JP2015232059A - Adhesive composition for polarizing plate, adhesive for polarizing plate, and polarizing plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a polarizing plate, which is an adhesive excellent in adhesive force and suitable for bonding various protective films for a polarizing plate with a polarizer, particularly, for bonding a protective film other than TAC with a polarizer, and which has excellent production efficiency and excellent resistance to a color void.SOLUTION: The adhesive composition for a polarizing plate comprises a metal or semimetal compound (A) that can form a chelate, a photopolymerizable compound (B) having a functional group that can form a chelate with the metal or semimetal, and a urethane (meth)acrylate compound (C); or the adhesive composition comprises a chelate compound (A-B) formed from a metal or semimetal compound (A) that can form a chelate and a photopolymerizable compound (B) having a functional group that can form a chelate with the metal or semimetal, and a urethane (meth)acrylate compound (C).

Description

  The present invention relates to an adhesive composition for polarizing plates, an adhesive for polarizing plates, and a polarizing plate using the same, and more specifically, a polarizer and a protective film constituting a polarizing plate used in a liquid crystal display device and the like. It is related with the adhesive composition for polarizing plates used for the active energy ray hardening-type acrylic adhesive suitable for bonding of this.

  Liquid crystal display devices are widely used as image display devices for liquid crystal televisions, computer displays, mobile phones, digital cameras, and the like. Such a liquid crystal display device has a configuration in which polarizing plates are laminated on both sides of a glass substrate in which liquid crystal is encapsulated, and various optical functional films such as a retardation plate are laminated thereon as necessary.

  Conventionally, a polarizing plate has been used as a structure in which a protective film is bonded to at least one surface, preferably both surfaces, of a polarizer made of a polyvinyl alcohol film. Here, as a polarizer, a dichroic substance such as iodine is formed in a PVA film formed by using a polyvinyl alcohol resin having a high saponification degree (hereinafter, polyvinyl alcohol is abbreviated as “PVA”). A uniaxially stretched PVA-based film in which the material is dispersed and adsorbed and preferably further crosslinked with a crosslinking agent such as boric acid is widely used. Since such a polarizer is a uniaxially stretched PVA-based film, it easily contracts under high humidity. Therefore, a protective film is bonded to the polarizer for the purpose of supplementing moisture resistance and strength.

  As such a protective film, thermoplastic resins such as cellulose resin, polycarbonate resin, cyclic polyolefin resin, (meth) acrylic resin, and polyester resin are transparent, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. In particular, a protective film made of a triacetyl cellulose (TAC) resin has been widely used.

  These protective films are bonded to the polarizer by an adhesive, and as such an adhesive, from the viewpoint of adhesiveness to a polarizer having a hydrophilic surface, it is the same as the PVA resin aqueous solution, particularly the polarizer. A PVA resin aqueous solution mainly composed of a high saponification degree PVA resin is preferably used.

  By the way, in recent years, thinning of a polarizing plate has been demanded, and instead of a TAC film that has been most commonly used as a protective film, an acrylic film or a cyclic polyolefin resin film is used. However, these protective films instead of the TAC film cannot be firmly bonded to the polarizer using a conventional PVA adhesive. Therefore, various adhesives suitable for laminating protective films such as acrylic films and cyclic polyolefin resin films have been developed as alternatives to PVA adhesives.

  In addition, since the PVA adhesive is used as a solution or dispersion using water, it is necessary to dry the water when the adhesive is cured, and it takes a long time to dry the water. Accordingly, there has been a demand for improvement in that the drying efficiency is poor and the production efficiency of the polarizing plate is lowered.

  For example, Patent Document 1 proposes an adhesive composed of a composition containing an epoxy resin that does not contain an aromatic ring as a main component and a photocationic polymerization initiator. Such an adhesive is cationic polymerization by irradiation with active energy rays. Even if a resin film with low moisture permeability is used as the protective film, the protective film is applied to one or both sides of the polarizer with sufficient adhesive strength without causing problems such as poor appearance. It is described that a combined polarizing plate can be provided.

  Moreover, in patent document 2, the active energy ray hardening-type adhesive composition containing 3 types of radically polymerizable compounds from which SP value differs as a hardening component is excellent in adhesiveness of a polarizer and a protective film, and durability, It has been proposed as an adhesive with excellent water resistance.

  Furthermore, in Patent Document 3, 4-butylhydroxy acrylate: 20 to 90% by weight, ω-carboxy-polycaprolactone acrylate: 1 to 70% by weight, other radical polymerizable compound: 0 to 15% by weight, photopolymerization initiator : 0.01-20% by weight, Silane coupling agent: 0-10% by weight, radically polymerizable adhesive for forming a polarizing plate such that the glass transition temperature after curing is -80 to 0 ° C A composition has been proposed, and by using the adhesive composition, a PVA polarizer and a hard-to-adhere protective film typified by an acrylic film or a cycloolefin film are used as constituent layers, and the adhesive strength It is said that it is a polarizing plate which can form the small polarizing plate piece which is large and is excellent in durability, and is excellent in the punching workability.

  Patent Document 4 discloses an ultraviolet curable composition containing a (meth) acrylamide compound having no hydroxyl group, a (meth) acrylic acid alkyl ester compound having a hydroxyl group, boric acid and a photopolymerization initiator. It has been proposed that by using the adhesive composition, an ultraviolet curable composition having excellent adhesive strength can be obtained not only for various protective films but also for acrylic resin films.

JP 2004-245925 A JP 2012-144690 A JP 2010-282161 A JP2013-194082A

  However, the adhesive of Patent Document 1 uses a cationic polymerizable UV curable adhesive instead of a water-based adhesive. However, the cationic polymerizable UV curable adhesive has a dark reaction after UV irradiation. Therefore, when a long cured product is formed into a take-up roll, there is a problem that curling tends to occur during storage. In addition, the cationic polymerizable ultraviolet curable adhesive has a problem that it is easily affected by humidity during curing and the cured state tends to vary.

  In the radical polymerizable ultraviolet curable adhesive of Patent Document 2 described above, the adhesive layer is relatively hard, resulting in a decrease in adhesive strength over time, which is not satisfactory in terms of punching resistance and durability. There wasn't.

  In the radical polymerizable adhesive composition of the above-mentioned Patent Document 3, since the shrinkage is accompanied by curing shrinkage when the (meth) acrylic acid monomer is cured, the stability of the initial adhesion is lowered and the adhesive force is not sufficient.

  The ultraviolet curable composition of Patent Document 4 shows an adhesive force to the acrylic resin film, but the adhesive force to the polarizer is not sufficient and the color loss resistance is weak.

  Therefore, although the active energy ray-curable adhesive does not require a drying step and the production efficiency is higher than the PVA adhesive used as an aqueous solution, it can sufficiently bond various protective films for polarizing plates and polarizers. Was difficult and further improvement was required.

  In recent years, there has also been a problem that color loss (discoloration) occurs when a polarizing plate is left under high temperature and high humidity for a long time. For example, it is a more severe evaluation, but it is immersed in warm water. Therefore, there is a demand for a polarizing plate that does not lose color or has reduced color loss even in such a state. As a method for obtaining such a polarizing plate excellent in color fading resistance, in the situation where improvement of an adhesive for laminating a polarizer and a protective film is also required, the adhesion described in Patent Documents 1 to 4 above. In the case of the agent, such color loss resistance cannot be obtained.

  Therefore, in the present invention, under such a background, the adhesive is excellent in adhesive force, and is suitable for bonding various protective films for polarizing plates and polarizers, in particular, protective films other than TAC and polarizers. An object of the present invention is to provide an adhesive composition for polarizing plates which is excellent in production efficiency and also excellent in resistance to color loss.

  However, the present inventors have made extensive studies in view of such circumstances, and as a result, in an adhesive composition for an active energy ray-curable polarizing plate, a metal or semi-metal chelate compound is present when it becomes an adhesive. As a result, it was found that the polarizer and the protective film were excellent in adhesion, and further, the color fading resistance of the polarizing plate was excellent, and the present invention was completed.

