KR20200141535A - Curable adhesive for polarizing films, polarizing film, optical film and image display device - Google Patents

Abstract

When the curable adhesive for polarizing films containing the curable component of the present invention is immersed in pure water at 23° C. for 24 hours, the cured product of the curable adhesive for polarizing films is the following formula:
Bulk absorption rate (%) = Formula: ｛(M2-M1)/M1｝×100 (%),
However, in the above formula, M1 represents the weight of the cured product before immersion, and M2 represents the weight of the cured product after immersion. The curable adhesive for polarizing film has good adhesiveness between a polarizer and a transparent protective film, and can satisfy optical durability in a harsh environment under high temperature and high humidity, and provides sufficient adhesive strength even when immersed in water for a long time. Have.

Description

Curable adhesive for polarizing film, polarizing film, optical film, and image display device {CURABLE ADHESIVE FOR POLARIZING FILMS, POLARIZING FILM, OPTICAL FILM AND IMAGE DISPLAY DEVICE}

The present invention relates to a curable adhesive for polarizing films forming the adhesive layer in a polarizing film in which a polarizer and a transparent protective film are laminated through an adhesive layer. Moreover, this invention relates to a polarizing film using the said adhesive layer. The said polarizing film can form image display devices, such as a liquid crystal display device (LCD), an organic EL display device, CRT, and PDP, as this alone or as an optical film laminated therewith.

In watches, mobile phones, PDAs, notebook PCs, PC monitors, DVD players, and TVs, liquid crystal displays are rapidly expanding the market. A liquid crystal display device visualizes a polarization state by switching of a liquid crystal, and a polarizer is used in its display principle. In particular, in applications such as TVs, more and more high luminance, high contrast, and wide viewing angle are required, and even more and more high transmittance, high polarization, and high color reproducibility are required for polarizing films.

As a polarizer, since it has high transmittance and high polarization, for example, iodine is adsorbed to polyvinyl alcohol (hereinafter, also simply referred to as "PVA"), and an iodine polarizer having a stretched structure is most commonly used. In general, a polarizing film is a so-called water-based adhesive in which a polyvinyl alcohol-based material is dissolved in water, and a transparent protective film is bonded on both sides of a polarizer is used (Patent Document 1 and Patent Document 2 below). . As the transparent protective film, triacetyl cellulose or the like having high moisture permeability is used. In the case of using the water-based adhesive (so-called wet lamination), after bonding a polarizer and a transparent protective film, a drying step is required.

On the other hand, instead of the water-based adhesive, an active energy ray-curable adhesive has been proposed. When manufacturing a polarizing film using an active energy ray-curable adhesive, since a drying process is not required, productivity of a polarizing film can be improved. For example, radical polymerization type active energy ray-curable adhesives using an N-substituted amide-based monomer as a curable component have been proposed (Patent Document 3 and Patent Document 4 below). Such adhesives exhibit excellent durability under harsh environments under high humidity and high temperatures, but in the market, an adhesive capable of further improving adhesiveness and/or water resistance has been demanded.

In addition, by paying attention to the SP value (solubility parameter) of the curable component and using at least three radical polymerizable compounds having different SP values in a predetermined composition ratio, the activity capable of forming an adhesive layer with improved durability and water resistance An energy ray-curable adhesive has been proposed (Patent Document 5 below).

Japanese Patent Application Laid-Open No. 2006-220732 Japanese Unexamined Patent Publication No. 2001-296427 Japanese Patent Application Laid-Open No. 2008-287207 Japanese Unexamined Patent Publication No. 2010-078700 Japanese Laid-Open Patent Publication No. 2012-144690

According to the active energy ray-curable adhesive described in Patent Document 5, durability and water resistance can be satisfied with respect to various transparent protective films used in manufacturing a polarizing film. However, the polarizing film obtained by using the active energy ray-curable adhesive described in Patent Document 5 can satisfy the water resistance (hot water immersion test) when immersed in hot water at 60°C for 6 hours, but in the market, further high temperature and high humidity Optical durability under harsh environments under the conditions is required. Furthermore, the polarizing film is required to have sufficient adhesive strength even when immersed in water for a long time.

The present invention is a curable type for a polarizing film that has good adhesion between a polarizer and a transparent protective film, and can satisfy optical durability in harsh environments under high temperature and high humidity, and has sufficient adhesion even when immersed in water for a long time. It aims to provide an adhesive.

In addition, the present invention provides a polarizing film in which a transparent protective film is formed on a polarizer by an adhesive layer formed using a curable adhesive for polarizing films, and further provides an optical film using the polarizing film, Furthermore, an object of the present invention is to provide an image display device using the polarizing film or optical film.

The present inventors, as a result of repeated intensive examination in order to solve the above problem, found that the above object can be achieved by the following curable adhesive for polarizing films, and came to solve the present invention.

That is, the present invention is a curable adhesive for polarizing films containing a curable component,

When the curable adhesive for polarizing films is immersed in a 23°C pure water for 24 hours, the cured product obtained by curing the curable adhesive is the following formula:

Bulk absorption rate (%) =｛(M2-M1)/M1｝×100,

However, in the above formula, M1 represents the weight of the cured product before immersion, and M2 represents the weight of the cured product after immersion, and has a bulk water absorption rate of 10% by weight or less, It relates to a curable adhesive for polarizing films.

It is preferable that the said curable adhesive for polarizing film has an octanol/water partition coefficient (logPow value) of 1 or more.

The curable adhesive for polarizing films can be used as an active energy ray-curable adhesive when the curable component is an active energy ray-curable component. A radically polymerizable compound may be contained as the curable component. It is preferable that the radical polymerizable compound contains a (meth)acrylamide derivative. Further, as the radical polymerizable compound, it is preferable to contain a polyfunctional compound having at least two functional groups having radical polymerizable properties. Further, the active energy ray-curable adhesive may further contain a photoinitiator.

The curable adhesive for polarizing films may further contain an acrylic oligomer (A).

The curable adhesive for polarizing films may further contain a photoacid generator (B).

The curable adhesive for polarizing films may further contain a compound (C) containing either an alkoxy group or an epoxy group. As the compound (C) containing either an alkoxy group or an epoxy group, a compound (C1) containing an alkoxy group is preferable. Furthermore, it is preferable that the compound (C1) containing an alkoxy group is a melamine compound containing an alkoxy group.

In addition, the curable adhesive for polarizing films may further contain an isocyanate compound (D).

In the case where the curable component is a thermosetting component, the curable adhesive for polarizing films can be used as a thermosetting adhesive by further containing a thermal polymerization initiator.

In addition, the present invention is a polarizing film in which a transparent protective film is formed on at least one surface of a polarizer through an adhesive layer,

It relates to a polarizing film, characterized in that the adhesive layer is formed by a cured product layer of the curable adhesive for polarizing films.

In the polarizing film, it is preferable that the cured adhesive layer has a thickness of 0.1 to 3 µm.

Further, the present invention relates to an optical film, wherein at least one polarizing film is laminated.

Further, the present invention relates to an image display device, wherein the polarizing film or the optical film is used.

The curable adhesive for polarizing films of the present invention has a bulk water absorption of a cured product obtained by curing the curable adhesive of 10% by weight or less. This bulk water absorption rate shows that the water absorption property when an adhesive layer is formed with the cured material layer obtained from the curable adhesive for polarizing films of this invention is very low. Therefore, a polarizing film in which a transparent protective film is formed on a polarizer through an adhesive layer made of the cured product layer has good adhesion between the polarizer and the transparent protective film layer, and optical durability in a harsh environment under high temperature and high humidity. Can satisfy.

For example, a polarizing film having a cured product layer (adhesive layer) formed using the curable adhesive for polarizing films of the present invention is optical durability (humidification durability test) even under a severe humid environment (85°C x 85%RH) ) Is good. Therefore, even when the polarizing film of this invention is put under the said severe humidification environment, the fall (change) of the transmittance|permeability and polarization degree of a polarizing film can be suppressed small. In addition, the polarizing film of the present invention can suppress a decrease in adhesive strength even under a severe environment immersed in water, and can provide a polarizing film having sufficient adhesive strength even when immersed in water for a long time.

<Bulk absorption rate>

The curable adhesive for polarizing films of the present invention has a bulk water absorption of 10% by weight or less as measured when the cured product obtained by curing the curable adhesive is immersed in pure water at 23° C. for 24 hours. When the polarizing film is placed in an environment of extreme high temperature and high humidity (85°C/85%RH, etc.), moisture that has passed through the transparent protective film and the adhesive layer infiltrates the polarizer, and the crosslinked structure is hydrolyzed to cause orientation of the dichroic dye. This disturbance occurs, resulting in deterioration in optical durability such as an increase in transmittance and a decrease in polarization degree. By setting the bulk absorption rate of the adhesive layer to 10% by weight or less, the movement of water to the polarizer when the polarizing film is placed in an environment of extreme high temperature and high humidity is suppressed, and an increase in transmittance of the polarizer and a decrease in polarization degree can be suppressed. The bulk absorption rate is preferably 5% by weight or less, more preferably 3% by weight or less, furthermore, from the viewpoint of making the optical durability of the adhesive layer of the polarizing film more favorable in a harsh environment under high temperature. Is preferably 1.5% by weight or less, and most preferably 1% by weight or less. On the other hand, when bonding the polarizer and the transparent protective film, the polarizer holds a certain amount of moisture, and when the curable adhesive and the moisture contained in the polarizer come into contact, appearance defects such as cratering and air bubbles may occur. In order to suppress appearance defects, it is preferable that the curable adhesive can absorb a certain amount of moisture. More specifically, the bulk water absorption is preferably 0.01% by weight or more, and further preferably 0.05% by weight or more. Specifically, the bulk water absorption is measured by the water absorption test method described in JISK 7209.

It is preferable that the curable adhesive for polarizing films of the present invention has a high octanol/water partition coefficient (hereinafter, referred to as logPow value). The logPow value is an index indicating the lipophilicity of a substance, and means the logarithmic value of the octanol/water partition coefficient. A high logPow means that it is lipophilic, that is, a low absorption rate. The logPow value can also be measured (flask dipping method described in JIS-Z-7260), but can also be calculated based on the structure of each compound, which is a constituent component (curable component, etc.) of the curable adhesive for polarizing films. In this specification, the logPow value calculated by Chem Draw Ultra manufactured by Cambridge Soft is used.

Based on the above calculated value, the logPow value of the curable adhesive for polarizing films in the present invention can be calculated by the following equation.

LogPow of curable adhesive = Σ (logPowi × Wi)

logPowi: The logPow value of each component of the curable adhesive

Wi: (number of moles of i component)/(total number of moles of each component of curable adhesive)

In the above calculation, among the components of the curable adhesive, components that do not form a skeleton of a cured product (adhesive layer) such as a polymerization initiator or a photoacid generator are excluded from the components in the calculation. The logPow value of the curable adhesive for polarizing films of the present invention is preferably 1 or more, more preferably 1.5 or more, and most preferably 2 or more. This can increase the adhesion water resistance and humidification durability. On the other hand, the logPow value of the curable adhesive for polarizing films of the present invention is usually about 8 or less, preferably 5 or less, and more preferably 4 or less. If this logPow value is too high, as described above, appearance defects such as cratering and air bubbles tend to occur, which is not preferable.

In addition, the means for making the bulk water absorption to 10% by weight or less in the present invention is not particularly limited, but in the case of a composition in which the curable adhesive for a polarizing film contains a plurality of components, it is within the above range by selecting each component. It is possible to control the bulk absorption rate. For example, in the case of an adhesive composition containing a plurality of components, the curable adhesive for a polarizing film is prepared so that the ratio of the component whose logPow value is 1 or less in the adhesive composition is reduced. It is possible to control the bulk absorption rate. In order to adjust the said bulk water absorption in this invention to 10 weight% or less, it can implement by controlling the logPow value of the curable adhesive for polarizing films to 1 or more, for example.

<hardening shrinkage rate>

Moreover, since the curable adhesive for polarizing films of the present invention has a curable component, when the curable adhesive is cured, cure shrinkage usually occurs. The curing shrinkage ratio is an index showing the ratio of curing shrinkage in forming the adhesive layer from the curable adhesive for polarizing films. When the curing shrinkage ratio of the adhesive layer is increased, it is preferable to cure the curable adhesive for polarizing films to prevent interfacial deformation from occurring when forming the adhesive layer, thereby suppressing the occurrence of poor adhesion. From the above viewpoint, it is preferable that the cured shrinkage ratio of the cured product obtained by curing the curable adhesive for polarizing films of the present invention is 10% or less. The hardening shrinkage ratio is preferably small, and the hardening shrinkage ratio is preferably 8% or less, and further preferably 5% or less. The said cure shrinkage rate is measured by the method described in Unexamined-Japanese-Patent No. 2013-104869, and specifically, it is measured by the method by the method of the Sentec Co., Ltd. cure shrinkage sensor described in Examples.

<curable ingredients>

The curable adhesive for polarizing films of the present invention contains a curable component. The curable component is appropriately selected so that the cured product satisfies the bulk water absorption rate.

As the curable component, it can be broadly divided into an active energy ray curing type such as an electron beam curing type, an ultraviolet curing type, and a visible ray curing type, and a thermosetting type. Furthermore, UV-curable and visible-ray-curable adhesives can be classified into radical polymerization curable adhesives and cation polymerization adhesives. In the present invention, active energy rays having a wavelength range of 10 nm to less than 380 nm are indicated as ultraviolet rays, and active energy rays having a wavelength range of 380 nm to 800 nm are indicated as visible rays. The curable component of the radical polymerization curable adhesive can be used as a curable component of a thermosetting adhesive.

<1: Radical polymerization curable adhesive>

As said curable component, a radical polymerizable compound used for a radical polymerization curable adhesive is mentioned, for example. Examples of the radical polymerizable compound include compounds having a radically polymerizable functional group of a carbon-carbon double bond such as a (meth)acryloyl group and a vinyl group. These curable components can be used either as a monofunctional radical polymerizable compound or a bifunctional or more polyfunctional radical polymerizable compound. Moreover, these radically polymerizable compounds can be used singly or in combination of two or more. As these radical polymerizable compounds, a compound having a (meth)acryloyl group is preferable, for example. In addition, in this invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning as follows.

<< monofunctional radical polymerizable compound >>

As a monofunctional radical polymerizable compound, a (meth)acrylamide derivative which has a (meth)acrylamide group is mentioned, for example. The (meth)acrylamide derivative is preferable in securing adhesiveness with a polarizer and various transparent protective films, and also because the polymerization rate is high and productivity is excellent. Specific examples of the (meth)acrylamide derivative include, for example, N-methyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and N-isopropyl. N-alkyl group-containing (meth)acrylamide derivatives such as (meth)acrylamide, N-butyl (meth)acrylamide, and N-hexyl (meth)acrylamide; N-methylol (meth)acrylamide, N-hydroxy N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as ethyl (meth)acrylamide and N-methylol-N-propane (meth)acrylamide; aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide N-aminoalkyl group-containing (meth)acrylamide derivatives such as; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; mercaptomethyl (meth)acryl N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as amide and mercaptoethyl (meth)acrylamide; etc. are mentioned. In addition, as a heterocycle-containing (meth)acrylamide derivative in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle, for example, N-acryloylmorpholine, N-acryloylpiperidine, N- Methacryloyl piperidine, N-acryloyl pyrrolidine, etc. are mentioned.

