KR20130141524A - Adhesive composition for optical components, adhesive for optical components, optical component with adhesive layer, and image display device - Google Patents

Abstract

 Provided is an adhesive composition for an optical member that can achieve both re-peelability and durability, and can suppress color unevenness and light leakage when applied to an image display device such as a liquid crystal display device. This invention is an adhesive composition for optical members which consists of acrylic resin (A) obtained by copolymerizing copolymerization component [I] which has a (meth) acrylic-acid alkylester type monomer (a1) as a main component, N as copolymerization component [I] It relates to a pressure-sensitive adhesive composition for an optical member, comprising-(alkoxyalkyl) (meth) acrylamide monomer (a2).

Description

Adhesive composition for optical members, adhesive for optical members, optical members with an adhesive and an image display device {Adhesive composition for optical components, adhesive for optical components, optical component with adhesive layer, and image display device}

This invention relates to the adhesive composition for optical members, the adhesive for optical members, the optical member with an adhesive layer, and an image display apparatus. Specifically, optical members such as optical films (polarizing film, phase difference film, optical compensation film, brightness enhancement film), which are suitably used for image display devices such as liquid crystal display devices, organic EL display devices, and PDPs, and specifically, The adhesive composition for optical members used for adhesion | attachment of the optical laminated body with which a polarizing film was coat | covered with protective films, such as a cellulose acetate film, and a glass substrate of a liquid crystal cell, the adhesive for optical members which this adhesive composition bridge | crosslinked, The optical member with an adhesive layer in which the adhesive layer containing this adhesive for optical members was formed, especially the polarizing plate with an adhesive layer, and this image display apparatus containing this optical member with an adhesive layer is provided.

Conventionally, the polarizing plate in which both surfaces of polarizers, such as a polyvinyl alcohol-type film to which polarization was given, was covered with protective films, such as a cellulose film, is laminated | stacked on the surface of the liquid crystal cell which has the liquid crystal component orientated between two glass plates. In order to form a liquid crystal display panel, it is common to laminate | stack on the liquid crystal cell surface by contacting and pressing down the adhesive layer provided in the polarizing plate surface to the said liquid crystal cell.

In the adhesive which forms this adhesive layer, when peeling optical members, such as a polarizing plate, from a liquid crystal cell by the miss at the time of processing or the bite of a foreign material, the rework property which can be peeled easily without adhesive residue (material) Reworkability is required. Moreover, when exposed to severe environment, such as high temperature and high humidity for a long time, peeling and foaming resulting from an adhesive arise, and durability is also calculated | required by the adhesive which forms such an adhesive layer. In addition, when a dimensional change occurs over time of the polarizing plate, the pressure-sensitive adhesive layer is distorted to follow the dimensional change of the polarizing plate, and the polymer in the pressure-sensitive adhesive layer partially aligns, thereby causing birefringence, leading to the periphery of the liquid crystal display panel. Color unevenness or light leakage may occur such that the part is brighter or darker than the center. Therefore, it is also required for the adhesive which forms such an adhesive layer to be able to suppress the color unevenness and light leakage which generate | occur | produce by the stress accompanying the dimensional change of optical members, such as a polarizing plate.

For the purpose of solving the above problems, Patent Document 1 discloses an optical film containing a (meth) acrylic polymer copolymerized with a tertiary amino group-containing monomer (see acrylate or acrylamide described in the same document paragraph [0036]). The pressure-sensitive adhesive composition for use is disclosed, and Patent Document 2 discloses a pressure-sensitive polarizing plate in which an acrylic pressure-sensitive adhesive layer containing a specific silane coupling agent is laminated.

JP2009-215528 A JPH9-288214 A

However, in the conventional techniques such as Patent Documents 1 and 2, it is difficult to attain both rework and durability when exposed to high temperature and high humidity for a long time, and when the reworkability is improved, the durability is deteriorated and, conversely, the durability is improved. There was a problem that the reworkability deteriorated, and there was room for new improvement.

This invention is made | formed in view of the said situation, The objective can achieve both rework property and durability, and can suppress a color unevenness and light leakage phenomenon when applied to image display apparatuses, such as a liquid crystal display panel. It provides the adhesive composition for optical members which exist, the adhesive for optical members which this adhesive composition bridge | crosslinked, the optical member with an adhesive layer in which the adhesive layer containing the adhesive for this optical member was formed, and the image display apparatus containing this optical member with adhesive layer is provided. It is in doing it.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in consideration of said situation, this inventor is an N- (alkoxyalkyl) (meth) acrylamide type monomer, ie, a (meth) acrylamide type monomer, and the alkyl chain couple | bonded with the nitrogen of an amide bond By using acrylic resin which uses the monomer substituted by the alkoxy group as a copolymerization component, the reworkability and durability can be achieved, and when it is applied to an image display apparatus, the color unevenness and light leakage phenomenon can be suppressed. Thus, the present invention has been completed.

That is, the summary of this invention is an adhesive composition for optical members which consists of acrylic resin (A) obtained by copolymerizing copolymerization component [I] which has a (meth) acrylic-acid alkylester type monomer (a1) as a main component, and a copolymerization component [I] relates to a pressure-sensitive adhesive composition for an optical member comprising N- (alkoxyalkyl) (meth) acrylamide monomer (a2).

Moreover, it is related with the optical member adhesive which the said adhesive composition for optical members bridge | crosslinked, the optical member with an adhesive layer in which the adhesive layer containing this adhesive for optical members was formed, and the image display apparatus containing this optical member with adhesive layer.

The present invention includes the following aspects.

[1] A pressure-sensitive adhesive composition for an optical member comprising an acrylic resin (A) obtained by copolymerizing a copolymerization component [I] having a (meth) acrylic acid alkyl ester monomer (a1) as a main component and N as a copolymerization component [I]. -(Alkoxyalkyl) (meth) acrylamide type monomer (a2) containing, The adhesive composition for optical members characterized by the above-mentioned.

[2] The pressure-sensitive adhesive composition for optical member according to [1], wherein the copolymer component [I] contains at least one selected from an aromatic ring-containing monomer (a3) and a carboxyl group-containing monomer (a4).

[3] The pressure-sensitive adhesive composition for an optical member according to [1] or [2], which comprises a crosslinking agent (B).

[4] The pressure-sensitive adhesive composition for an optical member according to any one of [1] to [3], comprising a silane coupling agent (C).

