KR102190830B1 - Polarizing film, circular polarizing plate and organic el image display device using the same - Google Patents

Abstract

[Problem] To provide a polarizing film having high polarization performance while being a thin film useful for a member for a display device.
[Solution] As a polarizing film formed from a composition containing two or more dichroic dyes different at a maximum absorption wavelength,
Has one orientation direction,
The following formulas (I) to (V)
0.3≤A450/A550<0.8 (I)
0.3≤A450/A650<1.0 (II)
0.5≤A450≤2 (III)
1≤A550≤3 (IV)
1≤A650≤3 (V)
(In the meal,
A450 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 450 nm,
A550 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 550 nm,
A650 denotes the absorbance of polarized light parallel to the orientation direction at a wavelength of 650 nm.)
A polarizing film having an absorption spectrum that satisfies all of the relationships represented by.

Description

Polarizing film, circular polarizing plate, and organic EL image display device using these TECHNICAL FIELD {POLARIZING FILM, CIRCULAR POLARIZING PLATE AND ORGANIC EL IMAGE DISPLAY DEVICE USING THE SAME}

The present invention relates to a polarizing film, a circularly polarizing plate, and an organic EL image display device using the same.

In an organic EL image display device, a circularly polarizing plate is used to prevent reflection of external light in a bright place. As such a circularly polarizing plate, it is known to include, for example, a polarizing film (iodine-PVA polarizing film) in which PVA (polyvinyl alcohol) is dyed with iodine (see, for example, Patent Document 1).

Patent Document 1: Japanese Patent Application Laid-Open No. Hei 7-142170

However, in a conventional organic EL image display device provided with a circularly polarizing plate including a polarizing film, there is a problem that the polarizing film absorbs light from the organic EL light emitting element about half of the amount of light. For this reason, it is necessary to increase the light emission intensity of the organic EL light emitting element, which leads to a shorter life of the organic EL image display device. Particularly, blue light with a short lifetime (light-emitting element having a wavelength of 450 nm) was markedly deteriorated over time. However, a circularly polarizing plate and a polarizing film capable of solving the above problem have not been realized at all.

The present invention includes the following inventions.

[1] It is formed of a composition containing two or more dichroic dyes different in the maximum absorption wavelength (hereinafter, referred to as "a composition for forming a polarizing film" in some cases), and

Has one orientation direction,

The following formulas (I) to (V)

0.3≤A450/A550<0.8 (I)

0.3≤A450/A650<1.0 (II)

0.5≤A450≤2 (III)

1≤A550≤3 (IV)

1≤A650≤3 (V)

(In the formula,

A450 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 450 nm,

A550 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 550 nm,

A650 represents the absorbance of polarized light parallel to the orientation direction at a wavelength of 650 nm.)

A polarizing film having an absorption spectrum that satisfies all of the relationships represented by (hereinafter, referred to as "this polarizing film" in some cases).

[2] The polarizing film according to [1], wherein the composition further contains a polymerizable smectic liquid crystal compound.

[3] The polarizing film according to [1] or [2], wherein both of the two or more dichroic dyes are polyazo dyes represented by the following formula (1).

[In equation (1),

n is 1 or 2.

Ar ₁ and Ar ₃ each independently represent any one of the following groups.

Ar ₂ represents any of the following groups.

A ₁ and A ₂ each independently represent any one of the following groups.

m is an integer from 0 to 10, and when there are two m in the same air, the two m are the same or different from each other.]

[4] The polarizing film according to any one of [1] to [3], wherein the luminous sensitivity correcting single transmittance (Ty) is 43% or more, and the luminous intensity correcting single polarization degree (Py) is 90% or more.

[5] having a polarizing film and a λ/4 layer according to any one of [1] to [4],

A circularly polarizing plate satisfying the following requirements (A1) and (A2) (hereinafter, referred to as "this circularly polarizing plate" in some cases).

(A1) the angle formed by the absorption axis of the polarizing film and the slow axis of the λ/4 layer is approximately 45°;

(A2) The value of the frontal retardation of the λ/4 layer measured with light having a wavelength of 550 nm is in the range of 100 nm to 150 nm

[6] The circularly polarizing plate according to the above [5], having a property that the value of the front retardation of the λ/4 layer for visible light decreases as the wavelength decreases.

[7] A polarizing film according to any one of [1] to [4] above, and a λ/2 layer and a λ/4 layer in this order,

Circular polarizing plate satisfying the following requirements (B1) to (B4).

(B1) the angle formed by the absorption axis of the polarizing film and the slow axis of the λ/2 layer is approximately 15°;

(B2) the angle between the slow axis of the λ/2 layer and the slow axis of the λ/4 layer is approximately 60°;

(B3) the λ/2 layer has a front retardation value of the λ/4 layer measured with light having a wavelength of 550 nm in the range of 200 nm to 300 nm;

(B4) The λ/4 layer has a front retardation value in the range of 100 nm to 150 nm measured with light having a wavelength of 550 nm.

[8] An organic EL display device comprising the circularly polarizing plate according to any one of [5] to [7] and an organic EL element (hereinafter, referred to as "this organic EL display device" in some cases).

[9] Of the light emitted from the light-emitting layer, when the intensity of light having a wavelength of 450 nm is set to I450, the intensity of light having a wavelength of 550 nm is set to I550, and the intensity of light having a wavelength of 650 nm is set to I650,

1≤I450/I550<2 (X)

1≤I450/I650<2 (XI)

The organic EL display device according to the above [8], which has an emission spectrum that satisfies all of the relationships represented by.

According to this polarizing film, when used in an organic EL image display device, it is possible to provide a circularly polarizing plate (this circularly polarizing plate) in which absorption of light from an organic EL light-emitting element, in particular, light in the vicinity of 450 nm in wavelength is reduced.

1 is a cross-sectional view schematically showing an embodiment of a method for continuously manufacturing this polarizing film.
Fig. 2 is a projection diagram schematically showing an angle formed by an absorption axis of the present polarizing film and a slow axis of a λ/4 layer in one embodiment of the circularly polarizing plate.
3 is a cross-sectional view schematically showing an embodiment of a method for continuously manufacturing this polarizing film.
4 is a cross-sectional view schematically showing the configuration of the organic EL display device.
5 is a cross-sectional view schematically showing a layer sequence of a portion C of the organic EL display device 30;
6 is a cross-sectional view schematically showing the configuration of the organic EL display device.

This polarizing film can realize the present organic EL display device having a high lifespan by using the present circularly polarizing plate including the present polarizing film described later.

A450/A550 in formula (I) is more preferable if it satisfies the relationship of 0.5≦A450/A550<0.8.

A450/A650 in Formula (II) is more preferable if it satisfies the relationship of 0.5≦A450/A650<0.8.

A450 in formula (III) is more preferable if the relationship of 0.5≦A450≦1.6 is satisfied, and A550 in formula (IV) is more preferable if the relationship of 1.0≦A550≦2.0 is satisfied, and in formula (V) A650 is more preferable if it satisfies the relationship of 1.0≦A650≦2.0.

In the drawings attached to this specification, dimensions are arbitrary for easy viewing.

<Two-color pigment>

The composition for forming a polarizing film contains two or more dichroic dyes that are different in the maximum absorption wavelength. The dichroic dye refers to 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 may be a dye or a pigment. Multiple types of this dye may be used, a plurality of pigments may be used, or a combination of a dye and a pigment may be used.

It is preferable that the dichroic dye has a maximum absorption wavelength (λMAX) in the range of 300 nm to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among them, the dichroic dye is preferably an azo dye. Examples of the azo dye include a monoazo dye, a bis azo dye, a tris azo dye, a tetrakis azo dye, and a stilbenazo dye, and preferably a bis azo dye and a tris azo dye.

The dichroic dye is particularly preferably one represented by formula (1) (hereinafter, referred to as “azo dye (1)” in some cases). It is more preferable that the azo dye 1 exhibits a maximum absorption wavelength (λ MAX) in the range of 300 nm to 700 nm.

It is preferable that the positional isomerism of the azobenzene moiety of the azo dye (1) is trans.

Examples of the azo dye (1) include compounds each represented by formulas (1-1) to (1-28).

Among the specific examples of the azo dye (1), formula (1-2), formula (1-5), formula (1-6), formula (1-8), formula (1-10), formula (1-12 ), equation (1-13), equation (1-15), equation (1-16), equation (1-19), equation (1-20), equation (1-21), equation (1-22) , More preferably each represented by formula (1-23), formula (1-24) and formula (1-26), and formula (1-2), formula (1-5), and formula (1-8) , Formula (1-10), Formula (1-15), Formula (1-21), Formula (1-22) What is represented by Formula (1-26) is especially preferable.

As an anthraquinone dye, a compound represented by formula (1-28) is preferable.

[In formula (1-28),

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.]

As the acridine dye, a compound represented by formula (1-29) is preferable.

[In formula (1-29),

*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 oxazone dye, a compound represented by formula (1-30) is preferable.

[In formula (1-30),

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 the above formulas (1-28), formulas (1-29) and (1-30), the alkyl group having 1 to 6 carbon atoms of R ^x is a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, etc. 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 (1-31) and a compound represented by formula (1-32) are preferred.

[In formula (1-31),

D ¹ and D ² each independently represent a group represented by any one of formulas (1-31a) to (1-31d).

n5 represents the integer of 1-3.]

[In formula (1-32),

D ³ and D ⁴ each independently represent a group represented by any one of formulas (1-32a) to (1-32h).

n6 represents an integer of 1 to 3.]

Although two or more types of dichroic dyes are contained in the composition for forming a polarizing film, it is more preferable if it contains two to three kinds of dichroic dyes, and even more preferably if it contains two to three kinds of azo dyes (1). Do. Among these combinations of 2 to 3 types of azo dyes (1) [indicated by the names “first dye”, “second dye” and “third dye”), a suitable combination is shown.

[Table 1]

[Table 2]

According to the composition for forming a polarizing film containing the combination of the azo dye (1) shown in the table above, absorption satisfying all the relationships represented by formulas (I) to (V) by the method for producing a polarizing film described later This polarizing film having a spectrum becomes easy to obtain.