  That is, the gist of the present invention is that a chelate-forming metal or metalloid compound (A), a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid, and urethane (meta). The present invention relates to an adhesive composition for polarizing plates comprising an acrylate compound (C), and a chelate-forming metal or metalloid compound (A) and a function capable of chelating with the metal or metalloid. Relating to an adhesive composition for a polarizing plate comprising a chelate compound (AB) formed from a photopolymerizable compound (B) containing a group and a urethane (meth) acrylate compound (C) It is.

  Furthermore, the present invention also provides a polarizing plate adhesive obtained by curing the polarizing plate adhesive composition, and a polarizing plate in which a polarizer and a protective film are bonded together via the polarizing plate adhesive. To do.

  Here, in the present invention, it is important that a metal or metalloid chelate compound is present and further a urethane (meth) acrylate compound (C) is blended, but it has a metal or metalloid chelate compound. Thus, the hydroxyl group on the PVA surface forming the polarizer and the chelating functional group in the adhesive form a chemical bond to increase the adhesive strength between the polarizer and the protective film, and iodine in the polarizer. It is presumed that the anti-color loss property of the polarizing plate is improved in order to prevent diffusion of the polarizing plate. Furthermore, by having a urethane (meth) acrylate compound (C), curing shrinkage can be alleviated, and by being multifunctional, the degree of crosslinking is improved, the adhesive strength is further increased, and the water resistance is improved. It is presumed to be a plan. It is presumed that the urethane (meth) acrylate compound (C) is polyfunctional but has a polymer portion (having a certain molecular weight due to the repeating structure of the polyol portion), and thus is crosslinked. This is because it is considered that curing shrinkage can be reduced while increasing the degree.

  The adhesive composition for polarizing plates of the present invention has high production efficiency of polarizing plates, and various protective films for polarizing plates and polarizers, particularly protections other than TAC such as acrylic films and cyclic polyolefin resin films. A polarizing plate that can sufficiently bond a film and a polarizer, and further has excellent anti-color loss resistance in which color loss is suppressed even when the polarizing plate is immersed in high temperature and high humidity or warm water. 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.
The acrylic monomer is a monomer having at least one of an acryloyl group and a methacryloyl group, and the acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one acrylic monomer.

(Adhesive composition for polarizing plate)
The adhesive composition for polarizing plates of the present invention (hereinafter sometimes referred to as “adhesive composition”) is:
[I] A metal or metalloid compound (A) capable of chelation, a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid, and a urethane (meth) acrylate compound (C )), And
Also,
[II] A chelate compound (AB) formed from a chelate-forming metal or metalloid compound (A) and a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid And a urethane (meth) acrylate compound (C).

<Metal or metalloid compound (A) capable of chelate formation>
The chelate-forming metal or metalloid compound (A) used in the present invention is not particularly limited as long as it can form a chelate with the photopolymerizable compound (B) described later. For example, a metal or metalloid alcoholate , A hydrolyzate of the alcoholate, a condensate of the alcoholate, a chelate compound of the alcoholate, a partial alcoholate of the chelate compound, and a metal or metalloid acylate. In particular, metal or metalloid alcoholates and chelate compounds of the alcoholates are preferable. Particularly, metal or metalloid alcoholates represented by the following general formula (1), and chelate compounds of the alcoholates Is preferably used.
In addition, as a metal or metalloid compound (A) which can form a chelate, only 1 type may be used from the said compound, and arbitrary 2 or more types may be used together.

(Wherein M represents a metal or metalloid atom, R ¹ represents a monovalent organic group having 1 to 10 carbon atoms which may be the same or different, and R ² represents hydrogen which may be the same or different. Or an alkyl group having 1 to 5 carbon atoms, an acyl group having 1 to 6 carbon atoms, or a phenyl group, m and n each represents an integer of 0 or more, and m + n represents a valence of M.)

  In the general formula (1), examples of the metal or metalloid atom represented by M include transition metal, group 2, group 12, group 13, and group 14 metal or metalloid elements. Boron, silicon, aluminum, zirconium, titanium, magnesium, chromium, cobalt, copper, iron, nickel, vanadyl, zinc, indium, calcium, manganese, tin are preferred, and boron, silicon, aluminum, titanium, chromium, copper, Iron, nickel, zinc and indium are preferred. In general, divalent to tetravalent metals or metalloids are used, and boron, silicon, aluminum, titanium and zirconium are particularly preferably used. Further, it is most preferable that the alcoholate or acylate is in a liquid state and boron or silicon is used from the viewpoint of convenience of handling. Moreover, even if it is a solid state, it should just be easily soluble in the photopolymerizable compound (D).

In the general formula (1), as the monovalent organic group having 1 to 10 carbon atoms represented by R ¹ , when the general formula (1) is a metal or semimetal alcoholate, for example, methyl Group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-hexyl group, n-heptyl group, n-octyl group, Alkyl groups such as 2-ethylhexyl group; acyl groups such as acetyl group, propionyl group, butyryl group, valeryl group, benzoyl group, trioyl group; vinyl group, allyl group, cyclohexyl group, phenyl group, glycidyl group, (meth) acrylic group In addition to oxy groups, ureido groups, amide groups, fluoroacetamide groups, isocyanate groups, etc., substituted derivatives of these groups can be mentioned. Examples of the substituent in the substituted derivative include a halogen atom, a substituted or unsubstituted amino group, a hydroxyl group, a mercapto group, an isocyanate group, a glycidoxy group, a 3,4-epoxycyclohexyl group, a (meth) acryloxy group, and a ureido group. And ammonium base. However, the carbon number of R ¹ composed of these substituted derivatives is 10 or less including the carbon atom in the substituent.

In addition, as R ¹ when the general formula (1) is a metal or metalloid acylate, for example, an acetoxyl group, a propionyloxyl group, a butyryloxyl group, a valeryloxyl group, a benzoyloxyl group, a trioyloxyl group Of the acyloxyl group.
In the above general formula (1), when two or more R ^{1 s} are present, they may be the same or different from each other, but are preferably the same.

In the general formula (1), examples of the alkyl group having 1 to 5 carbon atoms represented by R ² include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, sec- A butyl group, a t-butyl group, an n-pentyl group, and the like can be exemplified. Examples of the acyl group having 1 to 6 carbon atoms include an acetyl group, a propionyl group, a butyryl group, a valeryl group, and a caproyl group. Can do. Moreover, what is represented by R ² may be hydrogen.
In the general formula (1), when a plurality of R ² are present, they may be the same or different from each other, but the same is preferable.

The hydrolyzate of metal or metalloid alcoholate in the present invention is a product obtained by hydrolyzing the OR ² group contained in the metal or metalloid alcoholate of the general formula (1). It is not necessary that all OR ² contained in the alcoholate is hydrolyzed, for example, only one of them is hydrolyzed, two or more are hydrolyzed, or a mixture thereof. May be.

  The condensate of metal or metalloid alcoholate in the present invention is a product in which the hydrolyzate of metal or metalloid alcoholate is condensed to have a MOM structure. It is not necessary that all the hydroxyl groups of the hydrolyzate are condensed, and it is a concept that includes a mixture of a small part of the hydroxyl groups, a mixture of those having different degrees of condensation, and the like.

  The metal or metalloid alcoholate chelate compound in the present invention is a compound having a structure in which at least one of metal or metalloid alcoholate ligands is chelate-bonded. Such metal or metalloid alcoholate chelate compounds include metal or metalloid alcoholates and β-diketones, β-ketoesters, hydroxycarboxylic acids, hydroxycarboxylates, hydroxycarboxylic acid esters, ketoalcohols and aminoalcohols. It is preferably obtained by reaction with at least one selected compound.

