JP4784417B2 - Composition for anisotropic dye film, anisotropic dye film and polarizing element - Google Patents

Description

  The present invention forms an anisotropic dye film having high dichroism useful for a polarizing film or the like included in a display element of a light control element, a liquid crystal element (LCD), or an organic electroluminescence element (OLED). The present invention relates to an anisotropic dye film composition that can be used, an anisotropic dye film formed using the anisotropic dye film composition, and a polarizing element using the anisotropic dye film.

  In the LCD, a linearly polarizing plate or a circularly polarizing plate is used to control optical rotation and birefringence in display. Also in OLED, a circularly polarizing plate is used for preventing reflection of external light. Conventionally, iodine has been widely used as a dichroic material in these polarizing plates (polarizing elements). However, since iodine has a high sublimation property, when it is used for a polarizing plate, its heat resistance and light resistance are not sufficient, and the polarization characteristics deteriorate over time.

  Therefore, for example, as described in Patent Document 1 and Non-Patent Documents 1 and 2, an anisotropic dye film as a polarizing film using an organic dye as a dichroic substance (dichroic dye) has been studied. ing.

  The dichroic dyes described in these documents form a lyotropic liquid crystal phase in a solvent such as water or alcohol, and can be easily aligned by an external field such as an alignment substrate, a flow field, an electric field, or a magnetic field. . For example, if Brillant Yellow (C.I. Direct Yellow 4) is used, a positive dichroic dye film, Methylene Blue (C.I. Basic Blue 9) or Amaranth (C.I. Food Red 9) is used. It is known that a dichroic dye film can be obtained.

  However, these dichroic dye films have a drawback of low dichroism. This is also a problem with schlieren defects peculiar to liquid crystals as described in these documents, but film defects due to drying strain that occurs when the coating film is dried in the film formation process of the dye film by the wet film formation method. There is also a problem that light leakage is caused by cracks and cracks, resulting in a decrease in dichroism.

  On the other hand, in forming an anisotropic dye film by a wet film forming method, in order to improve the film thickness uniformity of the coating film and increase the productivity, the dye in the composition for the anisotropic dye film is used. Although it is preferable to lower the solid content concentration, lowering the solid content concentration tends to increase the above-mentioned drying strain, and rather results in lowering the dichroism.

For this reason, it has been difficult to achieve both high coating film uniformity and productivity and high dichroism in the formation of anisotropic dye films.
US Pat. No. 2,400,877 Dreyer, JF, Phys. And Colloid Chem., 1948, 52, 808., “The Fixing of Molecular Orientation” Dreyer, JF, Journal de Physique, 1969, 4, 114., “Light Polarization From Films of Lyotropic Nematic Liquid Crystals”

  The present invention provides an anisotropic dye film composition capable of forming an anisotropic dye film having high dichroism and high coating uniformity with high productivity, and an anisotropic dye film composition comprising: It is an object of the present invention to provide a high dichroic anisotropic dye film formed using the same and a polarizing element using the anisotropic dye film.

  As a result of intensive studies, the present inventors have found that a composition for an anisotropic dye film containing a dye and capable of forming a lyotropic liquid crystal phase, having a relaxation elasticity at a temperature of 5 ° C. and 0.01 seconds after strain application. By using an anisotropic dye film composition in which the time until the rate G decreases to 1/10 is 0.1 second or less, an anisotropic dye having high coating uniformity and high dichroism The present inventors have found that a film can be formed with high efficiency and have reached the present invention.

（上記式中、Ｘ^１は、水素原子またはスルホ基を表す。Ａ^１は、置換基を有していてもよいフェニル基、置換基を有していてもよいナフチル基または置換基を有していてもよい芳香族複素環基を表す。Ｂ^１は、置換基を有していてもよい芳香族炭化水素基または置換基を有していてもよい芳香族複素環基を表す。ｎは、１または２を表す。） Accordingly, the composition for anisotropic dye film of the present invention is a composition for anisotropic dye film that contains a dye whose free acid form is represented by the following formula and can form a lyotropic liquid crystal phase, Containing 0.9 equivalents or more and 0.99 equivalents or less of a cation and 0.02 equivalents or more and 0.1 equivalents or less of a strongly acidic anion with respect to the acidic group of the dye, temperature 5 ° C., 0.01 after applying strain The time until the relaxation modulus G after 1 second is reduced to 1/10 is 0.1 seconds or less.

(In the above formula, X ¹ represents a hydrogen atom or a sulfo group. A ¹ has a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a substituent. B ¹ represents an optionally substituted aromatic heterocyclic group, B ¹ represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and n represents Represents 1 or 2.)

  A coating film obtained by forming a film by the wet film forming method using the composition for anisotropic dye film of the present invention is uniform and excellent in productivity. For this reason, an anisotropic dye film that exhibits high dichroism and high coating film uniformity can be formed with high productivity. The reason is estimated as follows.

  When a thin film of lyotropic liquid crystal containing a dye is applied and dried, the dye concentration increases and the interaction between the dye aggregates becomes strong, so that the relative position of the aggregates in the solution is ordered. Such order can be observed by observing an X-ray diffraction pattern as shown in Non-Patent Document 3, for example. When strain is applied to a liquid having order at the relative position of such an aggregate, the relative position changes, generating elastic stress to return to the original state, and the entire aggregate flows to return to the equilibrium position. The leverage is relieved. It is shown in Non-Patent Document 4 that such a relaxation process of liquid crystal requires a longer time than the translation and rotation relaxation time of one aggregate.

  When a lyotropic liquid crystal thin film oriented by an external field is applied and dried, the film surface is distorted, resulting in defects similar to the defects shown in Non-Patent Document 5 and cracks in the film, which may significantly impair the properties of the coating film. However, if the relaxation time for returning the position of the aggregate to the equilibrium state is sufficiently shorter than the drying time of the coating film, it is presumed that such defects do not occur.

  In order to shorten this relaxation time, it is desirable that the order of the relative position of the aggregate is low. The order of the relative position of the aggregate is evaluated by the half width of the X-ray diffraction peak shown in Non-Patent Document 3. In order to lower the order of the relative positions of the aggregates, salt is added to increase the ionic strength or to lower the neutralization degree of the dye to moderately suppress the electrical repulsion between the aggregates. This is very important. If the neutralization degree of the dye is excessively lowered, the dye will be precipitated. Moreover, when salt is added excessively, salt precipitates on the coating film and decreases the degree of orientation of the dye.

