JP7403584B2 - Polarizing film and its manufacturing method - Google Patents

Description

The present invention relates to a polarizing film in which a first resin layer, a polarizer, an alignment film, and a second resin layer are laminated in this order, and a method for manufacturing the same.

Polarizing films and the like are used in flat panel display devices (FPD). Such polarizing films include polarizers in which dichroic dyes such as iodine are aligned and adsorbed onto a polyvinyl alcohol resin film, as well as polarizers obtained by applying and polymerizing a polymerizable liquid crystal compound onto a base material. film is known. For example, Patent Document 1 discloses a polarizing film having dye diffusion prevention layers on both sides of a polarizer containing a polymer of a polymerizable liquid crystal compound and a dichroic dye.

JP2017-083843A

However, according to the inventor's study, in such a polarizing film, since the dye diffusion prevention layer (resin layer) is formed of a water-soluble resin with a polarity different from that of the hydrophobic polymerizable liquid crystal, each layer It was found that the compatibility at the interface was not sufficient and there were cases where sufficient adhesion was not obtained.

Therefore, an object of the present invention is to provide a polarizing film with excellent interlayer adhesion and a method for manufacturing the same.

As a result of intensive studies to solve the above problems, the present inventors have discovered that a polarizing film in which a first resin layer, a polarizer, an alignment film, and a second resin layer are laminated in this order. The present inventors have discovered that the above problems can be solved by forming the alignment film, and the second resin layer with a cured product of a composition containing a compound having a (meth)acryloyl group, and have completed the present invention. That is, the present invention includes the following aspects.

[1] A polarizing film in which a first resin layer, a polarizer, an alignment film, and a second resin layer are laminated in this order,
The first resin layer is a cured product of a first curable composition containing a (meth)acrylic compound,
The polarizer is a cured product of a polarizer-forming composition containing a polymerizable liquid crystal compound having a (meth)acryloyl group and a dichroic dye,
The alignment film is a cured product of a composition for forming an alignment film containing a (meth)acrylic compound,
The second resin layer is a polarizing film that is a cured product of a second curable composition containing a (meth)acrylic compound.
[2] The polarizing film according to [1], wherein at least one of the first curable composition and the second curable composition contains a radical polymerization initiator.
[3] The polarizing film according to [1] or [2], wherein at least one of the first curable composition and the second curable composition contains a urethane (meth)acrylate compound as the (meth)acrylic compound.
[4] The polarizing film according to [3], wherein the urethane (meth)acrylate compound has a number of (meth)acryloyl groups per unit molecular weight of 15×10 ⁻⁴ or more.
[5] At least one of the first curable composition and the second curable composition contains a polyfunctional (meth)acrylate compound as the (meth)acrylic compound, according to any one of [1] to [4]. polarizing film.
[6] The polarizing film according to [5], wherein the number of (meth)acryloyl groups in the polyfunctional (meth)acrylate compound is 6 or more.
[7] The polyfunctional (meth)acrylate compound has a branched structure, and the number of atoms in the chain connecting the branch point closest to the (meth)acryloyl group in the branched structure and the (meth)acryloyl group is 3 or less, the polarizing film according to [5] or [6].
[8] Applying or superimposing the first curable composition on the polarizer surface of the laminate in which the second resin layer, the alignment film, and the polarizer are laminated in this order, and curing the first curable composition. The method for producing a polarizing film according to any one of [1] to [7], including the step.
[9] The first curable composition formed on the release film is superimposed on the polarizer surface of the laminate in which the second resin layer, the alignment film, and the polarizer are laminated in this order, and the release film is formed. By curing the first curable composition by irradiating active energy rays from the side, a laminate in which a release film, a first resin layer, a polarizer, an alignment film, and a second resin layer are laminated in this order is formed. The method for producing a polarizing film according to any one of [1] to [7], which includes the step of peeling a release film from the laminate.

The polarizing film of the present invention has excellent interlayer adhesion.

1 is a schematic cross-sectional view of the layer structure of a polarizing film with a front plate, which is one embodiment of the present invention. 1 is a schematic cross-sectional view of the layer structure of a polarizing plate with a front plate, which is one embodiment of the present invention. 1 is a schematic cross-sectional view of the layer structure of a polarizing film with a front plate, which is one embodiment of the present invention. 1 is a schematic cross-sectional view of the layer structure of a polarizing plate with a front plate, which is one embodiment of the present invention.

[Polarizing film]
In the polarizing film of the present invention, a first resin layer, a polarizer, an alignment film, and a second resin layer are laminated in this order. The first resin layer is a cured product of a first curable composition containing a (meth)acrylic compound, and the polarizer is a polarizer-forming polarizer containing a polymerizable liquid crystal compound having a (meth)acryloyl group and a dichroic dye. The alignment film is a cured product of the composition, the alignment film is a cured product of the composition for forming an alignment film containing a (meth)acrylic compound, and the second resin layer is a cured product of the second curable composition containing the (meth)acrylic compound. It is a thing. In this way, the polarizing film of the present invention has each layer composed of a cured product of a composition containing a compound having a (meth)acryloyl group, that is, the polarizing film contains a polymer of a compound having a (meth)acryloyl group. Because of this structure, the compatibility of each layer interface is high, and excellent adhesion between layers can be exhibited.

<Polarizer>
The polarizer included in the polarizing film of the present invention is formed on the surface of the alignment film opposite to the second resin layer. The polarizer is a cured product of a polarizer-forming composition containing a polymerizable liquid crystal compound having a (meth)acryloyl group and a dichroic dye. In such polarizers, the dichroic dye is included in the polymerizable liquid crystal compound, and the polymerizable liquid crystal compound and the dichroic dye are polymerized and cured in an oriented state. Compared to a polarizer in which a dichroic dye is adsorbed and oriented on an alcohol-based resin film, the dichroic dye is less likely to be retained in the polymer component, and the dichroic dye is transferred from the polarizer to the first resin in high-temperature environments. or the second resin layer, which tends to cause a decrease in polarization performance over time. In particular, in order to improve the adhesion between the layers of a polarizing film, simply selecting a resin layer that has good compatibility with the polymer of the polymerizable liquid crystal compound will result in the compatibility of the dichroic dye contained in the polarizer with the resin layer. Since the solubility is also improved, thermal diffusion of the dichroic dye tends to be noticeable. In the present invention, since the first resin layer and the second resin layer are each composed of a cured product of a curable composition containing a (meth)acrylic compound, in an embodiment in which a crosslinked structure can be formed, in addition to adhesion, It can also have excellent heat resistance, and can effectively suppress deterioration of the polarizing performance of the polarizing film even when exposed to a high temperature environment for a long time. In this specification, heat resistance refers to a property that can suppress a decrease in polarization performance, such as a change in polarization degree or transmittance, even if exposed to a high-temperature environment for a long time. Improved indicates less deterioration or change in polarization performance.

In the polarizing film of the present invention, the polymerizable liquid crystal compound (hereinafter sometimes referred to as "polymerizable liquid crystal compound (A)") contained in the polarizer-forming composition is a liquid crystal having at least one (meth)acryloyl group. The liquid crystal compound is preferably a liquid crystal compound having two or more (meth)acryloyl groups from the viewpoint of improving the adhesiveness and heat resistance of the polarizing film. Moreover, the polymerizable liquid crystal compound (A) may contain a polymerizable group other than the (meth)acryloyl group. A polymerizable group refers to a group that can participate in a polymerization reaction by active radicals, acids, etc. generated from a polymerization initiator. Examples of the polymerizable group other than the (meth)acryloyl group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, oxiranyl group, and oxetanyl group. In the present invention, from the viewpoint of adhesiveness and heat resistance of the polarizing film, the polymerizable group of the polymerizable liquid crystal compound (A) is preferably composed of a (meth)acryloyl group, and is preferably composed of a (meth)acryloyloxy group. It is more preferable that the

In the present invention, the polymerizable liquid crystal compound (A) is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizer with a high degree of alignment order can be formed. The liquid crystal state exhibited by the polymerizable liquid crystal compound (A) is a smectic phase (smectic liquid crystal state), and from the viewpoint of realizing a higher degree of orientational order, a higher order smectic phase (higher order smectic liquid crystal state) is preferable. preferable. Here, the higher-order smectic phases include smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase, and smectic L phase. Among these, smectic B phase, smectic F phase, and smectic I phase are more preferable. The liquid crystal may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferable because it allows precise control of the film thickness. Further, the polymerizable liquid crystal compound (A) may be a monomer, but may also be an oligomer or a polymer in which a polymerizable group is polymerized.

The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a liquid crystal compound having at least one (meth)acryloyl group, and any known polymerizable liquid crystal compound can be used, but a compound exhibiting smectic liquid crystal properties may be used. preferable. Examples of such polymerizable liquid crystal compounds include a compound represented by the following formula (A1) (hereinafter sometimes referred to as "polymerizable liquid crystal compound (A1)").
U ¹ -V ¹ -W ¹ -(X ¹ -Y ¹ -) _n -X ² -W ² -V ² -U ² (A1)
[In formula (A1),
X ¹ and X ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group; The hydrogen atom contained in the group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group. Often, the carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. However, at least one of X ¹ and X ² is a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent.
Y ¹ is a single bond or a divalent linking group.
n is 1 to 3, and when n is 2 or more, a plurality of X ¹ 's may be the same or different. X ² may be the same as or different from any or all of the plurality of X ¹ s. Further, when n is 2 or more, the plurality of Y ¹ 's may be the same or different. From the viewpoint of liquid crystallinity, n is preferably 2 or more.
U ¹ represents a hydrogen atom or a (meth)acryloyloxy group.
U ² represents a (meth)acryloyloxy group.
W ¹ and W ² are each independently a single bond or a divalent linking group.
V ¹ and V ² each independently represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and -CH ₂ - constituting the alkanediyl group is -O-, It may be replaced with -CO-, -S- or NH-. ]

In the polymerizable liquid crystal compound (A1), X ¹ and X ² are preferably a 1,4-phenylene group which may have a substituent or a 1,4-phenylene group which may have a substituent, independently of each other. It is a good cyclohexane-1,4-diyl group, and at least one of X ¹ and X ² is a 1,4-phenylene group that may have a substituent or It is preferably a cyclohexane-1,4-diyl group, preferably a trans-cyclohexane-1,4-diyl group. The optional substituents of the 1,4-phenylene group which may have a substituent or the cyclohexane-1,4-diyl group which may have a substituent include a methyl group, an ethyl group, and alkyl groups having 1 to 4 carbon atoms such as butyl groups, cyano groups, and halogen atoms such as chlorine atoms and fluorine atoms. Preferably it is unsubstituted.

Further, the polymerizable liquid crystal compound (A1) has the formula (A1-1) in the formula (A1):
-(X ¹ -Y ¹ -) _n -X ² - (A1-1)
[In the formula, X ¹ , Y ¹ , X ² and n each have the same meaning as above. ]
The part shown by [hereinafter referred to as partial structure (A1-1)]. ] is preferably an asymmetric structure because it facilitates the development of smectic liquid crystallinity.
Examples of the polymerizable liquid crystal compound (A1) in which the partial structure (A1-1) is an asymmetric structure include a polymerizable liquid crystal compound (A1) in which n is 1 and one X ¹ and one X ² have different structures. ). Also, a compound in which n is 2, two Y ^1s have the same structure, two X ^1s have the same structure, and one X ² has a different structure from these two X ^1s . In the polymerizable liquid crystal compound (A1), of the two X ¹ , X ¹ bonded to W ¹ has a different structure from the other X ¹ and X ² , and the other X ¹ and X ² have the same structure. Also included is the polymerizable liquid crystal compound (A1). Furthermore, a compound in which n is 3, three Y ^1s have the same structure, and any one of the three X ^1s and one X ² has a structure different from all of the other three. and a liquid crystal compound (A1).

Y ¹ is -CH ₂ CH ₂ -, -CH ₂ O-, -CH ₂ CH ₂ O-, -COO-, -OCOO-, single bond, -N=N-, -CR ^a =CR ^b -, -C≡C-, -CR ^a =N- or CO-NR ^a - is preferred. R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. It is more preferable that Y ¹ is -CH ₂ CH ₂ -, -COO-, or a single bond, and when a plurality of Y ¹ exists, Y ¹ bonded to X ² is -CH ₂ CH ₂ - or CH ₂ O- is more preferred. When X ¹ and X ² all have the same structure, it is preferable that two or more Y ¹ exist with mutually different bonding methods. When a plurality of Y ¹ 's with mutually different bonding methods are present, an asymmetric structure is formed and smectic liquid crystallinity tends to occur easily.

