JP6661618B2 - Composition containing dichroic dye, dye film produced using the same, and polarizing element having the dye film - Google Patents

Description

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

  Polarizing elements used in liquid crystal display devices, sunglasses, goggles, etc. are generally prepared by adsorbing a dichroic dye such as iodine or a dichroic dye on a film made of a polymer material such as polyvinyl alcohol. Then, the obtained film is uniaxially stretched, and the dichroic dye molecules are oriented in a certain direction, or the polymer film is uniaxially stretched and then the dichroic dye is adsorbed. However, since the polarization axis and the 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 plate. Further, in the production of such a polarizing element, a polyvinyl alcohol film is swelled and dyed, and subsequently stretched in an aqueous boric acid solution, and further subjected to a water washing treatment and a drying treatment. A complicated process such as bonding a protective film using an adhesive was required. In addition, in order to more easily provide a polarizing element at a desired portion and further manufacture various display elements including a liquid crystal display, a polarizing element having a polarizing property in any direction in a fine pattern. There has been a demand for a polarizing element having a curved surface.

  In view of such a problem of the conventional polarizing element, Non-Patent Document 1 discloses a method of manufacturing a polarizing element by aligning dichroic dye molecules in a certain direction by a rubbing treatment. However, scratches and dust on the substrate caused by a rubbing step in the rubbing process, and electric scratches caused by static electricity, etc., lower the coatability of the dye solution on the substrate. Therefore, there was an uncoated portion on the obtained dye film, and as a result, the polarization performance of the polarizing element having the dye film was not satisfactory.

  Patent Document 1 discloses a technique for obtaining a polarizing element having 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), a portion where the dichroic dye is uniformly oriented and a portion where the dichroic dye is hardly present and are not oriented (Crater) exists. Therefore, the polarizing performance of the obtained polarizing element has not been sufficiently satisfied as a practical level in a polarizing element for a display element.

  Patent Document 2 discloses that in order to further improve the uniformity of the orientation of dichroic dye molecules and the polarization performance of the obtained polarizing element, the occurrence of craters is reduced as much as possible, and the orientation of the dichroic dye compound is increased as a whole. A method for manufacturing a polarizing element at a practical level for a display element is disclosed. The polarizing element is a liquid crystal polymer thin film having a photoactive group as an alignment film, irradiating the thin film with linearly polarized light, aligning the molecular axis of the photoactive group in the polarized light irradiation part in a certain direction, and then forming another micropattern. After irradiating linearly polarized light having different polarization axes through a mask, a dichroic dye solution is applied on the thin film with a roll coater so that a specific range of pressure is applied in a direction perpendicular to the substrate. Manufactured. However, an alignment film serving as a base material is special and very expensive, and further, in manufacturing a polarizing element, it is necessary to adjust a pressing pressure so that a specific pressure is applied between a roll and a substrate. Therefore, it is desired to develop a polarizing element that can be manufactured using various base materials without being limited to a specific base material.

JP-A-7-261024 Japanese Patent No. 4175455

"Transactions of the Institute of Electronics, Information and Communication Engineers", 1988, JJ71-C, p.1188

  A dye film obtained by applying a composition containing a conventional dichroic dye, and a polarizing element obtained from the dye film are not yet sufficiently satisfactory in quality, and thus further improve the quality. There is a need. There is also a demand for a polarizing element that can be easily manufactured without using a special substrate.

  Accordingly, an object of the present invention is to provide a composition containing a dichroic dye useful for forming a dye film which can produce a polarizing element having excellent coatability and high quality and excellent polarization performance, and a preparation using the same. And a polarizing element having the dye film.

The present inventor has conducted intensive studies in order to solve the above problems,
(A) at least one dichroic dye and (B) selected from the group consisting of polyoxyethylene alkyl ethers, polyoxyethylene alkylene alkyl ethers, polyoxyethylene distyrenated phenyl ethers and polyoxyethylene tribenzyl phenyl ethers By using a composition containing at least one surfactant to be used and a solvent (C) and having an HLB value of 12.5 or more and 17.5 or less, there is no poor polarization. It has been newly found that a dye film capable of producing a polarizing element having high quality and excellent polarization performance can be obtained.

