JPWO2017090637A1 - Adhesive composition, polarizing plate adhesive composition, and polarizing plate using the same - Google Patents

Abstract

  A photopolymerizable compound (A) which is excellent in adhesive strength, suitable for laminating various protective films for polarizing plates and polarizers, and excellent in water resistance and color loss resistance. An adhesive composition containing an oxoacid (B), water (C), and polymer (D) comprising at least one member selected from the group consisting of group 13 metals and metalloid compounds.

Description

  The present invention relates to an adhesive composition, an adhesive composition for a polarizing plate, and a polarizing plate using the adhesive composition. The present invention relates to an adhesive composition used as an active energy ray-curable adhesive suitable for bonding.

  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 sealed, 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 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 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, there has been a demand for thinner polarizing plates, and acrylic films and cyclic olefin resin (COP) films have been used in place of TAC films that have been most commonly used as protective films. It has come to be. However, these protective films instead of the TAC film have a problem that it is difficult to firmly bond with a polarizer using a conventional PVA-based adhesive, or the appearance of the obtained polarizing plate is poor. . This is because the acrylic film and the COP film are more hydrophobic than the TAC film, and the moisture permeability is low, so that the water cannot be sufficiently dried. Therefore, various adhesives suitable for laminating protective films such as acrylic films and COP 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 when a resin film with low moisture permeability is used as a protective film, a 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.

  Moreover, in patent document 4, the (meth) acrylamide compound which does not have a hydroxyl group, boric acid, and a photoinitiator are contained, and 0.5-5 mass parts of said boric acid is used with respect to 100 mass parts of this acrylamide compound. An ultraviolet curable composition has been proposed, and by using the composition, an ultraviolet curable composition having excellent adhesive strength can be obtained not only for various protective films, but particularly for acrylic resin films. ing.

JP 2004-245925 A JP 2012-144690 A JP 2010-282161 A JP 2013-140883 A

  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 active energy ray-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 satisfactory in terms of punching resistance and durability. It was not a thing.
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.

  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.

  Further, in recent years, when the polarizing plate is left for a long time under high temperature and high humidity, the adhesive strength is lowered, and the protective film is peeled off or the polarizer is discolored (discolored). For example, even when immersed in warm water, the polarizer and the protective film do not peel off, and the polarizer does not lose color or lose color loss. Therefore, there is a demand for a polarizing plate having excellent resistance to color loss. As a method for obtaining a polarizing plate excellent in water resistance and color loss resistance, in the situation where improvement of an adhesive for bonding a polarizer and a protective film is also required, the above-mentioned Patent Documents 1 to In the adhesive No. 4, there was room for improvement in water resistance and color loss resistance, and the water resistance was particularly insufficient.

  Therefore, in the present invention, under such a background, it is an adhesive having excellent adhesive strength, suitable for bonding various protective films for polarizing plates and polarizers, and also for water resistance and color loss resistance. An adhesive composition capable of obtaining an excellent polarizing plate, an adhesive composition for polarizing plate, and a polarizing plate using the same are provided.

  However, as a result of intensive studies in view of such circumstances, the present inventors have found that, in the active energy ray-curable adhesive composition, the photopolymerizable compound (A) is the main component and the Group 13 metals and metalloids. By including at least one oxo acid (B), water (C), and polymer (D) selected from the group of compounds, the adhesive between the polarizer and various protective films is excellent. It was found to be excellent in water resistance and color loss resistance.

  That is, the gist of the present invention is that the photopolymerizable compound (A), at least one selected from the group consisting of group 13 metals and metalloid compounds, oxo acid (B), water (C), and polymer (D ) Containing an adhesive composition.

  Furthermore, this invention also provides the adhesive composition for polarizing plates using the said adhesive composition, and a polarizing plate using the same.

  Here, in the present invention, it is important to contain at least one oxo acid (B), water (C), and polymer (D) selected from the group 13 metal and metalloid compounds. However, this is focused on the moisture in the polarizer, which has not been noticed so far, and by using water, the moisture in the polarizer migrates to the surface of the polarizer, making the surface of the polarizer hydrophilic. This is intended to improve the adhesion between the polarizer and the adhesive layer.

  In general, when preparing an adhesive composition, if water remains, it is considered that a problem occurs in terms of adhesive strength. In the energy ray curable adhesive composition, since water itself does not participate in the photopolymerization reaction, it is not considered to further add water. However, in the present invention, the present inventors have found an unexpected effect that the water content of the polarizer is adjusted by the presence of water and the adhesive property between the polarizer and the protective film is excellent.

  Furthermore, by containing a polymer as an essential component, it is possible to obtain an adhesive composition that, when cured, suppresses curing shrinkage and provides an adhesive with excellent adhesive strength and water resistance.

  It should be noted that the amount of water used in the present invention is not an amount that hinders the performance of the polarizing plate, and does not need to be dried.

  The adhesive composition of the present invention comprises a photopolymerizable compound (A), an oxo acid (B) comprising at least one member selected from the group consisting of group 13 metals and metalloid compounds, water (C), and a polymer ( Since D) is contained, various protective films for polarizing plates and polarizers can be sufficiently bonded, and further, polarizing plates excellent in water resistance and color loss resistance can be obtained.

  The photopolymerizable compound (A) contains an unsaturated compound (A1) having one ethylenically unsaturated group, and the unsaturated compound (A1) having one ethylenically unsaturated group is proton accepting. When the photopolymerizable compound (A1-I) containing a group is included, the adhesiveness is improved.

  Further, when the photopolymerizable compound (A) contains an unsaturated compound (A2) having two or more ethylenically unsaturated groups, the water resistance and color loss resistance are further improved.

  Furthermore, when the content ratio of the unsaturated compound (A2) having two or more ethylenically unsaturated groups is 5 to 60% by weight in the photopolymerizable compound (A), the adhesiveness and water resistance and color loss are eliminated. It will become even better.

  Further, when the photopolymerizable compound (A) contains a urethane (meth) acrylate-based compound (A3), it can be more excellent in adhesiveness since the curing shrinkage can be reduced.

  And it becomes more excellent in adhesiveness and productivity that content of the said polymer (D) is 2-40 weight part with respect to 100 weight part of said photopolymerizable compounds (A).

  The adhesive composition for polarizing plates using the said adhesive composition can obtain the polarizing plate which was high in the production efficiency of a polarizing plate, and was excellent also in water resistance and color loss resistance.

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.

  The adhesive composition of the present invention comprises a photopolymerizable compound (A) as a main component and at least one selected from the group consisting of group 13 metals and metalloid compounds, oxoacid (B), water (C). And a polymer (D). Here, the main component usually means 50% by weight or more of the whole composition. Hereinafter, each component of the adhesive composition will be described in order.

<Photopolymerizable compound (A)>
The photopolymerizable compound (A) used in the present invention may be a photopolymerizable compound. For example, the unsaturated compound (A1) having one ethylenically unsaturated group (excluding (A3) described later). And unsaturated compounds (A2) having two or more ethylenically unsaturated groups (excluding (A3) described later) and urethane (meth) acrylate compounds (A3).
These photopolymerizable compounds (A) can be used alone or in combination of two or more.
A photopolymerizable compound (A) is a component for adjusting the physical property balance of adhesive composition, such as coating property, sclerosis | hardenability, adhesiveness.

