KR20200115575A - Composition for forming a polarizing film, a polarizing film, a polarizing plate, and a manufacturing method thereof - Google Patents

Abstract

A polymerizable liquid crystal compound exhibiting smectic liquid crystal properties, a dichroic dye, and at least two or more organic solvents, wherein the organic solvent is -20°C or more and 50°C or less higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound A composition for forming a polarizing film comprising an organic solvent A having a boiling point and an organic solvent B having a boiling point higher than 50° C. than the isotropic phase transition temperature of the polymerizable liquid crystal compound.

Description

Composition for forming a polarizing film, a polarizing film, a polarizing plate, and a manufacturing method thereof

The present invention relates to a composition for forming a polarizing film, a polarizing film, a polarizing plate, and a method of manufacturing the same.

Conventionally, in a flat panel display device (FPD), a polarizing plate is used by being attached to an image display device such as a liquid crystal cell or an organic EL display device. As such a polarizing plate, a protective layer such as a triacetyl cellulose film is formed on at least one surface of a polarizer in which a compound exhibiting dichroic properties such as iodine or a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, through an adhesive layer. Polarizing plates having a laminated configuration are widely used.

In recent years, with the demand for thinner flat panel display devices, additional thinning is also required for a polarizing plate or a polarizing film, which is one of its constituent elements, and various polarizing plates and polarizing films have been proposed for such a demand. For example, in Patent Literature 1, a polarizer including a polymer formed of a polymerizable liquid crystal compound showing a smectic liquid crystal phase and a dichroic dye is disclosed. In addition, Patent Document 2 discloses a polymerizable liquid crystal composition capable of dissolving a polymerizable liquid crystal compound showing a smectic phase and a dichroic dye in a solvent to form a polarizing film by a wet coating method. In addition, Patent Literature 3 discloses a thin polarizing film containing a plurality of dichroic dyes and a polymerizable liquid crystal compound showing a smectic liquid crystal phase, and exhibiting polarization performance in all visible light.

Japanese Patent No. 4719156 Japanese Unexamined Patent Publication No. 2012-083734 Japanese Unexamined Patent Publication No. 2013-210624

The polarizing plate or polarizing film (polarizer) disclosed in the above patent document is generally applied to a film such as a base film by applying a composition for forming a polarizing film containing a polymerizable liquid crystal compound and a dichroic dye together with a solvent. It is formed through a step of phase transitioning a polymerizable liquid crystal compound to a liquid crystal state by heating and drying the coating film. The inventors of the present invention have found that in such a step, if the solvent is volatilized from the coating film before the polymerizable liquid crystal compound is phase-transferred to the liquid crystal state, the polymerizable liquid crystal compound is easily precipitated as microcrystals. When such microcrystals have precipitated, it is difficult to obtain a satisfactory mixed-inclusion state of the polymerizable liquid crystal compound and the dichroic dye even after heating and drying, and it becomes the cause of generating dot defects or alignment defects in the obtained polarizing film. The precipitation of such microcrystals is considered to be due to the fact that the Smectic liquid crystal has a structure closer to the crystal compared to the general nematic liquid crystal, and is a particularly problem in a polarizing film formed of a polymerizable liquid crystal compound exhibiting Smectic liquid crystal properties. Becomes.

Therefore, it is an object of the present invention to provide a composition for forming a polarizing film capable of forming a polarizing film having no dot defects and orientation defects and having a high degree of alignment order.

The inventors of the present invention and the like have studied intensively in order to solve the above problems, and have come to complete the present invention. That is, the present invention provides the following preferred aspects.

[1] A polymerizable liquid crystal compound exhibiting smectic liquid crystal properties, a dichroic dye, and at least two organic solvents are included, and the organic solvent is -20°C or higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound. A composition for forming a polarizing film comprising an organic solvent A having a boiling point higher than C. C. and an organic solvent B having a boiling point higher than 50° C. than the isotropic phase transition temperature of the polymerizable liquid crystal compound.

[2] The content of the organic solvent A relative to 100 parts by mass of the total organic solvent contained in the composition for forming a polarizing film is 51 to 99 parts by mass, and the content of the organic solvent B is 1 to 49 parts by mass. Composition for forming a polarizing film.

[3] The boiling point of the organic solvent A is 0°C or more and 50°C or less higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound, and the boiling point of the organic solvent B exceeds 50°C than the isotropic phase transition temperature of the polymerizable liquid crystal compound. The composition for forming a polarizing film according to [1] or [2], which is high at 150°C or less.

[4] The composition for forming a polarizing film according to any one of [1] to [3], further comprising a polymerization initiator.

[5] The composition for forming a polarizing film according to any one of the above [1] to [4], in which the organic solvent A is a ketone solvent or an aromatic solvent.

[6] The composition for forming a polarizing film according to any one of [1] to [5], wherein the organic solvent B is selected from the group consisting of a glycol-based solvent, a ketone-based solvent, and an amide-based solvent.

[7] The composition for forming a polarizing film according to any one of [1] to [6], wherein the solid content of the composition for forming a polarizing film is 5 to 40% by mass.

[8] The composition for forming a polarizing film according to [7], wherein the proportion of the polymerizable liquid crystal compound in the solid content is 40 to 99.9 mass%.

[9] The composition for forming a polarizing film according to [7] or [8], wherein the ratio of the dichroic dye in the solid content is 1 to 20% by mass.

[10] As a cured product of the composition for forming a polarizing film according to any one of [1] to [9], a polarizing film in which a polymerizable liquid crystal compound and/or its polymer is oriented in a smectic liquid crystal state.

[11] The polarizing film according to [10], in which a Bragg peak is obtained in X-ray diffraction measurement.

[12] A polarizing plate comprising the polarizing film, a substrate, and an alignment film according to [10] or [11].

[13] Forming a coating film of the composition for forming a polarizing film according to any one of [1] to [9],

The coating film is heated and dried to a temperature equal to or higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film, and then lowered, thereby causing the polymerizable liquid crystal compound to phase transition to the Smectic liquid crystal phase, and

Forming a polarizing film by polymerizing a polymerizable liquid crystal compound while maintaining the smectic liquid crystal phase

Containing, the manufacturing method of a polarizing plate.

[14] As the method for producing a polarizing plate according to [13], in which a coating film of the composition for forming a polarizing film is formed on the photo-alignment film, the photo-alignment film,

Forming a coating film from a composition containing a polymer or a monomer and a solvent that generates an orientation regulating force by light,

Drying off the solvent from the coating film to obtain a dry coating film, and

Irradiating polarized ultraviolet rays to the dried coating film

Formed by a method comprising a, method.

Advantageous Effects of Invention According to the present invention, a composition for forming a polarizing film capable of forming a polarizing film having no dot defects and orientation defects and having a high degree of alignment order can be provided.

Hereinafter, an embodiment of the present invention will be described in detail. In addition, the scope of the present invention is not limited to the embodiments described herein, and various changes can be made without impairing the gist of the present invention.

<Composition for forming a polarizing film>

The composition for forming a polarizing film of the present invention contains a polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (A)") exhibiting smectic liquid crystal properties. By using a polymerizable liquid crystal compound that exhibits smectic liquid crystal properties, a polarizing film having high alignment order can be formed. The liquid crystal state represented by the polymerizable liquid crystal compound (A) is a smectic phase (smectic liquid crystal state), and it is more preferable to show a high-order smectic phase (high order smectic liquid crystal state) from the viewpoint of realizing a higher degree of alignment order. . Here, the higher-order Smectic phase is, 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 are meant, and among these, Smectic B phase, Smectic F phase, and Smectic I phase are more preferable. The liquid crystal property may be a thermotropic liquid crystal or a lyotropic liquid crystal, but a thermotropic liquid crystal is preferable from the viewpoint of enabling precise film thickness control. The polymerizable liquid crystal compound may be a monomer, but may be an oligomer in which a polymerizable group is polymerized or a polymer.

