JP2019133151A - Polarizing film-forming composition - Google Patents

Abstract

To provide a polarizing film-forming composition which features superior long-term storage stability and effectively prevents a polarizing film produced therefrom from having alignment defects even after being stored for a prolonged period of time.SOLUTION: A polarizing film-forming composition contains a polymerizable liquid crystal compound, dichroic pigment, photopolymerization initiator, and organic solvent, and satisfies the following expression (1): A(380)≥1.2 ...(1), where A(380) represents an absorbance, at 380 nm, of a solution obtained by diluting the polarizing film-forming composition with the organic solvent to a concentration of 0.4 mass%.SELECTED DRAWING: None

Description

  The present invention relates to a polarizing film forming composition containing a polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent, a polarizing film, a method for producing the polarizing film, and a polarizing plate.

  Optical films such as polarizing plates and retardation plates are used in flat panel display devices (FPD). In recent years, from the viewpoint of thinning, a polarizing plate including a polarizing film obtained by curing a composition containing a polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent has been studied (for example, Patent Documents). 1).

JP 2012-083734 A

In order to continuously form such a polarizing film, it is necessary to prepare a polarizing film-forming composition containing a polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent and store it for a long time. . However, according to the study by the present inventors, the composition for forming a polarizing film generates radicals when the photopolymerization initiator is irradiated with light during long-term storage. Since the polymerizable liquid crystal compound in the composition reacts with the radicals generated in this manner, it has been found that alignment defects may occur when the polymerizable liquid crystal compound is cured in an aligned state after storage.
Accordingly, an object of the present invention is to provide a composition for forming a polarizing film that has excellent long-term storage stability and can effectively suppress the occurrence of alignment defects in the obtained polarizing film even after long-term storage. .

  As a result of intensive studies to solve the above problems, the present inventor has identified an absorbance at 380 nm in a composition for forming a polarizing film containing a polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent. If it is in the range of this, it discovered that the said subject could be solved and came to complete this invention. That is, the present invention includes the following.

[1] A polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent, and the following formula (1)
A (380) ≧ 1.2 (1)
[Wherein, A (380) represents the absorbance at 380 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
The composition for polarizing film formation which satisfy | fills.
[2] Further, the following formula (2)
0.8 ≧ A (650) (2)
[Wherein A (650) represents the absorbance at 650 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
The composition for forming a polarizing film according to [1], wherein
[3] The composition for forming a polarizing film according to [1] or [2], wherein the polymerizable liquid crystal compound is a compound exhibiting smectic liquid crystallinity.
[4] The polarizing film according to any one of [1] to [3], wherein the solid content in the polarizing film-forming composition is 5 to 50% by mass of the mass of the polarizing film-forming composition. Forming composition.
[5] The composition for forming a polarizing film according to any one of [1] to [4], wherein the content of the polymerizable liquid crystal compound is 50 to 99% by mass of the solid content in the composition for forming a polarizing film. object.
[6] The composition for forming a polarizing film according to any one of [1] to [5], wherein the content of the dichroic dye is 1 to 20% by mass of the mass of the solid content in the composition for forming a polarizing film. object.
[7] A polarizing film, which is a cured product of the composition for forming a polarizing film according to any one of [1] to [6].
[8] Step (ii) of forming a coating film of the composition for forming a polarizing film according to any one of [1] to [6], drying and removing the organic solvent from the coating film, and a polymerizable liquid crystal compound The manufacturing method of a polarizing film including the process (iii) of carrying out orientation hardening in the state of a smectic liquid crystal phase.
[9] including a step (i) of storing the polarizing film-forming composition according to any one of [1] to [6] in a state satisfying the formula (1) and / or (2). ] Method.
[10] A polarizing plate comprising the polarizing film according to [7], a substrate, and a photo-alignment film.

  The composition for forming a polarizing film of the present invention is excellent in long-term storage stability and can effectively suppress the occurrence of alignment defects in the obtained polarizing film even after long-term storage.

<Polarization film forming composition>
The composition for forming a polarizing film of the present invention contains a polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent.
A (380) ≧ 1.2 (1)
[Wherein, A (380) represents the absorbance at 380 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
Meet. When the absorbance at 380 nm of the composition for forming a polarizing film is within a specific range, when the composition is stored, the radical generation of the photopolymerization initiator and the polymerization reaction of the polymerizable liquid crystal compound by the radical are effectively performed. Can be suppressed or prevented. Therefore, the composition for forming a polarizing film of the present invention causes little or no alignment defect even when the polymerizable liquid crystal compound in the composition is polymerized in an aligned state. Therefore, the composition for forming a polarizing film of the present invention is excellent in long-term storage stability and can form a polarizing film having excellent orientation even after long-term storage.

  In the formula (1), the value of A (380) is preferably 1.4 or more, more preferably 1.6 or more. When A (380) in Formula (1) is not less than the above value, polymerization (polymerization) of the polymerizable liquid crystal compound can be more effectively suppressed or prevented, and the long-term storage stability of the composition for forming a polarizing film can be further improved. Can be improved. Moreover, the value of A (380) in Formula (1) is 4.0 or less normally, Preferably it is 3.5 or less. When the formula (1) is not more than the above value, precipitation of dichroic dye and the like are reduced.

The composition for forming a polarizing film of the present invention further comprises the following formula (2):
0.8 ≧ A (650) (2)
[Wherein A (650) represents the absorbance at 650 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
It is preferable to satisfy. When the absorbance at 650 nm of the composition for forming a polarizing film is 0.8 or less, a part of visible light (particularly red light) is transmitted without being absorbed by the composition for forming a polarizing film. If there is foreign matter such as dust or undissolved residue of dichroic dye or the like in the composition, it can be visually confirmed. Therefore, such foreign matters and undissolved residues can be easily removed from the polarizing film forming composition, and the occurrence of alignment defects due to the foreign materials and undissolved residues can be effectively suppressed or prevented.
On the other hand, it is preferable that the polarizing film can cut visible light from the viewpoint of polarization performance. In one embodiment of the present invention, the composition for forming a polarizing film transmits light of 650 nm as described above in a state before curing, but when cured to form a polarizing film, the maximum absorption wavelength is on the long wavelength side. The light of 650 nm is cut by the effect of shifting to (in some cases, red shifting). Thus, the composition for forming a polarizing film of the present invention has an advantage that foreign matters can be visually observed before curing, and has an advantage that polarization performance can be secured after curing. When the polarizing film forming composition is cured to form a polarizing film, the red shift is caused by the inclusion of the dichroic dye in the liquid crystal in which the polymerizable liquid crystal compound is cured in an aligned state (sometimes referred to as polymerized liquid crystal). As a result, the distance between the polymerized liquid crystal and the dichroic dye is reduced, the electron density is increased, and it is estimated that the mutual interaction occurs.

  Here, in the solution for measuring the absorbance at 380 nm and 650 nm, the concentration (mass%) of the composition for forming a polarizing film is based on the total mass (100 mass%) of the composition for forming a polarizing film and the organic solvent for dilution. It represents the mass (content) of the composition for forming a polarizing film. The absorbance at 380 nm and 650 nm can be measured using a spectrophotometer by putting the composition for forming a polarizing film into a quartz cell so that the optical path length is 1 cm, and can be measured by, for example, the method described in Examples. In addition, the organic solvent for measuring the absorbance is the same as the organic solvent in the polarizing film forming composition.