  Among these compounds, β-diketones or β-ketoesters are preferably used, and specific examples thereof include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i- Propyl, acetoacetate-n-butyl, acetoacetate-sec-butyl, acetoacetate-t-butyl, 2,4-hexane-dione, 2,4-heptane-dione, 3,5-heptane-dione, 2,4 -Octane-dione, 2,4-nonane-dione, 5-methyl-hexane-dione and the like can be mentioned. Of these, acetylacetone and ethyl acetoacetate are particularly preferably used.

The hydrolyzate of the chelate compound in the present invention is not necessarily required to hydrolyze all the OR ² groups contained in the chelate compound, like the hydrolyzate of the metal or metalloid alcoholate described above. Only one may be hydrolyzed, two or more may be hydrolyzed, or a mixture thereof.

  The metal or metalloid acylate in the present invention is one in which at least one of the ligands of the metal or metalloid alcoholate is an acyloxyl group.

Among these chelate-forming metal or metalloid compounds (A), as specific examples of metal or metalloid alcoholates and metal or metalloid alcoholate chelate compounds,
[1] Boron compounds such as boric acid, trimethyl borate, triethyl borate, tributyl borate (including normal, iso, tertiary, secondary), tripropyl borate, triisopropyl borate, trimethyl carbitol borate;

[2] Titanium hydroxide, tetraethoxy titanium, triethoxy acetylacetonato titanium, diethoxy bis (acetylacetonato) titanium, ethoxy tris (acetylacetonato) titanium, tetrakis (acetylacetonato) titanium, tetrapropoxy titanium, Tripropoxy acetylacetonato titanium, dipropoxy bis (acetylacetonato) titanium, propoxy tris (acetylacetonato) titanium, tetrabutoxy titanium, tributoxy acetylacetonato titanium, dibutoxy bis (acetylacetonato) titanium, butoxy・ Tris (acetylacetonate) titanium, triethoxy ethylacetoacetate titanium, diethoxy bis Ethyl acetoacetate) titanium, ethoxy tris (ethyl acetoacetate) titanium, tetrakis (ethyl acetoacetate) titanium, tripropoxy ethyl acetoacetate titanium, dipropoxy bis (ethyl acetoacetate) titanium, propoxy tris (ethyl acetoacetate) Titanium compounds such as titanium, tributoxy ethyl acetoacetate titanium, dibutoxy bis (ethyl acetoacetate) titanium, butoxy tris (ethyl acetoacetate) titanium;

[3] Aluminum hydroxide, triethoxyaluminum, diethoxy-acetylacetonate aluminum, ethoxy-bis (acetylacetonato) aluminum, tris (acetylacetonato) aluminum, tripropoxyaluminum, dipropoxy-acetylacetonatoaluminum, propoxy-bis (Acetylacetonato) aluminum, tributoxyaluminum, dibutoxy-acetylacetonatoaluminum, butoxybis (acetylacetonato) aluminum, diethoxyethylacetoacetate aluminum, ethoxybis (ethylacetoacetate) aluminum, tris (ethylacetoacetate) ) Aluminum, dipropoxy ethyl acetoacetate aluminum, propoxy bis Le acetoacetate) aluminum, dibutoxy ethylacetoacetate aluminum, aluminum compounds such as butoxy-bis (ethylacetoacetate) aluminum;

[4] Zinc hydroxide, diethoxy zinc, ethoxy / acetyl acetonate zinc, bis (acetyl acetonate) zinc, dipropoxy zinc, propoxy / acetyl acetonate zinc, dibutoxy zinc, butoxy / acetyl acetonate zinc, ethoxy / ethyl acetoacetate Zinc compounds such as zinc, bis (ethyl acetoacetate) zinc, propoxy-ethyl acetoacetate zinc, butoxy-ethyl acetoacetate zinc;

[5] Tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, etc. Silicon compounds such as tetraalkoxysilane and compounds obtained by hydrolyzing (condensing) them;
Can be mentioned.

  Among these metal or metalloid alcoholates and chelate compounds, preferred are boric acid, trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, aluminum hydroxide, triethoxyaluminum, tripropoxyaluminum, tributoxy. Aluminum, dipropoxy-ethyl acetoacetate aluminum, tris (ethyl acetoacetate) aluminum, tris (acetylacetonato) aluminum, titanium hydroxide, dibutoxy bis (acetylacetonato) titanium, dipropoxy bis (acetylacetonato) titanium, diethoxy・ Bis (acetylacetonato) titanium, dibutoxy ・ bis (ethylacetoacetate) titanium, dipropoxy bis (d (Ruacetoacetate) titanium, diethoxy bis (ethylacetoacetate) titanium, zinc hydroxide, di (acetylacetonato) zinc, and di (ethylacetoacetate) zinc. Particularly preferred compounds are boric acid and trimethylborate. Triethyl borate, tripropyl borate, tributyl borate, aluminum hydroxide, tripropoxyaluminum, tris (acetylacetonato) aluminum, dibutoxy bis (acetylacetonato) titanium, di (acetylacetonato) zinc and the like. Furthermore, boric acid, trimethyl borate, and triethyl borate from the viewpoint of convenience in handling at a room temperature, solubility in the photopolymerizable compound (D), and reactivity with the hydroxyl group of the PVA resin forming the polarizer. Most preferred are trialkyl borates having an alkyl group having 1 to 5 carbon atoms such as tripropyl borate and tributyl borate, particularly tributyl borate.

  Specific examples of metal or metalloid acylates include dihydroxy titanium dibutyrate, di-i-propoxy titanium diacetate, di-i-propoxy titanium dipropionate, and di-i-propoxy titanium dimaloniate. And di-i-propoxy-titanium dibenzoylate, di-n-butoxy-zirconium diacetate, di-i-propylaluminum monomalonate and the like. Particularly preferred compounds are dihydroxy-titanium dibutyrate, di- -Titanium compounds such as i-propoxy-titanium diacetate.

<Photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid>
Further, the photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid used in the present invention may be a compound having the functional group and an ethylenically unsaturated group.

  Examples of the functional group capable of forming a chelate with the above metal or metalloid include a functional group having a β-diketone structure and a β-diketone structure such as acetoacetyl group and malonic acid ester. An acetoacetyl group is preferred from the viewpoint of convenience and reactivity with a hydroxyl group.

  In the present invention, when the photopolymerizable compound (B) containing a functional group capable of chelating with a metal or a metalloid is an acetoacetyl group-containing ethylenically unsaturated compound (b1), for example, it is produced by the following method. can do.

(I) A diketene is reacted with the functional group-containing ethylenically unsaturated compound (i). Examples of the functional group include a hydroxyl group, an amide group, a urethane group, an amino group, and a carboxyl group, and those suitable as the functional group-containing ethylenically unsaturated compound (i) include an alkylene group having 1 to 10 carbon atoms. Aliphatic acetoacetyl group-containing alkyl (meth) acrylate compounds having 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2-hydroxy-3 -(Meth) acrylates having a C1-C5 hydroxyalkyl group such as chloropropyl (meth) acrylate.

(II) The functional group-containing ethylenically unsaturated compound (i) is transesterified with acetoacetate.

In the case of (I) above, the reaction of diketene is non-catalytic, as well as the presence of tertiary amines, acids (sulfuric acid, etc.), basic salts (sodium acetate, etc.), organometallic compounds (dibutyltin laurate, etc.) Can be done below.
The reaction of (II) acetoacetate is preferably performed in the presence of a transesterification catalyst such as calcium acetate, zinc acetate, lead oxide or the like.
Among the above functional group-containing ethylenically unsaturated compounds (i), a (meth) acrylate having a hydroxyalkyl group is preferable from the viewpoints of versatility and convenience, production stability, and storage stability.

<Urethane (meth) acrylate compound (C)>
As said urethane (meth) acrylate type compound (C) used by this invention, a hydroxyl-containing (meth) acrylate type compound (c1), a polyvalent isocyanate type compound (c2), and a polyol type compound (c3) are made to react. (C2) obtained by reacting a hydroxyl group-containing (meth) acrylate compound (c1) and a polyvalent isocyanate compound (c2). Among these, a urethane (meth) acrylate compound (C1) obtained by reacting a hydroxyl group-containing (meth) acrylate compound (c1), a polyvalent isocyanate compound (c2), and a polyol compound (c3) is particularly preferable.