[5] The pressure-sensitive adhesive for optical member, wherein the pressure-sensitive adhesive composition for optical member according to any one of [1] to [4] is crosslinked.

[6] The adhesive for an optical member according to [5], wherein the optical member is a polarizing plate.

[7] An optical member with a pressure-sensitive adhesive layer, comprising a laminated structure of a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive for optical members according to [5] or [6] and an optical member.

[8] An image display device comprising the optical member with a pressure sensitive adhesive layer according to [7].

[9] The optical member with a pressure sensitive adhesive layer according to [7], wherein the optical member is a polarizing plate.

Since the adhesive for optical members obtained by bridge | crosslinking the adhesive composition for optical members of this invention is excellent in rework property, when peeling optical members, such as a polarizing plate, in a liquid crystal cell etc. by the miss at the time of processing, and the foreign material bite, adhesive bond remains. It can be easily peeled off without water. Moreover, since the adhesive of this invention is excellent in durability when exposed to high temperature and high humidity for a long time, even if it repeats the change of the environment of high temperature, high humidity, and low temperature-high temperature, an optical laminated body, especially a polarizing plate and a glass substrate The image display apparatus which is excellent in adhesiveness and is hard to produce foaming and peeling between an adhesive layer and a glass substrate can be obtained. Moreover, since the birefringence of an adhesive layer can make near-zero the birefringence of an adhesive layer, even when the dimensional change by time progress of an optical member arises, the optical member with an adhesive layer in which the adhesive layer containing the adhesive of this invention was attached is with this adhesive layer In the image display apparatus containing the optical member, color spots and light leakage can be suppressed.

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated in detail, these show an example of preferable embodiment. In the present invention, (meth) acryl refers to acrylic or methacryl, (meth) acryloyl refers to acryloyl or methacryloyl, and (meth) acrylate refers to acrylate or methacrylate, respectively. .

[Pressure sensitive adhesive composition for optical member]

First, the adhesive composition for optical members of the present invention (hereinafter also referred to simply as "adhesive composition") will be described.

The adhesive composition of this invention contains acrylic resin (A).

Acrylic resin (A) used by this invention contains a (meth) acrylic-acid alkylester monomer (a1) as a main component again N- (alkoxyalkyl) (meth) acrylamide monomer (a2) as an essential component, Preferably, it is made by copolymerizing copolymerization component [I] containing an aromatic ring containing monomer (a3) and / or a carboxyl group-containing monomer (a4).

As such a (meth) acrylic-acid alkylester type monomer (a1), it is preferable that carbon number of an alkyl group is 1-20 normally, especially 1-12, Furthermore, 1-8, especially 4-8, 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, isobonyl (meth) acrylate, and the like. These can be used individually by 1 type or in combination of 2 or more types.

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

"Make the (meth) acrylic-acid alkylester monomer (a1) a main component" means that the (meth) acrylic-acid alkylester monomer (a1) is contained by 50 weight% or more with respect to the whole copolymerization component [I]. The content ratio of such a (meth) acrylic acid alkyl ester monomer (a1) to the entire copolymerization component [I] is preferably 50 to 97% by weight, particularly preferably 60 to 95% by weight, more preferably 80 It is -93 weight%.

When the content rate of such a (meth) acrylic-acid alkylester type monomer (a1) is too small, there exists a tendency for adhesive force to run short when it crosslinks an adhesive composition and uses it as an adhesive.

As N- (alkoxyalkyl) (meth) acrylamide type monomer (a2), carbon number of an alkoxy group is 1-10 normally, especially 1-8, Furthermore, 1-6, especially 1-4, and carbon number of an alkyl group It is preferable that it is 1-6 normally, especially 1-4, Furthermore, 1-2, especially 1, Specifically, For example, N- (methoxymethyl) (meth) acrylamide, N- ( n-butoxymethyl) (meth) acrylamide, N- (iso-butoxymethyl) (meth) acrylamide, N- (n-butoxyethyl) (meth) acrylamide, etc. are mentioned among these, N It is preferable to use-(n-butoxymethyl) acrylamide, N- (methoxymethyl) acrylamide, and N- (iso-butoxymethyl) acrylamide from the viewpoint of excellent balance in durability and reworkability. These can be used individually by 1 type or in combination of 2 or more types.

The content ratio of such N- (alkoxyalkyl) (meth) acrylamide monomer (a2) with respect to the entire copolymerization component [I] is preferably 0.1 to 3% by weight, particularly preferably 0.3 to 2% by weight, More preferably, it is 0.3-1 weight%. If the content ratio of such N- (alkoxyalkyl) (meth) acrylamide monomer (a2) is too small, the cohesion force may be insufficient, and the durability and reworkability tend to decrease, and if too large, the viscosity increases or the resin The stability tends to be lowered.

As an aromatic ring containing monomer (a3), for example, phenyl (meth) acrylate, benzyl methacrylate, phenoxyethyl (meth) acrylate, ethoxylated o-phenylphenyl (meth) acrylate, and phenyldiethylene Glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, styrene, α-methylstyrene, and the like. Among these, phenyldiethylene glycol acrylate and phenoxyethyl acrylate. It is preferable to use a in that light resistance is excellent. These can be used individually by 1 type or in combination of 2 or more types.

The content ratio of the aromatic ring-containing monomer (a3) to the entire copolymerization component [I] is preferably 3 to 20% by weight, particularly preferably 3 to 15% by weight, more preferably 5 to 15% by weight.

If the content ratio of the aromatic ring-containing monomer (a3) is too small, light leakage resistance (performance of suppressing light leakage) tends to be lowered. If too much, light leakage resistance is lowered or the adhesion performance of acrylic resin is inferior. It tends to lose or the stability of the polymerization decreases.

Examples of the carboxyl group-containing monomer (a4) include (meth) acrylic acid, acrylic acid dimers, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide-N-glycolic acid, and cinnamic acid. These etc. are mentioned, Especially, (meth) acrylic acid is used preferably. These can be used individually by 1 type or in combination of 2 or more types.

The content ratio of the carboxyl group-containing monomer (a4) to the entire copolymerization component [I] is preferably 1.5% by weight or less, particularly preferably 0.05 to 1% by weight, more preferably 0.05 to 0.6% by weight. When the content ratio of the carboxyl group-containing monomer (a4) is too small, the cohesion force is insufficient, and the durability performance tends to decrease, and when too large, the viscosity increases or the stability of the resin tends to be poor.