（式（１）中、
Ｘ_１は、１つ若しくは２つのスルホン酸基と、水酸基若しくは炭素数が１乃至３のアルコキシ基を有するフェニル基又はナフチル基を表し、
Ｘ_２及びＸ_３は、それぞれ独立して、フェニレン基又はナフチレン基を表し、当該フェニレン基又はナフチレン基は、炭素数が１乃至３のアルキル基、炭素数が１乃至３のアルコキシ基、水酸基及びスルホン酸基からなる群から選択される１種又は２種の置換基を１つ又は２つ有しており、
Ｒ_１は、水素原子、炭素数が１乃至３のアルキル基、アセチル基、ベンゾイル基、或いは、非置換のフェニル基又は炭素数が１乃至４のアルキル基、炭素数が１乃至４のアルコキシ基、アミノ基、スルホ基若しくは炭素数が１乃至４のアルキル基を有するアミノ基で置換されたフェニル基を表し、
ｍは、０又は１であり、かつ
ｎは、１又は２である）
（４）Ｘ_１が、置換基として下記式（３）で表される化合物又はその塩であることを特徴とする（３）に記載の組成物。

（式（３）中、ｊは１又は２である。）
（５）前記ポリオキシエチレンアルキレンアルキルエーテルが、ポリオキシエチレンポリオキシプロピレンアルキルエーテル又はポリオキシエチレンポリオキシプロピレンブロックポリマーであることを特徴とする（１）乃至（４）のいずれか１つに記載の組成物。
（６）溶媒１００質量部に対して、前記二色性色素を合計０．１〜１５質量部含有することを特徴とする（１）乃至（５）のいずれか１つに記載の組成物。
（７）溶媒が少なくとも水を含むことを特徴とする（１）乃至（６）のいずれか１つに記載の組成物。
（８）（１）乃至（７）のいずれか１つに記載の組成物を用いて作製された色素膜。
（９）（８）に記載の色素膜を有する偏光素子。
（１０）二色比が、５以上であることを特徴とする（９）に記載の偏光素子。That is, the gist configuration of the present invention is as follows.
(1) Consisting of (A) at least one dichroic dye and (B) polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether and polyoxyethylene tribenzyl phenyl ether. A composition comprising at least one surfactant selected from the group 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.

(In equation (1),
X ₁ represents one or two sulfonic acid groups and a phenyl group or a naphthyl group having a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms,
X ₂ and X ₃ each independently represent a phenylene group or a naphthylene group, and the phenylene group or the naphthylene group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, It has one or two kinds of one or two kinds of substituents selected from the group consisting of sulfonic acid groups,
R ₁ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A phenyl group substituted by an amino group having an amino group, a sulfo group or an alkyl group having 1 to 4 carbon atoms,
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.

(In the formula (3), j is 1 or 2.)
(5) The polyoxyethylene alkylene alkyl ether is a polyoxyethylene polyoxypropylene alkyl ether or a polyoxyethylene polyoxypropylene block polymer, any one of (1) to (4). Composition.
(6) The composition according to any one of (1) to (5), wherein the dichroic dye is contained in a total amount of 0.1 to 15 parts by mass with respect to 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 a dichroic dye in the present invention has excellent coatability. Therefore, when producing a dye film using the composition of the present invention, for example, even if the substrate has been subjected to a rubbing treatment, forming a dye film in which the coating failure to the substrate that has occurred conventionally has been improved can do. In addition, by using the dye film, a polarizing element having high quality and excellent polarization performance without poor polarization can be obtained. Further, in the dye film of the present invention, since the material serving as the base material is not limited to a special material, a dye film and a polarizing element including the dye film can be manufactured more easily.

  Hereinafter, the present invention will be described in detail. Hereinafter, the numerical range represented by using “to” means a range including the numerical values described before and after “to” as the lower limit and the upper limit. Unless otherwise specified, the compounds (substituents) represented by the formulas (1) to (3) are represented in the form of a free acid, and the salt of the free acid is defined as a hydrophilic group such as a hydroxyl group or a sulfonic acid group. It means a salt of a sex group. In the following description, unless otherwise specified, in order to avoid complication, “a compound represented by the formula (1) or a salt thereof”, “a compound represented by the formula (2) or a salt thereof”, “ The “compound represented by (3) or a salt thereof” includes “a compound represented by formula (1)”, a “compound represented by formula (2)”, and a “compound represented by formula (3)”, respectively. "For convenience.