Based on such a theory, the present inventors assumed that the relaxation time G when the concentration was increased by drying was short, and that the relaxation modulus G after 0.01 seconds after applying the strain was 10 ° C. An attempt was made to use an anisotropic dye film composition whose time to decrease to a fraction of 0.1 second or less, and it was confirmed that defects and cracks in the coating film could be suppressed. The present inventors have found that an anisotropic dye film having a high dichroism and a high dichroism can be formed with high efficiency.
J. Lydon, “Chromonics” in “Handbook of Liquid Crystals vol.2B: Low Molecular Weight Liquid Crystals II”, p.981, edited by D.Demus, J.Goodby, GWGray, H.-W.Spiess and V. Vill, Wiley-VCH, (1998). PGde Gennes and J. Prost, “Dynamical Properties of Smectics and Columnar Phases” in “The Physics of Liquid Crystals” p.408, Clarendon Press. Oxford, (1993) M. Gharbia, M. Cagnon and G. Durand, “Column undulation instability in a discotic liquid crystal”, J. Physique Lett., 46 (1985), L683.

  Such a composition for an anisotropic dye film of the present invention is particularly useful for forming an anisotropic dye film by a wet film forming method.

  Further, the composition for anisotropic dye film of the present invention has a cation of 0.9 equivalent to 0.99 equivalent and a strong acid anion of 0.02 equivalent to 0.1 equivalent with respect to the acidic group of the dye. It is preferable to contain.

（上記式中、Ｘ^１は、水素原子またはスルホ基を表す。Ａ^１は、置換基を有していてもよいフェニル基、置換基を有していてもよいナフチル基または置換基を有していてもよい芳香族複素環基を表す。Ｂ^１は、置換基を有していてもよい芳香族炭化水素基または置換基を有していてもよい芳香族複素環基を表す。ｎは、１または２を表す。） The anisotropic dye film of the present invention is formed using such an anisotropic dye film composition of the present invention.
The anisotropic dye film of the present invention also comprises a dye having a free acid form represented by the following formula, a cation of 0.9 equivalent to 0.99 equivalent to the acidic group of the dye, and a strongly acidic anion 0.02 equivalents or more and 0.1 equivalents or less.

(In the above formula, X ¹ represents a hydrogen atom or a sulfo group. A ¹ has a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a substituent. B ¹ represents an optionally substituted aromatic heterocyclic group, B ¹ represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and n represents Represents 1 or 2.)

  The polarizing element of the present invention uses such an anisotropic dye film of the present invention.

  According to the present invention, an anisotropic dye film having high coating film uniformity, few defects, and high dichroism can be formed with high productivity. A polarizing element having excellent light resistance and excellent polarization performance is provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. However, the description of constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents.

  The anisotropic dye film referred to in the present invention differs from the electromagnetic properties in any two directions selected from a total of three directions in the three-dimensional coordinate system of the thickness direction of the dye film and any two orthogonal planes. It is a dye film having anisotropy. Examples of electromagnetic properties include optical properties such as absorption and refraction, and electrical properties such as resistance and capacitance. Examples of the film having optical anisotropy such as absorption and refraction include a linearly polarizing film, a circularly polarizing film, a retardation film, and a conductive anisotropic film.

  The anisotropic dye film of the present invention is preferably used for a polarizing film, a retardation film, and a conductive anisotropic film, and more preferably used for a polarizing film.

[Anisotropic Dye Film Composition]
First, the anisotropic dye film composition of the present invention will be described.
<Temperature until the relaxation modulus G decreases to 1/10 at a temperature of 5 ° C. and 0.01 seconds after applying the strain>
The composition for anisotropic dye film of the present invention is a composition for anisotropic dye film containing a dye and capable of forming a lyotropic liquid crystal phase, at a temperature of 5 ° C., 0.01 seconds after applying strain. The time until the relaxation elastic modulus G decreases to 1/10 (hereinafter sometimes referred to as “relaxation elastic modulus decrease time”) is 0.1 second or less.

  In the present invention, the relaxation elastic modulus of the composition for anisotropic dye film is the relaxation elasticity measured under the following conditions using the Stress Relaxation mode of the viscoelasticity measuring device ARES viscoelasticity measurement system (manufactured by Rheometric Scientific). Say rate. Further, it may be measured by an apparatus equivalent to this apparatus.

(Measurement method of relaxation modulus)
As the measurement jig, a cone plate having a diameter of 50 mm is used if the relaxation modulus of the sample (composition for anisotropic dye film) is 100 dyn / cm ² or less, and if it exceeds 100 dyn / cm ² , a diameter of 25 mm is used. Use a cone plate. In order to keep the sample temperature at 5 ° C. and eliminate the history when setting the sample, a pre-shear at a shear rate of 1000 s ⁻¹ is applied for 10 seconds before the measurement is started, and the measurement is performed at a strain of 10% after being left for 1 minute. .

  The composition for an anisotropic dye film of the present invention has a composition in which the time during which the relaxation modulus G after 0.01 seconds from the application of strain is reduced to 1/10 is 0.1 seconds or less. It is a thing. The relaxation elastic modulus decrease time is preferably shorter, more preferably 0.07 seconds or less, still more preferably 0.05 seconds or less. When the relaxation elastic modulus decrease time exceeds 0.1 seconds, an anisotropic dye film having high coating film uniformity and high dichroism cannot be obtained with high production efficiency.

  The composition for anisotropic dye film of the present invention specifically contains at least a dye and a solvent, and as described in Non-Patent Document 3, specifically, the dye is polar such as water or alcohol. The composition is capable of forming an aggregate in a solvent and forming a lyotropic liquid crystal phase from the shape anisotropy of the aggregate.

<Dye>
The dye used in the present invention is preferably soluble in water or an organic solvent, and particularly preferably water-soluble, for use in the wet film-forming method described later. The composition of the present invention can be obtained by selecting a dye.

  The dye used in the present invention is preferably in a free state that does not take a salt form, and has a molecular weight of 200 or more, particularly 300 or more, and 1500 or less, particularly 1200 or less.

  Specific examples of the dye include condensed polycyclic and azo dyes, but are not limited thereto. For example, U.S. Pat. No. 2,400,877, Dreyer, JF, Phys. And Colloid Chem., 1948, 52, 808., “The Fixing of Molecular Orientation”, Dreyer, JF, Journal de Physique, 1969, 4, 114., “Light Polarization From Films of Lyotropic Nematic Liquid Crystals”, and J. Lydon, “Chromonics” in “Handbook of Liquid Crystals Vol.2B: Low Molecular Weight Liquid Crystals II”, D. Demus, J. Goodby , GWGray, HWSpiessm V. Ville ed., Willey-VCH, P. 981-1007, (1998), etc. can be used.