U ² is a (meth)acryloyloxy group. U ¹ is a hydrogen atom or a (meth)acryloyloxy group, preferably a (meth)acryloyloxy group. From the viewpoint of improving interlayer adhesion and heat resistance of the polarizing film, it is preferable that both U ¹ and U ² are (meth)acryloyloxy groups. The (meth)acryloyloxy group may be in a polymerized state or in an unpolymerized state, but is preferably in an unpolymerized state.

Examples of the alkanediyl group represented by V ¹ and V ² include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, and a pentane-1,3-diyl group. 1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, decane-1,10-diyl group, tetradecane-1,14-diyl group and icosane-1,20-diyl group. V ¹ and V ² are preferably alkanediyl groups having 2 to 12 carbon atoms, more preferably alkanediyl groups having 6 to 12 carbon atoms.

Examples of the optional substituents of the alkanediyl group include a cyano group and a halogen atom, but the alkanediyl group is preferably unsubstituted and is an unsubstituted linear alkanediyl group. is more preferable.

W ¹ and W ² are preferably a single bond, -O-, -S-, -COO-, or OCOO-, and more preferably a single bond or O-, independently of each other.

The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a polymerizable liquid crystal compound having at least one (meth)acryloyl group, and any known polymerizable liquid crystal compound can be used, but it may exhibit smectic liquid crystallinity. Preferably, the structure that tends to exhibit smectic liquid crystallinity preferably has an asymmetric molecular structure in its molecular structure, and specifically has the following partial structures (A-a) to (A-i). More preferably, it is a polymerizable liquid crystal compound that exhibits smectic liquid crystallinity. It is more preferable to have a partial structure of (A-a), (Ab) or (A-c) from the viewpoint of easily exhibiting high-order smectic liquid crystallinity. Note that in (A-a) to (A-i) below, * represents a bond (single bond).

Specific examples of the polymerizable liquid crystal compound (A) include compounds represented by formulas (A-1) to (A-25). When the polymerizable liquid crystal compound (A) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably in the trans form.

Among these, formula (A-2), formula (A-3), formula (A-4), formula (A-5), formula (A-6), formula (A-7), formula (A- 8), at least one compound selected from the group consisting of compounds represented by formula (A-13), formula (A-14), formula (A-15), formula (A-16), and formula (A-17). Seeds are preferred. As the polymerizable liquid crystal compound (A), one type may be used alone, or two or more types may be used in combination.

The polymerizable liquid crystal compound (A) is manufactured by, for example, Lub et al., Recl. Trav. Chim. It can be produced by the known method described in Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

In the present invention, the composition for forming a polarizer may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (A), but from the viewpoint of obtaining a polarizer with a high degree of alignment order, The ratio of the polymerizable liquid crystal compound (A) to the total mass of all polymerizable liquid crystal compounds contained in the composition for use is preferably 51% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass. % or more.

Further, when the polarizer-forming composition contains two or more types of polymerizable liquid crystal compounds (A), at least one of them may be a polymerizable liquid crystal compound (A1), and all of them may be a polymerizable liquid crystal compound (A1). (A1) may also be used. By combining a plurality of polymerizable liquid crystal compounds, it may be possible to temporarily maintain liquid crystallinity even at temperatures below the liquid crystal-crystal phase transition temperature.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizer is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, based on the solid content of the composition for forming a polarizer. The content is more preferably 70 to 99% by mass. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. In addition, in this specification, solid content refers to the total amount of components excluding the solvent from the polarizer-forming composition.

In the present invention, a polarizer-forming composition that forms a polarizer contains a dichroic dye. Here, the dichroic dye refers to a dye that has a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction of the molecule. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the above properties, and may be a dye or a pigment. Further, two or more types of dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. Further, the dichroic dye may have polymerizability or liquid crystallinity.

The dichroic dye preferably has a maximum absorption wavelength (λ _MAX ) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes.

Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, with bisazo dyes and trisazo dyes being preferred, such as compounds represented by formula (I) (hereinafter referred to as "compounds"). (I).).
K ¹ (-N=N-K ² ) _p -N=N-K ³ (I)
[In formula (I), K ¹ and K ³ are each independently a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a naphthyl group which may have a substituent. Represents a good monovalent heterocyclic group. K ² is a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocycle which may have a substituent. represents a group. p represents an integer from 1 to 4. When p is an integer of 2 or more, a plurality of K ² may be the same or different from each other. The -N=N- bond may be replaced by a -C=C-, -COO-, -NHCO-, or -N=CH- bond within a range that exhibits absorption in the visible region. ]

Examples of the monovalent heterocyclic group include groups obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms from the above-mentioned heterocyclic compound.

As a substituent optionally possessed by the phenyl group, naphthyl group, and monovalent heterocyclic group in K ¹ and K ³ , and the p-phenylene group, naphthalene-1,4-diyl group, and divalent heterocyclic group in K ² is an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms having a polymerizable group, an alkenyl group having 1 to 4 carbon atoms; a methoxy group, an ethoxy group, a butoxy group having 1 to 20 carbon atoms; Alkoxy group; alkoxy group having 1 to 20 carbon atoms and having a polymerizable group; fluorinated alkyl group having 1 to 4 carbon atoms such as trifluoromethyl group; cyano group; nitro group; halogen atom; amino group, diethylamino group, pyrrolidino group Substituted or unsubstituted amino groups such as groups (substituted amino groups refer to amino groups having one or two alkyl groups having 1 to 6 carbon atoms, and one alkyl group having 1 to 6 carbon atoms having a polymerizable group) or an amino group having two amino groups, or an amino group in which two substituted alkyl groups bond to each other to form an alkanediyl group having 2 to 8 carbon atoms. An unsubstituted amino group is -NH _2. ) etc. In addition, examples of the polymerizable group include an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group.

［式（Ｉ－１）～（Ｉ－８）中、
Ｂ^１～Ｂ^３０は、互いに独立して、水素原子、炭素数１～６のアルキル基、炭素数１～６のアルケニル基、炭素数１～４のアルコキシ基、シアノ基、ニトロ基、置換又は無置換のアミノ基（置換アミノ基及び無置換アミノ基の定義は前記のとおり）、塩素原子又はトリフルオロメチル基を表わす。
ｎ１～ｎ４は、互いに独立に０～３の整数を表わす。
ｎ１が２以上である場合、複数のＢ^２は互いに同一でも異なっていてもよく、
ｎ２が２以上である場合、複数のＢ^６は互いに同一でも異なっていてもよく、
ｎ３が２以上である場合、複数のＢ^９は互いに同一でも異なっていてもよく、
ｎ４が２以上である場合、複数のＢ^１４は互いに同一でも異なっていてもよい。］ Among compound (I), compounds represented by any of the following formulas (I-1) to (I-6) are preferred.

[In formulas (I-1) to (I-8),
B ¹ to B ³⁰ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or It represents an unsubstituted amino group (the definitions of a substituted amino group and an unsubstituted amino group are as above), a chlorine atom, or a trifluoromethyl group.
n1 to n4 each independently represent an integer of 0 to 3.
When n1 is 2 or more, the plurality of ^B2s may be the same or different from each other,
When n2 is 2 or more, the plurality of ^B6s may be the same or different from each other,
When n3 is 2 or more, multiple ^B9s may be the same or different from each other,
When n4 is 2 or more, the plurality of ^B14s may be the same or different from each other. ]

［式（Ｉ－９）中、
Ｒ^１～Ｒ^８は、互いに独立して、水素原子、－Ｒ^ｘ、－ＮＨ_２、－ＮＨＲ^ｘ、－ＮＲ^ｘ _２、－ＳＲ^ｘ又はハロゲン原子を表わす。
Ｒ^ｘは、炭素数１～４のアルキル基又は炭素数６～１２のアリール基を表わす。］ The anthraquinone dye is preferably a compound represented by formula (I-9).

[In formula (I-9),
R ¹ to R ⁸ each independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（Ｉ－８）中、
Ｒ^９～Ｒ^１５は、互いに独立して、水素原子、－Ｒ^ｘ、－ＮＨ_２、－ＮＨＲ^ｘ、－ＮＲ^ｘ _２、－ＳＲ^ｘ又はハロゲン原子を表わす。
Ｒ^ｘは、炭素数１～４のアルキル基又は炭素数６～１２のアリール基を表わす。］ The oxazone dye is preferably a compound represented by formula (I-10).

[In formula (I-8),
R ⁹ to R ¹⁵ each independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

［式（Ｉ－１１）中、
Ｒ^１６～Ｒ^２３は、互いに独立して、水素原子、－Ｒ^ｘ、－ＮＨ_２、－ＮＨＲ^ｘ、－ＮＲ^ｘ _２、－ＳＲ^ｘ又はハロゲン原子を表わす。
Ｒ^ｘは、炭素数１～４のアルキル基又は炭素数６～１２のアリール基を表わす。］
式（Ｉ－９）、式（Ｉ－１０）及び式（Ｉ－１１）において、Ｒ^ｘの炭素数１～６のアルキル基としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基及びヘキシル基等が挙げられ、炭素数６～１２のアリール基としては、フェニル基、トルイル基、キシリル基及びナフチル基等が挙げられる。 The acridine dye is preferably a compound represented by formula (I-11).

[In formula (I-11),
R ¹⁶ to R ²³ each independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom.
R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]
In formula (I-9), formula (I-10) and formula (I-11), the alkyl group having 1 to 6 carbon atoms in R ^x includes methyl group, ethyl group, propyl group, butyl group, pentyl group. Examples of the aryl group having 6 to 12 carbon atoms include phenyl group, tolyl group, xylyl group, and naphthyl group.

［式（Ｉ－１２）中、
Ｄ^１及びＤ^２は、互いに独立に、式（Ｉ－１２ａ）～式（Ｉ－１２ｄ）のいずれかで表される基を表わす。

ｎ５は１～３の整数を表わす。］

［式（Ｉ－１３）中、
Ｄ^３及びＤ^４は、互いに独立に、式（Ｉ－１３ａ）～式（１－１３ｈ）のいずれかで表される基を表わす。

ｎ６は１～３の整数を表わす。］ The cyanine dye is preferably a compound represented by formula (I-12) or a compound represented by formula (I-13).

[In formula (I-12),
D ¹ and D ² each independently represent a group represented by any one of formulas (I-12a) to (I-12d).

n5 represents an integer from 1 to 3. ]

[In formula (I-13),
D ³ and D ⁴ each independently represent a group represented by any one of formulas (I-13a) to (1-13h).

n6 represents an integer from 1 to 3. ]

Among these dichroic dyes, azo dyes have high linearity and are suitable for producing polarizers with excellent polarization performance. Even if the diffusion occurs, the influence on the optical properties becomes large. In the present invention, also in such a polarizer, since the first resin layer and the second resin layer are each composed of a cured product of a curable composition containing a (meth)acrylic compound, in a preferred embodiment, a two-color polarizer is used. It is possible to effectively suppress the diffusion (especially thermal diffusion) of the polarizing dye, and effectively suppress the deterioration of polarization performance. Therefore, in one embodiment of the present invention, the dichroic dye contained in the polarizer-forming composition that forms the polarizer is preferably an azo dye.

In the present invention, the weight average molecular weight of the dichroic dye is usually 300 to 2,000, preferably 400 to 1,000. If the weight average molecular weight of the dichroic dye is below the above upper limit, the dichroic dye that exists in the polarizer in a state of being included in the polymerizable liquid crystal compound will be easy to move, and will be easily moved out of the polarizer under high temperature environment etc. It becomes easier to spread. Even in such a case, in the present invention, since the first resin layer and the second resin layer are each composed of a cured product of a curable composition containing a (meth)acrylic compound, in a preferred embodiment, dichroic Diffusion of the dye (especially thermal diffusion) can be effectively suppressed, and deterioration of polarization performance can be effectively suppressed.

In one embodiment of the present invention, the dichroic dye contained in the polarizer-forming composition that forms the polarizer is preferably hydrophobic. When the dichroic dye is hydrophobic, the compatibility between the dichroic dye and the polymerizable liquid crystal compound improves, the dichroic dye and the polymerizable liquid crystal compound form a uniform phase state, and the degree of orientational order is high. A polarizer having the following can be obtained. In the present invention, a hydrophobic dichroic dye refers to a dye having a solubility in 100 g of water at 25° C. of 1 g or less.

