JP6922638B2 - Active energy ray-curable adhesive composition, polarizing plate adhesive composition, polarizing plate adhesive, and polarizing plate using the same. - Google Patents

Description

The present invention relates to an active energy ray-curable adhesive composition, a polarizing plate adhesive composition, a polarizing plate adhesive, and a polarizing plate using the same. More specifically, the present invention is used for a liquid crystal display device or the like. The present invention relates to an active energy ray-curable adhesive composition suitable for bonding a polarizing element constituting a polarizing plate 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 a liquid crystal is enclosed, and various optical functional films such as a retardation plate are laminated on the polarizing plates as needed.

Conventionally, the polarizing plate has a configuration in which a protective film is bonded to at least one surface, preferably both surfaces, of a polarizing element made of a polyvinyl alcohol-based film (hereinafter, polyvinyl alcohol is abbreviated as "PVA"). ing. Here, as the polarizer, a dichroic material such as iodine is dispersed and adsorbed in a PVA-based film formed by forming a film using a PVA-based resin having a high degree of saponification, and more preferably, cross-linking of boric acid or the like is performed. A uniaxially stretched PVA-based film crosslinked with an agent is widely used. Since such a polarizer is a uniaxially stretched PVA-based film, it easily shrinks under high humidity. Therefore, a protective film is attached to the polarizer for the purpose of supplementing moisture resistance and strength.

As such a protective film, a thermoplastic resin such as a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, a (meth) acrylic resin, and a polyester resin is transparent, mechanical strength, thermal stability, moisture blocking 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 the adhesive is similar to a PVA-based resin aqueous solution, particularly a polarizer, from the viewpoint of adhesiveness to a polarizer having a hydrophilic surface. A PVA-based resin aqueous solution mainly composed of a PVA-based resin having a high degree of saponification is preferably used.

By the way, in recent years, there has been a demand for thinner polarizing plates, and instead of the triacetyl cellulose (TAC) film, which has been most commonly used as a protective film, an acrylic film or a cyclic olefin resin (COP) has been required. ) Film has come to be used. However, the protective film that replaces these TAC films has problems that it is difficult to firmly bond the protective film to the polarizer with the conventional PVA-based adhesive, and the appearance of the obtained polarizing plate is poor. This is because the acrylic film and the COP film are more hydrophobic than the TAC film, and the water permeability is low, so that the water cannot be sufficiently dried. Therefore, as an alternative to PVA-based adhesives, various adhesives suitable for bonding protective films such as acrylic films and COP films have been developed.

For example, Patent Document 1 specifies aromatic glycidyl ether and an oxetane compound having a specific amount of two or more oxetanyl groups and having a molecular weight of 100 to 800 as an adhesive for a polarizing plate having excellent adhesiveness and water resistance. A silane coupling agent having an alicyclic epoxy group in an amount and a cationically polymerizable adhesive containing a cationic polymerization initiator have been proposed.

Further, in Patent Document 2, a specific oxetane compound having two or more oxetanyl groups and an aromatic glycidyl ether are used as an adhesive capable of maintaining excellent normal adhesive strength for a long period of time regardless of the influence of heat, light, or the like. , And a cationically polymerizable adhesive containing a cationic polymerization initiator has been proposed.

International Publication No. 2012/144261 Japanese Unexamined Patent Publication No. 2010-229392

However, in the above Patent Documents 1 and 2, many epoxy groups having a ring structure such as an alicyclic epoxy group and an aromatic epoxy group are used, and the adhesive itself tends to be too hard, and the usage environment in recent years. Depending on the diversification of the epoxy and the type of protective film to be adhered, sufficient adhesive strength and durability may not be obtained, and further improvement has been required.

Therefore, in the present invention, under such a background, it is an adhesive having excellent adhesive strength, suitable for bonding various protective films for polarizing plates and a polarizer, and also has curability, water resistance, and heat impact. Provided are an active energy ray-curable adhesive composition capable of obtaining an adhesive having excellent durability such as properties, an adhesive composition for a polarizing plate using the same, an adhesive for a polarizing plate, and a polarizing plate. To do.

That is, as a result of diligent research in view of such circumstances, the present inventors have conducted an aliphatic epoxy compound (B) as the epoxy compound (B) together with the oxetane compound (A) in the active energy ray-curable adhesive composition. It contains B1) and an aromatic epoxy compound (B2 ) , and the content ratio of the oxetane compound (A) is 100 parts by weight of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2 ). 75-200 parts by weight der Te is, the content weight ratio of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2) is, (B1) / (B2) = 1 / 1~9 / 1 When der Ru was found that moisture and heat resistance, the adhesive can be formed an adhesive layer having excellent adhesion to balance durability of thermal shock resistance and the like can be obtained.

<Gist of the invention>
The present invention is an active energy ray-curable resin composition containing an oxetane compound (A) and an epoxy compound (B), wherein the epoxy compound (B) is an aliphatic epoxy compound (B1) and an aromatic compound. The content ratio of the epoxy compound (B2 ) and the oxetane compound (A) is 75 to 200 parts by weight with respect to 100 parts by weight of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2 ). Ah is, the content weight ratio of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2) is, (B1) / (B2) = 1 / 1~9 / 1 der Ru active energy ray-curable The first gist is a sex adhesive composition.

Further, the second gist of the present invention is an adhesive composition for a polarizing plate, which comprises the above-mentioned active energy ray-curable adhesive composition. The third gist is an adhesive for a polarizing plate, which is a cured product of the adhesive composition for a polarizing plate. The fourth gist is a polarizing plate in which a polarizing element and a protective film are bonded to each other via the above-mentioned adhesive for a polarizing plate.

The present invention contains an oxetane compound (A) and an epoxy compound (B), and the epoxy compound (B) contains an aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2 ) , and oxetane. content of the compound (a), aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2) 1 00 Ri 75-200 parts by der relative parts by weight, the aliphatic epoxy compound (B1 ) and the content weight ratio of the aromatic epoxy compound (B2) is a (B1) / (B2) = 1 / 1~9 / 1 der Ru active energy ray-curable adhesive composition. Therefore, various protective films for polarizing plates and a polarizer can be sufficiently adhered to each other, and a polarizing plate having excellent durability such as moisture heat resistance and heat impact resistance can be obtained.

When the content ratio of the oxetane compound (A) is 30% by weight or more with respect to the total amount of the oxetane compound (A) and the epoxy compound (B), the curability and adhesiveness are further improved.

The epoxy compound (B) contains an aliphatic epoxy compound (B1), and the content ratio of the aliphatic epoxy compound (B1) is relative to the total amount of the oxetan compound (A) and the epoxy compound (B). When it is 5 to 60% by weight, the adhesiveness is further improved.

The epoxy compound (B) contains an aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2), and also contains the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2). weight ratio, and (B1) / (B2) When it is = 1 / 1-9 / 1, that is further improved adhesion and durability.