In addition, notation in the table corresponds to the code|symbol of the specific example of the azo dye (1), and "1-5" means "azo dye (1) represented by formula (1-5)", for example.

The content of the dichroic dye in the composition for forming a polarizing film is preferably 1 part by mass or more and 90 parts by mass or less, more preferably 1 part by mass or more and 50 parts by mass or less with respect to the total 100 parts by mass of the composition for forming a polarizing film. It is preferable, and 3 mass parts or more and 10 mass parts or less are more preferable.

The content of the dichroic dye in the composition for forming a polarizing film is preferably 0.1 parts by mass or more and 50 parts by mass or less, and 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the total of the polymerizable liquid crystal compounds described later. It is more preferable, and 0.1 mass parts or more and 10 mass parts or less are still more preferable. When the content of the dichroic dye is within this range, the polymerizable liquid crystal compound can be polymerized without disturbing the orientation of the polymerizable liquid crystal compound.

<Polymerizable liquid crystal compound>

Since a polarizing film of practical strength is obtained, the composition for forming a polarizing film preferably contains a polymerizable liquid crystal compound. A polymerizable liquid crystal compound is a compound having a polymerizable group and showing a liquid crystal state. The polymerizable group means a group involved in the polymerization reaction of the polymerizable liquid crystal compound.

As a polymerizable liquid crystal compound, a polymerizable nematic liquid crystal compound and a polymerizable smectic liquid crystal compound are mentioned, and a polymerizable smectic liquid crystal compound is preferable from a viewpoint of polarization performance.

The liquid crystal state exhibited by the polymerizable smectic liquid crystal compound is more preferably a high-order smectic phase. The high-order Smectic phase here refers to Smectic B, Smectic D, Smectic E, Smectic F, Smectic G, Smectic H, Smectic I, Smectic J, Smectic It is a Smectic K phase and a Smectic L phase, and among them, Smectic B phase, Smectic F phase, and Smectic I phase are more preferable.

The present polarizing film with high alignment order can be obtained by the liquid crystal state exhibited by the polymerizable smectic liquid crystal compound. In addition, this polarizing film having such a high degree of alignment has a black peak obtained by X-ray reflection measurement.

The black peak is a peak derived from the plane periodic structure of molecular orientation, and according to the composition for forming a polarizing film, the present polarizing film having a periodic interval of 3.0 Å to 5.0 Å can be obtained.

As a preferable polymerizable smectic liquid crystal compound, a compound represented by Formula (2) (hereinafter, sometimes referred to as "compound (2)") is mentioned.

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

[In equation (2),

X ¹ , X ² and X ³ each independently represent a p-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. However, at least one of X ¹ , X ² and X ³ is a p-phenylene group which may have a substituent.

Y ¹ and Y ² are, independently of each other, -CH ₂ CH ₂ -, -CH ₂ O-, -COO-, -OCOO-, single bond, -N=N-, -CR ^a =CR ^b -,- C≡C- or -CR ^a =N-. R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

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

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-, -S- or -NH- It may be substituted with.]

At least one of X ¹ , X ² and X ³ is a 1,4-phenylene group which may have a substituent, but two or more of these are preferably p-phenylene groups which may have a substituent.

It is preferable that the p-phenylene group is unsubstituted. It is preferable that the cyclohexane-1,4-diyl group is a trans-cyclohexane-1,4-diyl group, and it is more preferable that this trans-cyclohexane-1,4-diyl group is also unsubstituted.

Examples of the substituents that the p-phenylene group or the cyclohexane-1,4-diyl group have optionally include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group and butyl group; Cyano group; A halogen atom and the like. Further, -CH ₂ -constituting the cyclohexane-1,4-diyl group may be substituted with -O-, -S-, or -NR-. R is a C1-C6 alkyl group or a phenyl group.

Y ¹ is preferably -CH ₂ CH ₂ -, -COO- or a single bond, and Y ² is preferably -CH ₂ CH ₂ -or -CH ₂ O-.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. That is, U ¹ and U ² are preferably both polymerizable groups, and both are preferably photopolymerizable groups. The photopolymerizable group refers to a group capable of participating in the polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. When a polymerizable Smectic liquid crystal compound having a photopolymerizable group is used, it is also advantageous in that the polymerizable Smectic liquid crystal compound can be polymerized under a lower temperature condition.

The polymerizable groups of U ¹ and U ² may be different from each other, but the same kind of group is preferable. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group and the like. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. That U ¹ and U ² are the same kind of polymerizable group means, for example, when both U ¹ and U ² are acryloyloxy groups.

Examples of the alkanediyl group of 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 eco Acid-1,20-diyl group, etc. are mentioned. V ¹ and V ² are preferably an alkanediyl group having ² to 12 carbon atoms, 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 unsubstituted and linear alkanediyl group.

W ¹ and W ² are each independently a single bond or -O-.

Examples of the compound (2) include compounds each represented by formulas (2-1) to (2-24). When a specific example of compound (2) has a cyclohexane-1,4-diyl group, it is preferable that the cyclohexane-1,4-diyl group is a trans chain.

The polymerizable smectic liquid crystal compound can be used alone or in a mixture of two or more for forming a polarizing film. Further, two or more kinds of polymerizable Smectic liquid crystal compounds may be used, and one or more of these two or more kinds of polymerizable Smectic liquid crystal compounds may be compound (2).

When a polymerizable Smectic liquid crystal compound is used in the composition for forming a polarizing film, the phase transition temperature of the polymerizable Smectic liquid crystal compound is determined in advance, and polarization is performed so that the polymerizable Smectic liquid crystal compound polymerizes under a temperature condition below the phase transition temperature. Components other than the polymerizable smectic liquid crystal compound of the film-forming composition are adjusted. As a component capable of controlling such a polymerization temperature, a photoinitiator, a photosensitizer, a polymerization inhibitor, and the like described later can be mentioned. By appropriately controlling these types and amounts, the polymerization temperature of the polymerizable smectic liquid crystal compound can be controlled. In addition, even when a mixture of two or more polymerizable smectic liquid crystal compounds is used for the composition for forming a polarizing film, after obtaining the phase transition temperature of the mixture of two or more polymerizable smectic liquid crystal compounds, the polymerization temperature Control.

Among compound (2), formula (2-2), formula (2-3), formula (2-4), formula (2-6), formula (2-7), formula (2-8), formula ( 2-13), formula (2-14), formula (2-15), and one or more selected from the group consisting of each represented by formula (2-24) is preferred.

The polymerizable smectic liquid crystal compound sufficiently maintains the liquid crystal state of the high-order smectic phase under temperature conditions that are easily below the phase transition temperature by mixing two or more types or by interaction with a polymerization initiator used together. One can be polymerized. More specifically, the polymerizable smectic liquid crystal compound can be polymerized while sufficiently maintaining the liquid crystal state of the high-order smectic phase under a temperature condition of 70°C or less, preferably 60°C or less by interaction with a polymerization initiator. It is preferably a compound capable of.

The polymerizable smectic liquid crystal compound contained in the composition for forming a polarizing film may be a single type or a plurality of types (two or more types), but is preferably a plurality of types.

When using the composition for forming a polarizing film containing a polymerizable smectic liquid crystal compound, the content ratio of the polymerizable smectic liquid crystal compound is preferably 70% by mass to 99.9% by mass with respect to the solid content of the composition for forming a polarizing film, It is more preferably 90% by mass to 99.9% by mass. When the content ratio of the polymerizable smectic liquid crystal compound is within the above range, the orientation of the polymerizable smectic liquid crystal compound tends to increase. Here, the solid content means the total amount of components excluding volatile components such as a solvent from the composition for forming a polarizing film. In addition, when a plurality of types of polymerizable smectic liquid crystal compounds are contained in the composition for forming a polarizing film, the total content ratio may be within the above-described range.

<solvent>

The composition for forming a polarizing film may contain a solvent. In general, since the viscosity of the polymerizable smectic liquid crystal compound is high, the application becomes easy by including a solvent, and as a result, the formation of a polarizing film is often easier. As the solvent, a solvent capable of dissolving a polymerizable smectic liquid crystal compound and a dichroic dye is preferable. Moreover, it is preferable that it is a solvent inert to the polymerization reaction of the composition for polarizing film formation.

Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone or propylene glycol methyl ether acetate, and ethyl lactate; Ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone; Aliphatic hydrocarbon solvents such as pentane, hexane and heptane; Aromatic hydrocarbon solvents such as toluene and xylene (xylene may be any of an o-form, m-form and p-form, and may be a mixture of two or more selected from them), and nitrile solvents such as acetonitrile; Ether solvents such as tetrahydrofuran and dimethoxyethane; And chlorine-containing solvents such as chloroform and chlorobenzene. These solvents may be used alone or in combination of multiple types.

The content of the solvent is preferably 50% by mass to 98% by mass with respect to the total amount of the composition for forming a polarizing film. In other words, the solid content in the composition for forming a polarizing film is preferably 2% by mass to 50% by mass. When the solid content is 2% by mass or more, the thin polarizing film tends to be easily obtained. On the other hand, when the solid content is 50% by mass or less, since the viscosity of the composition for forming a polarizing film is lowered, the thickness of the polarizing film becomes substantially uniform, so that there is a tendency that it is difficult to generate unevenness in this polarizing film. In addition, such solid content can be determined so that a desired thickness of the polarizing film described later can be formed.

<Preparation of polymerization reaction>

It is preferable if the composition for polarizing film formation contains a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of a polymerizable smectic liquid crystal compound, and a photoinitiator is preferable because a polymerization reaction can be started under a lower temperature condition. Specifically, a compound capable of generating an active radical or an acid by the action of light is used as a photopolymerization initiator. Among the photoinitiators, it is more preferable to generate radicals by the action of light.

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

As a benzoin compound, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. are mentioned, for example.

As a benzophenone compound, for example, benzophenone, o-benzoyl methylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide, 3,3',4,4'-tetra(tert-butylper Oxycarbonyl)benzophenone and 2,4,6-trimethylbenzophenone, and the like.

Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, and 2-benzyl-2-dimethylamino-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-[ Oligomers of 4-(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, for example, 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-tri Ajin, etc. are mentioned.

As a polymerization initiator, what is readily available in the market can be used. As commercially available photopolymerization initiators, "Irgacure 907", "Irgacure 184", "Irgacure 651", "Irgacure 819", "Irgacure 250", "Irgacure 369" (Chiba Japan Co., Ltd.); "Seikuol BZ", "Seikuol Z", "Seikuol BEE" (Seiko Chemical Co., Ltd.); "Kayacure BP100" (Nihon Kayaku Co., Ltd.); "Kayacure-UVI-6992" (manufactured by Dow Corporation); "Adeka Optoma SP-152", "Adeka Optoma SP-170" (ADEKA Co., Ltd.); "TAZ-A", "TAZ-PP" (Japan Siebel Hegner Corporation); And "TAZ-104" (Sanwa Chemical), and the like.

When the composition for forming a polarizing film contains a polymerization initiator, the content can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound (polymerizable Smectic liquid crystal compound) contained in the composition for forming a polarizing film. For example, the content of the polymerization initiator per 100 parts by mass of the polymerizable liquid crystal compound (polymerizable Smectic liquid crystal compound) is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass. Do. If the content of the polymerizable initiator is within this range, polymerization can be performed without disturbing the orientation of the polymerizable smectic liquid crystal compound, so that the polymerizable smectic liquid crystal compound can be polymerized while maintaining the liquid crystal state of the higher order smectic phase. I can.

When the composition for forming a polarizing film contains a polymerization initiator, the composition for forming a polarizing film may contain a sensitizer. As a sensitizer, a photosensitizer is preferable. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (for example, 2,4-diethyl thioxanthone, 2-isopropyl thioxanthone, etc.); Anthracene compounds such as anthracene and alkoxy group-containing anthracene (eg, dibutoxyanthracene); Phenothiazine, rubrene, and the like.

When the composition for forming a polarizing film contains a polymerization initiator and a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) contained in the composition for forming a polarizing film can be further promoted. The amount of the sensitizer used can be appropriately adjusted according to the type and amount of the polymerization initiator and the polymerizable smectic liquid crystal compound to be used in combination, but for example, 0.1 to 30 parts by mass per 100 parts by mass of the total amount of the polymerizable smectic liquid crystal compound It is preferable, and 0.5-10 mass parts is more preferable, and 0.5-8 mass parts is still more preferable.

It has been described that the polymerization reaction of the polymerizable liquid crystal compound (polymerizable Smectic liquid crystal compound) can be accelerated by containing a sensitizer in the composition for forming a polarizing film, but in order to stably proceed the polymerization reaction, the formation of a polarizing film A polymerization inhibitor may be suitably contained in the solvent composition. By containing the polymerization inhibitor, the degree of progress of the polymerization reaction of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) can be controlled.

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

When a polymerization inhibitor is contained in the composition for forming a polarizing film, its content can be appropriately adjusted depending on the kind and amount of the polymerizable smectic liquid crystal compound to be used, the amount of the sensitizer used, etc., but, for example, a polymerizable liquid crystal compound ( The content of the polymerization inhibitor per 100 parts by mass of the polymerizable smectic liquid crystal compound) is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 0.5 to 8 parts by mass. When the content of the polymerization inhibitor is within this range, since the orientation of the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound) contained in the composition for forming a polarizing film can be polymerized without disturbing the polymerizable liquid crystal compound (polymerization The Smectic liquid crystal compound) can further be polymerized while maintaining a satisfactory liquid crystal state of a higher order Smectic phase.

<Leveling agent>

It is preferable that the composition for forming a polarizing film contains a leveling agent. 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 applying the composition for forming a polarizing film more flat, and examples thereof include surfactants. The leveling agent is more preferably at least one selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component.

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 company], etc. are mentioned.

As a leveling agent mainly containing a fluorine atom-containing compound, "Megapak R-08", copper "R-30", copper "R-90", copper "F-410", copper "F-411", copper " F-443", "F-445", "F-470", "F-471", "F-477", "F-479", "F-482" and "F" -483" [DIC Corporation]; "Supron S-381", East "S-382", East "S-383", East "S-393", East "SC-101", East "SC-105", "KH-40" and " SA-100" [AGC Semichemical Co., Ltd.]; "E1830", "E5844" [Daikin Fine Chemical Research Institute]; "F-Top EF301", "EF303", "EF351", and "EF352" [Mitsubishi Material Denshi Kasei Co., Ltd.] and the like are mentioned.

When the composition for forming a polarizing film contains a leveling agent, the content is preferably 0.3 parts by mass or more and 5 parts by mass or less, and 0.5 parts by mass per 100 parts by mass of the polymerizable liquid crystal compound (polymerizable Smectic liquid crystal compound). More preferably more than 3 parts by mass or less. When the content of the leveling agent is within the above-described range, it is easy to horizontally align the polymerizable liquid crystal compound (polymerizable smectic liquid crystal compound), and the obtained polarizing film tends to become smoother. When the content of the leveling agent in the polymerizable smectic liquid crystal compound exceeds the above range, there is a tendency that unevenness is likely to occur in the resulting polarizing film. Moreover, the composition for polarizing film formation may contain two or more types of leveling agents.

<Method of forming this polarizing film>

Next, a method of forming the polarizing film viewed from the composition for forming a polarizing film will be described. In such a method, it is preferable to form the present polarizing film by applying the composition for forming a polarizing film on a substrate, preferably on a transparent substrate.

<Transparent substrate>

The transparent substrate is a substrate having a degree of transparency capable of transmitting light, particularly visible light. Transparency refers to a characteristic in which the transmittance of light having a wavelength of 380 nm to 780 nm is 80% or more. Specifically, when a transparent substrate is illustrated, a glass substrate, a plastic translucent sheet, and a translucent film are mentioned. In addition, examples of the plastics constituting the light-transmitting sheet and the light-transmitting film include polyolefins such as polyethylene, polypropylene and norbornene-based polymer; Cyclic olefin resin; 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 plastics such as polyphenylene sulfide and polyphenylene oxide. Among the specific examples of the transparent substrate, in view of a preferable plastic translucent sheet and a translucent film, a plastic translucent film, that is, a polymer film is preferable. Among the polymer films, polymer films made of cellulose esters, cyclic olefin resins, polyethylene terephthalate or polymethacrylic acid esters are particularly preferred from the viewpoint of being readily available on the market or having excellent transparency. In the production of the present polarizing film using a transparent substrate, a support substrate, etc., may be adhered to the transparent substrate because it can be easily handled without causing damage such as tearing when transporting or storing the transparent substrate. . In addition, although mentioned later, when manufacturing a circularly polarizing plate from this polarizing film, the retardation property may be provided to a transparent substrate. In this case, a polymer film may be prepared as a transparent substrate, and the polymer film may be subjected to a stretching treatment or the like to impart retardation to the polymer film to obtain a retardation film, and then the retardation film may be used as a transparent substrate. In addition, a method of imparting retardation to the transparent substrate (polymer film) will be described later.

Among polymer films, films made of cellulose esters, polycarbonates or cyclic olefin resins (cellulose ester films, polycarbonate films, cyclic olefin resin films) from the viewpoint of being easy to control the phase difference values when imparting retardation properties. ) Is preferred. Hereinafter, these three types of polymer films will be described in detail.

As for the cellulose ester constituting the cellulose ester film, at least a part of the hydroxyl groups contained in the cellulose are acetic acid esterified. A cellulose ester film made of such a cellulose ester can be easily obtained from the market. Examples of commercially available triacetylcellulose films include "Fuji Tag Film" (Fuji Shashin Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minoltaopt Co., Ltd.), and the like. Such a commercially available triacetylcellulose film can be used as it is or as a transparent substrate after imparting retardation as necessary. Further, the surface of the prepared transparent substrate may be subjected to surface treatment such as antiglare treatment, hard coat treatment, antistatic treatment or antireflection treatment, and then used as a transparent substrate.

In order to impart retardation to the polymer film, as described above, the polymer film is stretched or the like. Any polymer film made of plastic, that is, a thermoplastic resin, can be stretched, but a cyclic olefin resin film is preferable from the viewpoint of being easy to control the retardation. The cyclic olefin resin constituting the cyclic olefin resin film is composed of, for example, a polymer or copolymer (cyclic olefin resin) of cyclic olefins such as norbornene and polycyclic norbornene-based monomers, and the cyclic olefin resin is partially And may include an opening part. Further, a cyclic olefin resin containing a ring opening portion may be hydrogenated. In addition, this cyclic olefin resin may be a copolymer of, for example, a cyclic olefin and a chain olefin or a vinylated aromatic compound (such as styrene) from the viewpoint of not significantly impairing transparency or not significantly increasing hygroscopicity. In addition, the cyclic olefin resin may have a polar group introduced into its molecule.

When the cyclic olefin resin is a copolymer of a cyclic olefin and a chain olefin or an aromatic compound having a vinyl group, the chain olefin is ethylene or propylene, and as the vinylated aromatic compound, styrene, α-methylstyrene, and alkyl substituted Styrene, etc. In such a copolymer, the content ratio of the structural unit derived from the cyclic olefin is in the range of 50 mol% or less, such as about 15 mol% to 50 mol%, based on the total structural units of the cyclic olefin resin. When the cyclic olefin resin is a ternary copolymer obtained from a cyclic olefin, a chain olefin, and a vinylated aromatic compound, for example, the content ratio of the structural units derived from the chain olefin is 5 mol% with respect to the total structural units of the cyclic olefin resin. It is about -80 mol%, and the content ratio of the structural unit derived from a vinylated aromatic compound is about 5 mol%-80 mol%. The cyclic olefin resin of such a ternary copolymer has an advantage of being able to relatively reduce the amount of expensive cyclic olefin used when producing a cyclic olefin resin.