<Unsaturated compound having one ethylenically unsaturated group (A1)>
As an unsaturated compound having one ethylenically unsaturated group (hereinafter, sometimes referred to as “monofunctional monomer”) (A1), for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, Alkyl (meth) acrylates such as isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate;
Such as cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc. Alicyclic (meth) acrylates;
(Meth) acrylate having an aromatic ring such as benzyl (meth) acrylate, phenol ethylene oxide modified (n = 2) (meth) acrylate, nonylphenol propylene oxide modified (n = 2.5) (meth) acrylate;
Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate;
Alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, butoxyethyl (meth) acrylate;
Amide group-containing (meth) acrylates such as dimethylacrylamide, 2-hydroxyethylacrylamide, N-methylol (meth) acrylamide;
Others, phenoxyethyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, glycerin mono Half of phthalic acid derivatives such as (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate ) Acrylate, furfuryl (meth) acrylate, carbitol (meth) acrylate, allyl (meth) acrylate, acryloylmorpholine, polyoxyethylene secondary alkyl ether acrylate ( Data) acrylate compound;
Styrene, vinyl toluene, chlorostyrene, α-methyl styrene, acrylonitrile, vinyl acetate, N-vinyl pyrrolidone, 2-vinyl pyridine and the like can be mentioned.

  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-acryloyl Examples thereof include oxyethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester, and 2-methacryloyloxyethyl hexahydrophthalic acid monoester. Furthermore, other oligoester acrylates can also be mentioned.

  In the present invention, it is preferable to use a monofunctional monomer (A1) from the viewpoint of coatability.

  The content of the monofunctional monomer (A1) in the photopolymerizable compound (A) is preferably 15 to 100% by weight, more preferably 20 to 95% by weight, and particularly preferably 25 to 90% by weight. If the content ratio of the monofunctional monomer (A1) is too small, the adhesiveness tends to decrease. In addition, when there is too much this content rate, there exists a tendency for water resistance to fall.

  In the present invention, the monofunctional monomer (A1) preferably includes a photopolymerizable compound (A1-I) containing a proton-accepting group from the viewpoint of adhesiveness. Further, the photopolymerizable compound (A1-I) containing a proton-accepting group is preferably a photopolymerizable compound containing a nitrogen atom in terms of compatibility, and in particular, photopolymerization containing an amide group. Preferably, it is a compound represented by the following general formula (1).

[Chemical formula 1]
^{_{CH 2 = C (R 1)}} -CONR 2 (R 3) ··· (1)
(In Formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms which may have a substituent. , R ³ represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, or R ² and R ³ may combine with each other to form a ring and contain an oxygen atom Further, a 5-membered ring or a 6-membered ring containing an oxygen atom may be formed, provided that R ² and R ³ do not simultaneously become a hydrogen atom.

As the compound represented by the general formula (1), for example,
N-alkyl (meth) acrylamides such as N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide;
N, N-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-ethylmethylacrylamide;
Hydroxyalkyl (meth) acrylamides such as N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxypropyl (meth) acrylamide;
Aminoalkyl (meth) acrylamides such as aminomethyl (meth) acrylamide and aminoethyl (meth) acrylamide;
Mercapto group-containing (meth) acrylamides such as mercaptomethyl (meth) acrylamide and mercaptoethyl (meth) acrylamide;
Cyclic amino (meth) acrylates such as N-acryloylmorpholine, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine;
Etc. Among these, N, N-dialkylacrylamides such as dimethylacrylamide and diethylacrylamide, and cyclic aminoacrylates such as N-acryloylmorpholine are preferable, and dimethylacrylamide is particularly preferable.

  In the present invention, the content (weight ratio) of the photopolymerizable compound (A1-I) containing a proton-accepting group in the photopolymerizable compound (A) is preferably 15 to 100% by weight, particularly It is preferably 20 to 95% by weight, more preferably 25 to 90% by weight. If the content of the photopolymerizable compound containing such a proton-accepting group is too low, the adhesive force with the polarizer and the protective film tends to be low.

  The content ratio (weight ratio) of the photopolymerizable compound (A1-I) containing a proton-accepting group in the monofunctional monomer (A1) is preferably 15 to 100% by weight, particularly 30 to 100%. It is preferable that it is weight%, Furthermore, it is 50 to 100 weight%. If the content of the photopolymerizable compound containing such a proton-accepting group is too low, the adhesive force with the polarizer and the protective film tends to be low.

<Unsaturated compound having two or more ethylenically unsaturated groups (A2)>
The ethylenically unsaturated compound having two or more ethylenically unsaturated groups (hereinafter sometimes referred to as “polyfunctional monomer”) (A2) has two ethylenically unsaturated groups ( Hereinafter, it may be described as “bifunctional monomer”), one having three or more ethylenically unsaturated groups (hereinafter, sometimes described as “trifunctional or higher monomer”), and the like.

  In the present invention, from the viewpoint of improving water resistance, it is preferable to use the polyfunctional monomer (A2) as the photopolymerizable compound (A), and among them, a trifunctional or higher functional monomer is preferable.

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, 1,6-hexanediol di (meta) ) Acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate DOO, diethylene glycol diglycidyl ether di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, di (meth) acrylate having a long chain or branched chain structure and the like;
Di (meth) acrylates having an alicyclic structure such as cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate;
Di (meth) acrylate having an aromatic ring such as diglycidyl phthalate di (meth) acrylate;
Alkyl modification such as ethylene oxide modified cyclohexanedimethanol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, isocyanuric acid ethylene oxide modified di (meth) acrylate Di (meth) acrylate having a ring structure such as di (meth) acrylate having a ring structure and the like;
Etc.

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, polyglycerin poly (meth) acrylate;
Caprolactone-modified dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, ethylene oxide-modified dipentaerythritol penta ( Alkyl such as (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, ethylene oxide modified glycerol tri (meth) acrylate Tri- or higher functional (meth) acrylate having a modified structure DOO, trifunctional or more (meth) acrylate having a long chain or branched chain structure and the like;
A tri (meth) acrylate having a ring structure such as isocyanuric acid ethylene oxide-modified triacrylate;
Etc.

  Among the above, the polyfunctional monomer (A2) is preferably a monomer having a ring structure such as an alicyclic ring, an aromatic ring or a nurate ring, or a monomer having an alkyl-modified structure, from the viewpoint of suppressing curing shrinkage. Tri (meth) acrylate having at least one of a ring structure and an alkyl-modified structure is preferable, and ethylene oxide-modified trimethylolpropane triacrylate and isocyanuric acid ethylene oxide-modified triacrylate are particularly preferable.

  The content of the polyfunctional monomer (A2) in the photopolymerizable compound (A) is preferably 5 to 60% by weight, more preferably 10 to 50% by weight, and particularly preferably 15 to 40% by weight. If the content ratio of the polyfunctional monomer (A2) is too large, the adhesiveness tends to decrease, and if it is too small, the water resistance tends to decrease.

<Urethane (meth) acrylate compound (A3)>
Moreover, in this invention, it is preferable to contain a urethane (meth) acrylate type compound (A3) at the point which can make small hardening shrinkage of the hardened | cured material when it hardens | cures.