  Of these, azo dyes are preferred. Among the azo dyes, disazo dyes or trisazo dyes are preferable. For polarizing film applications, γ acid-based or RR acid-based azo dyes are preferable in that they have absorption evenly in the entire visible light range.

In the present invention, a dye whose free acid form is represented by the following formula is particularly preferable.

In the above formula, X ¹ represents a hydrogen atom or a sulfo group. A ¹ represents a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. B ¹ represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. n represents 1 or 2.

When A ¹ is an aromatic heterocyclic group, examples of the hetero atom of the aromatic heterocyclic group include a nitrogen atom and a sulfur atom. The aromatic heterocyclic group having a nitrogen atom reduces the liquid crystallinity expression density. Therefore, it is preferable. Specific examples of the aromatic heterocyclic group include a pyridyl group, a quinolyl group, a thiazolyl group, and a benzothiazolyl group, and a pyridyl group is preferable.

When B ¹ is an aromatic hydrocarbon group, specific examples include a phenylene group or a naphthylene group. The phenylene group is preferably a 1,4-phenylene group, and the naphthylene group is preferably a 1,4-naphthylene group in order to exhibit the above interaction. If B ¹ is an aromatic heterocyclic group, the A ¹ and the like are divalent example in an aromatic heterocyclic group.

Examples of the substituent that the phenyl group, naphthyl group or aromatic heterocyclic group as A ¹ or the aromatic hydrocarbon group or aromatic heterocyclic group as B ¹ may have include an alkyl group, an alkoxy group, an amino group Group, acyl group, carbamoyl group, carboxy group, sulfo group, hydroxyl group and cyano group.

  The dye used in the present invention is particularly a dye represented by the following structural formula (I-1) (hereinafter sometimes referred to as “dye No. (I-1)”), and the following structural formula (I-2). (Hereinafter sometimes referred to as “Dye No. (I-2)”), and a dye represented by the following structural formula (II-1) (hereinafter referred to as “Dye No. (II-1)”. ) ”, A dye represented by the following structural formula (III-1) (hereinafter sometimes referred to as“ dye No. (III-1) ”), and the following structural formula (III- 2) (hereinafter sometimes referred to as “Dye No. (III-2)”), and a dye represented by the following structural formula (IV-1) (hereinafter referred to as “Dye No. (IV)”. -1) "), etc.) are preferred. These dyes may be in a salt form as described later.

These dyes can be produced according to a method known per se.
For example, the dye No. (I-1) can be produced by the following steps (A) and (B).

(A) From 4-aminobenzonitrile and 8-amino-2-naphthalenesulfonic acid (1,7-Cleves acid), a conventional method (for example, Yutaka Hosoda, “New dye chemistry” (December 21, 1973, In accordance with (published by Gihodo), see page 396, page 409), a monoazo compound is produced through a diazotization and coupling process.
(B) Similarly, diazotize the obtained monoazo compound by a conventional method, carry out a coupling reaction with 7-amino-1-naphthol-3,6-disulfonic acid (RR acid), and salt out with sodium chloride. The target dye No. (I-1) is obtained.

  In the composition for an anisotropic dye film of the present invention, the dyes as described above can be used alone, but two or more of these may be used in combination, and the above-mentioned examples are provided so as not to lower the orientation. It can also be used by mixing with a dye other than the dye, whereby an anisotropic dye film having various hues can be produced.

  When other pigments are blended, examples of preferred pigments for blending include C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 34, C.I. I. Direct Yellow 86, C.I. I. Direct Yellow 142, C.I. I. Direct Yellow 132, C.I. I. Acid Yellow 25, C.I. I. Direct Orange 39, C.I. I. Direct Orange 72, C.I. I. Direct Orange 79, C.I. I. Acid Orange 28, C.I. I. Direct Red 39, C.I. I. Direct Red 79, C.I. I. Direct Red 81, C.I. I. Direct Red 83, C.I. I. Direct Red 89, C.I. I. Acid Red 37, C.I. I. Direct Violet 9, C.I. I. Direct Violet 35, C.I. I. Direct Violet 48, C.I. I. Direct Violet 57, C.I. I. Direct Blue 1, C.I. I. Direct Blue 67, C.I. I. Direct Blue 83, C.I. I. Direct Blue 90, C.I. I. Direct Green 42, C.I. I. Direct Green 51, C.I. I. Direct Green 59, Alizarin Red S Monohydrate, Acid Blue 45, Acid Green 25, Alizarin Blue Black B, Acid Blue 25, Anthraquinone-2-sulfonic acid, Quinalizarin, Anthraquinone-1,5-disulfonic acid sodium salt, Acid Violet 34, Acid Green 27, Acid Blue 40, Acid Blue 80, Alizarin Safari SE, Alizarin Astrol, Reactive Blue 5, Reactive Blue 19, Reactive Blue 114 Acid Violet 42, Fast Violet B and the like.

Among these dyes, the dye having an acidic group may be used as it is in its free acid form, or a part of the acidic group may be in a salt form. Further, a salt-type dye and a free acid-type dye may be mixed. Moreover, when it is obtained in a salt form at the time of production, it may be used as it is or may be converted into a desired salt form. As the salt-type exchange method, a known method can be arbitrarily used, and examples thereof include the following methods.
1) A strong acid such as hydrochloric acid is added to an aqueous solution of a dye obtained in a salt form, the dye is acidified in the form of a free acid, and then the dye is added with an alkaline solution having a desired counter ion (for example, an aqueous lithium hydroxide solution). A method of neutralizing acidic groups and salt exchange.
2) A method of performing salt exchange in the form of a salting-out cake by adding a large excess of a neutral salt (eg, lithium chloride) having a desired counter ion to an aqueous dye solution obtained in a salt form.
3) An aqueous solution of a dye obtained in a salt form is treated with a strongly acidic ion exchange resin, and the dye is acidified in the form of a free acid, and then an alkali solution having a desired counter ion (for example, an aqueous lithium hydroxide solution). To neutralize the acidic group of the dye and exchange the salt.
4) A method of performing salt exchange by allowing an aqueous solution of a dye obtained in a salt form to act on a strongly acidic ion exchange resin previously treated with an alkaline solution having a desired counter ion (for example, an aqueous lithium hydroxide solution).

  Examples of the salt type of the exemplified dye include salts of alkali metals such as Na, Li and K, ammonium salts which may be substituted with alkyl groups or hydroxyalkyl groups, and organic amine salts. Examples of the organic amine include a lower alkyl amine having 1 to 6 carbon atoms, a hydroxy substituted lower alkyl amine having 1 to 6 carbon atoms, a carboxy substituted lower alkyl amine having 1 to 6 carbon atoms, and the like. In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed.