Cyclic olefin resins from which a cyclic olefin resin film can be produced can be easily obtained from the market. As a commercially available cyclic olefin resin, "Topas" [Ticona company (Germany)]; "Aton" [JSR Corporation]; "ZEONOR" and "ZEONEX" [Nihon Xeon Co., Ltd.]; "Apel" (manufactured by Mitsui Chemical Co., Ltd.), and the like. Such cyclic olefin resin can be formed into a film (cyclic olefin resin film) by known film forming means such as a solvent casting method or a melt extrusion method. In addition, a cyclic olefin resin film already commercially available in the form of a film can also be used. Examples of such commercially available cyclic olefin resin films include "Esshina" and "SCA40" (Sekisui Chemical Co., Ltd.); "Zeonoa Film" [Optes Corporation]; "Aton Film" [JSR Corporation], etc. are mentioned.

Moreover, also in a polycarbonate film, a film to which retardation property is imparted can be easily obtained from the market. Examples of such a polycarbonate film include a uniaxially stretched film WRF-S [(modified polycarbonate resin) manufactured by Teijin Kasei Co., Ltd.].

Subsequently, a method of imparting retardation to the polymer film will be briefly described. The polymer film can provide retardation by a known stretching method. For example, a roll (winding body) in which a polymer film is wound on a roll is prepared, the film is continuously unwound from this winding body, and the unwound film is conveyed to a heating furnace. The set temperature of the heating furnace is within the range of the polymer film's glass transition temperature (°C) to [glass transition temperature +100] (°C), preferably, the glass transition temperature (°C) to (glass transition temperature +50). It is in the range of (℃). In the heating furnace, when stretching in the advancing direction of the film or in a direction orthogonal to the advancing direction, a uniaxial or biaxial thermal stretching treatment is performed by adjusting the conveyance direction or tension to give an inclination at an arbitrary angle. The magnification of stretching is usually in the range of about 1.1 to 6 times, and preferably in the range of about 1.1 to 3.5 times. Moreover, as a method of extending|stretching in an oblique direction, as long as it can incline an orientation axis continuously at a desired angle, it does not specifically limit, A well-known drawing method can be adopted. As such a stretching method, a method described in Japanese Patent Laid-Open No. 50-83482 or Japanese Patent Laid-Open No. 2-113920 is mentioned, for example.

When used as a transparent substrate, the thickness of the polymer film is preferably thinner in that it is a weight such that practical handling is possible and sufficient transparency can be secured, but if it is too thin, the strength decreases and workability This tends to lag behind. Thus, the appropriate thickness of these films is, for example, about 5 µm to 300 µm, and preferably 20 µm to 200 µm. When this polarizing film is used as a circularly polarizing plate to be described later, it is assumed that a display device using this circularly polarizing plate is for mobile applications, and therefore the thickness of the film is particularly preferably about 20 µm to 100 µm. In addition, in the case of imparting retardation to the film by stretching, the thickness after stretching is determined by the thickness of the film before stretching and the stretching ratio.

<Orientation membrane>

It is preferable that an alignment film is formed in the base material used for manufacture of this polarizing film. In that case, the composition for forming a polarizing film is applied on the alignment film. For this reason, it is preferable that the alignment film has a solvent resistance such that it is not dissolved by application of the composition for forming a polarizing film or the like. Moreover, it is preferable to have heat resistance in heat treatment for removal of a solvent or alignment of a liquid crystal. As such an alignment film, an alignment polymer can be used.

Examples of the orientation 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, polyoxa And polymers such as sol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid or polyacrylic acid esters. Among these, polyvinyl alcohol is preferable. These oriented polymers for forming an alignment film may be used alone or in combination of two or more.

The oriented polymer is an oriented polymer composition (a solution containing an oriented polymer) dissolved in a solvent, and applied on a base material to form an alignment film on the base material. The solvent used for the orientation polymer composition is not particularly limited, but specifically, water; Alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, 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; Aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile; Ether solvents such as tetrahydrofuran and dimethoxyethane; And chlorine-substituted hydrocarbon solvents such as chloroform and chlorobenzene. These organic solvents may be used alone or in combination of multiple types.

Further, as the alignment polymer composition for forming the alignment layer, a commercially available alignment layer material may be used as it is. As a commercially available alignment film material, San Eva (registered trademark, manufactured by Nissan Chemical Industry Co., Ltd.) or optomer (registered trademark, manufactured by JSR Corporation), etc. are mentioned.

As a method of forming an alignment film on a substrate, for example, an alignment polymer composition or a commercially available alignment film material is applied to the substrate, followed by annealing to form an alignment film on the substrate. The thickness of the alignment film thus obtained is, for example, in the range of 10 nm to 10000 nm, and preferably in the range of 10 nm to 1000 nm.

In order to impart an orientation regulating force to the alignment film, it is preferable to perform rubbing as necessary (rubbing method). By providing an orientation regulating force, the polymerizable smectic liquid crystal compound can be oriented in a desired one direction (alignment direction).

As a method of imparting an orientation regulating force by the rubbing method, for example, a rubbing cloth is wound and a rotating rubbing roll is prepared, a laminate having a coating film for forming an alignment layer on a substrate is placed on a stage, and conveyed toward the rotating rubbing roll. By doing so, a method of bringing the coating film for forming an alignment film into contact with the rotating rubbing roll is mentioned.

Further, a so-called photo-alignment film can also be used. The photo-alignment film may provide an orientation regulating force by forming a photo-alignment organic layer and irradiating polarized light (preferably, polarized UV). In forming a photo-alignment organic layer, first, a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter, referred to as a "photo-alignment film-forming composition" in some cases) is prepared. The photoreactive group refers to a group that generates liquid crystal alignment ability by irradiating light (light irradiation). Specifically, a photoreaction that is the origin of the liquid crystal alignment ability, such as an orientation organic or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction of molecules generated by irradiation with light, is generated. Among the photoreactive groups, those using a dimerization reaction or a photocrosslinking reaction are preferable because they are excellent in orientation and maintain a smectic liquid crystal state at the time of forming a polarizing film. As the photoreactive group capable of causing the above reaction, it is preferable to have an unsaturated bond, particularly a double bond, and a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), A group having at least one selected from the group consisting of a nitrogen-nitrogen double 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 structures 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, and a formazane group, and those having an azoxybenzene as a basic 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 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, a photoreactive group capable of causing a light dimerization reaction is preferred, and a cinnamoyl group and a chalcone group are relatively small in amount of polarization irradiation required for photo-alignment, and a photo-alignment film having excellent thermal stability and stability over time is obtained. It is preferable because it is easy. In other words, it is particularly preferred that the polymer having a photoreactive group has a cinnamoyl group in which the terminal portion of the side chain of the polymer has a cinnamic acid structure.

A polymer or monomer having a photoreactive group is a composition for forming a photo-alignment film dissolved in a solvent, and can form a photo-alignment organic layer on the transparent substrate by coating it on a transparent substrate. The solvent used in the composition is not particularly limited, and the same solvent as used for the above-described orientation polymer composition can be applied depending on the solubility of the polymer or monomer having a photoreactive group.

The concentration of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be appropriately adjusted by the type of the polymer or monomer having this photo-reactive group or the thickness of the photo-alignment film to be manufactured, but expressed as a solid content concentration, It is preferable to set it as at least 0.2 mass %, and the range of 0.3 mass%-10 mass% is especially preferable. In addition, the composition for forming an alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer, within a range in which the characteristics of the photo-alignment film are not significantly impaired.

As a method of coating an oriented polymer or a polymer or monomer having a photoreactive group on a transparent substrate, coating methods such as spin coating, extrusion, gravure coating, die coating, bar coating and applicator methods, and flexo methods, etc. Known methods such as the printing method of are employed. In addition, when the present polarizing film is manufactured by a continuous manufacturing method of a roll-to-roll type described later, a printing method such as a gravure coating method, a die coating method, or a flexo method is usually employed as the coating method. .

<Production method of this polarizing film>

On the alignment film formed on the substrate, a composition for forming a polarizing film is applied to obtain a coating film. As a method (coating method) of applying the composition for forming a polarizing film on the alignment film, for example, the same method as exemplified as a method of coating an alignment polymer or a polymer (monomer) having a photoreactive group on a transparent substrate may be mentioned.

Next, a dry film is formed by drying and removing the solvent under conditions in which the polymerizable smectic liquid crystal compound contained in the coating film does not polymerize. As a drying method, a natural drying method, a ventilation drying method, a heat drying method, and a vacuum drying method, etc. are mentioned, for example. At this time, once the liquid crystal state of the polymerizable smectic liquid crystal compound contained in the dried film is made into a nematic phase (nematic liquid crystal state), it is preferable to transfer the nematic phase to the smectic phase. In order to form the Smectic phase via the nematic phase as described above, for example, the polymerizable Smectic liquid crystal compound contained in the dry film is heated to a temperature higher than the temperature at which the liquid crystal phase transitions to the nematic phase, and then the polymerizable Smectic liquid crystal compound is A method of cooling to a temperature indicating a mectic phase liquid crystal state is employed.

The phase transition temperature of the polymerizable Smectic liquid crystal compound to be used when the polymerizable Smectic liquid crystal compound in the dry film is made into a Smectic liquid crystal state, or the polymerizable Smectic liquid crystal compound is made into a Smectic liquid crystal state via a nematic liquid crystal state. By measuring, the conditions (heating conditions) to control the liquid crystal state can be easily obtained. The measurement conditions for this phase transition temperature measurement are described in Examples herein.

When polymerizing the polymerizable Smectic liquid crystal compound, in order to maintain the liquid crystal state of the Smectic phase satisfactorily, as a polymerizable Smectic liquid crystal compound, a composition for forming a polarizing film containing two or more polymerizable Smectic liquid crystal compounds is used. It is desirable. When a composition for forming a polarizing film in which the content ratio of two or more polymerizable Smectic liquid crystal compounds is adjusted is used, it is possible to temporarily form a supercooled state after forming the liquid crystal state of the Smectic phase via the nematic phase, There is an advantage in that it is easy to maintain the liquid crystal state of the high order smectic phase.