  First, each component contained in the composition of the present invention will be described. The composition of the present invention comprises (A) at least one dichroic dye, (B) polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether and polyoxyethylene tribenzyl. A composition comprising at least one surfactant selected from the group consisting of phenyl ethers and a solvent (C), wherein the HLB value of the surfactant is 12.5 or more and 17.5 or less. .

(A) Dichroic Dye 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 polarizability by being arranged in a certain direction by itself or in an aggregate.As such a dichroic dye, for example, an azo dye, a stilbene dye, a pyrazolone dye, Dye compounds such as triphenylmethane dye, quinoline dye, oxazine dye, thiazine dye, and anthraquinone dye are exemplified. The dichroic dye used in the present invention is a compound exhibiting lyotropic liquid crystallinity under a certain solvent composition, dye concentration and temperature condition. For example, supervised by Masahiro Irie, "Application of Functional Dyes", first edition published Edition, CMC Corporation, June 2002, pp. 102-104. As the dichroic dye, a water-soluble azo dye is preferably used, and among them, a compound having an aromatic ring structure is more preferable. As the aromatic ring structure, for example, besides benzene, naphthalene, anthracene, phenanthrene, a heterocyclic ring such as thiazole, pyridine, pyrimidine, pyridazine, pyrazine, quinoline or a quaternary salt thereof, furthermore, benzene, naphthalene or the like In particular, a sulfonic acid group, a carboxylic acid group, an amino group, a hydrophilic substituent such as a hydroxyl group, or a salt of a sulfonic acid group or a carboxylic acid group is introduced into these aromatic rings. Is preferred.

  Specific examples of such dichroic dyes include, for example, C.I. I. Direct Orange 39, C.I. I. Direct Orange 41, C.I. I. Direct Orange 49, C.I. I. Direct Orange 72, C.I. I. Direct Red 2, C.I. I. Direct Red 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. 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 15, C.I. I. Direct Blue 67, C.I. I. Direct Blue 78, C.I. I. Direct Blue 83, C.I. I. Direct Blue 90, C.I. I. Direct Blue 98, C.I. I. Direct Blue 151, C.I. I. Direct Blue 168, C.I. I. Direct Blue 202, C.I. I. Direct Green 42, C.I. I. Direct Green 51, C.I. I. Direct Green 59, C.I. I. Direct Green 85, C.I. I. Direct Yellow 4, C.I. I. Direct Yellow 12, C.I. I. Direct Yellow 26, C.I. I. Direct Yellow 44, C.I. I. Direct Yellow 50, Mordant Yellow 26, C.I. I. No. 27865, C.I. I. No. 27915, C.I. I. No. 27920, C.I. I. No. 29058, C.I. I. No. 29060 and the like, and further, JP-A-1-161202, JP-A-1-172906, JP-A-1-172907, JP-A-1-183602, JP-A-1-248105, and JP-A-1 And dichroic dyes described in JP-A-265205 and JP-A-9-230142.

  Among the dichroic dyes shown in the above specific examples, a compound represented by the following formula (1) or (2) is particularly preferable, and a compound represented by the formula (1) is particularly preferable. The compounds represented by the formulas (1) and (2) exist as a free acid or a salt 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, and K, and a quaternary ammonium salt. By using such a dichroic dye, the polarizing performance of the obtained polarizing element can be improved.

（式（１）中、
Ｘ_１は、１つ若しくは２つのスルホン酸基と、水酸基若しくは炭素数が１乃至３のアルコキシ基を有するフェニル基又はナフチル基を表し、
Ｘ_２及びＸ_３は、それぞれ独立して、フェニレン基又はナフチレン基を表し、当該フェニレン基又はナフチレン基は、炭素数が１乃至３のアルキル基、炭素数が１乃至３のアルコキシ基、水酸基及びスルホン酸基からなる群から選択される１種又は２種の置換基を１つ又は２つ有しており、
Ｒ_１は、水素原子、炭素数が１乃至３のアルキル基、アセチル基、ベンゾイル基、或いは、非置換のフェニル基又は炭素数が１乃至４のアルキル基、炭素数が１乃至４のアルコキシ基、アミノ基、スルホ基若しくは炭素数が１乃至４のアルキル基を有するアミノ基で置換されたフェニル基を表し、
ｍは、０又は１であり、かつ
ｎは、１又は２である。）

