JP5652951B2 - High durability polarizing plate provided with a layer obtained from a polymerizable resin composition - Google Patents

Description

The present invention relates to a polarizing plate with improved durability.

In general, a polarizing element film is produced by adsorbing and orienting a dichroic dye, iodine or a dichroic dye, onto a polyvinyl alcohol resin film. A protective film made of triacetyl cellulose or the like is bonded to at least one surface of this polarizing element film via an adhesive layer to form a polarizing plate, which is used for a liquid crystal display device or the like. A polarizing plate using iodine as a dichroic dye is called an iodine polarizing plate, while a polarizing plate using a dichroic dye as a dichroic dye is called a dye polarizing plate. Among these, iodine-based polarizing plates are widely used for general liquid crystal monitors, liquid crystal televisions, mobile phones, PDAs and the like because they exhibit higher transmittance and higher degree of polarization, that is, higher contrast than dye-based polarizing plates. It has been. However, although iodine-based polarizing plates are superior to dye-based polarizing plates in terms of optical properties, they are greatly inferior to dye-based polarizing plates in terms of optical durability. For example, iodine-based polarizing plates are left under high temperature and high humidity. As a result, problems such as large decolorization and a decrease in the degree of polarization occurred. Moreover, even if it is a dye-type polarizing plate, the optical characteristic does not change at all in a wet heat test, and the further high durability is desired.

JP-A-8-5836 JP 2001-272534 A JP2004-12578 JP 2001-166139 A JP2003-185842 JP-A-2004-77579

Published by Technical Center for UV Curing Systems, written by Kiyomi Kato, P259-303

There is a demand for a polarizing plate having high transmittance and degree of polarization, high contrast, and excellent heat and humidity resistance. As an invention for this request, as described in Patent Document 1 and Patent Document 2, an improvement method using a protective film of an iodine-based polarizing plate, or a protective film of triacetyl cellulose as in Patent Document 3 and Patent Document 4 It is described that dry heat durability and wet heat durability can be improved by a method of modifying an adhesive for adhering. As described above, there is a technique in which the durability of the polarizing plate is improved by the protective film or the adhesive. However, it is not yet sufficient, and an improvement in wet heat durability of an inexpensive and simple polarizing plate is desired.

Furthermore, as a prescription for improving the durability of a polarizing plate, a polarizing plate having a protective layer formed of an energy beam polymerizable compound on one surface of a polarizer as in Patent Document 5 and Patent Document 6 is known. However, just having a protective layer formed of an energy beam polymerizable compound on one side of the polarizer as in the prescription of Patent Document 5 or Patent Document 6 is insufficient in wet heat durability, and the film thickness of the protective layer In some cases, the uncured monomer of the polymerizable compound increases, and conversely, the wet heat durability and the dry heat durability are lowered, and the adhesion is insufficient. In addition, there is a polarizing plate having a cured resin layer such as a hard coat layer, which is a known technique, but simply providing a resin layer such as a hard coat layer does not necessarily improve wet heat durability to a high degree, It was a polarizing plate with severe deterioration such as discoloration in the durability test.

As a result of intensive studies to solve the above problems, a polymerizable resin composition excluding a solvent for a polarizing plate using a polarizing element film obtained from a hydrophilic polymer obtained by adsorbing and stretching a dichroic dye and a crosslinking agent In 100 parts by weight, the moisture permeability of the resin film layer in a (meth) acrylate compound having two or more (meth) acryloyl groups and a film thickness of 5 μm is 1500 g / m ² or less in 24 hours. 30 to 98 parts by weight of at least one (meth) acrylate compound (A) and at least one (meth) acrylate compound (B) having a solubility in water at 25 ° C. of 1% by weight or less. It has a layer obtained by curing a polymerizable resin composition containing 1 to 70 parts by weight and a polymerization initiator (C) 0.1 to 10 parts by weight, and the thickness of the layer is 0.5 to 10 μm. A layer at least A polarizing plate characterized in that it is provided with more than one layer has a new feature that durability, mainly wet heat durability, is greatly improved, and a polarizing plate in which color change does not occur even in dry heat durability can be obtained. I found it.

That is, the present invention
“(1) In 100 parts by weight of a polymerizable resin composition excluding a solvent, (meta) on a polarizing plate using a polarizing element film obtained from a hydrophilic polymer stretched by adsorbing a dichroic dye and a crosslinking agent. ) A (meth) acrylate compound having two or more acryloyl groups, and when the cured resin film layer has a thickness of 5 μm, the moisture permeability of the resin film layer is at least 1500 g / m ^{2 in} 24 hours. 30 to 98 parts by weight of the above (meth) acrylate compound (A), and 1 to 70 parts by weight of at least one (meth) acrylate compound (B) having a solubility in water of 25 ° C. of 1% by weight or less. And a layer obtained by curing a polymerizable resin composition containing 0.1 to 10 parts by weight of a polymerization initiator (C), the thickness of the layer being 0.5 to 10 μm, A layer obtained by curing the resin composition In the laminated structure of the polarizing plate, at least one layer is provided between the protective layer and the polarizing element film in the protective layer / adhesive layer / polarizing element film / adhesive layer / protective layer structure. Polarizer.
(2) Polarized light in which the layer obtained by curing the polymerizable resin composition is composed of a protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer The polarizing plate according to (1), wherein the plate is provided with at least one layer between the protective layer (L) and the polarizing element film.
(3) Polarized light in which the layer obtained by curing the polymerizable resin composition is composed of a protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer In the plate, at least one or more layers are provided between the protective layer (L) and the adhesive layer (L), The polarizing plate according to any one of (1) and (2).
(4) In the polarizing plate constituted by the protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer, the polymerizable resin composition was cured. At least one layer is provided between the protective layer (L) and the adhesive layer (L), between the protective layer (M) and the adhesive layer (M). The polarizing plate according to any one of (1) to (3), which is characterized. "
Concerning.

The polarizing plate of the present invention is a polarizing plate with little decolorization and little change in transmittance and lowering of the degree of polarization even in the case of an iodine-based polarizing plate at a temperature of 65 ° C. and a relative humidity of 93% in a humid heat environment. A polarizing plate having high transmittance, high contrast, and high durability in a polarizing plate for display can be obtained. The polarizing plate having a layer obtained by curing the polymerizable resin composition of the present invention not only greatly improves durability, but also has good adhesion, and the resin layer is discolored by heat or humidity. It has the feature of not happening.

Hereinafter, the present invention will be described in detail.
The present invention relates to a polarizing plate using a polarizing element film obtained from a stretched hydrophilic polymer adsorbing a dichroic dye and a crosslinking agent, in 100 parts by weight of a polymerizable resin composition excluding a solvent, ) A (meth) acrylate compound having two or more acryloyl groups, and when the cured resin film layer having a film thickness of 5 μm is formed, the moisture permeability of the resin film layer is 1500 g / m ² or less in 24 hours. 30 to 98 parts by weight of the (meth) acrylate compound (A) and 1 to 70 parts by weight of at least one (meth) acrylate compound (B) having a solubility in water at 25 ° C. of 1% by weight or less, It has a layer obtained by curing a polymerizable resin composition containing 0.1 to 10 parts by weight of a polymerization initiator (C), and at least one layer having a thickness of 0.5 to 10 μm. It is provided It relates polarizing plate according to claim.

The compound having a (meth) acryloyl group is a compound as shown in Non-Patent Document 1, for example. However, the present invention is not limited to Non-Patent Document 1, and a compound having a known (meth) acryloyl group can be used. A polymerizable resin composition is prepared using these compounds and a polymerization initiator. However, in the present invention, even in the case of a compound having a (meth) acryloyl group, in the compound (A) having two or more (meth) acryloyl groups, the resin has a thickness of 5 μm after curing. A film layer is formed, and the resin film layer is characterized in that the moisture permeability based on JIS-Z0208 is 1500 g / m ² or less in 24 hours. More preferably, the moisture permeability is 1100 g / m ² or less in 24 hours, more preferably 900 g / m ² or less in 24 hours, and more preferably 800 g / m ² or less in 24 hours. It is preferable.