Among the above (meth)acrylamide derivatives, N-hydroxyalkyl group-containing (meth)acrylamide derivatives are preferable from the viewpoint of adhesiveness to polarizers and various transparent protective films, and in particular, N-hydroxyethyl (meth)acrylic Amide is preferred.

Moreover, as a monofunctional radical polymerizable compound, various (meth)acrylic acid derivatives which have a (meth)acryloyloxy group are mentioned, for example. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) Acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (Meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylic (Meth)acrylic acid (carbon number 1 to 20) alkyl esters such as acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and n-octadecyl (meth)acrylate Can be mentioned.

In addition, as the (meth)acrylic acid derivative, for example, cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate;

Aralkyl (meth)acrylates such as benzyl (meth)acrylate;

2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl Polycyclic (meth)acrylates such as (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and the like;

2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethylcarbitol ( Alkoxy group or phenoxy group-containing (meth)acrylates such as meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxypolyethylene glycol (meth)acrylate; and the like.

In addition, examples of the (meth)acrylic acid derivative include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. )Acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12- Hydroxyalkyl (meth)acrylates such as hydroxylauryl (meth)acrylate, [4-(hydroxymethyl)cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth)acrylate, 2-hydroxyl (Meth)acrylate containing hydroxyl groups, such as oxy-3-phenoxypropyl (meth)acrylate;

Epoxy group-containing (meth)acrylates, such as glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether;

2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth) Halogen-containing (meth)acrylates such as acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate;

Alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate;

3-oxetanylmethyl(meth)acrylate, 3-methyl-oxetanylmethyl(meth)acrylate, 3-ethyl-oxetanylmethyl(meth)acrylate, 3-butyl-oxetanylmethyl(meth) ) Oxetane group-containing (meth)acrylates, such as acrylate and 3-hexyl-oxetanylmethyl (meth)acrylate;

(Meth)acrylates having heterocyclic rings such as tetrahydrofurfuryl (meth)acrylate, butyrolactone (meth)acrylate, hydroxypivalate neopentyl glycol (meth)acrylic acid adduct, p-phenylphenol (Meth)acrylate, etc. are mentioned.

Moreover, as a monofunctional radical polymerizable compound, carboxyl group-containing monomers, such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, are mentioned.

In addition, examples of monofunctional radical polymerizable compounds include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinyl And vinyl monomers having a nitrogen-containing heterocycle such as pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, and vinyl morpholine.

Moreover, as the monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. The radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acryl group at the terminal or in the molecule, and further having an active methylene group. As an active methylene group, an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group, etc. are mentioned, for example. It is preferable that the active methylene group is an acetoacetyl group. Specific examples of the radical polymerizable compound having an active methylene group include, for example, 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, and 2-acetoacetoxy-1-methylethyl ( Acetoacetoxyalkyl (meth)acrylate such as meth)acrylate; 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoa) Cetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, N-(2-acetoacetylaminoethyl)acrylamide, etc. I can. It is preferable that the radically polymerizable compound having an active methylene group is acetoacetoxyalkyl (meth)acrylate.

≪Multifunctional radical polymerizable compound≫

Moreover, as a bifunctional or more polyfunctional radical polymerizable compound, for example, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonandiol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A Ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol di(meth)acrylate, tricyclo Decanedimethanoldi(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth) (Meth) such as acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, EO modified diglycerin tetra (meth) acrylate, etc. An esterified product of acrylic acid and a polyhydric alcohol, and 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene are mentioned. As specific examples, Aaronix M-220, M-306 (manufactured by Toa Synthetic Corporation), light acrylate 1,9 ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), and light Acrylate DCP-A (manufactured by Kyoeisha Chemicals), SR-531 (manufactured by Sartomer), CD-536 (manufactured by Sartomer), and the like. Moreover, various types of epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate-based monomers, etc. may be mentioned as needed.

It is preferable that the radical polymerizable compound contains the polyfunctional radical polymerizable compound in order to control the water absorption rate of the cured product and to satisfy the optical durability of the polarizing film in a harsh humid environment. Among the polyfunctional radical polymerizable compounds, those having a high logPow value are preferred. The logPow value of the radically polymerizable compound is preferably 2 or more, more preferably 3 or more, and most preferably 4 or more.

As a radically polymerizable compound having a high logPow value, for example, alicyclic (meth) such as tricyclodecanedimethanoldi(meth)acrylate (logPow = 3.05) and isobornyl (meth)acrylate (logPow = 3.27) Acrylate;

Long-chain aliphatic (meth)acrylates such as 1,9-nonandiol di(meth)acrylate (logPow = 3.68) and 1,10-decanediol diacrylate (logPow = 4.10);

Multibranched (meth)acrylates such as hydroxypivalate neopentyl glycol (meth)acrylic acid adduct (logPow = 3.35) and 2-ethyl-2-butylpropanediol di(meth)acrylate (logPow = 3.92);

Bisphenol A di(meth)acrylate (logPow = 5.46), bisphenol A ethylene oxide 4 mole adduct di(meth)acrylate (logPow = 5.15), bisphenol A propylene oxide 2 mole adduct di(meth)acrylate (logPow = 6.10), bisphenol A propylene oxide 4 mol adduct di(meth)acrylate (logPow = 6.43), 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene ( (meth)acrylate containing aromatic rings such as logPow = 7.48) and p-phenylphenol (meth)acrylate (logPow = 3.98);

And the like.

As for the radical polymerizable compound, it is preferable to use a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound in combination from the viewpoint of achieving both adhesiveness with a polarizer and various transparent protective films, and optical durability in harsh environments. . Usually, it is preferable to use together in the ratio of 3 to 80 weight% of a monofunctional radical polymerizable compound and 20 to 97 weight% of a polyfunctional radical polymerizable compound with respect to 100 weight% of a radical polymerizable compound.

<Mode of radical polymerization curable adhesive>

The curable adhesive for polarizing films of the present invention can be used as an active energy ray-curable adhesive when a curable component is used as an active energy ray-curable component, and as a thermosetting adhesive when a curable component is used as a thermosetting component. When the active energy ray-curable adhesive uses an electron beam or the like as an active energy ray, the active energy ray-curable adhesive does not need to contain a photoinitiator, but when an ultraviolet ray or visible ray is used for the active energy ray. It is preferable to contain a photoinitiator. On the other hand, when the curable component of the adhesive is used as a thermosetting component, it is preferable that the adhesive contains a thermal polymerization initiator.

≪Photo polymerization initiator≫

The photoinitiator in the case of using a radical polymerizable compound is appropriately selected by an active energy ray. In the case of curing with ultraviolet or visible light, a photopolymerization initiator of ultraviolet or visible light cleavage is used. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl ( Aromatic ketone compounds such as 2-hydroxy-2-propyl) ketone, α-hydroxy-α,α′-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α-hydroxycyclohexylphenyl ketone Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholino Acetophenone compounds such as propane-1; Benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; and aromatic ketals such as benzyl dimethyl ketal Decomposition compounds; Aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; Thioxanthone , 2-chloro thioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, 2,4-dichloro thioxanthone, 2,4-diethyl thioxanthone, 2 Thioxanthone compounds such as ,4-diisopropyl thioxanthone and dodecyl thioxanthone; camphorquinone; halogenated ketone; acylphosphinoside; acylphosphonate and the like. Among the photoinitiators, those having a high logPow value are preferred. The photoinitiator is not included in the component in the calculation of the logPow value of the curable adhesive for polarizing films, but the logPow value of the photoinitiator is preferably 1 or more, more preferably 2 or more, most preferably 3 That's it.

The blending amount of the photoinitiator is 20 parts by weight or less based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The blending amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight, further preferably 0.05 to 10 parts by weight, and further preferably 0.1 to 5 parts by weight.

In addition, when using the curable adhesive for polarizing films of the present invention in a visible ray-curable type containing a radical polymerizable compound as a curable component, it is particularly preferable to use a photoinitiator having high sensitivity to light of 380 nm or more. A photoinitiator that is highly sensitive to light of 380 nm or more will be described later.

As the photoinitiator, a compound represented by the following general formula (1);

[Formula 1]

(In the formula, R ¹ and R ² represent -H, -CH ₂ CH ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different), or the general formula (1) It is preferable to use together the compound represented by and a photoinitiator which is highly sensitive to light of 380 nm or more described later. When a compound represented by the general formula (1) is used, it is superior in adhesiveness compared to the case where a photoinitiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are -CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound represented by the general formula (1) in the adhesive is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and 0.9 to 3 parts by weight based on 100 parts by weight of the total amount of the curable component. It is more preferable.

Moreover, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiation aid include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoa of 4-dimethylaminobenzoate. Wheat, and the like, and ethyl 4-dimethylaminobenzoate is particularly preferred. In the case of using a polymerization initiation aid, the amount added is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component. .

Moreover, a known photoinitiator can be used together as needed. Since the transparent protective film having UV absorbing ability does not transmit light of 380 nm or less, it is preferable to use a photoinitiator with high sensitivity to light of 380 nm or more as the photoinitiator. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-buta Non-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl -Diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro Ro-3-(1H-pyrrol-1-yl)-phenyl) titanium and the like.

In particular, as a photoinitiator, in addition to the photoinitiator of general formula (1), a compound further represented by the following general formula (2);

[Formula 2]

(In the formula, R ³ , R ⁴ and R ⁵ represent -H, -CH ₃ , -CH ₂ CH ₃ , -iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different) It is desirable to do. As the compound represented by the general formula (2), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan 1-one (trade name: IRGACURE907 manufacturer: BASF), which is also a commercial product, can be preferably used. . In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (brand name: IRGACURE369 manufacturer: BASF), 2-(dimethylamino)-2-[(4-methylphenyl )Methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (brand name: IRGACURE379 manufacturer: BASF) is preferable because it has high sensitivity.

<The radical polymerizable compound (a1) having an active methylene group and a radical polymerization initiator (a2) having a dehydrogenation action>

In the above-described active energy ray-curable adhesive, when a radical polymerizable compound (a1) having an active methylene group is used as the radical polymerizable compound, it is preferably used in combination with a radical polymerization initiator (a2) having a dehydrogenation function. . According to such a configuration, particularly even immediately after being taken out in a high humidity environment or in water (non-dried state), the adhesiveness of the adhesive layer of the polarizing film is remarkably improved. Although this reason is not clear, the following causes are considered. In short, the radical polymerizable compound (a1) having an active methylene group is absorbed into the main chain and/or side chain of the base polymer in the adhesive layer while being polymerized together with other radical polymerizable compounds constituting the adhesive layer, thereby forming the adhesive layer. To form. In this polymerization process, if the radical polymerization initiator (a2) having a dehydrogenation action is present, the base polymer constituting the adhesive layer is formed, while hydrogen is released from the radical polymerizable compound (a2) having an active methylene group, and methylene Radicals are generated in the group. Then, the methylene group in which the radical is generated and the hydroxyl group of a polarizer such as PVA react, thereby forming a covalent bond between the adhesive layer and the polarizer. As a result, even in a non-dried state, it is estimated that the adhesiveness of the adhesive layer which the polarizing film has is significantly improved.

In the present invention, examples of the radical polymerization initiator (a2) having a dehydrogenation action include a thioxanthone radical polymerization initiator, a benzophenone radical polymerization initiator, and the like. It is preferable that the said radical polymerization initiator (a2) is a thioxanthone type radical polymerization initiator. As a thioxanthone type radical polymerization initiator, the compound represented by said general formula (1) is mentioned, for example. As a specific example of the compound represented by General formula (1), thioxanthone, dimethyl thioxanthone, diethyl thioxanthone, isopropyl thioxanthone, chloro thioxanthone, etc. are mentioned, for example. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are -CH ₂ CH ₃ is particularly preferable.

When the active energy ray-curable adhesive contains a radical polymerizable compound (a1) having an active methylene group and a radical polymerization initiator (a2) having a dehydrogenation action, the total amount of the curable component is 100% by weight. , It is preferable to contain 1-50 weight% of the said radical polymerizable compound (a1) which has an active methylene group, and 0.1-10 weight part with respect to 100 weight part of the total amount of a radical polymerization initiator (a2).

As described above, in the present invention, in the presence of a radical polymerization initiator (a2) having a dehydrogenation action, a radical is generated in the methylene group of the radically polymerizable compound (a1) having an active methylene group, such as methylene group and PVA. The hydroxyl group of the polarizer reacts to form a covalent bond. Therefore, in order to generate a radical in the methylene group of the radically polymerizable compound (a1) having an active methylene group and to sufficiently form such a covalent bond, when the total amount of the curable component is 100% by weight, the radical polymerizability having an active methylene group It is preferable to contain 1-50 weight% of compound (a1), and it is more preferable to contain 3-30 weight% further. In order to sufficiently improve water resistance and improve adhesion in a non-dried state, the radical polymerizable compound (a1) having an active methylene group is preferably set to 1% by weight or more. On the other hand, when it exceeds 50% by weight, a curing failure of the adhesive layer may occur. In addition, the radical polymerization initiator (a2) having a dehydrogenation function is preferably contained in an amount of 0.1 to 10 parts by weight, and more preferably 0.3 to 9 parts by weight, based on 100 parts by weight of the total amount of the curable component. In order to sufficiently advance the dehydrogenation reaction, it is preferable to use 0.1 parts by weight or more of the radical polymerization initiator (a2). On the other hand, when it exceeds 10 parts by weight, it may not be completely dissolved in the adhesive.

≪Thermal polymerization initiator≫

As the thermal polymerization initiator, it is preferable that the polymerization does not start due to thermal cleavage during formation of the adhesive layer. For example, as a thermal polymerization initiator, it is preferable that the 10-hour half-life temperature is 65 degreeC or more, and further 75-90 degreeC. In addition, the half-life of is an index showing the decomposition rate of the polymerization initiator, and refers to the time until the residual amount of the polymerization initiator becomes half. Regarding the decomposition temperature for obtaining the half-life at an arbitrary time and the half-life at an arbitrary temperature are described in the manufacturer's catalog, for example, Nippon Oil Co., Ltd.'s ``Organic Peroxide Catalog 9th Edition (May 2003 )”, etc.

