse transmittance / total light transmittance) × 100

[Refractive index]
Using the above sample for haze measurement, a value at 23 ° C. was measured with NaD line using an “Abbe refractometer 1T” manufactured by Atago Co., Ltd.

Moreover, in Example 13, when the monofunctional aromatic compound (B) and the ethyl acetate concentration remaining in the adhesive (layer) were measured using the PET film with the adhesive layer, the monofunctionality was measured. The concentration of the aromatic compound (B) was 4% by weight, and the ethyl acetate concentration was 25 ppm by weight.
The measuring method is as follows.

[Method for measuring concentration of monofunctional aromatic compound (B)]
After the PET film with the pressure-sensitive adhesive layer is cut into 40 mm × 40 mm, the release sheet is peeled off and the pressure-sensitive adhesive layer side is bonded to a 50 mm × 100 mm SUS mesh sheet (200 mesh), and then the longitudinal direction of the SUS mesh sheet After wrapping the sample from the center and wrapping it in a sealed container containing 250 g of acetone, it was immersed in 23 ° C. for 24 hours, and then 1 μL of the obtained acetone solution was injected with a liquid injection autoinjector (Injector: Agilent Technologies) 7683B Series), Gas Chromatography / Mass Fragment Detector (GC: Agilent Technologies 6890N Network GCsystem, MSD: Agilent Technologies 5973inert) to measure the concentration of monofunctional aromatic compounds (B) in the solution did. The column used was DB-17MS (30 m × 250 μmφ × 0.25 μm) manufactured by Agilent, the carrier gas was He, the flow rate was 1.0 ml / min, and the pressure was 7.0 psi (at 40 ° C.). The split ratio was 30: 1 and the inlet temperature was 220 ° C. The oven temperature conditions were 40 ° C. for 5 minutes, 10 ° C./minute, and after reaching 220 ° C., the oven was left for 10 minutes. Transfer line temperature to MSD 220 ° C, scan mode (mass range: 10-600, SCAN frequency: 2.52 / sec). In addition, the density | concentration of a monofunctional aromatic compound (B) is the density | concentration of the monofunctional aromatic compound (B) in the acetone solution obtained by the said measurement, and the weight of PET film with an adhesive layer of said 40 mm x 40 mm. It was calculated from the weight of a PET film of 40 mm × 40 mm.

[Measurement method of ethyl acetate concentration]
The obtained PET film with an adhesive layer is cut into 25 mm × 25 mm, and the release PET is peeled off and weighed. The sample was placed in a 20 ml vial and sealed. The bottle was heated with a headspace autosampler (Agilent Technologies Headspace Sampler G1888) at 120 ° C. for 30 minutes, and the heated gas was taken out under the conditions of (15 psi × 4 minutes), followed by gas chromatography / mass fragment detector (GC : 6890N Network GCsystem manufactured by Agilent Technologies, MSD: 5973inert manufactured by Agilent Technologies), and the concentration of ethyl acetate contained in the gas was measured. The column used was DB-17MS (30 m × 250 μmφ × 0.25 μm) manufactured by Agilent, the carrier gas was He, the flow rate was 1.0 ml / min, and the pressure was 7.0 psi (at 40 ° C.). The split ratio was 30: 1 and the inlet temperature was 220 ° C. The oven temperature conditions were 40 ° C. for 5 minutes, 10 ° C./minute, and after reaching 220 ° C., the oven was left for 10 minutes. Transfer line temperature to MSD 220 ° C, scan mode (mass range: 10-600, SCAN frequency: 2.52 / sec).
Although only ethyl acetate was measured at this time, it was general and measured on behalf of ethyl acetate typically used in this example.