The method for evaluating the moisture permeability is a compound having a (meth) acryloyl group on a semi-bleached kraft paper (obtained from Totsuya Echo Co., Ltd.) coated with polyvinyl alcohol having a solid content concentration of 5% by weight to a thickness of 1 μm. Apply. The compound having a (meth) acryloyl group is mixed with 10 parts by weight of a resin having a (meth) acryloyl group, 5 parts by weight of toluene, and 0.6 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184 manufactured by Ciba Specialty Chemicals). And it was set as the composition. The composition was applied to the semi-bleached kraft paper to which polyvinyl alcohol was anchor-coated so that the resin solid content after solvent evaporation would be 5 μm thick. The moisture permeability of the paper was measured based on JIS-Z0208.

この結果から、ジエチレングリコールジアクリレート、ならびにポリエチレングリコール４００ジアクリレートなどは透湿度が高い。 Table 1 shows the moisture permeability of the coating film made of the compound having a (meth) acryloyl group obtained by the above method.

Table 1 Moisture permeability when a compound having a (meth) acryloyl group is used as a coating film

From this result, diethylene glycol diacrylate and polyethylene glycol 400 diacrylate have high moisture permeability.

The wet heat durability is improved by using a compound having low moisture permeability when the coating film shown in Table 1 is used. However, in a compound that cures, sufficient hardness, adhesion, and durability of the polarizing plate cannot be further improved simply by forming a layer. In order to improve the durability, at least one (meth) acrylate compound (A) having two or more (meth) acryloyl groups having a moisture permeability of not more than 1500 g / m ^{2 in} 24 hours when the coating film is formed is used. ), And a polymerizable resin composition comprising at least one (meth) acrylate compound (B) having a solubility in water of 25 ° C. of 1% by weight or less and a polymerization initiator (C). It is good to be. The content thereof is 30 to 98 parts by weight of at least one (meth) acrylate compound (A) and 1 to 70 of (meth) acrylate compound (B) in 100 parts by weight of the polymerizable resin composition excluding the solvent. It is preferable to contain 0.1 to 10 parts by weight of a polymerization initiator (C).

One or more (meth) acrylate compounds (B) having a solubility in water at 25 ° C. of 1% by weight or less are more preferable as the solubility of the (meth) acrylate compound in water is lower. As a method for confirming the solubility of the (meth) acrylate compound in water at 25 ° C., the solubility when the (meth) acrylate compound in 100 g of distilled water at 25 ° C. is mixed may be confirmed. The (meth) acrylate compound having a solubility in water of 1% by weight or less corresponds to the (meth) acrylate compound (B) used in the present invention. When the solubility of the (meth) acrylate compound in water is high, that is, when the hydrophilicity is strong, the water absorption rate of the layer obtained by the polymerizable resin composition is high, leading to improvement in adhesion and optical durability. Absent. Moreover, according to this method, even if it is a (meth) acrylate compound with only one (meth) acryloyl group which cannot measure the moisture permeability of Table 1, solubility can be measured and it is useful as a parameter.

表２から分かるように、ブタンジオールモノアクリレート、N,N-ジメチルアミノエチルアクリレート、N,N-ジメチルアミノエチルメタクリレート、２−エトキシエチルアクリレート、２−ヒドロキシエチルアクリレート、２−ヒドロキシエチルメタクリレート、ヒドロキシプロピルアクリレート、２−メトキシエチルアクリレート、ビニルアセテート、N-ビニルカプロラクタム、N-ビニルピロリドン、ポリエチレングリコール４００ジアクリレート又はポリエチレングリコール２００ジアクリレートの２５℃の水に対する溶解度は１重量％以上である。これらのような（メタ）アクリレート化合物を用いてしまうと、硬度、密着性、偏光板の耐久性を向上するには至らない。 It can be confirmed from Table 2 below whether the compound does not correspond to the (meth) acrylate compound (B) whose solubility in water at 25 ° C. is 1% by weight or less.

Table 2 Solubility of compounds having a (meth) acryloyl group (g / 100 ml water)

As can be seen from Table 2, butanediol monoacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, 2-ethoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl The solubility of acrylate, 2-methoxyethyl acrylate, vinyl acetate, N-vinylcaprolactam, N-vinylpyrrolidone, polyethylene glycol 400 diacrylate or polyethylene glycol 200 diacrylate in water at 25 ° C. is 1% by weight or more. If such (meth) acrylate compounds are used, the hardness, adhesion, and durability of the polarizing plate cannot be improved.

Further, in the (meth) acrylate compound (B), in order to further improve the hardness, adhesion, and durability of the polarizing plate, the molecule has at least one hydroxyl group and one (meth) acryloyl group. The (meth) acrylate compound (a) having at least one or the (meth) acrylate compound (b) having at least one dicyclopentadiene group and having at least one (meth) acryloyl group is used. good. The (meth) acrylate compound (B) may have at least one (meth) acryloyl group. The durability of the compound having a hydroxyl group in the molecule is improved even if at least one kind is contained in 100 parts by weight of the polymerizable resin composition, but it is preferably 10 parts by weight or more, more preferably It is preferable to contain 20 parts by weight or more, more preferably 30 parts by weight or more.

As the (meth) acrylate compound (a) having at least one hydroxyl group and at least one (meth) acryloyl group in the molecule, EHC-modified butyl acrylate (Denacol DA-151 manufactured by Nagase Sangyo Co., Ltd.), Glycerol methacrylate (Blenmer GLM manufactured by Nippon Oil & Fats Co., Ltd.), 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride (Blenmer QA manufactured by Nippon Oil & Fats Co., Ltd.), EO-modified phosphoric acid acrylate (Light Ester PA manufactured by Kyoeisha Oil & Fats Co., Ltd.), EO-modified phthalic acid acrylate (Biscoat 2308 manufactured by Osaka Organic Chemicals Co., Ltd.), EO, PO-modified phthalic acid methacrylate (Light Ester HO manufactured by Kyoeisha Yushi Co., Ltd.), Acrylic isocyanurate (Aronix M-215 manufactured by Toagosei Co., Ltd.), EO-modified Hisphenol A diacrylate (Nipponization) Kayrad made by Yakuhin
R-115), dipentaerythritol monohydroxypentaacrylate (SR-399 manufactured by Sartomer), glycerol dimethacrylate (Denacol DM-811 manufactured by Nagase Sangyo Co., Ltd.), glycerol acrylate (Blenmer GAM manufactured by Nippon Oil & Fats Co., Ltd.), glycerol dimethacrylate ( Nippon Oil & Fats Bremer GMR), ECH-modified glycerol triacrylate (Nagase Sangyo Denacol DA-314), ECH-modified 1,6-hexanediol diacrylate (Nippon Kayaku Kayarad R-167), pentaerythritol triacrylate (Kayarad PET-30 manufactured by Nippon Kayaku Co., Ltd.), stearic acid-modified pentaerythritol diacrylate (Aronix M-233 manufactured by Toagosei Co., Ltd.), ECH-modified phthalic acid diacrylate (Denacol DA-721 manufactured by Nagase Sangyo Co., Ltd.), tri Glycerol diacrylate (Kyoeisha Yushi Co., Ltd. Poxyester 80 MFA).

The compound (b) having a dicyclopentadiene skeleton refers to, for example, a resin having a dicyclopentanyl skeleton, a dicyclopentenyl skeleton, or an adamantane skeleton. Among them, a dicyclopentanyl skeleton or a dicyclopentenyl skeleton is preferable in order to further improve wet heat durability. The durability of the compound having a dicyclopentadiene skeleton is improved even if at least one compound is contained in 100 parts by weight of the polymerizable resin composition, but it is preferably at least 10 parts by weight, more preferably It is preferable to contain 15 parts by weight or more, more preferably 20 parts by weight or more.