Further, when the unsaturated compound (C) having at least one ethylenically unsaturated group is contained in the molecule, the curability is further improved.

When the content of the unsaturated compound (C) having an ethylenically unsaturated group is 2 to 100 parts by weight with respect to 100 parts by weight of the total amount of the oxetane compound (A) and the epoxy compound (B), the curability is determined. Adhesiveness and durability are further improved.

Further, when the silane coupling agent (D) is contained, the adhesiveness is further improved.

When the content of the silane coupling agent (D) is 2 to 50 parts by weight with respect to a total of 100 parts by weight of the oxetane compound (A) and the epoxy compound (B), the adhesiveness and durability are further improved. In addition, liquid stability is improved.

Alternatively, the content of the silane coupling agent (D) is 2 to 2 to 100 parts by weight in total of the oxetane compound (A), the epoxy compound (B) and the unsaturated compound (C) having an ethylenically unsaturated group. When it is 50 parts by weight, the liquid stability is improved in addition to the further improvement of the adhesiveness and durability.

Hereinafter, the present invention will be described in detail, and these are examples of desirable embodiments.

The active energy ray-curable adhesive composition of the present invention (hereinafter, may be abbreviated as "adhesive composition") includes an oxetane compound (A), an aliphatic epoxy compound (B1), and an aromatic epoxy. It contains an epoxy compound (B) containing a compound (B2 ). Hereinafter, each component of the adhesive composition will be described in order.

In the present invention, (meth) acrylic means acrylic or methacrylic, (meth) acryloyl means acryloyl or methacrylic, and (meth) acrylate means acrylate or methacrylate.

<Oxetane compound (A)>
The oxetane compound (A) used in the present invention may be a compound having one or more oxetanyl groups in the molecule.
Examples of the oxetane compound (A) include 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, and 3-. One oxetane group is contained in a molecule such as ethyl-3- (cyclohexyloxymethyl) oxetane, 3-ethyl-3- (oxylanylmethoxy) oxetane, and (meth) acrylic acid (3-ethyloxetane-3-yl) methyl. Oxetane compounds, 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, 4 , 4'-Bis [(3-ethyl-3-oxetanyl) methoxymethyl] Biphenyl and other oxetane compounds having two or more oxetane groups in the molecule, and the like. These oxetane compounds (A) can be used alone or in combination of two or more.

Among them, 3-ethyl-3-hydroxymethyloxetane and 1,4-bis [(3-ethyl-3-oxetanyl) are easy to obtain, dilute (low viscosity), and have excellent compatibility. ) Methylmethyl] benzene, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3- (oxylanylmethoxy) oxetane, (meth) acrylic acid (3-ethyloxetane-3-yl) Methyl, 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane and the like are preferably used.

Further, from the viewpoint of coatability and adhesiveness, a liquid having a molecular weight of 500 or less at room temperature (25 ° C.) is preferable, and from the viewpoint of excellent curability and durability, two or more oxetane group groups are contained in the molecule. Oxetane compounds contained or oxetane compounds containing one oxetaneyl group and one (meth) acryloyl group or one epoxy group in the molecule are preferable, and in particular, 3-ethyl-3 {[(3-ethyl). Oxetane-3-yl) methoxy] methyl} oxetane, 3-ethyl-3- (oxylanylmethoxy) oxetane, and (meth) acrylic acid (3-ethyloxetane-3-yl) methyl are preferably used.

Specific examples of the oxetane compound (A) include commercially available products such as Aron Oxetane OXT-101, Aron Oxetane OXT-121, Aron Oxetane OXT-111, Aron Oxetane OXT-212, Aron Oxetane OXT-213, and Aron. Oxetane OXT-221 (both manufactured by Toagosei Co., Ltd.) can be used. In particular, Aron Oxetane OXT-101 and Aron Oxetane OXT-221 are preferable.

The content ratio of the oxetane compound (A) needs to be 75 to 200 parts by weight with respect to 100 parts by weight of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2 ) described later. preferably 75 to 180 parts by weight, especially, more preferably from 75 to 150 parts by weight. If the content ratio is too small, the curability and adhesiveness are lowered, and if the content ratio is too large, the adhesiveness is lowered, so that the object of the present invention cannot be achieved.

The content ratio of the oxetane compound (A) is preferably 30% by weight or more, more preferably 35 to 70% by weight, and particularly preferably 35% by weight, based on the total amount of the oxetane compound (A) and the epoxy compound (B). Is 40-65% by weight. If the content of the oxetane compound (A) is too small, the curability tends to be insufficient, and if it is too large, the adhesive strength tends to decrease.

<Epoxy compound (B)>
The epoxy compound (B) contains an aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2 ) .

Examples of the aliphatic epoxy compound (B1) include butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, glycidol, alcohol glycidyl ether having 11 to 15 carbon atoms, and lauryl alcohol glycidyl ether. An aliphatic epoxy compound having one group, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl Ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, polybutadiene diglycidyl ether, sorbitol polyglycidyl ether, glycerin polyglycidyl ether, poly Examples thereof include bifunctional or higher aliphatic epoxy compounds having two or more epoxy groups in the molecule such as glycerin polyglycidyl ether. These aliphatic epoxy compounds can be used alone or in combination of two or more.

Examples of the aromatic epoxy compound (B2) include phenylglycidyl ether, p-tert-butylphenylglycidyl ether, p-sec-butylphenylglycidyl ether, dibromophenylglycidyl ether, resorcin diglycidyl ether and the like in the molecule. Aromatic epoxy compounds having one epoxy group, phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, hydroquinone diglycidyl ether, bromobisphenol A diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol Examples thereof include aromatic epoxy compounds having two or more epoxy groups in the molecule, such as E-type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, novolac type epoxy resin, and biphenyl type epoxy resin. Of these, aromatic epoxy compounds having two or more epoxy groups in the molecule are preferable from the viewpoint of adhesiveness and durability, and bisphenol A type epoxy resin and bisphenol F type epoxy resin are particularly used from the viewpoint of excellent curability. Is preferable. These aromatic epoxy compounds can be used alone or in combination of two or more.

In the present invention, it is preferable to contain at least an aliphatic epoxy compound (B1) as the epoxy compound (B) from the viewpoint of adhesiveness and durability, and particularly in the molecule from the viewpoint of curability and durability. A bifunctional or higher aliphatic epoxy compound having two or more epoxy groups is preferable, and 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and neopentyl are excellent in terms of adhesiveness. It is preferable to use glycol diglycidyl ether.

The content of the aliphatic epoxy compound (B1) is preferably 5 to 60% by weight, more preferably 10 to 55% by weight, based on the total amount of the oxetane compound (A) and the epoxy compound (B). It is particularly preferably 15 to 50% by weight. If the content of the aliphatic epoxy compound (B1) is too small, the adhesiveness tends to decrease, and if it is too large, the durability tends to decrease.

