JP2016108564A - Adhesive composition, adhesive composition for polarizing plate, adhesive for polarizing plate and polarizing plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a polarizing plate which is an adhesive excellent in adhesive force, is suitable for bonding various protective films for a polarizing plate with a polarizer, particularly, for bonding a protective film other than TAC with a polarizer and also has excellent production efficiency and excellent resistance to a color void.SOLUTION: There is provided an adhesive composition which comprises a photopolymerizable compound (A) containing a (meth)acrylate consisting of an alkyl group having 6 to 15 carbon atoms or a polyoxyalkylene (meth)acrylate, an oxoacid (B) comprising at least one selected from the group consisting of group 13 metals and semimetal compounds and further preferably water (C).SELECTED DRAWING: None

Description

  The present invention relates to an adhesive composition, an adhesive composition for a polarizing plate, an adhesive for a polarizing plate, and a polarizing plate using the same, and more specifically, a polarizing plate used for a liquid crystal display device or the like. The present invention relates to an adhesive composition suitable for bonding a constituting polarizer and a protective film.

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

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

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

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

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

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

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

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

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

  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 ultraviolet curable adhesive of Patent Document 2 described above, the adhesive layer is relatively hard, resulting in a decrease in adhesive strength over time, which is not satisfactory in terms of punching resistance and durability. There wasn't.
In the radically polymerizable ultraviolet curable adhesive of Patent Document 3 described above, curing shrinkage is accompanied when the (meth) acrylic acid monomer is cured, so that 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.

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

  Furthermore, the adhesive property between the polarizer and the protective film varies depending on the moisture content of the polarizer itself, but it is a polarizing plate that exhibits good adhesion even if the moisture content of the polarizer changes somewhat. There is a need for an adhesive composition. In general, it is considered that the adhesiveness decreases when the moisture content of the polarizer is small. However, even when the moisture content of the polarizer is small, it is required to have good adhesiveness.

  Therefore, in the present invention, under such a background, it is an adhesive having excellent adhesive force, and various protective films for polarizing plates and polarizers, particularly protective films other than TAC such as acrylic films and cyclic polyolefin resin films. In particular, it is suitable for laminating a cyclic polyolefin resin film and a polarizer. Also, it exhibits good adhesiveness regardless of the moisture content of the polarizer itself, has excellent production efficiency, and is also resistant to color loss. It is another object of the present invention to provide an excellent adhesive composition, particularly an adhesive composition for polarizing plates.

  However, as a result of intensive studies in view of such circumstances, the present inventors have found that the photopolymerizable compound (A) is the main component in the adhesive composition, particularly in the active energy ray-curable adhesive composition. It contains at least one oxo acid (B) selected from the group 13 metal or metalloid group, preferably further contains water (C), and is a long-chain photopolymerizable compound. By including a monomer containing an alkyl group or a monomer containing an oxyalkylene chain, the adhesive property between the polarizer and the protective film is excellent, and the color resistance of the polarizing plate is not affected by the moisture content of the polarizer itself. The present invention has been completed by finding out that it is excellent in pull-out property.

  That is, the gist of the present invention is a group of a photopolymerizable compound (A) containing (meth) acrylate (A1) represented by the following general formula (1) or (2) and a group 13 metal or metalloid compound. The present invention relates to an adhesive composition containing at least one oxo acid (B) selected from the above, preferably further containing water (C).

（ここで、Ｒ¹は水素またはメチル基、Ｒ²は炭素数６〜１５のアルキル基である。）
［化２］

（ここで、Ｒ³は水素またはメチル基、Ｒ⁴は炭素数１〜１５のアルキル基、Ｘは炭素数１〜６のアルキレン鎖、ｎは１〜１０の整数である。） [Chemical 1]

(Here, R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 6 to 15 carbon atoms.)
[Chemical 2]

(Here, R ³ is hydrogen or a methyl group, R ⁴ is an alkyl group having 1 to 15 carbon atoms, X is an alkylene chain having 1 to 6 carbon atoms, and n is an integer of 1 to 10)

  Furthermore, this invention also provides the adhesive composition for polarizing plates which uses the said adhesive composition, the adhesive agent for polarizing plates which hardens it, and a polarizing plate.

  Here, in the present invention, in addition to containing an oxo acid (B) composed of at least one selected from the group 13 metal or metalloid compounds, preferably further containing water (C) However, this focuses on the moisture in the polarizer, which has not been noticed so far, and by using water, the water migrates to the surface of the polarizer and makes the polarizer surface layer hydrophilic. Thus, the adhesiveness is further improved.

  In general, when preparing an adhesive composition, if water remains, it is considered that a defect 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, when water is intentionally present, the water content of the polarizer is adjusted, and an unexpected effect that the adhesiveness between the polarizer and the protective film is excellent is found.

  Further, boric acid is preferred for the oxo acid (B) consisting of at least one selected from the group 13 metal or metalloid group, and the photopolymerizable compound (A) is a photopolymerization containing a proton-accepting group. It is preferable that an active compound (A2) is included. This is because, for example, the hydroxyl group in the polarizer and boric acid are cross-linked, and tetrahydroboric acid generated by water chemically bonds with a photopolymerizable compound containing a proton-accepting group. It is also an attempt to improve the sex.

