KR102601009B1 - A composition containing a dichroic dye, a dye film manufactured using the same, and a polarizing element having the dye film - Google Patents

Abstract

The present invention relates to a composition containing a dichroic dye useful for forming a dye film capable of producing a polarizing element with excellent coatability, high quality, and excellent polarization performance, a dye film manufactured using the same, and a polarizing element having the dye film. The purpose is to provide.
(A) at least one type of dichroic dye, and (B) at least selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether. A composition comprising one type of surfactant and (C) a solvent, wherein the HLB value of the surfactant is 12.5 or more and 17.5 or less.

Description

A composition containing a dichroic dye, a dye film manufactured using the same, and a polarizing element having the dye film

The present invention relates to a composition containing a dichroic dye useful for forming a dye film capable of producing a polarizing element showing a high degree of polarization, and a dye film manufactured using the same. Additionally, the present invention relates to a polarizing element having the above dye film and excellent polarization performance.

Polarizing elements used in liquid crystal displays, sunglasses, goggles, etc. are generally made by adsorbing a dichroic dye such as iodine or a dichroic dye to a film made from a polymer material such as polyvinyl alcohol, and then uniaxially stretching the resulting film. It is manufactured by orienting the dichroic dye molecules in a certain direction, or by uniaxially stretching the polymer membrane and then adsorbing the dichroic dye. However, since the polarization axis and absorption axis of the polarizing element obtained by these methods are perpendicular to each other, the shape of the polarizing element is usually limited to a flat shape. In addition, in the production of such a polarizing element, a polyvinyl alcohol film is swollen and dyed, then this is stretched in an aqueous solution of boric acid, further washed with water and dried, and then a protective film is attached to the obtained film using an adhesive. It required a complicated process to do it. In addition, in order to more simply install a polarizing element at a desired portion and to manufacture various display elements including liquid crystal displays, a polarizing element with polarization in an arbitrary direction in a fine pattern shape or a curved surface shape is used. Polarizing elements are in demand.

In consideration of these problems with conventional polarizing elements, Non-Patent Document 1 discloses a method of producing a polarizing element by orienting dichroic dye molecules in a certain direction by rubbing treatment. However, the coatability of the dye solution on the substrate decreases due to scratches and dust on the substrate caused by the rubbing step in the rubbing treatment, and electrical scratches caused by static electricity. For this reason, there were uncoated areas on the obtained dye film, and as a result, the quality of polarization performance in the polarizing element having the dye film was not satisfactory.

Patent Document 1 discloses a technique for obtaining a polarizing element with higher polarization performance by using a photo-alignment film to orient dichroic dye molecules in contact with the photo-alignment film in an arbitrary direction. However, when the surface of the dye film of the polarizing element is observed with an atomic force microscope (AFM), there are parts where the dichroic dye is uniformly oriented and parts (craters) where most of the dichroic dye is not present and is not oriented. . Therefore, the polarization performance of the obtained polarizing element did not meet sufficient requirements as a practical level for polarizing elements for display elements.

In Patent Document 2, in order to further improve the uniformity of the orientation of the dichroic dye molecules and the polarization performance of the obtained polarizing element, the occurrence of craters is reduced as much as possible and the overall orientation of the dichroic dye compound is increased to provide practical use for display elements. A method of manufacturing a polarizing element at a similar level is disclosed. The polarizing element uses a liquid crystalline polymer thin film having a photoactive group as an alignment film, irradiates linearly polarized light on the thin film, aligns the molecular axis of the photoactive group in the polarized light irradiation portion in a certain direction, and then passes through a mask of a different micro-pattern shape to another layer. It is manufactured by irradiating linearly polarized light having a polarization axis and then applying a dichroic dye solution to the thin film using a roll coater so that a specific range of pressure is applied in the direction perpendicular to the substrate. However, the alignment film that serves as the substrate is special and very expensive, and in addition, in manufacturing the polarizing element, it is necessary to adjust the compression pressure so that a specific pressure is applied between the roll and the substrate. Therefore, it is desirable to develop a polarizing element that is not limited to a specific substrate and can be manufactured using various substrates.

Patent Document 1: Japanese Patent Application Publication No. 7-261024 Patent Document 2: Japanese Patent No. 4175455

Non-patent Document 1: 「Journal of the Electronic Information and Communication Society」, 1988, JJ71-C, p.1188

Since the dye film obtained by applying a composition containing a conventional dichroic dye and the polarizing element obtained from the dye film do not reach sufficiently satisfactory quality, it is necessary to further improve the quality. Additionally, there is a need to develop a polarizing element that can be easily manufactured without using a special substrate.

Therefore, an object of the present invention is a composition containing a dichroic dye useful for forming a dye film capable of producing a polarizing element with excellent coatability, high quality, and excellent polarization performance, a dye film manufactured using the same, and the corresponding The object is to provide a polarizing element having a dye film.

As a result of examining how to solve the above problems, the present inventor found that

(A) at least one dichroic dye, and (B) selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether. A dye that can produce a high-quality polarizing element with no polarization defects and excellent polarization performance by using a composition containing at least one type of surfactant and (C) a solvent, and the HLB value of the surfactant is 12.5 or more and 17.5 or less. It was discovered for the first time that a membrane could be obtained.

That is, the main structure of the present invention is as follows:

(1) A group consisting of (A) at least one dichroic dye and (B) polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether. A composition comprising at least one surfactant selected from the group consisting of and (C) a solvent, wherein the HLB value of the surfactant is 12.5 or more and 17.5 or less.

(2) The composition according to (1), wherein the dichroic dye is a water-soluble azo dye.

(3) The composition according to (1) or (2), wherein the dichroic dye is a compound represented by the following formula (1) or a salt thereof.

[Equation 1]

In Equation 1 above,

X ₁ shows a phenyl group or naphtil group having one or two sulfonal acids and an alkoxy period with a hydroxyl group or an alkoxy period of 1 to 3.