In addition to the monomer of said (a1)-(a4), acrylic resin (A) used by this invention may make another copolymerizable monomer (a5) a copolymerization component [I]. Examples of such other copolymerizable monomers (a5) include hydroxyl group-containing monomers, amino group-containing monomers, acetacetyl group-containing monomers, isocyanate group-containing monomers, glycidyl group-containing monomers, and the like. In view of the crosslinking reaction, a hydroxyl group-containing monomer is preferably used.

As a hydroxyl-containing monomer, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth), for example Caprolactone-modified monomers such as acrylate alkyl esters such as acrylate and 8-hydroxyoctyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, diethylene glycol (meth) acrylate, Oxyalkylene-modified monomers such as polyethylene glycol (meth) acrylate, other primary hydroxyl group-containing monomers such as 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid and N-methylol (meth) acrylamide; 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy 3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylic Contains secondary hydroxyl groups such as rates Nomeo; it may be mentioned 2,2-dimethyl-2-hydroxyethyl (meth) monomers containing a tertiary hydroxyl group, such as acrylate.

Among the hydroxyl group-containing monomers, primary hydroxyl group-containing monomers are preferred because of excellent reactivity with the crosslinking agent. Moreover, using 2-hydroxyethyl acrylate and 4-hydroxy butyl acrylate is especially preferable at the point that there are few impurities, such as di (meth) acrylate, and it is easy to manufacture.

Moreover, as a hydroxyl-containing monomer used by this invention, it is also preferable that the content rate of the di (meth) acrylate which is an impurity uses 0.5 weight% or less, More preferably, it is 0.2 weight% or less, Especially preferably, it is 0.1. It is preferable to use 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 4-hydroxy butyl acrylate at the weight% or less.

As an amino-group containing monomer, t-butylaminoethyl (meth) acrylate, ethyl aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, etc. are mentioned, for example. Can be.

As an acetacetyl group containing monomer, 2- (acetoxy) ethyl (meth) acrylate, an arylacetate acetate, etc. are mentioned, for example.

As an isocyanate group containing monomer, 2-acryloyl oxyethyl isocyanate, 2-methacryloyl oxyethyl isocyanate, these alkylene oxide addition products, etc. are mentioned, for example.

As a glycidyl-group containing monomer, (meth) acrylic-acid glycidyl, (meth) acrylic-acid aryl glycidyl, etc. are mentioned, for example.

As another example other than another copolymerizable monomer (a5), 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (Meth) acrylate, 2-butoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxy triethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxide Sidipropylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, octosi polyethylene glycol-polypropylene glycol-mono (meth) acrylate, lauxy polyethylene glycol mono (meth) acrylate, stearoxy polyethylene glycol Monomers containing alkoxy groups such as mono (meth) acrylate and oxy alkylene groups;

Acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkylvinyl ether, vinyltoluene, vinylpyridine, vinylpyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester , Allyl alcohol, acryl chloride, methyl vinyl ketone, N-acrylamide methyl trimethyl ammonium chloride, allyl trimethyl ammonium chloride, dimethyl allyl vinyl ketone, and the like.

The content rate of the other copolymerizable monomer (a5) with respect to the whole copolymerization component [I] becomes like this. Preferably it is 5 weight% or less, Especially preferably, it is 0.5-3 weight%, More preferably, it is 0.4-1.6 weight%.

When there are too many content rates of a copolymerizable monomer (a5), there exists a tendency for the effect of this invention to become difficult to obtain.

In the present invention, an amide monomer other than the N- (alkoxyalkyl) (meth) acrylamide monomer (a2) as the other copolymerizable monomer (a5) (that is, an amide monomer having no alkoxy alkyl group, for example, (Meth) acryloyl morpholine, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylamino (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, etc.) do not impair the effects of the present invention. You may use together as a copolymerization component [I] in the range which does not.

In addition, when using an amide type monomer other than N- (alkoxyalkyl) (meth) acrylamide type monomer (a2) as said copolymerizable monomer (a5), the content is normally with respect to the whole copolymerization component [I]. 0.1-2 weight%, Preferably it is 0.3-1 weight% or less, or 0-100 weight% with respect to N- (alkoxyalkyl) (meth) acrylamide type monomer (a2), Preferably it is 0- 50% by weight, particularly preferably 0 to 20% by weight.

Moreover, the content rate of the sum total of N- (alkoxyalkyl) (meth) acrylamide type monomer (a2) and a carboxyl group-containing monomer (a4) is 4 weight% or less with respect to the whole copolymerization component [I], Especially preferably, Preferably it is 0.3-2 weight%, More preferably, it is 0.4-1.6 weight%.

When there are too many content rates of the sum total of such (a2) and (a4), there exists a tendency for a viscosity to become high too much or the stability of resin falls.

In order to achieve high molecular weight of the acrylic resin (A) used in the present invention, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene You may use together the compound which has two or more ethylenically unsaturated groups, such as glycol di (meth) acrylate, a propylene glycol di (meth) acrylate, and divinylbenzene.

In this invention, the copolymerization component [I] containing at least the monomer of said (a1) and (a2), Preferably further containing the monomer of (a3), (a4) and the monomer of (a5) as needed. Although copolymerizing acrylic resin (A) by copolymerization, such copolymerization can be performed by conventionally well-known methods, such as solution radical polymerization, suspension polymerization, block polymerization, emulsion polymerization. For example, (meth) acrylic-acid alkylester monomer (a1), N- (alkoxyalkyl) (meth) acrylamide monomer (a2), aromatic ring containing monomer (a3), and carboxyl group-containing monomer (a4) in an organic solvent. ) And other polymerizable monomers such as copolymerizable monomers (a5) and a polymerization initiator are mixed or added dropwise, and polymerized at reflux or at 50 to 90 ° C. for 2 to 20 hours.

As an organic solvent used for such superposition | polymerization, aromatic hydrocarbons, such as toluene and xylene; esters, such as ethyl acetate and butyl acetate; aliphatic alcohols, such as n-propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone, Ketones, such as methyl isobutyl ketone and cyclohexanone, etc. are mentioned.

As a polymerization initiator used for such radical copolymerization, azo type polymerization initiators, such as azobis isobutyronitrile and azobisdimethylvalonitrile which are normal radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, di-t-butyl Peroxide type polymerization initiators, such as a peroxide and cumene hydroperoxide, etc. are mentioned as a specific example.