Examples of the compound having the dicyclopentanyl compound include dicyclopentanyl acrylate (FA-513A manufactured by Hitachi Chemical Co., Ltd.), dicyclopentanyl methacrylate (FA-513M manufactured by Hitachi Chemical Co., Ltd.), or dicyclopentanyl diacrylate. (Kayarad made by Nippon Kayaku Co., Ltd.
R-684). A resin having a dicyclopentanyl skeleton is most preferable.

Examples of the compound having a dicyclopentenyl skeleton include dicyclopentenyl acrylate (FA-511A manufactured by Hitachi Chemical Co., Ltd.), dicyclopentenyloxyethyl acrylate (FA-512A manufactured by Hitachi Chemical Co., Ltd.) or dicyclopentenyloxyethyl methacrylate ( Hitachi Chemical
FA-512M) is good.

Examples of the compound having an adamantane skeleton include 2-methyl-2-adamantyl methacrylate (Adamantate manufactured by Idemitsu Kosan Co., Ltd.).
MM), 2-ethyl-2-adamantyl methacrylate (Adamantate EM manufactured by Idemitsu Kosan Co., Ltd.), 3-hydroxy-1-adamantyl methacrylate (Adamantate HM manufactured by Idemitsu Kosan Co., Ltd.), 3-hydroxy-1-adamantyl acrylate (Adamantate HA manufactured by Idemitsu Kosan Co., Ltd.), 2-Methyl-2-adamantyl acrylate (Adamantate MA manufactured by Idemitsu Kosan) or 2-ethyl-2-adamantyl acrylate (Adamantate EA manufactured by Idemitsu Kosan) is preferable.

Among the (meth) acrylate compounds, there are resins that become (meth) acrylate compounds (A) and (meth) acrylate compounds (B). A compound satisfying both of these properties may be used as a (meth) acrylate compound (A) or a (meth) acrylate compound (B) depending on the properties of other compounds to be blended. Examples of such resins include pentaerythritol triacrylate (Kayarad PET-30 manufactured by Nippon Kayaku Co., Ltd.) and ECH-modified 1,6-hexanediol diacrylate (Kayarad R-167 manufactured by Nippon Kayaku Co., Ltd.).

In order to further improve the wet heat durability and the interlayer adhesion of the polarizing plate, the (meth) acrylate compound (B) has one or more hydroxyl groups and one or more (meth) acryloyl groups ( It has two components of (meth) acrylate compound (a) and (meth) acrylate compound (b) having a dicyclopentadiene skeleton and having at least one (meth) acryloyl group. More preferred. Each of them may be a single type, or a plurality of types of components may be mixed. A resin composition in which the content ratio of these two component (meth) acrylate compounds (a) and (b) is 5: 9 to 11: 3 is good, and the resin comprises the ratio of the (meth) acrylate compound (B). A polarizing plate having a layer obtained from the composition is further improved in durability.

In order to obtain a resin composition capable of improving the sufficiently stable hardness and durability of the polarizing plate, the compound having three or more (meth) acryloyl groups in (A) or (B) is a polymerizable resin composition. It is preferable to contain 50 parts by weight or more in 100 parts by weight of the product. More preferably 60 parts by weight or more, still more preferably 70 parts by weight or more.

The at least one (meth) acrylate compound (A) having two or more (meth) acryloyl groups is either a dicyclopentadiene skeleton, a pentaerythritol skeleton, a neopentyl glycol skeleton, a trimethylolpropane skeleton, or a dicyclopentadiene skeleton. Is more preferable because it can improve durability. As for the compound having any one of pentaerythritol skeleton, neopentyl glycol skeleton and trimethylolpropane skeleton, at least one kind is 30 parts by weight or more, preferably 5 parts by weight, more preferably 100 parts by weight of the polymerizable resin composition. It is preferable to contain 70 parts by weight.

Examples of the compound having a pentaerythritol skeleton include pentaerythritol triacrylate (Kayarad PET-30 manufactured by Nippon Kayaku Co., Ltd.) and pentaerythritol tetraacrylate (Kayarad manufactured by Nippon Kayaku Co., Ltd.).
PET-40), pentaerythritol tetramethacrylate (SR-367 manufactured by Sartomer), dipentaerythritol hexaacrylate (Kayarad DPHA manufactured by Nippon Kayaku Co., Ltd.), dipentaerythritol monohydroxypentaacrylate (manufactured by Sartomer)
SR-399), alkyl-modified dipentaerythritol pentaacrylate (Nippon Kayaku Kayrad D-310), alkyl-modified dipentaerythritol tetraacrylate (Nippon Kayaku Kayrad D-320), alkyl-modified dipentaerythritol triacrylate (Nippon Kayaku Kayrad D-330), caprolactone-modified dipentaerythritol hexaacrylate (Nippon Kayaku Kayrad DPCA-20, Nippon Kayaku Kayrad DPCA-60, Nippon Kayaku Kayrad DPCA-120) Further, stearic acid-modified pentaerythritol diacrylate (Aronix M-233 manufactured by Toa Gosei Co., Ltd.) is preferable. Preferably, pentaerythritol triacrylate (Kayarad PET-30 manufactured by Nippon Kayaku Co., Ltd.) is most preferable.

Examples of the compound having a neopentyl glycol skeleton include neopentyl glycol dimethacrylate (FA-125M, manufactured by Hitachi Chemical Co., Ltd.), neopentyl glycol diacrylate (Kayarat NPGDA, manufactured by Nippon Kayaku Co., Ltd.), neopentyl glycol diacrylate (Sartomer). SR-248), hydroxypivalate neopentyl glycol diacrylate (Nippon Kayaku Co., Ltd. Kayarad MANDA), caprolactone-modified hydroxypivalate neopentyl glycol diacrylate (Nippon Kayaku Co., Ltd. Kayarad HX series), alicyclic modification Neopentyl glycol acrylate (Kayarat R-629 manufactured by Nippon Kayaku Co., Ltd., Kayarad R-644 manufactured by Nippon Kayaku Co., Ltd.) or bis (acryloxyneopentyl glycol) adipate (Kayarad R-526 manufactured by Nippon Kayaku Co., Ltd.).

Examples of the compound having a trimethylolpropane skeleton include, for example, trimethylolpropane triacrylate (Kayarad TMPTA, manufactured by Nippon Kayaku Co., Ltd.), trimethylolpropane trimethacrylate (SR-350, manufactured by Sartomer), ditrimethylolpropane tetraacrylate (Sartomer). SR-355), neopentyl glycol modified trimethylolpropane diacrylate (Kayarad R-604 manufactured by Nippon Kayaku Co., Ltd.), EO modified trimethylolpropane triacrylate (SR-450 manufactured by Sartomer), PO modified trimethylolpropane triacrylate (Kayarad TPA-series manufactured by Nippon Kayaku Co., Ltd.) or ECH-modified trimethylolpropane triacrylate (Denar DA-321 manufactured by Nagase Sangyo Co., Ltd.).

When mixing at least one of the above compounds, the (meth) acrylate compound (A) is 30 parts by weight or more, more preferably 50 parts by weight or more in 100 parts by weight of the polymerizable resin composition excluding the solvent. More preferably, the content is 70 parts by weight or more. The (meth) acrylate compound (B) is preferably 10 parts by weight or more, more preferably 20 parts by weight or more, and still more preferably 30 parts by weight or more in 100 parts by weight of the polymerizable resin composition excluding the solvent. .