X _{2 and} It has 1 or 2 substituents selected from the group,

R ₁ is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, an acetyl group, a benzoyl group, or an unsubstituted phenyl group, an alkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, an amino group, a sulfo group, or a carbon number. represents a phenyl group substituted with an amino group having an alkyl group of 1 to 4,

m is 0 or 1, and

n is 1 or 2)

(4) The composition according to (3), wherein X ₁ is a compound represented by the following formula 3 as a substituent or a salt thereof.

[Equation 3]

(In Equation 3 above, j is 1 or 2.)

(5) The composition according to any one of (1) to (4), wherein the polyoxyethylene alkylene alkyl ether is polyoxyethylene polyoxypropylene alkyl ether or polyoxyethylene polyoxypropylene block polymer.

(6) The composition according to any one of (1) to (5), which contains a total of 0.1 to 15 parts by mass of the dichroic dye per 100 parts by mass of the solvent.

(7) The composition according to any one of (1) to (6), wherein the solvent contains at least water.

(8) A dye film produced using the composition according to any one of (1) to (7).

(9) A polarizing element having the dye film according to (8).

(10) The polarizing element according to (9), wherein the dichroic ratio is 5 or more.

The composition containing the dichroic dye in the present invention is excellent in coatability. Therefore, when producing a dye film using the composition of the present invention, for example, even if a rubbing treatment is performed on the substrate, a dye film in which defects in coating to the substrate that occurred in the prior art are improved can be formed. Additionally, by using the dye film, a high-quality polarizing element with no polarization defects and excellent polarization performance can be obtained. Furthermore, in the dye film of the present invention, since the material used as a base is not limited to a special material, the dye film and the polarizing element provided therewith can be manufactured more simply.

Below, the present invention is explained in detail. In the following, the numerical range indicated using “~” means a range including the numerical values written before and after “~” as the lower limit and upper limit. In addition, unless otherwise specified, the compounds (substituents) represented by Formulas 1 to 3 are expressed in the form of free acids, and salts of free acids mean salts of hydrophilic groups such as hydroxy groups and sulfonic acid groups. In addition, in the following description, unless otherwise specified, in order to avoid complexity, "the compound represented by formula 1 or a salt thereof", "the compound represented by formula 2 or a salt thereof", "the compound represented by formula 3 or a salt thereof" ” are respectively described as “the compound represented by Formula 1,” “the compound represented by Formula 2,” and “the compound represented by Formula 3.”

First, each component included in the composition of the present invention will be described. The composition of the present invention includes (A) at least one dichroic dye, and (B) polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether. It is a composition containing at least one type of surfactant selected from the group consisting of, and (C) a solvent, and the HLB value of the surfactant is 12.5 or more and 17.5 or less.

(A) Dichroic pigment

The composition of the present invention contains a dichroic dye as a main component for forming a dye film. A dichroic dye is a compound that exhibits polarization by being arranged in a certain direction by itself or in aggregate. Examples of such dichroic dyes include azo dyes, stilbene dyes, pyrazolone dyes, and triphenylmethane dyes. , pigment compounds such as quinoline-based pigments, oxadine-based pigments, thiazine-based pigments, and anthraquinone-based pigments. The dichroic dye used in the present invention is a compound that exhibits lyotropic liquid crystallinity under certain solvent composition, dye concentration, and temperature conditions, for example, "Application of Functional Colorants", 1st edition, supervised by Masahiro Irie. , CMC Co., Ltd., June 2002, p. The dichroic dye described in 102-104 can be mentioned. Additionally, it is preferable to use a water-soluble azo dye as the dichroic dye, and among these, a compound having an aromatic ring structure is more preferable. Examples of aromatic ring structures include heterocycles such as benzene, naphthaline, anthracene, and phenanthrene, as well as thiazole, pyridine, pyrimidine, pyridazine, pyrazine, and quinoline, or quaternary salts thereof, as well as benzene and naphthalene. Condensed rings with talin and the like can be mentioned. In particular, it is preferable to introduce a hydrophilic substituent such as a sulfonic acid group, carboxyl group, amino group, or hydroxyl group, or a salt of a sulfonic acid group or carboxyl group into these aromatic rings.

Specific examples of such dichroic pigments include, for example, C.I.Direct Orange 39, C.I.Direct Orange 41, C.I.Direct Orange 49, C.I.Direct Orange 72, C.I.Direct Red 2, C.I.Direct Red 28, C.I.Direct Red 39, C.I.Direct Red 79, C.I.Direct Red 81, C.I.Direct Red 83, C.I.Direct Red 89, C.I.Direct Violet 9, C.I.Direct Violet 35, C.I.Direct Violet 48, C.I.Direct Violet 57, C.I.Direct Blue 1, C.I.Direct Blue 15, C.I.Direct Blue 67, C.I.Direct Blue 78, C.I.Direct Blue 83, C.I.Direct Blue 90, C.I.Direct Blue 98, C.I.Direct Blue 151, C.I.Direct Blue 168, C.I.Direct Blue 202, C.I.Direct Green 42, C.I.Direct Green 51, C.I.Direct Green 59, C.I.Direct Green 85, C.I.Direct Yellow 4, C.I.Direct Yellow 12, C.I.Direct Yellow 26, C.I.Direct Yellow 44, C.I.Direct Yellow 50, Mordant Yellow 26, C.I.No.27865, C.I.No.27915, C.I.No. .27920, C.I.No.29058, C.I.No.29060, etc., and furthermore, Japanese Patent Application Publication No. 1-161202, Japanese Patent Application Publication No. 1-172906, Japanese Patent Application Publication No. 1-172907, and Japanese Patent Application Publication No. 1. Examples include dichroic dyes described in publications such as -183602, Japanese Patent Laid-Open No. 1-248105, Japanese Patent Laid-Open No. 1-265205, and Japanese Patent Laid-Open No. 9-230142.

Among the dichroic dyes shown in the specific examples above, the compounds represented by the following formula 1 or formula 3 are particularly preferable, and the compounds represented by the formula 1 are particularly preferable. The compounds represented by Formula 1 and Formula 3 exist as free acids or salts thereof. The salt of the free acid is not particularly limited, and may be any salt such as an alkali metal salt such as Li, Na, or K, or a quaternary ammonium salt. By using such a dichroic dye, the polarization performance of the obtained polarizing element can be improved.