The weight average molecular weight (Mw) of the acrylic resin (A) is usually 400,000 to 2 million, preferably 450,000 to 1.9 million, and particularly preferably 500,000 to 1.8 million. If the weight average molecular weight is too small, the durability performance tends to be lowered. If the weight average molecular weight is too large, the diluent solvent is required in large quantities, which is undesirable in view of coatability and manufacturing cost.

Moreover, it is preferable that dispersion degree (weight average molecular weight (Mw) / number average molecular weight (Mn)) of acrylic resin (A) is 20 or less, Especially 15 or less are preferable, 10 or less are more preferable, 7 or less Even more preferred. If such dispersion degree is too high, the durability of an adhesive layer will fall, and it exists in the tendency for foaming etc. to occur easily. In addition, the minimum of dispersion degree is 2 normally at the limit of manufacture.

Further, the glass transition temperature of the acrylic resin (A) is more preferably -80 to -20 ° C, particularly -75 to -30 ° C, -60 to -40 ° C, and if the glass transition temperature is too high, the tag ) Tends to be insufficient, and if it is too low, it tends to be lowered in heat resistance.

In addition, said weight average molecular weight (Mw) is a weight average molecular weight by conversion of a standard polystyrene molecular weight, and it is high-speed liquid chromatography ("Waters 2695 (body)" and "Waters 2414 (detector)" by the Japan Waters company). Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical number of stages: 10,000 stages / piece, filler material: styrene-divinyl benzene copolymer, filler particles It is measured by using three series of diameter: 10 micrometers), and the same method can also be used for number average molecular weight (Mn). Moreover, dispersion degree can be calculated | required by a weight average molecular weight and a number average molecular weight. The glass transition temperature is calculated by the following equation (1) of Fox.

Tg: glass transition temperature (K) of the copolymer

Tga: glass transition temperature (K) of homopolymer of monomer A Wa: weight fraction of monomer A

TgB: glass transition temperature (K) of homopolymer of monomer B Wb: weight fraction of monomer B

Tgn: glass transition temperature (K) of homopolymer of monomer N Wn: weight fraction of monomer N

(Wa + Wb +… + Wn = 1)

In this invention, although the adhesive composition for optical members which contains the said acrylic resin (A) as an essential component is provided by the crosslinking, the adhesive composition for optical members contains a crosslinking agent (B) again, It is preferable that it is an adhesive obtained by being bridge | crosslinked.

As such a crosslinking agent (B), an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a melamine type crosslinking agent, an aldehyde crosslinking agent, an amine crosslinking agent, a metal chelate crosslinking agent is mentioned, for example.

Among these, an isocyanate type crosslinking agent is used suitably from the point of improving adhesiveness with a base material, or the point of reactivity with a base polymer.

As said isocyanate type crosslinking agent, 2, 4- tolylene diisocyanate, 2, 6- tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1, 3- xylene diisocyanate, 1, 4- xylene diisocyanate, hexamethylene di, for example Isocyanate, diphenyl methane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanathmethyl) cyclohexane, tetramethylxylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane tri An adduct of isocyanate and these polyisocyanate compounds and polyol compounds, such as a trimetholpropane, the biuret, the isocyanurate, etc. of these polyisocyanate compounds are mentioned.

As said epoxy-type crosslinking agent, the bisphenol A epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethyleneglycol diglycidyl ether, glycerine diglycidyl ether, glycerine triglycidyl ether, for example. , 1,6-hexanediol diglycidyl ether, trimetholpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl Dimethyl ether etc. are mentioned.

Examples of the aziridine-based crosslinking agent include tetramethylolmethane-tri-β-aziridinylpropionate, trimetholpropane-tri-β-aziridinylpropionate, and N, N'-diphenyl. Methane-4,4'-bis (1-azilidinecarboxyamide), N, N'-hexamethylene-1,6-bis (1-aziridinecarboxyamide), and the like.

As said melamine type crosslinking agent, hexamethoxy methyl melamine, hexaethoxy methyl melamine, hexapropoxy methyl melamine, hexaphthoxy methyl melamine, hexapentyloxy methyl melamine, hexahexyloxy methyl melamine, a melamine resin etc. are mentioned, for example. Can be mentioned.

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

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

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

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

It is preferable that content of the said crosslinking agent (B) is 0.01-10 weight part with respect to 100 weight part of acrylic resin (A), More preferably, it is 0.05-5 weight part, Especially preferably, it is 0.1-2.5 weight part. If the crosslinking agent (B) is too small, the cohesive force is insufficient and tends to be unable to obtain sufficient durability. If too large, the flexibility and the adhesive force are lowered, the durability is lowered, and peeling tends to occur, so that it is difficult to use as an optical member. There is a tendency to lose.

In this invention, it is preferable to contain a silane coupling agent (C) as a structural component of the adhesive composition for optical members from the point that adhesiveness with respect to an optical member improves.

As such a silane coupling agent (C), 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, a carboxyl group containing silane coupling agent, for example And an amino group-containing silane coupling agent, an amide group-containing silane coupling agent and an isocyanate group-containing silane coupling agent. These may be used alone or in combination of two or more thereof. Among these, the epoxy group-containing silane coupling agent and the mercapto group-containing silane coupling agent are preferably used, and the use of the epoxy group-containing silane coupling agent and the mercapto group-containing silane coupling agent in combination also prevents the improvement of the wet heat durability and the adhesive strength from being excessively increased. It is preferable at the point.

As a specific example of the said epoxy group containing silane coupling agent, (gamma)-glycidoxy propyl trimethoxysilane, (gamma)-glycidoxy propyl triethoxysilane, (gamma)-glycidoxy propylmethyl diethoxysilane, (gamma) -glycol, for example Cydoxypropylmethyldimethoxysilane, methyltri (glycidyl) silane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, etc. Although, among them, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4 epoxycyclohexyl ) Ethyltrimethoxysilane.

As a specific example of the said mercapto group containing silane coupling agent, (gamma)-mercaptopropyl trimethoxysilane, (gamma)-mercaptopropyl triethoxysilane, (gamma)-mercaptopropyl dimethoxymethylsilane, etc. are mentioned, for example. .

As content of a silane coupling agent (C), it is 0.001-10 weight part normally with respect to 100 weight part of acrylic resin (A), Preferably it is 0.01-1 weight part, Especially preferably, it is 0.03-0.8 weight part. When there is too little content of such a silane coupling agent (C), there exists a tendency for an addition effect not to be acquired, and too much there exists a tendency for compatibility with acrylic resin (A) to fall, and adhesive force and cohesion force may not be obtained.