<Measurement of positive and negative photoelastic coefficient 2>
Further, the positive / negative of the photoelastic coefficient of the monofunctional aromatic compounds (B-1 to B-4) was measured. A monofunctional aromatic compound alone is difficult to handle because the cured product is not crosslinked, and a small amount of polyfunctional unsaturated compound is blended, and the photoelastic coefficient of the cured product is determined to be positive or negative. The photoelastic coefficient was determined as positive or negative. . That is, 100 parts of a monofunctional aromatic compound (B-1 to B-4), 10 parts of a polyfunctional unsaturated compound (C-1), and 10 parts of a photopolymerization initiator (D-1) are blended. , Coated on a glass plate provided with a spacer having a thickness of 400 μm, laminated on the glass plate from above, and a peak illuminance: 600 mW / cm ² with an electrodeless lamp manufactured by Fusion [H bulb of LH6UV lamp], integrated exposure amount: It was cured by irradiation with ultraviolet rays at 240 mJ / cm ² (120 mJ / cm ² × 2 passes). The thickness of the obtained cured product was about 300 μm. This cured product was cut into 3 cm × 2 cm, and set in a photoelasticity measuring apparatus (manufactured by UNIOPT Co., Ltd .: “PEL-3A-102R”) (the end of the long axis was sandwiched with a chuck). Both ends of the cured product were pulled and the principal axis orientation when deformed by 2% was measured, and the positive / negative of the photoelastic coefficient was determined in the same manner as described above.
As a result, the photoelastic coefficients of the cured products of the monofunctional aromatic compounds (B-1 to B-4) were all positive.

Next, the pressure-sensitive adhesive composition solutions of Examples 1 to 13 and Comparative Examples 1 to 6 were applied to a polyester release sheet so that the thickness after drying was 25 μm, and dried at 90 ° C. for 3 minutes. The formed pressure-sensitive adhesive composition layer was transferred onto a polarizing plate (thickness: 190 μm), and peak illuminance: 600 mW / cm ² , integrated exposure amount: 240 mJ / with an electrodeless lamp [LH6UV lamp H bulb] manufactured by Fusion. Irradiation with ultraviolet rays was performed at cm ² (120 mJ / cm ² × 2 passes), and 23 ° C. × 65% R.D. H. The film was aged for 10 days under the above conditions to obtain a polarizing plate with an adhesive layer.
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 adhesive strength 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, autoclave treatment (50 ° C, 0.5 MPa, 20 minutes) was performed, and then foaming and peeling were evaluated in the following durability tests (1) to (4) (moisture and heat resistance test, heat cycle test and heat resistance test). I did it. 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.

〔An endurance 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 an operation of leaving at 35 ° C for 60 minutes and then 70 ° C for 60 minutes (3) Heat 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 of less than 0.5 mm or occurrence of floating marks less than 0.5 mm Δ ・・・ Peeling of 0.5 mm or more and less than 10 mm, or generation of lift marks of 0.5 mm or more and less than 10 mm × ・・・10 mm or more peeling or 10 mm or more of lift mark (light leakage)
◎ ・・・ There is almost no light leakage ○ ・・・ Slight leakage occurs △ ・・・ Slight leakage occurs × ・・・ Large light leakage occurs on 4 sides

〔Adhesive force〕
About the prepared polarizing plate with an adhesive layer, it cuts to width 25mm width, peels off a release film, presses the adhesive layer side to a non-alkali glass board (Corning company make, "Corning 1737"), and polarized light The plate and the glass plate were bonded together. Thereafter, autoclaving (50 ° C., 0.5 MPa, 20 minutes) was performed, and 23 ° C. 50% R.D. H. A 180 ° C. peel test was performed after leaving the sample for 24 hours. In the peelability, it is desired that the adhesive strength is small, and the target is 10 N / 25 mm or less after one day.

The pressure-sensitive adhesives of the examples are excellent in balance at a very high level of durability, light leakage resistance, and adhesive strength when a polarizing plate and a glass plate are pasted. The comparative examples 1 to 6 did not satisfy the required performance in the following points, whereas they were excellent in haze and odor resistance.