When the compound used in the present invention or the polymerizable resin composition thereof is polymerized by ultraviolet rays, a polymerization reaction is caused by using an ultraviolet polymerization initiator (C). Examples of the ultraviolet polymerization initiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 (Irgacure 907 manufactured by Ciba Specialty Chemicals), 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty). Irgacure 184 manufactured by Tea Chemicals), 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone (Irgacure 2959 manufactured by Ciba Specialty Chemicals), 1- (4-dodecylphenyl)- 2-hydroxy-2-methylpropan-1-one (Merck Darocur 953), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (Merck Darocur 1116), 2 -Hydroxy-2-methyl-1-fe Rupropan-1-one (Irgacure 1173 manufactured by Ciba Specialty Chemicals), acetophenone compounds such as diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy- Benzoin compounds such as 2-phenylacetophenone (Irgacure 651 manufactured by Ciba Specialty Chemicals), benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3 , 3′-dimethyl-4-methoxybenzophenone (Kayacure MBP manufactured by Nippon Kayaku Co., Ltd.) and the like, thioxanthone, 2- Chlorthioxanthone (Nippon Kayaku Co., Ltd. Kayacure CTX), 2-methylthioxanthone, 2,4-dimethylthioxanthone (Nippon Kayaku Co., Ltd. Kayacure RTX), isopropylthioxanthone, 2,4-diclothiothiol Thioxanes such as Sanson (Kayacure CTX manufactured by Nippon Kayaku Co., Ltd.), 2,4-diethylthioxanthone (Kayacure DETX manufactured by Nippon Kayaku Co., Ltd.), 2,4-diisopropylthioxanthone (Kayacure DITX manufactured by Nippon Kayaku Co., Ltd.) Compounds and the like. More preferably, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 (Irgacure 907 manufactured by Ciba Specialty Chemicals), 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals) Irgacure 184) or 2,2-dimethoxy-2-phenylacetophenone (Irgacure 651 manufactured by Ciba Specialty Chemicals) is preferable. These ultraviolet polymerization initiators (C) can be used singly or in combination at any blending ratio.

When a benzophenone compound or a thioxanthone compound is used, an auxiliary agent can be used in combination in order to accelerate the ultraviolet polymerization reaction. Examples of such auxiliaries include triethanolamine, methyldiethanolamine, triisopropanolamine, n-butylamine, N-methyldiethanolamine, diethylaminoethyl methacrylate, Michler's ketone, 4,4′-diethylaminophenone, 4-dimethylaminobenzoic acid. Examples include amine compounds such as ethyl, ethyl 4-dimethylaminobenzoate (n-butoxy) or isoamyl 4-dimethylaminobenzoate.

The addition amount of the ultraviolet polymerization initiator and the auxiliary agent is preferably used within a range where the polarization performance does not deteriorate, and the amount of the ultraviolet polymerization initiator is 100 parts by weight of the (meth) acrylate compound in the polymerizable composition. On the other hand, it is preferably 0.1 to 12 parts by weight, more preferably about 2 to 10 parts by weight. Further, the auxiliary agent is preferably about 0.5 to 2 times the amount of the ultraviolet polymerization initiator.

When the compound used in the present invention or the resin composition thereof is a thermosetting type, a polymerization initiator, a crosslinking agent and / or an initiation catalyst are used. As a kind of crosslinking agent, various well-known compounds, such as an isocyanate type, a boron type, a titanate type, can be used, and if it accelerates | stimulates polymerization, it will not be limited. The addition amount is 0.1 to 20 parts by weight in 100 parts by weight of the polymerizable resin composition, more preferably about 1 to 10 parts by weight in 100 parts by weight of the composition.

As a method for forming a polymerizable resin composition layer on a polarizing plate, for example, the composition is diluted directly or using an appropriate solvent, and a protective layer or a dichroic dye is adsorbed and oriented on a polyvinyl alcohol film. Apply. Thereafter, the solvent is removed by heating or the like, and a layer obtained by curing the polymerizable resin composition can be obtained by heating or irradiation with ultraviolet rays. The solvent of the solution of the composition used for coating is not particularly limited as long as it is excellent in solubility of the composition and wettability on the substrate during coating and does not cause deterioration in surface properties. Examples of such solvents include aromatic hydrocarbons such as toluene and xylene, ethers such as anisole, dioxane and tetrahydrofuran, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 3-pentanone, Ketones such as 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone or 2,6-dimethyl-4-heptanone, alcohols such as n-butanol, 2-butanol, cyclohexanol or isopropyl alcohol Cellosolves such as methyl cellosolve and methyl cellosolve, ethyl acetate, butyl acetate, methyl lactate, propylene glycol monomethyl ether acetate, propylene glycol ethyl ether acetate, methoxyacetate Esters such as Le or fence San ethoxyethyl, dimethyl sulfoxide, acetonitrile, N, including but N- dimethylacetamide dimethylformamide without limitation. Preferably, toluene, cyclopentanone or ethyl acetate is used. The solvent may be a single solvent or a mixture. The concentration of the composition at the time of dissolving the composition varies depending on solvent solubility, wettability on the substrate, thickness after coating, etc., but is preferably 5 to 95% by weight, more preferably 10 to 80% by weight. The degree is good.

In addition, when the wettability onto the substrate is poor or the surface property of the formed composition layer is poor when applied onto the substrate, various leveling levels are included in the composition in order to improve them. It is also possible to add an agent. As the type of the leveling agent, various compounds such as silicon-based, fluorine-based, polyether-based, acrylic acid copolymer-based or titanate-based compounds can be used. The addition amount is 0.0001 part by weight or more and 10 parts by weight or less in 100 parts by weight of the polymerizable resin composition, more preferably 0.1 part by weight or more and 5 parts by weight or less in 100 parts by weight of the composition. .

After the composition layer formed on the substrate is cured, if the adhesion between the cured layer and the protective film is poor, various crosslinking agents may be added to the composition in order to improve them. Is possible. As the type of the crosslinking agent, various compounds such as isocyanate, boron, titanate, or silicon can be used. The addition amount is 0.0001 part by weight or more and 20 parts by weight or less in 100 parts by weight of the polymerizable resin composition, more preferably 0.1 part by weight or more and 10 parts by weight or less in 100 parts by weight of the composition. .

As a method for forming a layer of a polymerizable resin composition on a polarizing plate, a resin layer may be provided by coating on a protective layer, or directly coated on a polyvinyl alcohol film adsorbed with a dichroic dye and boric acid. A layer may be provided by a method such as Or, it is not only applied to a protective layer or a polyvinyl alcohol film on which a dichroic dye is adsorbed and oriented, but also applied to another film in advance, and the cured layer is adsorbed and oriented on a protective layer or dichroic dye. A method of transferring or laminating to an alcohol film may also be used. Furthermore, the method of providing the adhesive layer as well as the method of providing the layer is also efficient, and furthermore, the polarizing plate can be most easily produced when the adhesive layer itself is a polymerizable resin composition. The application method is not particularly limited, and examples thereof include a spin coating method, a wire bar coating method, a gravure coating method, a micro gravure coating method, a calendar coating method, a spray coating method, a meniscus coating method, and the like.

It is preferable that the cured layer made of the polymerizable resin composition used in the present invention is sufficiently polymerized by heating or ultraviolet irradiation and has as little unreacted content as possible. The degree is 0 to 5 parts by weight of unreacted (meth) acrylate compound in 100 parts by weight of the cured resin composition, more preferably 0 to 3 parts by weight, and still more preferably 0 parts by weight. It is preferable that the amount be 1 part by weight or more. As a method for obtaining such a layer, for example, a method for optimizing the thickness of the layer of the resin composition after coating, a method for optimizing the kind and amount of the photopolymerization initiator to be added, sufficient heating or ultraviolet rays are used. A method of irradiating, a method of changing the atmosphere at the time of ultraviolet irradiation, such as performing in an inert gas such as nitrogen, and the like, can be mentioned. The simple method is the simplest because the method of optimizing the thickness of the resin layer can be optimized only by changing the resin concentration or changing the resin coating amount. The thickness of the layer obtained by curing the polymerizable resin composition is preferably 0.5 μm to 10 μm, more preferably 1 μm to 8 μm, still more preferably 2 μm to 6 μm. If it is thicker than 10 μm, the residual unreacted monomer increases, the wet heat durability is insufficient, and the polarizing plate turns red in the dry heat durability test, which is not suitable. On the other hand, a layer thinner than 0.5 μm does not lead to improvement in wet heat durability. Although the irradiation amount of an ultraviolet-ray changes with kinds of (meth) acrylate compound, the kind and addition amount of a photoinitiator, and a film thickness, for example, about 100-1500 mJ / cm < ² > is good. Thus, wet heat durability improves by providing the layer which consists of polymeric resin compositions in a polarizing plate.