[Equation 1]

(In equation 1,

X ₁ shows a phenyl group or naphtil group having one or two sulfonal acids and an alkoxy period with a hydroxyl group or an alkoxy period of 1 to 3.

X _{2 and} It has 1 or 2 substituents selected from the group,

R ₁ is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, an acetyl group, a benzoyl group, or an unsubstituted phenyl group, an alkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, an amino group, a sulfo group, or a carbon number. represents a phenyl group substituted with an amino group having an alkyl group of 1 to 4,

m is 0 or 1, and

n is 1 or 2.)

[Equation 2]

In Equation 2 above,

Y ₁ represents a naphthyl group that has one or two sulfonic acid groups and may also include a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms,

Y ₂ and Y ₃ each independently represent a phenylene group or a naphthylene group, and the phenylene group or naphthylene group is a group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, and a sulfonic acid group. It has 1 or 2 types of substituents selected from,

R ₂ is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, an acetyl group, a benzoyl group, or an unsubstituted phenyl group, an alkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, an amino group, a sulfo group, or a carbon number. represents a phenyl group substituted with an amino group having an alkyl group of 1 to 4,

As a phenylazo group

is substituted at any one of the 5th, 6th, 7th, or 8th positions of the terminal naphthyl group,

R ₃ and R ₄ each independently represent a hydrogen atom, a hydroxyl group, a sulfonic acid group, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, q is 0 or 1, while p is 1 or It is 2.)

Specific examples of the compound represented by formula 1 include the following:

.

In addition, specific examples of the compound represented by formula 2 include, for example:

.

Among the compounds represented by Formula ₁ or Formula ₂ , polarization performance can be further improved when In view of the ratio, it is preferable to use a compound represented by formula 1 having a compound represented by formula 3 below as a substituent. The corresponding substituents exist as free acids or salts thereof, as in the compounds represented by Formulas 1 and 2. The salt of the free acid is not particularly limited, and may be any salt such as an alkali metal salt such as Li, Na, or K, or a quaternary ammonium salt.

[Equation 3]

(In equation 3, j is 1 or 2.)

The dichroic dye of this invention may be used individually by 1 type, or may use 2 or more types together. The combined use of two or more types of dichroic dyes is not particularly limited, but the dichroic ratio of the dichroic dye can be further improved by using the added dichroic dye. In addition, the total content of all dichroic dyes contained in the composition of the present invention is not particularly limited, but in order to provide high anisotropy to the dye film, it is 0.1 to 15 parts by mass in total with respect to 100 parts by mass of the solvent (C) below. parts, preferably 0.3 to 10 parts by mass, more preferably 0.5 to 7 parts by weight.

(B) Surfactant

The composition of the present invention is selected from the group consisting of polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether as other components in the production of the dye film. , and also contains at least one type of surfactant having an HLB value of 12.5 or more and 17.5 or less. By using such a surfactant, coating defects that occur during application can be improved in the conventional production of a dye film on a substrate. In addition, in the method for manufacturing a polarizing element described in Patent Document 2, in order to reduce the shear stress parallel to the substrate during application, it is necessary to adjust the pressure so that a specific pressure is applied between the roll and the substrate in manufacturing the polarizing element. However, since the composition of the present invention contains a specific surfactant, such special steps become unnecessary when applying the composition of the present invention to a base material. In addition, even if the composition of the present invention is applied to a rubbed substrate, a substrate provided with a photo-alignment layer, a substrate damaged by friction, or a stretched substrate, the resulting dye film has a size that can be visually confirmed, for example, 50 Uncoated areas that may occur with a size of ㎛ or larger are reduced, and as a result, a dye film with improved coating defects can be produced.

The surfactant used in the present invention has an HLB value of 12.5 or more and 17.5 or less, and preferably, the HLB value is 13.0 or more and 17.0 or less. If the HLB value is less than 12.5, coating defects occurring in the dye film cannot be improved, and if the HLB value is greater than 17.5, the dichroic dye cannot be oriented in the dye film. Specific examples of polyoxyethylene alkyl ethers having the above-mentioned HLB value include Emargen 1108 (HLB value 13.4), manufactured by Kao Corporation, and Emargen 1118 S-70 (HLB value 16.4), manufactured by Kao Corporation.

As polyoxyethylene alkylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether or polyoxyethylene polyoxypropylene block polymer is particularly preferable. Specific examples of the polyoxyethylene alkylene alkyl ether having the above HLB value include, for example, polyoxyethylene polyoxypropylene alkyl ether, Emargen LS-106 (HLB value 12.5) manufactured by Kao Corporation, and Emargen LS-110 manufactured by Kao Corporation. (HLB value 13.4), Emargen LS-114 (HLB value 14.0) manufactured by Kao Corporation, and Emargen MS-110 (HLB value 12.7) manufactured by Kao Corporation. Examples of the polyoxyethylene polyoxypropylene block polymer include, For example, Newpole PE-68 (HLB value 15.7) manufactured by Sanyo Kasei, Newpole PE-78 (HLB value 15.6) manufactured by Sanyo Kasei, Newpole PE-108 (HLB value 15.5) manufactured by Sanyo Kasei, and Newpole PE manufactured by Sanyo Kasei. An example is -128 (HLB value 15.6). Among these, in particular, polyoxyethylene polyoxypropylene alkyl ethers include Emargen LS-106 manufactured by Kao Corporation, Emargen LS-110 manufactured by Kaos Corporation, Emargen LS-114 manufactured by Kaos Corporation, and Emargen MS-110 manufactured by Kaos Corporation. This is preferred, and as the polyoxyethylene polyoxypropylene block polymer, Newpol PE-68 manufactured by Sanyo Kasei is preferred.