As a thermal polymerization initiator, for example, lauroyl peroxide (10 hour half-life temperature: 64°C), benzoyl peroxide (10 hour half-life temperature: 73°C), 1,1-bis(t-butylperoxy)-3, 3,5-trimethylcyclohexane (10 hour half-life temperature: 90°C), di(2-ethylhexyl)peroxydicarbonate (10 hour half-life temperature: 49°C), di(4-t-butylcyclohexyl)peroxydicarbonate , Di-sec-butylperoxydicarbonate (10 hour half-life temperature: 51°C), t-butylperoxyneodecanoate (10 hour half-life temperature: 48°C), t-hexylperoxypivalate, t-butylper Oxypivalate, dilauroyl peroxide (10 hour half-life temperature: 64°C), di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (10 Time half-life temperature: 66°C), di(4-methylbenzoyl)peroxide, dibenzoyl peroxide (10 hour half-life temperature: 73°C), t-butylperoxyisobutyrate (10 hour half-life temperature: 81°C), Organic peroxides, such as 1,1-di(t-hexylperoxy)cyclohexane, are mentioned.

In addition, as a thermal polymerization initiator, for example, 2,2'-azobisisobutyronitrile (10 hour half-life temperature: 67°C), 2,2'-azobis(2-methylbutyronitrile) (10 hours Azo compounds, such as half-life temperature: 67 degreeC) and 1,1-azobis-cyclohexane-1-carbonitrile (10 hour half-life temperature: 87 degreeC), are mentioned.

The blending amount of the thermal polymerization initiator is 0.01 to 20 parts by weight based on 100 parts by weight of the total amount of the curable component (radical polymerizable compound). It is preferable that the blending amount of the thermal polymerization initiator is further from 0.05 to 10 parts by weight, and further from 0.1 to 3 parts by weight.

<2: Cationic polymerization curable adhesive>

As the curable component of the cation polymerization curable adhesive, a compound having an epoxy group or an oxetanyl group can be mentioned. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used. As a preferred epoxy compound, a compound having at least two epoxy groups in the molecule and at least one aromatic ring (aromatic epoxy compound), or having at least two epoxy groups in the molecule, at least one of which is a neighbor constituting an alicyclic ring A compound (alicyclic epoxy compound) formed between the two carbon atoms described above can be exemplified.

<Photocationic polymerization initiator>

The cation polymerization curable adhesive contains the epoxy compound and oxetane compound described above as curable components, and both of them are cured by cation polymerization, and thus a photocationic polymerization initiator is blended. This photocationic polymerization initiator generates a cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of an epoxy group or an oxetanyl group.

<Other ingredients>

It is preferable that the curable adhesive according to the present invention contains the following components.

<Acrylic oligomer (A)>

The active energy ray-curable adhesive according to the present invention may contain, in addition to the curable component related to the radical polymerizable compound, an acrylic oligomer (A) obtained by polymerizing a (meth)acryl monomer. By containing the acrylic oligomer (A) in the active energy ray-curable adhesive, curing shrinkage when irradiating and curing the adhesive with active energy rays is reduced, and the interfacial stress between the adhesive and the adherend such as a polarizer and transparent protective film is reduced. can do. As a result, it is possible to suppress a decrease in adhesion between the adhesive layer and the adherend. In order to sufficiently suppress curing shrinkage of the cured product layer (adhesive layer), the content of the acrylic oligomer (A) is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, based on 100 parts by weight of the total amount of the curable component. desirable. If the content of the acrylic oligomer (A) in the adhesive is too large, the decrease in the reaction rate when the adhesive is irradiated with an active energy ray is severe, resulting in poor curing in some cases. On the other hand, with respect to 100 parts by weight of the total amount of the curable component, it is preferable to contain 3 parts by weight or more of the acrylic oligomer (A), and more preferably 5 parts by weight or more.

Since the active energy ray-curable adhesive is preferably of low viscosity in consideration of workability and uniformity at the time of application, the acrylic oligomer (A) obtained by polymerizing a (meth)acrylic monomer is also preferably of low viscosity. As an acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer, a weight average molecular weight (Mw) of 15000 or less, more preferably 10000 or less, and particularly preferably 5000 or less. On the other hand, in order to sufficiently suppress curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer (A) is preferably 500 or more, more preferably 1000 or more, and particularly preferably 1500 or more. . As the (meth)acrylic monomer constituting the acrylic oligomer (A), specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) Acrylate, 2-methyl-2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, S-butyl (meth)acrylate, t-butyl (meth)acrylic Rate, n-pentyl (meth)acrylate, t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, Cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, N-octadecyl (meth)acrylate, etc. Of (meth)acrylic acid (carbon number 1 to 20) alkyl esters, and, for example, cycloalkyl (meth)acrylate (eg, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.) , Aralkyl (meth) acrylate (eg, benzyl (meth) acrylate, etc.), polycyclic (meth) acrylate (eg, 2-isobornyl (meth) acrylate, 2-norbornyl Methyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylic acid Esters (for example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), alkoxy group or (Meth)acrylic acid esters containing a phenoxy group (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (Meth)acrylate, ethylcarbitol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic acid esters (eg glycidyl (meth)acrylate, etc.), Halogen-containing (meth)acrylic acid esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluoro Rodecyl (meth)acrylate, etc.), alkylaminoalkyl (meth)acrylate (eg, dimethylaminoethyl (meth)acrylate), and the like. These (meth)acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer (A) include "ARUFON" by Toa Synthetic Company, "Actflow" by Soken Chemical Company, and "JONCRYL" by BASF Japan. Among the acrylic oligomers (A) formed by polymerizing (meth)acrylic monomers, those having a high logPow value are preferred. The acrylic oligomer (A) is contained in a component in the calculation of the logPow value of the curable adhesive for polarizing films. In the calculation of the logPow value, the number of moles of the component related to the acrylic oligomer (A) is the number of moles converted to the (meth)acrylic monomer constituting the acrylic oligomer (A). The logPow value of the acrylic oligomer (A) formed by polymerizing a (meth)acrylic monomer is preferably 2 or more, more preferably 3 or more, and most preferably 4 or more.

<mine generator (B)>

In the active energy ray-curable adhesive, it may contain a photoacid generator (B). When the active energy ray-curable adhesive contains a photoacid generator, the water resistance and durability of the adhesive layer can be dramatically improved compared to the case where the photoacid generator is not contained. The photoacid generator (B) can be represented by the following general formula (3).

General Formula (3)

[Formula 3]

(Where, L ⁺ is representative of any of the onium cation addition, X ^{-. _{Is, PF6 6 -, SbF 6 -}} , AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dt O carbamate anion, SCN ^- represents a counter anion selected from the group consisting of a).

As the structure of the onium cation preferable as the onium cation L ⁺ constituting the general formula (3), onium cation selected from the following general formulas (4) to (12) can be mentioned.

General Formula (4)

[Formula 4]

General Formula (5)

[Formula 5]

General Formula (6)

[Formula 6]

General formula (7)

[Formula 7]

General Formula (8)

[Formula 8]

General Formula (9)

[Formula 9]

General Formula (10)

[Formula 10]

General Formula (11)

[Formula 11]

General Formula (12)

[Formula 12]

(In the general formulas (4)-(12), provided that R ¹ , R ² and R ³ are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted Substituted aryl group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted alkoxyl group, substituted or unsubstituted aryloxy group, substituted or unsubstituted heterocyclic oxy group, substituted or unsubstituted acyl group, substituted Or an unsubstituted carbonyloxy group, a substituted or unsubstituted oxycarbonyl group, or a group selected from a halogen atom, R ⁴ represents the same group as the group described in R ¹ , R ² and R ^3. R ⁵ represents a substituted Or an unsubstituted alkyl group or a substituted or unsubstituted alkylthio group R ⁶ and R ⁷ each independently represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxyl group R is a halogen atom, Hydroxyl group, carboxyl group, mercapto group, cyano group, nitro group, substituted or unsubstituted carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted alkenyl group, substituted or unsubstituted aryl group, substituted or unsubstituted A heterocyclic group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heterocyclic oxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group, Represents either a substituted or unsubstituted heterocyclic thi group, a substituted or unsubstituted acyl group, a substituted or unsubstituted carbonyloxy group, and a substituted or unsubstituted oxycarbonyl group Ar ⁴ and Ar ⁵ are substituted or unsubstituted. Represents either a substituted aryl group or a substituted or unsubstituted heterocyclic group, X represents an oxygen or sulfur atom, i represents an integer of 0-5, j represents an integer of 0-4, k represents It represents an integer of 0 to 3. In addition, adjacent Rs, Ar ⁴ and Ar ⁵ , R ² and R ³ , R ² and R ⁴ , R ³ and R ⁴ , R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁴ , R ¹ and R, or R ¹ and R ⁵ may be cyclic structures bonded to each other.)

Onium cation (sulfonium cation) corresponding to general formula (4):

Dimethylphenylsulfonium, dimethyl(o-fluorophenyl)sulfonium, dimethyl(m-chlorophenyl)sulfonium, dimethyl(p-bromophenyl)sulfonium, dimethyl(p-cyanophenyl)sulfonium, dimethyl( m-nitrophenyl)sulfonium, dimethyl(2,4,6-tribromophenyl)sulfonium, dimethyl(pentafluorophenyl)sulfonium, dimethyl(p-(trifluoromethyl)phenyl)sulfonium, dimethyl (p-hydroxyphenyl)sulfonium, dimethyl(p-mercaptophenyl)sulfonium, dimethyl(p-methylsulfinylphenyl)sulfonium, dimethyl(p-methylsulfonylphenyl)sulfonium, dimethyl(o-acetyl) Phenyl) sulfonium, dimethyl (o-benzoylphenyl) sulfonium, dimethyl (p-methylphenyl) sulfonium, dimethyl (p-isopropylphenyl) sulfonium, dimethyl (p-octadecylphenyl) sulfonium, dimethyl (p- Cyclohexylphenyl)sulfonium, dimethyl(p-methoxyphenyl)sulfonium, dimethyl(o-methoxycarbonylphenyl)sulfonium, dimethyl(p-phenylsulfanylphenyl)sulfonium, (7-methoxy-2 -Oxo-2H-kuromen-4-yl)dimethylsulfonium, (4-methoxynaphthalen-1-yl)dimethylsulfonium, dimethyl(p-isopropoxycarbonylphenyl)sulfonium, dimethyl(2-naph) Tyl) sulfonium, dimethyl (9-anthryl) sulfonium, diethylphenylsulfonium, methylethylphenylsulfonium, methyldiphenylsulfonium, triphenylsulfonium, diisopropylphenylsulfonium, diphenyl (4- Phenylsulfanyl-phenyl)-sulfonium, 4,4'-bis(diphenylsulfonium)diphenylsulfide, 4,4'-bis[di[(4-(2-hydroxy-ethoxy)-phenyl) )]Sulfonium]]diphenylsulfide, 4,4'-bis(diphenylsulfonium)biphenylene, diphenyl(o-fluorophenyl)sulfonium, diphenyl(m-chlorophenyl)sulfonium, Diphenyl (p-bromophenyl) sulfonium, diphenyl (p-cyanophenyl) sulfonium, diphenyl (m-nitrophenyl) sulfonium, diphenyl (2,4,6-tribromophenyl) alcohol Phonium, diphenyl (pentafluorophenyl) sulfonium, diphenyl (p-(trifluoromethyl) phenyl) sulfonium, diphenyl (p-hydroxyphenyl) sulfonium, diphenyl (p-mercaptophenyl) Sulfonium, diphenyl (p-methylsulfinylphenyl) sulfonium, diphenyl (p-methylsulfonylphenyl) sulfonium, diphenyl (o-acetylphenyl) sulfonium, diphenyl (o-benzoylphenyl) sulfonium , Diphenyl (p-methylphenyl) sulfonium, diphenyl (p-isopropylphenyl) sulfonium, diphenyl (p-octadecylphenyl) sulfonium, diphenyl (p-cyclohexylphenyl) sulfo Nium, diphenyl (p-methoxyphenyl) sulfonium, diphenyl (o-methoxycarbonylphenyl) sulfonium, diphenyl (p-phenylsulfanylphenyl) sulfonium, (7-methoxy-2-oxo -2H-kuromen-4-yl) diphenylsulfonium, (4-methoxynaphthalen-1-yl) diphenylsulfonium, diphenyl (p-isopropoxycarbonylphenyl) sulfonium, diphenyl (2 -Naphthyl)sulfonium, diphenyl(9-anthryl)sulfonium, ethyldiphenylsulfonium, methylethyl(o-tolyl)sulfonium, methyldi(p-tolyl)sulfonium, tri(p-tolyl) Sulfonium, diisopropyl(4-phenylsulfanylphenyl)sulfonium, diphenyl(2-thienyl)sulfonium, diphenyl(2-furyl)sulfonium, diphenyl(9-ethyl-9Hcarbazole-3) -Il)sulfonium, etc. are mentioned, but are not limited to these.