  The weight average molecular weight of the urethane (meth) acrylate compound (C) used in the present invention is preferably 500 to 50000, more preferably 1000 to 30000. If the weight average molecular weight is too small, curing shrinkage tends to increase and the adhesive force tends to decrease, and if too large, the water resistance tends to decrease.

In addition, said weight average molecular weight is a weight average molecular weight by standard polystyrene molecular weight conversion, column: Shodex GPC KF-806L (exclusion) in a high performance liquid chromatography (Showa Denko Co., Ltd. make, "Shodex GPC system-11 type | mold"). Limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plate / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) Measured by using series.

The viscosity of the urethane (meth) acrylate compound (C) at 60 ° C. is preferably 500 to 150,000 mPa · s, particularly preferably 500 to 120,000 mPa · s, and further preferably 1000 to 100,000 mPa. -S. When the viscosity is out of the above range, the coatability tends to be lowered.
The viscosity is measured with an E-type viscometer.

  Examples of the hydroxyl group-containing (meth) acrylate compound (c1) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). Acrylate, hydroxyalkyl (meth) acrylate such as 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethylacryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl (meth) ) Acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) Acrylate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, glycerin di (meth) acrylate, 2-hydroxy-3-acryloyl-oxypropyl methacrylate, pentaerythritol tri (meth) acrylate, caprolactone-modified penta Erythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, etc. Is mentioned.

Among these, a hydroxyl group (meth) acrylate compound having one ethylenically unsaturated group is preferable because it can relieve curing shrinkage at the time of coating film formation, and more preferably 2-hydroxyethyl (meth). It is a hydroxyalkyl (meth) acrylate such as acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, particularly It is preferable to use 2-hydroxyethyl (meth) acrylate in terms of excellent reactivity and versatility.
Moreover, these can be used 1 type or in combination of 2 or more types.

  Examples of the polyvalent isocyanate compound (c2) include aromatics such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate. Aliphatic polyisocyanates such as polyisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (Isocyanate methyl) Cycloaliphatic polyisocyanates such as rhohexane, trimer compounds or multimeric compounds of these polyisocyanates, allophanate type polyisocyanates, burette type polyisocyanates, water-dispersed polyisocyanates (for example, “Aqua manufactured by Nippon Polyurethane Industry Co., Ltd.” Nate 100 ”,“ Aquanate 110 ”,“ Aquanate 200 ”,“ Aquanate 210 ”, etc.).

  Among these, from the point of little yellowing, aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1, An alicyclic diisocyanate such as 3-bis (isocyanatomethyl) cyclohexane is preferably used, and isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated xylylene diisocyanate are particularly preferably used in terms of low curing shrinkage. Preferably, isophorone diisocyanate is used in terms of excellent reactivity and versatility.

  Examples of the polyol compound (c3) include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, polybutadiene polyols, (meth) acrylic polyols, polysiloxane polyols, and the like.

  Examples of the polyether polyol include, for example, polyether glycols containing an alkylene structure such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, and polyhexamethylene glycol, and random or block copolymers of these polyalkylene glycols. Coalescence is mentioned.

  Examples of the polyester-based polyol include three types of components: a condensation polymer of a polyhydric alcohol and a polycarboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a polyhydric alcohol, a polycarboxylic acid, and a cyclic ester. And the like.

  Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylene diol, 1,3-tetramethylene diol, 2-methyl-1,3-trimethyl. Methylene diol, 1,5-pentamethylene diol, neopentyl glycol, 1,6-hexamethylene diol, 3-methyl-1,5-pentamethylene diol, 2,4-diethyl-1,5-pentamethylene diol, glycerin , Trimethylolpropane, trimethylolethane, cyclohexanediols (such as 1,4-cyclohexanediol), bisphenols (such as bisphenol A), and sugar alcohols (such as xylitol and sorbitol).

  Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; -Cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylene dicarboxylic acid, trimellitic acid, and the like.

  Examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone.

  Examples of the polycarbonate-based polyol include a reaction product of a polyhydric alcohol and phosgene; a ring-opening polymer of a cyclic carbonate (such as alkylene carbonate).

  Examples of the polyhydric alcohol include polyhydric alcohols exemplified in the description of the polyester-based polyol, and examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate, and the like. It is done.

  The polycarbonate-based polyol may be a compound having a carbonate bond in the molecule and a terminal being a hydroxyl group, and may have an ester bond together with the carbonate bond.

  Examples of the polyolefin-based polyol include those having a homopolymer or copolymer such as ethylene, propylene, and butene as a saturated hydrocarbon skeleton, and having a hydroxyl group at the molecular end.

Examples of the polybutadiene-based polyol include those having a butadiene copolymer as a hydrocarbon skeleton and having a hydroxyl group at the molecular end.
The polybutadiene-based polyol may be a hydrogenated polybutadiene polyol in which all or part of the ethylenically unsaturated groups contained in the structure thereof are hydrogenated.

  Examples of the (meth) acrylic polyol include those having at least two hydroxyl groups in the molecule of the polymer or copolymer of the (meth) acrylic acid ester. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic (Meth) acrylic acid alkyl esters such as 2-ethylhexyl acid, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, and the like.

  Examples of the polysiloxane-based polyol include dimethyl polysiloxane polyol and methylphenyl polysiloxane polyol.

  Among these, polyester-based polyols and polyether-based polyols are preferable, and polyester-based polyols are particularly preferable because they are excellent in mechanical properties such as flexibility during curing.

  As a weight average molecular weight of the said polyol type compound (c3), 500-8000 are preferable, Especially preferably, it is 550-5000, More preferably, it is 600-3000. If the molecular weight of the polyol-based compound (c3) is too large, the adhesive force tends to decrease, and if it is too small, the water resistance tends to decrease.

  In the present invention, the urethane (meth) acrylate compound (C) can be produced as follows. The following description is about the urethane (meth) acrylate compound (C1) obtained by reacting the hydroxyl group-containing (meth) acrylate compound (c1), the polyvalent isocyanate compound (c2) and the polyol compound (c3). However, the urethane (meth) acrylate compound (C2) obtained by reacting the hydroxyl group-containing (meth) acrylate compound (c1) and the polyvalent isocyanate compound (c2) is also produced by carrying out according to this method. it can.

  The production method of the urethane (meth) acrylate compound (C1) is usually the above hydroxyl group-containing (meth) acrylate compound (c1), polyisocyanate compound (c2), polyol compound (c3) in a reactor. The reaction product obtained by reacting the polyol compound (c3) and the polyvalent isocyanate compound (c2) in advance may be added to the hydroxyl group-containing (meth) acrylate compound (c1). ) Is useful in terms of reaction stability and reduction of by-products.

  For the reaction between the polyol compound (c3) and the polyvalent isocyanate compound (c2), known reaction means can be used. At that time, for example, the molar ratio of the isocyanate group in the polyvalent isocyanate compound (c2) to the hydroxyl group in the polyol compound (c3) is usually about 2n: (2n-2) (n is an integer of 2 or more). Thus, after obtaining the terminal isocyanate group-containing urethane (meth) acrylate compound having the isocyanate group remaining, the addition reaction with the hydroxyl group-containing (meth) acrylate compound (c1) is made possible.

  The addition reaction between the reaction product obtained by reacting the polyol compound (c3) and the polyvalent isocyanate compound (c2) in advance with the hydroxyl group-containing (meth) acrylate compound (c1) is also a known reaction. Means can be used.