In addition, specific examples of the polyoxyethylene distyrenated phenyl ether having the above HLB value include, for example, Emargen A-60 manufactured by Kao Corporation (HLB value 12.8) and Emargen A-90 manufactured by Kao Corporation (HLB value 14.5). Specific examples of polyoxyethylene tribenzylphenyl ether having the above HLB value include, for example, Emargen B-66 (HLB value 13.2) manufactured by Kao Corporation.

The surfactant of the present invention may be used individually, or two or more types may be used in combination. In addition, the total content of all surfactants contained in the composition of the present invention is 0.01 to 3 parts by mass, preferably 0.05 parts by mass, with respect to 100 parts by mass of the solvent (C) below, from the viewpoint of not inhibiting the orientation of the dichroic dye. to 2 parts by mass.

(C) Solvent

The composition of the present invention contains a solvent as a coating liquid. These solvents are not particularly limited as long as they can dissolve the dichroic dye used, and examples include water, alcohols, ethers, pyridine, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N -Pyrrolidinone (NMP), dimethylacetamide (DMAC), dimethylimidazoline (DMI), etc. may be included, and among these, only one type of solvent may be included, or a plurality of solvents may be included. In particular, when using a water-soluble dichroic dye, water or a mixed solvent with the above-mentioned organic solvent is preferable as the solvent if it mainly contains water. The mixing amount of the organic solvent with respect to water is arbitrary, but is preferably 0 to 50% by mass, especially 0 to 20% by mass, with respect to water.

Next, the dye film and polarizing element produced using the composition of the present invention, and their production method are explained. The dye film of the present invention is manufactured by applying the composition to a substrate and subsequently drying it. When the dye film of the present invention is formed on a base material and used as a polarizing element, a laminate composed of the base material and the dye film may be used as a polarizing element, and the laminate in which a protective layer, etc. is further laminated on the surface of the dye film can be used as a polarizing element. It can also be used as . As a base material used when forming the dye film of the present invention, for example, glass plates such as silica-based glass and hard glass, quartz plates, etc., polysiloxane resin, ABS resin, cycloolefin resin, acetal resin, and (meth)acrylic resin. , polyesters such as cellulose acetate, cellulose acetate, chlorinated polyether, ethylene-vinyl acetate copolymer, fluororesin, ionomer, methylpentene polymer, nylon, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, Polyimide, polyamide, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, polyarylate, polyethylene, polypropylene, polystyrene, polysulfone, cycloolefin resin, vinyl acetate resin, vinylidene chloride resin, AS resin, Plastic plates or sheets (films) made of various materials such as vinyl chloride resin, alkyd resin, aryl resin, amino resin, urea resin, melamine resin, epoxy resin, phenol resin, unsaturated polyester resin, silicone resin, polyurethane, and the above patents. Photoactive molecules (common name, photo-alignment film) described in Document 1 or Patent Document 2, or films or plates on which these resins are laminated or coated, or on the surface, silicon oxide, tin oxide, indium oxide, aluminum oxide, titanium oxide, and chromium oxide , a substrate coated with metal oxide such as zinc oxide, silicon nitride, silicon carbide, etc. Additionally, a substrate (film) whose surface is covered with a highly reflective metal thin film can also be used as a substrate. These substrates may be flat or curved. Additionally, the described thickness is 1 μm to 500 μm, and is preferably 10 to 100 μm.

By using such a substrate by rubbing, photo-aligning, or stretching, the dye film of the present invention having a polarizing function can be formed. Rubbing is a method of rubbing a base material with a specific cloth as described in Japanese Patent Application Laid-Open No. 8-152515 and Japanese Patent Application Laid-open No. 2002-90743, or as described in Japanese Patent Application No. 2012-015492 or Japanese Patent Application No. 2012-064912. As described above, a method of performing uniaxial polishing processing using an abrasive or a material containing an abrasive is available. Photo-alignment refers to, for example, as described in Patent Document 1 or Patent Document 2, polarized light is irradiated on a polymer or aggregate having a photoactive group (a material generally called a photo-alignment film), and the photoactive molecules are aligned. By polymerizing or decomposing, the molecule is made to exhibit anisotropy along a specific axis. Stretching refers to orienting molecules to a specific axis by stretching a polymer or substrate obtained from a resin by heating or the like. Therefore, the dichroic dye applied on the substrate can be aligned by rubbing, photo-aligning, or stretching the substrate.

By subjecting the substrate to corona discharge treatment or ultraviolet irradiation, the dichroic ratio of the polarizing element described later is improved, and it is possible to improve the polarization characteristics of the obtained polarizing element. Corona discharge treatment can be applied by using various commercially available corona discharge processors as an apparatus for performing corona discharge treatment, and the use of a corona treatment machine with an aluminum head is particularly preferable. The conditions for corona discharge treatment are about 20 to 400 W·min·m ^-2 as energy density, preferably about 50 to 300 W·min·m ^-2 during one corona discharge treatment. Additionally, if one corona discharge treatment is insufficient, the corona discharge treatment may be performed two or more times. Ultraviolet irradiation can similarly be applied by using various commercially available ultraviolet irradiation devices. There is no particular limitation on the wavelength of ultraviolet rays used, but for example, deep ultraviolet rays of 300 nm or less are preferable. In addition, ultraviolet irradiation is preferably performed under an oxygen stream, and the irradiation time of ultraviolet rays is sufficient to be as long as a few minutes.

The composition of the present invention containing a dichroic dye (solution containing the dichroic dye) is added dropwise to the surface of the substrate as described above, and the dichroic dye having a uniform thickness is applied to the substrate by a coater or a rotary coating method. Install the coating film. The method of providing a coating film of a dichroic dye is not particularly limited as long as a solution containing the dichroic dye can be applied, but for example, a method of immersing the substrate in a solution containing the dichroic dye, dichroic dye A method of applying a dye solution using a bar coater, a method of applying a dye solution using an inkjet printer applicator such as the piezo method, thermal method, or bubble jet (registered trademark) method used for home or commercial purposes, or a rotational application using a spin coater. Methods include roll coater application, flexo printing, screen printing, gravure printing, curtain coater application, spray coater application, etc. In particular, roll coater application, curtain coater application, and spray application with a spray coater are preferred. .