The polymerizable liquid crystal compound (A) is not particularly limited as long as it is a polymerizable liquid crystal compound showing smectic liquid crystal properties, and a known polymerizable liquid crystal compound can be used.

As the polymerizable liquid crystal compound (A), for example, a compound represented by the formula (A1) and a polymer of the compound (hereinafter, the compound and the polymer are collectively referred to as "polymerizable liquid crystal compound (A1)"). Can be lifted.

U ¹ -V ¹ -W ¹ -X ¹ -Y ¹ -X ² -Y ² -X ³ -W ² -V ² -U ² (A1)

[In formula (A1),

X ¹ , X ² and X ³ each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group is a halogen atom, The carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a C1-C4 alkyl group, a C1-C4 fluoroalkyl group, a C1-C4 alkoxy group, a cyano group, or a nitro group. , An oxygen atom, a sulfur atom, or a nitrogen atom may be substituted. 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.

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 alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and -CH ₂ -constituting the alkanediyl group is -O-, -CO-, -S -Or it may be substituted with NH-.]

In the polymerizable liquid crystal compound (A1), X ¹ , X ^2, and X ³ are each independently, preferably, a 1,4-phenylene group which may have a substituent, or a cyclohexane group which may have a substituent. 1,4-diyl group, and 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. . 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 a trans-cyclohexane-1,4-diyl group It is more preferable to be. As a substituent optionally having a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group, And halogen atoms such as a cyano group and a chlorine atom and a fluorine atom. It is preferably unsubstituted. Moreover, 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 crystal properties tend to be easily expressed.

Y ¹ and Y ² are, independently of each other, -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. It is more preferable that Y ¹ is -CH ₂ CH ₂ -, -COO-, or a single bond, and it is more preferable that Y ² is -CH ₂ CH ₂ -or CH ₂ O-. Moreover, when all of X ¹ , X ² and X ³ have the same structure, it is preferable that Y ¹ and Y ² have different structures. When Y ¹ and Y ² have structures different from each other, smectic liquid crystal properties tend to be easily expressed.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. It is preferable that both U ¹ and U ² are polymerizable groups, and it is preferable that both are radical polymerizable groups. As a polymerizable group, for example, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, etc. Can be mentioned. Among them, a radical polymerizable group is preferable, an acryloyloxy group, a methacryloyloxy group, a vinyl group, and a vinyloxy group are more preferable, and an acryloyloxy group and a methacryloyloxy group are preferable. The polymerizable group represented by U ¹ and the polymerizable group represented by U ² may be different from each other, but a group of the same type is preferable.

Examples of the alkanediyl group represented by V ¹ and V ² include methylene group, ethylene group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, 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 group And an icosan-1,20-diyl group. V ¹ and V ² are preferably an alkanediyl group having 2 to 12 carbon atoms, and more preferably an alkanediyl group having 6 to 12 carbon atoms.

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

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

As a polymerizable liquid crystal compound (A1), the compound represented by formula (A-1)-formula (A-25) is mentioned, for example. When the polymerizable liquid crystal compound (A1) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans chain.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

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 member 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) is preferable. . As the polymerizable liquid crystal compound (A1), one type may be used alone, or two or more types may be used in combination.

The polymerizable liquid crystal compound (A1) is obtained from Recl. Trav. Chim. It can be produced by a known method described in Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

The composition for forming a polarizing film of the present invention may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (A) as long as the effect of the present invention is not impaired. From the viewpoint of obtaining a polarizing film with high alignment order, the ratio of the polymerizable liquid crystal compound (A) to the total mass of the total polymerizable liquid crystal compound in the composition for forming a polarizing film is preferably 51% by mass or more, and more Preferably it is 70 mass% or more, More preferably, the polymerizable liquid crystal compound of 90 mass% or more is a polymeric compound (A), and all (100 mass %) may be a polymeric liquid crystal compound (A).

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing film of the present invention is preferably 40 to 99.9% by mass, more preferably 60 to 99.9% by mass, based on the solid content of the composition for forming a polarizing film, More preferably, it is 70 to 99 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 increase. In this specification, the solid content refers to the total amount of the components excluding the solvent from the composition for forming a polarizing film.

The composition for forming a polarizing film of the present invention contains a dichroic dye. Here, the dichroic dye means a dye having a property different from the absorbance in the long axis direction of the molecule and the absorbance in the short axis direction. The dichroic dye usable in the present invention is not particularly limited as long as it has the above properties, and may be a dye or a pigment. Two or more types of dyes or pigments may be used in combination, or dyes and pigments may be used in combination.

As the dichroic dye, it is preferable to have a maximum absorption wavelength (λ _MAX ) in the range of 300 to 700 nm. Examples of such a dichroic dye include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye and an anthraquinone dye.

Examples of azo dyes include monoazo dyes, bis azo dyes, tris azo dyes, tetrakis azo dyes and stilbenazo dyes, and bis azo dyes and tris azo dyes are preferable, for example, formula (I ) Represented by the compound (hereinafter, also referred to as "compound (I)") is mentioned.

K ¹ (-N=NK ² ) _p -N=NK ³ (I)

[In formula (I), K ¹ and K ³ each independently represent a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. 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 group which may have a substituent. p represents the integer of 1-4. When p is an integer of 2 or more, a plurality of K ² may be the same or different. In the range showing absorption in the visible region, -N=N- bond may be substituted with -C=C-, -COO-, -NHCO-, -N=CH- bond.]

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

Phenyl group, naphthyl group and monovalent heterocyclic group for K ¹ and K ³ , and p-phenylene group, naphthalene-1,4-diyl group and divalent heterocyclic group for K ² optionally have substituents, An alkyl group having 1 to 4 carbon atoms; Alkoxy groups having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, and a butoxy group; C1-C4 fluorinated alkyl groups, such as a trifluoromethyl group; Cyano group; Nitro group; Halogen atom; A substituted or unsubstituted amino group such as an amino group, diethylamino group, or pyrrolidino group (a substituted amino group refers to an amino group having 1 or 2 alkyl groups having 1 to 6 carbon atoms, or two substituted alkyl groups bonded to each other and having 2 to 8 carbon atoms. It means an amino group which forms an alkanediyl group of. Unsubstituted amino group is -NH ₂ .) etc. are mentioned.

Among compound (I), a compound represented by any of formulas (I-1) to (I-6) is preferred.

[Formula 6]

[In formulas (I-1) to (I-8),

B ¹ to B ³⁰ are each independently a hydrogen atom, a C 1 to C 6 alkyl group, a C 1 to C 4 alkoxy group, a cyano group, a nitro group, a substituted or unsubstituted amino group (definition of a substituted amino group and an unsubstituted amino group Is the same as above), a chlorine atom or a trifluoromethyl group.

n1 to n4 each independently represent the integer of 0 to 3.

When n1 is 2 or more, a plurality of B ² may be the same or different from each other,

When n2 is 2 or more, a plurality of B ⁶ may be the same or different from each other,

When n3 is 2 or more, a plurality of B ⁹ may be the same or different from each other,

When n4 is 2 or more, a plurality of B ¹⁴ may be the same or different.]

As the anthraquinone dye, a compound represented by formula (I-9) is preferable.

[Formula 7]

[In formula (I-9),

R ¹ to R ⁸ are each independently 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.]

As the oxazone dye, a compound represented by formula (I-10) is preferable.

[Formula 8]

[In 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.]

As the acridine dye, a compound represented by formula (I-11) is preferable.

[Formula 9]

[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 formulas (I-9), (I-10) and (I-11), examples of the alkyl group having 1 to 6 carbon atoms of R ^x include methyl group, ethyl group, propyl group, butyl group, pentyl group, and hexyl group. And the like, and examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a toluyl group, a xylyl group, and a naphthyl group.

As the cyanine dye, a compound represented by formula (I-12) and a compound represented by formula (I-13) are preferred.

[Formula 10]

[In formula (I-12),

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

[Formula 11]

n5 represents the integer of 1-3.]