Moreover, it is preferable that the layer which consists of polymeric resin compositions is transparent even if it processes with an alkaline solution. Specifically, one of the indicators is that there is no cloudiness after treatment with an alkaline aqueous solution of pH 11 or more at 40 ° C. for 10 minutes or more. As a standard, a film having a cured layer coated with a polyethylene resin terephthalate having a thickness of 5 μm and a cured layer was subjected to treatment at 40 ° C. for 10 minutes or more with an aqueous solution of pH 11 at a wavelength of 550 nm. The change of the light transmittance in is good within 5%, preferably within 1%. On the other hand, more preferably, the layer made of the polymerizable resin composition is treated with an alkaline aqueous solution, so that the layer made of the polymerizable resin composition improves adhesion to the polyvinyl alcohol film. In that case, the contact angle when 10 μl of water is dropped is preferably 60 ° or less, more preferably 50 ° or less, and still more preferably 40 ° or less. In the case of bonding to a polarizing element film, it is preferable to use a solution to which neutralization treatment is performed with water or an acidic aqueous solution after treatment with an alkaline aqueous solution, followed by drying treatment.

A method for producing the polarizing plate may be a known method and is not limited. Specifically, the hydrophilic polymer film (hereinafter referred to as a polarizing element film) that has been adsorbed and stretched by adsorbing a dichroic dye is obtained by providing at least one protective layer. Examples of the hydrophilic polymer film include a polyvinyl alcohol resin, an amylose resin, a starch resin, a cellulose resin, and a polyacrylate resin, and those obtained by forming these resins by casting or the like are used. . The type of polarizing element film includes a uniaxially stretched film adsorbed with a dichroic material such as iodine or a dichroic dye, and a polyene-based oriented film made of polyvinyl alcohol dehydrated or polyvinyl chloride dehydrochlorinated. But it ’s okay. Among these, a polarizing element film made of a polyvinyl alcohol resin film and a dichroic substance such as iodine is preferable. The thickness of these polarizing elements is not particularly limited, but is generally about 5 to 80 μm.

The manufacturing method of the polyvinyl alcohol-type resin which comprises a polarizing element film can be produced by a well-known method, and is not specifically limited. As a production method, for example, it can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids. The saponification degree of the polyvinyl alcohol resin is usually preferably from 85 to 100 mol%, more preferably 95 mol% or more. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. Moreover, 1,000-10,000 are preferable normally and the polymerization degree of polyvinyl alcohol-type resin has more preferable 1,500-5,000. What formed the polyvinyl alcohol-type resin into a film is used as a polyvinyl alcohol-type film.

The obtained polyvinyl alcohol film is dyed with a dichroic substance such as iodine and uniaxially stretched to produce a polarizing element film. As a production method, for example, it can be produced by dyeing a polyvinyl alcohol-based resin film by immersing it in an iodine aqueous solution and stretching it 2 to 7 times the original length. You may immerse in aqueous solutions, such as a boric acid and potassium iodide, as needed. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol film with water, dirt and plasticizers on the surface of the polyvinyl alcohol film can be removed, and the effect of preventing unevenness such as uneven dyeing by swelling the polyvinyl alcohol film. There is also. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched even in an aqueous solution of boric acid or potassium iodide.

Polyvinyl alcohol film is not only dichroic dye, but also boron compounds such as boric acid, borax or ammonium borate, polyvalent aldehyde such as glyoxal or glutaraldehyde, dialdehyde starch, biuret type, isocyanurate type or block Type polyvalent isocyanate compounds, titanium compounds such as titanium oxysulfate, ethylene glycol glycidyl ether, polyamide epichlorohydrin, succinic peroxide, ammonium persulfate, calcium perchlorate, benzoin ethyl ether, ethylene glycol diglycidyl ether or You may contain at least 1 or more types of crosslinking agents, such as glycerol diglycidyl ether, or a water-resistant agent. If an appropriate concentration of the boric acid content is shown, it is preferably 10 to 33% by weight, preferably 18 to 30% by weight, more preferably 20 to 26% by weight based on the weight% of the polyvinyl alcohol film. That is good.

Moreover, the polyvinyl alcohol film may contain an alkali metal, an alkaline earth metal, a halide, or an inorganic metal. Substances to be treated include, for example, potassium iodide, sodium iodide, ammonium iodide, cobalt iodide, zinc iodide, zinc chloride, potassium chloride or sodium chloride, zinc fluoride tetrahydrate, aluminum chloride, fluoride. Aluminum fluoride, ammonium fluoride, potassium fluoride, potassium fluoride fluoride, titanium titanium fluoride, calcium fluoride, chromium fluoride trihydrate, potassium zirconium fluoride, ammonium hydrogen fluoride, sodium hydrogen fluoride, fluoride Examples include potassium hydrogen, hydrofluoric acid, tin fluoride, strontium fluoride, cesium fluoride, lead fluoride, barium fluoride, magnesium fluoride, lanthanum ammonium chloride, or magnesium chloride, but are particularly limited. It is not a thing. One or more kinds of halogen ions or inorganic metal ions contained in the substances shown above may be contained.

The obtained polarizing element film is preferably provided with a transparent protective layer on at least one surface or both surfaces thereof. The transparent protective layer can be formed by coating with a polymer, or can be provided as a laminate layer of a film. The transparent polymer or film forming the transparent protective layer is preferably a transparent polymer or film having high mechanical strength and good thermal stability. Examples of substances used as the transparent protective layer include cellulose acetate resins such as triacetyl cellulose and diacetyl cellulose or films thereof, acrylic resins or films thereof, polyvinyl chloride resins or films thereof, polyester resins or films thereof, polyarylate resins or The film, a cyclic polyolefin resin having a cyclic olefin such as norbornene or the film thereof, polyethylene, polypropylene, a polyolefin having a cyclo or norbornene skeleton or a copolymer thereof, and the main chain or side chain of which is imide and / or amide Examples thereof include a resin, a polymer, or a film thereof. A resin having liquid crystallinity or a film thereof may be provided. The thickness of the protective film is, for example, about 0.5 to 200 μm. A polarizing plate is preferably prepared by providing one or more layers of the same or different types of resins or films on one or both sides.