The dye film of the present invention can be obtained by continuously drying the substrate to which the solution of the dichroic dye has been applied and forming a layer of the dichroic dye in a solid state. Drying conditions vary depending on the type of solvent, the type of dichroic dye, the amount of solution containing the applied dichroic dye, the concentration of the dichroic dye, etc., but the drying temperature is room temperature to 100°C, preferably room temperature to 50°C. , Humidity is preferably around 20 to 95%RH, preferably around 30 to 90%RH.

From the viewpoint of improving polarization characteristics, the thickness of the dye film of the present invention is preferably thin, for example, 0.001 to 10 μm, and particularly preferably 0.05 to 2 μm. In addition, in order to form the dye film of the present invention within this thickness range, the thickness of the coating film coated with the solution containing the dichroic dye is preferably 2 to 10 μm, and more preferably 3 to 5 μm.

Additionally, the substrate to which the solution containing the dichroic dye has been applied can be further subjected to heat treatment and/or humidification treatment. By performing heat treatment and/or humidification treatment, the adhesion of the dichroic dye to the substrate, the polarization performance, dichroic ratio, and durability of the obtained polarizer can be improved. The temperature of the heat treatment is room temperature to 110°C, preferably 60 to 90°C, and the humidity of the humidification treatment is preferably 40 to 95%RH, preferably 50 to 90%RH.

The dye film of the present invention obtained in this way can be used as a polarizing element. The polarizing element of the present invention has a dichroic ratio (Rd), and the dichroic ratio is generally defined as the ratio of the absorbance along the absorption axis to the absorbance along the transmission axis. The dichroic ratio of the polarizing element of the present invention is calculated by the following equation 4, and a dichroic ratio of 5 or more means that it exhibits a polarizing function. The dichroic ratio of the polarizing element of the present invention is 5 or more, preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more. When the dichroic ratio is less than 5, the degree of polarization is less than 65%, and the function as a polarizing element is not sufficient. The degree of polarization of the polarizing element is usually 65% or more, preferably 70% or more, and more preferably 80% or more. Polarization degree is the ratio of the light intensity of the polarized component to the electric light intensity, and the higher the polarization degree, the higher the polarization performance. In Equation 4 below, Ky is the transmittance of the axis that transmits the most light when polarized light is incident, and Kz is the transmittance of the axis that absorbs the most light when polarized light is incident.

[Equation 4]

Rd = Log (Kz /100)/ Log (Ky/100)

As a method of further improving the dichroic ratio of the polarizing element of the present invention, a molecular anisotropy greater than the molecular anisotropy given to the surface of the stretched film is applied to the surface of the stretched film as a substrate in the same direction as the stretching axis of the film. By expressing , the dichroic ratio can be further improved. As a method of expressing molecular anisotropy greater than that of the stretched film, for example, a method of rubbing the stretched film is included. Such rubbing is exemplified in, for example, Japanese Patent Application Laid-Open No. 06-110059 and Japanese Patent Application Laid-Open No. 2002-90743. The measurement of the molecular anisotropy of the stretched film surface is not particularly limited, but is measured, for example, according to a measurement method used for measuring the anchoring of an alignment film for liquid crystals. In addition, the device for measuring such molecular anisotropy is not particularly limited, but for example, Lay Scan manufactured by MARITEX SCOTT, etc. can be used.

It is also possible to produce a polarizing element that exhibits molecular anisotropy in the long axis direction on the surface of a film whose phase difference axis (slow axis or fast axis) is at a different angle from the long axis direction of the film. Specifically, the polarization axis or absorption axis of the polarizing element can be arbitrarily controlled by imparting molecular anisotropy by rubbing or the like to the surface of a stretched film having a retardation axis at an arbitrary angle with respect to the long axis direction of the film. That is, by using a stretched film that has a phase axle at an angle different from the long axis direction of the film and exhibits molecular anisotropy on the surface in the long axis direction, the phase axle in the stretched film as a base material and the phase axle It becomes possible to manufacture a polarizing element having an absorption axis or polarization axis at different angles. The angle formed between the retardation axis of the stretched film serving as the substrate and the absorption axis or polarization axis of the polarizing element is most preferably any of 15°, 45°, 75°, and 90°. The reason why such an angle is desirable is that, generally, when you want to control linearly polarized light to circularly polarized light, a film with a phase difference of 1/4 with respect to the length of the wavelength you want to control is placed at 45° with respect to the absorption axis of the polarizing element. It is known to be installed. Additionally, as a method of reversing the polarization axis of linearly polarized light, it is known to install a film with a phase difference of 1/2 at 90° with respect to the length of the wavelength to be controlled. The reason for installing the film at 15° or 75° with respect to the absorption axis or polarization axis of the polarizing element is that this angle is a prescription that shows a 1/4 phase difference over a wide range of wavelengths (commonly called a broadband achromatic retardation film) This is because it is the axis angle used in ). This makes it possible to arbitrarily control the polarization axis or absorption axis of the polarizing element.

The dye film of the present invention manufactured as described above is in a solid state such as amorphous or crystalline, but since the dye film is usually inferior in mechanical strength, the surface of the dye film is subjected to rake treatment, crosslinking treatment with a silane coupling agent, or protection. layer is installed. Lake treatment refers to electrically bonding a metal ion or the like to a water-soluble dichroic dye. Rakeizing a dichroic pigment is also called laking or insolubilization. Suitable compounds for lakes include aluminum chloride, iron chloride, calcium chloride, barium chloride, nickel chloride, magnesium chloride, copper chloride, barium acetate, and nickel acetate. There is no particular limitation as long as the dichroic dye is insoluble in water. In addition, the crosslinking treatment using the silane coupling agent is not particularly limited. For example, the dye film may be fixed by performing crosslinking treatment by heating, etc. using the silane coupling agent described in Japanese Patent Application Laid-Open No. 2011-53234. You can. Additionally, the protective layer is usually provided by a coating method such as coating the dye film with an ultraviolet curable or heat-strengthening transparent polymer film, or laminating the dye film with a transparent polymer film such as a polyester film or cellulose acetate film. The protective layer can be provided as a polymer coating layer or as a laminate layer of a film. As the transparent polymer or film forming the transparent protective layer, a transparent polymer or film with high mechanical strength and good thermal stability is preferable. Materials used as a transparent protective layer include, for example, cellulose acetate resin such as triacetylcellulose or diacetylcellulose or its film, acrylic resin or its film, polyvinyl chloride resin or its film, nylon resin or its film, polyester. Resin or its film, polyarylate resin or its film, cyclic polyolefin resin or its film containing a cyclic olefin such as norbornene as a monomer, polyethylene, polypropylene, polyolefin having a cyclo or norbornene skeleton or its Examples include copolymers, resins or polymers whose main or side chains are imide and/or amide, or films thereof. Additionally, as a transparent protective layer, a resin having liquid crystallinity or a film thereof may be provided. The thickness of the protective layer is, for example, about 0.5 to 200 μm. One or more layers of resin or film serving as a protective layer can be provided on one or both sides of the polarizing element, and when multiple protective layers are used, these protective layers may be the same or different.