  The reaction molar ratio between the reaction product and the hydroxyl group-containing (meth) acrylate compound (c1) is, for example, that the polyisocyanate compound (c2) has two isocyanate groups and the hydroxyl group-containing (meth) acrylate compound (c1). ) Has one hydroxyl group, the reaction product: hydroxyl group-containing (meth) acrylate compound (c1) is about 1: 2, and the polyisocyanate compound (c2) has three isocyanate groups. When the hydroxyl group-containing (meth) acrylate compound (c1) has one hydroxyl group, the reaction product: hydroxyl group-containing (meth) acrylate compound (c1) is about 1: 3.

  In the addition reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (c1), the reaction is terminated when the residual isocyanate group content in the reaction system is 0.5% by weight or less. A (meth) acrylate compound (C) is obtained.

  In the reaction between the polyol compound (c3) and the polyvalent isocyanate compound (c2), and further the reaction product and the hydroxyl group-containing (meth) acrylate compound (c1), a catalyst is used for the purpose of promoting the reaction. The catalyst is preferably an organic metal compound such as dibutyltin dilaurate, trimethyltin hydroxide, tetra-n-butyltin, zinc octoate, tin octoate, cobalt naphthenate, stannous chloride. Metal salts such as stannic chloride, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N ′, Amine catalysts such as N'-tetramethyl-1,3-butanediamine and N-ethylmorpholine, bismuth nitrate, bibromide In addition to trout, bismuth iodide, bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, lauryl Organic acid bismuth such as bismuth acid salt, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bis neodecanoate, bismuth disalicylate, bismuth digallate Examples thereof include bismuth-based catalysts such as salts, among which dibutyltin dilaurate and 1,8-diazabicyclo [5,4,0] undecene are preferable.

  In the reaction between the polyol compound (c3) and the polyvalent isocyanate compound (c2), and in the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (c1), it reacts with the isocyanate group. Organic solvents having no functional group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and organic solvents such as aromatics such as toluene and xylene can be used.

  Moreover, reaction temperature is 30-90 degreeC normally, Preferably it is 40-80 degreeC, and reaction time is 2 to 10 hours normally, Preferably it is 3 to 8 hours.

  The number of unsaturated groups of the urethane (meth) acrylate compound (C) used in the present invention is preferably 2 to 6, more preferably 2 to 4, and more preferably 2 in view of curing shrinkage.

  Moreover, in this invention, a polymer, an acid group containing monomer, and a photobase generator can be used suitably with the said urethane (meth) acrylate type-compound (C) component, Especially, using a polymer with (C) component. Is preferred.

  Examples of the polymer include a polymer that is at least one of an acrylic resin and a polymer containing a polyoxyalkylene chain. Examples of the acid group-containing monomer include (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, carboxyethyl acrylate, and the like. Further, as the photobase generator, one or more secondary amines, tertiary compounds that can function as a curing catalyst when the molecular structure is changed by light irradiation such as ultraviolet rays or visible light, or the molecules are cleaved. Examples of the compound that forms an amine salt include (E) -1- [3- (2-hydroxyphenyl) -2-propenoyl] piperidine, 9-anthrylmethyl-N, N-diethylcarbamate, and the like. These may be used alone or in combination of two or more. Moreover, it is preferable that these compounding quantities are 40 weight% or less of the whole composition, Most preferably, it is 20 weight% or less.

<Photopolymerizable compound (D)>
In the present invention, it is preferable from the viewpoints of coating property, curability, adhesiveness and the like that it further contains a photopolymerizable compound (D) (excluding the photopolymerizable compound (B)). .
As the photopolymerizable compound (D) used in the present invention, the photopolymerizable compound (B) is excluded, and an ethylenically unsaturated compound (d1) having one ethylenically unsaturated group and an ethylenically unsaturated compound are used. It is preferably at least one selected from the group of ethylenically unsaturated compounds (d2) having two or more saturated groups.

  Examples of the ethylenically unsaturated compound having one ethylenically unsaturated group (hereinafter sometimes abbreviated as “monofunctional monomer”) (d1) include styrene, vinyltoluene, chlorostyrene, and α-methylstyrene. , Methyl (meth) acrylate, ethyl (meth) acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, phenoxyethyl (meth) Acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerol mono (meth) acrylate, glycidyl ( Acrylate), lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, Dicyclopentanyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) ) Acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide modified (n = 2) (meth) acrylate, noni Half of phthalic acid derivatives such as ruphenol propylene oxide modified (n = 2.5) (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate ) Acrylate, furfuryl (meth) acrylate, carbitol (meth) acrylate, benzyl (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) acrylate, acryloylmorpholine, dimethylacrylamide, 2-hydroxyethylacrylamide, N-methylol (Meth) acrylamide, N-vinylpyrrolidone, 2-vinylpyridine, polyoxyethylene secondary alkyl ether acrylate, and the like.

  In addition, a Michael adduct of acrylic acid or 2-acryloyloxyethyldicarboxylic acid monoester can also be used in combination. As the Michael adduct of acrylic acid, acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid A trimer, an acrylic acid tetramer, a methacrylic acid tetramer, etc. are mentioned. The 2-acryloyloxyethyl dicarboxylic acid monoester is a carboxylic acid having a specific substituent, for example, 2-acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxy Examples thereof include ethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid monoester, and the like. Furthermore, other oligoester acrylates can also be mentioned.

  The ethylenically unsaturated compound having two or more ethylenically unsaturated groups (hereinafter sometimes abbreviated as “polyfunctional monomer”) (d2) includes a bifunctional monomer and a trifunctional or higher functional monomer. It is done.

  Examples of the bifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and 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, cyclohexanedimethanol di (meth) acrylate, Xylated cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,6-hexanediol 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 and the like.

Examples of the tri- or higher functional monomer include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth). ) Acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified triacrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol hexa ( (Meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, caprolact Modified pentaerythritol tetra (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, ethoxylated glycerin triacrylate and the like can be mentioned.
1 type may be used for a photopolymerizable compound (D) from the above, and it may use 2 or more types together.

  Thus, in the present invention, [I] a metal or metalloid compound (A) capable of forming a chelate, a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid, and a urethane (meta ) Adhesive composition for polarizing plate comprising acrylate compound (C) and preferably further containing other photopolymerizable compound (D) (excluding photopolymerizable compound (B)), [II] A chelate compound (AB) formed from a chelate-forming metal or metalloid compound (A) and a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid ), A urethane (meth) acrylate-based compound (C), and preferably a further photopolymerizable compound (D) (excluding the photopolymerizable compound (B)). Adhesive group And things.

  With regard to the blending ratio of (A) and (B), (A) / (B) is preferably 1/99 to 50/50 by weight, particularly 5/95 to 40/60, more preferably 10 / 90 to 30/70 is preferable. If the value of (A) / (B) is too small, there is a tendency that the adhesive force between the polarizer and the protective film is lowered and the color loss resistance is lowered, and if too large, the durability during the hot water resistance test is lowered. There is a tendency to invite.

  As for the blending ratio of (A) and (C), it is preferable that (A) / (C) is 1/99 to 40/60 in weight ratio, particularly 10/90 to 30/70, and further 15 It is preferable that it is / 85-25 / 75. If the value of (A) / (C) is too small, the adhesive force tends to decrease, and if too large, the adhesive force tends to decrease.

  In the case of the above [I], (A) to (D) can be appropriately blended to obtain an adhesive composition for a polarizing plate. About each content rate of (A)-(D), (A) is 0.1-30 weight% with respect to the sum total of (A)-(D), (B) is 0.01-30 weight%. , (C) is preferably 0.5 to 50% by weight, and (D) is preferably 30 to 99% by weight, in particular, (A) is 0.5 to 20% by weight and (B) is 0.05 to 20 wt%, (C) 1-40 wt%, (D) 50-98 wt%, (A) 1-15 wt%, (B) 0.1-10 wt%, (C ) Is preferably 4 to 30% by weight, and (D) is preferably 65 to 94% by weight. If the content of (A) is too small, the adhesive strength between the polarizer and the protective film tends to decrease and the color loss resistance tends to decrease. If the content is too large, the durability decreases during the hot water resistance test, and the polarization There exists a tendency for the adhesive force of a child and a protective film to fall. When there is too little content of this (B), there exists a tendency for the adhesive force of a polarizer and a protective film to fall, and when too large, there exists a tendency for the durability at the time of a hot water resistance test to fall. If the content of (C) is too small, the water resistance and adhesive strength tend to decrease, and if too large, the adhesive strength tends to decrease. When there is too little content of this (D), there exists a tendency for the durability at the time of a hot water test to fall, and when too much, there exists a tendency for the adhesive force of a polarizer and a protective film to fall.