Further, from the viewpoint of durability (particularly heat impact resistance), it is preferable to contain an aromatic epoxy compound (B2) as the epoxy compound (B), and particularly from the viewpoint of curability and durability, it is intramolecular. An aromatic epoxy compound having two or more epoxy groups is preferable, and a bisphenol A type epoxy resin and a bisphenol F type epoxy resin are preferably used from the viewpoint of excellent adhesiveness.

The content of the aromatic epoxy compound (B2) is preferably 5 to 60% by weight, more preferably 5 to 55% by weight, based on the total amount of the oxetane compound (A) and the epoxy compound (B). %, Especially preferably 10 to 50% by weight. If the content of the aromatic epoxy compound (B2) is too small, the durability tends to decrease, and if it is too large, the adhesiveness tends to decrease.

Furthermore, from the viewpoint of excellent well-balanced in various physical properties, you combination of an aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2) as the epoxy compound (B).
When the epoxy compound (B) contains an aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2) [combination system of (B1) and (B2)], the aliphatic epoxy compound (B1) and the content weight ratio of the aromatic epoxy compound (B2) is, (B1) / (B2) = 1/1 ~9 / 1 der is, particularly preferably (B1) / (B2) = 1/1 ~ 8.5 / 1.5, more preferably (B1) / (B2) = 1/1 ~4 / 1, particularly preferably from (B1) / (B2) = 1 / 1~3 / 1.
If the content weight ratio is too small (the amount of the aromatic epoxy compound (B2) is too large), the adhesive strength tends to decrease or the compatibility of the adhesive composition tends to decrease, and the content weight ratio is too large (the content weight ratio tends to decrease). Too much aliphatic epoxy compound (B1)) tends to reduce durability. Further, from the viewpoint of the balance between adhesiveness and durability, it is preferable that the difference in the contents of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2) is small, and further, the aliphatic epoxy compound. It is more preferable that the difference in content between (B1) and the aromatic epoxy compound (B2) is small, and that the aliphatic epoxy compound (B1) is contained in the same amount or more with respect to the aromatic epoxy compound (B2). ..

Further, the epoxy compound (B) of the present invention may contain other epoxy compounds (B3) in addition to the above-mentioned aliphatic epoxy compound (B1) and aromatic epoxy compound (B2).

Examples of the other epoxy compound (B3) include a triazine skeleton-containing epoxy compound, an alicyclic epoxy compound, and an alicyclic skeleton-containing epoxy compound. These can be used alone or in combination of two or more.

The triazine skeleton-containing epoxy compound contains one or more epoxy groups and a triazine skeleton in the molecule, and is, for example, tris (2,3-epoxypropyl) -isocyanurate, tris (3,4-epoxybutyl). )-Isocyanurate, Tris (4,5-epoxypentyl) -Isocyanurate, Tris- (5,6-epoxyhexyl) -Isocyanurate, Tris (6,7-epoxyheptyl) -Isocyanurate, Tris (7,8) -Epoxy octyl) -isocyanurate and the like. These can be used alone or in combination of two or more.
From the viewpoint of further improving durability (heat impact resistance), it is also preferable to use a triazine skeleton-containing epoxy compound.

The triazine skeleton-containing epoxy compound preferably has an epoxy equivalent of 120 g / eq or more, particularly preferably 120 to 300 g / eq, and even more preferably 120 to 250 g / eq, from the viewpoint of adhesiveness and durability.

Specific examples of the triazine skeleton-containing epoxy compound include commercially available TEPIC series (TEPIC-G, TEPIC-S, TEPIC-SS, TEPIC-HP, TEPIC-L, TEPIC-" manufactured by Nissan Chemical Industries, Ltd. PAS, TEPIC-VL, TEPIC-UC, TEPIC-FL, etc.) and the like can be used. Of these, liquid epoxy compounds TEPIC-PAS, TEPIC-VL, TEPIC-UC, and TEPIC-FL are preferable from the viewpoint of compatibility.

Examples of the alicyclic epoxy compound include dicyclopentadiene oxide, limonendioxide, 4-vinylcyclohexendioxide, 3', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and ε-caprolactone modification. Examples thereof include 3', 4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and bis (3,4-epoxycyclohexylmethyl) adipate. These can be used alone or in combination of two or more.
Specifically, as the alicyclic epoxy compound, for example, commercially available products such as "Selokiside 2021P" and "Seloxiside 2000" manufactured by Daicel Corporation can be used.

Examples of the alicyclic skeleton-containing epoxy compound include an epoxy compound in which an aromatic ring is hydrogenated, such as hydrogenated bisphenol A diglycidyl ether, and cyclohexanedimethanol diglycidyl ether. These can be used alone or in combination of two or more.
Specifically, as the alicyclic skeleton-containing epoxy compound, for example, a commercially available product "Denacol EX-216L" manufactured by Nagase ChemteX Corporation can be used.

The content of at least one of the alicyclic epoxy compound and the alicyclic skeleton-containing epoxy compound is preferably 30% by weight or less based on the total amount of the oxetane compound (A) and the epoxy compound (B), and more preferably. It is 20% by weight or less, particularly preferably 15% by weight or less. If the content of at least one of the alicyclic epoxy compound and the alicyclic skeleton-containing epoxy compound is too large, the adhesive strength tends to decrease.

The content of the other epoxy compound (B3) is preferably 30% by weight or less, more preferably 20% by weight or less, and particularly preferably 10% by weight or less, based on the entire epoxy compound (B). If the content of the other epoxy compound (B3) is too large, the adhesive strength tends to decrease.

In the present invention, the epoxy compound (B), as described above, those containing aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2). Further, the other epoxy compound (B3) may be contained, but it is preferably 30% by weight or less, more preferably 20% by weight or less, still more preferably 10% by weight or less of the whole epoxy compound (B).

<Unsaturated compound (C) having an ethylenically unsaturated group>
In the present invention, in addition to the above components, an unsaturated compound having at least one ethylenically unsaturated group in the molecule as a radical polymerization component (hereinafter, may be abbreviated as "ethylenically unsaturated compound"). (C) can be used. By using the ethylenically unsaturated compound (C), the curing rate can be adjusted and the curability can be improved. When the ethylenically unsaturated compound (C) is used as a radical polymerization component, it is preferable to use a photoradical polymerization initiator described later.

Examples of the ethylenically unsaturated compound (C) include (meth) acrylic compounds having at least one (meth) acryloyl group in the molecule.

The (meth) acrylic compound may be described as, for example, a (meth) acrylic compound having one (meth) acryloyl group in the molecule (hereinafter, referred to as “monofunctional (meth) acrylic compound”. ), (Meta) acrylic compounds having two or more (meth) acryloyl groups in the molecule (hereinafter, may be referred to as "polyfunctional (meth) acrylic compounds").
These (meth) acrylic compounds can be used alone or in combination of two or more.