(In equation (1),
X ₁ represents one or two sulfonic acid groups and a phenyl group or a naphthyl group having a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms,
X ₂ and X ₃ each independently represent a phenylene group or a naphthylene group, and the phenylene group or the naphthylene group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, It has one or two kinds of one or two kinds of substituents selected from the group consisting of sulfonic acid groups,
R ₁ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A phenyl group substituted by an amino group having an amino group, a sulfo group or an alkyl group having 1 to 4 carbon atoms,
m is 0 or 1, and n is 1 or 2. )

（式（２）中、
Ｙ_１は、スルホン酸基を１つ又は２つ有し、さらに水酸基又は炭素数が１及至３のアルコキシ基を有していてもよいナフチル基を表し、
Ｙ_２及びＹ_３は、それぞれ独立して、フェニレン基又はナフチレン基を表し、当該フェニレン基又はナフチレン基は、炭素数が１及至３のアルキル基、炭素数１及至３のアルコキシ基、水酸基及びスルホン酸基からなる群から選択される１種又は２種の置換基を１つ又は２つ有しており、
Ｒ_２は、水素原子、炭素数が１及至３のアルキル基、アセチル基、ベンゾイル基、或いは、非置換のフェニル基又は炭素数が１乃至４のアルキル基、炭素数が１乃至４のアルコキシ基、アミノ基、スルホ基若しくは炭素数が１乃至４のアルキル基を有するアミノ基で置換されたフェニル基を表し、
フェニルアゾ基としての

は、末端ナフチル基の５位、６位、７位又は８位のいずれかに置換されており、
Ｒ_３及びＲ_４は、それぞれ独立して、水素原子、水酸基、スルホン酸基、炭素数が１及至３のアルキル基又は炭素数が１及至３のアルコキシ基を表し、
ｑは、０又は１であり、かつ
ｐは１又は２である。）

(In equation (2),
Y ₁ represents one or two sulfonic acid groups, and further represents a hydroxyl group or a naphthyl group which may have 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 the naphthylene group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, and a sulfone. Having one or two of one or two substituents selected from the group consisting of acid groups,
R ₂ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A phenyl group substituted by an amino group having an amino group, a sulfo group or an alkyl group having 1 to 4 carbon atoms,
As a phenylazo group

Is substituted at any of the 5-, 6-, 7- or 8-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 and p is 1 or 2. )

等が挙げられる。Specific examples of the compound represented by the above formula (1) include, for example,

And the like.

等が挙げられる。Specific examples of the compound represented by the formula (2) include, for example,

And the like.

Among the compounds represented by the formula (1) or the formula (2), X ₁ in the formula (1) or Y ₁ in the formula (2) is a compound represented by the following formula (3) as a substituent. By having the compound, the polarization performance can be further improved. In particular, in view of having a high dichroic ratio alone, the compound is represented by the formula (1) having a compound represented by the following formula (3) as a substituent. The use of compounds is preferred. The substituent also exists as a free acid or a salt thereof, similarly to the compounds represented by the 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, and K, and a quaternary ammonium salt.

（式（３）中、ｊは１又は２である。）

(In the formula (3), j is 1 or 2.)

  The dichroic dye of the present invention may be used alone or in combination of two or more. The combination of two or more dichroic dyes is not particularly limited, but by using an additional dichroic dye, it is possible to further improve the dichroic ratio of the dichroic dye. it can. Further, the total content of all dichroic dyes contained in the composition of the present invention is not particularly limited, but in order to impart high anisotropy to the dye film, the following solvent (C) The total amount is 0.1 to 15 parts by mass, preferably 0.3 to 10 parts by mass, and more preferably 0.5 to 7 parts by mass with respect to 100 parts by mass.

(B) Surfactant The composition of the present invention comprises a polyoxyethylene alkyl ether, a polyoxyethylene alkylene alkyl ether, a polyoxyethylene distyrenated phenyl ether and a polyoxyethylene tribenzyl as other components in the production of the dye film. It contains at least one surfactant selected from the group consisting of phenyl ethers and having an HLB value of 12.5 or more and 17.5 or less. By using such a surfactant, it is possible to improve coating defects that have conventionally occurred during coating in the preparation of a dye film on a substrate. Further, in the method for manufacturing a polarizing element described in Patent Document 2, in order to reduce shear stress parallel to the substrate at the time of coating, a specific pressure is applied between the roll and the substrate in manufacturing the polarizing element. Although the pressure had to be adjusted, such a special step becomes unnecessary when the composition of the present invention is applied to a substrate, because the composition of the present invention contains a specific surfactant. . Further, even if the composition of the present invention is applied to a rubbed substrate, a substrate provided with a photo-alignment film, a substrate damaged by friction, or a stretched substrate, the obtained dye is obtained. Uncoated portions that can be visually observed, for example, having a size of 50 μm or more in the film, 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, it is not possible to improve coating defects occurring in the dye film, while if the HLB value is more than 17.5, the dichroic dye is oriented in the dye film. You will not be able to do it. Specific examples of the polyoxyethylene alkyl ether having the above HLB value include, for example, Emulgen 1108 (having an HLB value of 13.4) manufactured by Kao Corporation and Emulgen 1118S-70 (having an HLB value of 16.4) manufactured by Kao Corporation.