The content of the dichroic dye in the composition for forming a polarizer can be appropriately determined depending on the type of dichroic dye used, but is preferably 0.1 to 100 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound. The amount is 50 parts by weight, more preferably 0.1 to 20 parts by weight, and still more preferably 0.1 to 12 parts by weight. When the content of the dichroic dye is within the above range, it is difficult to disturb the orientation of the polymerizable liquid crystal compound, and a polarizer having a high degree of orientational order can be obtained.

In the present invention, a polarizer-forming composition for forming a polarizer may contain a polymerization initiator. The polymerization initiator is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound, and a photopolymerization initiator is preferable because it can initiate the polymerization reaction under lower temperature conditions. Specifically, photopolymerization initiators that can generate active radicals or acids by the action of light can be mentioned, and among them, photopolymerization initiators that can generate radicals by the action of light are preferred. Polymerization initiators can be used alone or in combination.

As the photopolymerization initiator, a known photopolymerization initiator can be used. For example, as a photopolymerization initiator that generates active radicals, a self-cleavage type photopolymerization initiator, a hydrogen abstraction type photopolymerization initiator, etc. There is.
As self-cleavable photopolymerization initiators, self-cleavable benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. Can be used. In addition, hydrogen abstracting type photopolymerization initiators include hydrogen abstracting benzophenone compounds, benzoin ether compounds, benzyl ketal compounds, dibenzosuberone compounds, anthraquinone compounds, xanthone compounds, thioxanthone compounds, and halogenoacetophenone compounds. compounds, dialkoxyacetophenone compounds, halogenobisimidazole compounds, halogenotriazine compounds, triazine compounds, etc. can be used.

As the photopolymerization initiator that generates acid, iodonium salts, sulfonium salts, etc. can be used.

Among these, reaction at low temperatures is preferred from the viewpoint of preventing dissolution of the dye, and self-cleavable photoinitiators are preferred from the viewpoint of reaction efficiency at low temperatures, particularly acetophenone compounds, hydroxyacetophenone compounds, and α-aminoacetophenone. and oxime ester compounds are preferred.

Specific examples of the photopolymerization initiator include the following.
Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether;
2-Hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy-2-methyl-1-[4-(2- Hydroxyacetophenones such as oligomers of hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenylketone and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one system compound;
α-Aminoacetophenones such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one, etc. system compound;
1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3 -yl]-, 1-(O-acetyloxime) and other oxime ester compounds;
Acyl phosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;
Benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone and 2,4, Benzophenone compounds such as 6-trimethylbenzophenone;
Dialkoxyacetophenone compounds such as diethoxyacetophenone;
2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3, 5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5 -Methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5- Triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine and 2,4-bis(trichloromethyl)-6- Triazine compounds such as [2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine. The photopolymerization initiator may be appropriately selected, for example, from the above-mentioned photopolymerization initiators in relation to the polymerizable liquid crystal compound contained in the polarizer-forming composition.

Alternatively, a commercially available photopolymerization initiator may be used. Commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, and 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (manufactured by IDM Resins B.V.); Sequal (registered trademark) BZ, Z, and BEE (manufactured by Seiko Kagaku Co., Ltd.); Kayacure (registered trademark) BP100, and UVI-6992 (manufactured by・Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka Arcles NCI-831, Adeka Arcles NCI-930 (manufactured by ADEKA Corporation); TAZ-A, and TAZ-PP (manufactured by Nihon Siberhegner Co., Ltd.); and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); and the like.

The content of the polymerization initiator in the polarizer-forming composition for forming a polarizer is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. parts, more preferably 2 to 8 parts by weight, particularly preferably 4 to 8 parts by weight. When the content of the polymerization initiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can be carried out without significantly disturbing the orientation of the polymerizable liquid crystal compound.

Furthermore, from the viewpoint of line contamination and handling during production, the polymerization rate of the polymerizable liquid crystal compound in the present invention is preferably 60% or more, more preferably 65% or more, and even more preferably 70% or more.

The polarizer-forming composition may further contain a photosensitizer. By using a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of photosensitizers include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene compounds such as anthracene and anthracene containing an alkoxy group (e.g., dibutoxyanthracene, etc.); Examples include phenothiazine and rubrene. The photosensitizers can be used alone or in combination of two or more.

When the polarizer-forming composition contains a photosensitizer, the content may be determined as appropriate depending on the type and amount of the polymerization initiator and polymerizable liquid crystal compound, but 100 parts by mass of the polymerizable liquid crystal compound The amount is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 10 parts by weight, and even more preferably 0.5 to 8 parts by weight.

Moreover, the composition for forming a polarizer may contain a leveling agent. The leveling agent has the function of adjusting the fluidity of the composition for forming a polarizer and making the coating film obtained by applying the composition for forming a polarizer more flat. Examples include agents. The leveling agent is preferably at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. Leveling agents can be used alone or in combination of two or more.

Examples of leveling agents containing polyacrylate compounds as a main component include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", and "BYK-358N". , "BYK-361N", "BYK-380", "BYK-381" and "BYK-392" (BYK Chemie).

Examples of leveling agents containing fluorine atom-containing compounds include "Megafac (registered trademark) R-08", "Megafac (registered trademark) R-30", "Megafac (registered trademark) R-90", "Megafac (registered trademark) F-410", “F-411”, “F-443”, “F-445”, “F-470”, “F-471”, “F-477”, “F-479”, “ "F-482" and "F-483" (DIC Corporation); "Surflon (registered trademark) S-381", "S-382", "S-383", "S-393", "SC-101", "SC-105", "KH-40" and "SA-100" (AGC Seimi Chemical Co., Ltd.); "E1830", "E5844" (Daikin Fine Chemical Research Institute Co., Ltd.) ; "F-TOP EF301", "F-TOP EF303", "F-TOP EF351" and "F-TOP EF352" (Mitsubishi Materials Electronic Chemicals Co., Ltd.).

When the polarizer-forming composition contains a leveling agent, the content thereof is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. . When the content of the leveling agent is within the above range, it is easy to horizontally align the polymerizable liquid crystal compound, and there is a tendency that unevenness is less likely to occur and a smoother polarizer can be obtained.

The composition for forming a polarizer may contain additives other than the photosensitizer and the leveling agent. Other additives include, for example, antioxidants, mold release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When the polarizer-forming composition contains other additives, the content of the other additives must be more than 0% and 20% by mass or less based on the solid content of the polarizer-forming composition. is preferable, and more preferably more than 0% and 10% by mass or less.

The composition for forming a polarizer can be produced by a conventionally known method for preparing a composition for forming a polarizer, and usually contains a polymerizable liquid crystal compound, a dichroic dye, and, if necessary, a polymerization initiator and the above. It can be prepared by mixing and stirring additives and the like. In addition, since compounds exhibiting smectic liquid crystallinity generally have high viscosity, a solvent may be added to the polarizer-forming composition in order to improve the coating properties of the polarizer-forming composition and facilitate the formation of the polarizer. The viscosity may be adjusted by

The solvent used in the polarizer-forming composition can be appropriately selected depending on the solubility of the polymerizable liquid crystal compound and dichroic dye used. Specifically, for example, alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether, ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, and γ-butyrolactone. , propylene glycol methyl ether acetate, ester solvents such as ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, toluene, etc. , aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents can be used alone or in combination of two or more. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and even more preferably 180 to 600 parts by mass, based on 100 parts by mass of the solid content of the polarizer-forming composition. Department.

In the polarizing film of the present invention, the polarizer preferably has a high degree of orientational order. A polarizer with a high degree of orientational order can obtain a Bragg peak derived from a higher-order structure such as a hexatic phase or a crystal phase in X-ray diffraction measurement. The Bragg peak means a peak derived from a planar periodic structure of molecular orientation. Therefore, it is preferable that the polarizer constituting the polarizing film of the present invention exhibits a Bragg peak in X-ray diffraction measurement. That is, in the polarizer constituting the polarizing film of the present invention, it is preferable that the polymerizable liquid crystal compound or its polymer be oriented so that the polarizer exhibits a Bragg peak in X-ray diffraction measurement. A "horizontal alignment" in which the molecules of the polymerizable liquid crystal compound are aligned in the absorption direction is more preferable. In the present invention, a polarizer having a molecular orientation plane periodic interval of 3.0 to 6.0 Å is preferable. A high degree of orientational order that exhibits a Bragg peak can be achieved by controlling the type of polymerizable liquid crystal compound used, the type and amount of the dichroic dye, the type and amount of the polymerization initiator, and the like.

In one embodiment of the present invention, the polarizer is formed by forming a coating film of a polarizer-forming composition on an alignment film, removing a solvent from the coating film, and causing a phase transition of a polymerizable liquid crystal compound to a liquid phase. It can be obtained by a method including raising the temperature to a temperature higher than that temperature and then lowering the temperature to cause a phase transition of the polymerizable liquid crystal compound to a smectic phase, and polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase. .

Methods for applying the polarizer-forming composition to alignment films include coating methods such as spin coating, extrusion, gravure coating, die coating, bar coating, and applicator methods, and printing such as flexography. Examples include known methods such as the method.

Next, a dry coating film is formed by removing the solvent by drying or the like under conditions in which the polymerizable liquid crystal compound contained in the coating film obtained from the polarizer-forming composition does not polymerize. Examples of the drying method include natural drying, ventilation drying, heating drying, and reduced pressure drying.

Furthermore, in order to cause a phase transition of the polymerizable liquid crystal compound to a liquid phase, the temperature is raised to a temperature above which the polymerizable liquid crystal compound undergoes a phase transition to a liquid phase, and then the temperature is lowered to transform the polymerizable liquid crystal compound into a smectic phase (smectic liquid crystal state). cause a phase transition. Such a phase transition may be performed after removing the solvent in the coating film, or may be performed simultaneously with the removal of the solvent.

By polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, a polarizer is formed as a cured layer of the polarizer-forming composition. As the polymerization method, a photopolymerization method is preferred. In photopolymerization, the light irradiated to the dry coating film depends on the type of polymerizable liquid crystal compound contained in the dry coating film (in particular, the type of polymerizable group possessed by the polymerizable liquid crystal compound), the type of polymerization initiator, and They are appropriately selected depending on their amounts and the like. Specific examples include one or more active energy rays and active electron rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays. Among these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use photopolymerization equipment that is widely used in the field. It is preferable to select the type of polymerizable liquid crystal compound and polymerization initiator contained in the composition for forming a polarizer. Moreover, during polymerization, the polymerization temperature can also be controlled by irradiating light while cooling the dried coating film with an appropriate cooling means. A patterned polarizer can also be obtained by performing masking or development during photopolymerization.

Examples of the light source of the active energy ray include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, and a wavelength range. Examples include an LED light source that emits light in the range of 380 to 440 nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/cm ² . The ultraviolet irradiation intensity is preferably in a wavelength range effective for activating the polymerization initiator. The light irradiation time is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiated once or multiple times with such ultraviolet irradiation intensity, the cumulative amount of light is 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , more preferably 100 to 1,000 mJ/cm It is ² .

By performing photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining a liquid crystal state of a smectic phase, preferably a higher-order smectic phase, and a polarizer is formed. A polarizer obtained by polymerizing a polymerizable liquid crystal compound while maintaining a smectic phase liquid crystal state is a polarizer obtained by polymerizing a polymerizable liquid crystal compound while maintaining a smectic phase liquid crystal state. It has the advantage of high polarization performance compared to other polarizers. Furthermore, it has the advantage of being superior in strength compared to those coated with only dichroic dyes or lyotropic liquid crystals.

The thickness of the polarizer can be appropriately selected depending on the display device to which it is applied, and is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and even more preferably 0.5 to 3 μm. be. If the film thickness of the polarizer is at least the above lower limit, it will be easier to prevent the necessary light absorption from being obtained, and if it is below the above upper limit, alignment defects will occur due to a decrease in the alignment regularity of the alignment film. easy to suppress. Note that the polarizer, polarizing plate, alignment film, first resin layer, and second resin layer can be measured using a laser microscope or a film thickness meter, respectively.

<Orientation film>
The alignment film included in the polarizing film of the present invention is formed on the surface of the polarizer opposite to the first resin layer. The alignment film has an alignment regulating force that causes the polymerizable liquid crystal compound to align the liquid crystal in a desired direction. The alignment film is preferably one that has a solvent resistance that does not dissolve when the composition for forming a polarizing film is applied, etc., and also has heat resistance during heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. In the present invention, the alignment film is a cured product of a composition for forming an alignment film containing a (meth)acrylic compound, and has excellent adhesion at the interface with the polarizer and the interface with the second resin layer. From the viewpoint of improving adhesion and heat resistance, the alignment film in the present invention is preferably a photo-alignment film formed by curing the composition for forming an alignment film with polarized light (preferably polarized UV).