Examples of the monofunctional (meth) acrylic compound include an alkyl (meth) acrylate compound, a polar group-containing (meth) acrylic compound, an alicyclic (meth) acrylate compound, and an aromatic (meth) acrylate compound. Examples thereof include (meth) acrylic compounds having a reactive functional group other than the (meth) acryloyl group and the (meth) acryloyl group in the molecule.

Examples of the alkyl (meth) acrylate-based compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and the like can be mentioned.

Examples of the polar group-containing (meth) acrylic compound include a carboxyl group-containing (meth) acrylic compound, a hydroxyl group-containing (meth) acrylic compound, a nitrogen atom-containing (meth) acrylic compound, and an alkoxy group-containing (meth) compound. Acrylic compounds and the like can be mentioned.

Examples of the carboxyl group-containing (meth) acrylic compound include (meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, phthalic acid, acrylamide N-glycolic acid, silicic acid, and (meth). Michael adducts of acrylic acid (eg, acrylic acid dimer, methacrylic acid dimer, acrylate trimmer, methacrylic acid trimmer, phthalate tetramer, tetramer methacrylate, etc.), 2- (meth) acryloyloxyethyl dicarboxylic acid monoester (eg, eg) 2-Acryloyloxyethyl succinic acid monoester, 2-methacryloyloxyethyl succinic acid monoester, 2-acryloyloxyethyl phthalic acid monoester, 2-methacryloyloxyethyl phthalic acid monoester, 2-acryloyloxyethyl hexahydrophthalic acid monoester Esters, 2-methacryloyloxyethyl hexahydrophthalic acid monoesters, etc.) and the like.

Examples of the hydroxyl group-containing (meth) acrylic compound include 2-hydroxyethyl (meth) acrylicate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, and 6-hydroxyhexyl (meth). Hydroxyalkyl (meth) acrylate-based compounds such as acrylate,
Caprolactone-modified (meth) acrylate-based compounds such as caprolactone-modified 2-hydroxyethyl (meth) acrylate, ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, pentanediol mono (meth) acrylate, and hexanediol mono ( Mono (meth) acrylate-based compounds of dihydric alcohols such as meta) acrylates,
Diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, tripropylene glycol Mono (meth) acrylate and polyalkylene glycol mono (meth) acrylate compounds such as polypropylene glycol mono (meth) acrylate,
In addition, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid,
Etc., primary hydroxyl group-containing (meth) acrylate compounds;
Secondary hydroxyl group-containing (meth) acrylate compounds such as 2-hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate;
Tertiary hydroxyl group (meth) acrylate compounds such as 2,2-dimethyl2-hydroxyethyl (meth) acrylate;
And so on.
Among such hydroxyl group-containing (meth) acrylic compounds, primary hydroxyl group-containing (meth) acrylate-based compounds are preferable, and hydroxyalkyl (meth) acrylate-based compounds are particularly preferable because they are likely to form hydrogen bonds with a base material or a polarizer and have excellent reactivity. Meta) acrylate compounds and mono (meth) acrylate compounds of polyalkylene glycol are preferable.

Examples of the nitrogen atom-containing (meth) acrylic compound include an amide group-containing (meth) acrylic compound, an amino group-containing (meth) acrylic compound, and other nitrogen atom-containing (meth) acrylic compounds.
Examples of the amide group-containing (meth) acrylic compound include, for example.
(Meta) acrylamide;
N, N-dialkyl (meth) acrylamide such as N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide;
N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide, N-n-butoxymethyl (meth) acrylamide, N- N-alkoxyalkyl (meth) acrylamide such as isobutoxymethyl (meth) acrylamide;
Hydroxy-containing acrylamide such as N- (hydroxymethyl) (meth) acrylamide;
Examples thereof include N- (3-N, N-dimethylaminopropyl) (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide and the like.
Examples of the amino group-containing (meth) acrylic compound include, for example, aminomethyl (meth) acrylate, aminoethyl (meth) acrylate and the like, primary amino group-containing (meth) acrylate such as aminoalkyl (meth) acrylate, and t-butyl. Secondary amino group-containing (meth) acrylate such as aminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, etc., dialkylaminoalkyl (meth) acrylate, etc. Examples thereof include heterocyclic amine monomers such as tertiary amino group-containing (meth) acrylate and acryloyl morpholine.

Examples of the alkoxy group-containing acrylic compound include
Alkoxyalkyl (meth) acrylate-based compounds such as 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, and 2-butoxyethyl (meth) acrylate,
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, Octo Examples thereof include polyether chain-containing (meth) acrylate compounds such as xypolyethylene glycol-polypropylene glycol-mono (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate, and stearoxypolyethylene glycol mono (meth) acrylate.

Examples of the alicyclic (meth) acrylate compound include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 1,4-cyclohexanedimethylol mono (meth) acrylate, dicyclopentanyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. Cyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-adamantyl (meth) acrylate and the like can be mentioned.

Examples of the aromatic (meth) acrylate compound include phenyl (meth) acrylate;
Benzyl (meth) acrylate;
Phenoxyalkyl (meth) acrylates such as phenoxyethyl (meth) acrylate and phenoxypropyl (meth) acrylate;
Phenoxydialkylene glycol (meth) acrylates such as phenoxydiethylene glycol (meth) acrylates and phenoxydipropylene glycol (meth) acrylates;
Phenoxy polyethylene glycol (meth) acrylate;
Phenoxy Polyethylene Glycol-Polypropylene Glycol- (Meta) Acrylate;
(Meta) acrylate of p-cumylphenol alkylene oxide adduct, (meth) acrylate of o-phenylphenol alkylene oxide adduct, (meth) acrylate of phenol alkylene oxide adduct and (meth) acrylate of nonylphenol alkylene oxide adduct And so on.

Examples of the (meth) acrylic compound having a reactive functional group other than the (meth) acryloyl group and the (meth) acryloyl group in the molecule include, for example.
Epoxy group-containing (meth) acrylate compounds such as glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth) acrylate,
Vinyl group-containing (meth) acrylate compounds such as 2- (2-vinyloxyethoxy) ethyl (meth) acrylate,
Examples thereof include isocyanate group-containing (meth) acrylate compounds such as 2- (meth) acryloyloxyethyl isocyanate.

In addition, (meth) acrylate compounds having a cyclic ether structure such as tetrahydrofurfuryl (meth) acrylate and caprolactone-modified tetrahydrofurfuryl (meth) acrylate can also be mentioned.

In addition, examples of the polyfunctional (meth) acrylic compound include bifunctional (meth) acrylic compounds and trifunctional or higher functional (meth) acrylic compounds.