[Formula 12]

[In formula (2-13),

D ³ and D ⁴ each independently represent a group represented by any of formulas (1-13a) to (1-13h).

[Formula 13]

n6 represents the integer of 1-3.]

Although the content of the dichroic dye in the composition for forming a polarizing film of the present invention can be appropriately determined depending on the type of the dichroic dye to be used, etc., it is preferably 1 to 60% by mass with respect to the solid content of the composition for forming a polarizing film. And, more preferably 1 to 20% by mass, still more preferably 1 to 15% by mass. When the content of the dichroic dye is within the above range, the orientation of the polymerizable liquid crystal compound is not easily disturbed, and a polarizing film having a high degree of alignment order can be obtained.

The composition for forming a polarizing film of the present invention contains at least two types of organic solvents. As the two types of organic solvents, an organic solvent A having a boiling point higher than -20°C and 50°C higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound, and 50°C higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound At least the organic solvent B having a boiling point higher than that is contained. The composition for forming a polarizing film of the present invention contains at least two types of organic solvents having different boiling points, so that the coating film of the composition for forming a polarizing film is heated and dried to phase change the polymerizable liquid crystal compound into a liquid crystal state (hereinafter, ``heating It is also referred to as "drying process"), but the solvent is not easily volatilized before, but in the heat drying process, the solvent is easily dried and removed, and a polarizing film excellent in polarization performance can be obtained which does not easily generate orientation defects or dot defects. When the composition for forming a polarizing film of the present invention contains two or more types of polymerizable liquid crystal compounds, the organic solvents A and B are each isotropic in a mixed state of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film. It is selected based on the phase transition temperature.

The organic solvent A usually dissolves a polymerizable liquid crystal compound and a dichroic dye to easily generate a favorable mixing state of the polymerizable liquid crystal compound and a dichroic dye in the coating film, and the solid content of the composition for forming a polarizing film. It acts to adjust the concentration and viscosity. In particular, compounds exhibiting smectic liquid crystal properties generally tend to have a high viscosity, and by including the organic solvent A in the composition for forming a polarizing film, the handling property of the composition becomes good, and as a result, formation of the polarizing film becomes easy. In order to suppress the volatilization of the organic solvent from the coating film before the heat-drying step of the coating film of the composition for forming a polarizing film, the boiling point of the organic solvent A is lower than the isotropic phase transition temperature of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film. 20°C or more and 50°C or less, preferably 0°C or more and 50°C or less, more preferably 10°C or more and 50°C or less, and more preferably 20°C or more and 40°C or less. When the boiling point of the organic solvent A is lower than the isotropic phase transition temperature of the polymerizable liquid crystal compound by more than -20°C, the organic solvent is likely to volatilize before the heating and drying step, and microcrystals of the polymerizable liquid crystal compound are likely to precipitate. In addition, if the boiling point of the organic solvent A is higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound by more than 50°C, the volatilization of the solvent before the heating and drying step can be suppressed, but the solvent is not easily volatilized in the heat drying step. Orientation defects are likely to occur, and the heating temperature must be increased to remove the solvent, so that damage to films such as a substrate is likely to occur. At the same time, since the amount of the solvent remaining after the heating and drying step can be reduced, the occurrence of orientation defects caused by the remaining solvent can be suppressed. Organic solvent A may be used individually by 1 type, and may be used in combination of 2 or more types.

The organic solvent B is a high boiling point solvent, and has an action of bringing about a moisturizing effect in the coating film before the heating and drying step. From the viewpoint of suppressing volatilization from the coating film before the heating and drying step, the boiling point of the organic solvent B is higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film by more than 50°C, preferably Is 55°C or more, preferably 150°C or less, more preferably 60°C or more and 150°C or less, and still more preferably 60°C or more and 120°C or less. By including the organic solvent B having a boiling point higher in the above range than the isotropic phase transition temperature of the polymerizable liquid crystal compound, it is possible to effectively suppress the volatilization of the organic solvent from the coating film before the heating and drying step, and the polymerizable liquid crystal compound and It is possible to maintain a good mixing and inclusion state of the dichroic dye. Thereby, it is possible to effectively suppress the occurrence of dot defects in the obtained polarizing film. Organic solvent B may be used individually by 1 type, and may be used in combination of 2 or more types.

The difference between the boiling point of the organic solvent A and the boiling point of the organic solvent B is preferably 20°C or higher, more preferably 30°C or higher, preferably 120°C or lower, and more preferably 100°C or lower. If the boiling points of the organic solvents A and B are in the above relationship, the effect of suppressing the generation of microcrystals of the polymerizable liquid crystal compound before the heating drying step of the coating film of the composition for forming a polarizing film and the ease of removal of the solvent in the heating drying step It is easy to balance the effects, and dot defects and alignment defects are not easily generated in the obtained polarizing film.

The organic solvents A and B are known organic solvents capable of dissolving the polymerizable liquid crystal compound and the dichroic dye, respectively, based on the isotropic phase transition temperature of the polymerizable liquid crystal compound, depending on the polymerizable liquid crystal compound and the dichroic dye to be used. You can choose appropriately from As an organic solvent, the following solvents are mentioned, for example:

Methyl isobutyl ketone (116 ℃), cyclohexanone (156 ℃), cyclopentanone (131 ℃), methyl amyl ketone (151 ℃), isophorone (215 ℃), γ-butyrolactone (GBL) (204 Ketone solvents such as deg. C);

Xylene (144 °C), mesitylene (165 °C), cumene (152 °C), ethylbenzene (136 °C), anisole (154 °C), aniline (184 °C), benzaldehyde (178 °C), benzyl alcohol (205 ℃), methyl benzoate (199 ℃), ethyl benzoate (213 ℃), propyl benzoate (230 ℃), butyl benzoate (250 ℃), nitrobenzene (211 ℃), tetralin (207 ℃), etc. ;

Long-chain hydrocarbon solvents such as octane (125°C), nonane (151°C), decane (174°C), undecane (196°C), and dodecane (216°C);

Ethylene glycol monomethyl ether (124 ℃), ethylene glycol monoethyl ether (202 ℃), ethylene glycol-n-propyl ether (151 ℃), ethylene glycol-i-propyl ether (141 ℃), ethylene glycol-n-butyl Ether (171 ℃), ethylene glycol monomethyl ether (124 ℃), diethylene glycol dimethyl ether (162 ℃), diethylene glycol diethyl ether (189 ℃), dipropylene glycol dimethyl ether (171 ℃), diethylene glycol Monomethyl ether (194 ℃), diethylene glycol monoethyl ether (202 ℃), diethylene glycol monobutyl ether (230 ℃), diethylene glycol ethyl methyl ether (176 ℃), diethylene glycol butyl methyl ether (212 ℃ ), propylene glycol monomethyl ether (120 ℃), propylene glycol dimethyl ether (120 ℃), dipropylene glycol monomethyl ether (188 ℃), dipropylene glycol dimethyl ether (171 ℃), propylene glycol dimethyl ether (97 ℃) , Tripropylene glycol dimethyl ether (215 ℃), triethylene glycol monomethyl ether (249 ℃), triethylene glycol dimethyl ether (216 ℃), tetraethylene glycol dimethyl ether (276 ℃), propylene glycol monomethyl ether acetate (146 ℃), ethylene glycol monomethyl ether acetate (145 ℃), ethylene glycol monomethyl ether acetate (145 ℃), diethylene glycol monoethyl ether acetate (217 ℃), diethylene glycol monobutyl ether acetate (245 ℃), etc. Glycol-based solvents;

Propyl acetate (102 °C), butyl acetate (126 °C), amyl acetate (149 °C), ethyl lactate (155 °C), methylmethoxypropionate (143 °C), ethylethoxypropionate (170 °C), Isoamylpropionate (156 ℃), isoamylisobutyrate (179 ℃), ethyl butyrate (121 ℃), propyl butyrate (143 ℃), butyl butyrate (165 ℃), ethylene carbonate (244 ℃), propylene carbonate Ester solvents such as (242°C);

Amide solvents such as N,N-dimethylformamide (153°C), N,N-dimethylacetamide (165°C), N-methylpyrrolidone (202°C), and γ-butyrolactam (245°C); And

Halogen solvents such as chlorobenzene (131°C) and 1,1,2,2,-tetrachloroethane (147°C).