  The polyoxyethylene alkylene alkyl ether is particularly preferably a polyoxyethylene polyoxypropylene alkyl ether or a polyoxyethylene polyoxypropylene block polymer. Specific examples of the polyoxyethylene alkylene alkylene alkyl ether having the above HLB value include, for example, polyoxyethylene polyoxypropylene alkyl ether as Emulgen LS-106 (HLB value 12.5) manufactured by Kao Corporation and Emulgen LS manufactured by Kao Corporation -110 (HLB value 13.4), Kao Corporation's Emulgen LS-114 (HLB value 14.0), Kao Corporation's Emulgen MS-110 (HLB value 12.7), and polyoxyethylene polyoxypropylene block. As the polymer, for example, Newpole PE-68 (HLB value 15.7) manufactured by Sanyo Kasei Co., Ltd., Newpole PE-78 (HLB value 15.6) manufactured by Sanyo Kasei Co., Ltd. HLB value 15.5), New Pole PE-12 manufactured by Sanyo Chemical Industries, Ltd. 8 (HLB value 15.6). Among them, in particular, as polyoxyethylene polyoxypropylene alkyl ether, Kao Emulgen LS-106, Kao Emulgen LS-110, Kao Emulgen LS-114, Kao Emulgen MS-110 are preferable, As the polyoxyethylene polyoxypropylene block polymer, New Pole PE-68 manufactured by Sanyo Chemical Industries, Ltd. is preferable.

  Specific examples of the polyoxyethylene distyrenated phenyl ether having the above HLB value include, for example, Emulgen A-60 (having an HLB value of 12.8) manufactured by Kao Corporation and Emulgen A-90 (having an HLB value of 14.2) manufactured by Kao Corporation. 5). Specific examples of the polyoxyethylene tribenzylphenyl ether having the above HLB value include, for example, Emulgen B-66 (having an HLB value of 13.2) manufactured by Kao Corporation.

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

(C) Solvent The composition of the present invention contains a solvent as a coating solution. Such a solvent is not particularly limited as long as it can dissolve the dichroic dye to be used. For example, water, alcohols, ethers, pyridine, dimethylformamide (DMF), dimethylsulfoxide (DMSO) , N-methylpyrrolidinone (NMP), dimethylacetamide (DMAC), dimethylimidazoline (DMI), and the like. Among these, only one kind of solvent may be contained, or a plurality of solvents may be contained. You may. In particular, when a water-soluble dichroic dye is used, water or a mixed solvent with the above-mentioned organic solvent is preferably used if the solvent mainly contains water. The mixing amount of the organic solvent with respect to water is arbitrary, but is preferably 0 to 50% by mass, particularly preferably 0 to 20% by mass with respect to water.