  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, especially the adhesive composition for polarizing plates, has high production efficiency of polarizing plates, and various protective films for polarizing plates and polarizers, particularly acrylic films and cyclic polyolefin resin films. A protective film other than TAC and a polarizer can be sufficiently adhered to each other, and the adhesive film exhibits good adhesiveness regardless of the moisture content of the polarizer. Even in the state immersed in the polarizing plate, it is possible to obtain a polarizing plate excellent in color loss resistance in which color loss is suppressed.

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.
The acrylic monomer is a monomer having at least one of an acryloyl group and a methacryloyl group, and the acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one acrylic monomer.

<Adhesive composition>
The adhesive composition of the present invention comprises a photopolymerizable compound (A) and at least one oxo acid (B) selected from the group of group 13 metals or metalloid compounds, Preferably, water (C) is further contained.

  The photopolymerizable compound (A) used in the present invention is used for coating properties, curability, adhesiveness, and the like. For example, an ethylenically unsaturated compound having one ethylenically unsaturated group ( Hereinafter, it may be described as a monofunctional monomer.) And at least one selected from the group of ethylenically unsaturated compounds having two or more ethylenically unsaturated groups (hereinafter, sometimes referred to as polyfunctional monomers). Preferably it is a seed. Among these, a monofunctional monomer is preferable in terms of coatability.

  Examples of the monofunctional monomer include styrene, vinyl toluene, chlorostyrene, α-methyl styrene, methyl (meth) acrylate, ethyl (meth) acrylate, acrylonitrile, vinyl acetate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxy. Propyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-phenoxy-2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3- Chloro-2-hydroxypropyl (meth) acrylate, glycerin mono (meth) acrylate, glycidyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, isoborni (Meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, n-butyl (meth) acrylate, Hexyl (meth) acrylate, heptyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide modified (n = 2) (meth) acrylate, nonylphenol propylene oxide modified (n = 2.5) (meth) Half (meth) acrylate, furfuryl (meth) acrylate, carbitol (meth) acrylate of phthalic acid derivatives such as acrylate, 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxy-2-hydroxypropyl phthalate , Benzyl (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) acrylate, acryloylmorpholine, dimethylacrylamide, 2-hydroxyethylacrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone, 2-vinylpyridine, And polyoxyethylene secondary alkyl ether acrylate.

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

  In addition, examples of the polyfunctional monomer include a bifunctional monomer and a trifunctional or higher functional monomer.

  Examples of the bifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene. Glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) ) Acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, Xylated cyclohexanedimethanol di (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) Acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, phthalic acid diglycidyl ester di (meth) acrylate, hydroxypivalic acid modified neopentyl glycol di (Meth) acrylate, isocyanuric acid ethylene oxide modified diacrylate and the like.

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

  In the present invention, the photopolymerizable compound (A) includes at least the (meth) acrylate (A1) represented by the general formula (1) or (2) from the viewpoint of exhibiting adhesiveness to the substrate. .

In the above general formula (1), R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 6 to 15, preferably 7 to 12, and more preferably 8 to 10 carbon atoms. If the number of carbon atoms is too small, the adhesiveness to the substrate will be lowered, and if it is too large, the compatibility as the adhesive composition will be lowered and turbidity will be produced.

In the general formula (2), R ³ is hydrogen or a methyl group, R ⁴ is an alkyl group having 1 to 15 carbon atoms, preferably 1 to 12, more preferably 2 to 10 carbon atoms, and X is 1 carbon atom. -6, preferably 2-5, more preferably 2-4 alkylene chains, n is an integer from 1-10, preferably an integer from 1-6. If the alkyl group has too many carbon atoms, the compatibility as the adhesive composition will decrease, and if the alkylene chain has too many carbon atoms, the compatibility as the adhesive composition will decrease. On the other hand, when n is too large, compatibility as a composition is lowered and water resistance is lowered.

  Specific examples of the (meth) acrylate represented by the general formula (1) include, for example, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, and trimethylhexyl (meth) acrylate. , Isononyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, etc., and 2-ethylhexyl (meth) acrylate, n-octyl from the viewpoint of adhesion to the substrate and compatibility as a composition (Meth) acrylate and isooctyl (meth) acrylate are preferably used.

  Specific examples of the (meth) acrylate represented by the general formula (2) include, for example, ethyl carbitol (meth) acrylate, ethylene oxide-modified 2-ethylhexyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, and methoxytriethylene. Examples thereof include glycol (meth) acrylate and methoxydipropylene glycol (meth) acrylate, and ethylcarbitol (meth) acrylate and ethylene oxide-modified 2-ethylhexyl (meth) acrylate are preferably used from the viewpoint of adhesion to the substrate.

  In the present invention, the content (weight ratio) of (meth) acrylate (A1) in the photopolymerizable compound (A) is preferably 3 to 50% by weight, particularly 5 to 40% by weight, and more preferably 7%. It is preferably ˜30% by weight. When the content ratio of the (meth) acrylate (A1) is too low, the adhesive force with the polarizer and the protective film tends to be low, and when it is too high, the compatibility as the composition tends to be low.

  Moreover, in this invention, it is preferable that the photopolymerizable compound (A2) containing a proton-accepting group is included at the point of adhesive force. Furthermore, the photopolymerizable compound (A2) containing a proton-accepting group is preferably a photopolymerizable compound containing a nitrogen atom in terms of compatibility, and in particular, a photopolymerizable compound containing an amide group. It is preferable that it is a compound represented by the following general formula (3).