As the organic solvent A, it is more advantageous to select one having high solubility in a polymerizable liquid crystal compound and a dichroic dye. In a preferred embodiment of the present invention, the organic solvent A is a ketone solvent or an aromatic solvent, and more preferably an aromatic solvent. In addition, as the organic solvent B, it is more advantageous to select one having a high boiling point with respect to the isotropic phase transition temperature of the polymerizable liquid crystal compound and high solubility in the polymerizable liquid crystal compound and the dichroic dye. In a preferred embodiment of the present invention, the organic solvent B is selected from the group consisting of a glycol-based solvent, a ketone-based solvent and an amide-based solvent, more preferably a glycol-based solvent with a boiling point of 150°C or higher, a ketone-based solvent, and an amide. It is a system solvent.

The content of the organic solvent A in the composition for forming a polarizing film of the present invention is preferably 51 to 99 parts by mass, more preferably 60 parts by mass, based on 100 parts by mass of the total organic solvent contained in the composition for forming a polarizing film. It is at least 70 parts by mass, more preferably at least 70 parts by mass, more preferably at most 95 parts by mass, still more preferably at most 90 parts by mass. Further, the content of the organic solvent B is preferably 1 to 49 parts by mass, more preferably 5 parts by mass or more, further preferably 10 parts by mass, based on 100 parts by mass of the total organic solvent contained in the composition for forming a polarizing film. It is not less than mass parts, more preferably not more than 40 parts by mass, still more preferably not more than 30 parts by mass. When the organic solvents A and B are each contained within the range of the above content, by suppressing the volatilization of the solvent in the coating film before the heat-drying step, a favorable mixed encapsulation state of the polymerizable liquid crystal compound and the dichroic dye can be obtained. In the heating and drying process, more than necessary heating is not required, and it becomes possible to sufficiently remove the solvent even under a temperature near the phase transition temperature of the polymerizable liquid crystal compound, thereby suppressing orientation defects caused by the residual solvent, and improving polarization performance. An excellent polarizing film can be obtained. When the organic solvent A and/or the organic solvent B contains two or more types, the content means the total amount of each of the organic solvent A and/or the organic solvent B. Unless the effect of the present invention is impaired, the composition for forming a polarizing film of the present invention may contain organic solvents other than organic solvents A and B.

It is preferable that the composition for forming a polarizing film of the present invention contains an organic solvent in an amount such that the solid content is 5 to 40 mass%. In other words, the content of the organic solvent in the composition for forming a polarizing film of the present invention (the total amount of organic solvents A and B, and other organic solvents in the case of containing) is based on the total mass of the composition for forming a polarizing film. It is preferably 60 to 95% by mass. When the content of the organic solvent is within the above range, the volatilization of the solvent can be suppressed in the coating film before heat drying, and the solvent is easily dried and removed without heating more than necessary in the heat drying step, thereby reducing the amount of residual solvent. I can. Thereby, a polarizing film excellent in polarization performance can be obtained.

It is preferable that the composition for forming a polarizing film of the present invention contains a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable liquid crystal compound, and a photoinitiator is preferable because a polymerization reaction can be initiated under a lower temperature condition. Specifically, a photopolymerization initiator capable of generating an active radical or an acid by the action of light may be mentioned. Among them, a photopolymerization initiator which generates a radical by the action of light is preferable. The polymerization initiator can be used alone or in combination of two or more.

Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts and sulfonium salts.

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-butylper Oxycarbonyl)benzophenone and 2,4,6-trimethylbenzophenone, and the like.

As an alkylphenone compound, diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, 2-dimethylamino-2-benzyl-1-(4- Morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2- Hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenylketone and 2-hydroxy-2-methyl-1-[4 Oligomers of -(1-methylvinyl)phenyl]propan-1-one, and the like.

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

As a triazine compound, 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-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine And the like.

Commercially available ones can be used as the polymerization initiator. As commercially available polymerization initiators, "Irgacure (registered trademark) 907", "Irgacure (registered trademark) 184", "Irgacure (registered trademark) 651", "Irgacure (registered trademark) ) 819", "Irgacure (registered trademark) 250", "Irgacure (registered trademark) 369" (Chiba Japan Co., Ltd.); "Sakeall (registered trademark) BZ", "Sakeall (registered trademark) Z", "Sakeall (registered trademark) BEE" (Seiko Chemical Co., Ltd.); "Kayacure (registered trademark) BP100" (Nippon Explosives Co., Ltd.); "Kayacure (registered trademark) UVI-6992" (manufactured by Dow Corporation); "Adeka Optomer SP-152", "Adeka Optomer SP-170" (ADEKA Co., Ltd.); "TAZ-A", "TAZ-PP" (Nippon Sibel Heg Screw); And "TAZ-104" (Sanwa Chemical Co., Ltd.), and the like.

When the composition for forming a polarizing film contains a polymerization initiator, its content can be appropriately determined according to the kind and amount of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film, but 100 parts by mass of the polymerizable liquid crystal compound On the other hand, 0.1 to 30 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is still more preferable. When the content of the polymerizable initiator is within the above range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound.

When the composition for forming a polarizing film contains a photoinitiator, it may further contain a photosensitizer. By using a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further accelerated. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (2,4-diethyl thioxanthone, 2-isopropyl thioxanthone, etc.); Anthracene compounds such as anthracene and alkoxy group-containing anthracene (dibutoxyanthracene, etc.); Phenothiazine, rubrene, and the like. Photosensitizers can be used alone or in combination of two or more.

The content of the photosensitizer in the composition for forming a polarizing film of the present invention may be appropriately determined depending on the kind and amount of the photopolymerization initiator and the polymerizable liquid crystal compound, but is 0.1 to 100 parts by mass of the polymerizable liquid crystal compound. 30 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is still more preferable.

Moreover, the composition for forming a polarizing film of this invention may contain a leveling agent. The leveling agent has a function of making the coating film obtained by adjusting the fluidity of the composition for forming a polarizing film and applying the composition for forming a polarizing film more flat, and specifically, a surfactant is mentioned. As the leveling agent, at least one member 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 is preferable. Leveling agents may be used alone or in combination of two or more.

As a leveling agent containing a polyacrylate compound as a main component, "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", "BYK -361N", "BYK-380", "BYK-381", and "BYK-392" (BYK Chemie), and the like.

As a leveling agent containing a fluorine atom-containing compound as a main component, "Megapak (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 the same "F-483" (DIC Corporation); "Serpron (registered trademark) S-381", East "S-382", East "S-383", East "S-393", East "SC-101", East "SC-105", "KH- 40" and "SA-100" (AGC Seimi Chemical Co., Ltd.); "E1830", "E5844" (Daikin Fine Chemical Research Institute); "Ftop EF301", "Ftop EF303", "Ftop EF351", and "Ftop EF352" (Mitsubishi Material Electronics, Hwasung Co., Ltd.), and the like.

The content of the leveling agent in the composition for forming a polarizing film of the present invention is preferably 0.05 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass with respect to 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 does not occur easily, and a more smooth polarizing film can be obtained.

In order to progress the polymerization reaction of the composition for forming a polarizing film more stably, the composition may contain an appropriate amount of a polymerization inhibitor, whereby it becomes easy to control the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound.

Examples of the polymerization inhibitor include hydroquinone, alkoxy group-containing hydroquinone, alkoxy group-containing catechol (eg, butylcatechol, etc.), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxy Radical supplements such as radicals; Thiophenols; β-naphthylamines and β-naphthols.