  Next, a dye film and a polarizing element produced by using the composition of the present invention, and a method for producing them will be described. The dye film of the present invention is produced by applying the above composition to a substrate and then drying the composition. When the dye film of the present invention is formed on a substrate and used as a polarizing element, a laminate composed of the substrate and the dye film may be used as a polarizing element, and a protective layer or the like is further laminated on the surface of the dye film. The laminated body thus obtained may be used as a polarizing element. Examples of the base material used when forming the dye film of the present invention include a glass plate such as silica-based glass and hard glass, a quartz plate, a polysiloxane resin, an ABS resin, a cycloolefin resin, an acetal resin, and a ) Acrylic resin, cellulose acetate, cellulose acetate, chlorinated polyether, ethylene-vinyl acetate copolymer, fluorine resin, ionomer, methylpentene polymer, nylon, polyamide, polycarbonate, polyethylene terephthalate, polyester such as polybutylene terephthalate, polyimide, Polyamide, polyphenylene oxide, polyphenylene sulfide, polyallyl sulfone, polyarylate, polyethylene, polypropylene, polystyrene, polysulfone, cycloolefin resin, vinyl acetate resin, vinylide chloride Plastic plates and sheets (films) of various materials such as resin, AS resin, vinyl chloride resin, alkyd resin, allyl resin, amino resin, urea resin, melamine resin, epoxy resin, phenol resin, unsaturated polyester resin, silicone resin and polyurethane ), A photoactive molecule (commonly referred to as a photo-alignment film) as described in Patent Document 1 or Patent Document 2, or a film or plate on which these resins are laminated or coated, or silicon oxide, Substrates coated with metal oxides such as tin oxide, indium oxide, aluminum oxide, titanium oxide, chromium oxide, and zinc oxide, silicon nitride, silicon carbide, and the like are given. Further, a substrate (film) whose surface is coated with a metal thin film having high reflectivity can also be used as a base material. These substrates may be flat or curved. The thickness of the substrate is 1 μm to 500 μm, preferably 10 to 100 μm.

  By using such a substrate after rubbing, photo-alignment or stretching, the dye film of the present invention having a polarizing function can be formed. Rubbing refers to a method of rubbing a substrate with a specific cloth as described in JP-A-8-152515 and JP-A-2002-90743, and Japanese Patent Application Nos. 2012-015492 and 2012-064912. And a method of performing uniaxial polishing processing using an abrasive or a material containing an abrasive as described in (1). Photo-alignment refers to, for example, as described in Patent Document 1 or Patent Document 2, irradiating a polymer or polymer having a photoactive group (a material generally called a photo-alignment film) with polarized light. Then, the orientation, polymerization or decomposition of the photoactive molecule causes the molecule to exhibit anisotropy in a specific axis. Stretching means that a polymer or a substrate obtained from a resin is stretched by heating or the like, whereby molecules are oriented in a specific axis. Therefore, the dichroic dye applied on the substrate can be oriented by rubbing, photo-aligning or stretching the substrate.

By performing corona discharge treatment or ultraviolet irradiation on the above-described base material, the dichroic ratio of a polarizing element described later is improved, and the polarizing characteristics of the obtained polarizing element can be improved. The corona discharge treatment can be applied by using various commercially available corona discharge treatment machines as a device for performing the corona discharge treatment. In particular, the use of a corona treatment machine having an aluminum head is preferable. The condition of the corona discharge treatment is such that the energy density in one corona discharge treatment is about 20 to 400 W · min · m ⁻² , preferably about 50 to 300 W · min · m ⁻² . If one corona discharge treatment is not sufficient, two or more corona discharge treatments may be performed. Similarly, ultraviolet irradiation can be applied by using various commercially available ultraviolet irradiation devices. The wavelength of the ultraviolet light to be used is not particularly limited, but for example, far ultraviolet light of 300 nm or less is preferable. The ultraviolet irradiation is preferably performed in an oxygen stream, and the irradiation time of the ultraviolet light is sufficient for a few minutes at most.

  A composition of the present invention containing a dichroic dye (a solution containing a dichroic dye) is dropped on the surface of the above-described base material, and a uniform thickness is formed on the base material by a coater or a spin coating method. A coating film of a dichroic dye is provided. The method of providing the coating film of the dichroic dye is not particularly limited as long as a solution containing the dichroic dye can be applied. A method of immersion, a method of applying a dichroic dye solution with a bar coder, or the like, or a method of applying to a home or commercial use, such as a piezo system, a thermal system, or a bubble jet (registered trademark) system, using an ink jet printer application device. Method, a method of spin coating with a spin coater, roll coater coating, flexographic printing, screen printing, gravure printing, curtain coater coating, spray coater coating, etc., in particular, roll coater coating, curtain coater coating, spraying with a spray coater A coating method is preferred.

  The substrate coated with the dichroic dye solution is then dried to form a solid state dichroic dye layer, thereby obtaining the dye film of the present invention. Although the drying conditions differ depending on the type of solvent, the type of dichroic dye, the amount of the solution containing the applied dichroic dye, and the concentration of the dichroic dye, the drying temperature is preferably room temperature to 100 ° C, preferably. Is room temperature to 50 ° C., and the humidity is about 20 to 95% RH, preferably about 30 to 90% RH.