[Chemical formula 3]
^{_{CH 2 = C (R 1)}} -CONR 2 (R 3) ··· (3)
(In Formula (3), 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 be bonded to each other to contain an oxygen atom or 6 A member ring may be formed, provided that R ² and R ³ are not hydrogen atoms at the same time.)

  Examples of the compound represented by the general formula (3) include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-isopropyl (meth). Acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) Examples include acrylamide, mercaptomethyl (meth) acrylamide, mercaptoethyl (meth) acrylamide, N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Le acrylamide, dialkyl acrylamide such as diethyl acrylamide, cyclic amino acrylates such as N- acryloyl morpholine. Most preferred is dimethylacrylamide.

  In the present invention, the content (weight ratio) of the photopolymerizable compound (A2) in the photopolymerizable compound (A) is preferably 30 to 95% by weight, particularly 40 to 90% by weight, and more preferably 50%. It is preferably ˜80% by weight. When the content ratio of the photopolymerizable compound (A2) is too low, the compatibility as the adhesive composition tends to be lowered, and when it is too high, the adhesiveness to the substrate tends to be lowered.

The oxo acid (B) used in the present invention may be at least one selected from the group consisting of Group 13 metals or metalloid compounds, and is included for imparting an adhesive function. is there.
Examples of the Group 13 metal or metalloid compound include boron, aluminum, gallium, indium, and thallium. Among these, boron is preferable from the viewpoint of solubility in the photopolymerizable compound (A).
As the oxo acid (B), boric acid is particularly preferable from the viewpoint of solubility in the photopolymerizable compound (A).

  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 or metalloid compounds, such as boron. When an acid is used, tetrahydroboric acid produced by boric acid and water (C) is contained for imparting a function of improving adhesiveness.

  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. Further, 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, 0.5 ppm or less as residual chlorine.

  Thus, in the present invention, at least one oxo acid (B) selected from the group of the photopolymerizable compound (A) and the group 13 metal or metalloid compound, preferably water (C) is further contained. The adhesive composition which becomes, especially the adhesive composition for polarizing plates can be obtained.

  In the present invention, the content of the oxo acid (B) comprising at least one selected from the group 13 metal or metalloid compound group is 0.1% with respect to 100 parts by weight of the photopolymerizable compound (A). It is preferably ˜20 parts by weight, in particular 1 to 15 parts by weight, more preferably 2 to 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. .

  The content of the oxo acid (B) is preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the (meth) acrylate (A1) and the photopolymerizable compound (A2). The amount is preferably 1 to 50 parts by weight, more preferably 2 to 20 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. .

  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). It is preferable that it is 1-20 weight part. 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.

  Moreover, it is preferable that content of water (C) is 0.01-80 weight part with respect to 100 weight part of (meth) acrylate (A1) and photopolymerizable compound (A2), and is especially 0. .1 to 50 parts by weight, more preferably 1 to 30 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 not to melt | dissolve with respect to a photopolymerizable compound (A).

  Furthermore, the content ratio (weight ratio) (B / C) of the oxo acid (B) and water (C) consisting of at least one selected from the group 13 metal or metalloid group is 1/9 to It is preferably 8/2, particularly 2/8 to 8/2, more preferably 2.5 / 7.5 to 7.5 / 2.5, especially 3/7 to 7/3. Is preferred. 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.

  Moreover, in this invention, the urethane (meth) acrylate type compound (D) (however, except a photopolymerizable compound (A)) is contained by the point which can make hardening shrinkage of the hardened | cured material small when hardened | cured. Is preferred.

  Such a urethane (meth) acrylate compound (D) is obtained by reacting a hydroxyl group-containing (meth) acrylate compound (d1) and a polyvalent isocyanate compound (d2), or a hydroxyl group-containing (meth) acrylate compound ( Examples include those obtained by reacting d1), a polyvalent isocyanate compound (d2), and a polyol compound (d3). Among these, a urethane (meth) acrylate compound obtained by reacting a hydroxyl group-containing (meth) acrylate compound (d1), a polyvalent isocyanate compound (d2), and a polyol compound (d3) is particularly preferable.

  Examples of the hydroxyl group-containing (meth) acrylate compound (d1) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). ) Acrylate, hydroxyalkyl (meth) acrylate such as 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethyl acryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl ( (Meth) acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono ( 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) An acrylate etc. are mentioned.

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 the compound having two saturated groups, glycerin di (meth) acrylate, and as the 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. In order to increase the cohesive strength of the adhesive composition, it is also preferable to use a polyfunctional (meth) acrylate to the extent that curing shrinkage does not occur.
These hydroxyl group-containing (meth) acrylate compounds can be used alone or in combination.

  Examples of the polyvalent isocyanate compound (d2) include aromatics such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate. Aliphatic polyisocyanates such as polyisocyanates, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1 Examples include alicyclic polyisocyanates such as 3-bis (isocyanatomethyl) cyclohexane, trimer compounds or multimer compounds of these polyisocyanates, allophanate polyisocyanates, burette polyisocyanates, water-dispersed polyisocyanates, and the like. It is done.