In providing a transparent protective layer on a polarizing element film, when the protective layer is a film, it is necessary to perform film lamination. In that case, an adhesive is required. As the adhesive, a resin composition containing at least one kind of resin having any of a dicyclopentanyl skeleton, a dicyclopentenyl skeleton, a pentaerythritol skeleton, a neopentyl glycol skeleton, or a trimethylolpropane skeleton is preferable. Although the layer which hardened | cured was good, it is not limited, A well-known adhesive agent can be used. When one or more layers obtained by curing the polymerizable resin composition are provided on the surface of the protective layer not in contact with the adhesive layer or between the protective layer and the adhesive layer, the protective layer and the polarizing element film, or the polymerizable layer, respectively. The layer obtained by curing the resin composition is bonded to the polarizing element film, and a polyvinyl alcohol-based adhesive can be used as an adhesive in that case. Examples of the polyvinyl alcohol-based adhesive include Gohsenol NH-26 (manufactured by Nihon Gosei Co., Ltd.), Exeval RS-2117 (manufactured by Kuraray Co., Ltd.), and Goose Famer Z-200 (manufactured by Nihon Gosei Co., Ltd.). It is not limited. You may add crosslinking agents and / or water-proofing agents, such as a cryoxal and glutaraldehyde, to an adhesive agent. The adhesive preferably contains an acid substance such as sulfuric acid, acetic acid, hydrochloric acid, formic acid, aluminum sulfate or aluminum chloride at a concentration of 0.0001 to 20% by weight, and contains 0.02 to 5% by weight. More preferably. As the polyvinyl alcohol-based adhesive, an adhesive in which only a maleic anhydride-isobutylene copolymer / and a crosslinking agent are mixed can be used. As maleic anhydride-isobutylene copolymers, for example, isoban # 18 (manufactured by Kuraray), isoban # 04 (manufactured by Kuraray), ammonia-modified isoban # 104 (manufactured by Kuraray), ammonia-modified isoban # 110 (manufactured by Kuraray) ), Imidized isoban # 304 (manufactured by Kuraray), imidized isoban # 310 (manufactured by Kuraray), and the like. A water-soluble polyvalent epoxy compound can be used as the crosslinking agent at that time. Examples of the water-soluble polyvalent epoxy compound include Denacol EX-521 (manufactured by Nagase Chemtech) and Tetrat-C (manufactured by Mitsui Gas Chemical Co., Ltd.). As other adhesives, urethane-based, acrylic-based, and epoxy-based adhesives are frequently used, and known adhesives can be used, but the adhesive is not limited. Further, as an additive for the adhesive, a zinc compound, chloride, iodide and the like can be simultaneously contained at a concentration of about 0.1 to 10% by weight. The additive is not limited. After laminating the transparent protective layer with an adhesive, the polarizing plate is obtained by drying or heat treatment at a suitable temperature.

In the case where a layer obtained by curing the polymerizable resin composition is provided on the polarizing plate, it is composed of protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer. The durability can be improved by providing one or more layers between or on any of the polarizing plates. Specifically, one layer is provided on any of the surface of the protective layer not facing the adhesive layer, between the protective layer and the adhesive layer, or between the adhesive layer and the polyvinyl alcohol-based film on which the dichroic dye is adsorbed and oriented. This is achieved by providing the above. In order to further improve the wet heat durability, it is effective to provide a layer obtained by curing the polymerizable resin composition on the surface side that becomes the exposed surface after being bonded to the display device. Specifically, it shows the surface of the protective layer (L), between the protective layer (L) and the adhesive layer (L), and between the adhesive layer (L) and the polarizing element film. Preferably, the space between the protective layer (L) and the adhesive layer (L) and the space between the adhesive layer (L) and the polarizing element film are preferable. Further, in order to further enhance the wet heat durability improving effect, a layer obtained by curing the resin composition is provided on both surfaces one by one or two or more layers through a polyvinyl alcohol film on which a dichroic dye is adsorbed and oriented. It is more preferable. Moreover, it is preferable to have it in the layer close | similar to a polarizing element film in that case in order to improve durability further. Specifically, it is preferably provided on both surfaces between the protective layer (L) and the polarizing element film and between the polarizing element film and the protective layer (M). In addition, for the purpose of improving adhesion or in order to prevent migration of unreacted monomers of the polymerizable resin composition, an anchor coat layer and / or a layer between the polarizing element film and the layer obtained by curing the polymerizable resin composition are used. Alternatively, an adhesive layer may be provided.

Similarly, even if the adhesive layer of the polarizing plate composed of a protective layer / adhesive layer / polyvinyl alcohol film / adhesive layer / protective layer adsorbed and oriented with a dichroic dye is a layer obtained by a polymerizable resin composition The effect of improving wet heat durability is obtained.

When trying to obtain a polarizing plate having high durability in a wet heat test, not only one layer obtained by curing the polymerizable resin composition but also a multilayer structure of two or more layers. Thus, the wet heat durability is further improved.

The polarizing plate characterized by providing at least one layer obtained by curing the polymerizable resin composition used in the present invention by the above steps is obtained.

Various functional layers and / or pressure-sensitive adhesive layers can also be provided on one surface of the obtained polarizing plate, specifically, the surface of a protective layer or film that becomes a non-exposed surface after being bonded to a display device. By providing the pressure-sensitive adhesive layer, a polarizing plate can be attached to a display device such as various functional layers, liquid crystal, or organic electroluminescence. The various functional layers may be layers or films for controlling the phase difference.

This polarizing plate has an antireflection layer, an antiglare layer, a hard coat layer, a liquid crystal coating for improving the viewing angle and / or contrast on the exposed surface of the cured layer, protective layer or film of the polymerizable resin composition. You may have various well-known functional layers, such as a construction layer. A coating method is preferable for producing the layer having various functions, but a film having the function may be bonded via an adhesive or a pressure-sensitive adhesive.

By the above method, the polarizing plate of this invention which has a ultraviolet curable resin composition and the layer which hardened it can be obtained. The polarizing plate obtained according to the present invention is a polarizing plate with little change in transmittance and lowering of the degree of polarization at a temperature of 65 ° C. and a relative humidity of 93% RH in a humid heat environment. The number of polarizing plates is small, and a highly reliable polarizing plate can be obtained even under severe conditions. A polarizing plate for display, particularly a polarizing plate with high transmittance, high contrast, and high wet heat durability in a liquid crystal display can be obtained. A display using this is a display having high reliability, long-term high contrast, and high color reproducibility.

A polarizing plate provided with a layer obtained by curing the polymerizable resin composition can suppress a decrease in the degree of polarization of the polarizing plate in a humid heat environment, for example, at a temperature of 65 ° C. and a relative humidity of 93% RH. The decrease can be suppressed. Wet heat durability is improved by suppressing a decrease in boric acid concentration in a humid heat environment. The decrease in boric acid concentration is preferably maintained at 40% by weight or more, more preferably 55% by weight or more, more preferably 70% after the initial boric acid concentration at 65 ° C. and 93% relative humidity after 1000 hours. It is preferable to hold at least% by weight.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these. In addition, the transmittance | permeability and polarization degree which are shown to an Example were performed as follows.

The transmittance when the two polarizing plates obtained by bonding the protective films on both sides of the polarizing element film are stacked so that the absorption axis directions are the same is the parallel transmittance Tp, and the two polarizing plates The transmittance when the absorption axes are stacked so that the absorption axes are orthogonal to each other is defined as the orthogonal transmittance Tc.

The transmittance T was calculated from the following formula (1) by obtaining the spectral transmittance τλ at predetermined wavelength intervals dλ (here, 5 nm) in the wavelength region of 400 to 700 nm. In the equation, Pλ represents a spectral distribution of standard light (C light source), and yλ represents a 2 ° visual field color matching function.

Spectral transmittance τλ was measured using a spectrophotometer (“U-4100” manufactured by Hitachi, Ltd.).

The degree of polarization Py was determined by the following formula (2) from the parallel transmittance Tp and the orthogonal transmittance Tc.

Py = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100 (2)

Furthermore, in the color system shown by JIS Z8729 (color display method L *, a *, b * display system and L *, u *, v * color system) about the hue of the polarizing plate, a * and b * were measured. The term “orthogonal hue” as used herein means that the measurement was performed in a state where two polarizing plates were overlapped so that their absorption axes were orthogonal to each other. In the L *, a *, and b * color systems, the hues indicate neutral colors as a * and b * are closer to zero.

Comparative Example 1
A polyvinyl alcohol film (VF-XS manufactured by Kuraray Co., Ltd.) having a thickness of 75 μm, a polymerization degree of 2400, and a saponification degree of 99% or more was swollen with warm water at 40 ° C., and then an aqueous solution containing iodine, potassium iodide and boric acid. Staining was performed. The dyed film was stretched 5 times in a solution containing 3% by weight of boric acid, and after being stretched, it was immersed in an aqueous solution containing 5% by weight of potassium iodide. A film immersed in an aqueous potassium iodide solution for 15 seconds was dried with a dryer at 70 ° C. for 10 minutes to obtain a polarizing element film. The obtained polarizing element film was obtained by laminating a triacetyl cellulose film (TD-80UF manufactured by Fuji Photo Film Co., Ltd., hereinafter abbreviated as TAC) on both sides as a protective layer using a PVA adhesive.