In the present invention, an unsaturated group-containing compound (D) and a polymerization initiator (E) are also contained, and the pressure-sensitive adhesive composition for an optical member may be crosslinked by active energy rays and / or heat (active energy ray irradiation and / or heating). have.

When crosslinking by the said active energy ray and / or heat (active energy ray irradiation and / or heating), the adhesive composition for optical members containing an unsaturated group containing compound (D) and a polymerization initiator (E) is used. Thus, by containing an unsaturated group containing compound (D), bridge | crosslinking can be adjusted and it becomes possible to implement | achieve adhesive physical property suitable for an optical member use. Moreover, by containing the said polymerization initiator (E), reaction at the time of active energy ray irradiation and / or heating can be stabilized.

In the case of the said crosslinking, an unsaturated group containing compound (D) is superposed | polymerized (polymerized) by active energy ray and / or heat | fever, and crosslinking (physical crosslinking) with acrylic resin (A) is performed. When acrylic resin (A) is unsaturated group containing acrylic resin, it is not limited to polymerization of the unsaturated group containing compound (D) by active energy ray and / or heat | fever, but contains unsaturated group containing acrylic resin (A) and unsaturated group Crosslinking accompanying polymerization with the compound (D) or the like also occurs.

The unsaturated group-containing compound (D) may be a monofunctional unsaturated group-containing compound having one unsaturated group in one molecule or a polyfunctional unsaturated group-containing compound having two or more unsaturated groups in one molecule, but preferably It is preferable from the point of sclerosis | hardenability at the time of active energy ray irradiation that it is an unsaturated group containing compound which has two or more unsaturated groups, More preferably, it is an unsaturated group containing compound which has three or more unsaturated groups.

As a structure of the said unsaturated group containing compound (D), for example, a urethane (meth) acrylate type compound, an epoxy (meth) acrylate type compound, a polyester (meth) acrylate type compound, or one in 1 molecule Ethylenic unsaturated monomer containing the above ethylenically unsaturated group, for example, a monofunctional monomer, a bifunctional monomer, a trifunctional or more than trifunctional monomer, etc. can be used. Among these, using a urethane (meth) acrylate type compound (d1) and an ethylenically unsaturated monomer (d2) is preferable at the point which is excellent in the hardening rate and stability of reached physical property.

The said urethane (meth) acrylate type compound (d1) is a (meth) acrylate type compound which has a urethane bond in a molecule | numerator, the (meth) acrylic type compound containing a hydroxyl group, and a polyhydric isocyanate compound (polyol type compound as needed) ) What is obtained by making it react by a well-known general method may be used, and as a weight average molecular weight, the thing of 300-4000 can be used normally.

As an ethylenically unsaturated monomer (d2) used by this invention, a well-known general monofunctional monomer, a bifunctional monomer, a trifunctional or more than trifunctional monomer, etc. can be used.

As content of the said unsaturated-group containing compound (D), 0.5-99 weight part is preferable with respect to 100 weight part of acrylic resin (A), More preferably, it is 1-50 weight part, More preferably, it is 8-30 weight part to be. When there is too much content of the said unsaturated-group containing compound (D), compatibility with resin will fall and the coating film will tend to whiten, and when too small, the crosslinking density of an adhesive will become inadequate and light leakage resistance and durability will fall. Tend to be.

As said polymerization initiator (E), although it is possible to use various polymerization initiators, such as a photoinitiator (e1) and a thermal polymerization initiator (e2), for example, especially using a photoinitiator (e1) is extremely short time. It is preferable at the point that it becomes possible to bridge | crosslink (cure) by active energy ray irradiation, such as an ultraviolet-ray.

Moreover, when using the said photoinitiator (e1), when it crosslinks the adhesive composition for optical members by active energy ray irradiation, and when using a thermal polymerization initiator (e2), it crosslinks the adhesive composition for optical members by heating, It is also preferable to use both together as needed.

It does not specifically limit as said photoinitiator (e1) and the said thermal polymerization initiator (e2), A well-known general photoinitiator and a thermal polymerization initiator can be used.

About content of the said polymerization initiator (E), Preferably it is 0.01-10 weight part, Especially preferably, it is 0.1-7 weight part, More preferably, 0.3-3 weight with respect to 100 weight part of said acrylic resin (A). It is wealth. When there is too little content of the said polymerization initiator (E), there exists a tendency for sclerosis | hardenability to become inadequate and a physical property to become unstable, and even if too much, the further effect cannot be acquired.

Moreover, in the adhesive composition for optical members of this invention, other adhesives, such as an antistatic agent and acrylic adhesives other than an acrylic resin (A), a urethane resin, rosin, rosin ester, hydrogen, in the range which does not impair the effect of this invention. Tackifiers such as added rosin esters, phenol resins, aromatic modified terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, styrene resins, xylene resins, and the like, colorants, fillers, anti-aging agents, ultraviolet absorbers, functional dyes, and the like. Known additives and compounds that cause coloration or discoloration by ultraviolet or radiation irradiation can be blended. Moreover, in addition to the said additive, what may contain a small amount of impurities etc. which are contained in the manufacturing raw materials of the component of the adhesive composition for optical members, etc. may be sufficient.

Examples of the antistatic agent include cationic antistatic agents of quaternary ammonium salts such as imidazolium salts and tetraalkylammonium sulfonic acid salts; aliphatic sulfonates, higher alcohol sulfate ester salts and higher alcohol alkylene oxide adduct sulfuric acid esters. Anionic antistatic agents such as salts, higher alcohol phosphate ester salts, higher alcohol alkylene oxide adduct phosphate ester salts; potassium bis (fluorosulfonyl) imide, lithium bis (trifluorosulfonyl) imide, lithium chloride, etc. Alkali metal salts, alkaline earth metal salts, higher alcohol alkylene oxide adducts, polyalkylene glycol fatty acid esters, and the like.

Moreover, in this invention, it is preferable that the adhesive composition for optical members has acrylic resin (A) as a main component, and here, "it has as a main component" uses the said acrylic resin (A) in the adhesive composition whole quantity for optical members. It means that it usually contains 50% by weight or more, preferably 60% by weight or more, and more preferably 70% by weight or more. In addition, the upper limit of content of acrylic resin (A) is 99.9 weight% normally.

In this way, the adhesive composition for optical members used by this invention is obtained, and such an adhesive composition for optical members is bridge | crosslinked, and it becomes the adhesive for optical members of this invention.