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. , Alicyclic diisocyanates such as hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, and more preferably isophorone diisocyanate, water in view of low curing shrinkage. Hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, norbornene diisocyanate are used, and particularly preferred Hydrogenated diphenylmethane diisocyanate in view of excellent reactivity and versatility, hydrogenated xylylene diisocyanate, isophorone diisocyanate is used.
The polyvalent isocyanate compounds can be used alone or in combination of two or more.

  Examples of the polyol compound (d3) 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 kinds of components such as a condensation polymer of polyhydric alcohol and polycarboxylic acid, a ring-opening polymer of cyclic ester (lactone), polyhydric alcohol, polycarboxylic acid and cyclic ester. And 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), and sugar alcohols (such as xylitol and sorbitol).

  Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid, 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-based polyol include a reaction product of a polyhydric alcohol and phosgene, a ring-opening polymer of a cyclic carbonate (such as alkylene carbonate), and the like.

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

  In addition, the polycarbonate 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 saturated hydrocarbon skeleton having a homopolymer or copolymer such as ethylene, propylene and butene, and having a hydroxyl group at the molecular end.

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

  Examples of the (meth) acrylic polyol include those having at least two hydroxyl groups in the molecule of the polymer or copolymer of the (meth) acrylic acid ester. , For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic 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 polyols and polyether polyols are preferable,
In view of the flexibility of the cured product and the compatibility with the photopolymerizable compound (A) and water (C), a polyether-based polyol is particularly preferable, and among them, polytetramethylene glycol is most preferable.

  In the present invention, the polyol compound (d3) preferably has a number average molecular weight of 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 (D) can be produced as follows. The following explanation is about a thing formed by reacting a hydroxyl group-containing (meth) acrylate compound (d1), a polyvalent isocyanate compound (d2) and a polyol compound (d3). By performing, the thing formed by making a hydroxyl-containing (meth) acrylate type compound (d1) and a polyvalent isocyanate type compound (d2) react can also be manufactured.

  For example, (1) A method in which the above-mentioned hydroxyl group-containing (meth) acrylate compound (d1), polyvalent isocyanate compound (d2), and polyol compound (d3) are charged into a reactor or separately and reacted (2) ) A method of reacting a hydroxyl group-containing (meth) acrylate compound (d1) with a reaction product obtained by reacting a polyol compound (d3) with a polyvalent isocyanate compound (d2) in advance; The reaction product obtained by reacting the isocyanate compound (d2) with the hydroxyl group-containing (meth) acrylate compound (d1) in advance may be reacted with the polyol compound (d3). The method (2) is preferred from the standpoint of properties and reduction of by-products.

  For the reaction between the polyol compound (d3) and the polyvalent isocyanate compound (d2), known reaction means can be used. In that case, for example, the molar ratio of the isocyanate group in the polyvalent isocyanate compound (d2) to the hydroxyl group in the polyol compound (d3) is usually about 2n: (2n-2) (n is an integer of 2 or more). By doing this, it is possible to obtain a terminal isocyanate group-containing urethane (meth) acrylate compound having an isocyanate group remaining, and after obtaining the compound, an addition reaction with the hydroxyl group-containing (meth) acrylate compound (d1) is performed. to enable.

  The addition reaction of the reaction product obtained by reacting the polyol compound (d3) and the polyvalent isocyanate compound (d2) in advance with the hydroxyl group-containing (meth) acrylate compound (d1) is also a known reaction. Means can be used.

  The reaction molar ratio between the reaction product and the hydroxyl group-containing (meth) acrylate compound (d1) is, for example, that the polyisocyanate compound (d2) has two isocyanate groups and the hydroxyl group-containing (meth) acrylate compound (d1). ) Has one hydroxyl group, the reaction product: hydroxyl group-containing (meth) acrylate compound (d1) is about 1: 2, and the polyisocyanate compound (d2) has three isocyanate groups. When the hydroxyl group-containing (meth) acrylate compound (d1) has one hydroxyl group, the reaction product: hydroxyl group-containing (meth) acrylate compound (d1) is about 1: 3.

  In the addition reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (d1), the reaction is terminated when the residual isocyanate group content in the reaction system is 0.5% by weight or less. A (meth) acrylate compound (D) is obtained.

  In the reaction between the polyol compound (d3) and the polyvalent isocyanate compound (d2), and further the reaction product and the hydroxyl group-containing (meth) acrylate compound (d1), a catalyst is used for the purpose of promoting the reaction. The catalyst is preferably an organic metal compound such as dibutyltin dilaurate, trimethyltin hydroxide, tetra-n-butyltin, zinc octenoate, tin octenoate, cobalt naphthenate, stannous chloride. Metal salts such as stannic chloride, triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N ′, Amine catalysts such as N'-tetramethyl-1,3-butanediamine and N-ethylmorpholine, bismuth nitrate, bibromide In addition to trout, bismuth iodide, bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, lauryl Organic acid bismuth such as bismuth acid salt, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, bismuth digallate Examples include bismuth-based catalysts such as salts, zirconium-based catalysts such as inorganic zirconium, organic zirconium and zirconium alone, and a combination of two or more catalysts such as zinc 2-ethylhexanoate / zirconium tetraacetylacetonate. , Dibutyltin dilaurate, 1,8-diazabicyclo [5,4,0] undecene is preferred.