  In the present invention, an adhesive composition for polarizing plate containing (A), (B) and (C), preferably (D), is applied to a polarizer, usually 50 to 200 ° C., particularly preferably. A chelate compound (AB) can be formed by drying at 60-150 degreeC. Moreover, after making it the adhesive composition for polarizing plates containing (A), (B) and (C), preferably (D), usually at 50 to 120 ° C., particularly preferably at 60 to 90 ° C. (A ) And (B) can be reacted to form a chelate compound (AB).

  In the case of [II], a chelate compound (AB) formed from (A) and (B), a urethane (meth) acrylate compound (C), and preferably (D). In addition, (A), (B), (C), a chelate compound (AB) formed from (A) and (B), and preferably (A), (B), (C), D) will also be contained.

The content of the chelate compound (AB) is preferably 0.1 to 40% by weight, particularly 0.5 to 30% by weight, and more preferably 1 to 20% by weight. .
If the content is too small, the adhesive force between the polarizer and the protective film tends to decrease and the color loss resistance tends to decrease. If the content is too large, the durability decreases during the hot water resistance test, and the polarizer and the protective film. There is a tendency for the adhesive strength of the steel to decrease.

  In forming such a chelate compound (AB), it is usually mixed at 20 to 120 ° C., particularly 30 to 80 ° C.

  In the present invention, the presence of the above-described metal or metalloid chelate compound exhibits an effect of excellent color fading resistance of the polarizing plate.

  In the adhesive composition for polarizing plates of the present invention, a polymerization initiator, a silane coupling agent, an antistatic agent, other acrylic adhesives, other adhesives, and a urethane resin as long as the effects of the present invention are not impaired. , Rosin, rosin ester, hydrogenated rosin ester, phenol resin, aromatic modified terpene resin, aliphatic petroleum resin, alicyclic petroleum resin, styrene resin, xylene resin, etc., plasticizer such as polyol Conventionally known additives such as coloring agents, colorants, fillers, anti-aging agents, ultraviolet absorbers, functional dyes, and compounds that cause coloration or discoloration upon irradiation with ultraviolet rays or radiation can be blended. The amount of these additives is preferably 30% by weight or less, particularly preferably 20% by weight or less, based on the total composition.

  In addition to the above additives, a small amount of impurities contained in the raw materials for producing the constituent components of the adhesive composition may be contained.

<Polymerization initiator (E)>
In the present invention, it is preferable to further contain a polymerization initiator (E) to cure the adhesive composition.
As the polymerization initiator (E), for example, various polymerization initiators such as a photopolymerization initiator (e1) and a thermal polymerization initiator (e2) can be used. It is preferable to use e1) in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  Further, when the photopolymerization initiator (e1) is used, the adhesive composition is cured by irradiation with active energy rays, and when the thermal polymerization initiator (e2) is used, the adhesive composition is cured by heating. However, it is also preferable to use both in combination as necessary.

  Examples of the photopolymerization initiator (e1) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Ben such as ether Ins; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy -3 Thioxanthones such as 4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl- And acyl phosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. In addition, these photoinitiators (e1) may be used individually by 1 type, and 2 or more types may be used together.

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

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

  Examples of the thermal polymerization initiator (e2) 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 -Di-t-butylperoxycyclohexyl) propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroper Oxide, t-butyl hydroperoxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-Butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexa Noyl peroxide, octanoyl per Oxide, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoyl benzoyl peroxide, benzoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butyl) (Cyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-s-butyl peroxydicarbonate, Di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-te Lamethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxy Pivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylper) Oxy) hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t- Hexyl peroxyisopropyl monocarbonate, t-butyl peroxyisobutyrate t-butyl peroxymalate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2 -Ethylhexyl monocarbonate, t-butyl peroxyacetate, t-butyl peroxy-m-toluylbenzoate, t-butyl peroxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5 -Bis (m-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilylper Oxide, 3,3 ', 4,4'-tetra Organic peroxide initiators such as (t-butylperoxycarbonyl) benzophenone and 2,3-dimethyl-2,3-diphenylbutane; 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1- [(1-cyano-1-methylethyl) azo] formamide, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′- Azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis (2-methyl- N-phenylpropionamidine) dihydrochloride, 2,2'-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] Hydride chloride, 2,2'-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride 2,2'-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2,2'-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) Lopan] dihydrochloride, 2,2'-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (5-hydroxy-3 , 4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] ] Propionamide], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide], 2,2'-azobis [2-me Til-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropionamide), 2,2'-azobis (2,4,4-trimethylpentane), 2,2'- Azobis (2-methylpropane), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl ) Propionitrile] and the like; and the like. In addition, only 1 type may be used independently for these thermal polymerization initiators, and 2 or more types may be used together.

  About content of the said polymerization initiator (E), 100 weight part of the sum total of said (A), (B) and (C) (when (D) is contained, the sum of (A)-(D)) The amount is preferably 0.5 to 20 parts by weight, particularly preferably 0.8 to 15 parts by weight, and more preferably 1 to 10 parts by weight. If the content of the polymerization initiator (E) is too small, the curability tends to be poor and the physical properties tend to become unstable. If the content is too large, the low molecular weight component increases and the crosslinking density decreases, resulting in water resistance and heat resistance. There is a tendency to decrease.

  Thus, the adhesive composition for polarizing plates of the present invention is obtained. The adhesive composition for polarizing plates of the present invention preferably functions as an adhesive when cured by irradiation with active energy rays, and is suitable as an adhesive for polarizing plates for bonding a polarizer and a protective film. It can be used for.

  The adhesive composition for polarizing plates of the present invention may contain a solvent or may be used as a solventless composition, but is used as a solventless composition in terms of excellent adhesive performance. Is better.

(Polarizer)
There is no restriction | limiting in particular as said polarizer, A well-known thing can be used.
For example, (i) A dichroic material such as iodine or a dichroic dye is adsorbed on a vinyl alcohol resin film such as a PVA film, a partially formalized PVA film, or an ethylene-vinyl alcohol resin film. Stretched (for example, see JP-A-2001-296427, JP-A-7-333426), (ii) a birefringent material having liquid crystallinity together with a dichroic material in the above (i) is a vinyl alcohol resin What is contained in the film (for example, see JP-A-2007-72203), (iii) A uniaxially stretched thermoplastic norbornene resin film containing a dichroic material (for example, JP-A-2001-356213) (Iv) PVA resin or ethylene-vinyl alcohol resin is dehydrated or deaceticated. Introducing a polyene structure continue, polyene-based film obtained by stretching them (e.g., see JP Patent 2007-17845.), And the like.
Among these, a uniaxially stretched film in which iodine is adsorbed on a PVA-based film is preferable because of excellent polarization characteristics.

  The thickness of such a polarizer is usually 0.1 to 100 μm, particularly 0.5 to 80 μm, more preferably 1 to 60 μm.

(Protective film)
The protective film can make up for deficiency in durability under high humidity, which is a problem of polarizers, by bonding to at least one surface, preferably both surfaces, of the polarizer.
Furthermore, the properties required for the protective film used in the present invention include transparency, mechanical strength, thermal stability, moisture shielding properties, optical isotropy, and the like.