  The urethane (meth) acrylate compound (A3) is obtained by reacting a hydroxyl group-containing (meth) acrylate compound (A3-1) or a polyvalent isocyanate compound (A3-2), or a hydroxyl group-containing (meth). Examples include those obtained by reacting an acrylate compound (A3-1), a polyvalent isocyanate compound (A3-2), and a polyol compound (A3-3). Among them, particularly preferred is a urethane (meth) acrylate compound obtained by reacting a hydroxyl group-containing (meth) acrylate compound (A3-1), a polyvalent isocyanate compound (A3-2), and a polyol compound (A3-3). It is.

  Examples of the hydroxyl group-containing (meth) acrylate compound (A3-1) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl. Hydroxyalkyl (meth) acrylate such as (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethylacryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxy Ethyl (meth) acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol (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 pentaerythritol 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 and the like.

  Among these, a hydroxyl group (meth) acrylate compound having 1 to 3 ethylenically unsaturated groups is preferable from the viewpoint of ensuring the flexibility of the cured product and excellent curability, and having one ethylenically unsaturated group. Compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylates such as 6-hydroxyhexyl (meth) acrylate, As a compound having two saturated groups, glycerin di (meth) acrylate, and as a compound having three ethylenically unsaturated groups, pentaerythritol tri (meth) acrylate is preferable in terms of excellent reactivity and versatility. Among these, compounds having one ethylenically unsaturated group are preferable from the viewpoint that the curing shrinkage of the cured product when cured can be reduced, and in particular, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meta) ) Acrylate is preferred.

Examples of the polyvalent isocyanate compound (A3-2) include:
Aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate;
Aliphatic polyisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate;
Cycloaliphatic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane;
Alternatively, trimer compounds or multimeric compounds of these polyisocyanates, allophanate-type polyisocyanates, burette-type polyisocyanates, water-dispersed polyisocyanates and the like can be mentioned.

  Among these, diisocyanate compounds are preferable from the viewpoint of stability during the urethanization reaction, and in particular, aliphatic diisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and hydrogenated diphenylmethane diisocyanate. , Cycloaliphatic polyisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane are preferably used, and more preferably isophorone diisocyanate in terms of low curing shrinkage, Hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and norbornene diisocyanate are used and are particularly preferred. The hydrogenated diphenylmethane diisocyanate in view of excellent reactivity and versatility, hydrogenated xylylene diisocyanate, isophorone diisocyanate is used.

  Examples of the polyol compound (A3-3) include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, polybutadiene polyols, (meth) acrylic polyols, polysiloxane polyols, and the like. .

  Examples of polyether polyols include polyether polyols containing alkylene structures such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, and polyhexamethylene glycol, and random or block copolymers of these polyalkylene glycols. Is mentioned.

  Examples of the polyester-based polyol include three types of components: a polycondensation product 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. Examples include reactants.

  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), sugar alcohols (such as xylitol and sorbitol), and the like.

  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, 1,4 -Arocyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylene dicarboxylic acid and trimellitic acid.

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

  Examples of the polycarbonate polyol include a reaction product of a polyhydric alcohol and phosgene, a ring-opening polymer of a cyclic carbonate (alkylene carbonate, etc.), and the like.

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

  In addition, the polycarbonate-type polyol should just be a compound which has a carbonate bond in a molecule | numerator, and the terminal is a hydroxyl group, and may have an ester bond with a 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 is 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 acid Examples include 2-ethylhexyl, (meth) acrylic acid decyl, (meth) acrylic acid dodecyl, (meth) acrylic acid alkyl esters such as octadecyl (meth) acrylic acid, and the like.

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

  Among these, polyester-based polyols and polyether-based polyols are preferable, and polyether-based polyols are particularly preferable in terms of flexibility of the cured product and compatibility with the photopolymerizable compound (A) and water (C). Polytetramethylene glycol is most preferred.

  In the present invention, the number average molecular weight of the polyol compound (A3-3) is preferably 250 to 3,000, particularly 250 to 2,000, and more preferably 250 to 1,000. If the number average molecular weight is too large, the crystallinity tends to be high and the viscosity tends to be high.

In addition, said number average molecular weight is a number average molecular weight by standard polystyrene molecular weight conversion, a column is put into a high performance liquid chromatography (Nippon Waters, "Waters 2695 (main body)" and "Waters 2414 (detector)"). : Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler It is measured by using three series of particle diameters: 10 μm).

  In the present invention, the urethane (meth) acrylate compound (A3) can be produced as follows. Although the following description is a description about what made a hydroxyl group containing (meth) acrylate type compound (A3-1), a polyvalent isocyanate type compound (A3-2), and a polyol type compound (A3-3) react. By carrying out according to this method, a product obtained by reacting a hydroxyl group-containing (meth) acrylate compound (A3-1) and a polyvalent isocyanate compound (A3-2) can also be produced.

  For example, (1) The above hydroxyl group-containing (meth) acrylate compound (A3-1), polyvalent isocyanate compound (A3-2), and polyol compound (A3-3) are charged into the reactor all at once or separately. A reaction method, (2) a hydroxyl group-containing (meth) acrylate compound (A3-) to a reaction product obtained by reacting a polyol compound (A3-3) and a polyvalent isocyanate compound (A3-2) in advance. 1) a method of reacting, (3) a polyol compound to a reaction product obtained by reacting a polyvalent isocyanate compound (A3-2) and a hydroxyl group-containing (meth) acrylate compound (A3-1) in advance. Although the method of making (A3-3) react, etc. are mentioned, Method (2) is preferable from points, such as stability of reaction and reduction of a by-product.

  A known reaction means can be used for the reaction of the polyol compound (A3-3) and the polyvalent isocyanate compound (A3-2). At that time, for example, the molar ratio of the isocyanate group in the polyvalent isocyanate compound (A3-2) to the hydroxyl group in the polyol compound (A3-3) is usually 2n: (2n-2) (n is 2 or more). By adjusting to an integer), a terminal isocyanate group-containing urethane (meth) acrylate compound having an isocyanate group remaining can be obtained. After obtaining the compound, a hydroxyl group-containing (meth) acrylate compound (A3-1) ).

  Addition reaction of a reaction product obtained by reacting the polyol compound (A3-3) and the polyvalent isocyanate compound (A3-2) in advance with a hydroxyl group-containing (meth) acrylate compound (A3-1) Also, known reaction means can be used.

  The reaction molar ratio between the reaction product and the hydroxyl group-containing (meth) acrylate compound (A3-1) is, for example, two isocyanate groups of the polyvalent isocyanate compound (A3-2), and the hydroxyl group-containing (meth) acrylate. When the number of hydroxyl groups of the system compound (A3-1) is 1, the reaction product: hydroxyl group-containing (meth) acrylate compound (A3-1) is about 1: 2, and the polyvalent isocyanate compound (A3- When the number of hydroxyl groups in the hydroxyl group-containing (meth) acrylate compound (A3-1) is one, the reaction product: hydroxyl group-containing (meth) acrylate compound (A3-1) Is about 1: 3.

  In the addition reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (A3-1), the reaction is terminated when the residual isocyanate group content in the reaction system is 0.5% by weight or less. A urethane (meth) acrylate compound (A3) is obtained.