  In the reaction between the polyol compound (d3) and the polyvalent isocyanate compound (d2), and further in the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate compound (d1), it reacts with the isocyanate group. An organic solvent having no functional group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatic solvents 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 (D) is obtained.
The weight average molecular weight of the urethane (meth) acrylate compound (D) is preferably 1,000 to 60,000, particularly 1,500 to 50,000, more preferably 2,000 to 30,000. It is preferable. When the weight average molecular weight is too small, the cured shrinkage of the cured product when cured is increased, and the adhesion to the substrate tends to be lowered. When the weight average molecular weight is too large, the viscosity is increased and the 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. product "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 (D) has a viscosity at 60 ° C. of preferably 500 to 100,000 mPa · s, particularly 800 to 50,000 mPa · s, more preferably 1, It is preferable that it is 000-35,000. 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.
In addition, the measuring method of a viscosity is based on an E-type viscometer.

  About content of the said urethane (meth) acrylate type compound (D), it is preferable that it is 3-70 weight part with respect to 100 weight part of photopolymerizable compounds (A), Especially 5-55 weight part, Furthermore, it is preferable that it is 8-40 weight part. If the content is too small, the adhesiveness tends to decrease, and if it is too large, the viscosity is too high and the workability tends to decrease.

In this invention, it is preferable to contain a polymer (E) further at the point which can suppress the cure shrinkage of hardened | cured material.
The polymer (E) used in the present invention is preferably a polymer having no ethylenically unsaturated group. 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 (E), 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.

The polymer (E) in the present invention is, for example, a polyethylene resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, a polylactic acid resin, a polypropylene resin, a polycarbonate resin, a polytetrafluoroethylene resin, or a polyurethane resin. , Polystyrene resin, ABS resin, acrylic resin, polyacetal resin, polyester resin, polyamide resin, polyalkylene oxide resin, and the like. Among these, acrylic resin (E1) from the viewpoint of compatibility and viscosity ) And a polymer (E2) containing a polyoxyalkylene chain are preferably used.
These polymers (E) can be used alone or in combination of two or more.

  The acrylic resin (E1) in the present invention is obtained by polymerizing a monomer component containing a (meth) acrylic monomer.

The acrylic resin (E1) preferably contains a (meth) acrylic acid ester monomer (E1-1) as a main component as a polymerization component, and if necessary, a functional group-containing monomer (E1-2), Another copolymerizable monomer (E1-3) can also be used as a copolymerization component.
Examples of the (meth) acrylic acid ester monomer (E1-1) include, for example, aliphatic (meth) acrylic acid ester monomers such as (meth) acrylic acid alkyl esters, and aromatics such as (meth) acrylic acid phenyl esters. And (meth) acrylic acid ester monomers.

About this (meth) acrylic acid alkyl ester, it is preferable that carbon number of an alkyl group is 1-12 normally, especially 1-8, Furthermore, it is preferable that it is 4-8, Specifically, methyl (meth) acrylate , Ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, n-octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, iso-stearyl (meth) acrylate, cyclohexyl (meth) acrylate , Isobornyl (me ) Acrylate, and the like. Examples of (meth) acrylic acid phenyl ester include benzyl (meth) acrylate and phenoxyethyl (meth) acrylate.
Other (meth) acrylic acid ester monomers include tetrahydrofurfuryl (meth) acrylate and the like.

  Among these (meth) acrylic acid ester monomers (E1-1), methyl (meth) acrylate and n-butyl (meth) acrylate are preferable in terms of copolymerizability, adhesive properties, ease of handling, and availability of raw materials. 2-ethylhexyl (meth) acrylate is preferably used.

  As the functional group-containing monomer (E1-2), for example, 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, Examples thereof include a phosphoric acid group-containing monomer and a sulfonic acid 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, etc. Monomers containing primary hydroxyl groups such as caprolactone-modified monomers, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, etc. 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; tertiary hydroxyl group-containing monomers such as 2,2-dimethyl-2-hydroxyethyl (meth) acrylate.

  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 other copolymerizable monomers (E1-3) include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl. Monomers such as toluene, vinyl pyridine, vinyl pyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethylallyl vinylketone It is done.

  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 (E1), the content ratio of the (meth) acrylic acid ester monomer (E1-1), the functional group-containing monomer (E1-2), and the other copolymerizable monomer (E1-3) is (meta ) Acrylic acid ester monomer (E1-1) is preferably 10 to 100% by weight, particularly preferably 20 to 95% by weight, and functional group-containing monomer (E1-2) is preferably 0 to 90% by weight, particularly preferably. 5 to 80% by weight, and the other copolymerizable monomer (E1-3) is preferably 0 to 50% by weight, particularly preferably 5 to 40% by weight.

  The acrylic resin (E1) in the present invention is preferably a polymer having methyl (meth) acrylate and ethyl (meth) acrylate as polymerization components from the viewpoint of water resistance and adhesiveness, and particularly methyl methacrylate and ethyl. A polymer containing acrylate as a polymerization component is preferable, and polyethyl acrylate is more preferable.

  In the present invention, the acrylic resin (E1) is produced by polymerizing the monomer components (E1-1) to (E1-3). In this polymerization, solution radical polymerization and suspension polymerization are performed. It can be carried out by a conventionally known method such as bulk polymerization or emulsion polymerization. For example, in an organic solvent, a polymerization monomer such as the above (meth) acrylic acid ester monomer (E1-1), a functional group-containing monomer (E1-2), other copolymerizable monomer (E1-3), polymerization start An agent (azobisisobutyronitrile, azobisisovaleronitrile, benzoyl peroxide, etc.) is mixed or dropped and polymerized at reflux or at 50 to 90 ° C. for 2 to 20 hours.