Onium cation (sulfoxonium cation) corresponding to the general formula (5):

Dimethylphenylsulfoxonium, dimethyl(o-fluorophenyl)sulfoxonium, dimethyl(m-chlorophenyl)sulfoxonium, dimethyl(p-bromophenyl)sulfoxonium, dimethyl(p-cyanophenyl)sulfur Foxonium, dimethyl(m-nitrophenyl)sulfoxonium, dimethyl(2,4,6-tribromophenyl)sulfoxonium, dimethyl(pentafluorophenyl)sulfoxonium, dimethyl(p-(trifluoro Methyl)phenyl)sulfoxonium, dimethyl(p-hydroxyphenyl)sulfoxonium, dimethyl(p-mercaptophenyl)sulfoxonium, dimethyl(p-methylsulfinylphenyl)sulfoxonium, dimethyl(p-methyl Sulfonylphenyl)sulfoxonium, dimethyl(o-acetylphenyl)sulfoxonium, dimethyl(o-benzoylphenyl)sulfoxonium, dimethyl(p-methylphenyl)sulfoxonium, dimethyl(p-isopropylphenyl)sulfoxonium Nium, dimethyl (p-octadecylphenyl) sulfoxonium, dimethyl (p-cyclohexylphenyl) sulfoxonium, dimethyl (p-methoxyphenyl) sulfoxonium, dimethyl (o-methoxycarbonylphenyl) sulfoxy Nium, dimethyl(p-phenylsulfanylphenyl)sulfoxonium, (7-methoxy-2-oxo-2H-kuromen-4-yl)dimethylsulfoxonium, (4-methoxynaphthalen-1-yl) Dimethylsulfoxonium, dimethyl(p-isopropoxycarbonylphenyl)sulfoxonium, dimethyl(2-naphthyl)sulfoxonium, dimethyl(9-anthryl)sulfoxonium, diethylphenylsulfoxonium, methyl Ethylphenylsulfoxonium, methyldiphenylsulfoxonium, triphenylsulfoxonium, diisopropylphenylsulfoxonium, diphenyl(4-phenylsulfanyl-phenyl)-sulfoxonium, 4,4'-bis( Diphenylsulfoxonium)diphenylsulfide, 4,4'-bis[di[(4-(2-hydroxy-ethoxy)-phenyl)]sulfoxonium]diphenylsulfide, 4,4'- Bis(diphenylsulfoxonium)biphenylene, diphenyl(o-fluorophenyl)sulfoxonium, diphenyl(m-chlorophenyl)sulfoxonium, diphenyl(p-bromophenyl)sulfoxonium, Diphenyl (p-cyanophenyl) sulfoxonium, diphenyl (m-nitrophenyl) sulfoxonium, diphenyl (2,4,6-tribromophenyl) sulfoxonium, diphenyl (pentafluorophenyl) ) Sulfoxonium, diphenyl (p-(trifluoromethyl) phenyl) sulfoxonium, diphenyl (p-hydroxyphenyl) sulfoxonium, diphenyl (p-mercaptophenyl) sulfoxonium, diphenyl (p-methylsulfinylphenyl) sulfoxonium, diphenyl (p-methylsulfonylphenyl) sulfoxonium, diphenyl (o-acetylphenyl) sulfoxonium, diphenyl (o-benzoylphenyl) sulfoxonium, Diphenyl (p-methylphenyl) sulfoxonium, diphenyl (p-isopropylphenyl) sulfoxonium, diphenyl (p-octadecylphenyl) sulfoxonium, diphenyl (p-cyclohexylphenyl) sulfoxonium, diphenyl (p-methoxyphenyl) sulfoxonium, Diphenyl (o-methoxycarbonylphenyl) sulfoxonium, diphenyl (p-phenylsulfanylphenyl) sulfoxonium, (7-methoxy-2-oxo-2H-chromen-4-yl) diphenyl Sulfoxonium, (4-methoxynaphthalen-1-yl)diphenylsulfoxonium, diphenyl(p-isopropoxycarbonylphenyl)sulfoxonium, diphenyl(2-naphthyl)sulfoxonium, di Phenyl (9-anthryl) sulfoxonium, ethyldiphenyl sulfoxonium, methylethyl (o-tolyl) sulfoxonium, methyldi (p-tolyl) sulfoxonium, tri (p-tolyl) sulfoxonium, Diisopropyl(4-phenylsulfanylphenyl)sulfoxonium, diphenyl(2-thienyl)sulfoxonium, diphenyl(2-furyl)sulfoxonium, diphenyl(9-ethyl-9Hcarbazole-3) -Il)sulfoxonium, etc. are mentioned, but are not limited to these.

Onium cation (phosphonium cation) corresponding to the general formula (6):

Examples of phosphonium cation:

Trimethylphenylphosphonium, triethylphenylphosphonium, tetraphenylphosphonium, triphenyl(p-fluorophenyl)phosphonium, triphenyl(o-chlorophenyl)phosphonium, triphenyl(m-bromophenyl)phosphonium , Triphenyl (p-cyanophenyl) phosphonium, triphenyl (m-nitrophenyl) phosphonium, triphenyl (p-phenylsulfanylphenyl) phosphonium, (7-methoxy-2-oxo-2H-kuro Men-4-yl) triphenylphosphonium, triphenyl (o-hydroxyphenyl) phosphonium, triphenyl (o-acetylphenyl) phosphonium, triphenyl (m-benzoylphenyl) phosphonium, triphenyl (p- Methylphenyl)phosphonium, triphenyl(p-isopropoxyphenyl)phosphonium, triphenyl(o-methoxycarbonylphenyl)phosphonium, triphenyl(1-naphthyl)phosphonium, triphenyl(9-anthryl) ) Phosphonium, triphenyl (2-thienyl) phosphonium, triphenyl (2-furyl) phosphonium, triphenyl (9-ethyl-9H carbazol-3-yl) phosphonium, etc. are mentioned. It is not limited.

Onium cation (pyridinium cation) corresponding to general formula (7):

Examples of pyridinium cation:

N-phenylpyridinium, N-(o-chlorophenyl)pyridinium, N-(m-chlorophenyl)pyridinium, N-(p-cyanophenyl)pyridinium, N-(o-nitrophenyl)pyridinium , N-(p-acetylphenyl)pyridinium, N-(p-isopropylphenyl)pyridinium, N-(p-octadecyloxyphenyl)pyridinium, N-(p-methoxycarbonylphenyl)pyridinium , N-(9-anthryl)pyridinium, 2-chloro-1-phenylpyridinium, 2-cyano-1-phenylpyridinium, 2-methyl-1-phenylpyridinium, 2-vinyl-1-phenyl Pyridinium, 2-phenyl-1-phenylpyridinium, 1,2-diphenylpyridinium, 2-methoxy-1-phenylpyridinium, 2-phenoxy-1-phenylpyridinium, 2-acetyl-1- (p-tolyl)pyridinium, 2-methoxycarbonyl-1-(p-tolyl)pyridinium, 3-fluoro-1-naphthylpyridinium, 4-methyl-1-(2-furyl)pyridinium , N-methylpyridinium, N-ethylpyridinium, and the like, but are not limited thereto.

Onium cation (quinolinium cation) corresponding to the general formula (8):

Examples of quinolinium cation:

N-methylquinolinium, N-ethylquinolinium, N-phenylquinolinium, N-naphthylquinolinium, N-(o-chlorophenyl)quinolinium, N-(m-chlorophenyl)quinoli Nium, N-(p-cyanophenyl)quinolinium, N-(o-nitrophenyl)quinolinium, N-(p-acetylphenyl)quinolinium, N-(p-isopropylphenyl)quinoli Nium, N-(p-octadecyloxyphenyl)quinolinium, N-(p-methoxycarbonylphenyl)quinolinium, N-(9-anthryl)quinolinium, 2-chloro-1-phenyl Quinolinium, 2-cyano-1-phenylquinolinium, 2-methyl-1-phenylquinolinium, 2-vinyl-1-phenylquinolinium, 2-phenyl-1-phenylquinolinium, 1 ,2-diphenylquinolinium, 2-methoxy-1-phenylquinolinium, 2-phenoxy-1-phenylquinolinium, 2-acetyl-1-phenylquinolinium, 2-methoxycarbonyl -1-phenylquinolinium, 3-fluoro-1-phenylquinolinium, 4-methyl-1-phenylquinolinium, 2-methoxy-1-(p-tolyl)quinolinium, 2-phenoxy Cy-1-(2-furyl)quinolinium, 2-acetyl-1-(2-thienyl)quinolinium, 2-methoxycarbonyl-1-methylquinolinium, 3-fluoro-1- Ethylquinolinium, 4-methyl-1-isopropylquinolinium, and the like, but are not limited thereto.

Onium cation (isoquinolinium cation) corresponding to the general formula (9):

Examples of isoquinolinium cation:

N-phenylisoquinolinium, N-methylisoquinolinium, N-ethylisoquinolinium, N-(o-chlorophenyl)isoquinolinium, N-(m-chlorophenyl)isoquinolinium, N-(p-cyanophenyl)isoquinolinium, N-(o-nitrophenyl)isoquinolinium, N-(p-acetylphenyl)isoquinolinium, N-(p-isopropylphenyl)iso Quinolinium, N-(p-octadecyloxyphenyl)isoquinolinium, N-(p-methoxycarbonylphenyl)isoquinolinium, N-(9-anthryl)isoquinolinium, 1, 2-diphenylisoquinolinium, N-(2-furyl)isoquinolinium, N-(2-thienyl)isoquinolinium, N-naphthylisoquinolinium, etc. are mentioned. It is not limited.

Onium cation (benzoxazolium cation, benzothiazolium cation) corresponding to the general formula (10):

Examples of benzoxazolium cation:

N-methylbenzooxazolium, N-ethylbenzooxazolium, N-naphthylbenzooxazolium, N-phenylbenzooxazolium, N-(p-fluorophenyl)benzooxazolium, N-(p-chlorophenyl) Benzooxazolium, N-(p-cyanophenyl)benzoxazolium, N-(o-methoxycarbonylphenyl)benzoxazolium, N-(2-furyl)benzooxazolium, N-(o-fluoro Phenyl) benzoxazolium, N-(p-cyanophenyl) benzoxazolium, N-(m-nitrophenyl) benzoxazolium, N-(p-isopropoxycarbonylphenyl) benzoxazolium, N-( 2-thienyl)benzoxazolium, N-(m-carboxyphenyl)benzoxazolium, 2-mercapto-3-phenylbenzooxazolium, 2-methyl-3-phenylbenzooxazolium, 2-methylthio-3 -(4-phenylsulfanylphenyl)benzoxazolium, 6-hydroxy-3-(p-tolyl)benzooxazolium, 7-mercapto-3-phenylbenzooxazolium, 4,5-difluoro-3 -Ethyl benzoxazolium etc. are mentioned, but it is not limited to these.

Examples of benzothiazolium cation:

N-methylbenzothiazolium, N-ethylbenzothiazolium, N-phenylbenzothiazolium, N-(1-naphthyl)benzothiazolium, N-(p-fluorophenyl)benzothiazolium, N-(p -Chlorophenyl)benzothiazolium, N-(p-cyanophenyl)benzothiazolium, N-(o-methoxycarbonylphenyl)benzothiazolium, N-(p-tolyl)benzothiazolium, N-( o-fluorophenyl)benzothiazolium, N-(m-nitrophenyl)benzothiazolium, N-(p-isopropoxycarbonylphenyl)benzothiazolium, N-(2-furyl)benzothiazolium, N -(4-methylthiophenyl)benzothiazolium, N-(4-phenylsulfanylphenyl)benzothiazolium, N-(2-naphthyl)benzothiazolium, N-(m-carboxyphenyl)benzothiazolium, 2-mercapto-3-phenylbenzothiazolium, 2-methyl-3-phenylbenzothiazolium, 2-methylthio-3-phenylbenzothiazolium, 6-hydroxy-3-phenylbenzothiazolium, 7-mer Capto-3-phenylbenzothiazolium, 4,5-difluoro-3-phenylbenzothiazolium, etc. may be mentioned, but the present invention is not limited thereto.

Onium cation (furyl or thienyliodonium cation) corresponding to the general formula (11):

Difuryliodonium, dithienyliodonium, bis(4,5-dimethyl-2-furyl)iodonium, bis(5-chloro-2-thienyl)iodonium, bis(5-cyano-2-furyl) ) Iodonium, bis(5-nitro-2-thienyl)iodonium, bis(5-acetyl-2-furyl)iodonium, bis(5-carboxy-2-thienyl)iodonium, bis(5-me Toxycarbonyl-2-furyl)iodonium, bis(5-phenyl-2-furyl)iodonium, bis(5-(p-methoxyphenyl)-2-thienyl)iodonium, bis(5-vinyl- 2-furyl)iodonium, bis(5-ethynyl-2-thienyl)iodonium, bis(5-cyclohexyl-2-furyl)iodonium, bis(5-hydroxy-2-thienyl)iodonium , Bis(5-phenoxy-2-furyl)iodonium, bis(5-mercapto-2-thienyl)iodonium, bis(5-butylthio-2-thienyl)iodonium, bis(5-phenyl Thio-2-thienyl)iodonium, etc. are mentioned, but it is not limited to these.

Onium cation (diaryliodonium cation) corresponding to the general formula (12):

Diphenyliodonium, bis(p-tolyl)iodonium, bis(p-octylphenyl)iodonium, bis(p-octadecylphenyl)iodonium, bis(p-octyloxyphenyl)iodonium, bis(p- Octadecyloxyphenyl) iodonium, phenyl (p-octadecyloxyphenyl) iodonium, 4-isopropyl-4'-methyldiphenyliodonium, (4-isobutylphenyl)-p-tolyliodonium, bis( 1-naphthyl)iodonium, bis(4-phenylsulfanylphenyl)iodonium, phenyl(6-benzoyl-9-ethyl-9H-carbazol-3-yl)iodonium, (7-methoxy-2- Oxo-2H-chromen-3-yl)-4'-isopropylphenyliodonium, and the like, but are not limited thereto.

Next, the counter anion X ^- in General Formula (3) will be described.

The counter anion X ^- in General Formula (3) is not particularly limited in principle, but a non-nucleophilic anion is preferable. In the case where the counter anion X ^- is a non-nucleophilic anion, it is difficult to cause a nucleophilic reaction in the cation coexisting in the molecule or various materials used in combination. As a result, the photoacid generator itself represented by the general formula (2) It is possible to improve the stability over time of the adhesive using it. The non-nucleophilic anion here refers to an anion having a low ability to cause a nucleophilic reaction. Thus as anionic such, PF ₆ ^-, and the like _{^{-, SbF 6 -, AsF 6}} -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dithiocarbamate anion, SCN.

Among the above exemplified anion, the counter anion X in the general formula ⁽³⁾ as especially preferable examples are, PF ₆ ^-, SbF ₆ ^- and AsF ₆ ^- a can be mentioned, and particularly preferably, PF ₆ ^-, SbF ₆ ^- is mentioned.

Thus, the specific examples preferred onium salts that make up the photo-acid generator (B), the structure of the embodiment and PF ₆ of onium represented by the formula (3) to Formula (12) in the above-exemplified cationic ^-, SbF ₆ ^{-, _{AsF 6 -, SbCl 6 -,}} BiCl 5 -, SnCl 6 -, ClO 4 -, dithiocarbamate anion, SCN ^- is composed of an onium salt to anion is selected from the.

Specifically, "Syracure UVI-6992", "Syracure UVI-6974" (above, manufactured by Dow Chemical Nippon Co., Ltd.), "Adeka Optomer SP150", "Adeka Optomer SP152", "Ah Deca Optomer SP170", "Adeka Optomer SP172" (above, manufactured by ADEKA Co., Ltd.), "IRGACURE250" (manufactured by Chiba Specialty Chemicals, Inc.), "CI-5102", "CI-2855" (above, manufactured by Nippon Soda Corporation) ), ``San-Aid SI-60L'', ``San-Aid SI-80L'', ``San-Aid SI-100L'', ``San-Aid SI-110L'', ``San-Aid SI-180L'' (above, manufactured by Sanshin Chemical Co. CPI-100P", "CPI-100A" (above, manufactured by San-Apro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", " WPI-054", "WPI-055", "WPAG-281", "WPAG-567", "WPAG-596" (above, manufactured by Wako Junyaku Corporation) can be mentioned as preferred specific examples of the photoacid generator (B). have.

The content of the photoacid generator (B) is 10 parts by weight or less, preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and 0.1 to 3 parts by weight based on 100 parts by weight of the total amount of the curable component. It is particularly preferred to be denied.