  In the reaction between the polyol compound (A3-3) and the polyvalent isocyanate compound (A3-2), and the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (A3-1), the reaction It is also preferable to use a catalyst for the purpose of promoting the above, and examples of such a catalyst include organic metal compounds such as dibutyltin dilaurate, trimethyltin hydroxide, and tetra-n-butyltin, zinc octenoate, tin octenoate, and naphthenic acid. Metal salts such as cobalt, stannous chloride, stannic chloride, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N , N, N ', N'-tetramethyl-1,3-butanediamine, amine catalysts such as N-ethylmorpholine, bis nitrate Organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, 2-ethylhexanoic acid bismuth salt, naphthenic acid bismuth salt, isodecanoic acid bismuth salt, neodecanoic acid Bismuth salt, bismuth laurate, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, bismuth digallate, etc. Bismuth-based catalysts such as organic acid bismuth salts, inorganic zirconium, organic zirconium, zirconium-based catalysts such as zirconium alone, and a combination of two or more catalysts such as zinc 2-ethylhexanoate / zirconium tetraacetylacetonate It is, among others, dibutyltin dilaurate, 1,8-diazabicyclo [5,4,0] undecene is preferred. In addition, these catalysts can be used individually or in combination of 2 or more types.

  In the reaction between the polyol compound (A3-3) and the polyvalent isocyanate compound (A3-2), and the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (A3-1), Organic solvents that do not have functional groups that react with isocyanate groups, such as 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.

Thus, the urethane (meth) acrylate compound (A3) is obtained.
The weight average molecular weight of the urethane (meth) acrylate compound (A3) is preferably 1,000 to 60,000, particularly 1,500 to 50,000, more preferably 2,000 to 30,000. It is preferable. If the weight average molecular weight is too small, the cured shrinkage of the cured product tends to be large when cured, and if too large, the viscosity tends to be high and handling tends to be difficult.

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 urethane (meth) acrylate compound (A3) has a viscosity at 60 ° C. of preferably 500 to 100,000 mPa · s, particularly 800 to 50,000 mPa · s, It is preferable that it is 000-35,000 mPa * s. If the viscosity is too high, a large amount of diluent must be used, and workability tends to be reduced. If the viscosity is too low, adhesion tends to be reduced.
The viscosity is measured by an E-type viscometer.

  The content of the urethane (meth) acrylate compound (A3) in the photopolymerizable compound (A) is preferably 3 to 50% by weight, particularly 5 to 45% by weight, more preferably 8 to 40% by weight. Preferably there is. If the content is too small, the adhesiveness tends to decrease, and if it is too large, the viscosity is too high and workability tends to decrease.

<Oxo acid (B)>
The oxo acid (B) used in the present invention is at least one oxo acid selected from the group 13 metal and metalloid compounds (hereinafter sometimes simply referred to as “oxo acid”). It is often included for imparting adhesiveness.
Examples of the Group 13 metal and metalloid compound include boron, aluminum, gallium, indium, and thallium. Among them, in terms of solubility in the photopolymerizable compound (A) and adhesiveness. Boron is preferred.
Further, in the case of using a photopolymerizable compound (A1-I) containing a proton-accepting group as the photopolymerizable compound (A), the hydroxyl group in the polarizer and boric acid are cross-linked, Boron is also preferable from the viewpoint that the produced tetrahydroboric acid can be chemically bonded to a photopolymerizable compound containing a proton-accepting group to further improve the adhesion.
These oxo acids (B) can be used alone or in combination of two or more.

  The content of the oxo acid (B) is preferably 0.1 to 20 parts by weight, particularly 1 to 18 parts by weight, more preferably 1.5 to 100 parts by weight of the photopolymerizable compound (A). It is preferably -15 parts by weight, particularly 2-10 parts by weight. If the content of the oxo acid (B) is too small, the adhesive force between the polarizer and the protective film tends to be low, and if it is too large, the solubility in the photopolymerizable compound (A) tends to decrease. .

  In the case where the photopolymerizable compound (A) contains a photopolymerizable compound (A1-I) containing a proton-accepting group, the content of the oxo acid (B) is the light containing the proton-accepting group. The amount of the polymerizable compound (A1-I) is preferably from 0.1 to 100 parts by weight, particularly from 1 to 50 parts by weight, more preferably from 1.5 to 20 parts by weight, especially 100 parts by weight. It is preferable that it is 2-15 weight part. When the content of the oxo acid (B) is too small, the adhesive force between the polarizer and the protective film tends to be low. When the content is too large, the photopolymerizability containing the photopolymerizable compound (A) and the proton-accepting group is present. There exists a tendency for solubility with respect to a compound (A1-I) to fall.

<Water (C)>
The water (C) used in the present invention, for example, makes the surface layer of the polarizer hydrophilic, as an oxo acid (B) composed of at least one selected from the group 13 metal and metalloid compounds. When an acid is used, the tetrahydroboric acid produced by boric acid and water (C) is chemically bonded to the photopolymerizable compound (A1-I) containing a proton-accepting group, thereby adhering. In order to impart the function of improving the content.

  As such water (C), it is preferable to use water close to pure water from which impurities have been removed. For example, ion exchange water or the like is used. In addition, so-called industrial water can be used as long as it does not depart from the spirit of the present invention. In consideration of productivity and cost, industrial water, soft water, ion-exchanged water, or the like can be used in combination. preferable. Furthermore, in the present invention, it is better that the number of chlorine atoms is small, and it is preferable to use water having, for example, less than 0.5 ppm as residual chlorine.

  Further, the content of water (C) is preferably 0.01 to 30 parts by weight, particularly 0.5 to 25 parts by weight, and more preferably 100 parts by weight of the photopolymerizable compound (A). The amount is preferably 1 to 20 parts by weight, particularly 1.5 to 15 parts by weight. When there is too little content of this water (C), there exists a tendency for the adhesive force of a polarizer and a protective film to become low, and when too much, there exists a tendency for solubility with respect to a photopolymerizable compound (A) to fall.

  In addition, when the photopolymerizable compound (A1-I) containing a proton-accepting group is contained as the photopolymerizable compound (A), the content of water (C) is the photopolymerization containing the proton-accepting group. The amount is preferably 0.01 to 150 parts by weight, particularly 0.1 to 100 parts by weight, more preferably 1 to 50 parts by weight, in particular 1 to 100 parts by weight of the active compound (A1-I). It is preferably 5 to 20 parts by weight. If the water (C) content is too small, the adhesive force between the polarizer and the protective film tends to be low, and if it is too large, the photopolymerizable compound (A) and a photopolymerizable compound containing a proton-accepting group are present. There is a tendency not to dissolve in (A1-I).

  Furthermore, the content ratio (B / C) of the oxo acid (B) composed of at least one selected from the group 13 metal and metalloid compound to water (C) is 2/8 to 8 by weight. / 2, preferably 2.5 / 7.5 to 7.5 / 2.5, more preferably 3/7 to 7/3. If the content ratio (B / C) is too small or too large, the adhesive force between the polarizer and the protective film tends to be low.

  In the present invention, the content ratio of water (C) to the entire adhesive composition is preferably 1 to 8% by weight, more preferably 2 to 7% by weight, and particularly preferably 3 to 6% by weight. It is.

<Polymer (D)>
The polymer (D) used in the present invention is effective for suppressing curing shrinkage, particularly preferably a polymer having no ethylenically unsaturated group, and when the pressure-sensitive adhesive composition is cured, It does not undergo a polymerization reaction with the photopolymerizable compound (A), thereby suppressing curing shrinkage.