  Further, as the polymer (E2) containing a polyoxyalkylene chain, an allyl glycidyl ether copolymer containing a polyoxyalkylene chain is also preferable, and more preferably an ethylene oxide / propylene oxide / allyl glycidyl ether copolymer. is there.

  The content of the polymer (E) is preferably 2 to 60 parts by weight, particularly 4 to 50 parts by weight, and more preferably 5 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 (E) 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 shrinkage on curing is not relaxed and the adhesiveness tends to decrease. There is.

In the present invention, it is preferable to further contain a polymerization initiator (F) to form an adhesive composition.
As such a polymerization initiator (F), for example, various polymerization initiators such as a photopolymerization initiator (F1) and a thermal polymerization initiator (F2) can be used. The use of F1) is preferable in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  In addition, when the photopolymerization initiator (F1) is used, the adhesive composition is cured by irradiation with active energy rays, and when the thermal polymerization initiator (F2) 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 (F1) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Ben such as ether Ins; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy -3 Thioxanthones such as 4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl- And acyl phosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. In addition, as for these photoinitiators (F1), only 1 type may be used independently and 2 or more types may be used together.

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

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

  Examples of the thermal polymerization initiator (F2) 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-ethylhexanoylperper Oxy) hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t- Hexyl peroxyisopropyl monocarbonate, t-butyl peroxyisobutyrate, -Butyl peroxymalate, t-butyl peroxy-3,5,5-trimethol hexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2- Ethylhexyl monocarbonate, t-butylperoxyacetate, t-butylperoxy-m-toluylbenzoate, t-butylperoxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5- Bis (m-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilyl peroxide , 3,3 ', 4,4'-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'-azo Bisisobutyronitrile, 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] di Doridochloride, 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) propyl Pan] 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-methy] Ru-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropionamide), 2,2'-azobis (2,4,4-trimethylpentane), 2,2'- Azobis (2-methylpropane), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl ) Propionitrile] and the like; and the like. In addition, only 1 type may be used independently for these thermal polymerization initiators, and 2 or more types may be used together.

  The content of the polymerization initiator (F) 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 (F) 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) and oxo acid (B), preferably water (C), urethane (meth) acrylate compound (D), polymer ( E), polymerization initiator (F) may be mixed all at once, or any two to four components may be mixed, and then the remaining components may be mixed. (A) and oxo acid (B) are mixed, heated to 30 to 90 ° C., preferably 40 to 80 ° C., more preferably 50 to 70 ° C., dissolved by stirring, and then water (C), urethane It is preferable in terms of solubility that the (meth) acrylate compound (D), the polymer (E), and the polymerization initiator (F) are mixed. More preferably, among the photopolymerizable compounds (A), when the photopolymerizable compound (A2) is blended, the photopolymerizable compound (A2) and the oxo acid (B) are first mixed and dissolved as described above. After that, the photopolymerizable compound (A1), other photopolymerizable compound (A), water (C), urethane (meth) acrylate compound (D), polymer (E), and polymerization initiator (F) are mixed. 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, colorants, 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 (for example, see JP-A-2001-296427, JP-A-7-333426), (ii) a birefringent material having liquid crystallinity together with a dichroic material in the above (i) is a vinyl alcohol resin What is contained in the film (for example, see JP-A-2007-72203), (iii) A uniaxially stretched thermoplastic norbornene resin film containing a dichroic material (for example, JP-A-2001-356213) (Iv) PVA resin or ethylene-vinyl alcohol resin is dehydrated or deaceticated. Introducing a polyene structure continue, polyene-based film obtained by stretching them (e.g., see JP Patent 2007-17845.), And the like.
Among these, a uniaxially stretched film in which iodine is adsorbed on a PVA-based film is preferable because of excellent polarization characteristics.

The thickness of such a polarizer is usually 0.1 to 100 μm, particularly 0.5 to 80 μm, more preferably 1 to 60 μm.
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 shielding properties, optical isotropy, and the like.

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

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

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

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

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

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

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

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

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

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

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

<Polarizing plate>
The polarizing plate of the present invention is formed by laminating the above polarizer and a protective film via an adhesive for polarizing plates. Specifically, the polarizing plate adhesive composition is usually a liquid polarizing plate, which is formed by laminating a protective film on at least one surface, preferably both surfaces of the polarizer, using the polarizing plate adhesive of the present invention. Is uniformly applied to a polarizer and / or a protective film, and then 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 the range of 0.1 to 10 MPa.

  For such active energy ray irradiation, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X rays and γ rays, electron beams, proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous from the standpoint of availability of the device and price. In addition, when performing electron beam irradiation, it can harden | cure even without using the said photoinitiator (F1).

As a light source for such ultraviolet irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, an LED lamp or the like is used.
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, more preferably 0.01 to 1 μm. It is. If the thickness is too thin, the cohesive force of the adhesive force itself cannot be obtained and the adhesive strength tends not to be obtained. If the thickness is too thick, the workability of the polarizing plate tends to be reduced due to cracks during punching.