In Comparative Example 1 in which the monofunctional aromatic compound (B-1) was not blended, although the physical properties of the pressure-sensitive adhesive layer itself were excellent, the performance at the time of attaching the polarizing plate and the glass plate was inferior, In Comparative Example 2 in which the blending amount of the polyfunctional unsaturated compound (C-1) was increased without blending the monofunctional aromatic compound (B-1), the performance when the polarizing plate and the glass plate were attached However, the physical properties of the pressure-sensitive adhesive layer itself were inferior.
A polarizing plate and a glass plate were also used in Comparative Example 3 in which the monofunctional aromatic compound (B-1) was blended only in 15.7 mol% with respect to the total amount of (B-1) and (C-1). Although the performance at the time of pasting was excellent, the physical properties of the pressure-sensitive adhesive layer itself were inferior (inferior in handleability).
In Comparative Example 4 using an acrylic resin copolymerized with an aromatic monomer, an unpleasant monomer odor dependent on the aromatic monomer that was not copolymerized was generated, and a slight foaming occurred in the heat resistance test due to the influence of the residual monomer. The result was generated.
In Comparative Examples 5 and 6 in which fluorene, which is a non-curable aromatic ring-containing low molecular compound, is mixed, in addition to the generation of fluorene-derived odor, the compatibility with acrylic resins is poor when the amount of mixing is increased Therefore, the haze of the coating film was extremely deteriorated, and furthermore, the low molecular weight compound bleeded out and did not function as an adhesive layer at all.

In addition, in the said Example, although it showed about the specific form in this invention, the said Example is only a mere illustration and is not interpreted limitedly. Further, all modifications belonging to the equivalent scope of the claims are within the scope of the present invention.

In the pressure-sensitive adhesive of the present invention, the pressure-sensitive adhesive layer after curing with active energy rays and / or heat is excellent in handleability (tack) and optical properties (haze), and even under high temperature and high humidity environments, A liquid crystal display device that has excellent adhesion between an optical laminate, particularly an optical member such as a polarizing plate, and a glass substrate, does not cause foaming or peeling between the pressure-sensitive adhesive layer and the glass substrate, and does not cause color unevenness or light leakage. Obtainable. Therefore, it is particularly effective as a pressure-sensitive adhesive for optical members, and is very useful as a pressure-sensitive adhesive for obtaining an optical member with a pressure-sensitive adhesive layer and an image display device obtained by using them.

Claims

Adhesive composition containing acrylic resin (A), aromatic compound (B) containing one ethylenically unsaturated group, and ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups The product [I] is an adhesive that is cured by active energy rays and / or heat, and the content of the aromatic compound (B) is 3 to 300 parts by weight with respect to 100 parts by weight of the acrylic resin (A). And the content ratio (mol%) of the aromatic compound (B) to the total amount of the aromatic compound (B) and the ethylenically unsaturated compound (C) is larger than 50 mol%. .
The acrylic resin (A) contains 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. Adhesive.
The pressure-sensitive adhesive according to claim 1 or 2, wherein the aromatic compound (B) contains two or more aromatic rings, sulfur atoms, or bromine atoms.
4. The pressure-sensitive adhesive according to claim 1, wherein the pressure-sensitive adhesive composition [I] contains a polymerization initiator (D).
The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive composition [I] contains a crosslinking agent (E) and is crosslinked with a crosslinking agent.
An adhesive for optical members, comprising the adhesive according to any one of claims 1 to 5.
The optical member pressure-sensitive adhesive according to claim 6, wherein the optical member is a polarizing plate.
An optical member with a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive for optical members according to claim 6 or 7, and a laminated structure of the optical members.
An image display device using the optical member with an adhesive layer according to claim 8.
An acrylic resin (A), an aromatic compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups, and aromatic The content of the compound (B) is 3 to 300 parts by weight with respect to 100 parts by weight of the acrylic resin (A), and the fragrance with respect to the total amount of the aromatic compound (B) and the ethylenically unsaturated compound (C) An active energy ray and / or a thermosetting pressure-sensitive adhesive composition, wherein the content (mol%) of the group compound (B) is greater than 50 mol%.
Contains acrylic resin (A), polymer of aromatic compound (B) containing one ethylenically unsaturated group, aromatic compound (B) containing one ethylenically unsaturated group, and organic solvent A pressure-sensitive adhesive.
An acrylic resin (A), an aromatic compound (B) containing one ethylenically unsaturated group, and an ethylenically unsaturated compound (C) containing two or more ethylenically unsaturated groups A pressure-sensitive adhesive characterized in that the photoelastic coefficient of the acrylic resin (A) is negative and the photoelastic coefficient of the cured product of the aromatic compound (B) and the ethylenically unsaturated compound (C) is positive. Composition.