  About the weight average molecular weight of a polymer (D), it is preferable that the weight average molecular weight of a polymer is comparatively small, Usually, 500-1 million, Preferably it is 800-500,000, Most preferably, it is 1,000-100,000. It is. If the weight average molecular weight is too low, the adhesive force tends to decrease. If the weight average molecular weight is too high, the compatibility is decreased and the stability as the adhesive composition is decreased, or the viscosity of the adhesive composition is increased and the coating property is increased. Tends to decrease.

The above-mentioned weight average molecular weight is based on standard polystyrene molecular weight conversion. Column: Shodex GPC KF is used in high performance liquid chromatography (manufactured by Waters, Japan, “Waters 2695 (main body)” and “Waters 2414 (detector)”). −806 L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm ) Are used in series.

Examples of the polymer (D) in the present invention include polyethylene resins, polyvinyl chloride resins, polyvinylidene chloride resins, polylactic acid resins, polypropylene resins, polycarbonate resins, polytetrafluoroethylene resins, polyurethane resins. , Polystyrene resin, ABS resin, acrylic resin, polyacetal resin, polyester resin, polyamide resin, polyalkylene oxide resin, and the like. Among these, acrylic resin (D1) ) Is preferably used.
These polymers (D) can be used alone or in combination of two or more.

  The acrylic resin (D1) in the present invention is obtained by polymerizing a monomer component containing a (meth) acrylic monomer.

The acrylic resin (D1) preferably contains, as a main component, a (meth) acrylic acid ester monomer (d1) (except for (d2) described later) as a main component, and if necessary, The functional group-containing monomer (d2) and other copolymerizable monomers (d3) can also be used as a copolymerization component.
Examples of the (meth) acrylic acid ester monomer (d1) include aliphatic (meth) acrylic acid ester monomers such as (meth) acrylic acid alkyl esters, aromatic (meth) acrylic acid ester monomers, and the like. Can be mentioned.
Here, the main component usually means 50% by weight or more of the entire polymerization component.

  Examples of such aliphatic (meth) acrylic acid ester monomers include alkyl (meth) acrylates in which the alkyl group usually has 1 to 12, particularly preferably 1 to 10, and more preferably 1 to 8 carbon atoms. Examples thereof include esters and (meth) acrylic acid esters having an alicyclic structure.

  As such (meth) acrylic acid alkyl ester, specifically, for example, 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 ( Examples include meth) acrylate and stearyl (meth) acrylate.

  Examples of the (meth) acrylic acid ester having such an alicyclic structure include cyclohexyl (meth) acrylate, isobornyl acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentanyloxy. Examples include ethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and 2-adamantyl (meth) acrylate.

  Examples of aromatic (meth) acrylic acid ester monomers include phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyldiethylene glycol (meth) acrylate, and 2-hydroxy-3-phenoxypropyl. (Meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol-polypropylene glycol- (meth) acrylate, nonylphenol ethylene oxide adduct (meth) acrylate, and the like.

Moreover, tetrahydrofurfuryl (meth) acrylate etc. are mentioned as another (meth) acrylic-ester type monomer.
Such a (meth) acrylic acid ester monomer (d1) can be used alone or in combination of two or more.

  Among these (meth) acrylic acid ester monomers (d1), (meth) acrylic acid alkyl esters are preferred in terms of copolymerizability, adhesive properties, ease of handling, and availability of raw materials. (Meth) acrylic groups having 1 to 10 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. Acid alkyl esters are preferably used.

Examples of the functional group-containing monomer (d2) include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an alkoxy group or phenoxy group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, a nitrogen-containing monomer, a glycidyl group-containing monomer, and phosphoric acid. Examples thereof include a group-containing monomer and a sulfonic acid group-containing monomer.
Among these, from the viewpoint of adhesiveness, it is preferable to use a hydroxyl group-containing monomer and a carboxyl group-containing monomer.

Examples of the hydroxyl group-containing monomer include:
2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl ( (Meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate and other (meth) acrylic acid hydroxyalkyl esters, caprolactone-modified 2-hydroxyethyl (meth) acrylate and other caprolactone-modified monomers, 2-acryloyloxy Primary hydroxyl group-containing monomers such as ethyl-2-hydroxyethylphthalic acid, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide;
2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3- Secondary hydroxyl group-containing monomers such as phenoxypropyl (meth) acrylate;
And tertiary hydroxyl group-containing monomers such as 2,2-dimethyl-2-hydroxyethyl (meth) acrylate.
Among these, from the viewpoint of adhesiveness, a primary hydroxyl group-containing monomer is preferable, and 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 5-hydroxypentyl (meth) acrylate are particularly preferable. .

  Further, polyethylene glycol derivatives such as diethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate, polypropylene glycol derivatives such as polypropylene glycol mono (meth) acrylate, polyethylene glycol-polypropylene glycol-mono (meth) acrylate, poly (ethylene Oxyalkylene-modified monomers such as glycol-tetramethylene glycol) mono (meth) acrylate and poly (propylene glycol-tetramethylene glycol) mono (meth) acrylate may be used.

  Examples of the carboxyl group-containing monomer include Michael addition of acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamide N-glycolic acid, cinnamic acid, and (meth) acrylic acid. (Eg, acrylic acid dimer, methacrylic acid dimer, acrylic acid trimer, methacrylic acid trimer, acrylic acid tetramer, methacrylic acid tetramer, etc.), 2- (meth) acryloyloxyethyl dicarboxylic acid monoester (eg, 2-acryloyloxyethyl) Succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxyethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahi Rofutaru acid monoester, 2-methacryloyloxyethyl hexahydrophthalic acid mono ester) and the like. Such a carboxyl group-containing monomer may be used as it is, or may be used in the form of a salt neutralized with an alkali.

  Examples of the alkoxy group-containing monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, and 2-butoxydiethylene glycol. (Meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, octoxypolyethylene glycol- Polypropylene glycol-mono (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate, steer Aliphatic (meth) acrylic acid esters such as xypolyethylene glycol mono (meth) acrylate and the like. Examples of the phenoxy group-containing monomer include 2-phenoxyethyl (meth) acrylate and phenoxypolyethylene glycol (meth) acrylate. And acrylic acid esters of aromatic (meth) acrylates such as phenoxypolyethylene glycol-polypropylene glycol- (meth) acrylate and nonylphenol ethylene oxide adduct (meth) acrylate.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, N- (n-butoxyalkyl) acrylamide, N- (n-butoxyalkyl) methacrylamide, N, N-dimethyl (meth) acrylamide, N, N- Examples include diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, acrylamide-3-methylbutylmethylamine, dimethylaminoalkylacrylamide, and dimethylaminoalkylmethacrylamide.

Examples of the amino group-containing monomer include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and a quaternized product thereof.
Examples of the nitrogen-containing monomer include acryloylmorpholine.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  Examples of the phosphoric acid group-containing monomer include 2- (meth) acryloyloxyethyl acid phosphate, bis (2- (meth) acryloyloxyethyl) acid phosphate, and the like.

  Examples of the sulfonic acid group-containing monomer include olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, styrene sulfonic acid, and salts thereof. .

  Examples of the other copolymerizable monomer (d3) include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, Examples include vinyl pyridine, vinyl pyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, and dimethylallyl vinylketone.