Next, the polymerization step of the polymerizable smectic liquid crystal compound will be described. Here, a photopolymerization initiator is contained in the composition for forming a polarizing film, and the liquid crystal state of the polymerizable smectic liquid crystal compound in the dried film is made into the smectic phase, and then the liquid crystal state of the smectic phase is maintained, while the polymerizable smectic liquid crystal compound A method of photopolymerizing is described in detail. In photopolymerization, as the light irradiated to the dry film, the kind of photopolymerization initiator contained in the dry film, or the kind of the polymerizable smectic liquid crystal compound (particularly, the kind of photopolymerizable group of the polymerizable smectic liquid crystal compound) and the amount thereof. It can be performed with light or active electron beam selected from the group consisting of visible light, ultraviolet light, and laser light as appropriate. Among these, ultraviolet light is preferred because it is easy to control the progress of the polymerization reaction, and because one widely used in the art can be used as an apparatus for photopolymerization. Therefore, it is preferable to select the kind of the polymerizable smectic liquid crystal compound or photoinitiator contained in the composition for polarizing film formation so that photopolymerization can be performed by ultraviolet light. In addition, at the time of polymerization, the polymerization temperature can also be controlled by cooling the dried film by an appropriate cooling means together with irradiation with ultraviolet light. If the polymerization of the polymerizable smectic liquid crystal compound can be carried out at a lower temperature by employing such a cooling means, there is also an advantage that the present polarizing film can be appropriately formed, even if the above-described transparent substrate has a relatively low heat resistance. .

By performing the photopolymerization as described above, the polymerizable Smectic liquid crystal compound is polymerized while maintaining the Smectic phase, preferably the liquid crystal state of the high-order Smectic phase as already illustrated, and the present polarizing film is formed. This polarizing film obtained by polymerizing the polymerizable Smectic liquid crystal compound while maintaining the Smectic liquid crystal state is dependent on the action of the azo dye (1), and maintains a conventional host guest type polarizing film, that is, a nematic liquid crystal state. There is an advantage that the polarization performance is much higher than that of a polarizing film obtained by polymerizing a polymerizable liquid crystal compound or the like while maintaining.

The thickness of this polarizing film is preferably in the range of 0.5 µm or more and 10 µm or less, and more preferably 1 µm or more and 5 µm or less. Therefore, the thickness of the coating film for forming the polarizing film is determined in consideration of the thickness of the obtained polarizing film. In addition, the thickness of this polarizing film is calculated|required by measurement of an interference film thickness meter, a laser microscope, or a stylus type film thickness meter.

This polarizing film formed in this way contains two or more kinds of dichroic dyes having different maximum absorption wavelengths, preferably two or more kinds of azo dyes 1, particularly preferably of the azo dyes 1 shown in Table 1. By using the composition for forming a polarizing film containing a combination, it becomes what has an absorption spectrum satisfying the relationship of Formulas (I) to (V). In particular, when a composition containing a combination of the azo dyes (1) shown in Table 1 is used as the composition for forming a polarizing film, the present invention having an absorption spectrum that satisfies the relationship of formulas (I) to (V) more easily A polarizing film can be obtained.

Moreover, this polarizing film formed in this way is especially preferable as long as a black peak is obtained by X-ray reflection measurement. As the present polarizing film from which such a black peak is obtained, for example, the present polarizing film exhibiting a diffraction peak derived from a hexatic phase or a crystal phase can be mentioned.

In addition, it is preferable that this polarizing film has a luminous sensitivity correcting single transmittance (Ty) of 43% or more, and a luminous intensity correcting single polarization degree (Py) of 90% or more. The luminous sensitivity correcting single transmittance (Ty) and the luminous intensity correcting single polarization (Py) refer to the transmittance (T ¹ ) in the transmission axis direction of the present polarizing film and the transmittance in the absorption axis direction (T) in the wavelength range of 300 nm to 800 nm. ² ) is measured, the single transmittance and the polarization degree are calculated using the following formulas (VI) and (VII), and the luminous sensitivity is corrected according to the second degree field of view (C light source) of JIS Z8701.

Ty(%)=(T ¹ +T ² )/2 Equation (VI)

Py(%)={(T ¹ -T ² )/(T ¹ +T ² )}×100 Equation (VII)

<Continuous manufacturing method of this polarizing film (this circular polarizing plate)>

* As mentioned above, the outline of the manufacturing method of this polarizing film was demonstrated, but when manufacturing this polarizing film commercially, the method which can manufacture this polarizing film continuously is required. This continuous manufacturing method is based on a roll-to-roll format, and in some cases, it is referred to as "this manufacturing method". In addition, in this manufacturing method, as a base material, the case of using a transparent base material imparted with retardation is mainly demonstrated.

This manufacturing method is, for example,

A step of preparing a first roll in which a transparent substrate is wound around the first winding core,

The process of continuously sending the transparent substrate from the first roll, and

A step of continuously forming a first coating film on a transparent substrate by applying a composition containing a polymer and a solvent having a photoreactive group;

A step of drying and removing the solvent from the first coating film to form a first dry film on the transparent substrate to continuously obtain a first laminate; and

The step of forming a photo-alignment film by irradiating the first dry film with polarized UV light to continuously obtain a second laminate;

A step of applying a composition containing a polymerizable smectic liquid crystal compound, a dichroic dye and a solvent on the photo-alignment film, and continuously forming a second coating film on the photo-alignment film,

A step of continuously obtaining a third laminate by forming a second dry film on the photo-alignment film by drying the second coating film under conditions in which the polymerizable smectic liquid crystal compound contained in the second coating film is not polymerized; and ,

After making the polymerizable smectic liquid crystal compound contained in the second dry film into a smectic liquid crystal state, and polymerizing the polymerizable smectic liquid crystal compound while maintaining the smectic liquid crystal state, a step of continuously obtaining a polarizing film and ,

It has a process of winding up the polarizing film obtained continuously on a 2nd winding core, and obtaining a 2nd roll. Here, with reference to FIG. 1, the main part of this manufacturing method is demonstrated.

The first roll 210 in which the transparent substrate is wound around the first winding core 210A can be easily obtained from the market, for example. Examples of the transparent substrate available on the market in the form of such a roll include films made of cellulose ester, cyclic olefin resin, polyethylene terephthalate, polycarbonate or polymethacrylic acid ester, among the transparent substrates already exemplified. . In addition, when the present polarizing film is obtained in the form of a circularly polarizing plate, a transparent substrate with retardation property is also readily available on the market, and for example, a retardation film made of a cellulose ester, polycarbonate or cyclic olefin resin And the like.

Subsequently, the transparent substrate is released from the first roll 210. The method of unwinding the transparent substrate is performed by providing a suitable rotating means to the winding core 210A of the first roll 210 and rotating the first roll 210 by the rotating means. Further, an appropriate auxiliary roll 300 may be provided in the direction in which the transparent substrate is conveyed from the first roll 210, and the transparent substrate may be unscrewed by the rotating means of the auxiliary roll 300. Further, by providing rotation means for both the first winding core 210A and the auxiliary roll 300, the transparent substrate may be unwound while providing an appropriate tension to the transparent substrate.

When the transparent substrate unwound from the first roll 210 passes through the coating apparatus 211A, the composition for forming an alignment film is applied on the surface thereof by the coating apparatus 211A. As described above in order to continuously apply the composition for forming an alignment film in this way, the coating apparatus 211A is a printing method such as a gravure coating method, a die coating method, and a flexo method.

The film passed through the coating device 211A corresponds to a laminate of a transparent substrate and a first coating film. The transparent substrate on which the first coating film is formed (laminated) in this way is conveyed to the drying furnace 212A, heated by the drying furnace 212A, and converted into a first laminate comprising the transparent substrate and the first dry film (轉化). As the drying furnace 212A, for example, a hot air drying furnace or the like is used. The set temperature of the drying furnace 212A is determined according to the kind of solvent contained in the composition for forming an alignment film applied by the coating device 211A. In addition, the drying furnace 212A may be divided into appropriate zones, and the set temperature may be different for each of the plurality of zones. A plurality of drying furnaces are arranged in series, and the drying furnaces are operated at different set temperatures. It may be of a format in which the film sequentially conveys the drying furnaces.

The first laminated body continuously formed by passing through the heating furnace 212A is then polarized to the surface of the first dry film side or the surface of the transparent substrate side of the laminate by a polarization UV irradiation device 213A. UV is irradiated, and the first dry film turns into a light polarizing film. In this case, the angle between the transport direction D1 of the film and the orientation direction D2 of the formed photo-alignment film is approximately 45°. 2 is a diagram schematically showing a relationship between the orientation direction (D2) of the photo-alignment film formed after polarized UV irradiation and the transport direction (D1) of the film. In other words, FIG. 1 shows the surface of the first laminate after passing through the polarized UV irradiation device 213A, when viewed in the transport direction D1 of the film and the orientation direction D2 of the photo-alignment film, the angle formed by them is approximately 45°. It shows that it represents.

The first laminated body formed continuously in this way passes through the drying furnace 212B after the composition for forming a polarizing film is applied on the photo-alignment film of the first laminated body by passing through the coating device 211B. By doing so, the polymerizable smectic liquid crystal compound contained in the second layered product or the second dry film of the second layered product becomes a layered product in which a smectic liquid crystal state is formed. The drying furnace 212B serves to dry and remove the solvent from the composition for forming a polarizing film applied on the photo-alignment film, and heat energy so that the polymerizable smectic liquid crystal compound contained in the second dry film becomes a smectic liquid crystal state. Plays a role of imparting to the second dry film. In addition, as already described, in order to make the polymerizable Smectic liquid crystal compound into a Smectic liquid crystal state, and once the polymerizable Smectic liquid crystal compound is into a nematic liquid crystal state, the first layered product is subjected to different heating conditions. , Multi-stage heat treatment should be performed on the first laminate. For this reason, the drying furnace 212B is composed of a plurality of zones having different set temperatures, as described in the drying furnace 212A, or a plurality of drying furnaces having different set temperatures are prepared, and a plurality of drying furnaces are installed in series. It is preferable if it is a form of saying that.