As a material for such a protective film, a cellulose ester resin, a cyclic olefin resin, and a (meth) acrylic resin are preferably used from the viewpoints of optical properties and durability.
Other materials include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polystyrene resins such as polystyrene and acrylonitrile / styrene copolymers, polyolefin resins such as polyethylene and polypropylene, polyarylate resins, and polycarbonate resins. , Vinyl chloride resins, amide resins such as nylon and aromatic polyamide, (fluorine-containing) polyimide resins, polyether ether ketone resins, polyphenylene sulfide resins, vinylidene chloride resins, polyvinyl acetal resins such as polyvinyl butyral And polyoxymethylene resins and epoxy resins. These may be used alone or in combination of two or more.

  Typical examples of the cellulose ester resin used in the cellulose ester resin film include triacetyl cellulose and diacetyl cellulose, but other lower fatty acid esters of cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like. The mixed fatty acid ester can be used.

  Examples of the cyclic olefin resin used in the cyclic olefin resin film include norbornene resins. Such norbornene resins include, for example, ring-opening (co) polymers of norbornene monomers, addition-polymerized norbornene monomers, addition-copolymerized norbornene monomers and olefin monomers such as ethylene and α-olefins. Resin etc. are included.

  Specific examples of norbornene-based monomers include dimers such as norbornene and norbornadiene; tricyclics such as dicyclopentadiene and dihydroxypentadiene; heptacyclics such as tetracyclopentadiene; these methyl, ethyl, propyl and butyl Substituents such as alkyl, alkenyl such as vinyl, alkylidene such as ethylidene, aryl such as phenyl, tolyl, and naphthyl; and ester groups, ether groups, cyano groups, halogens, alkoxycarbonyl groups, pyridyl groups, hydroxyl groups, carvone Examples include substituents having groups containing elements other than carbon and hydrogen, such as acid groups, amino groups, hydroxyl-free groups, silyl groups, epoxy groups, acryloyl groups, and methacryloyl groups.

  Examples of commercially available cyclic olefin-based resin films include “ARTON” manufactured by JSR, “ZEONOR”, “ZEONEX” manufactured by Nippon Zeon, “OPTOREZ” manufactured by Hitachi Chemical, and “APEL” manufactured by Mitsui Chemicals. it can.

  Examples of the (meth) acrylic resin used in the (meth) acrylic resin film include poly (meth) acrylic acid esters such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, and methyl methacrylate. -(Meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer, polymer having alicyclic hydrocarbon group [For example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.], (meth) having a high glass transition temperature obtained by intramolecular crosslinking or intramolecular cyclization reaction Acrylic resins, rubber-acrylic graft type core-shell polymers, and the like can be mentioned.

  Examples of such commercially available (meth) acrylic resin films include “Acrypet VRL20A”, “Acrypet IRD-70” manufactured by Mitsubishi Rayon Co., Ltd., “MUX-60” manufactured by UMGABS, and the like.

  In addition, the protective film is subjected to surface hydrophilization treatment such as saponification treatment with an alkali solution for a film made of a cellulose ester resin or corona discharge treatment or plasma treatment for a film made of a cyclic olefin resin, as necessary. It may be what you did.

In addition, in order to improve the affinity with the adhesive on the surface of the protective film, it is possible to perform various surface treatments other than hydrophilization, and (meth) acrylic acid ester latex or styrene latex on the surface of the protective film, Examples thereof include an easy-adhesion layer and an anchor coat layer containing polyethyleneimine, polyurethane / polyester copolymer, etc., and a surface treatment method using a coupling agent such as a silane coupling agent and a titanium coupling agent. In addition, it is also possible to use together the above-mentioned various surface treatment methods.
Moreover, what coated the antistatic agent on the surface of the protective film or contained it in the film is also preferably used.

  Although the thickness of such a protective film is not particularly limited, a film thicker than the polarizer is usually used, and has a function of imparting strength as a base material of the polarizer, and is usually 10 to 100 μm, preferably 20 to 80 μm. is there.

  Further, such a protective film can be provided with a hard coat layer on the surface where the polarizer is not laminated, or can be subjected to various treatments such as anti-sticking, anti-reflection and anti-glare. Furthermore, various optical functional films such as a phase difference plate and a viewing angle widening film can be laminated.

(Polarizer)
The polarizing plate of the present invention is formed by laminating the above polarizer and a protective film via an adhesive for polarizing plates. Specifically, it is formed by laminating a protective film on at least one surface, preferably both surfaces, of the polarizer using the polarizing plate adhesive of the present invention. After a thing is uniformly apply | coated to a polarizer, a protective film, or both, both are bonded together, it crimps | bonds, and a polarizing plate is formed by performing active energy ray irradiation.

  When coating such an adhesive composition on a polarizer or a protective film, for example, reverse coater, gravure coater (direct, reverse or offset), bar reverse coater, roll coater, die coater, bar coater, rod coater, etc. Or can be applied by dipping.

  For such bonding and pressure bonding, for example, a roll laminator or the like can be used, and the pressure is selected from the range of 0.1 to 10 MPa.

  For such active energy ray irradiation, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X rays and γ rays, 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 even without using the said photoinitiator (e1).

A high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, an LED, or the like is used as a light source when performing such ultraviolet irradiation.
Such ultraviolet irradiation is performed under conditions of ^{2 to} 3000 mJ / cm ² , preferably 10 to 2000 mJ / cm ² .

Particularly if the high-pressure mercury lamp, for example, 5~3000mJ / cm ^2, preferably at the conditions of 50~2000mJ / cm ^2.
Moreover, in the case of the said electrodeless lamp, it is 2-2000 mJ / cm < ² >, for example, Preferably it carries out on the conditions of 10-1000 mJ / cm < ² >.

  The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but may be usually from several seconds to several tens of seconds, and in some cases, may be a fraction of a second. On the other hand, in the case of the electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 keV is used, and the irradiation amount is preferably 2 to 50 Mrad.

  The irradiation direction of such active energy rays (electron beam, ultraviolet ray, etc.) can be irradiated from any appropriate direction, but it is preferable to irradiate from the transparent protective film side in terms of preventing the polarizer from deteriorating.

  The thickness of the adhesive layer in the polarizing plate of the present invention obtained as described above is usually 0.01 to 10 μm, preferably 0.01 to 5 μm, particularly preferably 0.01 to 2 μm, more preferably 0.01 to 1 μm. It is. If the thickness is too thin, the cohesive force of the adhesive force itself cannot be obtained and the adhesive strength tends not to be obtained. If the thickness is too thick, the workability of the polarizing plate tends to be reduced due to cracks during punching.

  Since the adhesive composition for polarizing plates of the present invention becomes an adhesive having excellent adhesive strength at the initial stage and over time, various protective films for polarizing plates and polarizers, in particular, a protective film other than TAC and a polarizer can be attached. It is suitable for use in combination, and further, there is no need for a drying step, so that the production efficiency of the polarizing plate is excellent, and the color fading resistance of the polarizing plate is also excellent.

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

  The following components were prepared.

[Metal or metalloid compound (A) capable of chelating]
・ (A-1) Boric acid (manufactured by Wako Pure Chemical Industries, Ltd.)
(A-2) Tributyl borate (“Tri-n-butyl borate” manufactured by Kanto Chemical Co., Inc.)

[Photopolymerizable compound (B) containing functional group capable of chelating with metal or metalloid]
(B-1) 2-acetoacetoxyethyl methacrylate (“AAEM” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)

[Urethane (meth) acrylate compound (C)]
According to the following synthesis example 1, bifunctional polyether urethane acrylate (C-1) was synthesized.
(C-1) Bifunctional polyether urethane acrylate [Synthesis Example 1] In a 500 ml reaction vessel equipped with a stirrer, 0.3 g of dibutyltin dilaurate, 0.2 g of 4-methoxyphenol as a polymerization inhibitor, poly 230 g of tetramethylene glycol (molecular weight: 650) was charged, and the mixture was heated until the liquid temperature reached 40 ° C. while stirring.
185 g of hydrogenated diphenylmethane diisocyanate was gradually added to the reaction solution, and the temperature was raised to 60 ° C. over 1 hour. While continuing the reaction at 60 ° C. until the free NCO% becomes 7.0%, 85 g of 2-hydroxyethyl acrylate is added, and the reaction is continued until the free NCO% becomes 0.5% or less. A bifunctional polyether urethane acrylate (C-1) was obtained.
In addition, the weight average molecular weight of the obtained bifunctional polyether urethane acrylate (C-1) was 3200, and the viscosity in 60 degreeC was 14000 mPa * s.