  In the formula (2), the value of A (650) is preferably 0.7 or less, and more preferably 0.5 or less. When A (650) in the formula (2) is not more than the above value, light at 650 nm can easily pass through the composition for forming a polarizing film, and foreign matter and undissolved residue can be more easily confirmed visually. The value of A (650) is usually 0.4 or more. When A (650) in the formula (2) is not less than the above value, it is easy to improve the polarization performance of the obtained polarizing film.

The composition for forming a polarizing film of the present invention further comprises the following formula (3):
A (400-600) ≧ 1.0 (3)
[Wherein, A (400 to 600) represents the absorbance at 400 to 600 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
It is preferable to satisfy. If the relationship of Formula (3) is satisfied, it is easy to improve the polarization performance of the obtained polarizing film. The value of A (400 to 600) is usually 4.0 or less, preferably 3.5 or less. The absorbance at a wavelength of 400 to 600 nm can be measured by the same method as the absorbance at 380 nm and 650 nm.

  In a preferred embodiment of the present invention, the polarizing film-forming composition satisfies the above formulas (1) to (3). Such a composition for forming a polarizing film is excellent in long-term storage stability and allows visual confirmation of contamination of foreign matters and the like, so that alignment defects of the obtained polarizing film can be effectively suppressed and sufficient polarizing performance can be ensured. The color of such a composition for forming a polarizing film may be a slightly reddish black, but the resulting polarizing film has an effect of increasing the absorbance near 650 nm due to red shift compared to the composition for forming a polarizing film. And it can be black without redness.

[Polymerizable liquid crystal compound]
The polymerizable liquid crystal composition of the present invention comprises a polymerizable liquid crystal compound having at least one polymerizable group and exhibiting smectic liquid crystallinity (hereinafter also referred to as “polymerizable liquid crystal compound (B)”). By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizing film having a high degree of alignment order can be formed. The liquid crystal state exhibited by the polymerizable liquid crystal compound (B) is a smectic phase (smectic liquid crystal state), and is more preferably a higher order smectic phase (higher order smectic liquid crystal state) from the viewpoint of realizing a higher degree of alignment order. preferable. The higher order smectic phase means 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, a smectic B phase, a smectic F phase, and a smectic I phase are more preferable. A polarizing film having 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 the surface periodic structure of molecular orientation, and a polarizing film having a periodic interval of 3.0 to 6.0 mm is preferable. A polymerizable liquid crystal compound exhibiting smectic liquid crystallinity (a polymerizable liquid crystal compound having a smectic phase) is referred to as a polymerizable smectic liquid crystal compound.

  When a polymerizable smectic liquid crystal compound is contained in the composition for forming a polarizing film of the present invention, a smectic phase is formed in the resulting polarizing film. In the smectic phase state, the dichroic dye contained in the liquid crystal and the aligned polymerized liquid crystal are aligned at closer positions, so that the electron density is more likely to be improved, and is likely to shift to the longer wavelength side after curing. . Therefore, the absorbance at 650 nm after forming the polarizing film is likely to increase, and the polarizing performance of the obtained polarizing film can be further improved.

The polymerizable liquid crystal compound (B) includes a compound represented by the formula (B1) and a polymer of the compound (hereinafter, the compound and the polymer are collectively referred to as “polymerizable liquid crystal compound (B1)”. There are).
^{U 1 -V 1 -W 1 -X 1} -Y 1 -X 2 -Y 2 -X 3 -W 2 -V 2 -U 2 (B1)
[In the formula (B1),
X ¹ , X ² and X ³ each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the divalent aromatic group or divalent alicyclic group The hydrogen atom contained in the hydrocarbon group is 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. The carbon atom constituting the divalent aromatic group or 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 , X ² and X ³ is a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. It is.
Y ¹ and Y ² are each independently a single bond or a divalent linking group.
U ¹ represents a hydrogen atom or a polymerizable group.
U ² represents a polymerizable 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 optionally substituted alkanediyl group having 1 to 20 carbon atoms, and —CH ₂ — constituting the alkanediyl group is —O—, — CO-, -S- or NH- may be substituted. ]

In the polymerizable liquid crystal compound (B1), at least one of X ¹ , X ² and X ³ may have a 1,4-phenylene group which may have a substituent, or a substituent. A good cyclohexane-1,4-diyl group. In particular, X ¹ and X ³ are preferably a cyclohexane-1,4-diyl group which may have a substituent, and the cyclohexane-1,4-diyl group is trans-cyclohexane- More preferably, it is a 1,4-diyl group. Examples of the substituent that the optionally substituted 1,4-phenylene group or the optionally substituted cyclohexane-1,4-diyl group include a methyl group, ethyl Group, a C1-C4 alkyl group such as a butyl group, a cyano group, and a halogen atom such as a chlorine atom and a fluorine atom. Preferably it is unsubstituted. Further, when Y ¹ and Y ² have the same structure, it is preferable that at least one of X ¹ , X ² and X ³ is a different structure. When at least one of X ¹ , X ² and X ³ has a different structure, smectic liquid crystallinity tends to be easily exhibited.

Y ¹ and Y ² each independently represent —CH ₂ CH ₂ —, —CH ₂ O—, —CH ₂ CH ₂ O—, —COO—, —OCOO—, a 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. Y ¹ is more preferably —CH ₂ CH ₂ —, —COO— or a single bond, and Y ² is more preferably —CH ₂ CH ₂ — or CH ₂ O—. When X ¹ , X ² and X ³ all have the same structure, it is preferable that Y ¹ and Y ² have different structures. When Y ¹ and Y ² have different structures, smectic liquid crystallinity tends to be easily exhibited.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, and preferably a polymerizable group. U ¹ and U ² are preferably both polymerizable groups, and both are preferably photopolymerizable groups. The photopolymerizable group means a group that can participate in a polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later.

The photopolymerizable group represented by U ¹ and the polymerizable group represented by U ² may be different from each other, but are preferably the same type of group. Examples of the polymerizable group include a vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, and oxetanyl group. Among these, a radical polymerizable group is preferable, an acryloyloxy group, a methacryloyloxy group, a vinyl group, and a vinyloxy group are more preferable, an acryloyloxy group and a methacryloyloxy group are more preferable, and an acryloyloxy group is still more preferable.

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- 1,5-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 Groups and icosane-1,20-diyl groups. V ¹ and V ² are preferably alkanediyl groups having 2 to 12 carbon atoms, and more preferably alkanediyl groups having 6 to 12 carbon atoms.

  Examples of the substituent that the alkanediyl group optionally has include a cyano group and a halogen atom. The alkanediyl group is preferably unsubstituted, and is an unsubstituted and linear alkanediyl group. Is more preferable.

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

  Examples of the polymerizable liquid crystal compound (B1) include compounds represented by formulas (B-1) to (B-25). When the polymerizable liquid crystal compound (B1) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans isomer.