When the composition for forming a polarizing film contains a polymerization inhibitor, the content can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound, and the amount of the photosensitizer used, but per 100 parts by mass of the polymerizable liquid crystal compound , 0.1 to 30 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 0.5 to 8 parts by mass is still more preferable. When the content of the polymerization inhibitor is within this range, polymerization can be performed without disturbing the orientation of the polymerizable liquid crystal compound.

The composition for forming a polarizing film may contain other additives other than a photoinitiator, a leveling agent, a photosensitizer, and a polymerization inhibitor. As other additives, antioxidants, release agents, stabilizers, coloring agents such as bluing agents, flame retardants, lubricants, and the like may be mentioned. When the composition for forming a polarizing film contains other additives, the content of the other additive is preferably more than 0% by mass and not more than 20% by mass, more preferably 0% by mass, based on the solid content of the composition for forming a polarizing film. It exceeds and is 10 mass% or less.

The solid content of the composition for forming a polarizing film of the present invention is preferably 5 to 40% by mass. When the solid content concentration of the composition for forming a polarizing film is more than the above lower limit, the solvent volatilizes before the heat-drying process of the coating film of the composition for forming a polarizing film to prevent precipitation of microcrystals of the polymerizable liquid crystal compound, thereby preventing dot defects in the polarizing film. The occurrence can be suppressed. Moreover, when the solid content is less than or equal to the above upper limit, it is easy to remove the organic solvent in the heat drying step, and orientation defects are less likely to occur in the obtained polarizing film. In addition, since a compound exhibiting Smectic liquid crystal properties generally has a high viscosity, there is also an advantage in that the solid content concentration is within the above range to facilitate application, resulting in an easy formation of a polarizing film. In the present invention, the solid content of the composition for forming a polarizing film is more preferably 10% by mass or more, still more preferably 15% by mass or more, more preferably 35% by mass or less, still more preferably 30% by mass or less. to be. The solid content concentration can be adjusted mainly by the blending amount of an organic solvent or a polymerizable liquid crystal compound.

The composition for forming a polarizing film of the present invention can usually be prepared by mixing and stirring a polymerizable liquid crystal compound, a dichroic dye and an organic solvent, and the above-described additives as necessary.

In the composition for forming a polarizing film of the present invention, dot defects or alignment defects are less likely to occur, and a polarizing film having high alignment order can be obtained. Accordingly, the present invention also includes a polarizing film obtained by curing the composition for forming a polarizing film of the present invention (that is, a cured product of the composition for forming a polarizing film). In the polarizing film of the present invention, it is preferable that the polymerizable liquid crystal compound forming this and/or the polymer is aligned in a smectic liquid crystal state. By aligning in a smectic liquid crystal state, the polarizing film of the present invention shows a high degree of alignment order.

In the polarizing film having a high degree of orientation, in X-ray diffraction measurement, Bragg peaks derived from higher order structures such as hexatic phase and crystal phase are obtained. The Bragg peak means a peak derived from the plane periodic structure of molecular orientation. The polarizing film formed from the composition for forming a polarizing film of the present invention preferably exhibits a Bragg peak in X-ray diffraction measurement, and the polymerizable liquid crystal compound and/or its polymer molecularly aligns in the direction in which light is absorbed. It is more preferable that it is horizontal orientation. In the present invention, a polarizing film having a molecular orientation of 3.0 to 6.0 Å is preferable.

The polarizing film of the present invention can be produced, for example, according to the method of forming a polarizing film in the method of producing a polarizing plate of the present invention described later.

The present invention also targets a polarizing plate comprising the polarizing film of the present invention. In one embodiment of the present invention, the polarizing plate of the present invention includes a substrate and an alignment film in addition to the polarizing film of the present invention, and particularly preferably includes a substrate and a photo-alignment film.

The polarizing plate of the present invention is, for example, forming a coating film of the composition for forming a polarizing film of the present invention,

The coating film is heated and dried to a temperature equal to or higher than the nematic-isotropic phase transition temperature of the polymerizable liquid crystal compound contained in the polarizing film-forming composition, and then lowered to make the polymerizable liquid crystal compound in the Smectic liquid crystal phase (Smectic liquid crystal state) To phase change, and

Forming a polarizing film by polymerizing a polymerizable liquid crystal compound while maintaining the Smectic liquid crystal phase (Smectic liquid crystal state)

It can be produced by a method containing.

The formation of the coating film of the composition for forming a polarizing film can be performed by applying the composition for forming a polarizing film, for example, on a substrate or on an alignment film described later. In addition, when the polarizing plate of the present invention contains a retardation film or the like, a composition for forming a polarizing film may be directly applied thereon.

The substrate is usually a transparent substrate. When the substrate is not provided on the display surface of the display element, for example, when a laminate from which the substrate is removed from the polarizing film is provided on the display surface of the display element, the substrate may not be transparent. The transparent substrate refers to a substrate having transparency that can transmit light, particularly visible light, and the transparency refers to a property in which the transmittance of light over a wavelength of 380 to 780 nm is 80% or more. As a specific transparent base material, a translucent resin base material is mentioned. Examples of the resin constituting the translucent resin substrate include polyolefins such as polyethylene and polypropylene; Cyclic olefin resins such as norbornene-based polymers; Polyvinyl alcohol; Polyethylene terephthalate; Polymethacrylic acid ester; Polyacrylic acid ester; Cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; Polyethylene naphthalate; Polycarbonate; Polysulfone; Polyethersulfone; Polyether ketone; And polyphenylene sulfide and polyphenylene oxide. From the viewpoint of availability and transparency, polyethylene terephthalate, polymethacrylic acid ester, cellulose ester, cyclic olefin resin, or polycarbonate is preferable. The cellulose ester is one in which some or all of the hydroxyl groups contained in the cellulose are esterified, and can be easily obtained from the market. Moreover, a cellulose ester base material can also be easily obtained from the market. As a commercially available cellulose ester base material, "Fuji-Tac film" (Fuji Photographic Film Co., Ltd.); "KC8UX2M", "KC8UY", and "KC4UY" (Konica Minolta Opto Co., Ltd.), etc. are mentioned.

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

As a method of applying the composition for forming a polarizing film to a substrate, etc., known methods such as spin coating method, extrusion method, gravure coating method, die coating method, bar coating method, coating method such as applicator method, and printing method such as flexo method. This is how it was done.

Subsequently, the coating film obtained from the composition for forming a polarizing film is heated to a temperature equal to or higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film to dry and remove the solvent, and at the same time, the polymerizable liquid crystal compound is transferred to the liquid phase. Let it. Thereafter, the temperature is lowered, and the polymerizable liquid crystal compound is phase-transferred to a smectic phase (smectic liquid crystal state).

The heating temperature of the coating film can be appropriately determined in consideration of the polymerizable liquid crystal compound to be used and the material of the film such as a substrate for forming the coating film. In order to sufficiently bring the polymerizable liquid crystal compound into an isotropic state while sufficiently removing the organic solvent, the heating temperature is preferably 1° C. or higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound, and more preferably 5° C. or higher. , More preferably 7°C or higher. The upper limit of the heating temperature is not particularly limited, but in order to avoid damage to the coating film, substrate, etc. caused by heating, it is preferably 150°C or less, and more preferably 130°C or less.

The heating time can be appropriately determined depending on the heating temperature, the type of the polymerizable liquid crystal compound to be used, the type of the organic solvent, the boiling point and the amount thereof, but is usually 0.5 to 10 minutes, preferably 1 to 5 minutes.

Prior to heating the polymerizable liquid crystal compound above the isotropic phase transition temperature, a pre-drying step for appropriately removing the solvent in the coating film under conditions that the polymerizable liquid crystal compound contained in the coating film obtained from the film-forming composition does not polymerize is performed. You may prepare. By providing the drying step, the orientation of the polymerizable liquid crystal compound can be improved. As a drying method, a natural drying method, a ventilation drying method, a heat drying and a vacuum drying method, etc. are mentioned, and the drying temperature (heating temperature) in the drying step is the type of the polymerizable liquid crystal compound to be used, the type of the organic solvent, Although it can be suitably determined depending on the boiling point and its amount, etc., it is usually 30 to 150°C, preferably 50 to 130°C from the viewpoint of suppressing precipitation of microcrystals of the polymerizable liquid crystal compound. The drying time can be appropriately determined depending on the drying temperature, the kind of the organic solvent to be used, etc., but is usually 0.1 to 5 minutes, preferably 0.1 to 3 minutes.