The (meth)acrylic compound refers to a compound having at least one (meth)acryloyl group, and the (meth)acrylic compound may be a monomer, oligomer, or polymer. In the case of an oligomer or polymer, the double bond of the (meth)acryloyl group may be polymerized. The (meth)acrylic compound contained in the composition for forming a photo-alignment film preferably has a photoreactive group in addition to the (meth)acryloyl group.

The photoreactive group refers to a group that produces liquid crystal alignment ability when irradiated with light. Specifically, groups that are involved in photoreactions that are the origin of liquid crystal alignment ability, such as orientation induction of molecules caused by light irradiation, or isomerization reactions, dimerization reactions, photocrosslinking reactions, or photodecomposition reactions, can be mentioned. Among these, groups that participate in a dimerization reaction or a photocrosslinking reaction are preferable because they have excellent orientation. The photoreactive group is preferably a group having an unsaturated bond, especially a double bond, such as a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), or a nitrogen-nitrogen double bond. Particularly preferred is a group having at least one selected from the group consisting of a double bond (N=N bond) and a carbon-oxygen double bond (C=O bond).

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C=N bond include groups having structures such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N=N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, or a halogenated alkyl group.

Among these, photoreactive groups that participate in photodimerization reactions are preferred, since the amount of polarized light irradiation required for photoalignment is relatively small, and it is easy to obtain a photoalignment film with excellent thermal stability and stability over time. Cinnamoyl and chalcone groups are preferred. The (meth)acrylic oligomer or polymer contained in the composition for forming a photo-alignment film is particularly preferably one having a cinnamoyl group such that the end of the oligomer or polymer side chain has a cinnamic acid structure.

In one embodiment of the present invention, the photo-alignment film is formed by applying a composition for forming a photo-alignment film containing a (meth)acrylic compound and a solvent onto the second resin layer, and irradiating the composition with polarized light (preferably polarized UV). You can get it by doing. Examples of the solvent contained in the composition for forming a photo-alignment film include those similar to the solvents exemplified above as solvents that can be used when forming a polarizer, and may be used as appropriate depending on the solubility of the (meth)acrylic compound. You can choose.

The content of the (meth)acrylic compound in the composition for forming a photo-alignment film can be adjusted as appropriate depending on the type of (meth)acrylic compound and the desired thickness of the photo-alignment film, but the weight of the composition for forming a photo-alignment film The amount is preferably at least 0.2% by weight, more preferably from 0.3 to 10% by weight. The composition for forming a photo-alignment film may contain a polymeric material such as polyvinyl alcohol or polyimide, and a photosensitizer as long as the properties of the photo-alignment film are not significantly impaired.

The method of applying the composition for forming a photo-alignment film onto the second resin layer and the method of removing the solvent from the applied composition for forming a photo-alignment film include applying the composition for forming a polarizer onto the alignment film. Examples of the method for removing the solvent and the method for removing the solvent include the methods exemplified above.

Polarized light irradiation can be carried out either by directly irradiating polarized UV onto the photo-alignment film forming composition coated on the second resin layer from which the solvent has been removed, or by irradiating polarized light from the second resin layer side. A format in which the light is transmitted and irradiated may also be used. Moreover, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which the photoreactive group and/or (meth)acryloyl group of the (meth)acrylic compound can absorb light energy. Specifically, UV (ultraviolet light) having a wavelength in the range of 250 to 400 nm is particularly preferred. Examples of light sources used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF. preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they emit a high intensity of ultraviolet light with a wavelength of 313 nm. Polarized UV can be irradiated by passing the light from the light source through a suitable polarizer. As such a polarizer, a polarizing filter, a polarizing prism such as Glan-Thompson or Glan-Taylor, or a wire grid type polarizer can be used.

Note that by performing masking when performing rubbing or polarized light irradiation, it is also possible to form a plurality of regions (patterns) in which the directions of liquid crystal alignment are different.

The thickness of the alignment film is preferably 10 to 5000 nm, more preferably 10 to 1000 nm, and still more preferably 30 to 300 nm. When the thickness of the alignment film is within the above range, it is possible to exhibit good adhesion at the interface with the polarizer or the interface with the second resin layer, and to exhibit alignment regularity, so that the polarizer can be bonded to the polarizer with high alignment order. can be formed.

<First resin layer and second resin layer>
The first resin layer included in the polarizing film of the present invention is a cured product of a first curable composition containing a (meth)acrylic compound, and is formed on the surface of the polarizer opposite to the alignment film side. . In the present invention, since both the first resin layer and the polarizer are formed from a compound having a (meth)acryloyl group, the compatibility between the layers is high, and the (meth)acrylic compound contained in the first curable composition Since the polarizer and the polymerizable liquid crystal compound having a (meth)acryloyl group contained in the polarizer can form a crosslinked structure, excellent adhesion at the layer interface can be achieved.
The second resin layer included in the polarizing film of the present invention is a cured product of a second curable composition containing a (meth)acrylic compound, and is formed on the surface of the alignment film opposite to the polarizer side. . In the present invention, since both the second resin layer and the alignment film are formed from a compound having a (meth)acryloyl group, the compatibility between the layers is high, and the (meth)acrylic compound contained in the second curable composition Since this and the (meth)acrylic compound contained in the alignment film can form a crosslinked structure, excellent adhesion at the layer interface can be achieved.

The (meth)acrylic compound contained in the first curable composition and the second curable composition is a compound having at least one (meth)acryloyl group, and may be a monomer, oligomer, or polymer. Examples of (meth)acrylic compounds include (meth)acrylate compounds such as monofunctional (meth)acrylate compounds and polyfunctional (meth)acrylate compounds; urethane (meth)acrylate compounds such as polyfunctional urethane (meth)acrylate compounds; Examples include epoxy (meth)acrylate compounds such as polyfunctional epoxy (meth)acrylate compounds; carboxyl group-modified epoxy (meth)acrylate compounds, polyester (meth)acrylate compounds, and the like. These can be used alone or in combination. Among these, polyfunctional (meth)acrylate compounds or urethane (meth)acrylate compounds are preferred from the viewpoint of easily improving the adhesion, heat resistance, and flexibility of the polarizing film. ) Acrylate is more preferably used in combination. The first curable composition (first resin layer) and the second curable composition (second resin layer) may have the same composition or different compositions, but have excellent adhesion, heat resistance, and flexibility. From the viewpoint of easily improving properties, it is preferable that they have the same composition. In addition, in this specification, flexibility means the characteristic which can suppress generation|occurrence|production of a crack etc. when a polarizing film is bent.

In one embodiment of the present invention, at least one of the first curable composition and the second curable composition contains a polyfunctional (meth)acrylate compound as the (meth)acrylic compound. This aspect is advantageous from the viewpoints of adhesiveness, heat resistance, and flexibility of the polarizing film.

A polyfunctional (meth)acrylate compound means a compound having two or more (meth)acryloyloxy groups in the molecule, and examples include a bifunctional (meth)acrylate compound having two (meth)acryloyloxy groups in the molecule. Examples include meth)acrylate monomers and trifunctional or higher-functional (meth)acrylate monomers having three or more (meth)acryloyloxy groups in the molecule. In addition, in this specification, the term "(meth)acrylate" means "acrylate" or "methacrylate", and the term "(meth)acryloyl" similarly means "acryloyl" or "methacryloyl".

As the polyfunctional (meth)acrylate compound, one type or two or more types of polyfunctional (meth)acrylate compounds may be included. Furthermore, when two or more types of polyfunctional (meth)acrylate compounds are included, the number of (meth)acryloyloxy groups may be the same or different between the respective polyfunctional (meth)acrylate compounds.

Examples of difunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. (meth)acrylate, alkylene glycol di(meth)acrylate such as 1,9-nonanediol di(meth)acrylate and neopentyl glycol di(meth)acrylate; diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate , dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polytetramethylene glycol di(meth)acrylate. Di(meth)acrylate; di(meth)acrylate of halogen-substituted alkylene glycol such as tetrafluoroethylene glycol di(meth)acrylate; trimethylolpropane di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, pentaerythritol di( Di(meth)acrylates of aliphatic polyols such as meth)acrylate; hydrogenated dicyclopentadiene or tricyclodecane di(meth)acrylate such as hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate; Di(meth)acrylate of alkanol; Di(meth)acrylate of dioxane glycol or dioxane dialkanol such as 1,3-dioxane-2,5-diyl di(meth)acrylate [also known as dioxane glycol di(meth)acrylate]; Bisphenol Di(meth)acrylate of alkylene oxide adducts of bisphenol A or bisphenol F such as A ethylene oxide adduct diacrylate, bisphenol F ethylene oxide adduct diacrylate; acrylic acid adduct of bisphenol A diglycidyl ether, bisphenol F Epoxy di(meth)acrylate of bisphenol A or bisphenol F such as acrylic acid adduct of diglycidyl ether; silicone di(meth)acrylate; di(meth)acrylate of hydroxypivalic acid neopentyl glycol ester; 2,2-bis[4 -(meth)acryloyloxyethoxyethoxyphenyl]propane; 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane; 2-(2-hydroxy-1,1-dimethylethyl)-5-ethyl- 5-hydroxymethyl-1,3-dioxane] di(meth)acrylate; tris(hydroxyethyl)isocyanurate di(meth)acrylate, and the like.

Trifunctional (meth)acrylate monomers are monomers that have three (meth)acryloyloxy groups in the molecule, and examples thereof include glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and ditrimethylol. Propane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, reaction product of pentaerythritol tri(meth)acrylate and acid anhydride, caprolactone-modified trimethylolpropane tri(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate , ethylene oxide modified trimethylolpropane tri(meth)acrylate, ethylene oxide modified pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, propylene oxide modified pentaerythritol tri(meth)acrylate, isocyanurate tri(meth)acrylate (meth)acrylate, reaction product of caprolactone-modified pentaerythritol tri(meth)acrylate and acid anhydride, reaction product of ethylene oxide-modified pentaerythritol tri(meth)acrylate and acid anhydride, propylene oxide-modified pentaerythritol tri(meth)acrylate and acid anhydride, ) Reaction products of acrylate and acid anhydride, etc.

Tetrafunctional (meth)acrylate monomers are monomers having four (meth)acryloyloxy groups in the molecule; examples thereof include ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, and ditrimethylolpropane tetra(meth)acrylate. Pentaerythritol tetra(meth)acrylate, tripentaerythritol tetra(meth)acrylate, caprolactone modified pentaerythritol tetra(meth)acrylate, caprolactone modified tripentaerythritol tetra(meth)acrylate, ethylene oxide modified pentaerythritol tetra(meth)acrylate, ethylene Examples include oxide-modified tripentaerythritol tetra(meth)acrylate, propylene oxide-modified pentaerythritol tetra(meth)acrylate, and propylene oxide-modified tripentaerythritol tetra(meth)acrylate.

Examples of pentafunctional (meth)acrylate monomers include dipentaerythritol penta(meth)acrylate, tripentaerythritol penta(meth)acrylate, reaction product of dipentaerythritol penta(meth)acrylate and acid anhydride, caprolactone-modified dipenta Erythritol penta(meth)acrylate, caprolactone modified tripentaerythritol penta(meth)acrylate, ethylene oxide modified dipentaerythritol penta(meth)acrylate, ethylene oxide modified tripentaerythritol penta(meth)acrylate, propylene oxide modified dipentaerythritol penta(meth)acrylate meth)acrylate, propylene oxide-modified tripentaerythritol penta(meth)acrylate, reaction product of caprolactone-modified dipentaerythritol penta(meth)acrylate and acid anhydride, ethylene oxide-modified dipentaerythritol penta(meth)acrylate and acid anhydride and a reaction product of propylene oxide-modified dipentaerythritol penta(meth)acrylate and an acid anhydride.

Examples of hexafunctional (meth)acrylate monomers include dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and caprolactone-modified tripentaerythritol hexa(meth)acrylate. , ethylene oxide modified dipentaerythritol hexa(meth)acrylate, ethylene oxide modified tripentaerythritol hexa(meth)acrylate, propylene oxide modified dipentaerythritol hexa(meth)acrylate, propylene oxide modified tripentaerythritol hexa(meth)acrylate, etc. Can be mentioned.