  The thickness of the dye film of the present invention is preferably thinner from the viewpoint of improving the polarization characteristics, and is, for example, preferably 0.001 to 10 μm, particularly preferably 0.05 to 2 μm. Further, in order to form the dye film of the present invention within such a thickness range, the thickness of the coating film coated with a solution containing a dichroic dye is preferably 2 to 10 μm, and preferably 3 to 10 μm. More preferably, it is 5 μm.

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

  The dye film of the present invention thus obtained can be used as a polarizing element. The polarizing element of the present invention has a dichroic ratio (Rd), which 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). When the dichroic ratio is 5 or more, it means that a polarizing function is exhibited. 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 further 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 required to be 65% or more, preferably 70% or more, and more preferably 80% or more. The degree of polarization is the ratio of the light intensity of the polarized component to the total light intensity, and the higher the degree of polarization, the higher the polarization performance. In the following formula (4), Ky is the transmittance of the axis that transmits light the most when polarized light is incident, and Kz is the transmission of the axis that absorbs the light the most when polarized light is incident. Rate.

  As a method of further improving the dichroic ratio of the polarizing element of the present invention, with respect to the surface of the stretched film serving as a substrate, in the same direction as the stretching axis of the film, it was applied to the surface of the stretched film By expressing a molecular anisotropy larger than the molecular anisotropy, the dichroic ratio can be further improved. As a method of expressing a molecular anisotropy larger than that of a stretched film, for example, a method of rubbing a stretched film can be mentioned. Such rubbing is exemplified in, for example, JP-A-06-110059 and JP-A-2002-90743. The measurement of the molecular anisotropy of the surface of the stretched film is not particularly limited, but is measured by, for example, a measurement method used for anchoring measurement of the alignment film for liquid crystal. Also, the apparatus for measuring such molecular anisotropy is not particularly limited. For example, a Ray Scan manufactured by MARITEX SCOTT can be used.

  It is also possible to produce a polarizing element exhibiting molecular anisotropy in the major axis direction on the surface of a film having a phase difference axis (slow axis or fast axis) at an angle different from the major axis direction of the film. Specifically, by giving 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 major axis direction of the film, the polarizing axis or the absorption axis of the polarizing element can be arbitrarily set. Can be controlled. In other words, by using a stretched film having a phase difference axis at an angle different from the angle with respect to the major axis direction of the film and exhibiting molecular anisotropy on the surface in the major axis direction, a stretched film serving as a base material It is possible to produce a polarizing element having a phase difference axis and an absorption axis or a polarization axis at an angle different from the phase difference axis. The angle between the retardation axis of the stretched film serving as the base material 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 preferable is that, in general, when it is desired to control linearly polarized light into circularly polarized light, a film having a phase difference of ４ with respect to the length of the wavelength to be controlled is provided with an absorption axis of the polarizing element. It is known to be installed at 45 ° to As a method of reversing the polarization axis of linearly polarized light, it is known to install a film having a phase difference of １ ／ at 90 ° with respect to the length of the wavelength to be controlled. The reason why the film is set at 15 ° or 75 ° with respect to the absorption axis or the polarization axis of the polarizing element is that such an angle indicates a phase difference of １ ／ for a wide range of wavelengths ( This is because it is an axis angle used in a broadband achromatic phase difference plate. This makes it possible to arbitrarily control the polarization axis or the absorption axis of the polarizing element.