Next, in the dry coating film obtained by the heat drying, the cured film of the composition for forming a polarizing film is formed as a polarizing film by polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound. As a polymerization method, a photopolymerization method is preferable. In photopolymerization, as the light irradiated to the dry coating film, the type of the photopolymerization initiator contained in the dried coating film, the type of the polymerizable liquid crystal compound (particularly, the type of the polymerizable group of the polymerizable liquid crystal compound) and the amount thereof It is appropriately selected according to. Specific examples thereof include at least one type of light or active electron beam selected from the group consisting of visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, and γ-ray. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction, and one widely used in the art as a photopolymerization device can be used, and for forming a polarizing film so that photopolymerization is possible by ultraviolet light. It is preferable to select the kind of polymerizable liquid crystal compound or photoinitiator contained in the composition. Moreover, at the time of polymerization, the polymerization temperature can also be controlled by irradiating light while cooling the dry coating film by an appropriate cooling means. When the polymerization of the polymerizable liquid crystal compound is carried out at a lower temperature by employing such a cooling means, even if a substrate having relatively low heat resistance is used, a polarizing film can be appropriately formed. During photopolymerization, a patterned polarizing film may 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 ultra-high 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 440 nm. An LED light source that emits light, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, and the like are mentioned.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/cm 2. The ultraviolet irradiation intensity is preferably the intensity in the wavelength range effective for activation of the photoinitiator. The time to irradiate light is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, and still more preferably 0.1 second 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 2.

By performing photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining the liquid crystal state of a smectic phase, preferably a high-order smectic phase, and a polarizing film is formed. The polarizing film obtained by polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state is accompanied by the action of the dichroic dye, and a conventional host guest type polarizing film, that is, a polarizing film comprising a nematic liquid crystal state, and In comparison, there is an advantage in that the polarization performance is high. In addition, there is also an advantage in that the strength is excellent compared to that of coating only a dichroic dye or a lyotropic liquid crystal.

The thickness of the polarizing film can be appropriately selected according to the display device to be applied, and is preferably 0.5 to 10 µm, more preferably 1 to 5 µm, and still more preferably 1 to 3 µm.

It is preferable that the coating film of the composition for forming a polarizing film is formed on the alignment film. The alignment film has an alignment regulating force that liquid crystal aligns a polymerizable liquid crystal compound in a desired direction. It is preferable that the alignment film has a solvent resistance that is not dissolved by an organic solvent contained in the composition for forming a polarizing film, and has heat resistance in heat treatment for removal of the solvent or alignment of the polymerizable liquid crystal compound. Examples of such an alignment layer include an alignment layer containing an alignment polymer, a photo alignment layer formed of a composition containing a polymer and a solvent that generates an alignment control force by light, and a groove alignment layer having an uneven pattern or a plurality of grooves on the surface, and stretching in the orientation direction. A stretched film and the like are mentioned, and a photo-alignment film is preferable from the viewpoint that static electricity and foreign matter are not easily generated, and the quality as an optical film is excellent.

Orienting polymers 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, and polyoxa. Sol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters are mentioned. Among them, polyvinyl alcohol is preferred. Orienting polymers can be used alone or in combination of two or more.

The alignment film containing an alignment polymer is usually applied to a substrate with a composition in which the alignment polymer is dissolved in a solvent (hereinafter, it may be referred to as ``orientation polymer composition'') to remove the solvent, or the alignment polymer composition is used as a substrate. It is obtained by applying to, removing a solvent, and rubbing (rubbing method). As the solvent, the same organic solvents that can be used in the composition for forming a polarizing film include those described above.

The concentration of the oriented polymer in the oriented polymer composition should be within a range in which the oriented polymer material can be completely dissolved in a solvent, but it is preferably 0.1 to 20% in terms of solid content relative to the solution, and more preferably about 0.1 to 10%. desirable.

As the alignment polymer composition, a commercially available alignment film material may be used as it is. As a commercially available alignment film material, Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optimer (registered trademark, manufactured by JSR Corporation), etc. are mentioned.

As a method of applying the oriented polymer composition to the substrate, the same ones as exemplified as the method of applying the composition for forming a polarizing film to the substrate may be mentioned.

As a method of removing the solvent contained in the oriented polymer composition, a natural drying method, a ventilation drying method, a heat drying method, a vacuum drying method, and the like may be mentioned.

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

As a method of imparting the orientation regulating force by the rubbing method, a method of contacting a film of an oriented polymer formed on the surface of the base material by applying an oriented polymer composition to the base material and annealing it on a rotating rubbing roll in which the rubbing cloth is wound and rotated. .

The photo-alignment film is usually applied on a film such as a substrate by applying a composition containing a polymer or a monomer and a solvent that has a photoreactive group and generates an alignment regulating force due to light (hereinafter, also referred to as a ``photo-alignment film-forming composition''). It can form by drying and removing a solvent from the coating film obtained by forming the coating film, and then irradiating the obtained dry coating film with polarized ultraviolet rays. The photoalignment film is more preferable because the direction of the orientation regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized ultraviolet rays to be irradiated.

The photoreactive group refers to a group that generates liquid crystal alignment ability by irradiation with light. Specifically, a group involved in the photoreaction which is the origin of the liquid crystal orientation ability, such as the orientation of molecules generated by light irradiation or isomerization reaction, dimerization reaction, photocrosslinking reaction or photodecomposition reaction, is mentioned. Among them, a group involved in a dimerization reaction or a photocrosslinking reaction is preferable from the viewpoint of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferred, and a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N Bond) and a group having at least one selected from the group consisting of 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 a group having a structure such as an aromatic cipro 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 formazane group, and a group having an azoxybenzene structure. As a photoreactive group which has a C=O bond, a benzophenone group, a coumarin group, an anthraquinone group, a maleimide group, etc. are mentioned. These groups may have substituents 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, the photoreactive group involved in the light dimerization reaction is preferable, and the amount of polarization irradiation required for photo-alignment is relatively small, and a photo-alignment film excellent in thermal stability and time-lapse stability is easy to obtain. And chalcone groups are preferred. As a polymer having a photoreactive group, it is particularly preferable that the terminal portion of the side chain of the polymer has a cinnamoyl group to form a cinnamic acid structure.

By applying the composition for forming a photo-alignment film on the base material, a photo-alignment causing layer can be formed on the base material. Examples of the solvent contained in the composition include the same organic solvents as those exemplified above as the organic solvent that can be used in the composition for forming a polarizing film, 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 determined depending on the type of the polymer or monomer or the thickness of the desired photoalignment film, but at least 0.2 with respect to the total mass of the composition for forming a photoalignment film It is preferable to set it as mass %, and the range of 0.3-10 mass% is more preferable. The composition for forming a photoalignment film may contain a polymeric material such as polyvinyl alcohol or polyimide, or a photosensitizer within a range in which the characteristics of the photoalignment film are not significantly impaired.

As a method of applying the composition for forming a photo-alignment film to the substrate, the same method as the method of applying the alignment composition to the substrate may be mentioned. As a method of removing the solvent from the applied composition for forming a photoalignment film, a natural drying method, a ventilation drying method, a heat drying method, a vacuum drying method, and the like may be mentioned.

The temperature at the time of drying and removing the solvent can be appropriately determined depending on the type or amount of the solvent to be used, but is usually 30 to 150°C, preferably 60 to 130°C. The time for dry removal is usually 0.1 to 10 minutes, preferably 0.5 to 5 minutes.