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

  In the acrylic resin (D1), the content ratio of the (meth) acrylic acid ester monomer (d1), the functional group-containing monomer (d2), and the other copolymerizable monomer (d3) in the monomer component is (meth) acrylic. The acid ester monomer (d1) is preferably 50 to 100% by weight, particularly preferably 60 to 95% by weight, and the functional group-containing monomer (d2) is preferably 0 to 50% by weight, particularly preferably 5 to 40% by weight, The other copolymerizable monomer (d3) is preferably 0 to 50% by weight, particularly preferably 5 to 20% by weight.

  In the present invention, the acrylic resin (D1) is produced by polymerizing the monomer components (d1) to (d3). In the polymerization, solution radical polymerization, suspension polymerization, bulk polymerization, It can be performed by a conventionally known method such as emulsion polymerization. For example, in an organic solvent, a polymerization monomer such as the above (meth) acrylic acid ester monomer (d1), functional group-containing monomer (d2), and other copolymerizable monomer (d3), a polymerization initiator (azobisisobutyrate) Ronitrile, azobisisovaleronitrile, benzoyl peroxide, etc.) are mixed or dropped and polymerized at reflux or at 50 to 90 ° C. for 2 to 20 hours.

  As the acrylic resin (D1) in the present invention, a non-functional group-type acrylic resin or a functional group-containing acrylic resin can be used. From the viewpoint of adhesiveness, it is preferable to use a functional group-containing acrylic resin. In particular, it is preferable to use a hydroxyl group-containing acrylic resin or a carboxyl group-containing acrylic resin.

  Examples of the non-functional group-type acrylic resin include acrylic resins obtained by polymerizing the above (d1) and (d3) as monomer components. From the viewpoint of water resistance and adhesiveness, (meth) acrylic ester is used. An acrylic resin obtained by polymerizing a monomer component consisting only of the monomer (d1) is preferred, and in particular, a polymer containing methyl (meth) acrylate and ethyl (meth) acrylate as monomer components is preferred. A polymer having methyl methacrylate and ethyl acrylate as monomer components is preferable, and polyethyl acrylate is particularly preferable.

  Examples of the functional group-containing acrylic resin include an acrylic resin obtained by polymerizing a monomer component containing the functional group-containing monomer (d2), and in particular, a monomer component containing a hydroxyl group-containing monomer. A hydroxyl group-containing acrylic resin and a carboxyl group-containing acrylic resin obtained by polymerizing a monomer component containing a carboxyl group-containing monomer are preferred.

  In the present invention, a solvent-free acrylic resin that does not substantially contain a solvent is used as the acrylic resin (D1). This is preferable in terms of improvement in production efficiency due to omission and improvement in coating property on a material weak against heat and solvent.

As the solventless acrylic resin, an acrylic resin that does not substantially contain a solvent in the resin can be used. As the “acrylic resin substantially free of solvent”, the content of the solvent in the acrylic resin is usually 3% by weight or less, preferably 1% by weight or less, particularly preferably 0.5% by weight or less, more preferably Is an acrylic resin that is 0.2% by weight or less.
Such a solventless acrylic resin generally has a method of polymerizing a polymerizable monomer at a high temperature without using a diluting solvent, or volatilizes the diluting solvent after polymerizing the polymerizable monomer using a diluting solvent. Manufactured with a removing method.

The glass transition temperature (Tg) of the acrylic resin (D1) is usually −100 to 140 ° C., preferably −90 to 110 ° C., particularly preferably −85 to 100 ° C.
If the glass transition temperature is too high, the thermal shrinkage mitigating action of the adhesive tends to decrease, and if too low, the thermal durability of the adhesive tends to decrease or the strength of the adhesive tends to decrease.

The weight average molecular weight of the acrylic resin (D1) is usually 500 to 100,000, preferably 800 to 50,000, particularly preferably 1,000 to 20,000, and particularly preferably 1,200 to 10,000. It is.
If the weight average molecular weight is too large, the strength of the adhesive tends to decrease, and if it is too small, the adhesiveness tends to decrease.

  The method for measuring the weight average molecular weight is the same as that described above, and the glass transition temperature is a value measured using a DSC (differential scanning calorimeter).

Examples of the acrylic resin (D1) include “ARUFON” manufactured by Toagosei Co., Ltd., “JONCRYL” manufactured by BASF, “ARTCURE” manufactured by Negami Kogyo Co., and the like.
“ARUFON UP-1000” (weight average molecular weight: 3,000, glass transition temperature: −77 ° C.), “ARUFON UP-1010” (weight average molecular weight: 1,700, glass transition temperature: −31) manufactured by Toagosei Co., Ltd. ° C), "ARUFON UP-1020" (weight average molecular weight: 2,000, glass transition temperature: -80 ° C), "ARUFON UP-1061" (weight average molecular weight: 1,600, glass transition temperature: -60 ° C) , “ARUFON UP-1080” (weight average molecular weight: 6,000, glass transition temperature: −61 ° C.), “ARUFON UP-1110” (weight average molecular weight: 2,500, glass transition temperature: −64 ° C.), “ "ARUFONUP-1150" (weight average molecular weight: 5,000, glass transition temperature: 68 ° C), "ARUFON UP-1170" (heavy Weight average molecular weight: 8,000, glass transition temperature: −57 ° C., “ARUFON UP-1190” (weight average molecular weight: 1,700, glass transition temperature: −50 ° C.), “ARUFON UP-1500” (weight average) Non-functional group type solvent-free acrylic resin such as molecular weight: 12,000);
“ARUFON UH-2000” (weight average molecular weight: 11,000, glass transition temperature: −55 ° C.), “ARUFON UH-2041” (weight average molecular weight: 2,500, glass transition temperature: −50) manufactured by Toagosei Co., Ltd. ° C.), “ARUFON UH-2170” (weight average molecular weight: 14,000, glass transition temperature: 60 ° C.), “ARUFON UH-2190” (weight average molecular weight: 6,000, glass transition temperature: −47 ° C.), Hydroxyl-containing type solvent-free acrylic resin such as “ARUFON UHE-2012” (weight average molecular weight: 5,800, glass transition temperature: 20 ° C.);
“ARUFON UC-3000” (weight average molecular weight: 10,000, glass transition temperature: 65 ° C.), “ARUFON UC-3080” (weight average molecular weight: 14,000, glass transition temperature: 133 ° C.) manufactured by Toagosei Co., Ltd. , “ARUFON UC-3510” (weight average molecular weight: 2,000, glass transition temperature: −50 ° C.) and the like, a carboxyl group-containing type solvent-free acrylic resin;
Etc.

  The content of the polymer (D) is preferably 2 to 40 parts by weight, particularly 5 to 35 parts by weight, and more preferably 10 to 30 parts by weight with respect to 100 parts by weight of the photopolymerizable compound (A). Preferably there is. If the content of the polymer (D) is too large, the water resistance tends to decrease or the workability tends to decrease due to an increase in viscosity. If the content is too small, the adhesiveness tends to decrease.

  The content ratio of the polymer (D) and the polyfunctional monomer (A2) (polymer / polyfunctional monomer) is preferably 0.03 to 8, more preferably 0.1 to 5, particularly 0 in terms of weight ratio. .15 to 3.5 is preferable. When the content ratio is too small, the adhesive force tends to be reduced, and when it is too large, water resistance is lowered and cracks tend to occur in the thermal shock test.

  Thus, in the present invention, the photopolymerizable compound (A), at least one oxo acid (B) selected from the group 13 metal and metalloid compound, water (C), and polymer (D) are added. The adhesive composition to contain, especially the adhesive composition for polarizing plates can be obtained.