  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. In particular, various protective films for polarizing plates and polarizers, particularly those other than TAC. It is suitable for laminating a protective film and a polarizer, and exhibits good adhesion without being influenced by the moisture content of the polarizer itself, and further eliminates the need for a drying step, and also improves the production efficiency of the polarizing plate. It also has excellent resistance to color loss of the polarizing plate.

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

The following components were prepared.
[Photopolymerizable compound (A)]
-(A1-1) 2-ethylhexyl acrylate ("2-ethylhexyl acrylate" manufactured by Mitsubishi Chemical Corporation)
(A1-2) n-octyl acrylate (“NOAA” manufactured by Osaka Organic Chemical Co., Ltd.)
(A1-3) Isooctyl acrylate (“IOAA” manufactured by Osaka Organic Chemical Co., Ltd.)
(A1-4) isononyl acrylate (Osaka Organic Chemical Co., Ltd. “INAA”)
(A1-5) 1,3,3-trimethylhexyl acrylate (A1-6) ethyl carbitol acrylate (Osaka Organic Chemical Co., Ltd. “Biscoat # 190”)
(A1-7) Ethylene oxide modified 2-ethylhexyl acrylate (“Aronix M-120” manufactured by Toa Gosei Co., Ltd.)
(A2-1) Dimethylacrylamide (“DMAA” manufactured by KJ Chemicals)
(A2-2) acryloylmorpholine (“ACMO” manufactured by KJ Chemicals)
・ (A-1) Ethylene glycol diacrylate (“FA-222A” manufactured by Hitachi Chemical Co., Ltd.)
(A-2) Dicyclopentenyl acrylate (“FA-511AS” manufactured by Hitachi Chemical Co., Ltd.)
・ (A-3) Methyl acrylate ("Methyl acrylate" manufactured by Mitsubishi Chemical Corporation)
(A-4) Tertiary butyl acrylate (“TBA” manufactured by Osaka Organic Chemical Co., Ltd.)
(A-5) Isobornyl acrylate (Osaka Organic Chemical Co., Ltd. “IBXA”)

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

[Water (C)]
・ (C-1) Ion exchange water

[Urethane (meth) acrylate compound (D)]
(D-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). 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 (D-1) was obtained.
The obtained bifunctional polyether urethane acrylate (D-1) had a weight average molecular weight of 3,000 and a viscosity of 12,000 mPa · s / 60 ° C.

(D-2) Hexafunctional urethane acrylate obtained by Synthesis Example 2 below [Synthesis Example 2]
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 410 g of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 117). These were heated until the liquid temperature reached 40 ° C. while stirring.
90 g of isophorone diisocyanate was gradually added to the reaction solution, and the temperature was raised to 60 ° C. over 1 hour. While continuing the reaction at 60 ° C., the reaction was continued until the free NCO% became 0.5% or less to obtain hexafunctional urethane acrylate (D-2).
The obtained hexafunctional urethane acrylate (D-2) had a weight average molecular weight of 1,500 and a viscosity of 3,000 mPa · s / 60 ° C.

[Polymer (E)]
-(E1-1) Acrylic polymer ("UP-1010" manufactured by Toagosei Co., Ltd.)

[Photopolymerization initiator (F1)]
(F1-1) 1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by BASF)
(F1-2) 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“IRGACURE TPO” manufactured by BASF)
(F1-3) bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (“Irgacure 819” manufactured by BASF)

[Example 1]
<Preparation of adhesive composition for polarizing plate>
Prepare 51.5 parts of dimethylacrylamide (A2-1) and 3.5 parts of boric acid (B-1) at the same time in a flask for preparation, and heat them until the liquid temperature reaches 60 ° C while stirring them. The mixing was continued for 1 hour until the boric acid (B-1) was completely dissolved. Then, after cooling to room temperature, 15 parts of 2-ethylhexyl acrylate (A1-1), 10 parts of ethylene glycol diacrylate (A-1), 5 parts of ion-exchanged water (C-1), urethane acrylate (D-1) 15 parts, 1.5 parts of Irgacure 184 (F1-1) and 1.5 parts of Irgacure TPO (F1-2) were charged simultaneously and mixed to obtain an adhesive composition for a polarizing plate.

[Examples 2 to 12, Comparative Examples 1 to 7]
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 Tables 1 and 2 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 is stretched 1.3 times while being immersed for 240 seconds in a dyeing tank (30 ° C.) consisting of 0.2 g / L of iodine and 15 g / L of potassium iodide, and further 50 g / L of boric acid and 30 g of potassium iodide. / L was immersed in a boric acid treatment tank (50 ° C.) and boric acid treatment was performed for 5 minutes while simultaneously uniaxially stretching 3.08 times. 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>
After performing a corona discharge treatment on a cycloolefin film having a size of 200 mm × 100 mm and a thickness of 40 μm (trade name “ZEONOR film” manufactured by Nippon Zeon Co., Ltd.), the adhesive composition for polarizing plate obtained above was applied to a bar coater ( No. 10) was applied to a film thickness of 5 μm to prepare a cycloolefin film with an adhesive composition layer.
Also, using an acrylic film having a size of 200 mm × 100 mm and a thickness of 75 μm (trade name “Acryprene” manufactured by Mitsubishi Rayon Co., Ltd.), an adhesive composition for a polarizing plate was applied thereto in the same manner as described above. An acrylic film with a composition layer was prepared.
The obtained cycloolefin film with an adhesive composition layer and an acrylic film with an adhesive composition layer were superimposed on both sides of the above polarizer having a size of 180 mm × 80 mm, and bonded together at a nip pressure of 2 MPa using a roll machine. A laminated film was obtained.
Next, UV irradiation is performed from the cycloolefin film side of the laminated film at a peak illuminance of 130 mW / cm ² and an integrated exposure amount of 900 mJ / cm ² (365 nm) with an ultraviolet irradiation apparatus equipped with a high-pressure mercury lamp. The composition was cured to obtain a polarizing plate test piece.
Performance evaluation was performed as follows using the polarizing plate test piece obtained above. The evaluation results are shown in Tables 1 and 2.