In order to irradiate polarized light, the solvent removed from the composition for forming a photo-alignment film applied on the substrate may be irradiated with polarized ultraviolet rays, or may be irradiated by irradiating polarized ultraviolet rays from the substrate side to transmit polarized ultraviolet rays. . This polarized ultraviolet ray is particularly preferable if it is substantially parallel light. The wavelength of the polarized ultraviolet ray to be irradiated is preferably in a wavelength range in which the photoreactive group of a polymer or monomer having a photoreactive group can absorb light energy. Specifically, ultraviolet rays in the wavelength range of 250 to 400 nm are particularly preferred. Examples of light sources used for 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 halide lamps. Is more preferable. Among these, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp are preferable because of their high luminous intensity of ultraviolet rays having a wavelength of 313 nm. Polarized ultraviolet rays can be irradiated by irradiating the light from the light source through a suitable polarizer. As such a polarizer, a polarizing filter, a polarizing prism such as Glen Thompson and Glenn Taylor, or a wire grid type polarizer can be used.

In addition, when performing rubbing or polarization irradiation, when masking is performed, a plurality of regions (patterns) having different directions of liquid crystal alignment may be formed.

The groove alignment film is a film having an uneven 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 the direction along the grooves.

As a method of obtaining the grooved alignment film, a method of forming an uneven pattern by developing and rinsing treatment after exposure through an exposure mask having a pattern-shaped slit on the surface of the photosensitive polyimide film, and a plate-shaped disc having grooves on the surface. E, a method of forming a layer of UV curing resin before curing, transferring the formed resin layer to a substrate, and then curing, and pressing a roll-shaped disc having a plurality of grooves on the film of the UV curing resin formed on the substrate before curing. A method of forming irregularities and hardening after that is mentioned.

The thickness of the alignment film (orientation film or photoalignment 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, and still more preferably 10 It is in the range of -200 nm, particularly preferably 50-150 nm.

The thickness of the polarizing plate of the present invention is preferably 10 to 300 µm, more preferably 20 to 200 µm, and still more preferably 25 to 100 µm from the viewpoint of flexibility and visibility of the display device.

Since the polarizing film and the polarizing plate of the present invention are excellent in polarization performance, they can be suitably used for various display devices. 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. As a display device, a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (electric field emission display device (FED, etc.)), Surface field emission display device (SED)), electronic paper (display device using electronic ink or electrophoretic element), plasma display device, projection type display device (grating light valve (GLV) display device, digital micro-mirror device (DMD)) Display devices, etc.), piezoelectric ceramic displays, and the like. In particular, an organic EL display device and a touch panel display device are preferred, and an organic EL display device is particularly preferred. A display device including the polarizing plate of the present invention can be obtained by bonding the polarizing plate of the present invention to the surface of a display device via an adhesive or an adhesive.

Example

Hereinafter, the present invention will be described in more detail by examples. "%" and "parts" in the examples are mass% and mass parts unless otherwise specified.

<Preparation of composition for photoalignment film formation>

A composition for forming a photoalignment film was obtained by mixing the following components described in JP 2013-033249 A and stirring the obtained mixture at 80°C for 1 hour.

Photoalignable polymer:

[Formula 14]

·Solvent:

o-xylene 98 copies

<Preparation of the photoalignment film base material>

Using a 100 mm × 100 mm triacetylcellulose film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.) as a substrate, after corona treatment was performed on the surface of the film, the composition for forming a photoalignment film was applied and dried at 120°C. A dry film was obtained. Polarized UV was irradiated on this dried film to form a photo-alignment film to obtain a film with a photo-alignment film. The polarized UV treatment was performed under conditions in which the intensity measured at a wavelength of 365 nm was 100 mJ using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Electric Corporation). In this way, a film with a photo-alignment film was prepared.

<Preparation of the composition for forming a polarizing film>

1. Comparative Example 1

The following component was mixed and stirred at 80 degreeC for 1 hour, and the composition for polarizing film formation (1) was obtained. As the dichroic dye, the azo dye described in Examples of JP 2013-101328 A was used.

Polymerizable liquid crystal compound (mixture):

[Formula 15]

[Formula 16]

Dichroic pigment:

[Formula 17]

[Formula 18]

[Formula 19]

·Polymerization initiator:

2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Chiba Specialty Chemicals Co., Ltd.) Part 6

·Leveling agent:

Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) 1.2 part

·Solvent:

toluene 400 copies

<Measurement of phase transition temperature>

(1) formation of alignment layer

The phase transition temperature of the polymerizable liquid crystal compound in the composition (1) for forming a polarizing film was measured according to the following method. On the glass substrate, a 2 mass% aqueous solution of polyvinyl alcohol (polyvinyl alcohol 1000 complete saponification type, manufactured by Wako Pure Chemical Industries, Ltd.) was applied by a spin coating method, and after drying, a film having a thickness of 100 nm was formed. Subsequently, an alignment film was formed by performing a rubbing treatment on the surface of the obtained film. The rubbing treatment was performed using a semi-automatic rubbing device (brand name: LQ-008 type, manufactured by Joyo Engineering Co., Ltd.), and using a cloth (brand name: YA-20-RW, manufactured by Yoshikawa Chemical Industries, Ltd.), with a press fit of 0.15 mm and rotation speed of 500 It implemented under the conditions of rpm and 16.7 mm/s.

(2) Measurement of phase transition temperature

75 parts by mass of a polymerizable liquid crystal compound (4-6) and 25 parts by mass of a polymerizable liquid crystal compound (4-8) were added to 400 parts by mass of chloroform and stirred at 80° C. for 1 hour to obtain a uniformly mixed mixed composition. The obtained composition was applied on a glass substrate on which the alignment film was formed by a spin coating method, and heated and dried on a hot plate at 130° C. for 3 minutes to remove chloroform as a solvent. Then, the obtained coating film was quickly cooled to room temperature to obtain a dry film of a polymerizable liquid crystal compound. The dried film was heated again to 130°C on a hot plate, and then observed with a polarizing microscope at a rate of 5°C/min to 23°C to measure the phase transition temperature. As a result, the phase transition to the nematic liquid crystal phase at 111.6° C., the phase transition to the Smectic A phase at 109.2° C., the phase transition to the Smectic B phase at 93.9° C., and maintaining the Smectic B phase until 23° C. Confirmed. In the above process, it was confirmed that the isotropic phase transition temperature was 111.6°C.

<Method of manufacturing a polarizing film>

(1) formation of a photoalignment film

After corona treatment was performed on the film surface using a triacetylcellulose film (KC8UX2M, manufactured by Konica Minolta Co., Ltd.) as a substrate, the composition for forming a photoalignment film was applied and dried at 120°C to obtain a dry film. Polarized UV was irradiated on this dried film to form a photo-alignment film to obtain a film with a photo-alignment film. The polarized UV treatment was performed under conditions in which the intensity measured at a wavelength of 365 nm was 100 mJ using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Electric Corporation).

(2) formation of polarizing film

On the film on which the photoalignment film obtained above was formed, the composition for polarizing film formation (1) was applied by a bar coating method (#9 30 mm/s). After the applied film was stopped still at 23°C for 30 seconds at room temperature, the solvent was sufficiently removed by heating and drying for 1 minute in a drying oven at 120°C, and the polymerizable liquid crystal compound was phase-transferred to the isotropic liquid crystal phase, and then cooled to room temperature. And the polymerizable liquid crystal compound was subjected to a phase transition to a smectic liquid crystal state. Subsequently, using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Electric Corporation), ultraviolet rays having an exposure amount of 1000 mJ/cm 2 (based on 365 nm) are irradiated to the layer formed of the composition for forming a polarizing film, and the dried film The polymerizable liquid crystal compound contained in was polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film 1 was formed from the dried film. The film thickness of this polarizing film 1 was measured with a laser microscope (OLS3000 manufactured by Olympus), and it was 2.3 µm. What was obtained in this way is a polarizer (polarizing film laminated body) containing a polarizing film and a base material. For this polarizing film (1), as a result of performing X-ray diffraction measurement in the same manner using an X-ray diffraction apparatus X'Pert PRO MPD (manufactured by Spectres Co., Ltd.), the peak half width (FWHM) = around 2θ = 20.2° A sharp diffraction peak (Bragg peak) of about 0.17° is obtained. Moreover, the same result was obtained even in the incident from the rubbing vertical direction. The order period (d) obtained from the peak position was about 4.4 Å, and it was confirmed that a structure reflecting the high-order smectic phase was formed.