The polarizing element of the present invention can be used for polarized sunglasses, goggles, etc. During the manufacturing process, the polarizing element of the present invention can be given a gray scale or a pattern having multiple polarization axes. A gradation display polarizing element or polarizing plate with gradation can be manufactured by using linearly polarized light through a mask pattern with light and dark or a photographic negative film when printing a polarizing pattern on a photoactive molecular layer. Additionally, a multi-axis polarizing element or polarizing plate having multiple polarization axes can be manufactured by irradiating linearly polarized light with different polarization axes to different parts when printing a polarization pattern on a photoactive molecular layer. Compared to the case of using a normal polyvinyl alcohol-based film, these additional functions can be provided simply by applying a solution containing a dichroic dye, so the desired polarizing plate can be obtained without dimensional change or shrinkage. . The lack of dimensional change is particularly effective for displays that require a polarizing element to be installed on one side, such as flexible displays and organic electroluminescent displays (commonly known as OLED). Furthermore, unlike conventional polarizing plates, difficult conditions are not required for applying the dye, and the production of the polarizing element is also very simple and easy in that the desired polarizing element can be easily obtained just by applying it.

[Example]

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In addition, evaluation of the transmittance shown in the examples was performed as follows.

The transmittance of each wavelength was measured using a spectrophotometer (“U-4100” manufactured by Hitachi Ltd.). The transmittance at each wavelength when measured with one dye film is set to the transmittance Ts, and the transmittance when two dye films are overlapped so that their absorption axes are the same is set to the parallel transmittance Tp, and the two dye films are used for their absorption. The transmittance when the axes overlap so as to be orthogonal was taken as the orthogonal transmittance Tc.

The degree of polarization ρ was determined by Equation 5 from the parallel transmittance Tp and the orthogonal transmittance Tc.

[Equation 5]

The dichroic ratio (Rd) was measured using V-7100 manufactured by Nippon Spectrophotography, and the obtained value was used as the measurement result.

Example 1

As a substrate, a rubbing cloth (MK0012, Taenakapile Textile Co., Ltd.) was wound on the non-reverse adhesive surface of a 100㎛ thick polyethylene terephthalate film (A-4100, manufactured by Dongyang Spinning, hereinafter abbreviated as “PET film”) at a speed of 100 rpm. Rubbing treatment was performed with a furnace load of 5 kgf. On the PET film surface subjected to the rubbing treatment, 5 parts by mass of C.I.Direct Blue 67 as a dichroic dye and 0.1 parts by mass of polyoxyethylene polyoxypropylene alkyl ether (Emargen LS-106 manufactured by Kao Co., Ltd.: HLB value 12.5) as a surfactant. A composition containing 100 parts by mass of water as a solvent was applied using a coater equipped with a glass rod set so that the gap with the PET film was 3 μm. The obtained coating film was left in an environment of 25°C and 70% humidity for 1 minute, and the solvent was dried. Additionally, the dried coating film was subjected to heat treatment and humidification treatment for 5 minutes in an environment of 60°C and 90% humidity to obtain the dye film of the present invention formed only from dye molecules. On the obtained dye film, an acrylic resin-based ultraviolet curable resin composition (SPC-920C, manufactured by Nippon Chemical Co., Ltd.) was applied with a spin coater so that the thickness of the protective layer after curing was 3 μm, and the resin composition was subsequently irradiated with ultraviolet rays. It was cured, and a protective layer was provided on the dye film. The polarizing element obtained in this way was used as a measurement sample.

Example 2

Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene polyoxypropylene alkyl ether (Emargen MS-110 manufactured by Kao Corporation) with an HLB value of 12.7, and its content was changed to 0.05 parts by mass. Except for this, measurement samples were prepared in the same manner as in Example 1.

Example 3

In the composition used in Example 1, the content of C.I.Direct Blue 67 as a dichroic dye was changed to 3 parts by mass, and Emargen LS-106 as a surfactant was changed to polyoxyethylene polyoxypropylene alkyl ether with an HLB value of 12.7. A measurement sample was prepared in the same manner as in Example 1, except that it was replaced with (Emargen MS-110 manufactured by Kao Corporation).

Example 4

The same procedure as in Example 1 except that Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene polyoxypropylene alkyl ether (Emargen MS-110 manufactured by Kao Corporation) with an HLB value of 12.7. Measurement samples were prepared.

Example 5

In the dye composition used in Example 1, two types of dichroic dyes were used in combination: 5 parts by mass of C.I.Direct Blue 67 and 1 part by mass of C.I.Direct Orange 72 as a dichroic dye, and Emargen as a surfactant. A measurement sample was prepared in the same manner as in Example 1, except that LS-106 was replaced with polyoxyethylene polyoxypropylene alkyl ether (Emargen MS-110, manufactured by Kao Corporation) with an HLB value of 12.7.

Example 6

Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene polyoxypropylene alkyl ether (Emargen MS-110 manufactured by Kao Corporation) with an HLB value of 12.7, and its content was changed to 1.0 parts by mass. Except for this, measurement samples were prepared in the same manner as in Example 1.