<Compound (C) containing either an alkoxy group or an epoxy group>

In the active energy ray-curable adhesive, a compound (C) containing either an alkoxy group or an epoxy group may be contained. For example, in the relationship with the hydroxyl group of the PVA-based polarizer, the condensation reaction of the alkoxy group and the hydroxyl group proceeds in the compound (C1) containing an alkoxy group, and the addition reaction of the epoxy group and the hydroxyl group proceeds in the compound (C2) containing an epoxy group. It advances, and stronger adhesiveness can be provided to an active energy ray-curable adhesive. In the case of using the compound (C2) containing an epoxy group, a secondary hydroxyl group is generated after the reaction due to the addition reaction of the epoxy group and the hydroxyl group, and there is a possibility that the bulk absorption rate of the present invention may be increased, the compound having an alkoxy group (C1 It is more preferable to use ). That is, by laminating a polarizer and a transparent protective film via an active energy ray-curable adhesive containing a photoacid generator (B) and a compound (C1) having an alkoxy group, and irradiating an active energy ray, from the photoacid generator (B) With the generated acid, the alkoxy group of the compound (C1) having an alkoxy group and the hydroxyl group of the polarizer are condensed to react, and good adhesion between the polarizer and the transparent protective film is expressed. Further, an adhesive layer having a lower water absorption rate can be formed by the condensation reaction between the compounds (C1) having an alkoxy group, and optical durability in a harsh environment under high temperature and high humidity can be satisfied.

In the active energy ray-curable adhesive, the compound (C) containing either an alkoxy group or an epoxy group may be used alone or in combination of a plurality of them. In addition, the compound (C) containing either an alkoxy group or an epoxy group may be used in combination with the compound (C1) containing an alkoxy group and the compound (C2) containing an epoxy group. In addition, the compound (C) containing either an alkoxy group or an epoxy group can be used in combination with or without a photoacid generator (B), but promotes the reaction of the hydroxyl group of the PVA-based polarizer with the alkoxy group and the epoxy group. From the viewpoint of doing so, it is preferable to use the compound (C) containing either an alkoxy group or an epoxy group in combination with a photoacid generator (B).

(Compound (C1) having an alkoxy group)

The compound (C1) having an alkoxy group in the molecule is not particularly limited as long as it has one or more alkoxyl groups in the molecule, and known compounds can be used. For example, as a substituent, the general formula: -(CH ₂ ) _n -OR (in the formula, n is an integer of 1 to 3, and R represents an alkyl group having 1 to 4 carbon atoms or H. In the formula, R is a methyl group. It is preferable that it is.) and the compound which has an alkoxy group represented by is mentioned. Specifically, for example, alkoxy group-containing radical polymerizable compounds such as alkoxyalkyl (meth)acrylate and alkoxyalkyl (meth)acrylamide, melamine compounds such as methylolmelamine and alkoxymethylated melamine, amino resins and silane couples Ringer is mentioned. As specific examples of the alkoxy group-containing radical polymerizable compound, Wasma 2MA, Wasma 3MA, Wasma IBM, N-isobutoxymethylacrylamide, Wasma EMA, N-MAM-PC, MM90, Wasma manufactured by Cassano Kosan Corporation A etc. are mentioned. As a specific example of a melamine compound, M-3, MK, M-6, M-100, MC, etc. of the Sumitex resin series manufactured by Sumitomo Chemical Co., Ltd., and Nikarakku MW-30, MW-100LM, MX- manufactured by Sanwa Chemical Co., Ltd. 750LM, MX-280, MX-270, etc. can be illustrated. Among these, it is preferable to use Wasma 2MA, N-MAM-PC, MX-750LM or the like from the viewpoint of reactivity. In addition, when calculating the glass transition temperature Tg of the adhesive layer, the compound having an alkoxyl group and the polymer (C1) are not included in the calculation.

(Compound having an epoxy group (C2))

As the compound (C2) having an epoxy group, a compound having one or more epoxy groups in the molecule or a polymer (epoxy resin) having two or more epoxy groups in the molecule can be used. In the case of using a polymer (epoxy resin), a compound having two or more functional groups having reactivity with an epoxy group may be used in combination. Here, the functional group having reactivity with the epoxy group includes, for example, a carboxyl group, a phenolic hydroxyl group, a mercapto group, and a primary or secondary aromatic amino group. It is particularly preferable to have two or more of these functional groups in one molecule in consideration of three-dimensional curability.

Examples of polymers having one or more epoxy groups in the molecule include epoxy resins, bisphenol A type epoxy resins derived from bisphenol A and epichlorhydrin, bisphenol F derived from bisphenol F and epichlorhydrin. Type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy Resin, hydroquinone type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, polyfunctional type epoxy resin such as trifunctional type epoxy resin or tetrafunctional type epoxy resin, glycidyl ester type epoxy resin , Glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain type epoxy resin, and the like, and these epoxy resins may be halogenated or hydrogenated. As a commercially available epoxy resin product, for example, JER Coat 828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000, manufactured by Japan Epoxy Resin Co., Ltd., Epiclon 830 manufactured by DIC Corporation. , EXA835LV, HP4032D, HP820, ADEKA Co., Ltd. EP4100 series, EP4000 series, EPU series, Daicel Chemical Co., Ltd. Celoxide series (2021, 2021P, 2083, 2085, 3000, etc.), Eporide series, EHPE series, Shinnit YD series, YDF series, YDCN series, YDB series, phenoxy resins (polyhydroxypolyether synthesized from bisphenols and epichlorhydrin, having epoxy groups at both ends; YP series, etc.), manufactured by Tetsu Chemical Co., Ltd., Nagase Chem Denacol series manufactured by Tex Corporation, Epolite series manufactured by Kyoeisha Chemical Company, etc. can be mentioned, but the present invention is not limited thereto. These epoxy resins may use 2 or more types together. In addition, when calculating the glass transition temperature Tg of the adhesive layer, the compound (C2) having an epoxy group is not included in the calculation.

The compounding amount of the compound (C) containing either an alkoxy group or an epoxy group is usually 30 parts by weight or less, based on 100 parts by weight of the total amount of the curable component, and the compound (C) in the active energy ray-curable adhesive When the content is too large, the adhesiveness decreases and the impact resistance to the drop test may deteriorate. It is more preferable that the content of the compound (C) in the active energy ray-curable adhesive is 20 parts by weight or less. On the other hand, from the viewpoint of water resistance, in the active energy ray-curable adhesive, it is preferable to contain 2 parts by weight or more of the compound (C), and more preferably 5 parts by weight or more.

<Isocyanate compound (D)>

The active energy ray-curable adhesive of the present invention may contain an isocyanate compound (D). The isocyanate compound (D) is a compound having at least one isocyanate group in a molecule. When the active energy ray-curable adhesive contains an isocyanate compound (D), strong adhesiveness and water resistance can be imparted by a polarizing film by interacting with a hydroxyl group and an isocyanate group on the surface of the polarizer. In addition, when the active energy ray-curable adhesive contains, as a radical polymerizable compound, an N-hydroxyalkyl group-containing (meth)acrylamide derivative, when the content of the N-hydroxyalkyl group-containing (meth)acrylamide derivative increases, Since the hydroxyl group is contained in the adhesive layer, the bulk absorption rate tends to increase, and as a result, the optical durability in a harsh humid environment tends to decrease. By using an N-hydroxyalkyl group-containing (meth)acrylamide derivative and a compound having an isocyanate group together, the hydroxyl group and the isocyanate group that do not contribute to the adhesion to the polarizer form a urethane bond, thereby reducing the bulk absorption rate while maintaining adhesion. I can.

As an isocyanate compound (D), a polyfunctional isocyanate compound, an active energy ray-curable isocyanate compound, etc. are mentioned. Examples of polyfunctional isocyanate compounds include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; cyclopentylene diisocyanate, cyclohexylene Alicyclic polyisocyanates such as diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate and hydrogenated xylene diisocyanate; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenyl And aromatic polyisocyanates such as methane diisocyanate and xylylene diisocyanate. As the isocyanate compound (D), for example, trimethylolpropane/tolylene diisocyanate adduct [Nippon Polyurethane Industrial Co., Ltd. product, brand name "Colonate L"], trimethylolpropane/hexamethylene diisocyanate adduct [Nippon Poly Urethane Industries Co., Ltd. product, brand name "Colonate HL"], brand name "Colonate HX" (Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane/xylylene diisocyanate adduct [Mitsui Chemicals Co., Ltd. product, brand name "Takenate 110N"] Commercial items such as etc. are also mentioned. Examples of the active energy ray-curable isocyanate compound (D) include isocyanates having a (meth)acryloyl group, and examples include Carens AOI (manufactured by Showa Electric Co., Ltd.) and Carens BEI (manufactured by Showa Electric Co., Ltd.). ), and commercial items such as Laromer LR9000 (manufactured by BASF).

The blending amount of the isocyanate compound (D) is usually 30 parts by weight or less with respect to 100 parts by weight of the total amount of the curable component, and if the content of the compound (D) in the active energy ray-curable adhesive bath is too large, the adhesiveness It may fall, and the impact resistance to a drop test may deteriorate. It is more preferable that the content of the compound (D) in the active energy ray-curable adhesive is 20 parts by weight or less. On the other hand, from the viewpoint of water resistance, it is preferable to contain 0.1 parts by weight or more of the compound (D) in the active energy ray-curable adhesive, and more preferably 1 part by weight or more.

<Silane coupling agent (E)>

In the case where the curable adhesive for polarizing film of the present invention is an active energy ray curable curable type, the silane coupling agent (E) is preferably an active energy ray curable compound, but provides the same water resistance even if it is not active energy ray curable. can do.

As a specific example of the silane coupling agent (E), as an active energy ray-curable compound, vinyl trichlorsilane, vinyl trimethoxysilane, vinyl triethoxysilane, 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldime Methoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane. .

Preferably, they are 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane.

As a specific example of a silane coupling agent which is not active energy ray curable, a silane coupling agent (E1) having an amino group is preferable. Specific examples of the silane coupling agent (E1) having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltri Ethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(2-(2-aminoethyl)aminoethyl)amino Propyltrimethoxysilane, γ-(6-aminohexyl)aminopropyltrimethoxysilane, 3-(N-ethylamino)-2-methylpropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane, γ -Ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, N -Cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl)aminomethyltrimethoxysilane, N,N'-bis [3-(trimethoxysilyl)propyl] amino group-containing silanes such as ethylenediamine; Ketimine types such as N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine Silanes are mentioned.

As the silane coupling agent (E1) having an amino group, only one type may be used, or a plurality of types may be used in combination. Among these, in order to ensure good adhesion, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl )-1-propanamine is preferred.

The blending amount of the silane coupling agent (E) is preferably in the range of 0.01 to 20 parts by weight, preferably 0.05 to 15 parts by weight, and more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the total amount of the curable component. This is because, in the case of a blending amount exceeding 20 parts by weight, the storage stability of the adhesive deteriorates, and in the case of less than 0.1 parts by weight, the effect of water-resistant adhesiveness is not sufficiently exhibited. In addition, when calculating the glass transition temperature Tg of the adhesive layer, the silane coupling agent (E) is not taken into account.

As specific examples of silane coupling agents other than those described above, which are not active energy ray-curable, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyl Trimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanate propyltriethoxysilane, imidazole silane, etc. are mentioned.

Also for the above photoacid generator (B), a compound (C) containing any one of an alkoxy group and an epoxy group, an isocyanate compound (D), and a silane coupling agent (E), the logPow value of each component is preferably 1 or more, More preferably, it is 2 or more. In addition, the photoacid generator (B) and the silane coupling agent (E) are not included in the component in the calculation of the logPow value of the curable adhesive for polarizing films. On the other hand, the compound (C) and the isocyanate compound (D) containing either an alkoxy group or an epoxy group are included in the components in the calculation of the logPow value of the curable adhesive for polarizing films.

<Additives other than the above>

Further, in the curable adhesive for polarizing films of the present invention, various additives can be blended as other optional components within a range that does not impair the object and effect of the present invention. Examples of such additives include polyamide, polyamideimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene-butadiene block copolymer, petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based oligomer, and silicone-based Polymers or oligomers such as oligomers and polysulfide-based oligomers; polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol; polymerization initiation aids; leveling agents; wettability improving agents; surfactants; Plasticizer; ultraviolet absorber; inorganic filler; pigment; dye, etc. are mentioned. Among various additives, those having a high logPow value are preferred. The logPow values of various additives are preferably 2 or more, more preferably 3 or more, and most preferably 4 or more. In addition, these additives are not included in the component in the calculation of the logPow value of the curable adhesive for polarizing films.

The above additives are usually 0 to 10 parts by weight, preferably 0 to 5 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component.

<Viscosity of adhesive>

The curable adhesive for polarizing films of the present invention contains the curable component, but the viscosity of the adhesive is preferably 100 cp or less at 25°C from the viewpoint of coatability. On the other hand, when the curable adhesive for polarizing films of the present invention exceeds 100 cp at 25°C, the temperature of the adhesive can be controlled at the time of application and adjusted to 100 cp or less for use. A more preferable range of the viscosity is 1 to 80 cp, most preferably 10 to 50 cp. The viscosity can be measured using an E-type viscometer TVE22LT manufactured by Toki Industries.

In addition, in the curable adhesive for polarizing films of the present invention, from the viewpoint of safety, it is preferable to use a material having low skin irritation as the curable component. Skin irritation can be judged by an index called P.I.I. P.I.I is widely used as indicating the degree of skin disorder and is measured by the Draise method. The measured value is expressed in the range of 0 to 8, and the smaller the value is, the lower the stimulus is judged, but the error of the measured value is large, so it is better to grasp it as a reference value. P.I.I is preferably 4 or less, more preferably 3 or less, and most preferably 2 or less.

<polarizing film>

In the polarizing film of the present invention, a transparent protective film is bonded to at least one side of a polarizer through an adhesive layer formed by a cured product layer of the curable adhesive for polarizing films. As mentioned above, the adhesive layer which is the said hardened|cured material layer is 10 weight% or less in bulk water absorption.

<Adhesive layer>

It is preferable to control the thickness of the adhesive layer formed by the curable adhesive to be 0.1 to 3 µm. The thickness of the adhesive layer is more preferably 0.3 to 2 µm, and further preferably 0.5 to 1.5 µm. It is preferable to set the thickness of the adhesive layer to 0.1 µm or more in order to suppress the occurrence of adhesion failure due to the cohesive force of the adhesive layer or occurrence of appearance defects (bubbles) during lamination. On the other hand, when the adhesive layer is thicker than 3 µm, there is a concern that the polarizing film cannot satisfy durability.

In addition, the curable adhesive is preferably selected so that the Tg of the adhesive layer thus formed is 60°C or higher, further preferably 70°C or higher, further 75°C or higher, further 100°C or higher, and further 120°C. It is preferable that it is above. On the other hand, when the Tg of the adhesive layer is too high, the flexibility of the polarizing film decreases, and therefore, the Tg of the adhesive layer is preferably set to 300°C or less, further to 240°C or less, and further to 180°C or less. Tg <glass transition temperature> is measured under the following measurement conditions using the dynamic viscoelasticity measuring apparatus RSAIII manufactured by TA Instruments.

Sample size: 10 mm wide, 30 mm long,

Clamp distance 20 mm,

Measurement mode: tension, frequency: 1 Hz, heating rate: 5 ℃/min

The dynamic viscoelasticity was measured and adopted as the peak top temperature Tg of tan δ.