Next, 50 parts by weight of dipentaerythritol hexaacrylate (Kayarad DPHA manufactured by Nippon Kayaku Co., Ltd.), 50 parts by weight of pentaerythritol triacrylate (Kayarad PET-30 manufactured by Nippon Kayaku Co., Ltd.), Irgacure 184 (manufactured by Ciba Specialty Chemicals) 5 parts by weight of the mixture was stirred and mixed to obtain an ultraviolet curable polymerizable resin composition used in the present invention. This composition was diluted with methyl ethyl ketone (manufactured by Junsei Chemical Co., Ltd.) to prepare a solution having a solid content concentration of 50% by weight. This solution was applied to the surface of a polarizing plate cut into 40 mm × 40 mm and bonded to a 1 mm glass plate via an adhesive PTR-3000 (manufactured by Nippon Kayaku Co., Ltd.) using a spin coater, and the solvent was removed by heating. The film thickness was set to 3 μm. The solvent was dried at 50 ° C. for 3 minutes, and then irradiated with a high-pressure mercury lamp (integrated light amount 400 mJ / cm ² ) in the air and cured to obtain a polarizing plate of the present invention having a layer obtained from the polymerizable resin composition. . The layer structure of the sample is a structure obtained by the polymerizable resin composition / TAC / adhesive layer / polarizing element film / adhesive layer / TAC / adhesive layer / glass layer.

The produced sample was confirmed to be a wet heat test and a dry heat test. In the wet heat test, the transmittance and polarization degree were measured before and after leaving for 1000 hours in an atmosphere of a temperature of 65 ° C. and a relative humidity of 93%. In the dry heat test, the transmittance, polarization degree, and orthogonal hue a * (hereinafter abbreviated as a * -c) before and after leaving at a temperature of 95 ° C. for 1000 hours were measured.

Comparative Example 2
In Comparative Example 1 , the polymerizable resin composition was changed to pentaerythritol triacrylate (Kayarad manufactured by Nippon Kayaku Co., Ltd.).
In addition to 60 parts by weight of PET-30, 30 parts by weight of dicyclopentenylethyl methacrylate (FA-512M manufactured by Hitachi Chemical Co., Ltd.), and 5 parts by weight of Irgacure 184 (manufactured by Ciba Specialty Chemicals), a dicyclopentenyl skeleton is included. A polarizing plate was prepared in the same manner except that the polarizing plate of the present invention having a layer obtained from the polymerizable resin composition was obtained, and durability in a wet heat test and a dry heat test was confirmed.

Comparative Example 3
In Comparative Example 1, the polymerizable resin composition was mixed with 50 parts by weight of dipentaerythritol hexaacrylate (Kayarad DPHA manufactured by Nippon Kayaku Co., Ltd.) and pentaerythritol triacrylate (Kayarad manufactured by Nippon Kayaku Co., Ltd.).
PET-30) 30 parts by weight, dicyclopentanyl acrylate (FA-513A manufactured by Hitachi Chemical Co., Ltd.) 20 parts by weight, Irgacure 184 (manufactured by Ciba Specialty Chemicals) 5 parts by weight, obtained by a polymerizable resin composition A polarizing plate was prepared in the same manner except that the polarizing plate of the present invention having a layer to be obtained was obtained, and durability in a wet heat test and a dry heat test was confirmed.

Example 1
Triacetyl cellulose film (TD-80UF manufactured by Fuji Photo Film Co., Ltd.), 50 parts by weight of dipentaerythritol hexaacrylate (Kayarad DPHA manufactured by Nippon Kayaku Co., Ltd.), pentaerythritol triacrylate (Kayarad manufactured by Nippon Kayaku Co., Ltd.)
30 parts by weight of PET-30), 20 parts by weight of dicyclopentanyl acrylate (manufactured by Hitachi Chemical Co., Ltd. FA-513A) and 5 parts by weight of Irgacure 184 (manufactured by Ciba Specialty Chemicals) are coated to a thickness of 3 μm. Then, ultraviolet rays were irradiated in the air with a high-pressure mercury lamp (integrated light amount 400 mJ / cm ² ) to produce a transparent protective film having a layer obtained from the polymerizable resin composition. The surface of the layer was brought into contact with an alkaline aqueous solution of pH 11 for 10 minutes, and the contact angle with water on the surface of the layer was reduced from 80 ° to 57.2 °. The layer obtained by curing the polymerizable resin composition is adhered to the polarizing element using an adhesive, and the structure is a layer obtained by curing the TAC / polymerizable resin composition / adhesive layer / polarizing element film / adhesive layer. A polarizing plate having / TAC was obtained. Layer / adhesive layer / polarized light in which the polarizing plate is cut into 40 mm × 40 mm and bonded to a 1 mm glass plate via an adhesive (PTR-3000 manufactured by Nippon Kayaku Co., Ltd.), and the TAC / polymerizable resin composition is cured. The wet heat test and dry heat durability were confirmed with the constitution of base film / adhesive layer / TAC / adhesive layer / glass.

Example 2
In Example 1 , a layer obtained by curing the polymerizable resin composition was provided on both sides of the polarizing element film, and a layer obtained by curing the TAC / polymerizing resin composition / adhesive layer / polarizing element film / adhesive layer / polymerization. A sample was prepared in the same manner except that a polarizing plate having a configuration of curable resin composition / layer / TAC was obtained, and a wet heat test and a dry heat test were confirmed.

Comparative Example 4
In Comparative Example 3 , a sample was prepared in the same manner except that the film thickness after removal of the solvent by heating was 1 μm and cured to obtain a polarizing plate having a layer obtained from the polymerizable resin composition of the present invention. The wet heat test and the dry heat test were confirmed.

Comparative Example 5
In Comparative Example 3 , a sample was prepared in the same manner except that the film thickness after removal of the solvent by heating was 9 μm and cured to obtain a polarizing plate having a layer obtained from the polymerizable resin composition of the present invention. The wet heat test and the dry heat test were confirmed.

Comparative Example 6
In Comparative Example 1 , the durability in the wet heat test and the dry heat test was confirmed in the same manner except that the layer obtained from the polymerizable resin composition was not provided.

Comparative Example 7
In Comparative Example 1 , the polymerizable resin composition was stirred and mixed with 100 parts by weight of dipentaerythritol hexaacrylate (Kayarad DPHA manufactured by Nippon Kayaku Co., Ltd.) and 5 parts by weight of Irgacure 184 (manufactured by Ciba Specialty Chemicals). The durability in the wet heat test and the dry heat test was confirmed in the same manner except that a layer made of a polymerizable resin composition not satisfying the above condition was provided on the polarizing plate.

Comparative Example 8
In Comparative Example 1 , the polymerizable composition was mixed with 50 parts by weight of polyethylene glycol diacrylate (Kayarad PEG-400DA manufactured by Nippon Kayaku Co., Ltd.), 50 parts by weight of pentaerythritol triacrylate (Kayarad PET-30 manufactured by Nippon Kayaku Co., Ltd.), Irgacure 184 (manufactured by Ciba Specialty Chemicals) was mixed with stirring, and the wet heat test and the dry heat test were similarly performed except that a layer made of a polymerizable resin composition not satisfying the conditions of the present invention was provided on the polarizing plate. The durability was confirmed.

Comparative Example 9
In Comparative Example 1 , the film thickness after removal of the solvent by heating was 20 μm, and after drying the solvent, it was cured by irradiating it with a high-pressure mercury lamp (integrated light amount 400 mJ / cm ² in air). A polarizing plate was prepared in the same manner except that a polarizing plate having a layer thickness obtained from the polymerizable resin composition not satisfying the above conditions, and durability in a wet heat test and a dry heat test was confirmed.