[Adhesive for Optical Member]

In the present invention, the gel fraction of the pressure-sensitive adhesive for optical member, in which the pressure-sensitive adhesive composition for optical member is crosslinked, is preferably 60 to 95% in terms of excellent balance between durability and light leakage resistance, and particularly preferably 65 It is -90%, More preferably, it is 70-85%. If the gel fraction is too low, there is a tendency that the lack of durability due to lack of cohesion tends to occur, and if the gel fraction is too high, the cohesion is too high and peeling occurs in the durability test.

In addition, when adjusting the gel fraction of an adhesive in the said range, it is achieved by adjusting the kind and quantity of a crosslinking agent, adjusting the composition ratio of the hydroxyl group and carboxyl group in a composition, etc., for example. Moreover, since the gel fraction changes with each interaction with the ratio of such a crosslinking agent and functional group amount, it is necessary to balance, respectively.

The said gel fraction becomes a reference | standard of a crosslinking degree, and is computed by the following method, for example. That is, an adhesive sheet (without separators) formed by forming a pressure-sensitive adhesive layer on a polymer sheet (for example, polyethylene terephthalate film, etc.) serving as a base material is wrapped with a 200 mesh SUS wire mesh, and then subjected to 23 ° C. in toluene. It is immersed for 24 hours and the weight percentage with respect to the adhesive layer before toluene immersion of the insoluble adhesive component which remained in the wire mesh is made into a gel fraction. However, the weight of the base material is omitted.

The adhesive for optical members of this invention is used for the optical member which contains a display and the optical component which comprises it conceptually. As a display, various displays, such as a word processor, a computer, a mobile telephone, and a television, are mentioned, As an optical component, a polarizing plate, the optical laminated body corresponding to it, etc. are mentioned. The adhesive for optical members of this invention can be variously used besides the optical member with an adhesive layer mentioned later. Since the adhesive for optical members of this invention is especially excellent in rework property and durability, it is useful also as an adhesive of a protective sheet for protecting screens, such as a liquid crystal screen. Moreover, the adhesive for optical members of this invention is temporary surface protection adhesives, such as an electronic board | substrate, adhesive for double-sided tape, adhesive for medical surfaces, adhesive for surface protection, adhesive for general labels, adhesive for seals for toys, adhesive for decorative seals, uneven traceability It can also be used as an adhesive.

[Optical Member with Adhesive Layer]

In this invention, the optical member with an adhesive layer can be obtained by laminating the adhesive layer containing the said adhesive for optical members on one side or both surfaces of an optical member (for example, optical laminated body).

It is preferable to provide a release sheet to the said optical member with an adhesive layer again on the surface (exposure surface) opposite to the surface on the optical member side of an adhesive layer.

Moreover, when using the optical member with an adhesive layer for practical use, the said release sheet is peeled off and used. And as said release sheet, it is preferable to use a silicone type release sheet.

Moreover, when manufacturing the optical member with an adhesive layer, as a method of bridge | crosslinking the adhesive composition for optical members, after apply | coating and drying the adhesive composition for optical members on an optical member, a release sheet is stuck and an aging process is performed. The method of performing and [2] apply | coat and dry the adhesive composition for optical members on a release sheet, and attach a optical member, and the method of performing an aging process is mentioned. Among these, the method [2] is preferable in terms of not damaging the optical member, or in terms of workability and stable production.

The said aging process is performed in order to balance adhesive physical property, As conditions of an aging, temperature is normally from room temperature to 70 degreeC, and time is 1 to 30 days normally, specifically, it is 23 degreeC, for example. What is necessary is just to perform on conditions for 1 to 20 days, 3 to 10 days at 23 degreeC, and 1 to 7 days at 40 degreeC.

At the time of application | coating of the said adhesive composition for optical members, it is preferable to dilute and apply this adhesive composition for optical members to a solvent, As a dilution concentration, Preferably it is 5-60 weight%, Especially preferably, it is 10-30 weight% to be. Moreover, as said solvent, if it melt | dissolves the adhesive composition for optical members, it will not specifically limit, For example, Ester solvents, such as methyl acetate, ethyl acetate, a methyl acetate, ethyl acetate, acetone; methyl ethyl ketone, methyl Ketone solvents such as isobutyl ketone; aromatic solvents such as toluene and xylene; alcohol solvents such as methanol, ethanol and propyl alcohol; Among these, ethyl acetate and methyl ethyl ketone are suitably used in view of solubility, dryness and price.

Moreover, about application | coating of the adhesive composition for optical members, it can carry out by conventional methods, such as roll coating, die coating, gravure coating, comma coating, and screen printing.

Moreover, 5-300 micrometers is preferable normally, as for the thickness of the adhesive layer in the adhesive layer optical member obtained, 10-50 micrometers is especially preferable, 12-30 micrometers is more preferable. If the thickness of the pressure-sensitive adhesive layer is too thin, there is a tendency that the adhesive physical properties are difficult to be stabilized. If the thickness of the pressure-sensitive adhesive layer is too thick, the thickness of the entire optical member tends to be too thick.

As for the optical member with an adhesive layer of this invention, what has a mold release sheet peels a mold release sheet, and attaches an adhesive layer surface to the glass substrate of a liquid crystal cell, for example, and is provided to a liquid crystal display device.

It does not specifically limit as an optical member in the optical member with an adhesive layer of this invention, The optical film used suitably for image display apparatuses, such as a liquid crystal display device, for example, a polarizing plate, a retardation plate, an elliptical polarizing plate, and an optical A compensation film, a brightness improving film, the optical laminated body in which these were laminated | stacked, etc. are mentioned. Especially, it is effective in this invention that it is a polarizing plate.

The polarizing plate used by this invention is what laminated | stacked the cellulose acetate acetate film normally as a protective film on both surfaces of a polarizing film, and as said polarizing film, the average degree of polymerization of 1,500-10,000, saponification degree of 85-100 mol% poly A monoaxially oriented film (usually 2 to 10 times, preferably 3 to 7 times draw ratio) stained with an aqueous solution of iodide-potassium iodide or a dichroic dye is used as a film made of a vinyl alcohol-based resin. Is used.