  Among these, Formula (B-2), Formula (B-3), Formula (B-4), Formula (B-5), Formula (B-6), Formula (B-7), Formula (B- 8) at least one selected from the group consisting of compounds represented by formula (B-13), formula (B-14), formula (B-15), formula (B-16) and formula (B-17) Species are preferred.

  The exemplified polymerizable liquid crystal compounds can be used alone or in combination. When combining two or more kinds of polymerizable liquid crystal compounds, at least one kind is preferably a polymerizable liquid crystal compound, and more preferably two or more kinds are polymerizable liquid crystal compounds. In combination, the liquid crystallinity may be temporarily maintained even at a temperature lower than the liquid crystal-crystal phase transition temperature. When mixing two kinds of polymerizable liquid crystal compounds, the mixing ratio is usually 1:99 to 50:50, preferably 5:95 to 50:50, more preferably 10:90 to 50:50. It is.

  Polymerizable liquid crystal compounds are available from Lub et al. Recl. Trav. Chim. It is manufactured by a known method described in Pays-Bas, 115, 321-328 (1996), Japanese Patent No. 4719156, and the like.

  The content of the polymerizable liquid crystal compound in the solid content of the composition for forming a polarizing film is preferably 50% by mass or more, more preferably 70% by mass or more, preferably 99% by mass or less, more preferably 95% by mass or less. More preferably, it is 90 mass% or less. In this specification, solid content in the composition for polarizing film formation means the total amount of the component remove | excluding volatile components, such as a solvent, from the composition for polarizing film formation.

[Dichroic dye]
The composition for forming a polarizing film of the present invention contains a dichroic dye. The dichroic dye means a dye having a property that the absorbance in the major axis direction of the molecule is different from the absorbance in the minor axis direction. The dichroic dye is not limited as long as it has such properties, and may be a dye or a pigment. Two or more dyes may be used in combination, two or more pigments may be used in combination, or a dye and a pigment may be used in combination.

The composition for forming a polarizing film preferably contains a dichroic dye having a maximum absorption wavelength (λ _MAX ) in the wavelength range of 300 to 700 nm, and has maximum absorption in the wavelength range of 300 to 550 nm, particularly absorption near 380 nm. It is more preferable to include a dichroic dye having (sometimes referred to as a dichroic dye (1)). The method for adjusting to the range of the formula (1) is not limited, but particularly the amount of the dichroic dye having such absorption is set so that the absorbance at 380 nm of the composition for forming a polarizing film is 1.2 or more. By adjusting to, the relationship of the formula (1) can be satisfied.

The composition for forming a polarizing film comprises a dichroic dye having a maximum absorption wavelength (λ _MAX ) in the wavelength range of 550 to 700 nm, particularly an absorption wavelength in the vicinity of 650 nm (sometimes referred to as dichroic dye (2)). More preferably. The method for adjusting to the range of the formula (2) is not limited, but particularly the amount of the dichroic dye having such absorption is set so that the absorbance at 650 nm of the composition for forming a polarizing film is 0.8 or less. By adjusting to, the relationship of the formula (2) can be satisfied. The absorbance of the dichroic dye represents the absorbance of a solution diluted with an organic solvent such as chloroform so that the concentration of the dichroic dye is 0.02% by mass. For example, the method described in Examples Can be measured.

  The polarizing film-forming composition of the present invention preferably contains at least a dichroic dye (1) as a dichroic dye, and more preferably further contains a dichroic dye (2). The dichroic dye (1) and the dichroic dye (2) can be used alone or in combination of two or more.

  Examples of the dichroic dye contained in the composition for forming a polarizing film include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, and an anthraquinone dye, and among them, an azo dye is preferable. Examples of the azo dye include a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, and a stilbene azo dye, and a bisazo dye and a trisazo dye are preferable.

Examples of the azo dye include a compound represented by the formula (I) (hereinafter sometimes referred to as “compound (I)”).
_{^{K 1 (-N = N-K}} 2) p -N = N-K 3 (I)
[In Formula (I), K ¹ and K ³ may each independently have a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a substituent. Represents a good monovalent heterocyclic group. K ² represents a p-phenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocyclic ring which may have a substituent. Represents a group. p represents an integer of 1 to 4. When p is an integer greater than or equal to ² , several K2 may mutually be same or different. The —N═N— bond may be replaced by a —C═C—, —COO—, —NHCO—, or —N═CH— bond within the visible absorption range. ]

  Examples of the monovalent heterocyclic group include groups in which one hydrogen atom has been removed from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include groups in which two hydrogen atoms have been removed from the heterocyclic compound.

As a substituent that 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 optionally have Is an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group or a butoxy group; a fluorinated alkyl group having 1 to 4 carbon atoms such as a trifluoromethyl group; a cyano group; Nitro group; halogen atom; substituted or unsubstituted amino group such as amino group, diethylamino group, pyrrolidino group (substituted amino group is an amino group having one or two alkyl groups having 1 to 6 carbon atoms, or two This means an amino group in which substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms, and the unsubstituted amino group is —NH ₂ .

［式（Ｉ−１）〜（Ｉ−８）中、
Ｂ^１〜Ｂ^３０は、互いに独立に、水素原子、炭素数１〜６のアルキル基、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Ｂ¹⁴は互いに同一でも異なっていてもよい。］ Among the compounds (I), a compound represented by any one of formulas (I-1) to (I-8) is preferable, and represented by any one of formulas (I-1) to (I-3). The compound represented by formula (I-1) and formula (I-3) is more preferred.

[In the 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 alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (a substituted amino group and The definition of an unsubstituted amino group is as described above, and represents a chlorine atom or a trifluoromethyl group.
n1 to n4 each independently represents an integer of 0 to 3.
when n1 is 2 or more, the plurality of B ² may be the same as or different from each other;
when n2 is 2 or more, the plurality of B ⁶ may be the same as or different from each other;
when n3 is 2 or more, the plurality of B ⁹ may be the same as or different from each other;
When n4 is 2 or more, the plurality of B ¹⁴ may be the same as or different from each other. ]

［式（Ｉ−９）中、
Ｒ^１〜Ｒ^８は、互いに独立に、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。］ As the anthraquinone dye, a compound represented by the formula (I-9) is preferable.

[In the 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−１０）中、
Ｒ^９〜Ｒ^１５は、互いに独立に、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 the formula (I-10).

[In the formula (I-10),
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、互いに独立に、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が挙げられる。 The acridine dye is preferably a compound represented by the formula (I-11).

[In the formula (I-11),
R ¹⁶ to R ^23, independently of each other, represent a hydrogen _{^{atom, -R x, -NH 2, -NHR}} x, -NR x 2, the -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 of R ^x is a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group. And an aryl group having 6 to 12 carbon atoms include a phenyl group, a toluyl group, a xylyl group, and a 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（Ｉ−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。］ As the cyanine dye, a compound represented by the formula (I-12) and a compound represented by the formula (I-13) are preferable.

[In the 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 of 1 to 3. ]

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

n6 represents an integer of 1 to 3. ]

  Among these dichroic dyes, azo dyes are preferable from the viewpoint of orientation.