  In the present invention, if the dye association length in the composition for anisotropic dye film can be made sufficiently long, it is possible to prevent the orientation of the obtained anisotropic film from being lowered, which is more preferable. In order to increase the orientation of the anisotropic dye film, the length of the dye aggregate in the composition for an anisotropic dye film of the present invention is preferably 5 nm or more. Further, it is preferable to provide sufficient orientation when orienting in the external field, whereby the orientation of the obtained anisotropic dye film can be improved.

  The length of the dye aggregate in the composition for anisotropic dye film is, for example, DJEdwards et.al., “Aggregation and lyotropic liquid crystal formation of anionic azo dyes for textile fibers”, in “Physico-Chemical Principles of Color Chemistry” "P. 83, edited by ATPeters and HS Freeman, Blackie Academic & Professional, (1996).

<solvent>
As the solvent used in the composition for an anisotropic dye film of the present invention, water, a water-miscible organic solvent, or a mixture thereof is suitable. Specific examples of the organic solvent include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, glycols such as ethylene glycol and diethylene glycol, cellosolves such as methyl cellosolve and ethyl cellosolve, or a mixture of two or more kinds. Can be mentioned.

<Dye concentration>
When the anisotropic dye film composition of the present invention is a solution containing a solvent as described above, the concentration of the dye in the anisotropic dye film composition depends on the film formation method described later, It is usually 0.01% by weight or more, particularly 0.1% by weight or more, and usually 50% by weight or less, and particularly preferably 30% by weight or less. If the dye concentration is too low, sufficient dichroism cannot be obtained in the anisotropic dye film, and if it is too high, the dye may be precipitated.

<Cation, anion>
The composition for an anisotropic dye film of the present invention has a cation of 0.9 equivalent or more and 0.99 equivalent or less and a strongly acidic anion of 0.02 equivalent or more and 0.1 relative to the acidic group of the dye in the composition. It is preferable that it contains below equivalent.
Even when the cation and the anion are contained in this range, the time until the relaxation elastic modulus G decreases to 1/10 of the temperature 5 ° C. and 0.01 seconds after applying the strain is 0.1 seconds or less. An anisotropic dye film composition can be obtained.

Examples of the cation include alkali metal ions such as lithium, sodium, potassium, rubidium, and cesium, amine ions such as ammonia, alkylamine, basic amino acid, and hydroxyamine, or pyridinium ions. These may be used alone or in combination of two or more.
These cations include those forming a salt form with the acidic group of the dye.

  Examples of the strongly acidic anion include monovalent ions such as hydrochloric acid, nitric acid, and perchloric acid, divalent ions such as sulfuric acid, and trivalent ions such as phosphoric acid. These may be used alone or in combination of two or more.

The difference between the cation content and the strongly acidic anion content in the anisotropic dye film composition of the present invention is preferably 0.9 equivalents or more and 0.95 equivalents or less with respect to the acidic group of the dye. .
When there are more cations than the said range, there exists a possibility of producing the defect and crack by dry distortion. In addition, if there are many strong acid anions, salts of cations and strong acid anions may precipitate to disturb the orientation, and if there are more, the solubility of the dye may be impaired.

  Specifically, when preparing a salt + of a dye, a dye having a neutralization degree of about 50 to 80% and a dye having a neutralization degree of 100% are prepared, and these dyes and a strong acid or By blending a strong acid salt and water, a composition containing such a cation and a strong acidic anion can be obtained.

<Additive>
The composition for an anisotropic dye film of the present invention may contain additives such as a surfactant, if necessary, in order to improve wettability to a substrate, coatability, and the like. As the surfactant, any of anionic, cationic and nonionic properties can be used. The concentration of the additive is sufficient to obtain the desired effect and does not inhibit the orientation of the dye molecules. The concentration in the composition for anisotropic dye film is usually 0.05% by weight or more, and 0.0. 5% by weight or less is preferable.

  In addition, for the purpose of suppressing instability such as salt formation and aggregation of the dye in the composition for anisotropic dye film of the present invention, a pH adjuster such as a generally known acid or alkali is used. The pH may be adjusted by adding either before or after mixing of the constituent components.

  Furthermore, as additives other than those described above, known additives described in “Additive for Coating”, Edited by J. Bieleman, Willey-VCH (2000) can also be used.

  Further, as an additive, a compound having two or more groups selected from the group consisting of an acidic group, a basic group and a neutral group, and at least one of the two or more groups being a basic group It is also preferable to add.

  An acidic group and a basic group are functional groups having a pka of less than 7 and 7 or more, respectively, in an aqueous solution to which an inert supporting electrolyte is added in an amount of 0.1 to 3 mol / dm. A neutral group is one having no dissociation multiplier. Chemical Handbook Basics II, p. As described in 331 (Edited by The Chemical Society of Japan, Maruzen), pka is a logarithmic value of the reciprocal of the concentration acid dissociation constant ka, that is, -log ka.

  Examples of the acidic group include a sulfo group, a carboxyl group, and a phosphoric acid group. As the basic group, amino group, sulfonium group, pyrrole group, 3-pyrroline group, pyrrolidine group, pyrazole group, 2-pyrazolin group, pyrazolidine group, imidazole group, 1,2,3-triazole group, 1,2, 4-triazole group, pyridine group, pyridazine group, piperidine group, pyrazine group, piperazine group, pyrimidine group, triazine group and the like can be mentioned. Examples of the neutral group include a hydroxyl group, an amine oxide group, a sulfoxide group, and a phosphine oxide group. The above group may further have a substituent as long as it does not greatly change the characteristics of the composition for an anisotropic dye film of the present invention.

  A part or all of the acidic group and the basic group may have a salt form. Examples of the salt type of the basic group include salts of inorganic acids such as hydrochloric acid and sulfuric acid, and salts of organic acids such as acetic acid and formic acid. Examples of the salt type of the acidic group include salts of alkali metals such as Na, Li, and K, ammonium salts that may be substituted with alkyl groups or hydroxyalkyl groups, and salts of organic amines. In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed.

  The molecular weight of the compound is usually preferably 60 or more and 75 or more, more preferably 100 or more, particularly preferably 140 or more, preferably 300 or less, more preferably 250 or less, and particularly preferably 200 or less.

  The compound is preferably a compound having 1 or more carbon atoms, more preferably 3 or more, particularly preferably 6 or more, preferably 15 or less, more preferably 12 or less, and particularly preferably 10 or less.