The polyvinyl alcohol-based resin is usually produced by saponifying polyvinyl acetate polymerized with vinyl acetate, but a small amount of unsaturated carboxylic acid (including salts, esters, amides, nitriles, and the like), olefins, and vinyl ethers You may contain the component copolymerizable with vinyl acetate, such as unsaturated sulfonate. Moreover, what is called polyvinyl acetal resin and polyvinyl alcohol derivatives, such as polybutyral resin and polyvinyl formal resin, etc. which made polyvinyl alcohol react with aldehydes in presence of an acid is also mentioned, for example.

[Image display device]

The optical member with an adhesive layer of this invention can be used suitably for image display apparatuses, such as a liquid crystal display device, an organic electroluminescence display, a PDP, an electronic paper, and an LED panel. The optical member with an adhesive layer of this invention is included. In an image display apparatus, even if it is a high temperature, a high humidity environment, and even if it repeats environmental changes of low temperature-high temperature, foaming and peeling hardly arise between an adhesive layer and an image display apparatus. Moreover, the color stain and light leakage phenomenon which generate | occur | produce by the stress accompanying the dimensional change of optical members, such as a polarizing plate, can be suppressed. Thus, the display quality of the image display device can be maintained.

Example

Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.

In addition, in an example, "part" and "%" mean a basis of weight unless there is particular notice.

First, various acrylic resins (A) were prepared as follows. In addition, the measurement of the weight average molecular weight and number average molecular weight of acrylic resin (A) was measured according to the method mentioned above.

[Preparation of Acrylic Resin (A)]

In Examples 1-13, each monomer (a1)-(a5) and ethyl acetate of the quantity of Table 1 were put into the round bottom flask with four inlets provided with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer. 80 parts and 40 parts of acetone were added, 0.03 parts of azobis isobutyronitrile were added as a polymerization initiator after the start of heating reflux, and the mixture was diluted with ethyl acetate for 3 hours, and then diluted with ethyl acetate to obtain an acrylic resin (A) solution, respectively.

In Example 14, 120 parts of ethyl acetate was put into a four-bottomed flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer, and the temperature was increased while stirring to raise the internal temperature to 75 ° C. 90.4 parts of butyl acrylate (a1) and phenoxy diethylene glycol acrylate (a3) were added after adding whole quantity the solution which melt | dissolved 0.05 parts of isobutyronitrile (polymerization initiator) in 5 parts of ethyl acetate, maintaining internal temperature at 74-76 degreeC. ) 8 parts, a mixed solution of 2-hydroxyethyl acrylate (a5) 1 part, 0.5 parts of N- (n-butoxymethyl) acrylamide (a2), and 0.4 parts of acrylic acid (a4) were added dropwise into the reaction system over 2 hours. It was. Then, after superposing | polymerizing at internal temperature 74-76 degreeC for 5 hours, ethyl acetate was added and the acrylic resin (A) solution was obtained.

In Comparative Examples 1 to 3, a copolymerizable monomer (amide or amine compound) (a5) other than the amount shown in Table 1 was added in place of the N- (alkoxyalkyl) (meth) acrylamide monomer (a2). In Comparative Example 4, the acrylic resin (A) solution was obtained in the same manner as in Examples 1 to 13, except that the monomer (a2) was not added.

Table 1 shows the weight average molecular weight and the number average molecular weight of each acrylic resin (A) solution obtained above.

The monomer represented by the symbol of Table 1 is as follows.

BA: Butyl acrylate

MA: Methyl acrylate

BMAA: N- (n-butoxymethyl) acrylamide

MMAA ： N- (methoxymethyl) acrylamide

IBMAA: N- (iso-butoxymethyl) acrylamide

PEA2: Phenyldiethylene glycol acrylate (Kyoeisha make, brand name "light acrylate P2HA")

PEA ： phenoxyethyl acrylate

AAc: acrylic acid

β-CEA: carboxyethyl acrylate (mixture)

HEA ： 2-hydroxyethyl acrylate

DMAA: Dimethylaminoacrylamide

DMAPAA: Dimethylaminopropylacrylamide

DMAEA: Dimethylaminoethyl acrylate

[Crosslinking agent (B)]

The following were prepared as a crosslinking agent (B).

55% ethyl acetate solution of tolylene diisocyanate adduct of trimetholpropane (manufactured by Nippon Polyurethane Co., Ltd., "Colonate L-55E") (KL-55E)

[Silane coupling agent (C)]

The following were prepared as a silane coupling agent (C).

Γ-glycidoxy propyl trimethoxysilane polyol ("X-41-1805" by Shin-Etsu Chemical Co., Ltd.)

[Antistatic agent]

Potassium bis (fluorylsulfonyl) imide (KFSI) was prepared as an antistatic agent.

[Examples 1-14, Comparative Examples 1-4]

The pressure-sensitive adhesive composition which becomes the pressure-sensitive adhesive forming material for an optical member is prepared by blending the prepared and prepared compounding components in the ratio shown in Table 1 above, and diluting it in methyl ethyl ketone (viscosity [500-1000 mPa · s ( 25 ° C.)]) was prepared an adhesive composition solution.

And after apply | coating the said adhesive composition solution to a polyester type release sheet so that the thickness after drying may be 25 micrometers, and drying at 90 degreeC for 3 minutes, the formed adhesive composition layer side was a polyethylene terephthalate (PET) film (38 micrometers in thickness). It was transferred onto a phase, and then aged under conditions of a temperature of 23 ° C. and a relative humidity of 65% for 10 days to obtain a PET film with an adhesive layer.

The gel fraction and surface resistivity were measured and evaluated in accordance with each method shown below using the PET film with an adhesive layer obtained in this way.

These results are shown in Table 2.

[Measurement method of gel fraction]

After cutting the obtained PET film with an adhesive layer to the size of 40x40 mm, the release sheet was peeled off and the adhesive layer side was stuck to 50x100 mm SUS mesh sheet (200 mesh). After folding a sample by folding it in the center part about the long direction of an SUS mesh sheet, the gel fraction was measured by the weight change at the time of being immersed in the sealed container containing 250 g of toluene.

[Measurement Method of Surface Resistivity]

After cutting the obtained PET film with an adhesive layer into the magnitude | size of 40x40 mm, it was left to stand for 3 hours on condition of the temperature of 23 degreeC x relative humidity 65%, and it heated. The release sheet was peeled off, and the surface resistivity was measured using a resistivity meter (Mitsubishi Chemical Co., Ltd., Hariresuta UP) about the adhesive layer after 10 to 20 seconds. In addition, smaller surface resistivity means higher antistatic performance.