Examples of the bifunctional (meth) acrylic compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol di. (Meta) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate , 1,4-Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerindi (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate , Diethylene glycol diglycidyl ether di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, etc. Di (meth) acrylate having a long chain or branched chain structure;
Di (meth) acrylate with cyclohexanedimethanol di (meth) acrylate, dimethyloldicyclopentane di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, ethylene oxide-modified cyclohexanedimethanol di (meth) acrylate, etc. (Meta) acrylate;
Ethyleneoxide-modified bisphenol A-type di (meth) acrylate, alkylene oxide-modified bisphenol A-type di (meth) acrylate such as propylene oxide-modified bisphenol A-type di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, phthalic acid Diglycidyl ester Di (meth) acrylate having an aromatic ring such as di (meth) acrylate;
Di (meth) acrylate having a ring structure such as isocyanuric acid ethylene oxide-modified di (meth) acrylate;
And so on.

Examples of the trifunctional or higher functional (meth) acrylic compound include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol penta (meth) acrylate. Dipentaerythritol hexa (meth) acrylate, polyglycerin poly (meth) acrylate;
Caprolactone-modified dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, ethylene oxide-modified dipentaerythritol penta ( Alkyl such as meta) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tetra (meth) acrylate, and ethylene oxide-modified glycerin tri (meth) acrylate. A trifunctional or higher functional (meth) acrylate having a modified structure, or the like, a trifunctional or higher functional (meth) acrylate having a long chain or branched chain structure;
Tri (meth) acrylate having a ring structure such as isocyanuric acid ethylene oxide-modified triacrylate;
And so on.

Oligomers such as urethane (meth) acrylate, polyester (meth) acrylate and epoxy (meth) acrylate can also be used as the (meth) acrylic compound.

As the ethylenically unsaturated compound (C), it is preferable to use a bifunctional or higher functional (meth) acrylic compound from the viewpoint of improving the curability of the adhesive composition and increasing the durability. In particular, a bifunctional or higher functional (meth) acrylic compound having an alicyclic or aromatic ring, or a (meth) acrylic compound having a linear or branched chain structure having no polyalkylene oxide skeleton is preferable.

The content of the ethylenically unsaturated compound (C) is preferably 2 to 100 parts by weight, more preferably 5 to 100 parts by weight, based on 100 parts by weight of the total of the oxetane compound (A) and the epoxy compound (B). It is 50 parts by weight, more preferably 10 to 30 parts by weight. If the content of the ethylenically unsaturated compound (C) is too large, the curing shrinkage tends to be large and the adhesive strength tends to decrease. Further, if the content of the ethylenically unsaturated compound (C) is too small, the curing rate tends to decrease.

<Silane coupling agent (D)>
The adhesive composition of the present invention preferably further contains a silane coupling agent (D) from the viewpoint of improving adhesiveness.

The silane coupling agent (D) is usually an organosilicon compound containing at least one reactive functional group and one or more silicon atom-bonded alkoxy groups in the structure, and improves the adhesiveness between the adhesive layer and the protective film. Can be made to.

Examples of the silane coupling agent (D) include an epoxy group-containing silane coupling agent, a mercapto group-containing silane coupling agent, a (meth) acryloyl group-containing silane coupling agent, an amino group-containing silane coupling agent, and an isocyanate group. Examples thereof include a containing silane coupling agent, a vinyl group-containing silane coupling agent, a hydroxyl group-containing silane coupling agent, a carboxyl group-containing silane coupling agent, and an amide group-containing silane coupling agent. These can be used alone or in combination of two or more.

Examples of the epoxy group-containing silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyl. Monomer type such as glycidyloxy group (aliphatic epoxy group) -containing silane coupling agent such as methyldimethoxysilane, alicyclic epoxy group-containing silane coupling agent such as 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, etc. Epoxy group-containing silane coupling agent and a part of the above silane compound are hydrolyzed and polymerized, or the above silane compound and an alkyl such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane. Examples thereof include an oligomer-type silane coupling agent in which a group-containing silane compound is co-condensed. These can be used alone or in combination of two or more.

Examples of the mercapto group-containing silane coupling agent include monomer-type mercaptos such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane, and 3-mercaptopropylmethyldimethoxysilane. A group-containing silane coupling agent or a part of the above silane compound is hydrolyzed and polymerized, or the above silane compound contains an alkyl group such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, or ethyltrimethoxysilane. Examples thereof include an oligomer-type silane coupling agent in which a silane compound is co-condensed. These can be used alone or in combination of two or more.

Examples of the (meth) acryloyl group-containing silane coupling agent include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltri. Examples thereof include ethoxysilane and 3-acryloxypropyltrimethoxysilane. These can be used alone or in combination of two or more.

Examples of the amino group-containing silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and 3-amino. Examples thereof include propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, and N-phenyl-3-aminopropyltrimethoxysilane. These can be used alone or in combination of two or more.

Examples of the isocyanate group-containing silane coupling agent include 3-isocyanatepropyltriethoxysilane. These can be used alone or in combination of two or more.

Examples of the vinyl group-containing silane coupling agent include vinyltrimethoxysilane and vinyltriethoxysilane. These can be used alone or in combination of two or more.

Among the above silane coupling agents (D), epoxy group-containing silanes are excellent in reactivity with curable components (oxetan compound (A), epoxy compound (B), and ethylenically unsaturated compound (C)). It is preferable to use a coupling agent, a vinyl group-containing silane coupling agent, and a (meth) acryloyl group-containing silane coupling agent, and particularly preferably an epoxy group-containing silane coupling agent and a (meth) acryloyl group-containing silane coupling agent. be. The silane coupling agent (D) may be a monomer-type silane coupling agent or an oligomer-type silane coupling agent that is partially hydrolyzed and polycondensed, but from the viewpoint of compatibility and adhesiveness, it may be used. It is preferable to use a monomer-type silane coupling agent.

The content of the silane coupling agent (D) is preferably 2 to 50 parts by weight, particularly preferably 3 to 40 parts by weight, based on 100 parts by weight of the total of the oxetane compound (A) and the epoxy compound (B). It is by weight, more preferably 5 to 30 parts by weight. When the ethylenically unsaturated compound (C) is contained, 2 to 50 parts by weight of the total of 100 parts by weight of the oxetane compound (A), the epoxy compound (B) and the ethylenically unsaturated compound (C) is added. It is preferably parts by weight, particularly preferably 3 to 40 parts by weight, and even more preferably 5 to 30 parts by weight. If the content of the silane coupling agent (D) is too large, the liquid stability tends to decrease, and the durability (heat impact resistance) after curing tends to decrease. If the content is too small, the adhesiveness is further improved. Tends not be obtained sufficiently.