Example 7

The PET film as the substrate used in Example 1 was replaced with an 80 μm thick triacetylcellulose film (TD-80U manufactured by Fujifilm Corporation), and in the composition used in Example 1, C.I.Direct Blue 67 as a dichroic dye was added. Examples except that the content was changed to 10 parts by mass and Emargen LS-106 as the surfactant was replaced with polyoxyethylene polyoxypropylene alkyl ether (Emargen MS-110 manufactured by Kao Corporation) with an HLB value of 12.7. A measurement sample was prepared in the same manner as in 1.

Example 8

Same as Example 1 except that Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene polyoxypropylene glycol block polymer (Newpol PE-68 manufactured by Sanyo Chemical Industry Co., Ltd.) with an HLB value of 15.7. Measurement samples were prepared properly.

Example 9

A sample was measured in the same manner as in Example 1, except that Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene alkyl ether (Emargen 1118 S-70, manufactured by Kao Corporation) with an HLB value of 16.4. was manufactured.

Example 10

In the composition used in Example 1, two types of dichroic dyes were used in combination: 4 parts by mass of C.I.Direct Blue 67 and 4 parts by mass of C.I.Direct Orange 72 as a dichroic dye, and Emargen LS-106 as a surfactant. In the same manner as in Example 1, except that the HLB value was changed to polyoxyethylene alkyl ether polyoxyethylene distyrenated phenyl ether (Emargen A-90 manufactured by Kao Corporation) with an HLB value of 14.5, and the content was changed to 0.2 parts by mass. Measurement samples were prepared.

Example 11

Example except that Emargen A-90 as the surfactant used in Example 10 was replaced with polyoxyethylene alkyl ether polyoxyethylene distyrenated phenyl ether (Emargen A-60 manufactured by Kao Corporation) with an HLB value of 12.8. Measurement samples were prepared in the same manner as in 10.

Example 12

Emargen A-90 as the surfactant used in Example 10 was replaced with polyoxyethylene tribenzylphenyl ether (Emargen B-66, manufactured by Kao Corporation) with an HLB value of 12.8, and its content was changed to 0.1 part by mass. A measurement sample was prepared in the same manner as in Example 10.

Example 13

4-Methacryloyloxyazobenzene was dissolved in benzene to make a 20% by mass solution, and the azobenzene was polymerized at 60°C for 12 hours under degassing using azobisisobutyronitrile as an initiator. The obtained solution consisting of 10 parts by mass of the azobenzene-containing polymer and 90 parts by mass of toluene was spin-coated onto the PET film used in Example 1 so that the film thickness after drying was 0.1 μm, and then this PET film base material was coated with 100 parts by mass. Heat and dry at ℃ for 1 minute. Prepare an ultra-high pressure mercury lamp of 500 W/h, set the irradiated light to visible light (>400 nm) using a cutoff filter, and linearly polarize it through a polarizer. This linearly polarized light was irradiated at room temperature onto the coated surface of the substrate placed parallel to the polarization axis of the polarizing plate for 1 minute from a distance of 50 cm from the coated surface. On the surface of the substrate on which such photo-alignment treatment was performed, 5 parts by mass of C.I.Direct Blue 67 and 0.1 parts by mass of polyoxyethylene polyoxypropylene alkyl ether (Kao Emargen MS-110: HLB value 12.7) as a dichroic dye were added. A composition containing 100 parts by mass of water was applied using a coater equipped with a glass rod set so that the distance from the substrate was 3 μm. The obtained coating film was left in an environment of 25°C and 70% humidity for 1 minute, and the solvent was dried. Additionally, the dried coating film was subjected to heat treatment and humidification treatment for 5 minutes in an environment of 60°C and 90% humidity to obtain the dye film of the present invention. On the obtained dye film, a protective layer similar to Example 1 was provided. The polarizing element obtained in this way was used as a measurement sample.

Comparative Example 1

Emargen LS-106 as the surfactant used in Example 1 was replaced with the nonionic surfactant used in Example 1 of Patent Document 1, that is, polyoxyethylene lauryl ether (Emargen manufactured by Kao Corporation) with an HLB value of 12.1. A measurement sample was prepared in the same manner as in Example 1, except that it was changed to 108), and was used as a comparative example sample.

Comparative Example 2

In the composition used in Example 1, the content of C.I.Direct Blue 67 as a dichroic dye was changed to 10 parts by mass, and Emargen LS-106 as a surfactant was changed to the nonionic surfactant of Comparative Example 1 (manufactured by Kao Corporation) Emargen 108), and its content was changed to 1 part by mass, a dichroic dye aqueous solution similar to Example 1 of Patent Document 1 was prepared, and a measurement sample was prepared in the same manner as Example 1, and was used as a comparative example sample. did.

Comparative Example 3

Emargen LS-106 as the surfactant used in Example 1 was replaced with an anionic surfactant used in Production 1 of the associative dichroic dye film of Patent Document 2, that is, sodium polyoxyethylene lauryl ether sulfate (Kao) with an HLB value of 25. A measurement sample was prepared in the same manner as in Example 1, except that it was replaced with Emar 20C), which was used as a comparative example sample.

Comparative Example 4

A measurement sample was prepared in the same manner as in Example 1, except that Emargen LS-106 as the surfactant used in Example 1 was not used, and was used as a comparative example sample.

Comparative Example 5

Instead of using Emargen LS-106 as the surfactant used in Example 1, the content of C.I.Direct Blue 67 as the dichroic dye was changed to 2 parts by mass, and the glass was set so that the gap with the PET film was 7 μm. A dye film and a measurement sample were produced in the same manner as in Example 1, except that the coating liquid containing the dichroic dye was applied using a coating machine equipped with a rod, and was used as a comparative example sample.

Comparative Example 6

Measurement was carried out in the same manner as in Example 1, except that Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene distyrenated phenyl ether (Emargen A-500, manufactured by Kao Corporation) with an HLB value of 18.0. A sample was prepared and used as a comparative example sample.