Specific examples of the dichroic dye (1) having a maximum absorption wavelength (λ _MAX ) in the wavelength range of 300 to 550 nm include compounds described in JP-A No. 2006-006502.

Specific examples of the dichroic dye (2) having a maximum absorption wavelength (λ _MAX ) in the wavelength range of 550 to 700 nm include compounds described in JP2013-227532A.

  The content of the dichroic dye (1) in the solid content of the composition for forming a polarizing film is preferably 1.3% by mass or more, more preferably 1.5% by mass or more, and further preferably 1.8% by mass or more. Even more preferably, it is 2.0% by mass or more, particularly preferably 3.0% by mass or more, and most preferably 3.5% by mass or more. Although depending on the type of the dichroic dye (1), when the content of the dichroic dye (1) is not less than the above value, a polarizing film-forming composition satisfying the above formula (1) can be easily obtained. Therefore, long-term storage stability of the composition for forming a polarizing film is improved, and the occurrence of alignment defects in the resulting polarizing film can be more easily suppressed. The content value of the dichroic dye (1) is preferably 20% by mass or less, more preferably 10% by mass or less.

  The content of the dichroic dye (2) in the solid content of the composition for forming a polarizing film is preferably 3.8% by mass or less, more preferably 3.5% by mass or less, and further preferably 3.0% by mass or less. Especially preferably, it is 2.5 mass% or less. Although it depends on the type of the dichroic dye (2), when the content of the dichroic dye (2) is not more than the above value, a composition for forming a polarizing film satisfying the formula (2) is easily obtained. For this reason, it becomes easy to visually observe foreign matters and the like in the composition. The content value of the dichroic dye (2) is preferably 0.1% by mass or more, more preferably 1% by mass or more.

  When the composition for forming a polarizing film of the present invention contains at least a dichroic dye (1) and a dichroic dye (2), the visibility of foreign matters in the composition and the good orientation of the obtained polarizing film The content of the dichroic dye (2) is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 0.1 parts by mass with respect to 1 part by mass of the dichroic dye (1). 3 mass parts may be sufficient, Preferably it is 0.05-3 mass parts, More preferably, it is 0.1-1 mass part, More preferably, 0.2-0.8 mass part may be sufficient.

  The content (total content) of the dichroic dye in the solid content of the composition for forming a polarizing film is preferably 1% by mass or more, more preferably 3% by mass or more, and further preferably 5% by mass or more. Is 60% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less. If the content (total content) of the dichroic dye is equal to or more than the above value, the long-term storage stability of the composition for forming a polarizing film and the polarization obtained can be obtained, depending on the type of dichroic dye contained. It is easy to develop good orientation and polarization performance of the film. When the content (total content) of the dichroic dye is equal to or less than the above value, although depending on the type of the dichroic dye contained, good visibility such as foreign matter in the polarizing film forming composition is obtained. It is easy to express.

[Organic solvent]
The composition for forming a polarizing film of the present invention contains an organic solvent. As the organic solvent, those capable of dissolving the polymerizable liquid crystal compound and the dichroic dye can be appropriately selected according to these types. In general, a smectic liquid crystal compound has a high viscosity. Therefore, when the polymerizable liquid crystal composition contains an organic solvent, application is easy, and as a result, it is often easy to form a polarizing film. Specific examples of organic solvents include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone Ester solvents such as propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; toluene , Aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile; solvents such as tetrahydrofuran and dimethoxyethane Le solvent; and chloroform, and chlorinated hydrocarbon solvents such as chlorobenzene and the like. An organic solvent can be used individually or in combination of 2 or more types. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and still more preferably 180 to 600 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal composition.

[Photopolymerization initiator]
The composition for forming a polarizing film of the present invention contains a photopolymerization initiator. As the photopolymerization initiator, a photopolymerization initiator having light absorption at a wavelength of 300 nm to 380 nm is usually used. The photopolymerization initiator is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound, and can initiate the polymerization reaction at a lower temperature. Specific examples include photopolymerization initiators that can generate active radicals or acids by the action of absorbed light. Among these, photopolymerization initiators that generate radicals by the action of light are preferred.

  Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts. These photoinitiators can be used individually or in combination of 2 or more types.

  Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

  Examples of the benzophenone compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3 ′, 4,4′-tetra (tert-butylperoxycarbonyl) benzophenone. And 2,4,6-trimethylbenzophenone.

  Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one, 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane. -1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1- [ 4- (2-hydroxyethoxy) phenyl] propan-1-one, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propan-1-one An oligomer is mentioned.

  Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide.

  As triazine compounds, 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 (trichloro Methyl) -6- [2 -(3,4-Dimethoxyphenyl) ethenyl] -1,3,5-triazine.

  A commercially available photopolymerization initiator can be used. Commercially available polymerization initiators include “Irgacure (registered trademark) 907”, “Irgacure (registered trademark) 184”, “Irgacure (registered trademark) 651”, “Irgacure (registered trademark) 819”, “Irgacure (registered trademark)” "Registered Trademark) 250", "Irgacure (Registered Trademark) 369" (Ciba Japan Co., Ltd.); "Sequol (Registered Trademark) BZ", "Sequol (Registered Trademark) Z", "Sequeall (Registered Trademark) BEE" ( Seika Chemical Co., Ltd.); “Kayacure (registered trademark) BP100” (Nippon Kayaku Co., Ltd.); “Kayacure (registered trademark) UVI-6992” (manufactured by Dow); “Adekaoptomer SP-152 "Adekaoptomer SP-170" (ADEKA); "TAZ-A", "TAZ-PP" Siber Hegner Ltd.); and "TAZ-104" (Sanwa Chemical Co., Ltd.).

  The photopolymerization initiator absorbs light, for example, ultraviolet light including a wavelength of 300 to 380 nm, and thereby generates a radical or an acid, so that the polymerization reaction of the polymerizable liquid crystal compound in the composition proceeds by the generated radical or the like. It will be polymerized. However, in the composition for forming a polarizing film of the present invention, the absorbance at a wavelength of 380 nm is preferably adjusted to 1.2 or more by a dichroic dye (particularly the dichroic dye (1)). Even if light is exposed to the composition, the composition itself, particularly the dichroic dye (particularly the dichroic dye (1)) contained in the composition absorbs the exposure light, and the radical of the photopolymerization initiator, etc. Generation and polymerization of the polymerizable liquid crystal compound due to the radicals can be effectively suppressed or prevented. Therefore, the composition for forming a polarizing film of the present invention causes little or no alignment defect even when the polymerizable liquid crystal compound in the composition is polymerized in an aligned state. Therefore, the composition for forming a polarizing film of the present invention is stable for a long period of time even if it contains a photopolymerization initiator, preferably a photopolymerization initiator having light absorption at a wavelength of 300 to 380 nm, which is advantageous in terms of orientation polymerizability. And a polarizing film having excellent orientation even after long-term storage can be obtained.

  The content of the photopolymerization initiator can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound contained in the polarizing film forming composition, but is preferably relative to 100 parts by mass of the polymerizable liquid crystal compound. 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, further preferably 1 part by mass or more, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less. is there. It can superpose | polymerize, without disturbing the orientation of a polymeric liquid crystal compound as content of a photoinitiator is more than said lower limit. Moreover, long-term storage stability can be improved as content of a photoinitiator is below said upper limit, and it is easy to suppress or prevent generation | occurrence | production of the orientation defect of the polarizing film obtained.