From the viewpoints of molecular orientation, cohesiveness and the like, the basic group of the compound may be 1 or more, preferably 2 or more, 5 or less, and more preferably 4 or less. In addition, when this compound does not have a neutral group and an acidic group but has only a basic group, the number of basic groups is preferably 3 or more, preferably 5 or less, and more preferably 4 or less. .
When the compound has an acidic group, the acidic group may be 1 or more, preferably 4 or less, more preferably 3 or less. The relative ratio of the number of basic groups and acidic groups in the compound is preferably 1.3 or more, and more preferably 4 or less.
When the compound has a neutral group, the neutral group may be 1 or more, and the number thereof is not particularly limited, but is usually 8 or less, preferably 6 or less.
When the compound has two or more basic groups, acidic groups, and neutral groups, the two or more groups may be the same group or different groups.

The compound may be a chain compound or a cyclic compound.
As the compound, amines are preferable, and amino acids, betaines, hydroxyamines, and cyclic compounds having a basic group are particularly preferable.

Amino acids are classified into neutral amino acids, acidic amino acids, and basic amino acids based on the number and nature of acidic groups and basic groups.
Specific examples of neutral amino acids include glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, tryptophan, serine, threonine, proline, 4-hydroxyproline, cysteine, cystine, methionine, asparagine, glutamine, β-alanine, citrulline , Creatine, kynurenine and the like. Among these, phenylalanine, asparagine, 4-hydroxyproline and β-alanine are particularly preferable.
Specific examples of acidic amino acids include aspartic acid and glutamic acid, and among these, aspartic acid and glutamic acid are particularly preferable.
Specific examples of basic amino acids include lysine, arginine, histidine and the like.

  The molecular weight of the amino acid is usually 60 or more, preferably 75 or more, and usually 300 or less, preferably 250 or less. If the molecular weight of the amino acid is too large, the molecular size is large and the orientation of the dye molecules may be disturbed. Conversely, if the molecular weight is too small, the effect of fixing the orientation of the dye molecules may not be sufficiently exhibited.

  Betaines include carboxyalkyl trialkyl ammonium hydroxide, carboxyalkyl pyridinium hydroxide, sulfoalkyl trialkyl ammonium hydroxide, sulfoalkyl pyridinium hydroxide, phosphoalkyl trialkyl ammonium hydroxide, phosphoalkyl pyridinium water. Examples thereof include oxides and derivatives of these compounds, among which carboxymethyltrimethylammonium hydroxide and sulfopropylpyridinium hydroxide are preferable.

  The molecular weight of betaines is usually 60 or more, preferably 75 or more, and usually 300 or less, preferably 250 or less. If the molecular weight of the betaines is too large, the molecular size may be large and the orientation of the dye molecules may be disturbed. Conversely, if the molecular weight is too small, the orientation fixing effect of the dye molecules may not be sufficiently exhibited.

  Examples of hydroxyamines include aminoalkyl alcohols, diaminoalkyl alcohols, aminoalkyl diols, diaminoalkyl diols, etc. Among these, aminopropane diols are preferred.

  The molecular weight of hydroxyamines is usually 60 or more, preferably 75 or more, and usually 300 or less, preferably 250 or less. If the molecular weight of the hydroxyamines is too large, the molecular size is large, which may disturb the orientation of the dye molecules. Conversely, if the molecular weight is too small, the effect of fixing the orientation of the dye molecules may not be sufficiently exhibited.

  Examples of basic cyclic compounds include aminopyridine, diaminopyridine, triaminopyridine, aminopyridazine, diaminopyridazine, triaminopyridazine, aminopyrimidine, diaminopyrimidine, triaminopyrimidine, aminopyrazine, diaminopyrazine, triaminopyrazine, Aminotriazine, diaminotriazine, triaminotriazine, etc. are mentioned, and among these, triaminopyrimidine is preferable.

  The molecular weight of the cyclic compound having a basic group is usually 60 or more, preferably 75 or more, and usually 300 or less, preferably 250 or less. If the molecular weight of the cyclic compound having a basic group is too large, the molecular size may be large and the orientation of the dye molecule may be disturbed. On the other hand, if the molecular weight is too small, the orientation fixing effect of the dye molecule may not be sufficiently exhibited.

  Such compounds as described above may be used alone or in combination of two or more of the same or different compounds. In addition, for example, optical isomers present in amino acids may be used alone or both may be included. Moreover, a salt type compound and a free compound may be included, and different salt type compounds may be included.

  The composition of the present invention can also be obtained by adding the above additives to the composition. For example, the composition of the present invention can be obtained by further adding the above-mentioned additives even if the composition specified by the present invention is not obtained by using only the dye and the solvent.

[Anisotropic dye film]
Next, the anisotropic dye film of the present invention formed using such an anisotropic dye film composition of the present invention will be described.

  According to the composition for an anisotropic dye film of the present invention, an anisotropic dye film having high dichroism and high coating uniformity can be formed with high productivity. The anisotropic dye film of the present invention formed using this anisotropic dye film composition is an industrially useful dye film that exhibits high dichroism and is excellent in stability.

  The anisotropic dye film of the present invention exhibits a high dichroic ratio, but the dichroic ratio is preferably 5 or more, more preferably 10 or more, and particularly preferably 15 or more.

  Such an anisotropic dye film of the present invention is produced by a dry film formation method or a wet film formation method using the anisotropic dye film composition of the present invention. In the present invention, since the composition for an anisotropic dye film containing a dye exhibits liquid crystallinity, it is preferable to employ a wet film forming method.

  As a dry film-forming method, a method of forming a polymer polymer into a film and then dyeing it with the composition for anisotropic dye film of the present invention, or an anisotropic solution of the present invention in a solution of the polymer polymer Examples thereof include a method of stretching an unstretched film obtained by adding a dye film composition and forming a film after dyeing the stock solution. The said dyeing | staining, film-forming, and extending | stretching can be performed by the following general method.

  In the dye bath to which the composition for anisotropic dye film of the present invention and, if necessary, an inorganic salt such as sodium chloride and bow glass, and a dyeing assistant such as a surfactant are added, usually at 20 ° C. or higher, preferably 30 ℃ or higher, usually 80 ℃ or less, preferably 50 ℃ or less, usually 1 minute or more, preferably 3 minutes or more, usually 60 minutes or less, preferably 20 minutes or less. Treat with boric acid and dry. Alternatively, the high molecular weight polymer is dissolved in water and / or a hydrophilic organic solvent such as alcohol, glycerin, dimethylformamide, etc., and the composition for anisotropic dye film of the present invention is added to perform stock solution dyeing. Is formed into a dyed film by casting, solution coating, extrusion, or the like. The concentration of the polymer to be dissolved in the solvent varies depending on the type of polymer, but is usually 5% by weight or more, preferably about 10% by weight or more, and usually 30% by weight or less, preferably 20% by weight. It is about the following. The concentration of the dye dissolved in the solvent is usually 0.1% by weight or more, preferably about 0.8% by weight or more, usually 5% by weight or less, preferably 2.5% by weight based on the polymer. % Or less.