<Photocationic polymerization initiator (E)>
In the present invention, it is preferable that the adhesive composition further contains the photocationic polymerization initiator (E). By using the photocationic polymerization initiator (E), the adhesive composition can be cured at room temperature (25 ° C. ± 10 ° C.), and the protective film and the polarizer can be adhered well. .. The photocationic polymerization initiator (E) is a compound that produces a cationic species or Lewis acid by irradiation with active energy rays, and is, for example, an onium salt such as an aromatic diazonium salt, an aromatic iodonium salt, or an aromatic sulfonium salt. , Iron-allene complex and the like.

Examples of the aromatic diazonium salt include benzenediazonium / hexafluoroantimonate, benzenediazonium / hexafluorophosphate, benzenediazonium / hexafluoroborate and the like.

Examples of the aromatic iodonium salt include diphenyliodonium / tetrakis (pentafluorophenyl) borate, diphenyliodonium / hexafluorophosphate, diphenyliodonium / hexafluoroantimonate, di (4-nonylphenyl) iodonium / hexafluorophosphate and the like. can give.

Examples of the aromatic sulfonium salt include triphenylsulfonium / hexafluorophosphate, triphenylsulfonium / hexafluoroantimonate, triphenylsulfonium / tetrakis (pentafluorophenyl) borate, and diphenyl [4- (phenylthio) phenyl] sulfonium. Hexafluorophosphate, 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexafluorophosphate, 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate, 4,4'-Bis [di (β-hydroxyethoxy) phenylsulfonium] diphenylsulfide bishexafluorophosphate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [Di (p-toluyl) Sulfonio] -2-Isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate, 4- (p-tert-butyl) Phenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) ) Volate etc. can be mentioned.

Examples of the iron-allene complex include xylene-cyclopentadienyl iron (II) -hexafluoroantimonate, cumene-cyclopentadienyl iron (II) -hexafluorophosphate, and xylene-cyclopentadienyl iron (II). ) -Tris (trifluoromethylsulfonyl) metanide and the like.

Among such photocationic polymerization initiators (E), it is preferable to use an aromatic iodonium salt or an aromatic sulfonium salt from the viewpoint of reacting with a light source having a long wavelength with high sensitivity.
The photocationic polymerization initiator (E) can be used alone or in combination of two or more.

The content of the photocationic polymerization initiator (E) is preferably 0.5 to 20 parts by weight, particularly 1. It is preferably 0 to 15 parts by weight, more preferably 1.5 to 10 parts by weight. If the content of the photocationic polymerization initiator (E) is too large, the solubility tends to decrease or the durability tends to decrease. Further, if the content of the photocationic polymerization initiator (E) is too small, the curing tends to be insufficient, and the mechanical strength and the adhesive strength tend to decrease.

<Photoradical polymerization initiator (F)>
In the present invention, when a radical polymerization component is contained, a photoradical polymerization initiator (F) can be further used. Examples of the photoradical polymerization initiator (F) include acetophenones, benzophenones, thioxanthones, acylphosphon oxides and the like. These photoradical polymerization initiators (F) can be used alone or in combination of two or more.

In addition, as these auxiliaries, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethyl benzoic acid, 4-dimethylaminobenzoic acid Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, 4-dimethylaminobenzoate isoamyl, 4-dimethylaminobenzoate 2-ethylhexyl, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanson Etc. can be used together.

Among these photoradical polymerization initiators (F), it is preferable to use acylphosphine oxides, and in particular, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl)-. 2,4,4-trimethyl-pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide are preferable, and 2,4,6-trimethylbenzoyl-phenylphosphine oxide and bis are also preferable. It is preferable to use (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.

When the photoradical polymerization initiator (F) is contained, the content is preferably 20 parts by weight or less, particularly 0.1 to 20 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound (C). It is preferably parts by weight, more preferably 0.5 to 10 parts by weight. If the content of the photoradical polymerization initiator (F) is too large, the solubility of the photoradical polymerization initiator tends to decrease and the durability of the adhesive layer tends to decrease. Further, if the content of the photoradical polymerization initiator (F) is too small, the curing tends to be insufficient, and the adhesive strength and mechanical strength of the adhesive layer tend to decrease.

When the photoradical polymerization initiator (F) is used in combination with the photocationic polymerization initiator (E), the content weight ratio of the two is the photocationic polymerization initiator (E) / photoradical from the viewpoint of compatibility and reactivity. The polymerization initiator (F) = 20/1 to 1/20, more preferably the photocationic polymerization initiator (E) / photoradical polymerization initiator (F) = 15/1 to 1/10, in particular. Preferably, the photocationic polymerization initiator (E) / photoradical polymerization initiator (F) = 10/1 to 1/5.

Further, in particular, in terms of curing efficiency (which can be efficiently cured with a small irradiation amount of active energy rays), a preferable combination of the photocationic polymerization initiator (E) and the photoradical polymerization initiator (F) is a photocation. When an aromatic sulfonium salt or an aromatic iodonium salt is used as the polymerization initiator (E), it is a combination in which acylphosphine oxides are used as the photoradical polymerization initiator (F).

In addition to the above components, the adhesive composition of the present invention includes photosensitizers, polyols, antistatic agents, other adhesives, acrylic resins, urethane resins, as long as the effects of the present invention are not impaired. Adhesives, plasticizers, colorants such as rosin, rosin ester, hydrogenated rosin ester, phenol resin, aromatic-modified terpene resin, aliphatic petroleum resin, alicyclic petroleum resin, styrene resin, xylene resin, etc. , Fillers, anti-aging agents, UV absorbers, functional pigments and other additives, and compounds that cause color development or discoloration by UV or irradiation can be blended. The blending amount of these additives is appropriately set for each additive, but for example, it is preferably 30% by weight or less, and particularly preferably 20% by weight or less of the entire adhesive composition.
In addition to the above additives, a small amount of impurities and the like contained in the raw materials for producing the constituent components of the adhesive composition may be contained.

By using this photosensitizer, the reactivity can be improved, and the mechanical strength and adhesive strength of the cured product can be improved.
Examples of the photosensitizer include anthracene derivatives such as 9,10-dibutoxyanthracene; benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4. Benzophenone derivatives such as -dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone; anthracene such as 2-chloroanthraquinone and 2-methylanthraquinone. Carbonyl compounds such as derivatives; organic sulfur compounds such as thioxanthone derivatives such as 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthene-9-one; persulfides, redox compounds, azo and diazo compounds , Halogen compounds, photoreducing dyes and the like. These can be used alone or in combination of two or more. Of these, it is preferable to use an anthracene derivative and a thioxanthone derivative.
The photosensitizer is preferably contained in the range of 0.01 to 20 parts by weight when the total amount of the photocationic polymerization initiator (E) and the photoradical polymerization initiator (F) is 100 parts by weight. .. If the content of the photosensitizer is too high, the adhesive composition and the obtained adhesive layer tend to be colored, and if it is too low, the reactivity tends to decrease and the sensitizing effect tends not to be obtained. ..