[Other additives]
The composition for forming a polarizing film of the present invention may contain one or more leveling agents. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing film and making the coating film obtained by coating the composition more flat, and specifically includes a surfactant. . As a leveling agent, at least 1 sort (s) chosen from the group which consists of a leveling agent which has a polyacrylate compound as a main component, and a leveling agent which has a fluorine atom containing compound as a main component is preferable.

  Leveling agents mainly composed of polyacrylate compounds include “BYK-350”, “BYK-352”, “BYK-353”, “BYK-354”, “BYK-355”, “BYK-358N”, “ BYK-361N ”,“ BYK-380 ”,“ BYK-381 ”, and“ BYK-392 ”[BYK Chemie].

  Leveling agents mainly composed of fluorine atom-containing compounds include “Megafac (registered trademark) R-08”, “R-30”, “R-90”, “F-410”, and “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 Laboratory, Inc.]; F-top EF301 "," F-top EF303 "," F-top EF35 "And" F-top EF352 "[Mitsubishi Materials electronic Kasei Co., Ltd.] and the like.

  When the composition for forming a polarizing film 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 with respect to 100 parts by mass of the polymerizable liquid crystal compound. . If the content of the leveling agent is within the above range, the resulting polarizing film tends to be smoother and unevenness tends not to occur.

  The composition for forming a polarizing film of the present invention may further contain a photosensitizer. Photosensitizers include xanthone compounds such as xanthone and thioxanthone (2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene compounds such as anthracene and alkoxy group-containing anthracene (such as dibutoxyanthracene); phenothiazine and rubrene Can be mentioned. A photosensitizer can be used individually or in combination of 2 or more types.

  When the composition for forming a polarizing film contains a photosensitizer, the polymerization reaction of the polymerizable liquid phase compound contained in the composition can be further accelerated. Although the usage-amount of a photosensitizer can be suitably adjusted according to the kind and amount of a photoinitiator and a polymeric liquid crystal compound, 0.1-30 mass parts is with respect to 100 mass parts of polymeric liquid crystal compounds. Preferably, 0.5-10 mass parts is more preferable, and 0.5-8 mass parts is further more preferable.

  In order to allow the polymerization reaction of the composition for forming a polarizing film to proceed more stably, the composition may contain an appropriate amount of a polymerization inhibitor, thereby increasing the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound. It becomes easier to control.

  As polymerization inhibitors, radical scavengers such as hydroquinone, alkoxy group-containing hydroquinone, alkoxy group-containing catechol (eg, butyl catechol), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxy radical, etc. Thiophenols; β-naphthylamines and β-naphthols.

  When the composition for forming a polarizing film contains a polymerization inhibitor, the content can be adjusted as appropriate according to the type and amount of the polymerizable liquid crystal compound and the amount of the photosensitizer used. 0.1-30 mass parts is preferable with respect to 100 mass parts of compounds, 0.5-10 mass parts is more preferable, and 0.5-8 mass parts is more preferable. When the content of the polymerization inhibitor is within this range, the polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal compound.

  The composition for forming a polarizing film may contain an additive other than a leveling agent, a photosensitizer, and a polymerization inhibitor. Other additives include colorants such as antioxidants, mold release agents, stabilizers, bluing agents, flame retardants and lubricants. When the composition for forming a polarizing film contains another additive, the content of the other additive is more than 0% and 20% by mass or less with respect to the mass of the solid content of the polymerizable liquid crystal composition. More preferably, it is more than 0% and 10% by mass or less.

  The solid content in the composition for forming a polarizing film is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and still more preferably 20 to 40% based on the mass of the composition for forming a polarizing film. % By mass.

  The composition for forming a polarizing film is usually prepared by, for example, stirring and mixing the polymerizable liquid crystal compound, the dichroic dye, the photopolymerization initiator, the organic solvent, and, if necessary, the above additives. Can be prepared.

<Polarizing film>
The present invention includes a polarizing film that is a cured product of the composition for forming a polarizing film. The polarizing film of the present invention is a film (film) having a polarizing function, and a dichroic dye is included in a polymerizable liquid crystal in an aligned state. Since the polarizing film of the present invention is formed from the composition for forming a polarizing film, it has little or no alignment defect and has excellent polarizing performance.

The polarizing film of the present invention includes, for example, a step (ii) of forming a coating film of the composition for forming a polarizing film and drying and removing an organic solvent from the coating film, and a polymerizable liquid crystal compound in a state of a smectic liquid crystal phase. It can be produced by a method including the step (iii) of orientation hardening.

  In step (ii), the polarizing film-forming composition is applied on a substrate, alignment film, or other layer (for example, a functional layer) described later to form a coating film, and is included in the obtained coating film. In this process, the organic solvent is removed by drying under conditions where the polymerizable liquid crystal compound is not polymerized to obtain a dry film. The polarizing film may be applied directly on the substrate or another layer (for example, a functional layer), but it is preferable to apply the polarizing film on an alignment film having alignment regularity.

  In the step (ii), examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method, and a vacuum drying method. When the polymerizable liquid crystal compound is a polymerizable smectic liquid crystal compound, the liquid crystal state of the polymerizable smectic liquid crystal compound contained in the dry film is preferably changed to a nematic phase (nematic liquid crystal state), and then transferred to the smectic phase. In order to form a smectic phase via a nematic phase, for example, the dry film is heated to a temperature above the temperature at which the polymerizable smectic liquid crystal compound contained in the dry film transitions to the liquid crystal state of the nematic phase, and then the polymerizable smectic. A method in which the liquid crystal compound is cooled to a temperature at which the liquid crystal state of the smectic phase is exhibited is employed.

  Step (iii) is a step of aligning and curing the polymerizable liquid crystal compound in the dry film in the state of a smectic liquid crystal phase. Hereinafter, a method for photopolymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the smectic phase after the liquid crystal state of the polymerizable liquid crystal compound in the dry film in the step (ii) is changed to a smectic phase will be described. In the photopolymerization, the light applied to the dry film includes the type of photopolymerization initiator contained in the dry film, the type of polymerizable liquid crystal compound (particularly, the type of photopolymerizable group possessed by the polymerizable liquid crystal compound), and its As appropriate examples, one or more kinds of light and active electrons selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays are used. A line is mentioned. Among these, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction and that a wide variety of photopolymerization apparatuses can be used in this field, and the polymerization is performed so that photopolymerization can be performed by ultraviolet light. It is preferable to select the type of polymerizable liquid crystal compound and photopolymerization initiator contained in the liquid crystal composition. Further, at the time of polymerization, the polymerization temperature can be controlled by irradiating with light while cooling the dry film by an appropriate cooling means. By adopting such a cooling means, if a polymerizable liquid crystal compound is polymerized at a lower temperature, a polarizing film can be appropriately formed even if a substrate having a relatively low heat resistance is used. During the photopolymerization, a patterned polarizing film can be obtained by masking or developing.