  The unstretched film obtained by dyeing and forming a film as described above is stretched in a uniaxial direction by an appropriate method. By performing the stretching treatment, the dye molecules are oriented and dichroism is expressed. As a method of stretching uniaxially, there are a method of stretching by a wet method, a method of stretching by a dry method, a method of compressing and stretching between rolls by a dry method, etc., and any method is used. May be. The draw ratio is 2 to 9 times, but when polyvinyl alcohol and its derivatives are used as the polymer, a range of 2.5 to 6 times is preferable. After the stretching and orientation treatment, boric acid treatment is performed for the purpose of improving the water resistance and the degree of polarization of the stretched film. The boric acid treatment improves the light transmittance and the degree of polarization of the anisotropic dye film. The conditions for the boric acid treatment vary depending on the type of the hydrophilic polymer used and the dye, but in general, the boric acid concentration is usually 1% by weight or more, preferably about 5% by weight or more, usually 15%. It is about 10% by weight or less, preferably about 10% by weight or less. Further, the treatment temperature is usually 30 ° C. or higher, preferably 50 ° C. or higher and usually 80 ° C. or lower. When the boric acid concentration is less than 1% by weight or when the treatment temperature is less than 30 ° C., the treatment effect is small, and when the boric acid concentration exceeds 15% by weight or the treatment temperature exceeds 80 ° C. The anisotropic dye film becomes fragile and is not preferable.

  The film thickness of the anisotropic dye film obtained by such a dry film forming method is preferably 10 μm or more, particularly 30 μm or more, and 200 μm or less, particularly 100 μm or less.

  On the other hand, as a wet film formation method, after preparing the composition for anisotropic dye film of the present invention as a coating liquid, applying it to various substrates such as glass plates and drying, orienting and laminating the dye, etc. A well-known method is mentioned. As coating methods, Yuji Harasaki, “Coating Engineering” (Asakura Shoten Co., Ltd., published on March 20, 1971) pp. 253-277 and Kunihiro Ichimura “Creation and Application of Molecular Cooperative Materials” (CMC Co., Ltd.) (Published, published on March 3, 1998). For example, a known method described in pages 118 to 149, for example, a spin coating method, a spray coating method, a bar coating method, a roll on a substrate that has been previously subjected to orientation treatment. It may be applied by a coating method, a blade coating method or the like. In this case, if the dye concentration in the composition for anisotropic dye film is too low, sufficient dichroism cannot be obtained, and if it is too high, film formation becomes difficult. The dye concentration in the anisotropic dye film composition in the wet film formation method is preferably 0.1% by weight or more, particularly preferably 1% by weight or more, preferably 50% by weight or less, particularly preferably 30% by weight. It is as follows. The temperature during application is preferably 0 ° C. or more and 80 ° C. or less, and the humidity is preferably about 10% RH or more and 80% RH or less.

  Moreover, the temperature at the time of drying of a coating film becomes like this. Preferably it is 0 degreeC or more and 120 degrees C or less, Humidity becomes like this. Preferably it is about 10% RH or more and 80% RH or less.

  When forming an anisotropic dye film on a substrate by a wet film forming method, the anisotropic dye film is usually a film thickness after drying, preferably 50 nm or more, more preferably 100 nm or more, preferably 50 μm or less, More preferably, it is 20 micrometers or less, More preferably, it is 1 micrometer or less.

  In addition, as a base material used for a wet film-forming method, glass, a triacetate, an acryl, polyester, a triacetyl cellulose, or a urethane type film etc. are mentioned. Further, in order to control the orientation direction of the dichroic dye, the surface of the substrate is publicly known as described in “Liquid Crystal Handbook” (Maruzen Co., Ltd., issued on October 30, 2000), pages 226 to 239. The orientation treatment layer may be applied by the method.

  An anisotropic dye film of a dichroic dye obtained by a dry film forming method or a wet film forming method is used with a protective layer provided if necessary. This protective layer is formed by lamination with a transparent polymer film such as triacetate, acrylic, polyester, polyimide, triacetyl cellulose, or urethane film, and is put to practical use.

  Further, when the anisotropic dye film composition of the present invention is used as a polarizing filter or the like in various display elements such as LCDs and OLEDs, the anisotropic property of the present invention is directly applied to the electrode substrate constituting these display elements. A base material on which an anisotropic dye film is formed or an anisotropic dye film of the present invention may be used as a constituent member of these display elements.

  The anisotropic dye film of the present invention has a cation of 0.9 equivalents or more and 0.99 equivalents or less and a strongly acidic anion of 0.02 equivalents or more and 0.000 equivalents or less with respect to the acidic group of the dye in the anisotropic dye film. 1 equivalent or less.

Examples of the cation include alkali metal ions such as lithium, sodium, potassium, rubidium, and cesium, amine ions such as ammonia, alkylamine, basic amino acid, and hydroxyamine, or pyridinium ions. These may be used alone or in combination of two or more.
These cations include those forming a salt form with the acidic group of the dye.

  Examples of the strongly acidic anion include monovalent ions such as hydrochloric acid, nitric acid, and perchloric acid, divalent ions such as sulfuric acid, and trivalent ions such as phosphoric acid. These may be used alone or in combination of two or more.

The difference between the cation content and the strongly acidic anion content in the anisotropic dye film of the present invention is preferably 0.9 equivalents or more and 0.95 equivalents or less with respect to the acidic group of the dye.
When there are more cations than the said range, there exists a possibility of producing the defect and crack by dry distortion. In addition, if there are many strong acid anions, salts of cations and strong acid anions may precipitate to disturb the orientation, and if there are more, the solubility of the dye may be impaired.

  Such an anisotropic dye film is different in that a cation is contained in an amount of 0.9 equivalents or more and 0.99 equivalents or less and a strongly acidic anion is contained in an amount of 0.02 equivalents or more and 0.1 equivalents or less with respect to the acidic group of the dye. It may be formed using a composition for an isotropic dye film, or may be obtained by other methods.

  The anisotropic dye film of the present invention functions as a polarizing film that obtains linearly polarized light, circularly polarized light, elliptically polarized light, etc. by utilizing the anisotropy of light absorption, and also includes a film forming process and a composition containing a substrate and a dye Thus, it is possible to make it functional as various anisotropic films such as refraction anisotropy and conduction anisotropy, and it is possible to obtain various kinds of polarizing elements that can be used for various purposes.