<Adhesive composition>
The adhesive composition of the present invention can be obtained by blending and mixing each of the above components in a predetermined ratio.

In this way, the active energy ray-curable adhesive composition of the present invention is obtained. The active energy ray-curable adhesive composition of the present invention becomes an adhesive by being cured by irradiation with active energy rays, and is suitable as an adhesive for a polarizing plate for adhering a polarizer and a protective film. It can be used for.

<Polarizer>
The polarizing plate of the present invention is obtained by bonding a polarizing element and a protective film via a polarizing plate adhesive, and more specifically, for the polarizing plate of the present invention, on at least one surface, preferably both sides of the polarizing element. Protective films are bonded together using an adhesive. Usually, a liquid polarizing plate adhesive composition is uniformly applied to a polarizing element surface, a protective film surface, or both surfaces, and then both are applied. A polarizing plate is formed by laminating, crimping, and irradiating with active energy rays.

As the above-mentioned polarizer, usually, a film made of a PVA-based resin having an average degree of polymerization of 1,500 to 10,000 and a saponification degree of 85 to 100 mol% is used as a raw film, and an aqueous solution of iodine-potassium iodide or an aqueous solution of iodine-potassium iodide is used. A uniaxially stretched film dyed with a dichroic dye (usually a stretch ratio of 2 to 10 times, preferably about 3 to 7 times) is used.

The PVA-based resin is usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, but a small amount of unsaturated carboxylic acids (including salts, esters, amides, nitriles, etc.), olefins, vinyl ethers, etc. It may contain a component copolymerizable with vinyl acetate, such as an unsaturated sulfonate. Further, examples thereof include so-called polyvinyl acetal resins such as polyvinyl butyral resin and polyvinyl formal resin and PVA derivatives obtained by reacting PVA with aldehydes in the presence of acid.

As the protective film for the polarizing plate, an acrylic film, a polyethylene film, a polypropylene film, a cycloolefin film or the like can be used in addition to the conventional TAC film, and the adhesive composition of the present invention is a TAC film. It is suitably used for any protective film selected from films, acrylic films, cycloolefin films, polyethylene terephthalate (PET) films and the like.

When the adhesive composition of the present invention is applied onto a polarizer or a protective film, for example, a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, etc. A rod coater or the like can be used, or coating can be performed by a dipping method.

At the time of the above bonding and crimping, for example, a roll laminator or the like can be used, and the pressure is usually selected from the range of 0.1 to 10 MPa.

As the active energy rays, in addition to far-ultraviolet rays, ultraviolet rays, near-ultraviolet rays, rays such as infrared rays, electromagnetic waves such as X-rays and γ-rays, electron beams, proton rays, neutron rays and the like can be used. Curing by ultraviolet irradiation is advantageous because of its availability and price.

As the light source for irradiating the ultraviolet rays, a high-pressure mercury lamp, an electrodeless lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, an LED lamp and the like are used.
The above-mentioned ultraviolet irradiation is usually carried out under the condition of ^{2 to 3000 mJ / cm 2} , preferably 10 to 2000 mJ / cm 2.

Especially in the case of the high-pressure mercury lamp, for example, usually 5~3000mJ / cm ^2, preferably at the conditions of 50~2000mJ / cm ^2.
Further, in the case of the electrodeless lamp, for example, it is usually carried out under the condition of ^{2 to 2000 mJ / cm 2} , preferably 10 to 1000 mJ / cm 2.

The irradiation time varies depending on the type of light source, the distance between the light source and the coated surface, the coating thickness, and other conditions, but is usually several seconds to several tens of seconds, and in some cases, a fraction of a second. On the other hand, in the case of the above-mentioned electron beam irradiation, for example, it is preferable to use an electron beam having an energy in the range of 50 to 1000 keV and set the irradiation amount to 2 to 50 Mrad.

The irradiation direction of the active energy rays (ultraviolet rays, electron beams, etc.) can be any suitable direction, but it is preferable to irradiate the active energy rays from the transparent protective film side in order to prevent deterioration of the polarizer.

The thickness of the adhesive layer in the polarizing plate of the present invention obtained as described above is usually 0.1 to 10 μm, preferably 0.2 to 5 μm, particularly preferably 0.3 to 3 μm, and further preferably 0.5 to 2 μm. 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 processability of the polarizing plate tends to decrease due to cracking during punching.

The active energy ray-curable adhesive composition of the present invention is suitable for bonding various protective films for polarizing plates and a polarizer, and exhibits extremely excellent adhesiveness.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the example, the term "part" means a weight standard.

Prior to Examples and Comparative Examples, each component of the adhesive composition shown below was prepared.

[Oxetane compound (A)]
(A-1) 3-Ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (oxetane compound having two oxetane group in the molecule: "Aron oxetane OXT-221" manufactured by Toagosei Co., Ltd. ")

[Epoxy compound (B)]
[Aliphatic epoxy compound (B1)]
(B1-1) 1,4-Butanediol Diglycidyl Ether (“EX-214L” manufactured by Nagase ChemteX Corporation)
[Aromatic epoxy compound (B2)]
(B2-1) Bisphenol A type epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation)

[Ethylene unsaturated compound (C)]
(C-1) Neopentyl glycol diacrylate (Light acrylate NP-A manufactured by Kyoeisha Chemical Co., Ltd.)

[Silane Coupling Agent (D)]
(D-1) Glycidyloxy group-containing silane coupling agent (“KBM-403” manufactured by Shinetsu Silicone Co., Ltd.)

[Photocationic polymerization initiator (E)]
(E-1) Diphenyl [4- (Phenylthio) phenyl] Sulfonium hexafluorophosphate (aromatic sulfonium salt: "CPI-100P" manufactured by San Apro Co., Ltd.)

[Photoradical polymerization initiator (F)]
(F-1) 2,4,6-trimethylbenzoyl-phenylphoshin oxide (Irgacure TPO manufactured by BASF)

[Examples 1 to 8 and Comparative Examples 1 to 2]
<Preparation of active energy ray-curable adhesive composition>
Each of the above-mentioned compounding components was blended in the ratio shown in Table 1 below and mixed to prepare an active energy ray-curable adhesive composition.
The obtained active energy ray-curable adhesive composition was used as an adhesive composition for a polarizing plate and evaluated as follows.

<Making a polarizer>
First, a 60 μm PVA film was stretched 1.5 times while being immersed in a water tank having a water temperature of 30 ° C. Next, it was stretched 1.3 times while being immersed in a dyeing tank (30 ° C.) composed of 0.2 g / L of iodine and 15 g / L of potassium iodide for 240 seconds. Further, it was immersed in a boric acid treatment tank (50 ° C.) having a composition of 50 g / L of boric acid and 30 g / L of potassium iodide, and at the same time, boric acid treatment was carried out for 5 minutes while uniaxially stretching 3.08 times. Then, it was dried at 90 ° C. to produce a polarizer having a total draw ratio of 6 times.