Examples of the heptafunctional (meth)acrylate monomer include tripentaerythritol hepta(meth)acrylate, a reaction product of tripentaerythritol hepta(meth)acrylate and an acid anhydride, caprolactone-modified tripentaerythritol hepta(meth)acrylate, and caprolactone-modified tripentaerythritol hepta(meth)acrylate. Reaction product of tripentaerythritol hepta(meth)acrylate and acid anhydride, ethylene oxide modified tripentaerythritol hepta(meth)acrylate, reaction product of ethylene oxide modified tripentaerythritol hepta(meth)acrylate and acid anhydride, propylene Examples include oxide-modified tripentaerythritol hepta(meth)acrylate, a reaction product of propylene oxide-modified tripentaerythritol hepta(meth)acrylate and an acid anhydride, and the like.

The 8-functional (meth)acrylate monomer is a monomer having 8 (meth)acryloyloxy groups in the molecule, and examples include tripentaerythritol octa(meth)acrylate, caprolactone-modified tripentaerythritol octa(meth) Acrylate, ethylene oxide-modified tripentaerythritol octa(meth)acrylate, propylene oxide-modified tripentaerythritol octa(meth)acrylate, and the like. These polyfunctional (meth)acrylate compounds can be used alone or in combination of two or more.

The number of (meth)acryloyl groups in the polyfunctional (meth)acrylate compound is preferably 6 or more, more preferably 7 or more, and even more preferably 8 or more. When the number of (meth)acryloyl groups in the polyfunctional (meth)acrylate compound is at least the above lower limit, the crosslinking density of the first resin layer or the second resin layer is increased, and the heat resistance of the polarizing film is more easily improved. . Further, the upper limit of the number of (meth)acryloyl groups is usually 20 or less.

By controlling the molecular weight between crosslinking points and the number of crosslinking points of the polyfunctional (meth)acrylate compound, the crosslinking density of the first resin layer or the second resin layer can be adjusted. More specifically, the smaller the molecular weight between crosslinking points, the higher the crosslinking density, and the larger the number of crosslinking points, the denser the crosslinking density, which can improve the heat resistance of the polarizing film.

In one embodiment of the present invention, from the viewpoint of controlling the crosslinking density and improving heat resistance, the polyfunctional (meth)acrylate compound has a branched structure, and the branch closest to the (meth)acryloyl group in the branched structure The number of atoms in the chain (sometimes referred to as a connecting chain) connecting the point and the (meth)acryloyl group is preferably 3 or less, more preferably 2 or less. When the number of atoms is below the above upper limit, the crosslinking density of the first resin layer or the second resin layer becomes large, and the heat resistance of the polarizing film tends to be improved. Here, if there are multiple linked chains, it is sufficient that at least one of the linked chains satisfies the above range of the number of atoms, and from the viewpoint of improving heat resistance, all the linked chains should satisfy the range of the number of atoms mentioned above. is preferred.

Among the polyfunctional (meth)acrylate compounds, dipentaerythritol hexa(meth)acrylate and tripentaerythritol octa(meth)acrylate are preferred from the viewpoint of heat resistance of the polarizing film.

In the first curable composition or the second curable composition, the content of the polyfunctional (meth)acrylate compound is preferably 50 parts by mass or more, more preferably is 60 parts by mass or more, more preferably 70 parts by mass or more, preferably 100 parts by mass or less, more preferably 95 parts by mass or less, even more preferably 90 parts by mass or less. When the content of the polyfunctional (meth)acrylate compound is within the above range, it is easy to improve the interlayer adhesion, heat resistance, and flexibility of the polarizing film. In addition, in this specification, the solid content of a curable composition means the total amount of components excluding a solvent from a curable composition, when a solvent is contained in a curable composition.

In one embodiment of the present invention, at least one of the first curable composition and the second curable composition preferably contains a urethane (meth)acrylate compound as the (meth)acrylic compound. This aspect is advantageous from the viewpoints of adhesiveness, heat resistance, and flexibility of the polarizing film.

Urethane (meth)acrylate compound generally means a reaction product of an isocyanate compound, a polyol compound, and a (meth)acrylate compound, and is a polyfunctional urethane (meth)acrylate having two or more (meth)acryloyloxy groups in the molecule. Preferably, it is a compound. Since a polyfunctional urethane (meth)acrylate compound can form a crosslinked structure, it is advantageous from the viewpoint of heat resistance of a polarizing film and can impart appropriate toughness. Therefore, the flexibility of the polarizing film may be increased and the resistance to deformation due to bending or the like may be improved.

From the viewpoint of heat resistance, the polyfunctional urethane (meth)acrylate compound preferably has a functional group number of 3 or less, and more preferably a functional group number of 2. Further, from the viewpoint of achieving both heat resistance and flexibility, the number of functional groups is preferably 2 to 5.

The weight average molecular weight (Mw) of the urethane (meth)acrylate compound is preferably 300 or more, more preferably 400 or more, and preferably 10,000 or less, more preferably 7,000 or less, and even more preferably 7,000 or less, in terms of polystyrene. It is 5,000 or less, particularly preferably 3,000 or less. When the Mw of the urethane (meth)acrylate compound is within the above range, adhesion and heat resistance are likely to be improved. Note that the weight average molecular weight (Mw) can be measured, for example, by gel permeation chromatography (GPC).

The urethane (meth)acrylate compound preferably has a number of (meth)acryloyl groups per unit molecular weight of 15×10 ⁻⁴ or more, more preferably 20×10 ⁻⁴ or more, and 30×10 ⁻⁴ or more. It is more preferable that it be at least 40×10 ⁻⁴ , particularly preferably at least 40×10 −4 . When the number of (meth)acryloyl groups per unit molecular weight is at least the above lower limit, the heat resistance and adhesiveness of the polarizing film can be more easily improved. Further, the upper limit of the number of (meth)acryloyl groups per unit molecular weight is usually 20 or less. The number of (meth)acryloyl groups per unit molecular weight can be calculated by the formula: number of (meth)acryloyl groups of urethane (meth)acrylate compound/weight average molecular weight (Mw).

When the first curable composition or the second curable composition contains a urethane (meth)acrylate compound, the content of the urethane (meth)acrylate compound is preferably based on 100 parts by mass of the solid content of the curable composition. is 10 parts by mass or more, more preferably 30 parts by mass or more, and preferably 100 parts by mass or less. When the content of the urethane (meth)acrylate compound is within the above range, the adhesiveness, heat resistance, and flexibility of the polarizing film can be easily improved.

When the first curable composition or the second curable composition contains a polyfunctional (meth)acrylate compound and a urethane (meth)acrylate compound, the polyfunctional (meth)acrylate compound and the urethane (meth)acrylate compound, Preferably, the ratio (polyfunctional (meth)acrylate compound:urethane (meth)acrylate compound, mass ratio) is 95:5 to 50:50, more preferably 90:10 to 70:30. By including the polyfunctional (meth)acrylate compound and the urethane (meth)acrylate compound in the above blending ratio, the adhesiveness, heat resistance, and flexibility of the polarizing film can be easily improved.

The first curable composition or the second curable composition may contain a monofunctional (meth)acrylate compound as necessary. The monofunctional (meth)acrylate compound may be a monomer, oligomer, or polymer, and among these, monofunctional (meth)acrylate monomers can be preferably used. Examples of monofunctional (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate ) acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, pentaerythritol mono(meth)acrylate, ethyl carbitol (meth)acrylate, 2-phenoxyethyl (meth)acrylate, Phenoxypolyethylene glycol (meth)acrylate, 2-(N,N-dimethylamino)ethyl (meth)acrylate, 2-carboxyethyl (meth)acrylate, 1-[2-(meth)acryloyloxyethyl]phthalic acid, 1- [2-(meth)acryloyloxyethyl]hexahydrophthalic acid, 1-[2-(meth)acryloyloxyethyl]succinic acid and 4-[2-(meth)acryloyloxyethyl] trimellitic acid, tetrahydrofurfuryl (meth) ) acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate acid, and the like. Monofunctional (meth)acrylate monomers can be used alone or in combination of two or more.

When the first curable composition or the second curable composition contains a monofunctional (meth)acrylate compound, the content of the monofunctional (meth)acrylate compound is based on 100 parts by mass of the solid content of the curable composition. , preferably 0 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less. When the content of the monofunctional (meth)acrylate compound is within the above range, the coating properties of the curable composition are improved from the viewpoint of adjusting the viscosity of the curable composition.

At least one of the first curable composition and the second curable composition preferably contains a radical polymerization initiator from the viewpoint of improving curability; More preferably, both contain a radical polymerization initiator. The radical polymerization initiator is not particularly limited as long as it can initiate curing of the curable compound by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams. Specific examples thereof include acetophenone, 3-Methylacetophenone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane Acetophenone initiators such as -1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone initiators such as benzophenone, 4-chlorobenzophenone and 4,4'-diaminobenzophenone; 2 , 2-dimethoxy-1,2-diphenylethan-1-one, alkylphenone initiators such as 1-hydroxy-cyclohexyl-phenyl-ketone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; 4- Thioxanthone initiators such as isopropylthioxanthone; acylphosphine oxide initiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; others include xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone, and the like. These radical polymerization initiators can be used alone or in combination.

When the first curable composition or the second curable composition contains a radical polymerization initiator, the content of the radical polymerization initiator is preferably 1 to 10 parts by mass based on 100 parts by mass of solid content of the curable compound. parts, more preferably 2 to 8 parts by weight. When the content of the radical polymerization initiator is equal to or higher than the above lower limit, polymerization initiation ability is sufficiently expressed and curability is improved. On the other hand, when the content of the polymerization initiator is below the above upper limit, the radical polymerization initiator becomes difficult to remain, making it easier to suppress a decrease in visible light transmittance.

The first curable composition or the second curable composition may optionally contain other additives other than the radical polymerization initiator, such as ultraviolet absorbers, antistatic agents, stabilizers, antioxidants, and colorants. , a surface conditioner, and the like. Other additives can be used alone or in combination. The content of other additives is preferably about 0.1 to 20% by mass based on the mass of the solid content of the curable composition.

The first curable composition or the second curable composition can be prepared by mixing and stirring the (meth)acrylic compound and, if necessary, additives and the like. Furthermore, in order to improve the applicability, the viscosity may be adjusted by adding a solvent to the first curable composition or the second curable composition.

The solvent may be any solvent as long as it can dissolve the components constituting the first curable composition or the second curable composition, such as aliphatic hydrocarbons such as hexane and octane; aromatic hydrocarbons such as toluene and xylene. Hydrocarbons; alcohols such as ethanol, 1-propanol, isopropanol, and 1-butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate, butyl acetate, and isobutyl acetate; ethylene glycol monomethyl ether, ethylene glycol mono Glycol ethers such as ethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; and esterified glycol ethers such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate may be used. Can be done. These solvents can be used alone or in combination. The type and content of the solvent are appropriately selected depending on the type, content, shape, coating method, thickness of the resin layer, etc. of the components contained in the first curable composition or the second curable composition. For example, the content of the solvent is preferably 3 to 1000 parts by weight, more preferably 5 to 100 parts by weight, and even more preferably 7 to 50 parts by weight, based on 100 parts by weight of the solid content of the curable composition.

In one embodiment of the present invention, the first resin layer is obtained by applying a first curable composition onto a polarizer or a release film and curing the composition. The second resin layer is obtained by applying the second curable composition onto the base material, release film, or alignment film and curing the composition.

Examples of the coating method of the first curable composition or the second curable composition include the coating methods exemplified in the section of <Polarizer>. Further, the curing of the curable composition is preferably carried out by irradiating active energy rays to polymerize a polymerizable component such as a (meth)acrylic compound contained in the composition. The active energy ray is appropriately selected depending on the type of polymerizable component such as a (meth)acrylic compound, the type of radical polymerization initiator, the amount thereof, and the like. Specific examples include one or more active energy rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays. Among these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use photopolymerization devices that are widely used in this field. Examples of the active energy ray light source include the light sources listed in the <Polarizer> section. For the ultraviolet irradiation intensity, irradiation time, and cumulative light amount, the ranges of the ultraviolet irradiation intensity, irradiation time, and cumulative light amount illustrated in the <Polarizer> section may be appropriately used.

The thickness of the first resin layer and the second resin layer is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm, and still more preferably 0.3 to 3 μm. When the thickness of the first resin layer or the second resin layer is within the above range, the adhesion between the first resin layer and the polarizer and the adhesion between the second resin layer and the alignment film can be easily improved. Moreover, it is easy to effectively suppress the diffusion of dichroic dyes contained in the polarizer, and it is easy to improve heat resistance.

<Polarizing film>
As described above, the polarizing film of the present invention has excellent adhesion between each layer. Furthermore, since the polarizing film also has excellent heat resistance, it is possible to effectively suppress the diffusion of the dichroic dye contained in the polarizer even in a high-temperature environment, thereby suppressing the deterioration of polarizing performance. Furthermore, in a preferred embodiment, excellent flexibility can be exhibited in addition to adhesion and heat resistance. Therefore, the polarizing film can be suitably used in display devices such as organic EL display devices and touch panel display devices.