[Polarizing element]
The polarizing element of the present invention uses the above-described anisotropic dye film of the present invention, but it may be a polarizing element consisting only of an anisotropic dye film, or an anisotropic dye film on a substrate. It may be a polarizing element. A polarizing element having an anisotropic dye film on a substrate is called a polarizing element including a base material.

  When the anisotropic dye film of the present invention is formed on a substrate and used as a polarizing element, the formed anisotropic dye film itself may be used. In addition to the protective layer as described above, an adhesive layer Or a layer having an optical function such as an antireflection layer, an alignment film, a function as a retardation film, a function as a brightness enhancement film, a function as a reflection film, a function as a transflective film, a function as a diffusion film, etc. Layers having various functions may be laminated by a wet film formation method or the like, and used as a laminate.

  These layers having optical functions can be formed, for example, by the following method.

  The layer having a function as a retardation film is subjected to, for example, a stretching process described in Japanese Patent No. 2841377, Japanese Patent No. 3094113, or a process described in Japanese Patent No. 3168850. Can be formed.

  The layer having a function as a brightness enhancement film may be formed by forming a fine hole by a method as described in, for example, Japanese Patent Application Laid-Open Nos. 2002-169025 and 2003-29030, or the center of selective reflection. It can be formed by overlapping two or more cholesteric liquid crystal layers having different wavelengths.

  The layer having a function as a reflective film or a transflective film can be formed using a metal thin film obtained by vapor deposition or sputtering.

  The layer having a function as a diffusion film can be formed by coating the protective layer with a resin solution containing fine particles.

  The layer having a function as a retardation film or an optical compensation film can be formed by applying and aligning a liquid crystal compound such as a discotic liquid crystal compound or a nematic liquid crystal compound.

  The anisotropic dye film of the present invention can be directly formed on a high heat-resistant substrate such as glass, and only a liquid crystal display or an organic EL display can be obtained because a high heat-resistant polarizing element can be obtained. In addition, it can be suitably used for applications requiring high heat resistance, such as liquid crystal projectors and in-vehicle display panels.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded. In the following, “part” means “part by weight”.

In the following, various evaluations of the formed dye film were performed as follows.
(1) Dichroic ratio After measuring the transmittance of the anisotropic dye film with a spectrophotometer in which an iodine polarizing element is arranged in the incident optical system, the dichroic ratio was calculated by the following equation.
Dichroic ratio (D) = Az / Ay
Az = -log (Tz)
Ay = -log (Ty)
Tz: transmittance for polarized light in the direction of the absorption axis of the dye film Ty: transmittance for polarized light in the direction of the polarization axis of the dye film
(2) Defects and cracks Using a polarizing microscope Nikon Optiphot-POL, observation was performed at a quenching position using a 100 × objective lens and a 10 × eyepiece.

( Comparative Example 4 )
In 80 parts of water, the exemplified dye No. After stirring and dissolving 20 parts of the lithium salt of (I-1), it was filtered to obtain an anisotropic dye film composition.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G after measurement of the temperature of 5 ° C. and 0.01 seconds after applying the strain was 9.2 × 10 ¹ dyn / cm ² measured by the above-described method. The time until the elastic modulus G decreased to 1/10 was 0.04 seconds, which was shorter than 0.1 seconds.

Prepare a substrate in which a polyimide alignment film (film thickness of about 800 mm) is formed on a glass substrate (75 mm × 25 mm, thickness 1 mm) by a silk printing method, and has been rubbed with a cloth in advance. The anisotropic dye film composition was applied to this with an applicator having a gap of 2 μm (four-side applicator manufactured by Imoto Seisakusho Co., Ltd.) and then vacuum-dried to obtain an anisotropic dye film having a thickness of 0.4 μm. .
Defects and cracks were not observed in the obtained anisotropic dye film. The dichroic ratio at a wavelength of 550 nm was 27.

( Reference Example 1 )
In 69 parts of water, the exemplified dye No. 30 parts of lithium salt (II-1) and 1 part of 4,5,6-triaminopyrimidine sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) were stirred and dissolved and then filtered to obtain an anisotropic dye film composition.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G measured at the temperature of 5 ° C. and 0.01 seconds after applying the strain was 1.8 × 10 ⁴ dyn / cm ^{2 as} measured by the method described above. The time until the rate G decreased to 1/10 was 0.05 seconds, which was shorter than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
In the obtained anisotropic dye film, no defects and cracks were observed, and the dichroic ratio at a wavelength of 550 nm was 30.

(Example 1 )
To 78.94 parts of water, desalted and purified Example Pigment No. 15 parts of lithium salt of (I-1); A composition for anisotropic dye film is prepared by stirring and dissolving 5 parts of a neutralized salt of 80 mol% lithium of (I-1), 1 part of desalted and purified Aldrich Alizarin Red S and 0.06 part of lithium chloride, followed by filtration. Got.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G after measurement of the temperature of 5 ° C. and 0.01 seconds after applying the strain was 9.9 × 10 ¹ dyn / cm ² measured by the above-described method. The time until the elastic modulus G decreased to 1/10 was 0.04 seconds, which was shorter than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
Defects and cracks were not observed in the obtained anisotropic dye film. The dichroic ratio at a wavelength of 550 nm was 28.
Elemental analysis of the anisotropic dye film revealed that dye No. With respect to the acidic groups of (I-1) and alizarin red S, the total concentration of lithium and sodium as cations was 0.95 equivalent, and the concentration of chlorine as a strongly acidic anion was 0.06 equivalents.

(Example 2 )
To 78.94 parts of water, desalted and purified Example Pigment No. 16 parts of lithium salt of (I-1); Stirring and dissolving 4 parts of lithium 80 mol% neutralized salt of (I-1), desalted and refined Aldrich Alizarin Red S 0.08 part and lithium chloride, and then filtering and composition for anisotropic dye film Got.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G after measurement of the temperature of 5 ° C. and 0.01 seconds after applying the strain was 9.2 × 10 ¹ dyn / cm ² measured by the above-described method. The time until the elastic modulus G decreased to 1/10 was 0.04 seconds, which was shorter than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
Defects and cracks were not observed in the obtained anisotropic dye film. The dichroic ratio at a wavelength of 550 nm was 29.
Elemental analysis of the anisotropic dye film revealed that dye No. With respect to the acidic groups of (I-1) and alizarin red S, the total concentration of lithium and sodium as cations was 0.99 equivalent, and the concentration of chlorine as a strongly acidic anion was 0.08 equivalents.