<Polymerization initiator (E)>
Moreover, in this invention, it is preferable to contain a polymerization initiator (E) and to set it as an adhesive composition.
As such a 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.

  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) can be used individually or in combination of 2 or more types.

  Among these photopolymerization initiators (E1), acetophenones and benzoins are preferably used, and in particular, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoin isopropyl ether, 4- (2-hydroxyethoxy) phenyl- It is preferable to use (2-hydroxy-2-propyl) ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one.

  Further, as an auxiliary of the photopolymerization initiator (E1), triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, Ethyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy), isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2, 4-diisopropylthioxanthone or the like can be used in combination.

  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- (hydroxy Methyl) propionitrile] and the like; and the like. These thermal polymerization initiators (E2) can be used alone or in combination of two or more.

  The content of the polymerization initiator (E) is preferably 0.5 to 20 parts by weight, particularly 0.8 to 15 parts by weight with respect to 100 parts by weight of the photopolymerizable compound (A). Furthermore, it is preferable that it is 1-10 weight part. If the content of the polymerization initiator (E) is too small, the curability tends to be poor and the physical properties tend to be unstable. If the content is too large, the low molecular weight component increases, the crosslinking density decreases, and the water resistance and heat resistance decrease. Tend to.

  In preparing the adhesive composition of the present invention, the photopolymerizable compound (A), oxo acid (B), water (C), and polymer (D), preferably further containing a polymerization initiator (E ) In a lump, or after mixing any 2 to 4 components, the remaining components are mixed. Among others, light other than the urethane (meth) acrylate compound (A3) The polymerizable compound (A) and the oxo acid (B) are mixed, heated to 30 to 90 ° C., preferably 40 to 80 ° C., and more preferably 50 to 70 ° C., and stirred to dissolve. ) It is preferable in terms of solubility to mix the acrylate compound (A3), water (C), polymer (D), and polymerization initiator (E). More preferably, among the photopolymerizable compounds (A), the photopolymerizable compound (A1-I) containing a proton accepting group and the oxo acid (B) are first mixed and dissolved as described above, A method of mixing the photopolymerizable compound (A), water (C), polymer (D), and polymerization initiator (E) is preferable from the viewpoint of solubility.

In the adhesive composition of the present invention, in addition to the above components, an antistatic agent, other acrylic adhesives, other adhesives, urethane resin, rosin, rosin ester, as long as the effects of the present invention are not impaired. Hydrogenated rosin ester, phenolic resin, aromatic modified terpene resin, aliphatic petroleum resin, alicyclic petroleum resin, styrene resin, xylene resin and other tackifiers, polyol and other plasticizers, colorant, filling Conventionally known additives such as agents, anti-aging agents, ultraviolet absorbers, functional dyes and the like, and compounds that cause coloration or discoloration upon irradiation with ultraviolet rays or radiation can be blended. 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.

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

  The adhesive composition of the present invention may contain a solvent or may be used as a solvent-free composition, but the solvent-free type that can omit the step of drying the solvent in the adhesive. It is preferable to use it as a composition.

<Polarizer>
There is no restriction | limiting in particular as a polarizer used by this invention, 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 (see, for example, JP-A-2001-296427 and JP-A-7-333426), and (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) Continuously by dehydrating or deaceticating PVA resin or ethylene-vinyl alcohol resin That the polyene structure is introduced, 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.
The moisture content of the polarizer is usually 15% by weight or less, preferably 14% by weight or less, and particularly preferably 0.2 to 13% by weight.

<Protective film>
The protective film used in the present invention can make up for the lack of 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 barrier properties, optical isotropy, and the like.

  As the material for such a protective film, cellulose ester resins, cyclic olefin resins (COP), and (meth) acrylic resins 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 , Polyoxymethylene resins, epoxy resins and the like. These protective films can 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 also other lower fatty acid esters of cellulose, cellulose acetate propionate, cellulose acetate butyrate, etc. The mixed fatty acid ester can be used.

  Examples of the cyclic olefin resin used in the cyclic olefin resin (COP) film include a norbornene resin. Such norbornene resins include, for example, ring-opening (co) polymers of norbornene monomers, addition-polymerized norbornene monomers, and addition-copolymerization of 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. Substitutes 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.

  Commercially available products of cyclic olefin resin (COP) films include “ARTON” manufactured by JSR, “ZEONOR”, “ZEONEX” manufactured by Zeon, “OPTOREZ” manufactured by Hitachi Chemical, “APEL” manufactured by Mitsui Chemicals, etc. Can be mentioned.

  Examples of the (meth) acrylic resin used in the (meth) acrylic resin film include poly (meth) acrylic 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 said protective film is surface hydrophilization of the film which consists of a cellulose ester resin as needed, such as the saponification process by the alkali liquid, the corona discharge process, the plasma treatment, etc. with respect to the film which consists of cyclic olefin resin (COP) It may have been processed.

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 or a titanium coupling agent. In addition, it is also possible to use together said 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 a surface not laminated with a polarizer, or can be subjected to various treatments such as anti-sticking, anti-reflection and anti-glare. Further, various optical functional films such as a retardation plate and a viewing angle widening film can be laminated.

<Polarizing plate>
In the polarizing plate of the present invention, the above polarizer and a protective film are bonded through an adhesive composition for polarizing plate. Specifically, the protective film is bonded to at least one surface, preferably both surfaces of the polarizer, using the polarizing plate adhesive composition of the present invention. After the composition is uniformly applied to the polarizer and / or the protective film, both are bonded together, pressure-bonded, and irradiated with active energy rays to form a polarizing plate.

  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 a 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 without using the said photoinitiator (E1).

A high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, an LED lamp, or the like is used as a light source for 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 (ultraviolet rays, electron beams, 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, and more preferably 0.01 to 1 μm. is there. If the thickness is too thin, the cohesive force of the adhesive force itself cannot be obtained, and the adhesive strength tends to be not obtained. If the thickness is too thick, the workability of the polarizing plate tends to deteriorate due to cracking during punching.

  The adhesive composition of the present invention is an adhesive having excellent adhesive strength at the initial stage and over time, and can be used for various applications, but in particular, for bonding various protective films for polarizing plates and polarizers. It is suitable and shows good adhesiveness without being influenced by the moisture content of the polarizer itself, and further has excellent production efficiency of the polarizing plate without the need for a drying step. It also has excellent resistance to color loss.

  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.

  Prior to the examples and comparative examples, each component of the adhesive composition shown below was prepared.

<Photopolymerizable compound (A)>
<Monofunctional monomer (A1)>
・ (A1-1) Dimethylacrylamide (“DMAA” manufactured by KJ Chemicals)

<Polyfunctional monomer (A2)>
(A2-1) Ethylene oxide modified trimethylolpropane triacrylate (“M-321” manufactured by Toagosei Co., Ltd.)
-(A2-2) Isocyanuric acid ethylene oxide modified triacrylate ("A-9300" manufactured by Shin-Nakamura Chemical Co., Ltd.)