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

The ultraviolet irradiation intensity is usually 10 to 3,000 mW / cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the photopolymerization initiator. The time for irradiating light is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and further preferably 10 seconds to 1 minute. When irradiating once or a plurality of times with such ultraviolet irradiation intensity, the integrated light quantity is 10 to 3,000 mJ / cm ² , preferably 50 to 2,000 mJ / cm ² , more preferably 100 to 1,000 mJ / cm ² . ² .

  By performing photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining the liquid crystal state of a smectic phase, preferably a higher order smectic phase, and a polarizing film is formed. A polarizing film obtained by polymerizing a polymerizable liquid crystal compound while maintaining the liquid crystal state of the smectic phase is accompanied by the action of the dichroic dye, and the conventional host guest type polarizing film, that is, from the liquid crystal state of the nematic phase. As compared with the polarizing film, there is an advantage that the polarization performance is high. Furthermore, there is an advantage that it is excellent in strength as compared with a case where only a dichroic dye or a lyotropic liquid crystal is applied.

  The thickness of the polarizing film can be appropriately selected depending on the display device to be applied, and is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and still more preferably 0.5 to 3 μm.

  Since the composition for forming a polarizing film of the present invention is excellent in long-term storage stability, it can be used after long-term storage. Therefore, in the step (ii), a composition for forming a polarizing film after storage may be used. When using the composition for forming a polarizing film after storage, it is preferable to further perform step (i) from the viewpoint of effectively suppressing or preventing orientation defects of the polarizing film to be obtained.

  Step (i) is a step of storing the composition for forming a polarizing film in a state satisfying Formula (1) and / or Formula (2).

  In the step (i), the storage temperature is preferably 15 to 35 ° C, more preferably 20 to 30 ° C. If it is such a temperature, it is easy to store in a state satisfying the above-mentioned formulas (1) and (2).

  The composition for forming a polarizing film is usually stored in a sealed state so that the organic solvent does not evaporate. Although the container containing the composition for forming a polarizing film can be shielded, the composition for forming a polarizing film of the present invention is particularly a radical in which the dichroic dye in the composition is derived from a photopolymerization initiator. Can absorb ultraviolet light (wavelength of 380 nm) that can generate odor, and thus is excellent in long-term storage stability without being shielded.

<Polarizing plate>
The present invention includes a polarizing plate including a polarizing film, a substrate, and an alignment film. Since the polarizing plate of the present invention includes the polarizing film, it has little or no alignment defect and has excellent polarizing performance.

  In the polarizing plate of the present invention, the order of the polarizing film, the base material, and the alignment film is not particularly limited, but from the viewpoint of imparting alignment regularity to the polarizing film in the manufacturing process, the base material, the alignment film, and the polarizing film are in this order. Has been placed.

[Base material]
The substrate is usually a transparent substrate. The polarizing plate including the polarizing film of the present invention is a base material when the base material is not placed on the display surface of the display element, for example, when the laminate obtained by removing the base material from the polarizing plate is placed on the display surface of the display element. May not be transparent. The transparent substrate means a substrate having transparency capable of transmitting light, particularly visible light, and the transparency is a characteristic that the transmittance with respect to a light beam having a wavelength of 380 to 780 nm is 80% or more. Say. Specific examples of the transparent substrate include a translucent resin substrate. Examples of the resin constituting the translucent resin base material include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate esters; polyacrylate esters; Examples thereof include cellulose esters such as diacetylcellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene oxide. From the viewpoint of easy availability and transparency, polyethylene terephthalate, polymethacrylic acid ester, cellulose ester, cyclic olefin resin or polycarbonate is preferred. Cellulose ester is obtained by esterifying a part or all of hydroxyl groups contained in cellulose and can be easily obtained from the market. Cellulose ester base materials can also be easily obtained from the market. Commercially available cellulose ester base materials include “Fujitac Film” (Fuji Photo Film Co., Ltd.); “KC8UX2M”, “KC8UY” and “KC4UY” (Konica Minolta Opto Co., Ltd.).

  Although the characteristics required for the substrate vary depending on the configuration of the polarizing plate, a substrate having as small a retardation as possible is usually preferable. Examples of the substrate having as little retardation as possible include cellulose ester films having no phase difference such as zero tack (Konica Minolta Opto Co., Ltd.), Z tack (Fuji Film Co., Ltd.) and the like. An unstretched cyclic olefin resin substrate is also preferred.

  For example, in the case of a polarizing plate in which a polarizing film is laminated with or without an alignment film on the base material, a hard coat treatment, an antireflection treatment, an antistatic treatment is performed on the surface of the base material on which the polarizing film is not laminated. Etc. may be made. In addition, the hard coat layer may contain additives such as an ultraviolet absorber as long as the performance is not affected.

  If the thickness of the substrate is too thin, the strength tends to decrease and the workability tends to be inferior, so it is usually 5 to 300 μm, preferably 20 to 200 μm, more preferably 20 to 100 μm.

[Alignment film]
The polarizing film is preferably formed on the alignment film. The alignment film has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction. As an alignment film, it has solvent resistance that does not dissolve due to application of a composition for forming a polarizing film containing a polymerizable liquid crystal compound, and also has heat resistance in heat treatment for removal of the solvent and alignment of the polymerizable liquid crystal compound. Those having the following are preferred. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, a groove alignment film having a concavo-convex pattern and a plurality of grooves on the surface, and a stretched film stretched in the alignment direction.

  Examples of the alignment polymer include polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule and polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, Examples include polyethyleneimine, polystyrene, polyvinyl pyrrolidone, polyacrylic acid and polyacrylic ester. Among these, polyvinyl alcohol is preferable. The orientation polymers can be used alone or in combination of two or more.

  The alignment film containing the alignment polymer is usually applied to a substrate with a composition in which the alignment polymer is dissolved in a solvent (hereinafter, sometimes referred to as an alignment polymer composition), and the solvent is removed. It is obtained by applying the polymer composition to a substrate, removing the solvent, and rubbing (rubbing method). Examples of the solvent include the same solvents as those described in the above [Organic solvent] section.

  The concentration of the orienting polymer in the orienting polymer composition may be within the range where the orienting polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20% in terms of solid content with respect to the solution, About 1 to 10% is more preferable.

  A commercially available alignment film material may be used as it is as the alignment polymer composition. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optmer (registered trademark, manufactured by JSR).

  Examples of methods for applying the orientation polymer composition to the substrate include spin coating methods, extrusion methods, gravure coating methods, die coating methods, bar coating methods, applicator methods, and other flexographic methods. There are known methods.

  Examples of the method for removing the solvent contained in the oriented polymer composition include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

  In order to impart alignment regulating force to the alignment film, rubbing treatment can be performed as necessary (rubbing method).

  As a method for imparting alignment regulating force by the rubbing method, a rubbing cloth was wound, and the orientation polymer composition was applied to the rotating rubbing roll and annealed and formed on the substrate surface. The method of making the film | membrane of an orientation polymer contact is mentioned.

  The photo-alignment film is usually obtained by applying a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter sometimes referred to as “photo-alignment film-forming composition”) to a substrate, and polarizing ( Preferably, it is obtained by irradiation with polarized UV). The photo-alignment film is more preferable in that the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized light to be irradiated.