In the film passing through the drying furnace 212B, the solvent contained in the composition for forming a polarizing film is sufficiently removed, and the polymerizable smectic liquid crystal compound in the second dry film is irradiated with light while maintaining the smectic liquid crystal state. It is conveyed to the apparatus 213B. By light irradiation by the light irradiation device 213B, the polymerizable smectic liquid crystal compound is photopolymerized while maintaining the liquid crystal state, and the present polarizing film is continuously formed on the alignment film.

This polarizing film formed continuously in this way is wound around the second winding core 220A in the form of a laminate including a transparent substrate and an alignment film, so that the shape of the second roll 220 is obtained. When the formed polarizing film is wound up to obtain a second roll, it may be wound together using an appropriate spacer.

Thus, the transparent substrate is the first roll / coating device 211A / drying furnace 212A / polarized UV irradiation device 213A / coating device 211B / drying furnace 212A / light irradiation device 213A By passing through in order, the polarizing film seen on the photo-alignment film on the transparent substrate is continuously produced.

In addition, in the present manufacturing method shown in Fig. 1, a method of continuously manufacturing the polarizing film seen from the transparent substrate is shown. For example, the transparent substrate is the first roll/coating device 211A/drying furnace 212A/ By sequentially passing through the polarized UV irradiation device 213A, the continuously formed first laminate is wound around the winding core, the first laminate is manufactured in the form of a roll, and the first laminate is unwound from the roll and unwound. The first laminated body thus obtained may be passed through in the order of the coating device 211B/drying furnace 212A/light irradiation device 213A to produce the present polarizing film.

Above, the configuration and manufacturing method of the present polarizing film have been described centering on the case in the form of a laminate of a transparent substrate/photo-alignment film/this polarizing film, but as described above, the present polarizing film is a photo-alignment film or a transparent substrate from such a laminate. May be peeled off, or a layer or film other than the transparent substrate/photo-alignment film/this polarizing film may be laminated on the laminate. As these layers and films, as already mentioned, this polarizing film may further include a retardation film, and may further include an antireflection layer or a brightness improving film.

Further, by using the transparent substrate itself as a retardation film, a circular polarizing plate or an elliptically polarizing plate in the form of a retardation film/photo-alignment film/this polarizing film can also be used. For example, in the case of using a uniaxially stretched 1/4 wavelength plate as a retardation film, by setting the irradiation direction of polarized UV to be approximately 45° with respect to the transport direction of the transparent substrate, manufacturing a circularly polarizing plate by roll-to-roll It is possible. It is preferable that the quarter-wave plate used when manufacturing the circularly polarizing plate as described above has a characteristic in which the in-plane retardation value for visible light decreases as the wavelength decreases.

In addition, a 1/2 wave plate was used as the retardation film, and a linear polarizing plate roll set was prepared by shifting the angle of the slow axis and the absorption axis of the polarizing film, and a 1/4 wave plate was further placed on the side opposite to the side where the polarizing film was formed. By forming, it is also possible to obtain a broadband circularly polarizing plate.

In the present manufacturing method described above, the transparent substrate may be replaced with a substrate having no retardation property. In this case, in order to manufacture this circularly polarizing plate, first, from the laminate of the base material (no phase difference)/photo-alignment film/this polarizing film obtained after the implementation of the present manufacturing method, the present polarizing film was peeled to form a winding body 225. do. Meanwhile, a winding body 230 on which a retardation film is wound is prepared. Then, the polarizing film seen from the winding body 225 and the retardation film are continuously unwrapped from the winding body 230 and bonded together by a suitable method, whereby the circular polarizing plate can be manufactured. The main part of this method is shown in FIG. Also in this case, with respect to the orientation direction of the retardation film and this polarizing film, it is good to bond so that it may become approximately 45 degrees. In addition, when bonding this polarizing film and a retardation film, you may bond this polarizing film and a retardation film through an adhesive layer formed from an adhesive using a suitable adhesive.

In addition, in the case of obtaining that the present polarizing film produced by the present manufacturing method has an absorption spectrum that satisfies the relationship of formulas (I) to (V), the present polarizing film is obtained in a single film state by peeling off the transparent substrate, etc. , It is sufficient to measure the absorption spectrum of this single-layered polarizing film by the normal method, for example, by measuring the absorption spectrum of a transparent substrate in advance, and using the absorption spectrum of this transparent substrate as a baseline, it is formed on a transparent substrate, etc. The method of measuring the absorption spectrum of the main polarizing film as a body, or by measuring the absorption spectrum of the transparent substrate in advance, and then measuring the absorption spectrum of the main polarizing film formed on the transparent substrate, etc. A method of determining the difference between the absorption spectrum of the present polarizing film as formed above and the absorption spectrum of the transparent substrate may be used. By using these means for measuring the absorption spectrum of the transparent substrate or the like in advance, the absorption spectrum of the viewed polarizing film can be easily obtained without peeling the transparent substrate or the like.

<Use of this polarizing film>

This polarizing film makes it possible to manufacture this circularly polarizing plate which is very useful for an organic EL (electroluminescent) display device. Further, this display device may be an inorganic electroluminescent (EL) display device.

4 and 6 are schematic diagrams schematically showing a cross-sectional configuration of an EL display device using the present polarizing film (hereinafter, referred to as “the present organic EL display device” in some cases).

This organic EL display device 30 using this polarizing film will be described with reference to FIG. 4. When the present polarizing film is used for the present organic EL display device, it is preferable to use the present polarizing film after making it a circular polarizing plate (hereinafter, referred to as "the present circular polarizing plate" in some cases). There are two embodiments of this circularly polarizing plate. Therefore, before describing the configuration of the organic EL display device 30 and the like, two embodiments of the circularly polarizing plate will be described with reference to FIG. 5.

5(C1) is a cross-sectional view schematically showing a first embodiment of the circularly polarizing plate 110. This first embodiment is the original circularly polarizing plate 110 in which a phase difference layer (phase difference film) 4 is further provided on the polarizing film 3. FIG. 5C2 is a cross-sectional view schematically showing a second embodiment of the circularly polarizing plate 110. In this second embodiment, as the transparent substrate 1 used when manufacturing a polarizer, by using a transparent substrate (phase difference film) to which retardation has been previously imparted, the transparent substrate 1 itself is used as the retardation layer 4. This is the circular polarizing plate 110 that has both functions.

In this organic EL display device 30, an organic functional layer 36 as a light emitting source and a cathode electrode 37 are stacked on a substrate 33 on which a pixel electrode 35 is formed. A circularly polarizing plate 31 is disposed on the side opposite to the organic functional layer 36 with the substrate 33 interposed therebetween, and the circularly polarizing plate 110 is used as the circularly polarizing plate 31. The organic functional layer 36 emits light by applying a positive voltage to the pixel electrode 35 and a negative voltage to the cathode electrode 37 and applying a direct current between the pixel electrode 35 and the cathode electrode 37 . The organic functional layer 36 as a light emitting source includes an electron transport layer, a light emitting layer, a hole transport layer, and the like. The light emitted from the organic functional layer 36 passes through the pixel electrode 35, the interlayer insulating film 34, the substrate 33, and the circularly polarizing plate 31 (this circularly polarizing plate 110). The organic EL display device having the organic functional layer 36 will be described, but it may also be applied to the inorganic EL display device having the inorganic functional layer.

In order to manufacture the organic EL display device 30, first, a thin film transistor 40 is formed on a substrate 33 in a desired shape. Then, the interlayer insulating film 34 is formed, and then the pixel electrode 35 is formed by a sputtering method and patterned. After that, the organic functional layer 36 is laminated.

Next, a circularly polarizing plate 31 (this circularly polarizing plate 110) is provided on a surface of the substrate 33 opposite to the surface on which the thin film transistor 40 is installed.

When this circularly polarizing plate 110 is used as the circularly polarizing plate 31, the lamination procedure will be described with reference to an enlarged view of portion C surrounded by a dotted line in FIG. When this circularly polarizing plate 110 is used as the circularly polarizing plate 31, the retardation layer 4 in the circularly polarizing plate 110 is disposed on the substrate 33 side. FIG. 5(C1) is an enlarged view using the first embodiment of the circularly polarizing plate 110 as the circularly polarizing plate 31, and FIG. 5(C2) is a second embodiment of the circularly polarizing plate 110 Is an enlarged view using as the circularly polarizing plate 31.

Next, members other than the main polarizing film 31 (circular polarizing plate 110) of the organic EL display device 30 will be briefly described.

As the substrate 33, a ceramic substrate such as a sapphire glass substrate, a quartz glass substrate, a soda glass substrate, and alumina; Metal substrates such as copper; And plastic substrates. Although not shown, a thermally conductive film may be formed on the substrate 33. Examples of the thermally conductive film include a diamond thin film (DLC, etc.). When the pixel electrode 35 is of a reflective type, light is emitted in a direction opposite to that of the substrate 33. Therefore, not only a transparent material but also a non-transparent material such as stainless steel can be used. The substrate may be formed singly, or may be formed as a laminated substrate by bonding a plurality of substrates with an adhesive. In addition, these substrates are not limited to a plate-like one, and may be a film.

As the thin film transistor 40, for example, a polysilicon transistor or the like may be used. The thin film transistor 40 is provided at the end of the pixel electrode 35 and has a size of about 10 nm to 30 μm. Further, the size of the pixel electrode 35 is about 20 μm×20 μm to 300 μm×300 μm.

On the substrate 33, a wiring electrode of the thin film transistor 40 is provided. The wiring electrode has a low resistance and has a function of reducing the resistance value by being electrically connected to the pixel electrode 35. In general, the wiring electrode is Al, Al and a transition metal (except for Ti), Ti or Those containing any one or two or more of titanium nitride (TiN) are used.

An interlayer insulating film 34 is provided between the thin film transistor 40 and the pixel electrode 35. The interlayer insulating film 34 is formed of an inorganic material such as silicon oxide such as SiO ₂ or silicon nitride by sputtering or vacuum evaporation, a silicon oxide layer formed of SOG (spin-on glass), photoresist, polyimide, and acrylic resin. Any material may be used as long as it has insulating properties, such as a coating film of a resin-based material such as.