[Preparation of Polarizing Plate with Adhesive Layer]

The adhesive composition solutions of Examples 1-14 and Comparative Examples 1-4 were apply | coated to a polyester mold release sheet so that thickness after drying might be set to 25 micrometers, and it dried at 90 degreeC for 3 minutes, and formed the adhesive composition layer into a polarizing plate ( It was transferred onto a thickness of 190 μm) and then aged under conditions of a temperature of 23 ° C. and a relative humidity of 65% for 10 days to obtain a polarizing plate with an adhesive layer. In addition, the said polarizing plate was cut and used so that it might become 45 degrees with respect to a stretching axis. Using the polarizing plate with a pressure-sensitive adhesive layer thus obtained, the rework resistance, light leakage resistance, and durability (heat resistance test, damp-heat test, heat cycle test) were measured and evaluated according to the respective methods shown below. These results are shown in Table 2.

[Rework property]

About the produced polarizing plate with an adhesive layer, it cut | disconnected to width 25mm width, peeled the release sheet, and pressed the adhesive layer side to the alkali free glass plate (The Corning company make, Eagle XG), and stuck the polarizing plate and glass plate. Thereafter, autoclave treatment (50 ° C., 0.5 MPa, 20 minutes) was performed, and the resultant was allowed to stand for 48 hours in a 50 ° C. environment, followed by 180 ° peeling test after standing in a 23 ° C. environment for 30 minutes. It is preferable that adhesive force is moderately small with respect to rework property, and about 10 N / 25mm is aimed after 48 hours. And evaluated according to the following criteria.

(Evaluation standard)

◎: Less than 10N / 25mm

○: 10N / 25mm or more, less than 15N / 25mm

Δ: 15 N / 25 mm or more but less than 20 N / 25 mm

×: 20N / 25mm or more

[Light leakage resistance]

After leaving the obtained polarizing plate with a pressure-sensitive adhesive layer at 80 ° C. for 1000 hours, a sample for light leakage observation was prepared in which the same sample was attached to both the outside and the inside so that the polarizing plate became cross nicols. The backlight was matched, visually confirmed, and the following criteria evaluated.

(Evaluation standard)

(Double-circle): A perfect omission is not recognized completely.

(Circle): Some light leakage is recognized.

(Triangle | delta): The optical missing of the grade which may interfere with practical use is recognized.

X: Light leakage is severe.

〔durability〕

The release sheet of the obtained polarizing plate with an adhesive layer was peeled off, the pressure-sensitive adhesive layer side was pressed on an alkali-free glass plate (manufactured by Corning Corporation, Eagle XG), and after attaching the polarizing plate and the glass plate, autoclave treatment (50 ° C., 0.5 MPa, 20 minutes) was performed. Then, foaming, peeling, and lifting were evaluated in the durability test (heat resistance test, moisture heat test, and heat cycle test) of following (1)-(3) after that. In addition, the size of the used test piece was 20 cm x 15 cm.

(1) Heat test

90 ℃, 2000 hours endurance test

(2) Moisture resistance test

Endurance test at 60 ° C, relative humidity (R.H.) 90%, 2000 hours

(3) heat cycle test

Endurance test which performs 1000 cycles as one cycle after leaving for 30 minutes at -35 degreeC, and leaving it to stand at 70 degreeC for 30 minutes.

〔Evaluation standard〕

(firing)

◎ ・ ・ ・ No foaming

○ ... almost no foaming

△ ... foaming is seen a little

I can see a lot of foaming

(Peeling)

Less than 0.5 mm peels off or raised marks less than 0.5 mm

△ ··· Peel off of 0.5 mm or more but less than 10 mm or excitation marks of 0.5 mm or more and less than 10 mm

Peeling more than 10 mm or lifting marks more than 10 mm

In the polarizing plates with pressure-sensitive adhesive layers of Examples 1 to 14 containing N- (alkoxyalkyl) (meth) acrylamide monomers (a2), both of reworkability and durability at the time of long exposure to high temperature and high humidity can be achieved. It can be seen that. On the other hand, in Comparative Example 1 using N, N-dialkyl (meth) acrylamide described in Patent Document 2 or the like instead of the N- (alkoxyalkyl) (meth) acrylamide monomer (a2), the reworkability is excellent. It was inferior in durability. Moreover, in the comparative examples 2 and 3 which used the tertiary amino group containing monomer (acrylate, acrylamide) described in patent document 1 etc. instead of the monomer (a2), both reworkability and durability were inferior. In Comparative Example 4 in which the monomer (a2) was not used, the reworkability was excellent, but the durability was insufficient.

Although this invention was detailed also demonstrated with reference to the specific embodiment, it is clear for those skilled in the art that various changes and correction can be added without deviating from the mind and range of this invention.

This application is based on the JP Patent application (Japanese Patent Application No. 2010_229885) of an application on October 12, 2010, The content is taken in here as a reference.

(Industrial availability)

By using the adhesive composition for optical members of this invention, the adhesive for optical members excellent in rework property and durability can be obtained. Moreover, by using the adhesive for optical members of this invention, color unevenness and a light leakage phenomenon can be suppressed in image display apparatuses, such as a liquid crystal display panel.

Claims (8)

It is an adhesive composition for optical members which consists of acrylic resin (A) obtained by copolymerizing copolymerization component [I] which has a (meth) acrylic-acid alkylester type monomer (a1) as a main component, and N- (alkoxy as a copolymerization component [I] An alkyl) (meth) acrylamide type monomer (a2) is contained, The adhesive composition for optical members characterized by the above-mentioned. The method according to claim 1,
At least one selected from an aromatic ring containing monomer (a3) and a carboxyl group-containing monomer (a4) is contained as a copolymerization component [I], The adhesive composition for optical members characterized by the above-mentioned. The method according to claim 1 or 2,
It contains the crosslinking agent (B), The adhesive composition for optical members characterized by the above-mentioned. 4. The method according to any one of claims 1 to 3,
A silane coupling agent (C) is contained, The adhesive composition for optical members characterized by the above-mentioned. The adhesive for optical members of any one of Claims 1-4 was bridge | crosslinked, The adhesive for optical members characterized by the above-mentioned. The method according to claim 5,
The optical member is a polarizing plate, The adhesive for optical members. The optical member with an adhesive layer containing the laminated structure of the adhesive layer and optical member containing the adhesive for optical members of Claim 5 or 6. The optical member with an adhesive layer of Claim 7 is contained, The image display apparatus characterized by the above-mentioned.