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

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

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

  A photopolymerizable compound (A) containing (meth) acrylate (A1) and at least one oxo acid (B) selected from the group of group 13 metals or metalloid compounds, and further containing water (C) The adhesive compositions for polarizing plates of Examples 1 to 9 are capable of sufficiently bonding a polarizer and a protective film, and also have an excellent effect on water resistance and color loss resistance. On the other hand, the adhesive compositions of Comparative Examples 1 to 6 not containing (meth) acrylate (A1), Comparative Example 2 not containing oxo acid (B), and Comparative Example 3 not containing water (C) Therefore, it is inferior in adhesiveness, water resistance, and color loss resistance, and cannot be practically used as an adhesive composition for polarizing plates, and the adhesive composition of the present invention is very excellent. I understand.

  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 particular, it is suitable for laminating a protective film other than TAC and a polarizer, and exhibits good adhesiveness without being influenced by the moisture content of the polarizer itself. It is also excellent in slipping. In addition, it does not require a drying step and has excellent production efficiency. In particular, it is useful not only for a TAC film but also for bonding a protective film such as an acrylic film or a cyclic polyolefin resin film to a polarizer. . Moreover, the adhesive composition of the present invention can be used for, for example, laminating various optical films or sheets, and laminating electronic parts, precision instruments, packaging materials, display materials, etc. It can also be used.

Claims (17)

It consists of at least 1 sort (s) chosen from the group of the photopolymerizable compound (A) containing the (meth) acrylate (A1) represented by the following general formula (1) or (2), and a group 13 metal or metalloid compound. An adhesive composition comprising an oxo acid (B).
[Chemical 1]

(Here, R ¹ is hydrogen or a methyl group, and R ² is an alkyl group having 6 to 15 carbon atoms.)
[Chemical 2]

(Here, R ³ is hydrogen or a methyl group, R ⁴ is an alkyl group having 1 to 15 carbon atoms, X is an alkylene chain having 1 to 6 carbon atoms, and n is an integer of 1 to 10)   The adhesive composition according to claim 1, comprising water (C).   The adhesive composition according to claim 1 or 2, wherein the photopolymerizable compound (A) comprises a photopolymerizable compound (A2) containing a proton-accepting group. The adhesive composition according to claim 3, wherein the photopolymerizable compound (A2) containing a proton-accepting group is a compound represented by the following general formula (3).
^{_{CH 2 = C (R 1)}} -CONR 2 (R 3) ··· (3)
(In Formula (3), 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 be bonded to each other to contain an oxygen atom or 6 A member ring may be formed, provided that R ² and R ³ are not hydrogen atoms at the same time.)   The adhesive composition according to any one of claims 1 to 4, wherein the oxo acid (B) comprising at least one selected from the group 13 metal or metalloid compound is boric acid.   The content ratio (weight ratio) of the (meth) acrylate (A1) represented by the general formula (1) or (2) in the photopolymerizable compound (A) is 3 to 50% by weight. The adhesive composition according to any one of claims 1 to 5.   The content ratio (weight ratio) of the photopolymerizable compound (A2) containing a proton-accepting group in the photopolymerizable compound (A) is 30 to 95% by weight. The adhesive composition as described.   The content of at least one oxo acid (B) selected from the group 13 metal or metalloid compound group is 0.1 to 20 parts by weight with respect to 100 parts by weight of the photopolymerizable compound (A). The adhesive composition according to any one of claims 1 to 7, wherein   The adhesive composition according to any one of claims 2 to 8, wherein the content of water (C) is 0.01 to 30 parts by weight with respect to 100 parts by weight of the photopolymerizable compound (A). .   The content ratio (B / C) (weight ratio) of at least one oxo acid (B) and water (C) selected from the group 13 metal or metalloid group is 1/9 to 8/2 The adhesive composition according to claim 2, wherein the adhesive composition is present.   The adhesive composition according to any one of claims 1 to 10, comprising a urethane (meth) acrylate compound (D) (excluding the photopolymerizable compound (A)).   The adhesive composition according to claim 1, comprising a polymer (E).   The adhesive composition according to any one of claims 1 to 12, comprising a polymerization initiator (F).   An adhesive composition for polarizing plates, comprising the adhesive composition according to claim 1.   A polarizing plate adhesive obtained by curing the polarizing plate adhesive composition according to claim 14.   An adhesive for polarizing plates, which is obtained by curing the adhesive composition for polarizing plates according to claim 14 by irradiation with active energy rays.   A polarizer and a protective film are bonded to each other through the polarizing plate adhesive according to claim 15 or 16.