<Preparation of polarizing plate test piece>
TAC film with a size of 200 mm x 150 mm and a thickness of 60 μm (manufactured by Fuji Film Co., Ltd., trade name "Fujitac") and cyclic olefin resin (COP) film with a size of 200 mm x 150 mm and a thickness of 50 μm (manufactured by Nippon Zeon Co., Ltd., trade name) Each film of "ZEONOR") was coated with the adhesive composition obtained above with a bar coater so as to have a film thickness of 3 μm to obtain a film with an adhesive composition. Then, each film with an adhesive composition layer was laminated on both sides of the above-mentioned polarizer having a size of 180 mm × 120 mm, and bonded at a nip pressure of 2 MPa using a roll machine to obtain a laminated film (layer of laminated film). Composition: TAC film / polarizer / COP film).

Then, from the COP film side of the laminated film, ultraviolet irradiation was performed with an ultraviolet irradiation device equipped with a high-pressure mercury lamp at a peak illuminance of 130 mW / cm ² and an integrated exposure amount of 300 mJ / cm ² (wavelength 365 nm). The composition was cured to prepare a test piece of a polarizing plate.
Using the polarizing plate test piece obtained above, the performance was evaluated as follows.

<Performance evaluation>
[Curability]
The interface between the polarizer and the TAC film was peeled off with a cutter knife, and the tackiness of the peeled portion was confirmed (touched by a finger).
(Evaluation criteria)
○… Tackiness did not remain.
×… Tackiness remained.

〔Adhesiveness〕
The polarizing plate test piece was cut into a size of 120 mm × 25 mm, and the adhesion between the TAC film and the polarizer and the COP film and the polarizer when stressed in the 90 ° direction was evaluated according to the following criteria.
(Evaluation criteria)
◎… It was particularly firmly adhered.
○… It was firmly adhered.
△… Weakly adhered.
×… It was not glued.

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

[Durability (heat impact resistance)]
A thermal shock test was carried out in which the test piece was cut into 100 mm × 100 mm, left at −40 ° C. for 30 minutes, and then left at 85 ° C. for 30 minutes, repeating a cycle of 100 times. After the test, evaluation was performed according to the following criteria.
(Evaluation method)
○… No appearance defects were confirmed.
×: Poor appearance (cracks occurred in the polarizer layer) was confirmed.

From the above results, the adhesive compositions of Examples 1 to 3 containing the oxetane compound (A) and the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2) in a specific ratio are good. It can be seen that it has excellent curability, is excellent in adhesiveness between the polarizer and the protective film, and is also excellent in water resistance and durability. From this, it can be seen that it is practically suitable as an adhesive composition for a polarizing plate having an excellent balance of various performances. Further, the products 4 and 5 containing the ethylenically unsaturated compound (C) are also excellent in terms of each performance in a well-balanced manner, and further, the products 3 and 5 containing the silane coupling agent (D) are excellent. The product gave even better results, especially with respect to adhesion.

On the other hand, in the adhesive compositions of Comparative Examples 1 and 2 in which the ratios of the oxetane compound (A) and the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2) were out of the specific range, The result was that either the curability or the adhesive strength was inferior. From this, it can be said that all of the various performances cannot be satisfied, and it cannot be put into practical use as an adhesive composition for a polarizing plate.
From the above, it was found that the adhesive composition of the present invention is very excellent particularly in the use of an adhesive for polarizing plates.

The adhesive composition of the present invention and the adhesive composition for a polarizing plate composed of the above-mentioned adhesive composition are excellent in adhesiveness between a polarizing element and a protective film, and various protective films for a polarizing plate and a polarizing element. Suitable for bonding with. Further, in addition to adhesiveness, it is excellent in all of curability, water resistance of the polarizing plate, durability, and particularly thermal shock resistance in a well-balanced manner. In addition to the above-mentioned adhesive applications for polarizing plates, the adhesive composition of the present invention can be used for, for example, bonding various optical films or sheets, or bonding electronic parts, precision instruments, packaging materials, display materials, and the like. It can also be used for.

Claims (11)

An active energy ray-curable resin composition containing an oxetane compound (A) and an epoxy compound (B), wherein the epoxy compound (B) is an aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2). ) containing, and the content of the oxetane compound (a), aliphatic epoxy compound (B1) and an aromatic epoxy compound (B2) Ri 75-200 parts by der per 00 parts by weight,
The content weight ratio of the aliphatic epoxy compound (B1) and the aromatic epoxy compound (B2) is active energy to (B1) / (B2) = 1 / 1~9 / 1 der wherein Rukoto Epoxy adhesive composition. The active energy ray-curable adhesive according to claim 1, wherein the content ratio of the oxetane compound (A) is 30% by weight or more based on the total amount of the oxetane compound (A) and the epoxy compound (B). Agent composition. The epoxy compound (B) contains an aliphatic epoxy compound (B1), and the content ratio of the aliphatic epoxy compound (B1) is relative to the total amount of the oxetan compound (A) and the epoxy compound (B). The active energy ray-curable adhesive composition according to claim 1 or 2, wherein the content is 5 to 60% by weight. The active energy ray-curable adhesive according to any one of claims 1 to 3 , further comprising an unsaturated compound (C) having at least one ethylenically unsaturated group in the molecule. Agent composition. The content of the unsaturated compound (C) having an ethylenically unsaturated group is 2 to 100 parts by weight with respect to 100 parts by weight of the total of the oxetane compound (A) and the epoxy compound (B). The active energy ray-curable adhesive composition according to claim 4. The active energy ray-curable adhesive composition according to any one of claims 1 to 5 , further comprising a silane coupling agent (D). The activity according to claim 6 , wherein the content of the silane coupling agent (D) is 2 to 50 parts by weight based on 100 parts by weight of the total of the oxetane compound (A) and the epoxy compound (B). Energy ray curable adhesive composition. The content of the silane coupling agent (D) is 2 to 50 parts by weight based on 100 parts by weight of the total of the oxetane compound (A), the epoxy compound (B) and the unsaturated compound (C) having an ethylenically unsaturated group. The active energy ray-curable adhesive composition according to claim 6 or 7 , characterized in that it is a part. An adhesive composition for a polarizing plate, which comprises the active energy ray-curable adhesive composition according to any one of claims 1 to 8. An adhesive for a polarizing plate, which is a cured product of the adhesive composition for a polarizing plate according to claim 9. A polarizing plate characterized in that a polarizing element and a protective film are bonded to each other via the polarizing plate adhesive according to claim 10.