On the interlayer insulating film 34, a rib 41 is formed. The ribs 41 are disposed in the periphery (between adjacent pixels) of the pixel electrode 35. Examples of the material for the ribs 41 include acrylic resins and polyimide resins. The thickness of the rib 41 is preferably 1.0 µm or more and 3.5 µm, and more preferably 1.5 µm or more and 2.5 µm or less.

Next, an EL element including the pixel electrode 35 as a transparent electrode, the organic functional layer 36 as a light emitting source, and the cathode electrode 37 will be described. The organic functional layer 36 has at least one hole transport layer and a light emitting layer, respectively, and has, for example, an electron injection transport layer, a light emitting layer, a hole transport layer, and a hole injection layer in sequence.

Examples of the pixel electrode 35 include ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), IGZO, ZnO, SnO ₂ and In ₂ O ₃ , but particularly ITO and IZO are preferable. The thickness of the pixel electrode 35 should have a thickness of a certain or more sufficient to sufficiently perform hole injection, and is preferably about 10 nm to 500 nm.

The pixel electrode 35 can be formed by a vapor deposition method (preferably a sputtering method). The sputtering gas is not particularly limited, and inert gases such as Ar, He, Ne, Kr, and Xe, or a mixture of these gases may be used.

Metal elements such as K, Li, Na, Mg, La, Ce, Ca, Sr, Ba, Al, Ag, In, Sn, Zn and Zr may be used as the material for the cathode electrode 37, but In order to improve the operational stability, it is preferable to use a two- or three-component alloy system selected from exemplified metal elements. Examples of alloy systems include Ag·Mg (Ag: 1 at% to 20 at%), Al·Li (Li: 0.3 at% to 14 at%), In·Mg (Mg: 50 at% to 80 at%), and Al·Ca (Ca: 5 at% to 20 at%) and the like are preferable.

The cathode electrode 37 is formed by a vapor deposition method, a sputtering method, or the like. The thickness of the cathode electrode 37 is preferably 0.1 nm or more, preferably 1 nm to 500 nm or more.

The hole injection layer has a function of facilitating injection of holes from the pixel electrode 35, and the hole transport layer has a function of transporting holes and a function of blocking electrons, and is also referred to as a charge injection layer or a charge transport layer. .

The thickness of the light emitting layer, the combined thickness of the hole injection layer and the hole transport layer, and the thickness of the electron injection transport layer are not particularly limited, and vary depending on the formation method, but are preferably about 5 nm to 100 nm. Various organic compounds can be used for the hole injection layer or the hole transport layer. In the formation of the hole injection transport layer, the light emitting layer, and the electron injection transport layer, a vacuum vapor deposition method can be used because a homogeneous thin film can be formed.

As the organic functional layer 36 as a light emitting source, use of light emission (fluorescence) from singlet excitons, light emission from triplet excitons (phosphorescence), light emission from singlet excitons (fluorescence) and triplet Including those using light emission (phosphorescence) from excitons, those formed by organic substances, those formed by organic substances and those formed by inorganic substances, those containing polymer materials, low molecular materials, high molecular materials and low molecular materials, etc. You can use However, the present invention is not limited to this, and the organic functional layer 36 using various known materials for the EL element can be used for the organic EL display device 30.

A desiccant 38 is disposed in the space between the cathode electrode 37 and the sealing cover 39. This is because the organic functional layer 36 is weak against humidity. Moisture is absorbed by the desiccant 38 to prevent deterioration of the organic functional layer 36.

6 is a schematic diagram showing a cross-sectional configuration of another embodiment of the organic EL display device 30. This organic EL display device 30 has a sealing structure using the thin film sealing film 41, and the emitted light can also be obtained from the opposite surface of the array substrate.

As the thin film sealing film 41, it is preferable to use a DLC film in which DLC (diamond carbon) is deposited on a film of an electrolytic capacitor. The DLC film has a property of very poor moisture permeability, and has high moisture-proof performance. Further, a DLC film or the like may be formed by depositing directly on the surface of the cathode electrode 37. Further, a thin film sealing film 41 may be formed by laminating a resin thin film and a metal thin film in multiple layers.

As described above, there is provided a novel organic EL display device comprising a novel polarizing film (this polarizing film) according to the present invention, and a circular polarizing plate including the present polarizing film.

When the present organic EL display device includes the present circularly polarizing plate including the present polarizing film, the intensity of light at a wavelength of 450 nm is I450, the intensity of light at a wavelength of 550 nm is I550, and the intensity of light at a wavelength of 650 nm is I650. ,

1≤I450/I550<2 (X)

1≤I450/I650<2 (XI)

It has an emission spectrum that satisfies all of the relationships represented by. In this organic EL display device, since this polarizing film hardly absorbs light from an organic EL light-emitting element, particularly blue light with a short life (light-emitting element with a wavelength of 450 nm), the light emission intensity of the organic EL light-emitting element is increased. There is no need, and it is possible to achieve a longer life of the organic EL image display device. For this reason, this polarizing film and this circularly polarizing plate are of very high industrial value.

[Example]

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

In this example, the following polymerizable smectic liquid crystal compound was used.

Compound (2-6) (compound represented by the following formula (2-6))

Compound (2-6) is described in Lub et al. Recl. Trav. Chim. It was synthesized by the method described in Pays-Bas, 115, 321-328 (1996).

[Measurement of phase transition temperature]

The phase transition temperature of compound (2-6) was confirmed by determining the phase transition temperature of the film made of compound (2-6). The operation is as follows.

A film made of compound (2-6) was formed on the glass substrate on which the alignment film was formed, and while heating, the phase transition temperature was confirmed by texture observation with a polarizing microscope (BX-51, manufactured by Olympus). The film made of compound (2-6) is heated up to 120°C, and when the temperature is lowered, the phase transitions to the nematic phase at 112°C, the phase transitions to the Smectic A phase at 110°C, and the phase transitions to the Smectic B phase at 94°C. I confirmed that.

Compound (2-8) (compound represented by the following formula (2-8))

Compound (2-8) was synthesized by referring to the synthesis of compound (2-6) described above.

[Measurement of phase transition temperature]

The phase transition temperature of compound (2-8) was confirmed in the same manner as the measurement of the phase transition temperature of compound (2-6). Compound (2-8), when the temperature was raised to 140°C and then lowered, the phase transition from 131°C to the nematic phase, 80°C to the Smectic phase A, and 68°C to the Smectic B phase. I did.

Example 1

[Preparation of a composition for forming a polarizing film]

The components shown in Table 3 were mixed and stirred at 80°C for 1 hour to obtain a composition for forming a polarizing film. In addition, the structure and compounding composition of each component (refer to Table 3 for the composition of a dichroic dye) are as follows.

Polymerizable smectic liquid crystal compounds; 90 parts of compound (2-6)

Compound (2-8) 10 parts

Dichroic pigment;

2.5 parts of compound (1-5)

2.5 parts of compound (1-8)

2.5 parts of compound (1-21)

Polymerization initiator;

2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure369; manufactured by Chiba Specialty Chemicals) 6 parts

Leveling agents;

1.2 parts of polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

solvent; 250 parts xylene

[Measurement of phase transition temperature]

As in the case of compound (2-6) and compound (2-8), a mixture of compound (2-6) and compound (2-8) contained in the composition for forming a polarizing film prepared as described above (compound ( As for the mixing ratio of 2-6) and compound (2-8), the phase transition temperature of 90 parts: 10 parts) was determined. It was confirmed that the polymerizable liquid crystal compound was heated to 140°C and then, when the temperature was lowered, the phase transition from 116°C to the nematic phase, 107°C to the Smectic A phase, and to the Smectic B phase at 76°C. .

[Production and evaluation of this polarizing film]

1. Formation of alignment layer

A glass substrate was used as the transparent substrate.

On a glass substrate, a 2 mass% aqueous solution (orientation polymer composition) of polyvinyl alcohol (polyvinyl alcohol 1000 complete saponification type, manufactured by Wako Pure Chemical Industries, Ltd.) was applied by spin coating, and after drying, a thickness of 100 nm. A film was formed. Subsequently, an alignment film was formed by performing a rubbing treatment on the surface of the obtained film. The rubbing treatment was carried out using a semi-automatic rubbing device (brand name: LQ-008 type, manufactured by Joyoko Gaku Co., Ltd.) and using a cloth (brand name: YA-20-RW, manufactured by Yoshikawa Kako Co., Ltd.), a press fit of 0.15 mm, rotation speed It was carried out under conditions of 500 rpm and 16.7 mm/s. By such a rubbing treatment, a laminate 1 in which an alignment film was formed on a glass substrate was obtained.

2. Formation of polarizing film

On the alignment film of the laminate 1, a composition for forming a polarizing film was applied by a spin coating method, heated and dried for 1 minute on a hot plate at 120°C, and then quickly cooled to room temperature to form a dry film on the alignment film. I did. In such a dry film, the liquid crystal state of the polymerizable Smectic liquid crystal compound contained was Smectic B phase. Next, in a nitrogen atmosphere, using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.), ultraviolet rays are irradiated to the dry film at an exposure dose of 2000 mJ/cm 2 (365 nm basis) to be included in the dry film. The resulting polymerizable liquid crystal compound was polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal compound to form a polarizing film from a dried film. The thickness of the polarizing film at this time was measured with a laser microscope (OLS 3000 manufactured by Olympus) and found to be 1.8 µm.

4. Measurement of absorbance and transmittance

In order to confirm the usefulness of this polarizer, absorbance was measured as follows. The absorbance in the direction of the transmission axis (A ¹ ) and the absorbance in the direction of the absorption axis (A ² ) were measured from a wavelength of 300 nm to 300 nm by a double beam method using a device in which a folder with a polarizer was set in a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation). Spectra were measured in the range of 800 nm. In the folder, a mesh was installed to cut the amount of light by 50% on the reference side. The values of the absorbance A450, A550, A650, absorbance ratios A450/A550 and A450/A650 in the absorption axis direction at wavelengths of 450 nm, 550 nm and 650 nm were determined. In this spectrum measurement, the absorption spectrum of the layered product 1 for forming the present polarizing film was measured in advance, and the absorption spectrum was corrected by taking the absorption spectrum as a baseline.