The method for producing a polarizing film of the present invention is not particularly limited as long as the first resin layer, polarizer, alignment film, and second resin layer can be laminated in this order. An alignment film is formed on top, a polarizer is formed on the alignment film to obtain a laminate in which the second resin layer, the alignment film, and the polarizer are laminated in this order, and on the polarizer surface of the laminate, Examples include a method including a step of applying or overlapping a first curable composition and curing the first curable composition.

In a preferred embodiment of the present invention, the polarizing film of the present invention includes a laminate in which a second resin layer, an alignment film, and a polarizer are laminated on a release film. The release film, the second resin layer, the alignment film, the polarizer, and the first resin are cured by applying active energy rays from the first curable composition side and curing the first curable composition. It is produced by a method including the steps of obtaining a laminate having layers in this order and peeling off a release film from the laminate.

In a preferred embodiment of the present invention, the polarizing film of the present invention is a laminate in which a first curable composition formed on a release film, a second resin layer, an alignment film, and a polarizer are laminated in this order. The mold release film, the first resin layer, the polarizer, the alignment film, the second It is manufactured by a method including the steps of obtaining a laminate in which resin layers are laminated in this order and peeling a release film from the laminate.

In the polarizing film of the present invention, the first resin layer, the polarizer, the alignment film, and the second resin layer may be laminated in this order, and as long as the effects of the present invention are not impaired, the polarizer side of the first resin layer A functional layer may be included on the surface opposite to the second resin layer, on the surface opposite to the alignment film side of the second resin layer, or between each layer. Examples of the functional layer include an ultraviolet absorbing layer, a hard coat layer, a primer layer, a gas barrier layer, a hue adjusting layer, a refractive index adjusting layer, an antireflection layer, an antistatic layer, an adhesive layer, and an adhesive layer. These functional layers can be used alone or in combination of two or more.

[Polarizer]
The polarizing film of the present invention may be combined with a retardation film to form a polarizing plate. That is, the polarizing plate in the present invention includes the polarizing film and a retardation film. The retardation film may be laminated, for example, on the surface of the first resin layer or the second resin layer of the polarizing film via an adhesive layer or a pressure-sensitive adhesive layer. It is preferable to laminate so that the slow axis (optical axis) of the retardation film and the absorption axis of the polarizing film (polarizer) are substantially at 45°. By laminating the slow axis (optical axis) of the retardation film and the absorption axis of the polarizing film (polarizer) so that the angle is substantially 45°, the function as an elliptically polarizing plate can be obtained. Note that substantially 45° is usually in the range of 45±5°.

In the polarizing plate, the retardation film has the following formula (X):
100≦Re(550)≦180 (X)
[In the formula, Re (550) represents the in-plane retardation value at a wavelength of 550 nm]
It is preferable to satisfy the following. When the retardation film has an in-plane retardation value represented by (X) above, it functions as a so-called λ/4 plate. The formula (X) preferably satisfies 100 nm≦Re(550)≦180 nm, more preferably 120 nm≦Re(550)≦160 nm.

Furthermore, the retardation film has the following formula (Y):
Re(450)/Re(550) < 1 (Y)
[In the formula, Re (450) and Re (550) represent in-plane retardation values at wavelengths of 450 nm and 550 nm, respectively.]
It is preferable to satisfy the following. A retardation film that satisfies the above formula (Y) has so-called reverse wavelength dispersion and exhibits excellent polarization performance. The value of Re(450)/Re(550) is preferably 0.93 or less, more preferably 0.88 or less, even more preferably 0.86 or less, preferably 0.80 or more, more preferably 0. 82 or higher.

The retardation film may be a stretched film that provides a retardation by stretching a polymer, but from the viewpoint of making the polarizing plate thinner, a polymerizable liquid crystal composition containing a polymer of a polymerizable liquid crystal compound ( Hereinafter, it is preferably composed of a polymerizable liquid crystal composition (also referred to as (B)). In the retardation film, the polymerizable liquid crystal compound is usually polymerized in an oriented state. The polymerizable liquid crystal compound that forms the retardation film (hereinafter also referred to as "polymerizable liquid crystal compound (B)") means a liquid crystal compound that has a polymerizable functional group, particularly a photopolymerizable functional group. The photopolymerizable functional group refers to a group that can participate in a polymerization reaction by active radicals, acids, etc. generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, and the like. Among these, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The liquid crystal property may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the phase order structure may be a nematic liquid crystal or a smectic liquid crystal. As the polymerizable liquid crystal compound, only one type may be used, or two or more types may be used in combination.

Examples of the polymerizable liquid crystal compound (B) include compounds that satisfy all of the following (a) to (e) from the viewpoint of ease of film formation and imparting the retardation property represented by the above formula (Y). .

(a) A compound having thermotropic liquid crystallinity;
(a) The polymerizable liquid crystal compound has π electrons in the long axis direction (a).
(c) It has π electrons in the direction [intersecting direction (b)] that intersects with the major axis direction (a).
(d) A polymerizable liquid crystal compound defined by the following formula (i) where the total of π electrons existing in the major axis direction (a) is N (πa) and the total molecular weight present in the major axis direction is N (Aa) π electron density in the long axis direction (a):
D(πa)=N(πa)/N(Aa) (i)
and a polymerizable liquid crystal compound defined by the following formula (ii) where the total of π electrons existing in the intersecting direction (b) is N (πb), and the total molecular weight existing in the intersecting direction (b) is N (Ab) π electron density in the crossing direction (b):
D(πb)=N(πb)/N(Ab) (ii)
Toga,
0≦[D(πa)/D(πb)]≦1
[That is, the π electron density in the cross direction (b) is larger than the π electron density in the major axis direction (a)].
The polymerizable liquid crystal compound (B) that satisfies all of the above (a) to (e) can be applied, for example, onto an alignment film formed by rubbing treatment and heated to a temperature higher than the phase transition temperature to form a nematic phase. It is possible to do so. In the nematic phase formed by aligning this polymerizable liquid crystal compound (B), the long axes of the polymerizable liquid crystal compound (B) are usually oriented parallel to each other, and this long axis direction is the orientation direction of the nematic phase. becomes.

で表される化合物が挙げられる。前記式（ＩＩ）で表される化合物は単独又は２種以上組合せて使用できる。 The polymerizable liquid crystal compound (B) having the above characteristics generally exhibits reverse wavelength dispersion in many cases. Specifically, as a compound satisfying the above characteristics (a) to (e), for example, the following formula (II):

Examples include compounds represented by: The compounds represented by the formula (II) can be used alone or in combination of two or more.

In formula (II), Ar represents a divalent aromatic group which may have a substituent. The aromatic group referred to herein is a group having a planar cyclic structure, and the number of π electrons in the cyclic structure is [4n+2] according to Huckel's rule. Here, n represents an integer. In the case where a ring structure is formed containing heteroatoms such as -N= and -S-, it also satisfies Huckel's rule including non-covalently bonded electron pairs on these heteroatoms and has aromaticity. Preferably, the divalent aromatic group contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom.

In formula (II), G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a fluoroalkyl group having 1 to 4 carbon atoms. It may be substituted with 1 to 4 alkoxy groups, cyano groups, or nitro groups, and the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group are oxygen atoms, sulfur atoms. Alternatively, it may be substituted with a nitrogen atom.

In formula (II), L ¹ , L ² , B ¹ and B ² are each independently a single bond or a divalent linking group.

In formula (II), k and l each independently represent an integer of 0 to 3, and satisfy the relationship 1≦k+l. Here, when 2≦k+l, B ¹ and B ² and G ¹ and G ² may be the same or different from each other.

In formula (II), E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, where the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom. , -CH ₂ - contained in the alkanediyl group may be substituted with -O-, -S-, or -Si-. P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

In formula (II), G ¹ and G ² are each independently optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms. , 4-phenylenediyl group, 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of halogen atom and alkyl group having 1 to 4 carbon atoms, more preferably methyl A 1,4-phenylenediyl group substituted with a group, an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably an unsubstituted 1,4- A phenylenediyl group or an unsubstituted 1,4-trans-cyclohexanediyl group. Furthermore, at least one of the plurality of G ¹ and G ² is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² More preferably, one is a divalent alicyclic hydrocarbon group.

In formula (II), L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d -, or C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 -, or OCOR ^a6-1 - . Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. L ¹ and L ² are each independently more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or OCO-.

In a preferred embodiment of the present invention, at least one of G ¹ and G ² in formula (II) is a divalent alicyclic hydrocarbon group, and the divalent alicyclic hydrocarbon group is A polymerizable liquid crystal compound is used in which a divalent aromatic group Ar which may have a substituent is bonded to L ¹ and/or L ² which are -COO-.

In formula (II), B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10 -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 -, or R ^a15 OC=OOR ^a16 -. Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 -, or OCOR ^a14-1 - . Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. B ¹ and B ² are each independently, more preferably, a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO-, or OCOCH ₂ CH ₂ - .

In formula (II), k and l preferably have a range of 2≦k+l≦6 from the viewpoint of expressing reverse wavelength dispersion, preferably k+l=4, and more preferably k=2 and l=2. preferable. It is more preferable that k=2 and l=2 because a symmetrical structure is obtained.

In formula (II), E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms.

In formula (II), the polymerizable group represented by P ¹ or P ² includes, for example, an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group. , methacryloyloxy group, oxiranyl group, and oxetanyl group. Among these, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferred, and acryloyloxy group is more preferred.

In formula (II), Ar has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. It is preferable. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, with benzene rings and naphthalene rings being preferred. The aromatic heterocycles include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, and a pyrazole ring. , thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Among these, it is preferable to have a thiazole ring, benzothiazole ring, or benzofuran ring, and it is more preferable to have a benzothiazole group. Further, when Ar includes a nitrogen atom, it is preferable that the nitrogen atom has π electrons.

In formula (II), the total number N _π of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and especially Preferably it is 16 or more. Further, it is preferably 30 or less, more preferably 26 or less, and still more preferably 24 or less.

Examples of the aromatic group represented by Ar include groups of the following formulas (Ar-1) to (Ar-23).

In formulas (Ar-1) to (Ar-23), the mark * represents a connecting part, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 12 carbon atoms. group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 carbon atoms, Alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 12 carbon atoms, or carbon Represents an N,N-dialkylsulfamoyl group having numbers 2 to 12.

In formulas (Ar-1) to (Ar-23), Q ¹ and Q ² are each independently -CR ^2' R ^3' -, -S-, -NH-, -NR ^2' -, - It represents CO- or O-, and R ^2' and R ^3' each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In formulas (Ar-1) to (Ar-23), J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

In formulas (Ar-1) to (Ar-23), Y ¹ , Y ² and Y ³ each independently represent an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

In formulas (Ar-1) to (Ar-23), W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group, or a halogen atom, and m represents an integer of 0 to 6.

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group, and biphenyl group. , naphthyl group is preferred, and phenyl group is more preferred. Examples of the aromatic heterocyclic group include a group having 4 to 20 carbon atoms and containing at least one heteroatom such as a nitrogen atom, an oxygen atom, or a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group. Examples include aromatic heterocyclic groups, and furyl, thienyl, pyridinyl, thiazolyl, and benzothiazolyl groups are preferred.

Y ¹ and Y ² may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

In formulas (Ar-1) to (Ar-23), Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, It is preferably an alkoxy group having 1 to 12 carbon atoms, Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are a hydrogen atom, a fluorine atom, or a chlorine atom. More preferred are atoms, methyl groups, and cyano groups.

In formulas (Ar-1) to (Ar-23), Q ¹ and Q ² are preferably -NH-, -S-, -NR ^2' -, -O-, and R ^2' is preferably a hydrogen atom . Among them, -S-, -O-, and -NH- are particularly preferred.

Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability.

In formulas (Ar-17) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples of the aromatic heterocyclic group include those mentioned above as aromatic heterocycles that Ar may have, such as a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and an indole ring. ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. This aromatic heterocyclic group may have a substituent. Further, Y ¹ may be the aforementioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group, together with the nitrogen atom to which it is bonded and Z ⁰ . Examples include a benzofuran ring, a benzothiazole ring, a benzoxazole ring, and the like. Note that the compound represented by the formula (II) can be produced, for example, according to the method described in JP-A-2010-31223.