(Example 3 )
Exemplified dye No. 1 was desalted and purified to 58.4 parts of water. Lithium salt of (III-1) 15.8 parts, the exemplified dye No. 9.2 parts of lithium 80 mol% neutralized salt of (III-1), desalted and purified the above exemplified dye No. After stirring and dissolving 1.5 parts of the sodium salt of (III-2) and 15.1 parts of a 1% by weight aqueous solution of lithium chloride, the mixture was filtered to obtain an anisotropic dye film composition.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G measured at the temperature of 5 ° C. and 0.01 seconds after applying the strain was 9.4 × 10 ² dyn / cm ^{2 as} measured by the above-described method. The time until the elastic modulus G decreased to 1/10 was 0.04 seconds, which was shorter than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
Defects and cracks were not observed in the obtained anisotropic dye film. The dichroic ratio at a wavelength of 550 nm was 28.

  Elemental analysis of this anisotropic dye film revealed that dye No. The total concentration of lithium and sodium as cations was 0.98 equivalent and the concentration of chlorine as a strongly acidic anion was 0.04 equivalent with respect to the acidic groups of (III-1) and (III-2).

(Comparative Example 1)
In 70 parts of water, 30 parts of the lithium salt of the dye compound represented by the structural formula (II-1) was stirred and dissolved, followed by filtration to obtain a pH 7 composition for anisotropic dye film.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G measured at the temperature of 5 ° C. and 0.01 seconds after applying the strain was 2.0 × 10 ⁴ dyn / cm ^{2 as} measured by the method described above. The time until the elastic modulus G decreased to 1/10 was 0.5 seconds, which was longer than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
When the obtained anisotropic dye film was observed at the extinction position of a polarizing microscope, there were periodic streak defects perpendicular to the coating direction, and cracks were formed parallel to the coating direction. Further, the dichroic ratio at a wavelength of 550 nm was 20, which was lower than the anisotropic dye films of Comparative Example 4 and Reference Example 1 .

(Comparative Example 2)
In 76.9 parts of water, the desalted and purified Example Pigment No. After stirring and dissolving 22 parts of the lithium salt (I-1) and desalted and purified Aldrich Alizarin Red S 1.1 parts, the composition for anisotropic dye film was obtained by filtration.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G at a temperature of 5 ° C. measured by the above-described method and 0.01 seconds after applying the strain was 2.1 × 10 ² dyn / cm ² , and this relaxation The time until the elastic modulus G decreased to 1/10 was 0.15 seconds, which was longer than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
When the obtained anisotropic dye film was observed at the extinction position of a polarizing microscope, there were periodic streak defects perpendicular to the coating direction, and cracks were formed parallel to the coating direction. Further, the dichroic ratio at a wavelength of 550 nm was 20, which was lower than that of the anisotropic dye films of Examples 1 and 2 .
Elemental analysis of the anisotropic dye film revealed that dye No. With respect to the acidic groups of (I-1) and alizarin red S, the total concentration of lithium and sodium as cations was 1.01 equivalent, and the concentration of chlorine as a strongly acidic anion was 0.0001 equivalents.

(Comparative Example 3)
Exemplified dye No. 1 desalted and purified to 73.5 parts of water. 25 parts of the lithium salt of (III-1), and the above exemplified dye No. After stirring and dissolving 1.5 parts of the sodium salt of (III-2), it was filtered to obtain an anisotropic dye film composition.
With respect to this anisotropic dye film composition, the relaxation elastic modulus G measured at the temperature of 5 ° C. and 0.01 seconds after applying the strain was 1.7 × 10 ⁴ dyn / cm ² measured by the method described above. The time until the elastic modulus G decreased to 1/10 was 9.4 seconds, which was longer than 0.1 seconds.

This anisotropic dye film composition was applied to the same substrate as in Comparative Example 4 by the same method to obtain an anisotropic dye film.
When the obtained anisotropic dye film was observed at the extinction position of a polarizing microscope, there were periodic streak defects perpendicular to the coating direction, and cracks were formed parallel to the coating direction. Further, the dichroic ratio at a wavelength of 550 nm was 20, which was lower than that of the anisotropic dye film of Example 3 .
Elemental analysis of this anisotropic dye film revealed that dye No. The total concentration of lithium and sodium as cations was 1.01 equivalent and the concentration of chlorine as a strongly acidic anion was 0 equivalent with respect to the acidic groups of (III-1) and (III-2).

From the results of Examples 1 to 3, Reference Example 1 and Comparative Examples 1 to 4 , the time until the relaxation elastic modulus G decreases to 1/10 after a temperature of 5 ° C. and 0.01 seconds after applying the strain is 0. It can be seen that by using the composition for anisotropic dye film of 1 second or less, an anisotropic dye film having high coating film uniformity and high dichroism can be formed.

  The anisotropic dye film of the present invention is useful for various polarizing elements such as a polarizing plate included in a light control element, a liquid crystal element (LCD), and an organic electroluminescence element (OLED) display element.

Claims (5)

A composition for an anisotropic dye film that includes a dye having a free acid form represented by the following formula and is capable of forming a lyotropic liquid crystal phase,
Containing 0.9 equivalents or more and 0.99 equivalents or less of a cation, and 0.02 equivalents or more and 0.1 equivalents or less of a strongly acidic anion, with respect to the acidic group of the dye,
A composition for anisotropic dye film, characterized in that the time until the relaxation elastic modulus G decreases to 1/10 at a temperature of 5 ° C. and 0.01 seconds after applying strain is 0.1 seconds or less.

(In the above formula, X ¹ represents a hydrogen atom or a sulfo group. A ¹ has a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a substituent. B ¹ represents an optionally substituted aromatic heterocyclic group, B ¹ represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and n represents Represents 1 or 2.)   The composition for an anisotropic dye film according to claim 1, which is used for forming an anisotropic dye film by a wet film forming method. The anisotropic dye film | membrane formed using the composition for anisotropic dye films | membranes of any one of Claim 1 or 2 . A dye whose free acid form is represented by the following formula, and an acidic group of the dye: cation 0.9 equivalent or more and 0.99 equivalent or less, strong acid anion 0.02 equivalent or more and 0.1 equivalent or less An anisotropic dye film comprising:

(In the above formula, X ¹ represents a hydrogen atom or a sulfo group. A ¹ has a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a substituent. B ¹ represents an optionally substituted aromatic heterocyclic group, B ¹ represents an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group, and n represents Represents 1 or 2.) Polarizing element using the anisotropic dye film according to claim 3 or 4.