Further, the luminous sensitivity corrected polarization degree (Py) and the luminous sensitivity corrected transmittance (Ty) calculated from the spectrum result were obtained. Table 2 shows the results of these measurements. In addition, the luminous sensitivity corrected polarization degree (Py) and the luminous sensitivity corrected transmittance (Ty) are measured by measuring the transmittance (T ¹ ) in the transmission axis direction and the transmittance in the absorption axis direction (T ² ) in a wavelength range of 300 nm to 800 nm, It is the value obtained by calculating the single transmittance and the degree of polarization using the following formulas (VI) and (VII), and correcting the luminous intensity using a 2-degree field of view (C light source) of JIS Z8701.

Ty(%)=(T ¹ +T ² )/2 Equation (VI)

Py(%)={(T ¹ -T ² )/(T ¹ +T ² )}×100 Equation (VII)

In Examples 2 to 8, a polarizing film was produced in the same manner as in Example 1 except that the type of the dichroic dye was changed. Table 1 shows the results of the amount of dichroic dye added and the film thickness of the produced polarizing film. In addition, the absorption spectrum was similarly measured. The values of absorbance A450, A550, A650, absorbance ratios A450/A550, and A450/A650 in the absorption axis direction at wavelengths of 450 nm, 550 nm and 650 nm were measured. In addition, similarly, the measurement results of the luminance corrected polarization degree (Py) and the luminous sensitivity corrected transmittance (Ty) are shown in Table 4.

Reference Example 1

[Production of iodine PVA polarizing plate]

A polyvinyl alcohol film having a thickness of 75 μm at an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more was uniaxially stretched to about 5.5 times in a dry manner, and immersed in pure water at 60° C. for 60 seconds while maintaining a tension state, It was immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.05/5/100 at 28°C for 20 seconds. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100 at 72°C for 300 seconds. Subsequently, after washing with pure water at 26° C. for 20 seconds, it was dried at 65° C. to obtain a polarizing film in which iodine was adsorbed and oriented to a polyvinyl alcohol resin.

On both surfaces of the polarizer thus obtained, 3 parts of carboxyl group-modified polyvinyl alcohol [Kurarepoval KL318 manufactured by Kuraray Corporation] and a water-soluble polyamide epoxy resin [Sumirez Resin 650 manufactured by Sumika Chemtex Corporation (aqueous solution having a solid content concentration of 30%) )] A polarizing film was prepared by protecting both sides with a saponified triacetylcellulose film [KC8UX2MW manufactured by Konica Minoltaopt Corporation] through a polyvinyl alcohol-based adhesive prepared from 1.5 parts.

Reference Example 2

A polarizing film was produced in the same manner as in Comparative Example 1 except that the weight ratio of iodine/potassium iodide/water was immersed in an aqueous solution having a weight ratio of 0.05/5/100 at 28°C for 35 seconds.

About the polarizing film thus produced, spectrum measurement was performed in the same manner as in Example 1. Measurement of absorbance values A450, A550, A650, absorbance ratios A450/A550, A450/A650 in the direction of absorption axis at wavelengths 450 ㎚, 550 ㎚, 650 ㎚ and luminous intensity corrected polarization degree (Py), luminous sensitivity corrected transmittance (Ty) The results are shown in Table 4.

[Table 3]

[Table 4]

Example 9

[Production of photo-alignment film on phase difference film]

Photo-alignment polymer of the following formula (3) using a retardation film (uniaxially stretched film WRF-S (modified polycarbonate resin), a retardation value of 137.5 nm, a thickness of 50 μm, manufactured by Teijin Kasei Co., Ltd.) as a transparent substrate Was applied by a bar coat method and dried at 120° C. to obtain a dry film. On this dried film, polarized UV was irradiated in the direction of 45° with respect to the slow axis of the retardation film to obtain a photo-alignment film. Polarized UV treatment was performed under conditions of 100 mJ of intensity measured at a wavelength of 365 nm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Electric Corporation).

〔Manufacture of circularly polarizing plate〕

On the photo-alignment film, the composition for forming a polarizing film prepared in Example 1 was applied by a bar coating method, heated and dried in a drying oven at 120° C. for 1 minute, and then cooled to room temperature. In such a dry film, the liquid crystal state of the polymerizable liquid crystal compound contained was the Smectic B phase. Subsequently, using a UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Denki Co., Ltd.), by irradiating the layer formed from the composition for forming a polarizing film with ultraviolet rays having an exposure amount of 2000 mJ/cm 2 (365 nm), The polymerizable liquid crystal compound contained in the dry film was polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film was formed from the dry film.

The film thickness of the polarizing film at this time was measured with a laser microscope (OLS 3000 manufactured by Olympus) and found to be 1.8 µm.

Example 10

In place of the composition for forming a polarizing film prepared in Example 1, the same experiment as in Example 9 was performed except that the composition for forming a polarizing film prepared in Example 2 was used to prepare a circularly polarizing plate.

Example 11

In place of the composition for forming a polarizing film prepared in Example 1, the same experiment as in Example 9 was conducted except for using the composition for forming a polarizing film prepared in Example 8 to prepare a circularly polarizing plate.

Reference Example 3

The absorption axis of the polarizing film prepared in Reference Example 1 and the slow axis of the retardation film (uniaxially stretched film WRF-S (modified polycarbonate resin), retardation value 137.5 nm, thickness 50 μm, manufactured by Teijin Kasei Co., Ltd.) A circularly polarizing plate was manufactured by bonding through an adhesive so that the angle formed was 45°.

Reference Example 4

In place of the polarizing film prepared in Reference Example 1, the same experiment as in Reference Example 3 was conducted except for using the polarizing film prepared in Reference Example 2 to prepare a circularly polarizing plate.

<Measurement of optical properties>

The retardation film of the circularly polarizing plate obtained in Examples 9 to 10 and Reference Examples 3 to 4, respectively, and an aluminum metal plate were bonded to each other through a pressure-sensitive adhesive, and the reflectance at wavelengths of 450 nm, 550 nm, and 650 nm was carried out in the same manner as the transmittance measurement. Was measured. In addition, luminous sensitivity was corrected using a 2-degree field of view (C light source) of JIS Z8701 to calculate luminous sensitivity corrected reflectance. The results are shown in Table 4.

It can be seen that the circularly polarizing plate produced from this polarizing film has good antireflection properties with respect to human luminous sensitivity.

[Table 5]

This polarizing film is very useful in manufacturing a liquid crystal display device, an (organic) EL display device, and a projection type liquid crystal display device.

1: transparent substrate, 2: photo-alignment film. 3: this polarizing film, 100: polarizer, 101: first laminate, 102: second laminate, 103: third laminate, 210: first roll, 210A: winding core, 220: second roll, 220A: Winding core, 211A, 211B: coating device, 212A, 212B: drying furnace, 213A: polarized UV irradiation device, 213B: light irradiation device, 300: auxiliary roll, 30: EL display device, 31: polarizing film, 32: retardation film , 33: substrate, 34: interlayer insulating film, 35: pixel electrode, 36: light emitting layer, 37: cathode electrode, 38: desiccant, 39: sealing cover, 40: thin film transistor, 41: rib, 42: thin film sealing film, 44: EL display device

Claims (8)

A dichroic dye containing the structure of the following formula (1) and

Dichromatic dye containing the structure of the following formula (2)

As a polarizing film formed from a composition containing at least,
A polarizing film having an orientation direction in one direction and having an absorption spectrum that satisfies all the relationships represented by the following formulas (I) to (V):
0.3≤A450/A550<0.8 (I)
0.3≤A450/A650<1.0 (II)
0.5≤A450≤2 (III)
1≤A550≤3 (IV)
1≤A650≤3 (V)
(In the formula,
A450 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 450 nm,
A550 is the absorbance of polarized light parallel to the orientation direction at a wavelength of 550 nm,
A650 represents the absorbance of polarized light parallel to the orientation direction at a wavelength of 650 nm.) The polarizing film according to claim 1, wherein the composition is a composition further containing a polymerizable smectic liquid crystal compound. The polarizing film according to claim 1 or 2, wherein the luminous sensitivity correction unit transmittance (Ty) is 43% or more and the luminous sensitivity correction unit polarization degree (Py) is 90% or more. A circularly polarizing plate having the polarizing film according to claim 1 or 2 and a λ/4 layer and satisfying the following requirements (A1) and (A2):
(A1) the angle formed by the absorption axis of the polarizing film and the slow axis of the λ/4 layer is 45°;
(A2) The value of the frontal retardation of the λ/4 layer measured with light having a wavelength of 550 nm is in the range of 100 nm to 150 nm. The circularly polarizing plate according to claim 4, wherein the value of the front retardation of the λ/4 layer for visible light decreases as the wavelength decreases. A circularly polarizing plate having the polarizing film according to claim 4, a λ/2 layer, and a λ/4 layer in this order, and satisfying the following requirements (B1) to (B4):
(B1) the angle formed by the absorption axis of the polarizing film and the slow axis of the λ/2 layer is 15°;
(B2) the angle formed by the slow axis of the λ/2 layer and the slow axis of the λ/4 layer is 60°;
(B3) the λ/2 layer has a front retardation value of the λ/4 layer measured with light having a wavelength of 550 nm in the range of 200 nm to 300 nm;
(B4) The λ/4 layer has a front retardation value of the λ/4 layer measured with light having a wavelength of 550 nm in the range of 100 nm to 150 nm. An organic EL display device comprising the circularly polarizing plate according to claim 4 and an organic EL element. The method according to claim 7, wherein, among the light emitted from the light emitting layer, when the intensity of light having a wavelength of 450 nm is set to I450, the intensity of light having a wavelength of 550 nm is set to I550, and the intensity of light having a wavelength of 650 nm is set to I650,
1≤I450/I550<2 (X)
1≤I450/I650<2 (XI)
An organic EL display device having an emission spectrum satisfying all of the relationships represented by.

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