  The photoreactive group refers to a group that generates liquid crystal alignment ability when irradiated with light. Specific examples include groups involved in photoreactions that are the origin of liquid crystal alignment ability such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction or photodecomposition reaction caused by light irradiation. Among them, a group involved in the dimerization reaction or the photocrosslinking reaction is preferable in terms of excellent orientation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable. A group having at least one selected from the group consisting of a heavy bond (N═N bond) and a carbon-oxygen double bond (C═O bond) is particularly preferred.

  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 a structure 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, and a halogenated alkyl group.

  Among them, a photoreactive group involved in the photodimerization reaction is preferable, the amount of polarized light irradiation necessary for photoalignment is relatively small, and a photoalignment film excellent in thermal stability and temporal stability can be easily obtained. A cinnamoyl group and a chalcone group are preferred. As the polymer having a photoreactive group, a polymer having a cinnamoyl group in which the terminal portion of the polymer side chain has a cinnamic acid structure is particularly preferable.

  By applying the composition for forming a photo-alignment film on the substrate, the photo-alignment inducing layer can be formed on the substrate. Examples of the solvent contained in the composition include the same solvents as those described in the section “Organic solvent”, and can be appropriately selected depending on the solubility of the polymer or monomer having a photoreactive group.

  The content of the polymer or monomer having a photoreactive group in the composition for forming a photoalignment film can be appropriately adjusted depending on the type of the polymer or monomer and the thickness of the target photoalignment film. The mass is preferably at least 0.2 mass%, more preferably in the range of 0.3-10 mass%. As long as the properties of the photo-alignment film are not significantly impaired, the composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer.

  Examples of the method for applying the composition for forming a photo-alignment film to a substrate include the same methods as those for applying the alignment composition to a substrate. Examples of the method for removing the solvent from the applied composition for forming a photo-alignment film include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

  In order to irradiate polarized light, even in a form in which the solvent is removed from the composition for forming a photo-alignment film applied on the substrate and the polarized UV is directly irradiated, the polarized light is irradiated from the substrate side to transmit the polarized light. It may be in the form of irradiation 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 region where the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) having a wavelength in the range of 250 to 400 nm is particularly preferable. Examples of the light source used for the polarized light irradiation include xenon lamps, high pressure mercury lamps, ultra high pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and the like. High pressure mercury lamps, ultra high pressure mercury lamps and metal halides A lamp is more preferred. Among these, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and a metal halide lamp are preferable because of high emission intensity of ultraviolet rays having a wavelength of 313 nm. By irradiating light from the light source through an appropriate polarizer, polarized UV light can be irradiated. As such a polarizer, a polarizing prism such as a polarizing filter, Glan-Thompson, or Granteller, or a wire grid type polarizer can be used.

  Note that a plurality of regions (patterns) having different liquid crystal alignment directions can be formed by performing masking during rubbing or polarized light irradiation.

  The groove alignment film is a film having a concavo-convex pattern or a plurality of grooves (grooves) on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, liquid crystal molecules are aligned in a direction along the groove.

  As a method for obtaining a groove alignment film, a method of forming a concavo-convex pattern by performing development and rinsing after exposure through an exposure mask having a pattern-shaped slit on the photosensitive polyimide film surface, a plate having grooves on the surface A layer of a pre-curing UV curable resin is formed on the substrate, and a method of curing the resin layer after transferring the formed resin layer to the base material, and a pre-curing UV curable resin film formed on the base material, Examples include a method in which a roll-shaped master having a plurality of grooves is pressed to form irregularities and then cured.

  The thickness of the alignment film (alignment film or alignment film containing an alignment polymer) is usually in the range of 10 to 10000 nm, preferably in the range of 10 to 1000 nm, more preferably 500 nm or less, still more preferably. The range is 10 to 200 nm, particularly preferably 50 to 150 nm.

  The polarizing plate of the present invention, for example, a preferred polarizing plate having a substrate, an alignment film and a polarizing film in this order, is formed on the alignment film as described above, and then on the alignment film, the step (ii) and the step A polarizing film can be formed and produced by a method including (iii) or step (i) to step (iii).

  The polarizing plate of this invention may contain other layers other than a base material, an alignment film, and a polarizing film. Examples of the other layer include a functional layer, and examples of the functional layer include layers having functions such as a polarizing layer other than the polarizing film, a retardation layer, an ultraviolet absorbing layer, an adhesive layer, a hue adjusting layer, and a refractive index adjusting layer. It can be illustrated. The polarizing plate may include one or more functional layers. One functional layer may have a plurality of functions.

  Since the polarizing plate of the present invention is excellent in polarization performance, it can be applied to a display device or the like. A display device is a device having a display mechanism and includes a light-emitting element or a light-emitting device as a light-emitting source. Display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FED, etc.), surface field emission display devices. (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection display device (grating light valve (GLV) display device, display device having digital micromirror device (DMD)) Etc.) and a piezoelectric ceramic display, and an organic EL display device and a touch panel display device are particularly preferable, and an organic EL display device is particularly preferable. In addition, the display apparatus containing the polarizing plate of this invention can be obtained by bonding the polarizing plate of this invention to the surface of a display apparatus through an adhesive or an adhesive agent.

  The present invention will be described more specifically based on examples. However, the present invention is not limited to these examples. Unless otherwise specified, “%” and “parts” in Examples and Comparative Examples are “% by mass” and “parts by mass”.

[Example 1]
[Production of Composition for Forming Polarizing Film]
The following components were mixed at the following ratio, and the resulting mixture was stirred at 80 ° C. for 1 hour to obtain a polarizing film forming composition. As the dichroic dye, the following azo dye synthesized in the same manner as the compound described in JP2013-101328A was used.

・式（１−７）で表される重合性液晶化合物 ２５部

(Polymerizable liquid crystal compound)
75 parts of polymerizable liquid crystal compound represented by formula (1-6)

25 parts of polymerizable liquid crystal compound represented by formula (1-7)

・下記に示す二色性色素（２）（５９０ｎｍに極大吸収波長を有する） ２．２部

・下記に示す二色性色素（１−２）（４９０ｎｍに極大吸収波長を有する） ２．６部

(Dichroic dye)
-Dichroic dye (1-1) shown below (having a maximum absorption wavelength at 380 nm) 2.6 parts

The following dichroic dye (2) (having a maximum absorption wavelength at 590 nm) 2.2 parts

-Dichroic dye (1-2) shown below (having a maximum absorption wavelength at 490 nm) 2.6 parts

(Other ingredients)
A polymerization initiator;
2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals) 6 parts Leveling agent;
Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)
1.2 parts solvent;
o-Xylene 250 parts

(Measurement of absorbance)
The polarizing film-forming composition obtained above was diluted with o-xylene (ortho-xylene) so that the concentration was 0.4% by mass, and the absorbance at 380 nm of the resulting solution (A (380) ) And the absorbance at 650 nm (A (650)) were diluted with a spectrophotometer [product name “V7100” manufactured by JASCO Corporation] with the diluted polarizing film forming composition so that the optical path length was 1 cm. Measurements were made in a cell. The measurement results are shown in Table 1. In addition, the said density | concentration shows the mass of the composition for polarizing film formation with respect to the total mass (100 mass%) of the composition for polarizing film formation, and o-xylene for dilution.