In addition, it is preferable that the curable adhesive has a storage elastic modulus of the adhesive layer thus formed of 1.0×10 ⁶ Pa or more in a region of 70°C or less. Furthermore, it is more preferably 1.0 × 10 ⁷ Pa or more. The storage modulus of the adhesive layer affects the polarizer crack when a heat cycle (-40°C to 80°C, etc.) is applied to the polarizing film, and when the storage elastic modulus is low, the problem of polarizer cracking is likely to occur. The temperature range having a high storage modulus is more preferably 80°C or less, and most preferably 90°C or less. The storage modulus is measured under the same measurement conditions using a dynamic viscoelasticity measuring device RSAIII manufactured by TA Instruments at the same time as Tg <glass transition temperature>. The dynamic viscoelasticity was measured and the value of the storage modulus (E'') was adopted.

The polarizing film according to the present invention is a step of bonding a polarizer and a transparent protective film after applying a curable adhesive to the surface forming the adhesive layer of the polarizer and/or the surface forming the adhesive layer of the transparent protective film, and then, It has a step of forming an adhesive layer by curing a curable adhesive.

The polarizer and the transparent protective film may be subjected to a surface modification treatment before applying the curable adhesive. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

The method of applying the curable adhesive is appropriately selected depending on the viscosity of the curable adhesive and the desired thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater, and the like. In addition, for coating, a method such as a dipping method can be appropriately used.

The polarizer and the transparent protective film are bonded through the curable adhesive applied as described above. The bonding of the polarizer and the transparent protective film can be performed by a roll laminator or the like.

<hardening of adhesive>

The curable adhesive for polarizing films according to the present invention is used as an active energy ray-curable adhesive or a thermosetting adhesive. In the active energy ray-curable adhesive, it can be used in an electron beam curing type, an ultraviolet curing type, or a visible ray curing type. In the aspect of the curable adhesive, from the viewpoint of productivity, an active energy ray-curable adhesive is preferable to a thermosetting adhesive, and as an active energy ray-curable adhesive, a visible ray-curable adhesive is preferable from the viewpoint of productivity.

≪Active energy ray curing type≫

In the active energy ray-curable adhesive, after bonding the polarizer and the transparent protective film, an active energy ray (electron ray, ultraviolet ray, visible ray, etc.) is irradiated to cure the active energy ray-curable adhesive to form an adhesive layer. The irradiation direction of an active energy ray (electron ray, ultraviolet ray, visible ray, etc.) can be irradiated from any suitable direction. Preferably, it irradiates from the transparent protective film side. When irradiated from the polarizer side, there is a fear that the polarizer is deteriorated by active energy rays (electron rays, ultraviolet rays, visible rays, etc.).

≪Electron beam hardening type≫

In the electron beam curing type, any suitable condition can be adopted as long as the irradiation condition of the electron beam is a condition capable of curing the active energy ray-curable adhesive. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, there is a risk that the electron beam does not reach the adhesive, resulting in insufficient curing. If the acceleration voltage exceeds 300 kV, the penetration force passing through the sample is too strong, causing damage to the transparent protective film or polarizer. There is concern. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive becomes insufficiently cured, and when it exceeds 100 kGy, damage is caused to the transparent protective film or polarizer, resulting in a decrease in mechanical strength or yellowing, thereby obtaining a predetermined optical property. none.

The electron beam irradiation is usually irradiated in an inert gas, but if necessary, it may be carried out in the atmosphere or under the condition of introducing a little oxygen. Depending on the material of the transparent protective film, by appropriately introducing oxygen, oxygen is partially inhibited on the surface of the transparent protective film to which the electron beam first touches, thereby preventing damage to the transparent protective film, and efficiently irradiating electron beams only with the adhesive. I can make it.

≪Ultraviolet ray curing type, visible ray curing type≫

In the method for producing a polarizing film according to the present invention, the active energy ray containing visible light in a wavelength range of 380 nm to 450 nm as an active energy ray, and in particular, an active energy ray in which the irradiation amount of visible light in a wavelength range of 380 nm to 450 nm is greatest It is preferable to use. In the case of using a transparent protective film (ultraviolet non-transmissive transparent protective film) that has an ultraviolet ray-curing type and a visible ray-curable type, light with a wavelength shorter than 380 nm is absorbed, so that light with a wavelength shorter than 380 nm is active energy. It does not reach the line-curable adhesive and does not contribute to the polymerization reaction. Further, light having a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, causing defects such as curls and wrinkles of the polarizing film. Therefore, in the case of employing an ultraviolet curing type or a visible ray curing type in the present invention, it is preferable to use a device that does not emit light with a wavelength shorter than 380 nm as an active energy ray generating device, and more specifically, a wavelength range of 380 It is preferable that the ratio of the integrated illuminance of -440 nm and the integrated illuminance of the wavelength range 250-370 nm is 100:0-100:50, and it is more preferable that it is 100:0-100:40. As the active energy ray according to the present invention, a gallium-encapsulated metal halide lamp and an LED light source emitting light in a wavelength range of 380 to 440 nm are preferable. Or, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or ultraviolet rays and visible light such as sunlight A light source including a may be used, and a band pass filter may be used to block ultraviolet rays with a wavelength shorter than 380 nm. In order to prevent curling of the polarizing film while improving the adhesion of the adhesive layer between the polarizer and the transparent protective film, a gallium-enclosed metal halide lamp is used, and a band pass filter capable of blocking light with a wavelength shorter than 380 nm is interposed. It is preferable to use the obtained active energy ray or an active energy ray having a wavelength of 405 nm obtained using an LED light source.

In the ultraviolet-curable or visible-ray-curable type, it is preferable to warm the active energy ray-curable adhesive (heating before irradiation) before irradiation with ultraviolet or visible light, and in that case, heating to 40°C or higher, and 50°C or higher It is more preferable to warm to. In addition, heating the active energy ray-curable adhesive after irradiation with ultraviolet rays or visible rays (heating after irradiation) is also preferable. In that case, heating to 40°C or higher is preferable, and heating to 50°C or higher is more preferable.

The active energy ray-curable adhesive according to the present invention can be preferably used in the case of forming an adhesive layer which bonds a polarizer and a transparent protective film having a light transmittance of less than 5% at a wavelength of 365 nm, particularly. Here, the active energy ray-curable adhesive according to the present invention contains the photopolymerization initiator of the above-described general formula (1), so that ultraviolet rays are irradiated over the transparent protective film having UV absorbing ability to cure the adhesive layer. . Therefore, also in the polarizing film which laminated|stacked the transparent protective film which has UV absorption ability on both surfaces of a polarizer, the adhesive layer can be hardened. However, naturally, also in the polarizing film which laminated|stacked the transparent protective film which does not have UV absorption ability, the adhesive layer can be hardened. In addition, the transparent protective film which has UV absorbing ability means the transparent protective film with the transmittance|permeability to light of 380 nm less than 10%.

As a method of imparting the UV absorbing ability to the transparent protective film, a method of including an ultraviolet absorber in the transparent protective film or a method of laminating a surface treatment layer containing an ultraviolet absorber on the surface of the transparent protective film can be mentioned.

Specific examples of the ultraviolet absorber include, for example, conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, triazine compounds, etc. Can be mentioned.

After bonding the polarizer and the transparent protective film, an active energy ray (electron ray, ultraviolet ray, visible ray, etc.) is irradiated, and the active energy ray-curable adhesive is cured to form an adhesive layer. The irradiation direction of an active energy ray (electron ray, ultraviolet ray, visible ray, etc.) can be irradiated from any suitable direction. Preferably, it irradiates from the transparent protective film side. When irradiated from the polarizer side, there is a fear that the polarizer is deteriorated by active energy rays (electron rays, ultraviolet rays, visible rays, etc.).

≪Thermosetting type≫

On the other hand, in a thermosetting adhesive, after bonding a polarizer and a transparent protective film, by heating, polymerization is started with a thermal polymerization initiator, and a cured product layer is formed. The heating temperature is set depending on the thermal polymerization initiator, but is about 60 to 200°C, preferably 80 to 150°C.

In the case of manufacturing the polarizing film according to the present invention in a continuous line, the line speed varies depending on the curing time of the adhesive, but is preferably 1 to 500 m/min, more preferably 5 to 300 m/min, further preferably Is 10 to 100 m/min. When the line speed is too small, productivity is insufficient, or damage to the transparent protective film is too great, and a polarizing film that can withstand durability tests or the like cannot be produced. When the line speed is too large, the curing of the adhesive is insufficient, and the target adhesiveness may not be obtained.

In addition, in the polarizing film of the present invention, a polarizer and a transparent protective film are bonded via an adhesive layer formed by the cured product layer of the active energy ray-curable adhesive, but an easily bonding layer is provided between the transparent protective film and the adhesive layer. Can be formed. The easy-to-adhesion layer can be formed of various resins having, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone type, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. . These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to the formation of the easily bonding layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, and a heat-resistant stabilizer may be used.

The easy-adhesion layer is usually formed in advance on a transparent protective film, and the easy-adhesion layer side of the said transparent protective film and a polarizer are bonded together by an adhesive layer. The formation of the easy-adhesion layer is performed by applying and drying a material for forming an easy-to-adhesion layer on a transparent protective film by a known technique. The material for forming the easy-to-adhesion layer is usually adjusted as a solution diluted to an appropriate concentration in consideration of the thickness after drying, smoothness of application, and the like. The thickness of the easily bonding layer after drying is preferably 0.01 to 5 µm, more preferably 0.02 to 2 µm, and still more preferably 0.05 to 1 µm. In addition, although a plurality of layers of the easily bonding layer can be formed, even in this case, it is preferable that the total thickness of the easily bonding layer is within the above range.

<polarizer>

The polarizer is not particularly limited, and various types of polarizers can be used. As a polarizer, for example, a dichroic material such as iodine or a dichroic dye is adsorbed to a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, an ethylene/vinyl acetate copolymer system partial saponification film, etc. Polyene-based oriented films, such as the thing which was made and uniaxially stretched, the dehydration-processed product of polyvinyl alcohol, the dehydrochloric acid-treated product of polyvinyl chloride, etc. are mentioned. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

A polarizer obtained by uniaxially stretching a polyvinyl alcohol-based film by dyeing it with iodine can be produced by, for example, dyeing by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching to 3 to 7 times the original length. If necessary, it may be immersed in an aqueous solution such as boric acid or potassium iodide. Also, if necessary, before dyeing, the polyvinyl alcohol-based film may be immersed in water and washed with water. By washing the polyvinyl alcohol-based film with water, it is possible to wash the surface of the polyvinyl alcohol-based film with an anti-contamination or blocking agent, and by swelling the polyvinyl alcohol-based film, there is an effect of preventing unevenness such as staining of dyeing. Stretching may be performed after dyeing with iodine, stretching while dyeing, or dyeing with iodine after stretching. It can be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, the curable adhesive of the present invention can remarkably exhibit its effect (it satisfies optical durability in a harsh environment under high temperature and high humidity) when a thin polarizer having a thickness of 10 µm or less is used as the polarizer. Polarizers having a thickness of 10 μm or less have a relatively large influence of moisture compared to polarizers having a thickness of more than 10 μm, have insufficient optical durability in an environment under high temperature and high humidity, and increase in transmittance or decrease in polarization is likely to occur. . That is, when the polarizer of 10 μm or less is laminated with an adhesive layer having a bulk absorption of 10% by weight or less of the present invention, the movement of water to the polarizer is suppressed in an environment under extreme high temperature and high humidity, thereby increasing the transmittance of the polarizing film, Deterioration in optical durability such as a decrease in polarization degree can be remarkably suppressed. It is preferable that the thickness of a polarizer is 1-7 micrometers speaking from a viewpoint of thinning. It is preferable that such a thin polarizer has little thickness unevenness, has excellent visibility, has few dimensional changes, and furthermore, the thickness as a polarizing film can be reduced in thickness.

As a thin polarizer, representatively, Japanese Laid-Open Patent Publication No. 51-069644 or Japanese Laid-Open Patent Publication No. 2000-338329, a pamphlet of WO2010/100917, a specification of PCT/JP2010/001460, or a specification of Japanese patent application 2010-269002 B. The thin polarizing film described in the specification of Japanese Patent Application No. 2010-263692 is mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) layer and a resin base material for stretching in a laminate state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it becomes possible to extend without problems such as fracture due to stretching by being supported by the resin substrate for stretching.

As the thin polarizing film, among the manufacturing methods including the step of stretching and dyeing in a laminated state, in that it can be stretched at a high magnification and thus the polarization performance can be improved, WO2010/100917 pamphlet, PCT/JP2010/001460 It is preferably obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in the specification of Japanese Patent Application 2010-269002 or specification of Japanese Patent Application 2010-269002 or specification of Japanese Patent Application 2010-269002. (B) It is preferable to obtain by a manufacturing method including a step of auxiliary air stretching before stretching in an aqueous boric acid solution described in the specification of Japanese Patent Application No. 2010-263692.

The thin high-performance polarizing film described in the above specification of PCT/JP2010/001460 is a thin high-function polarizing film having a thickness of 7 µm or less made of a PVA-based resin in which a dichroic substance is oriented, which is formed integrally with a resin substrate. This 42.0% or more and polarization degree have an optical property of 99.95% or more.

The thin high-performance polarizing film is formed by applying and drying a PVA-based resin on a resin substrate having a thickness of at least 20 μm to generate a PVA-based resin layer, and immersing the resulting PVA-based resin layer in a dye solution of a dichroic material. , By adsorbing the dichroic material to the PVA-based resin layer, and stretching the PVA-based resin layer to which the dichroic material is adsorbed, in a boric acid aqueous solution, integrally with the resin substrate so that the total draw ratio is 5 times or more of the original length, Can be manufactured.

In addition, as a method for producing a laminate film comprising a thin high-performance polarizing film in which a dichroic substance is oriented, a resin substrate having a thickness of at least 20 μm and an aqueous solution containing a PVA-based resin on one side of the resin substrate are applied and dried. The process of producing a laminate film comprising a PVA-based resin layer formed by doing so, and the laminate film comprising a resin substrate and a PVA-based resin layer formed on one side of the resin substrate are immersed in a dye solution containing a dichroic substance. By doing so, the process of adsorbing a dichroic substance to the PVA-based resin layer contained in the laminate film, and the laminate film including the PVA-based resin layer adsorbed with the dichroic substance, in a boric acid aqueous solution, the total draw ratio is A PVA-based resin layer in which a dichroic substance is oriented on one side of the resin substrate by stretching the process to be 5 times or more of the original length, and the PVA-based resin layer adsorbing the dichroic substance is stretched integrally with the resin substrate. The thin high-performance polarizing film can be produced by including the step of producing a laminate film comprising a thin high-functional polarizing film having optical properties having a thickness of 7 μm or less, a single transmittance of 42.0% or more and a polarization degree of 99.95% or more. I can.