The content of the polymerizable liquid crystal compound (B) in the polymerizable liquid crystal composition (B) constituting the retardation film is, for example, 70 to 99 parts by mass based on 100 parts by mass of the solid content of the polymerizable liquid crystal composition (B). .5 parts by weight, preferably 80 to 99 parts by weight, more preferably 90 to 98 parts by weight. When the content is within the above range, the orientation of the retardation film tends to be high. Here, the solid content refers to the total amount of components excluding volatile components such as solvents from the polymerizable liquid crystal composition (B).

The polymerizable liquid crystal composition (B) may contain a polymerization initiator for starting the polymerization reaction of the polymerizable liquid crystal compound (B). The polymerization initiator can be appropriately selected from those conventionally used in the field, and may be a thermal polymerization initiator or a photopolymerization initiator, but it can be used under lower temperature conditions. A photopolymerization initiator is preferred because it can initiate a polymerization reaction. Suitable photopolymerization initiators that can be used in the polarizer-forming composition include those similar to those exemplified above. Furthermore, the polymerizable liquid crystal composition (B) may contain, as necessary, a photosensitizer, a leveling agent, and the additives listed as additives contained in the polarizer-forming composition. . Examples of the photosensitizer and leveling agent include the same ones as those exemplified above as those that can be used in the composition for forming a polarizer.

The polymerizable liquid crystal composition (B) is prepared, for example, by mixing and stirring the polymerizable liquid crystal compound (B) and, if necessary, a polymerization initiator, additives, and the like. Furthermore, in order to improve the coating properties, a solvent may be added to the polymerizable liquid crystal composition (B) to adjust the viscosity. Examples of the solvent include the solvents exemplified above as solvents contained in the polarizer-forming composition.

The retardation film is produced by coating the polymerizable liquid crystal composition (B) on a base material or an alignment film, removing the solvent by drying, and heating and/or heating the polymerizable liquid crystal compound (B) in the resulting coating film. Alternatively, it can be obtained by curing with active energy rays. Examples of the alignment film include those similar to those exemplified above as those that can be used when producing the polarizer of the present invention.

The solvent used in the composition for forming a retardation film, the method for applying the composition for forming a retardation film, the curing conditions using active energy rays, etc. are all the same as those that can be adopted in the method for producing a polarizer of the present invention. Things can be mentioned.

The thickness of the retardation film can be appropriately selected depending on the display device to which it is applied, but from the viewpoint of thinning and flexibility, it is preferably 0.1 to 10 μm, more preferably 1 to 5 μm. , more preferably 1 to 3 μm.

The polarizing plate in the present invention may include a polarizing film, a retardation film, and an adhesive layer or a layer other than the adhesive layer, such as a protective film. In a preferred embodiment, the polarizing plate of the present invention has a polarizing film and a retardation film bonded to each other via an adhesive layer or a pressure-sensitive adhesive layer.

The thickness of the polarizing plate of the present invention is preferably 1 to 100 μm, more preferably 2 to 70 μm, and still more preferably 3 to 60 μm from the viewpoint of flexibility and visibility of the display device.

The polarizing film or polarizing plate of the present invention may include a front plate. FIG. 1 shows a schematic cross-sectional view of the layer structure of a polarizing film with a front plate in one embodiment of the present invention. In the polarizing film with front plate 1 , a front plate 3 is formed on a first resin layer 4 of a polarizing film 2 . In the polarizing film 2, a first resin layer 4, a polarizer 5, an alignment film 6, and a second resin layer 7 are laminated in this order from the front plate 3 side. The polarizing film 1 with a front plate can provide surface hardness and light resistance by providing the front plate. In addition, in the polarizing film 1 with a front plate, an adhesive layer or an adhesive layer may be formed between the front plate 3 and the first resin layer 4.

FIG. 2 shows a schematic cross-sectional view of the layer structure of a polarizing plate with a front plate in an embodiment of the present invention. In the polarizing plate 8 with a front plate, a front plate 3 is formed on a polarizing plate 9. The polarizing plate 9 has a first resin layer 4, a polarizer 5, an alignment film 6, a second resin layer 7, and a retardation film 10 laminated in this order from the front plate 3 side. The polarizing plate 8 with a front plate can provide surface hardness and light resistance by providing the front plate. In addition, in the polarizing plate 8 with a front plate, an adhesive layer or an adhesive layer is formed between the front plate 3 and the first resin layer 4 and/or between the second resin layer 7 and the retardation film 10. may have been done. Note that in FIGS. 1 and 2, the dimensions and ratios of each layer are changed as appropriate to make the drawings easier to see.

FIG. 3 shows a schematic cross-sectional view of the layer structure of a polarizing film with a front plate in another embodiment of the present invention. In the polarizing film with front plate 11, the front plate 3 is formed on the second resin layer 7 of the polarizing film 2. In the polarizing film 2, a second resin layer 7, an alignment film 6, a polarizer 5, and a first resin layer 4 are laminated in this order from the front plate 3 side. The polarizing film 11 with a front plate can provide surface hardness and light resistance by providing the front plate. In addition, in the polarizing film 11 with a front plate, an adhesive layer or an adhesive layer may be formed between the front plate 3 and the second resin layer 7.

FIG. 4 shows a schematic cross-sectional view of the layer structure of a polarizing plate with a front plate in another embodiment of the present invention. In the polarizing plate 12 with a front plate, a front plate 3 is formed on a polarizing plate 13. In the polarizing plate 13, the second resin layer 7, the alignment film 6, the polarizer 5, the first resin layer 4, and the retardation film 10 are laminated in this order from the front plate 3 side. The polarizing plate 13 with a front plate can provide surface hardness and light resistance by providing the front plate. In addition, in the polarizing plate 13 with a front plate, an adhesive layer or an adhesive layer is formed between the front plate 3 and the second resin layer 7 and/or between the first resin layer 4 and the retardation film 10. may have been done. Note that in FIGS. 3 and 4, the dimensions and ratios of each layer are changed as appropriate to make the drawings easier to see.

<Display device>
The polarizing film of the present invention or the polarizing plate can be applied to display devices. The display device can be obtained, for example, by laminating the polarizing film of the present invention or the polarizing plate on the surface of the display device via a pressure-sensitive adhesive layer or an adhesive layer. A display device is a device having a display mechanism, and includes a light emitting element or a light emitting device as a light source. Display devices include liquid crystal display devices, organic electroluminescent (EL) display devices, inorganic electroluminescent (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FEDs, etc.), surface field emission display devices) (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection type display device (grating light valve (GLV) display device, display device with digital micromirror device (DMD)) etc.) and piezoelectric ceramic displays. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct view type liquid crystal display device, a projection type liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images or stereoscopic display devices that display three-dimensional images. In particular, as the display device of the present invention, an organic EL display device and a touch panel display device are preferable, and an organic EL display device is particularly preferable.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Hereinafter, parts and percentages representing amounts used and contents are based on mass unless otherwise specified.

<Evaluation of adhesion>
The surface of the second resin layer of the polarizing film obtained in Examples and Comparative Examples was bonded to glass via a pressure-sensitive adhesive, and cellophane tape was pasted on the surface of the first resin layer opposite to the glass surface. A peel test was conducted to evaluate the adhesion of the polarizing film. The case where a peeling phenomenon could be confirmed inside the polarizing film was rated as "x", and the case where no peeling phenomenon could be confirmed was rated as "○".

<Evaluation of heat resistance>
The degree of polarization Py and the single transmittance Ty of the polarizing films obtained in Examples and Comparative Examples were measured as follows. The transmittance (Ta) in the transmission axis direction and the transmittance (Tb) in the absorption axis direction in the wavelength range of 380 nm to 780 nm were measured using a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation) equipped with a folder with a polarizer. It was measured using the double beam method. A mesh was installed on the reference side of the folder to cut off the amount of light by 50%.
Using the following formulas (Formula 1) and (Formula 2), calculate the single transmittance and degree of polarization at each wavelength, and then perform visibility correction using the 2-degree field of view (C light source) of JIS Z 8701. Single transmittance (Ty) and visibility correction polarization degree (Py) were calculated.
Single transmittance Ty (%) = (Ta+Tb)/2 (Formula 1)
Polarization degree Py (%) = (Ta-Tb)/(Ta+Tb)×100 (Formula 2)

After heating the polarizing films obtained in Examples and Comparative Examples for 240 hours at 85°C dry conditions, the degree of polarization Py and single transmittance Ty of the polarizing films were measured again, and the change in Py before and after the heat resistance test ΔPy (= Py after the heat resistance test - Py before the heat resistance test) and the amount of change ΔTy in Ty before and after the heat resistance test (=Ty after the heat resistance test - Ty before the heat resistance test) were calculated.

<Evaluation of flexibility>
The evaluation of flexibility was carried out as follows using the method of General Test Methods for Paints - Flexibility (Cylindrical Mandrel Method) described in JIS-K-5600-5-1.
The polarizing films obtained in Examples and Comparative Examples were cut into 25 mm x 200 mm squares, and the cut films were tested at a temperature of 25°C using a cylindrical mandrel bending resistance tester type II (manufactured by TP Giken Co., Ltd.). A flexibility test was conducted by winding the first resin layer forming composition around a mandrel rod having a diameter of 4 mm (bending radius R = 2 mm) under conditions of relative humidity 55% RH, with the cured layer of the composition for forming the first resin layer facing outside. The film after the test was visually checked under transmitted light in a dark room environment to observe the occurrence of cracks. Those with visible cracks were marked with an "x", and those with no visible cracks were marked as "x". It was judged as "○".

<Thickness of each layer>
The thicknesses of the polarizer, alignment film, first resin layer, and second resin layer were measured using a laser microscope (OLS3000 manufactured by Olympus Corporation).

[Production Examples 1 to 9]
<Preparation of resin layer forming compositions (A) to (I)>
Each component listed in Table 1 was mixed and stirred at 50° C. for 4 hours to obtain resin layer forming compositions (A) to (I), respectively.

[Manufacture example 10]
<Preparation of resin layer forming composition (J)>
A resin layer forming composition (J) was obtained by mixing the following components and stirring at 23° C. for 4 hours.
(Components of resin layer forming composition (J))
・Celoxide 2021P: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (manufactured by Daicel Chemical Co., Ltd.) 70 parts ・2-ethylhexyl glycidyl ether 30 parts ・CPI-100P: triarylsulfonium hexafluorophosphate 50% propylene carbonate solution (manufactured by Sun-Apro Co., Ltd.) 2.5 parts/SH710: Silicone leveling agent (manufactured by Toray Dow Corning Co., Ltd.) 0.25 parts

[Manufacture example 11]
<Preparation of resin layer forming composition (K)>
A resin layer forming composition (K) was obtained by mixing the following components and stirring at 23° C. for 4 hours.
(Components of resin layer forming composition (K))
・Celoxide 2021P: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (manufactured by Daicel Chemical Co., Ltd.) 32.5 parts ・EHPE3150: 1 of 2,2-bis(hydroxymethyl)-1-butanol ,2-epoxy-4-(2-oxiranyl)cyclohexane adduct (manufactured by Daicel Chemical Co., Ltd.) 17.5 parts・OXT-221: Bis(3-ethyl-3-oxetanylmethyl)ether (Toagosei Co., Ltd.) 50 parts CPI-100P: 50% propylene carbonate solution of triarylsulfonium hexafluorophosphate (manufactured by San-Apro Co., Ltd.) 2.5 parts SH710: Silicone leveling agent (manufactured by Dow Corning Toray Co., Ltd.) 0 .25 copies

[Manufacture example 12]
<Preparation of resin layer forming composition (L)>
An acetoacetylated modified polyvinyl alcohol resin (Gosefimer Z200, manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., degree of saponification: 98.5 mol% or more) is dissolved in pure water by stirring at 90 ° C. for 4 hours, A 5% strength by weight aqueous solution was prepared. The above polyvinyl alcohol resin aqueous solution and a 10% by weight aqueous solution of sodium glyoxylate were mixed so that the solid content weight ratio of acetoacetyl group-modified polyvinyl alcohol resin:sodium glyoxylate was 1:0.1, and then water was added. A resin layer forming composition (L) was prepared by diluting with pure water so that the solid content weight ratio of the polyvinyl alcohol resin to 100 parts was 3.0 parts.

Each component in Table 1 is shown below.
Polyfunctional acrylate monomer (1): Dipentaerythritol hexaacrylate (manufactured by Shin Nakamura Chemical Co., Ltd., "NK Ester A-DPH"), the branch point closest to the (meth)acryloyl group in the branched structure, and the (meth) ) The number of atoms in the chain connecting the acryloyl group is 2.