(Measurement of maximum absorption wavelength of dye)
The dichroic dyes (1-1), (2), and (1-2) were diluted with chloroform so that the concentration of the dichroic dye was 0.02% by mass, and the absorbance of the resulting solution was spectroscopically analyzed. The diluted solution was placed in a quartz cell with a photometer (product name “V7100” manufactured by JASCO Corporation) so that the optical path length was 1 cm, and the measurement was performed.

[Standing test]
The polarizing layer forming composition obtained above is put in a sample bottle and stored at room temperature (20 to 30 ° C.) for one month, and after one month, the sample bottle is shaken to obtain the polarizing layer forming composition. The liquid state was visually confirmed and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
○: not much different from initial (one month ago) Δ: Increased viscosity was confirmed ×: Gelation was confirmed

[Visual test]
After adding 0.1% by mass of silica gel as a foreign substance to the polarizing layer forming composition obtained above, it was filled in a capillary having an inner diameter of 0.04 mm and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
○… Silica gel can be easily seen. ×… It is difficult to see.

[Confirmation of orientation defects]
A triacetylcellulose film (Konica Minolta, “KC4UY-TAC”, thickness 40 μm) as a substrate is cut into 20 × 20 mm, and corona treatment (“AGF-B10”, Kasuga Denki Co., Ltd.) is applied to the surface. did. After applying the composition for forming a photo-alignment film on the surface of the base material (film) that has been subjected to the corona treatment, it is dried in a drying oven set at 120 ° C. for 1 minute, and applied for photo-alignment film A layer was obtained. Using a polarized UV irradiation device (“SPOT CURE SP-7” manufactured by USHIO INC.) On the coating layer for the photo-alignment film, polarized UV in the direction of 0 ° with respect to the film side is 50 mJ / cm ² ( An alignment film (thickness: 90 nm) was formed by irradiation with an integrated light amount of 313 nm. On the obtained alignment film, after applying the polarizing film forming composition used in the static test (after the static test) using a bar coater, the coating film was dried in a drying oven set at 110 ° C. for 1 minute. Dried. Then, using a high-pressure mercury lamp ("UNICURE VB-15201BY-A", manufactured by USHIO INC.), Irradiation with ultraviolet rays (in a nitrogen atmosphere, wavelength: 365 nm, integrated light quantity at wavelength 365 nm: 1000 mJ / cm ² ) Then, a polarizing film (thickness 1.6 μm) in which the polymerizable liquid crystal compound and the dichroic dye were aligned was obtained. The obtained polarizing film was observed at a magnification of 400 times using a polarizing microscope (“BX51”, manufactured by Olympus Corporation), and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
○: Orientation defects were observed on the surface of the polarizing film. Δ: Orientation defects were slightly observed on the surface of the polarizing film.

[Example 2]
Except for changing the dichroic dye (1-1) to 3.7 parts, the dichroic dye (2) to 3.4 parts, and the dichroic dye (1-2) to 3.7 parts, In the same manner as in Example 1, a polarizing film forming composition and a polarizing film were produced. Each evaluation result is shown in Table 1.

Example 3
Except for changing the dichroic dye (1-1) to 2.1 parts, the dichroic dye (2) to 1.8 parts, and the dichroic dye (1-2) to 2.1 parts, In the same manner as in Example 1, a polarizing film forming composition and a polarizing film were produced. Each evaluation result is shown in Table 1.

Example 4
Except for changing the dichroic dye (1-1) to 1.8 parts, the dichroic dye (2) to 1.6 parts, and the dichroic dye (1-2) to 1.8 parts, In the same manner as in Example 1, a polarizing film forming composition and a polarizing film were produced. Each evaluation result is shown in Table 1.

Example 5
Except for changing dichroic dye (1-1) to 4.8 parts, dichroic dye (2) to 4.5 parts, and dichroic dye (1-2) to 4.8 parts, In the same manner as in Example 1, a polarizing film forming composition and a polarizing film were produced. Each evaluation result is shown in Table 1.

Example 6
Except for changing the dichroic dye (1-1) to 2.6 parts, the dichroic dye (2) to 4.5 parts, and the dichroic dye (1-2) to 2.6 parts, In the same manner as in Example 1, a polarizing film forming composition and a polarizing film were produced. Each evaluation result is shown in Table 1.

[Comparative Example 1]
Except for changing the dichroic dye (1-1) to 1.4 parts, the dichroic dye (2) to 1.2 parts, and the dichroic dye (1-2) to 1.4 parts, In the same manner as in Example 1, a polarizing film forming composition and a polarizing film were produced. Each evaluation result is shown in Table 1.

  As shown in Table 1, the polarizing film-forming compositions of Examples 1 to 6 are excellent in long-term stability because A (380) is 1.2 or more, and can be obtained even after long-term storage. It was found that the occurrence of orientation defects in the polarizing film can be effectively suppressed. Moreover, since the polarizing film formation composition of Examples 1-4 has A (650) of 0.8 or less, it turned out that the foreign material in this composition can be visually recognized easily.

Claims (10)

A polymerizable liquid crystal compound, a dichroic dye, a photopolymerization initiator, and an organic solvent are included, and the following formula (1)
A (380) ≧ 1.2 (1)
[Wherein, A (380) represents the absorbance at 380 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
The composition for polarizing film formation which satisfy | fills. Furthermore, the following formula (2)
0.8 ≧ A (650) (2)
[Wherein A (650) represents the absorbance at 650 nm of a solution obtained by diluting the composition for forming a polarizing film with the organic solvent so that the concentration becomes 0.4% by mass]
The composition for forming a polarizing film according to claim 1, wherein   The composition for forming a polarizing film according to claim 1, wherein the polymerizable liquid crystal compound is a compound exhibiting smectic liquid crystallinity.   Content of solid content in the composition for polarizing film formation is a composition for polarizing film formation in any one of Claims 1-3 which is 5-50 mass% of the mass of this composition for polarizing film formation.   Content of a polymeric liquid crystal compound is a composition for polarizing film formation in any one of Claims 1-4 which is 50-99 mass% of the mass of solid content in the composition for polarizing film formation.   The composition for forming a polarizing film according to any one of claims 1 to 5, wherein the content of the dichroic dye is 1 to 20% by mass of the mass of the solid content in the composition for forming a polarizing film.   The polarizing film which is a hardened | cured material of the composition for polarizing film formation in any one of Claims 1-6. A step (ii) of forming a coating film of the composition for forming a polarizing film according to claim 1, drying and removing an organic solvent from the coating film, and a state in which a polymerizable liquid crystal compound is in a smectic liquid crystal phase The manufacturing method of a polarizing film including the process (iii) of carrying out orientation hardening by.   The method of Claim 8 including the process (i) of storing the composition for polarizing film formation in any one of Claims 1-6 in the state which satisfy | fills said Formula (1) and / or (2). .   A polarizing plate comprising the polarizing film according to claim 7, a substrate, and an alignment film.