The thin polarizing film of the above Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263692 is a polarizing film of a continuous web made of PVA-based resin in which a dichroic substance is oriented, and is based on an amorphous ester-based thermoplastic resin. The layered product including the film-produced PVA-based resin layer was stretched in a two-stage stretching step consisting of air-assisted stretching and boric acid in-water stretching, to obtain a thickness of 10 μm or less. In such a thin polarizing film, when the single transmittance is T and the polarization degree is P, P> -(10 ^{0.929T-42.4-1} ) × 100 (however, T <42.3), and P ≥ 99.9 (however, T ≥ 42.3) It is preferable to have optical properties that satisfy the conditions of.

Specifically, the thin polarizing film is a step of producing a stretched intermediate product comprising an oriented PVA-based resin layer by aerial high-temperature stretching of a PVA-based resin layer formed on an amorphous ester-based thermoplastic resin substrate of a continuous web. And, a step of producing a colored intermediate product comprising a PVA-based resin layer in which a dichroic substance (iodine or a mixture of iodine and an organic dye is preferable) is oriented by adsorption of the dichroic substance to the stretched intermediate product, and coloring It can be produced by a method for producing a thin polarizing film including a step of producing a polarizing film having a thickness of 10 μm or less comprising a PVA-based resin layer in which a dichroic substance is oriented by stretching the intermediate product in water with boric acid.

In this production method, it is preferable that the total draw ratio of the PVA-based resin layer film-formed on the amorphous ester-based thermoplastic resin substrate by aerial high-temperature stretching and boric acid-in-water stretching is 5 times or more. The liquid temperature of the aqueous boric acid solution for stretching boric acid in water may be 60°C or higher. Before stretching the colored intermediate product in an aqueous boric acid solution, it is preferable to perform an insolubilization treatment on the colored intermediate product, and in that case, performed by immersing the colored intermediate product in an aqueous boric acid solution whose liquid temperature does not exceed 40°C. It is desirable. The amorphous ester-based thermoplastic resin substrate may be amorphous polyethylene terephthalate containing copolymerized polyethylene terephthalate copolymerized with isophthalic acid, copolymerized polyethylene terephthalate copolymerized with cyclohexanedimethanol or other copolymerized polyethylene terephthalate, It is preferably made of a transparent resin, and its thickness can be 7 times or more of the thickness of the PVA-based resin layer to be produced. Moreover, the draw ratio of the aerial high-temperature stretching is preferably 3.5 times or less, and the stretching temperature of the aerial high-temperature stretching is preferably not less than the glass transition temperature of the PVA-based resin, and specifically in the range of 95°C to 150°C. In the case of performing aerial high-temperature stretching by uniaxial stretching at the free end, it is preferable that the total draw ratio of the PVA-based resin layer film-formed on the amorphous ester-based thermoplastic resin substrate is 5 times or more and 7.5 times or less. In addition, when performing aerial high-temperature stretching by fixed stage uniaxial stretching, it is preferable that the total draw ratio of the PVA-based resin layer formed into a film on the amorphous ester-based thermoplastic resin substrate is 5 times or more and 8.5 times or less.

More specifically, a thin polarizing film can be manufactured by the following method.

A base material for a continuous web of isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) obtained by copolymerizing 6 mol% of isophthalic acid was prepared. The glass transition temperature of amorphous PET is 75°C. A laminate made of a continuous web of amorphous PET substrate and a polyvinyl alcohol (PVA) layer is produced as follows. In addition, the glass transition temperature of PVA is 80°C.

A PVA aqueous solution having a concentration of 4 to 5% in which an amorphous PET substrate having a thickness of 200 µm and a PVA powder having a polymerization degree of 1000 or more and a saponification degree of 99% or more is dissolved in water is prepared. Next, a PVA aqueous solution was applied to an amorphous PET substrate having a thickness of 200 μm, and dried at a temperature of 50 to 60° C., to obtain a laminate having a PVA layer having a thickness of 7 μm on the amorphous PET substrate.

A laminate comprising a 7 µm-thick PVA layer is subjected to the following steps including a two-stage stretching step of air-assisted stretching and boric acid underwater stretching, to produce a thin, high-performance polarizing film having a thickness of 3 µm. By the air-assisted stretching step of the first stage, a laminate comprising a PVA layer having a thickness of 7 μm is integrally stretched with an amorphous PET substrate, and a stretched laminate comprising a PVA layer having a thickness of 5 μm is produced. Specifically, in this stretched laminate, a laminate including a 7 µm-thick PVA layer was hung on a stretching device disposed in an oven set in an environment of a stretching temperature of 130°C, and the stretch ratio was increased to 1.8 times with one free end. It is stretched. By this stretching treatment, the PVA layer contained in the stretched laminate is changed into a 5 µm-thick PVA layer in which PVA molecules are oriented.

Next, a colored laminate in which iodine is adsorbed onto a 5 μm-thick PVA layer in which PVA molecules are oriented is produced by a dyeing process. Specifically, in this colored laminate, a single transmittance of the PVA layer constituting the high-functional polarizing film finally produced is 40 to 44% in a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30°C. Iodine was adsorbed to the PVA layer contained in the stretched laminate by immersing for an arbitrary time as possible. In this step, the dyeing solution uses water as a solvent, the iodine concentration is in the range of 0.12 to 0.30% by weight, and the potassium iodide concentration is in the range of 0.7 to 2.1% by weight. The ratio of concentrations of iodine and potassium iodide is 1 to 7. In addition, potassium iodide is required to dissolve iodine in water. More specifically, by immersing the stretched laminate for 60 seconds in a dyeing solution having an iodine concentration of 0.30% by weight and potassium iodide concentration of 2.1% by weight, a colored layered product in which iodine is adsorbed on a 5 μm-thick PVA layer in which PVA molecules are oriented is prepared. Generate.

In addition, the colored laminate is further stretched integrally with the amorphous PET substrate by the second step of boric acid underwater stretching step, thereby producing an optical film laminate comprising a PVA layer constituting a high-functional polarizing film having a thickness of 3 μm. Specifically, in this optical film layered product, the colored layered product is hung on a stretching device disposed in a processing device set to an aqueous boric acid solution in a liquid temperature range of 60 to 85°C containing boric acid and potassium iodide, so that the draw ratio is 3.3 times. It is stretched with one free end. More specifically, the liquid temperature of the aqueous boric acid solution is 65°C. In addition, the boric acid content is 4 parts by weight based on 100 parts by weight of water, and the potassium iodide content is 5 parts by weight based on 100 parts by weight of water. In this step, the colored layered product in which the amount of iodine adsorption was adjusted is first immersed in an aqueous boric acid solution for 5 to 10 seconds. Thereafter, the colored laminate is passed between a plurality of sets of rolls having different circumferential velocities as a stretching device arranged in the processing device as it is, and stretching is performed with one free end axis so that the draw ratio is 3.3 times over 30 to 90 seconds. By this stretching treatment, the PVA layer contained in the colored laminate is changed into a 3 µm-thick PVA layer in which the adsorbed iodine is oriented in one direction as a polyiodine ion complex. This PVA layer constitutes a highly functional polarizing film of an optical film laminate.

Although it is not an essential process for the production of the optical film laminate, the optical film laminate is taken out from the aqueous boric acid solution by the cleaning process, and boric acid adhering to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate is iodized. It is preferable to wash with an aqueous potassium solution. Then, the washed optical film layered product is dried by a drying step with a warm air at 60°C. In addition, the washing step is a step for eliminating appearance defects such as precipitation of boric acid.

Although it is not an essential step for the production of the same optical film laminate, the adhesive is applied to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate by the bonding and/or transfer process, while the thickness of 80 μm After bonding the triacetylcellulose film of, the amorphous PET substrate may be peeled off, and the PVA layer having a thickness of 3 µm may be transferred to a triacetyl cellulose film having a thickness of 80 µm.

[Other processes]

The manufacturing method of the thin polarizing film described above may include other steps in addition to the above steps. As another process, an insolubilization process, a crosslinking process, a drying (control of a moisture content) process, etc. are mentioned, for example. Other steps can be carried out at any appropriate timing.

The insolubilization step is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by performing the insolubilization treatment. The concentration of the aqueous boric acid solution is preferably 1 part by weight to 4 parts by weight based on 100 parts by weight of water. The liquid temperature of the insolubilization bath (boric acid aqueous solution) is preferably from 20°C to 50°C. Preferably, the insolubilization process is performed after the production of the laminated body and before the dyeing process or the underwater stretching process.

The crosslinking step is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by performing crosslinking treatment. The concentration of the aqueous boric acid solution is preferably 1 part by weight to 4 parts by weight based on 100 parts by weight of water. Moreover, when performing a crosslinking process after the said dyeing process, it is preferable to mix|blend an iodide further. By blending iodide, elution of iodine adsorbed to the PVA-based resin layer can be suppressed. The blending amount of iodide is preferably 1 to 5 parts by weight based on 100 parts by weight of water. Specific examples of iodide are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably from 20°C to 50°C. Preferably, the crosslinking step is performed before the second boric acid underwater stretching step. In a preferred embodiment, a dyeing step, a crosslinking step, and a second boric acid-in-water stretching step are performed in this order.

<Transparent protective film>

As a material for forming the transparent protective film formed on one or both sides of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropic properties, and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose or triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, polystyrene or acrylonitrile-styrene copolymer Styrene-based polymers, such as (AS resin), polycarbonate-based polymers, etc. are mentioned. In addition, polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, polyolefin-based polymer such as ethylene-propylene copolymer, vinyl chloride-based polymer, amide-based polymer such as nylon or aromatic polyamide, imide-based polymer, alcohol Pone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, Epoxy polymers, blends of the polymers, etc. are also exemplified as polymers forming the transparent protective film. One or more types of arbitrary suitable additives may be contained in the transparent protective film. As an additive, an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, etc. are mentioned, for example. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably 70 to 97% by weight. . When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, there is a concern that the high transparency inherent in the thermoplastic resin cannot be sufficiently expressed.

Moreover, as a transparent protective film, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007), for example, (A) a thermoplastic resin having a substituted and/or unsubstituted imide group in the side chain, and ( B) A resin composition containing a thermoplastic resin having a substituted and/or unsubstituted phenyl and nitrile group in the side chain is mentioned. As a specific example, a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer is mentioned. As the film, a film made of a mixed extrusion product of a resin composition or the like can be used. Since these films have a small retardation and a small photoelastic coefficient, problems such as nonuniformity due to deformation of the polarizing film can be solved, and since the moisture permeability is small, the humidification durability is excellent.

In the polarizing film, it is preferable that the moisture permeability of the transparent protective film is 150 g/m 2 /24 h or less. According to such a configuration, moisture in the air is difficult to enter into the polarizing film, and a change in the moisture content of the polarizing film itself can be suppressed. As a result, curling and dimensional change of the polarizing film caused by the storage environment can be suppressed.

As the material for forming the transparent protective film formed on one or both sides of the polarizer, it is preferable to have excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc., and particularly those having a moisture permeability of 150 g/m 2 /24 h or less It is more preferable, and the thing of 140 g/m 2 /24 h or less is especially preferable, and the thing of 120 g/m 2 /24 h or less is still more preferable. The moisture permeability is determined by the method described in the examples.

As a material for forming the transparent protective film satisfying the low moisture permeability, for example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; arylate resins; amide resins such as nylon and aromatic polyamides. Polyolefin-based polymers such as polyethylene, polypropylene, and ethylene-propylene copolymer, cyclic olefin-based resins having a cyclo-based or norbornene structure, (meth)acrylic-based resins, or mixtures thereof can be used. Among the above resins, polycarbonate resins, cyclic polyolefin resins, and (meth)acrylic resins are preferable, and cyclic polyolefin resins and (meth)acrylic resins are particularly preferable.

The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 100 µm in terms of workability such as strength and handling properties, and thin layer properties. In particular, 1 to 80 µm is preferable, and 3 to 60 µm is more preferable.

In addition, when forming a transparent protective film on both sides of a polarizer, a transparent protective film made of the same polymer material may be used on the front and back, or a transparent protective film made of a different polymer material or the like may be used.

Functional layers such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer may be formed on the surface of the transparent protective film on which the polarizer is not adhered. In addition, functional layers such as the hard coat layer, anti-reflection layer, anti-sticking layer, diffusion layer or anti-glare layer may be formed separately from the transparent protective film, in addition to being formed on the transparent protective film itself. May be.

<optical film>

In practical use, the polarizing film of the present invention can be used as an optical film laminated with another optical layer. The optical layer is not particularly limited, but for example, a reflection plate, a transflective plate, a retardation plate (including a wavelength plate such as 1/2 or 1/4), and a liquid crystal display device such as a visual compensation film. One or two or more optical layers that may be used may be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by laminating a reflective or semi-transmissive reflecting plate in addition to the polarizing film of the present invention, an elliptically polarizing film or a circular polarizing film obtained by laminating a retardation plate in addition to a polarizing film, or a polarizing film Further, a wide viewing angle polarizing film formed by laminating a visual compensation film, or a polarizing film formed by laminating a luminance enhancing film further on a polarizing film is preferable.

The optical film in which the optical layer is laminated on a polarizing film can be formed by sequentially laminating separately in the manufacturing process of a liquid crystal display device, etc., but the pre-laminated optical film is used for stability of quality or assembly work. This is excellent, and there is an advantage that the manufacturing process of a liquid crystal display device etc. can be improved. For lamination, an appropriate adhesive means such as an adhesive layer can be used. In the adhesion of the above-described polarizing film and other optical films, their optical axes can be set to an appropriate arrangement angle depending on the target retardation characteristic or the like.

An adhesive layer for bonding to other members such as a liquid crystal cell may be formed on the above-described polarizing film or the optical film in which at least one polarizing film is laminated. The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer is not particularly limited, but for example, an acrylic polymer, a silicone polymer, polyester, polyurethane, polyamide, polyether, a fluorine-based or rubber-based polymer can be appropriately selected and used as a base polymer. have. In particular, those having excellent optical transparency, suitable wettability, cohesiveness and adhesive properties, such as excellent weather resistance and heat resistance, can be preferably used like acrylic pressure-sensitive adhesives.

The adhesive layer may be formed on one side or both sides of a polarizing film or an optical film as an overlapping layer of different compositions or types. Moreover, in the case of forming on both sides, it is also possible to use an adhesive layer such as a different composition, type, or thickness in the front and back of a polarizing film or an optical film. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, etc., and is generally 1 to 500 µm, preferably 1 to 200 µm, and particularly preferably 1 to 100 µm.

With respect to the exposed surface of the adhesive layer, a separator is temporarily attached and covered for the purpose of preventing contamination or the like until it is provided for practical use. Thereby, it is possible to prevent contact with the adhesive layer in the usual handling state. As the separator, except for the above-described thickness conditions, for example, suitable thin-walled materials such as plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foam sheet, metal foil, and laminates thereof may be used as necessary, such as silicone-based or long-chain alkyl. It is possible to use suitable ones conforming to the prior art, such as those coated with an appropriate release agent such as fluorine-based or molybdenum sulfide.