<Evaluation of dot defect>

As a result of transmitting and observing the thus-obtained polarizing film 1 with a microscope at 200 times, color loss of about 200 to 800 µm was observed on the entire surface. In addition, as a result of observing the absorption axis (molecular alignment direction) of the polarizing film to be 45° under a 200-fold polarization microscope CrossNichol, it was confirmed that the polymerizable liquid crystal compound itself was oriented because light leakage occurred. From the above observation result, it was confirmed that a region (dot defect) in which the dichroic dye was not contained in the liquid crystal domain was generated.

<dot defect evaluation criteria>

○: It was not confirmed visually, and it was not confirmed also in the said microscopic observation.

?: It was not confirmed with the naked eye, but was confirmed in the microscopic observation.

X: It was visually confirmed, and it was also confirmed in the said microscopic observation.

<Measurement of polarization Py and single transmittance Ty>

In the following manner, the polarization degree Py and the single transmittance Ty of the polarizing film laminate of Comparative Example 1 were measured. A device in which a folder with a polarizer attached to a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation) was measured for the transmittance (Ta1) in the transmission axis direction and the transmittance in the absorption axis direction (Tb2) in the wavelength range of 380 nm to 780 nm. And measured by the double beam method. A mesh for cutting the amount of light by 50% was provided on the reference side of the folder.

Using the following equations (Equation 1) and (Equation 2), the single transmittance and polarization degree at each wavelength were calculated, and luminous intensity was corrected according to the second degree field of view (C light source) of JIS Z 8701 to correct the luminous intensity. The single transmittance (Ty) and the luminous sensitivity corrected polarization degree (Py) were calculated. As a result, the high performance derived from the smectic liquid crystal highly oriented at Ty = 42.5% and Py = 97.6% was exhibited (this value corresponds to 48 in the absorption dichroic ratio).

Single transmittance Ty (%) = (Ta1 + Tb2)/2 (Equation 1)

Polarization Py (%) = (Ta1-Tb2)/(Ta1 + Tb2) × 100 (Equation 2)

2. Comparative Examples 2 to 5, Examples 1 to 16

Except having changed the solvent to the composition shown in Table 1, it carried out similarly to Comparative Example 1, and produced the composition for polarizing film formation (2)-(21), and it carried out similarly to Comparative Example 1, and polarizing film (2)-(21) Was prepared. The dot defect, the polarization degree Py, and the single transmittance Ty of the obtained polarizing film were measured in the same manner as in Comparative Example 1. Table 2 shows the evaluation results.

3. Example 17

Except having changed the polymerizable liquid crystal compound to the following polymerizable liquid crystal compound, it carried out similarly to Comparative Example 1, and produced the composition for polarizing film formation 22, and it carried out similarly to Comparative Example 1, and produced the polarizing film 22. Further, in the same manner as in Comparative Example 1, as a result of measuring the phase transition temperature of the polymerizable liquid crystal compound used in Example 17, the phase transition was performed at 105.6°C to the nematic liquid crystal phase, and the phase transition was performed at 102.1°C to the Smectic A phase, and 85.4 It was confirmed that the phase shifted to the Smectic B phase at °C, and maintained the Smectic B phase until it reached 23 °C. In the above process, it was confirmed that the isotropic phase transition temperature was 105.6 °C. The dot defect, the polarization degree Py, and the single transmittance Ty of the obtained polarizing film were measured in the same manner as in Comparative Example 1. Table 2 shows the evaluation results.

[Formula 20]

[Formula 21]

4. Reference example

Except having replaced the polymerizable liquid crystal compound with the nematic liquid crystal Pario Color LC242 (manufactured by BASF), a polarizing film-forming composition (23) was prepared in the same manner as in Comparative Example 1, and the polarizing film ( 23) was prepared. The dot defect, the polarization degree Py, and the single transmittance Ty of the obtained polarizing film were measured in the same manner as in Comparative Example 1. In addition, the isotropic phase transition temperature of LC242 is 118.0°C. Table 2 shows the evaluation results.

According to the present invention, the organic solvent A having a boiling point higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound -20 °C to 50 °C, and having a boiling point higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound 50 °C It can be seen that the polarizing film formed from the composition for forming a polarizing film containing the organic solvent B has no dot defects and has high polarization performance.

Claims (14)

A polymerizable liquid crystal compound exhibiting smectic liquid crystal properties, a dichroic dye, and at least two organic solvents, wherein the organic solvent is -20°C or more and 50°C or less higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound. A composition for forming a polarizing film comprising an organic solvent A having a boiling point and an organic solvent B having a boiling point higher than 50° C. than the isotropic phase transition temperature of the polymerizable liquid crystal compound. The method of claim 1,
The composition for forming a polarizing film, wherein the content of the organic solvent A is 51 to 99 parts by mass, and the content of the organic solvent B is 1 to 49 parts by mass with respect to 100 parts by mass of the total organic solvent contained in the composition for forming a polarizing film. The method according to claim 1 or 2,
The boiling point of organic solvent A is 0°C or more and 50°C or less higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound, and the boiling point of organic solvent B exceeds 50°C and 150°C or less than the isotropic phase transition temperature of the polymerizable liquid crystal compound High, a composition for forming a polarizing film. The method according to any one of claims 1 to 3,
Further comprising a polymerization initiator, the composition for forming a polarizing film. The method according to any one of claims 1 to 4,
The composition for forming a polarizing film, wherein the organic solvent A is a ketone solvent or an aromatic solvent. The method according to any one of claims 1 to 5,
The composition for forming a polarizing film, wherein the organic solvent B is selected from the group consisting of a glycol-based solvent, a ketone-based solvent, and an amide-based solvent. The method according to any one of claims 1 to 6,
The composition for forming a polarizing film, wherein the solid content of the composition for forming a polarizing film is 5 to 40% by mass. The method of claim 7,
The composition for forming a polarizing film, wherein the proportion of the polymerizable liquid crystal compound in the solid content is 40 to 99.9% by mass. The method according to claim 7 or 8,
The composition for forming a polarizing film, wherein the ratio of the dichroic dye in the solid content is 1 to 20% by mass. As a cured product of the composition for forming a polarizing film according to any one of claims 1 to 9, a polymerizable liquid crystal compound and/or a polymer thereof are aligned in a smectic liquid crystal state. The method of claim 10,
A polarizing film from which a Bragg peak is obtained in X-ray diffraction measurement. A polarizing plate comprising the polarizing film, the substrate, and the alignment film according to claim 10 or 11. Forming a coating film of the composition for forming a polarizing film according to any one of claims 1 to 9,
The coating film is heated and dried to a temperature equal to or higher than the isotropic phase transition temperature of the polymerizable liquid crystal compound contained in the composition for forming a polarizing film, and then lowered, thereby causing the polymerizable liquid crystal compound to phase transition to the smectic liquid crystal phase
A method of manufacturing a polarizing plate comprising forming a polarizing film by polymerizing a polymerizable liquid crystal compound while maintaining the smectic liquid crystal phase. As the manufacturing method of the polarizing plate according to claim 13, wherein the coating film of the composition for forming a polarizing film is formed on the photo-alignment film, the photo-alignment film,
Forming a coating film from a composition containing a polymer or a monomer and a solvent that generates an orientation regulating force by light,
Drying off the solvent from the coating film to obtain a dry coating film, and
A method for producing a polarizing plate, which is formed by a method comprising irradiating polarized ultraviolet rays to the dried coating film.