[Photopolymerizable compound (D)]
・ (D-1) Acryloylmorpholine ("ACMO" manufactured by Kojin Co., Ltd.)
(D-2) Dimethylacrylamide (“DMAA” manufactured by Kojin Co., Ltd.)
(D-3) ethylene glycol diacrylate (“FA-222A” manufactured by Hitachi Chemical Co., Ltd.)

[Polymerization initiator (E)]
(E-1) 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by BASF)
(E-2) 2,4,6-trimethylbenzoyl-diphenylphosphine oxide ("Lucirin TPO" manufactured by BASF)

[Example 1]
<Preparation of adhesive composition for polarizing plate>
A flask for preparation was charged with 5 parts of boric acid (A-1), 5 parts of 2-acetoacetoxyethyl methacrylate (B-1), and 65 parts of dimethylacrylamide (D-2), heated to 60 ° C. and boric acid. Dissolve. Next, 5 parts of ethylene glycol diacrylate (D-3) and 20 parts of bifunctional polyether urethane acrylate (C-1) are added and mixed thoroughly. After cooling to room temperature, 1.5 parts of Irgacure 184 (E-1) and 1.5 parts of Lucillin TPO (E-2) were charged, mixed and dissolved to obtain an adhesive composition for polarizing plate.

[Examples 2-3, Comparative Examples 1-4]
A polarizing plate adhesive composition was prepared in the same manner as in Example 1 except that the blending components prepared above were blended in the proportions shown in Table 1 below.

<Preparation of polarizing plate test piece>
First, a 60 μm PVA film was stretched 1.5 times while immersed in a water bath with a water temperature of 30 ° C. Next, it was stretched 1.3 times while being immersed for 240 seconds in a dyeing tank (30 ° C.) consisting of 0.2 g / L of iodine and 15 g / L of potassium iodide, and further 50 g / L of boric acid and 30 g of potassium iodide. / L was immersed in a boric acid treatment tank (50 ° C.) and boric acid treatment was performed for 5 minutes while simultaneously uniaxially stretching 3.08 times. Thereafter, it was dried to produce a polarizer having a total draw ratio of 6 times.
Next, the adhesive composition for polarizing plate obtained above on an acrylic film (trade name “Acryprene” manufactured by Mitsubishi Rayon Co., Ltd.) having a size of 200 mm × 75 mm and a thickness of 75 μm is obtained with a bar coater (No. 10). After preparing two acrylic films with an adhesive composition layer coated so as to be laminated on both sides of the above polarizer having a size of 150 mm × 60 mm, they were bonded together using a roll machine at a nip pressure of 2 MPa, and a laminated film Got.
Next, from both sides on the acrylic film side of the laminated film, UV irradiation is performed with an ultraviolet irradiation device equipped with a high-pressure mercury lamp at a peak illuminance of 130 mW / cm ² and an integrated exposure amount of 900 mJ / cm ² (365 nm) to adhere. The agent composition was cured, and the obtained laminated film was used as a polarizing plate test piece.

  Performance evaluation was performed as follows using the polarizing plate test piece obtained above.

[Adhesiveness]
The polarizing plate test piece was cut into 120 mm × 25 mm, and the degree of adhesion between the acrylic film and the polarizer when the stress in the 90 ° direction was applied to the two acrylic films was evaluated according to the following criteria.
(Evaluation criteria)
◎… Strongly adhered ○… Adhered ×… Not adhered

[Color loss resistance]
The polarizing plate test piece was cut into 5 cm × 5 cm and immersed in warm water at 60 ° C., and the color tone of the polarizing plate test piece after 48 hours was observed and evaluated according to the following criteria.
○: Situation before the test and no change in color tone △… Slight color loss (fading) ×… Color loss completely (fading)

[water resistant]
The polarizing plate test piece was cut into 5 cm × 5 cm, immersed in warm water at 60 ° C., the adhesion of the polarizing plate test piece after 48 hours was observed, and evaluated according to the following criteria.
○: No peeling from the end of the test piece Δ: Peeling in the range of less than 5 mm from the end of the test piece ×: Peeling in the range of 5 mm or more from the end of the test piece

  Chelate-forming metal or metalloid compound (A), photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid, and urethane (meth) acrylate compound (C) The adhesive composition for polarizing plates of Examples 1 and 2 contained therein can sufficiently bond a polarizer and a protective film, and also has an excellent effect in resistance to color loss and water resistance. It was a thing. In contrast, Comparative Example 1 and Comparative Example 3 that do not contain a chelate-forming metal or metalloid compound (A), or a photopolymerizable compound (B) that contains a functional group capable of chelating with a metal or metalloid In the adhesive compositions of Comparative Example 2 and Comparative Example 4 that do not contain odor, not only the adhesiveness but also the color fading resistance and water resistance are inferior, and should be put to practical use as an adhesive composition for polarizing plates. It was something that could not be done. This shows that the adhesive composition for polarizing plates of this invention is very excellent.

  The polarizing plate adhesive composition of the present invention and the polarizing plate adhesive comprising such an adhesive composition are excellent in adhesiveness between the polarizer and the protective film, and also have excellent production efficiency without a drying step. In addition, it is excellent in color fading resistance of the polarizing plate, and not only for TAC films, but also for bonding protective films such as acrylic films and cyclic polyolefin resin films to polarizers. It is useful.

Claims (11)

  A metal or metalloid compound (A) capable of chelating, a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid, and a urethane (meth) acrylate compound (C) An adhesive composition for polarizing plates, comprising:   A chelate compound (AB) formed from a chelate-forming metal or metalloid compound (A) and a photopolymerizable compound (B) containing a functional group capable of chelating with the metal or metalloid, urethane An adhesive composition for polarizing plates, comprising a (meth) acrylate-based compound (C).   2. The chelate-forming metal or metalloid compound (A) is at least one selected from the group consisting of boron compounds, aluminum compounds, titanium compounds, zirconium compounds, zinc compounds and silicon compounds. Or the adhesive composition for polarizing plates of 2.   The photopolymerizable compound (B) containing a functional group capable of chelating with a metal or metalloid is an acetoacetyl group-containing ethylenically unsaturated compound (b1). The adhesive composition for polarizing plates as described in the paragraph.   The acetoacetyl group-containing ethylenically unsaturated compound (b1) is an aliphatic acetoacetyl group-containing alkyl (meth) acrylate compound having an alkylene group having 1 to 10 carbon atoms. An adhesive composition for polarizing plates.   The adhesive composition for polarizing plates according to any one of claims 1 to 5, further comprising a photopolymerizable compound (D) (excluding the photopolymerizable compound (B)). object.   The photopolymerizable compound (D) is selected from the group consisting of an ethylenically unsaturated compound (d1) having one ethylenically unsaturated group and an ethylenically unsaturated compound (d2) having two or more ethylenically unsaturated groups. The adhesive composition for polarizing plates according to claim 6, wherein the adhesive composition is at least one kind.   Furthermore, a polymerization initiator (E) is contained, The adhesive composition for polarizing plates as described in any one of Claims 1-7 characterized by the above-mentioned.   A polarizing plate adhesive obtained by curing the polarizing plate adhesive composition according to claim 1.   A polarizing plate adhesive comprising the polarizing plate adhesive composition according to any one of claims 1 to 8 cured by irradiation with active energy rays.   A polarizer and a protective film are bonded together through the polarizing plate adhesive according to claim 9 or 10.