<Urethane (meth) acrylate compound (A3)>
(A3-1) Bifunctional polyether urethane acrylate obtained by Synthesis Example 1 below

[Synthesis Example 1]
A 500 mL reaction vessel equipped with a stirrer was charged with 0.3 g of dibutyltin dilaurate, 0.2 g of 4-methoxyphenol as a polymerization inhibitor, and 166 g of polytetramethylene glycol (molecular weight 650), and these were stirred at the liquid temperature. Was heated to 40 ° C.
200 g of hydrogenated diphenylmethane diisocyanate was gradually added to the reaction solution, and the temperature was raised to 60 ° C. over 1 hour. The reaction was continued until the free NCO% became 8.6% while continuing the reaction at 60 ° C., and then 134 g of 2-hydroxyethyl acrylate was added, and the reaction was continued until the free NCO% became 0.5% or less. A bifunctional polyether urethane acrylate (A3-1) was obtained.
The obtained bifunctional polyether urethane acrylate (A3-1) had a weight average molecular weight of 3,000 and a viscosity of 12,000 mPa · s / 60 ° C.

<Oxo acid (B)>
・ (B-1) Boric acid (Wako Pure Chemical Industries, Ltd.)

<Water (C)>
・ (C-1) Ion exchange water

<Polymer (D)>
-(D-1) Acrylic polymer ("UP-1010" manufactured by Toagosei Co., Ltd.)
(D-2) hydroxyl group-containing acrylic polymer (“UH-2041” manufactured by Toagosei Co., Ltd.)
(D-3) carboxyl group-containing acrylic polymer (“UC-3510” manufactured by Toagosei Co., Ltd.)
・ (D-4) Polyoxypropylene glycol ("SANNICS PP-600" manufactured by Sanyo Chemical Industries)
-(D-5) Polycarbonate diol ("PH50" manufactured by Ube Industries)

<Polymerization initiator (E)>
(E-1) Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (“IRGACURE 819” manufactured by BASF)

[Example 1]
<Preparation of adhesive composition for polarizing plate>
Prepare 75 parts of dimethylacrylamide (A1-1) and 5 parts of boric acid (B-1) at the same time in the preparation flask, and heat them until the liquid temperature reaches 60 ° C while stirring them. Mixing was continued for 1 hour until the acid (B-1) was dissolved. Thereafter, after cooling to room temperature (23 ° C.), 25 parts of ethylene oxide-modified trimethylolpropane triacrylate (A2-1), 8 parts of ion-exchanged water (C-1), 25 parts of acrylic polymer (D-1), 2 parts An adhesive composition for polarizing plates was obtained by simultaneously charging and mixing 25 parts of functional polyether urethane acrylate (A3-1) and 3 parts of Irgacure 819 (E-1).

[Examples 2 to 11, Comparative Examples 1 to 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.

<Production of polarizer>
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. A boric acid treatment was performed for 5 minutes while being uniaxially stretched 3.08 times while being immersed in a boric acid treatment tank (50 ° C.) having a composition of / L. Then, it dried at 90 degreeC and manufactured the polarizer of the total draw ratio 6 times. The moisture content of the polarizer was 1%.

<Preparation of polarizing plate test piece>
Triacetylcellulose (TAC) film (trade name “Fujitack”, manufactured by Fuji Film Co., Ltd.) having a size of 200 mm × 100 mm and thickness of 60 μm, and cyclic olefin resin (COP) film having a size of 200 mm × 100 mm and thickness of 50 μm (Nippon ZEON) The adhesive composition for a polarizing plate obtained above was applied to a product name “ZEONOR”) by a bar coater so as to have a film thickness of 3 μm. Each film with an adhesive composition layer was superposed on both sides of the above polarizer having a size of 180 mm × 80 mm and bonded with a roll machine at a nip pressure of 2 MPa to obtain a laminated film (layer structure of the laminated film: TAC film / polarizer / COP film).
Next, UV irradiation is performed from the COP film side of the laminated film 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 form an adhesive composition. The product was cured to obtain 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 adhesiveness of the TAC film and the polarizer and the COP film and the polarizer when the stress in the 90 ° direction was applied was evaluated according to the following criteria.
(Evaluation criteria)
◎… Particularly firmly bonded ○… Strongly adhered △… Adhered weakly ×… Not adhered

[water resistant]
The polarizing plate test piece was cut into 50 mm × 50 mm, immersed in warm water at 60 ° C., the appearance of the polarizing plate test piece after 24 hours was observed, and evaluated according to the following criteria.
(Evaluation criteria)
○: No peeling from the end of the test piece Δ: There was peeling in a range of less than 5 mm from the end of the test piece x: There was peeling in a range of 5 mm or more from the end of the test piece

[Color loss resistance]
The polarizing plate test piece was cut into 50 mm × 50 mm, immersed in 60 ° C. warm water, the color tone of the polarizing plate test piece after 24 hours was observed, and evaluated according to the following criteria.
(Evaluation criteria)
○: There was no change in color tone with the condition before the test Δ: Slightly lost color (fading) ×: Completely lost color (fading)

In the adhesive compositions of Examples 1 to 11 containing the photopolymerizable compound (A), oxo acid (B), water (C), and polymer (D), the polarizer and the protective film are sufficiently bonded. In addition, it was good in water resistance and color loss resistance, excellent in balance, and suitable for practical use as an adhesive composition for polarizing plates.
On the other hand, in the adhesive compositions of Comparative Examples 1 to 4 that do not contain at least one of oxo acid (B), water (C), and polymer (D), adhesion, water resistance, and color loss resistance Therefore, it was found that the adhesive composition of the present invention is very excellent because it cannot be practically used as an adhesive composition for polarizing plates.

  In the said Example, although the specific form in this invention was shown, the said Example is only a mere illustration and is not interpreted limitedly. Various modifications apparent to those skilled in the art are contemplated to be within the scope of this invention.

  The adhesive composition for polarizing plates comprising the adhesive composition of the present invention and such an adhesive composition is excellent in adhesion between the polarizer and the protective film, and various protective films and polarizers for the polarizing plate. In addition, the polarizing plate is excellent in water resistance and color loss resistance. Furthermore, there is no need for a drying step and the production efficiency is excellent. Moreover, the adhesive composition of the present invention can be used for, for example, bonding various optical films or sheets, bonding electronic parts, precision equipment, packaging materials, display materials, etc. It can also be used.

Claims (8)

  It contains a photopolymerizable compound (A), at least one oxo acid (B) selected from the group 13 metal and metalloid compound, water (C), and polymer (D). An adhesive composition.   The photopolymerizable compound (A) contains an unsaturated compound (A1) having one ethylenically unsaturated group, and the unsaturated compound (A1) having one ethylenically unsaturated group has a proton-accepting group. The adhesive composition according to claim 1, comprising a photopolymerizable compound (A1-I).   The adhesive composition according to claim 1 or 2, wherein the photopolymerizable compound (A) contains an unsaturated compound (A2) having two or more ethylenically unsaturated groups.   The adhesive according to claim 3, wherein the content of the unsaturated compound (A2) having two or more ethylenically unsaturated groups is 5 to 60% by weight in the photopolymerizable compound (A). Composition.   The said photopolymerizable compound (A) contains a urethane (meth) acrylate type compound (A3), The adhesive composition as described in any one of Claims 1-4 characterized by the above-mentioned.   Content of the said polymer (D) is 2-40 weight part with respect to 100 weight part of said photopolymerizable compounds (A), The adhesion | attachment as described in any one of Claims 1-5 characterized by the above-mentioned. Agent composition.   The adhesive composition for polarizing plates using the adhesive composition as described in any one of Claims 1-6.   A polarizer and a protective film are bonded together through the adhesive composition for polarizing plates according to claim 7.