<Image display device>

The polarizing film or optical film of the present invention can be preferably used for formation of various devices such as a liquid crystal display device. The formation of a liquid crystal display device can be carried out according to the prior art. That is, in general, a liquid crystal display device is formed by properly assembling a liquid crystal cell, a polarizing film or an optical film, and constituent parts such as a lighting system according to need, and inserting a driving circuit. However, in the present invention, There is no limitation in particular except for using a polarizing film or an optical film, and it may follow conventionally. Also for the liquid crystal cell, for example, any type such as TN type, STN type, or π type can be used.

An appropriate liquid crystal display device, such as a liquid crystal display device in which a polarizing film or an optical film is disposed on one or both sides of a liquid crystal cell, or a backlight or a reflector in an illumination system, can be formed. In that case, the polarizing film or optical film according to the present invention can be installed on one side or both sides of a liquid crystal cell. When forming a polarizing film or an optical film on both sides, they may be the same thing or different things may be sufficient. In addition, in the formation of a liquid crystal display device, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. It can be placed above.

Example

Examples of the present invention are described below, but embodiments of the present invention are not limited thereto.

<Production of polarizer>

A 75 µm-thick polyvinyl alcohol film having an average degree of polymerization of 2400 and a degree of saponification of 99.9 mol% was immersed in hot water at 30° C. for 60 seconds to swell. Next, it was immersed in an aqueous solution having a concentration of 0.3% of iodine/potassium iodide (weight ratio = 0.5/8), and the film was dyed while stretching to 3.5 times. Then, it extended|stretched so that the draw ratio of the total might become 6 times in 65 degreeC boric acid ester aqueous solution. After extending|stretching, it dried for 3 minutes in a 40 degreeC oven, and obtained the PVA-type polarizer X (thickness 23 micrometers).

<Transparent protective film>

Transparent protective film 1: A triacetyl cellulose film (moisture permeability 530 g/m 2 /24 h) having a thickness of 60 μm was used without saponification and corona treatment (in Table 1, it is expressed as TAC).

Transparent protective film 2: The (meth)acrylic resin (meth)acrylic resin having a lactone ring structure having a thickness of 40 µm (moisture permeability 96 g/m 2 /24 h) was subjected to corona treatment and used (in Table 1, it is indicated as acrylic).

Transparent protective film 3: Corona treatment was applied to and used for a 55 µm-thick cyclic polyolefin film (manufactured by Nippon Xeon Corporation: ZEONOR, moisture permeability 11 g/m 2 /24 h) (in Table 1, it is referred to as COP).

<Moisture permeability of transparent protective film>

The measurement of moisture permeability was measured according to the moisture permeability test (cup method) of JIS Z0208. A sample cut into a diameter of 60 mm was set in a moisture-permeable cup containing about 15 g of calcium chloride, and a temperature of 40°C and a humidity of 90% R.H. The moisture permeability (g/m 2 /24 h) was calculated|required by measuring the weight increase of calcium chloride before and after putting it into the thermostat of and leaving for 24 hours.

<Active energy ray>

As an active energy ray, visible light (gallium-enclosed metal halide lamp) irradiation device: Fusion UV Systems, Inc. Light HAMMER10 valve: V valve peak illuminance: 1600 mW/c㎡, accumulated irradiation dose 1000/mJ/c㎡ (wavelength 380 -440 nm) was used. In addition, the illuminance of visible light was measured using the Sola-Check system manufactured by Solatell.

Examples 1 to 4 and Comparative Examples 1 to 5

(Preparation of active energy ray-curable adhesive)

According to the formulation table shown in Table 1, each component was mixed and stirred at 50° C. for 1 hour to obtain an active energy ray-curable adhesive according to Example 1 and Comparative Example 1. In addition, the viscosity of the active energy ray-curable adhesive according to Example 1 was 95 cp (25°C), and the viscosity of the active energy ray-curable adhesive according to Comparative Example 1 was 45 cp (25°C).

(Production of polarizing film)

On the transparent protective film, an active energy ray-curable adhesive according to the above Examples or Comparative Examples was applied with an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (Cell shape: honeycomb, gravure roll player: 1000 pieces/inch, rotation speed 140%) In line), it applied so as to have a thickness of 0.7 µm, and bonded to both surfaces of the polarizer X with a roll machine. Thereafter, from the bonded transparent protective film side (both sides), heated to 50°C using an IR heater, and irradiated with the visible light on both sides to cure the active energy ray-curable adhesive according to the Example or Comparative Example. And hot air drying at 70° C. for 3 minutes to obtain a polarizing film having a transparent protective film on both sides of the polarizer. The line speed of bonding was performed at 25 m/min.

Preparation of a polarizing film was performed about each of the three types of the said transparent protective films 1-3.

The following evaluation was performed about the polarizing film obtained by the said Example and a comparative example. Table 1 shows the evaluation results. In addition, in the evaluation of humidification durability and adhesion water resistance, each separately produced the same polarizing film.

<Bulk absorption rate>

Using the curable adhesive for a polarizing film used in each example, it was placed between two glass furnaces with a 100 µm spacer, and cured under the same active energy conditions as in the examples to obtain an adhesive layer (cured product) having a thickness of 100 µm. Prepared. This was taken as a sample. The weight of the sample was taken as M1 g. Sample M1g was immersed in 23 degreeC pure water for 24 hours. Then, within 1 minute after taking out from pure water and wiping with a dry cloth, the weight (M2g) of a sample was measured again. From their results,

Equation: ｛(M2-M1)/M1｝×100 (%),

By, the bulk water absorption was calculated.

<hardening shrinkage rate>

It measured with the curing shrinkage sensor "resin curing shrinkage stress measuring apparatus EU201C" by a Sentech company. Specifically, the cure shrinkage rate is calculated by the method described in Japanese Unexamined Patent Application Publication No. 2013-104869. In addition, the cured shrinkage ratio of the cured product formed from the active energy ray-curable adhesive according to Example 1 was 8.9%, and the cured shrinkage ratio of the cured product formed from the active energy ray-curable adhesive according to Comparative Example 1 was 11.9%.

<Adhesion>

The polarizing film obtained in each example was cut to a size of 200 mm in parallel with the stretching direction of the polarizer and 20 mm in the direct direction, and cut with a cutter knife between the transparent protective film and the polarizer, and the polarizing film was bonded to the glass plate. With tensilon, the transparent protective film and the polarizer were peeled off at a peeling speed of 500 mm/min in the 90-degree direction, and the peeling strength was measured. Moreover, the infrared absorption spectrum of the peeling surface after peeling was measured by the ATR method, and the peeling interface was evaluated based on the following criteria.

A: Cohesive failure of the transparent protective film

B: Interface peeling between transparent protective film/adhesive layer

C: Interface peeling between adhesive layer/polarizer

D: Cohesive destruction of polarizer

In the above criteria, A and D mean that the adhesion is very excellent because the adhesion is more than the cohesive strength of the film. On the other hand, B and C mean that the adhesive force of the transparent protective film/adhesive layer (adhesive layer/polarizer) interface is insufficient (inferior adhesive force). In consideration of these, the adhesive strength in the case of A or D is ○, A·B (“cohesive failure of the transparent protective film” and “interfacial peeling between the transparent protective film/adhesive layer” occur simultaneously) or A·C (“transparent protection” Cohesive failure of the film" and "interfacial peeling between the adhesive layer/polarizer" occur at the same time), the adhesive force in the case of Δ, and the adhesive force in the case of B or C is ×.

<Humidification durability: Measurement of single transmittance and polarization degree change>

As a transparent protective film, a polarizing film in which transparent protective films 2 and 3 were laminated one by one on both surfaces of a polarizer was prepared as a sample by the same method as in Examples and Comparative Examples. The said polarizing film (sample) was put into an 85 degreeC/85% RH thermohygrostat for 500 hours. The single transmittance and polarization degree of the polarizing film before and after the injection were measured using a spectral transmittance meter with an integrating sphere (Dot-3c of Murakami Color Research Institute),

Change amount of single transmittance (ΔT: %) = (Single transmittance after injection (%))-(Single transmittance before injection (%)),

The amount of change in polarization degree (ΔP: %) = (polarization degree after injection (%))-(polarization degree before injection (%)), was calculated|required.

In addition, the polarization degree P is the transmittance (parallel transmittance: Tp) when two identical polarizing films are superimposed so that their transmission axes are parallel to each other, and the transmittance (orthogonal transmittance) when they are superimposed so that both transmission axes are orthogonal. : It is calculated|required by applying Tc) to the following formula. Polarization P (%) =｛(Tp-Tc)/(Tp + Tc)｝ ^1/2 × 100

Each transmittance is expressed as a Y value obtained by correcting luminous sensitivity by a 2nd degree field of view (C light source) of JIS Z8701 with 100% of the complete polarization obtained through a Glen Taylor prism polarizer.

<Adhesion water resistance (hot water immersion test)>

As a transparent protective film, a polarizing film in which transparent protective films 1 and 3 were laminated one by one on both surfaces of a polarizer each was produced as a sample by the same method as in Examples and Comparative Examples. The polarizing film (sample) was cut into a rectangle of 50 mm in the stretching direction of the polarizer and 25 mm in the vertical direction. After immersing such a polarizing film in hot water at 60° C. for 6 hours, the peeled length was visually measured with a magnifying glass. The measurement was taken as the maximum value of the vertical distance from the cross section of the part where peeling occurred (mm).

<Adhesion water resistance (water resistance peeling power)>

As a transparent protective film, a polarizing film in which transparent protective films 1 and 3 were laminated one by one on both surfaces of a polarizer each was produced as a sample by the same method as in Examples and Comparative Examples. The polarizing film (sample) was cut to a size of 200 mm in parallel with the stretching direction of the polarizer and 20 mm in the direct direction. After immersing the said polarizing film in pure water at 23 degreeC for 24 hours, after taking out from pure water and wiping off with a dry cloth, it cut|disconnected with a cutter knife between a transparent protective film and a polarizer, and the polarizing film was bonded to a glass plate. After taking out from pure water, evaluation was performed within 1 minute. After that, evaluation similar to the said <adhesive force> was performed.

<Calculation of logPow>

Using the logPow value of each compound obtained by Chem DrawUltra (manufactured by Cambridge Soft), calculation was performed by the following formula. In addition, the polymerization initiator and photoacid generator were excluded from the calculation.

LogPow of curable adhesive = Σ (logPowi × Wi)

logPowi: The logPow value of each component of the curable adhesive

Wi: (number of moles of i component)/(total number of moles of each component of curable adhesive)

In Table 1, the radical polymerizable compound,

HEAA: hydroxyethylacrylamide, logPow = -0.56, homopolymer Tg = 123°C, manufactured by Kyojin Corporation;

ACMO: Acryloylmorpholine, logPow = -0.20, homopolymer Tg = 150°C, manufactured by Kyojin Corporation;

FA-THFM: Tetrahydrofurfuryl (meth)acrylate, logPow = 1.13, homopolymer Tg = 45°C, manufactured by Hitachi Hwaseong;

Light acrylate DCP-A: tricyclodecanedimethanol diacrylate, logPow = 3.05, homopolymer Tg = 134°C, manufactured by Kyoeisha Chemical Co., Ltd.;

Light acrylate 1,9 ND-A: 1,9-nanonediol diacrylate, logPow = 3.68, homopolymer Tg = 68°C, manufactured by Kyoeisha Chemical Co., Ltd.;

Aaronix M-220: Tripropylene glycol diacrylate, logPow = 1.68, homopolymer Tg 69°C, manufactured by Toa Synthetic Company;

Aaronix M-306: pentaerythritol tri/tetraacrylate, logPow = 1.04, homopolymer Tg = 250°C or higher, manufactured by Toa Synthetic Co.;

Acrylic oligomer: ARUFON UP-1190, logPow = 1.95 manufactured by Toa Synthetic,

Compound containing an alkoxy group: Nikarakku MX-750LM, logPow = 0.8 manufactured by Nippon Carbite Industries,

Compound containing an epoxy group: JER828, logPow = 4.76 manufactured by Japan Epoxy Resin Co., Ltd.

Isocyanate compound: Karenz AOI, logPow = 1.6 represents Showa Electric Co., Ltd. product).

The photopolymerization initiator,

IRGACURE907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one), logPow = 2.09, manufactured by BASF

KAYACURE DETX-S (diethyl thioxanthone), logPow = 5.12, Nippon Explosives Corporation make, are shown.

The photoacid generator represents CPI-100P (a propylene carbonate solution containing 50% of an active ingredient containing triarylsulfonium hexafluorophosphate as a main component), manufactured by San Apro.

Claims (12)

As a curable adhesive for polarizing films containing a curable component,
When the curable adhesive for polarizing films is immersed in 23° C. pure water for 24 hours, the cured product obtained by curing the curable adhesive is the following formula:
Bulk absorption rate (%) =｛(M2-M1)/M1｝×100,
However, in the above formula, M1 represents the weight of the cured product before immersion, and M2 represents the weight of the cured product after immersion.
The curable component is an active energy ray-curable component, and further contains an acrylic oligomer (A) obtained by polymerizing a (meth)acryl monomer, a photoacid generator (B), and a compound (C1) containing an alkoxy group. Curable adhesive for polarizing film to be used. The method of claim 1,
The curable adhesive for polarizing films, wherein the octanol/water partition coefficient (logPow value) of the curable adhesive for polarizing films is 1 or more and 8 or less. The method of claim 1,
The curable adhesive for polarizing films, wherein the active energy ray-curable component contains a radical polymerizable compound. The method of claim 3,
The curable adhesive for polarizing films, characterized in that the radical polymerizable compound contains a (meth)acrylamide derivative. The method of claim 3,
The curable adhesive for a polarizing film, wherein the radical polymerizable compound contains a polyfunctional compound having at least two functional groups having radical polymerizable properties. The method of claim 1,
Further, a curable adhesive for polarizing films comprising a photoinitiator. The method of claim 1,
The curable adhesive for polarizing films, wherein the compound (C1) containing an alkoxy group is a melamine compound containing an alkoxy group. The method of claim 1,
Further, the curable adhesive for polarizing films, comprising an isocyanate compound (D). A polarizing film in which a transparent protective film is formed on at least one side of a polarizer through an adhesive layer,
The polarizing film, wherein the adhesive layer is formed by a cured product layer of the curable adhesive for polarizing films according to any one of claims 1 to 8. The method of claim 9,
Polarizing film, characterized in that the thickness of the cured adhesive layer is 0.1 to 3 ㎛. An optical film characterized in that at least one polarizing film according to claim 9 is laminated. An image display device, wherein the polarizing film according to claim 9 or an optical film in which at least one polarizing film is laminated is used.