Comparative Example 10
According to Comparative Example 1 of JP-A-2003-185842, iodine and boric acid are adsorbed on a polyvinyl alcohol film, and dicyclopentenyloxyethyl methacrylate (FA-512M manufactured by Hitachi Chemical Co., Ltd.) is 100 weights on the surface of the polarizing element film stretched 5 times. Part, D1173 (polymerization initiator made by Merck & Co., Inc.) 5 parts by weight is coated so that the thickness of the polymerizable cured product layer is 20 μm, and is obtained by curing with a metal halide lamp by irradiating ultraviolet rays at 400 mJ / m ^2. A plate was prepared, and durability in a wet heat test and a dry heat test was confirmed.

Comparative Example 11
In Comparative Example 3 , the sample was similarly obtained except that the film thickness after removal of the solvent by heating was 0.3 μm and cured to obtain a polarizing plate having a layer obtained by the polymerizable resin composition of the present invention. Fabrication was performed and a wet heat test and a dry heat test were confirmed.

Table 3 shows the measurement results of wet heat test 65 ° C., relative humidity 93%, transmittance after 1000 hours, and change in polarization degree in Examples 1 and 2 and Comparative Examples 1 to 11 . In Table 3, Ys0 is the initial transmittance, ρ0 is the initial polarization degree, Ys-Wet is the transmittance after 65 ° C. × 93% RH × 1000 hours, ρ-Wet is the transmittance after 65 ° C. × 93% RH × 1000 hours, and ΔYs is 65 from the beginning. The amount of change in transmittance after 1000 hours at 1000 ° C. × 93% RH, and Δρ represents the amount of change in polarization degree after 1000 hours from 65 ° C. × 93% RH from the beginning. Moreover, the result of having confirmed the adhesiveness of each layer after 65 degreeC x 93% RHx1000 time progress is shown. As a result of adhesion, ◯ indicates that the mutual layers have good adhesion, and X indicates that there is an interlayer to be peeled off.

Table 3

Table 4 shows the measurement results of transmittance and change in polarization degree after 1000 hours at 95 ° C. in the dry heat test in Examples 1 and 2 and Comparative Examples 1 to 11 . In Table 4, Ys0 is the initial transmittance, ρ0 is the initial polarization degree, a * -c0 is the initial a * -c value, Ys1000 is the transmittance after 95 ° C. × 1000 hours, ρ1000 is the polarization degree after 95 ° C. × 1000 hours, a * -c1000 indicates a * -c after 95 ° C. × 1000 hours. The higher the a * -c value, the more red the color is.

Table 4

As is clear from the above Examples and Comparative Examples, the solvent is removed from the polarizing plate using the polarizing element film obtained from the hydrophilic polymer obtained by adsorbing and stretching the dichroic dye and the crosslinking agent of the present invention. In 100 parts by weight of the polymerizable resin composition, the moisture permeability of the resin film layer is 1500 g / m in 24 hours when the cured resin film layer is a (meth) acrylate compound having two or more acryloyl groups and has a film thickness of 5 μm. 30 to 98 parts by weight of at least one (meth) acrylate compound (A) of ² or less, and at least one (meth) acrylate compound (B) having a solubility in water of 25 ° C. of 1% by weight or less. ) Has a layer obtained by curing a polymerizable resin composition containing 1 to 70 parts by weight and 2 to 10 parts by weight of a polymerization initiator (C), and the thickness of the layer is 0.5 to 10 μm. A layer at least A polarizing plate being provided above the layer, durability, mainly improved wet heat durability is large and it can be seen that the polarizer does not occur color change in the dry heat durability. For example, the durability at 65 ° C. and 93% relative humidity is improved, the change in transmittance and the decrease in the polarization degree are suppressed, and the decrease in the polarization degree is small and the redness is small in the dry heat test, for example, 95 ° C. It was shown to be a polarizing plate. However, when the thickness of the layer of the polymerizable resin composition is 10 μm or more, dry heat durability, for example, the decrease in the degree of polarization is large at 95 ° C., the redness of the polarizing plate is large, and the durability It turns out that it is insufficient. From the above, the polarizing plate obtained by the present invention has greatly improved wet heat durability and has become a polarizing plate in which no color change occurs even in a dry heat test.

Claims (4)

A polarizing plate using a polarizing element film obtained from a stretched hydrophilic polymer that adsorbs a dichroic dye and a crosslinking agent,
(1) A (meth) acrylate compound having two or more (meth) acryloyl groups, which is dipentaerythritol hexaacrylate , and the resin film layer has a moisture permeability of 24 when it is a cured resin film layer having a thickness of 5 μm. 50 parts by weight of at least one (meth) acrylate compound (A) that is 1500 g / m ² or less in time,
A (meth) acrylate compound having two or more (meth) acryloyl groups, which is pentaerythritol triacrylate, and at least one (meth) acrylate compound (B) having a solubility in water at 25 ° C. of 1% by weight or less ) Is 50 parts by weight,
A layer obtained by curing a polymerizable resin composition containing 5 parts by weight of a polymerization initiator (C) ;
Or
(2) A (meth) acrylate compound having two or more (meth) acryloyl groups, which is pentaerythritol triacrylate, and the moisture permeability of the resin film layer in the case of a cured resin film layer having a film thickness of 5 μm is 24 hours. 60 parts by weight of at least one (meth) acrylate compound (A) that is 1500 g / m ² or less at
A (meth) acrylate compound having two or more (meth) acryloyl groups which is dicyclopentenylethyl methacrylate, and having at least one (meth) acrylate compound having a solubility in water at 25 ° C. of 1% by weight or less ( B) is 30 parts by weight,
Having a layer obtained by curing a polymerizable resin composition containing 5 parts by weight of a polymerization initiator (C);
Or
(3) A (meth) acrylate compound having two or more (meth) acryloyl groups, which is dipentaerythritol hexaacrylate, having a moisture permeability of 24 when the cured resin film layer has a thickness of 5 μm. 50 parts by weight of at least one (meth) acrylate compound (A) that is 1500 g / m ² or less in time ,
A (meth) acrylate compound having two or more (meth) acryloyl groups, which is pentaerythritol triacrylate, has a moisture permeability of 1500 g / 24 hours in a cured resin film layer having a thickness of 5 μm. 30 parts by weight of at least one (meth) acrylate compound (A) that is m ² or less,
(Meth) acrylate compound having two or more (meth) acryloyl groups, which is dicyclopentanyl acrylate, and having at least one (meth) acrylate compound having a solubility in water at 25 ° C. of 1% by weight or less ( B) is 20 parts by weight,
It has a layer obtained by curing a polymerizable resin composition containing 5 parts by weight of a polymerization initiator (C), the thickness of the layer is 0.5 to 10 μm, and the polymerizable resin composition is cured. At least one layer is provided between the protective layer and the polarizing element film in the protective layer / adhesive layer / polarizing element film / adhesive layer / protective layer structure in the laminated structure of the polarizing plates when the layer is provided. A polarizing plate characterized by. In the polarizing plate in which the layer obtained by curing the polymerizable resin composition is constituted by a protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer, the polarizing plate according to claim 1, characterized in that provided at least one layer between the protective layer (L) and a polarizing Motomaku. In the polarizing plate in which the layer obtained by curing the polymerizable resin composition is constituted by a protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer, between the protective layer (L) and the adhesive layer (L), the polarizing plate according to claim 1 or 2, characterized in that provided at least one layer. In the polarizing plate constituted by the protective layer (L) / adhesive layer (L) / polarizing element film / adhesive layer (M) / protective layer (M) / adhesive layer, the layer obtained by curing the polymerizable resin composition is: At least one or more layers are provided between the protective layer (L) and the adhesive layer (L) and between the protective layer (M) and the adhesive layer (M). The polarizing plate as described in any one of Claims 1 thru | or 3 .