Comparative Example 7

A sample was measured in the same manner as in Example 1, except that Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene alkyl ether (Emargen 1150 S-60, manufactured by Kao Corporation) with an HLB value of 18.5. was prepared and used as a comparative example sample.

Comparative Example 8

A sample was measured in the same manner as in Example 1, except that Emargen LS-106 as the surfactant used in Example 1 was replaced with polyoxyethylene alkyl ether (Emargen 1150 S-70, manufactured by Kao Corporation) with an HLB value of 17.9. was prepared and used as a comparative example sample.

Table 1 shows Ts, Tp, Tc, ρ, and Rd at the wavelength with the highest degree of polarization obtained by measuring the samples obtained in Examples 1 to 13 and Comparative Examples 1 to 8. Additionally, the coatability of the obtained dye film was evaluated. Regarding coatability, if more than 10 uncoated areas of 50 ㎛ or larger in size can be visually confirmed on a 10 cm square dye film, it is considered that there is a coating defect in the dye film, and in Table 1, “×” indicates coating. “○” indicates that defects occur, and “○” indicates that no coating defects occur.

As revealed from the results in Table 1, the dye film produced using the composition of the present invention does not cause coating defects even if the base material is subjected to a rubbing treatment as in Examples 1 to 12, and the composition of the present invention has coating properties. It can be seen that a dye film that is excellent and has improved coating defects can be obtained. In addition, as in Example 13, it can be seen that even if the substrate is subjected to photo-alignment treatment, a composition with excellent coating properties and a dye film with improved coating defects can be obtained, as in Examples 1 to 12. In addition, as shown in Examples 1 to 13, the polarizing element having the dye film of the present invention exhibits not only a high transmittance (Ts), but also a high polarization degree (ρ) and a high dichroic ratio (Rd), In the present invention, it can be seen that as the coating defect of the dye film is improved, the polarization defect of the polarizing element is also improved.

On the other hand, the samples of Comparative Examples 1 and 2 using polyoxyethylene alkylene alkyl ether whose HLB value is outside the specifications of the present invention as a surfactant, and the HLB value of which is outside the specifications of the present invention and the surface that is not a surfactant specified in the present invention Coating defects occurred in the dye film in the sample of Comparative Example 3 using an activator and the sample of Comparative Example 4 without using a surfactant, respectively. From this, it can be seen that the coating defect of the dye film of these samples is not improved, and polarization defects also occur in the polarizing element having the dye film.

In addition, in the sample of Comparative Example 5, which, like Comparative Example 4, used a composition containing no surfactant and had a relatively thick dye film, the contrast of the polarizing element calculated from the parallel transmittance (Tp) and the orthogonal transmittance (Tc) was about 2, and the sample of Comparative Example 6 using a composition containing polyoxyethylene distyrenated phenyl ether whose HLB value is outside the specifications of the present invention, Comparative Example 7 using a composition containing polyoxyethylene alkyl ether whose HLB value is outside the specifications of the present invention, and For sample 8, the corresponding contrast was approximately 1. From this, it can be seen that even if such a polarizing element is applied to a display, it becomes a polarizing plate that hardly provides contrast to the display. In addition, the samples of Comparative Examples 5 to 8 had a polarization degree (ρ) of less than 65% and a dichroic ratio (Rd) of less than 5, so it can be seen that the function as a polarizing element is not sufficient.

From the above results, the dye film manufactured using the composition of the present invention improves coating defects during coating of the dye film obtained by applying a composition containing a conventional dichroic dye, and as a result, is of high quality without polarization defects and has excellent polarization performance. It can be seen that this excellent polarizing element was obtained.

The polarizing element of the present invention is not a polarizing element using a polyvinyl alcohol resin film like the conventional polarizing element, but can be manufactured by applying a solution containing a dichroic dye to a rubbed substrate, using the conventional process. Processes such as swelling, dyeing, and stretching required are unnecessary. In addition, since a polarizing element film can be manufactured using only a dichroic dye as a component exhibiting a polarizing function, it is possible to form an ultra-thin polarizing element. In addition, since a polarizing element can be manufactured by applying a solution containing a dichroic dye, it is not limited to the shape of a flat polarizing element such as a conventional polarizing plate, and it is also possible to form a curved or spherical polarizing element. possible. In particular, the conventional stretched film could only form a polarizing plate that passes polarized light perpendicular to the stretching direction, but since the polarizing element of the present invention can arbitrarily set the orientation direction with respect to the rubbed substrate, it can form a fine pattern shape. Alternatively, it is possible to form a polarizing element with polarization in any direction.

Claims (10)

(A) at least one dichroic dye, and (B) polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzylphenyl ether. It contains at least one surfactant selected from the group, and (C) a solvent,
The surfactant has an HLB value of 12.5 or more and 17.5 or less.
A composition, characterized in that the dichroic dye is a water-soluble azo dye having an aromatic ring structure.
The composition according to claim 1, wherein the dichroic dye is a compound represented by the following formula 1 or a salt thereof.
[Equation 1]

In Equation 1 above,
X ₁ shows a phenyl group or naphtil group having one or two sulfonal acids and an alkoxy group having a hydroxyl group or a carbon number of 1 to 3.
X _{2 and} It has 1 or 2 substituents selected from the group,
R ₁ is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, an acetyl group, a benzoyl group, or an unsubstituted phenyl group, an alkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, an amino group, a sulfo group, or a carbon number. represents a phenyl group substituted with an amino group having an alkyl group of 1 to 4,
m is 0 or 1, and
n is 1 or 2.
The composition according to claim 2, wherein X ₁ is a compound represented by the following formula 3 as a substituent or a salt thereof.
[Equation 3]

In equation 3 above, j is 1 or 2.
The composition according to claim 1, which contains a total of 0.1 to 15 parts by mass of the dichroic dye relative to 100 parts by mass of the solvent.
The composition according to claim 1, wherein the solvent includes at least water.
A pigment film manufactured using the composition according to claim 1.
A polarizing element comprising the dye film according to claim 6.
The polarizing element according to claim 7, wherein the dichroic ratio is 5 or more.
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