Polyfunctional acrylate monomer (2): ethylene oxide (6 pieces) dipentaerythritol hexaacrylate (manufactured by Shin Nakamura Chemical Co., Ltd., "NK Ester A-DPH-6E"), (meth)acryloyl group in the branched structure The number of atoms in the chain connecting the nearest branch point and the (meth)acryloyl group is 5.

Polyfunctional acrylate monomer (3): ethylene oxide (12 pieces) dipentaerythritol hexaacrylate (manufactured by Shin Nakamura Chemical Co., Ltd., "NK Ester A-DPH-12E"), (meth)acryloyl group in the branched structure The number of atoms in the chain connecting the nearest branch point and the (meth)acryloyl group is 8.

Polyfunctional acrylate monomer (4): Tripentaerythritol octaacrylate (manufactured by Koei Chemical Co., Ltd., "TPEA"), the branch point closest to the (meth)acryloyl group in the branched structure and the (meth)acryloyl group The number of atoms in the connected chains is 2.

Urethane acrylate polymer (1): Urethane acrylate (manufactured by Daicel Allnex Corporation, "Evecryl 4858"), the number of functional groups is 2, the weight average molecular weight Mw is 450, the number of functional groups per unit molecular weight is 44.4 × 10 ^- It is ⁴ .

Urethane acrylate polymer (2): Urethane acrylate (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., "Shikou UV-7650"), the number of functional groups is 4 to 5, the weight average molecular weight Mw is 2300, the number of functional groups per unit molecular weight is 19 .6×10 ⁻⁴ .

Radical polymerization initiator (1): phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (manufactured by BASF, "Irgacure 819")
Radical polymerization initiator (2): 1-hydroxycyclohexylphenyl ketone (manufactured by BASF, "Irgacure 184")
Radical polymerization initiator (3): 2-[4-(methylthio)benzoyl]-2-(4-morpholinyl)propane (manufactured by BASF, "Irgacure 907")

Solvent (1): Methyl ethyl ketone

・二色性色素：
アゾ色素；

・光重合開始剤：
２－ジメチルアミノ－２－ベンジル－１－（４－モルホリノフェニル）ブタン－１－オン（イルガキュア３６９；チバ・スペシャルティ・ケミカルズ(株)製） ６部
・レベリング剤：
ポリアクリレート化合物（ＢＹＫ－３６１Ｎ；ＢＹＫ－Ｃｈｅｍｉｅ社製） １．２部
・溶剤：
ｏ－キシレン ４００部 [Manufacture example 13]
<Preparation of composition for forming polarizing film>
A composition for forming a polarizing film was obtained by mixing the following components and stirring at 80° C. for 1 hour. As the dichroic dye, an azo dye described in Examples of JP-A-2013-101328 was used.
・Polymerizable liquid crystal compound:

・Dichroic dye:
Azo dye;

・Photopolymerization initiator:
2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals Co., Ltd.) 6 parts Leveling agent:
Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 parts/Solvent:
o-xylene 400 parts

[Example 1]
(1) Preparation of second resin layer After corona treatment is applied to the release-treated surface of a polyethylene terephthalate film (SP-PLR382050 manufactured by Lintec Corporation) (release film) that has been subjected to mold release treatment, a second hardening layer is applied. The resin layer forming composition (A) was applied as a composition by a bar coating method (#2 30 mm/s), and an exposure amount of 500 mJ was applied using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.). A release film with a resin layer in which a second resin layer was formed on the surface of the release film was obtained by irradiating the coating layer of the composition for forming a resin layer with ultraviolet rays of /cm ² (365 nm standard). The thickness of the second resin layer was 1.5 μm.

・溶剤：
ｏ－キシレン ９８部 (2) Preparation of photo-alignment film (i) Preparation of composition for forming photo-alignment film By mixing the following components described in JP-A-2013-033249 and stirring the resulting mixture at 80 ° C. for 1 hour, A composition for forming a photo-alignment film was obtained.
・Photoalignable polymer:

·solvent:
o-xylene 98 parts

(ii) Formation of photo-alignment film Next, after corona treatment is applied to the surface of the second resin layer of the release film with a resin layer, a composition for forming a photo-alignment film is applied and dried at 120°C. A dry film was obtained. A photo-alignment film was formed by irradiating polarized UV on this dry film to obtain a laminate A having a release film, a second resin layer, and a photo-alignment film in this order. The polarized UV treatment was performed using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.) under conditions where the intensity measured at a wavelength of 365 nm was 100 mJ. The thickness of the photo-alignment film was 100 nm.

(3) Preparation of polarizer A composition for forming a polarizing film was coated on the surface of the photo-alignment film of the laminate A obtained as described above by a bar coating method (#9 30 mm/s), and dried at 120°C. The polymerizable liquid crystal compound was subjected to a phase transition to a liquid phase by heating and drying in an oven for 1 minute, and then cooled to room temperature to cause a phase transition of the polymerizable liquid crystal compound to a smectic liquid crystal state. Next, using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.), the layer formed from the composition for forming a polarizing film is irradiated with ultraviolet rays with an exposure amount of 1000 mJ/cm ² (365 nm standard). Thereby, the polymerizable liquid crystal compound contained in the dry film was polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizer (polarizing film) was formed from the dry film. The thickness of the polarizer was 2.3 μm. In this way, a laminate B having a release film, a second resin layer, a photo-alignment film, and a polarizer in this order was obtained. Similar X-ray diffraction measurements were performed on this polarizer using an X-ray diffraction device X'Pert PRO MPD (manufactured by Spectris Co., Ltd.). ) = approximately 0.17° sharp diffraction peak (Bragg peak) was obtained. The order period (d) determined from the peak position was approximately 4.4 Å, and it was confirmed that a structure reflecting a higher-order smectic phase was formed.

(4) Preparation of the first resin layer After corona treatment is applied to the surface of the polarizer of the laminate B obtained as described above, the resin layer forming composition (A) is added as the first curable composition. The resin was coated again using the bar coating method (#2 30 mm/s), and UV irradiation at an exposure amount of 500 mJ/cm ² (365 nm standard) was applied to the resin using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.). By irradiating the coating layer of the layer-forming composition, a laminate C having a release film, a second resin layer, a photo-alignment film, a polarizer, and a first resin layer in this order was obtained. Next, the release film was peeled off to obtain a polarizing film having the second resin layer, the optical alignment film, the polarizer, and the first resin layer in this order. Note that the thickness of the first resin layer was 1.5 μm.

[Examples 1 to 9 and Comparative Examples 1 and 2]
As shown in Table 2, in the same manner as in Example 1, except that the resin layer forming compositions (B) to (K) were used in place of the resin layer forming composition (A), Polarizing films of Examples 1 to 9 and Comparative Examples 1 and 2 were obtained.

[Comparative example 3]
(1) Preparation of second resin layer After corona treatment is applied to the release-treated surface of a polyethylene terephthalate film (SP-PLR382050 manufactured by Lintec Corporation) (release film) that has been subjected to mold release treatment, a second hardening layer is applied. A second resin layer was formed on the surface of the release film by applying the resin layer forming composition (L) as a composition by bar coating method (#30 30 mm/s) and drying at 100 ° C. for 1 minute. A release film with a resin layer was obtained. The thickness of the second resin layer was 1.5 μm.

(2) Preparation of photo-alignment film Next, after corona treatment is applied to the surface of the second resin layer of the release film with a resin layer, a composition for forming a photo-alignment film is applied and dried at 120°C. A dry film was obtained. A photo-alignment film was formed by irradiating polarized UV on this dry film to obtain a laminate K having a release film, a second resin layer, and a photo-alignment film in this order. The polarized UV treatment was performed using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.) under conditions where the intensity measured at a wavelength of 365 nm was 100 mJ. The thickness of the photo-alignment film was 100 nm.

(3) Preparation of polarizer A composition for forming a polarizing film was coated on the surface of the photo-alignment film of the laminate K obtained as described above by a bar coating method (#9 30 mm/s), and dried at 120°C. The polymerizable liquid crystal compound was subjected to a phase transition to a liquid phase by heating and drying in an oven for 1 minute, and then cooled to room temperature to cause a phase transition of the polymerizable liquid crystal compound to a smectic liquid crystal state. Next, using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.), the layer formed from the composition for forming a polarizing film is irradiated with ultraviolet rays with an exposure amount of 1000 mJ/cm ² (365 nm standard). Thereby, the polymerizable liquid crystal compound contained in the dry film was polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizer (polarizing film) was formed from the dry film. The thickness of the polarizer was 2.3 μm. In this way, a laminate L having a release film, a second resin layer, a photo-alignment film, and a polarizer in this order was obtained.

(4) Preparation of the first resin layer After corona treatment is applied to the surface of the polarizer of the laminate L obtained as described above, the resin layer forming composition (L) is added as the first curable composition. By applying it again using the bar coating method (#30 30 mm/s) and drying it at 100°C for 1 minute, the mold release film, second resin layer, photo-alignment film, polarizer, and first resin layer are formed in this order. A laminate M was obtained. Next, the release film was peeled off to obtain a polarizing film having the second resin layer, the optical alignment film, the polarizer, and the first resin layer in this order. Note that the thickness of the first resin layer was 1.5 μm.

The polarizing films obtained in Examples 1 to 9 and Comparative Examples 1 to 3 were evaluated for adhesion and heat resistance. The results are shown in Table 2.

The polarizing films obtained in Example 5 and Example 8 were evaluated for flexibility. As a result, no cracks occurred in either case, and the evaluation was ○.

As shown in Table 2, the polarizing films obtained in Examples 1 to 9 and Comparative Examples 1 to 3 gave the results of the adhesion evaluation as ○, confirming that they had excellent interlayer adhesion. It was also confirmed that ΔTy and ΔPy, which are the changes in Ty and Py before and after the heat resistance test, were close to 0, indicating excellent heat resistance. On the other hand, the polarizing films obtained in Comparative Examples 1 to 3 had poor adhesion, with the result of evaluation of adhesion being x.
Furthermore, the polarizing films obtained in Examples 5 and 8 had a flexibility evaluation of ◯, and were found to have excellent flexibility in addition to adhesion and heat resistance.

1, 11...Polarizing film with front plate,
2... Polarizing film 3... Front plate 4... First resin layer 5... Polarizer 6... Alignment film 7... Second resin layer 8, 12... Polarizing plate with front plate 9, 13... Polarizing plate 10... Retardation film

Claims (8)

A polarizing film in which a first resin layer, a polarizer, an alignment film, and a second resin layer are stacked adjacent to each other in this order,
The first resin layer is a cured product of a first curable composition containing a (meth)acrylic compound,
The polarizer is a cured product of a polarizer-forming composition containing a polymerizable liquid crystal compound having a (meth)acryloyl group and a dichroic dye,
The alignment film is a cured product of a composition for forming an alignment film containing a (meth)acrylic compound,
The second resin layer is a cured product of a second curable composition containing a (meth)acrylic compound,
A polarizing film in which the first curable composition and the second curable composition contain a radical polymerization initiator. The polarizing film according to claim 1, wherein at least one of the first curable composition and the second curable composition contains a urethane (meth)acrylate compound as the (meth)acrylic compound. The polarizing film according to claim 2, wherein the urethane (meth)acrylate compound has a number of (meth)acryloyl groups per unit molecular weight of 15×10 ⁻⁴ or more. The polarizing film according to any one of claims 1 to 3, wherein at least one of the first curable composition and the second curable composition contains a polyfunctional (meth)acrylate compound as the (meth)acrylic compound. The polarizing film according to claim 4, wherein the number of (meth)acryloyl groups in the polyfunctional (meth)acrylate compound is 6 or more. The polyfunctional (meth)acrylate compound has a branched structure, and the number of atoms in the chain connecting the branch point closest to the (meth)acryloyl group in the branched structure and the (meth)acryloyl group is 3 or less. The polarizing film according to claim 4 or 5. A first curable composition is applied or superimposed on the polarizer surface of a laminate in which a second resin layer, an alignment film, and a polarizer are stacked adjacent to each other in this order, and the first curable composition is cured. The method for producing a polarizing film according to any one of claims 1 to 6, comprising the step of: The first curable composition formed on the release film is superimposed on the polarizer surface of a laminate in which the second resin layer, the alignment film, and the polarizer are laminated adjacent to each other in this order, and the mold is released. By curing the first curable composition by irradiating active energy rays from the film side, the release film, first resin layer, polarizer, alignment film, and second resin layer are laminated adjacent to each other in this order. The method for producing a polarizing film according to any one of claims 1 to 6, comprising the steps of obtaining a laminate and peeling a release film from the laminate.

Images