  Although the dye film of the present invention prepared as described above is in a solid state such as amorphous or crystalline, the dye film is generally inferior in mechanical strength, so that the surface of the dye film is raked, silane-coupled. A crosslinking treatment with an agent or a protective layer is provided. The lake treatment is to electrically couple a metal ion or the like to a water-soluble dichroic dye. Making a dichroic dye lake is sometimes referred to as lake formation or insolubilization. Compounds suitable for lakes include aluminum chloride, iron chloride, calcium chloride, barium chloride, nickel chloride, magnesium chloride, copper chloride, barium acetate, nickel acetate, etc. The dichroic dye is not particularly limited as long as the dichroic dye can be insoluble in water. The crosslinking treatment with the silane coupling agent is not particularly limited, for example, using a silane coupling agent as described in JP-A-2011-53234, the crosslinking treatment by heating or the like, The dye film can be immobilized. The protective layer is usually provided by a coating method such as coating a dye film with a transparent polymer film such as an ultraviolet curable or thermosetting polymer, or laminating a transparent polymer film such as a polyester film or a cellulose acetate film. . The protective layer can be provided as a coating layer of a polymer or as a laminate layer of a film. As the transparent polymer or film forming the transparent protective layer, a transparent polymer or film having high mechanical strength and good thermal stability is preferable. As the material used as the transparent protective layer, for example, cellulose acetate resin such as triacetyl cellulose or diacetyl cellulose or its film, acrylic resin or its film, polyvinyl chloride resin or its film, nylon resin or its film, polyester resin or its A film, a polyarylate resin or a film thereof, a cyclic polyolefin resin having a cyclic olefin such as norbornene as a monomer or a film thereof, polyethylene, polypropylene, a polyolefin having a cyclo or norbornene skeleton or a copolymer thereof, a main chain or a side chain is Examples include imide and / or amide resins or polymers or films thereof. In addition, a resin having liquid crystallinity or a film thereof can be provided as the transparent protective layer. The thickness of the protective layer is, for example, about 0.5 to 200 μm. A resin or film serving as a protective layer can be provided on one side or both sides of the polarizing element, and when using a plurality of protective layers, these protective layers may be the same or different. Is also good.

  The polarizing element of the present invention can be used for polarized sunglasses, goggles, and the like. In the manufacturing process of the polarizing element of the present invention, it is possible to give a gradation having a light and shade, or a pattern having many polarization axes. A gradation display polarizing element or a polarizing plate to which gradation is imparted can be manufactured by using a linearly polarized light through a mask pattern having shading or a photographic negative film when printing a polarization pattern on the photoactive molecular layer. Further, a multiaxial polarizing element or a polarizing plate having a large number of polarization axes can be manufactured by irradiating different portions with linearly polarized light having different polarization axes when printing a polarization pattern on the photoactive molecular layer. Such an additional function can be provided only by applying a solution containing a dichroic dye, as compared with a case where a normal polyvinyl alcohol-based film is used. Can be obtained. The fact that there is no dimensional change is particularly effective for a display such as a flexible display or an organic electroluminescence display (commonly called OLED) which requires a polarizing element to be provided on one side. Further, unlike conventional polarizing plates, difficult conditions are not required for coating a dye, and a desired polarizing element can be easily obtained simply by coating. Therefore, the manufacturing of the polarizing element is very simple.

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

  The transmittance at each wavelength was measured using a spectrophotometer (“U-4100” manufactured by Hitachi, Ltd.). The transmittance at each wavelength when one dye film is measured is defined as transmittance Ts, and the transmittance when two dye films are stacked so that their absorption axis directions are the same is the parallel transmittance Tp. The transmittance when two dye films were stacked so that their absorption axes were orthogonal to each other was defined as orthogonal transmittance Tc.

  The degree of polarization ρ was obtained from the parallel position transmittance Tp and the orthogonal position transmittance Tc by Expression (5).

  The dichroic ratio (Rd) was measured using JASCO Corporation V-7100, and the obtained value was used as the measurement result.

Example 1
Roll of 100 μm-thick polyethylene terephthalate film (Toyobo A-4100; hereinafter abbreviated as “PET film”) with a rubbing cloth (MK0012 manufactured by Myonaka Pile Woven Co., Ltd.) wound on the non-easy-adhesion treated surface as a substrate The rubbing treatment was performed at a speed of 100 rpm with a load of 5 kgf. C. as a dichroic dye on the rubbed PET film surface. I. Direct Blue 67, 5 parts by mass, 0.1 parts by mass of polyoxyethylene polyoxypropylene alkyl ether (Emulgen LS-106 manufactured by Kao Corporation: HLB value 12.5) as a surfactant, and 100 parts by mass of water as a solvent. The fermentation composition was applied using a coating machine provided with a glass rod set so that the distance from the PET film was 3 μm. The obtained coating film was left for 1 minute in an environment at 25 ° C. and a humidity of 70%, and the solvent was dried. Further, the dried coating film was heated and humidified for 5 minutes in an environment of 60 ° C. and 90% humidity to obtain a dye film of the present invention formed only of dye molecules. An acrylic resin-based ultraviolet curable resin composition (SPC-920C manufactured by Nippon Kayaku Co., Ltd.) is applied on the obtained dye film by a spin coater so that the thickness of the protective layer after curing becomes 3 μm. Then, the resin composition was cured by irradiating ultraviolet rays, and a protective layer was provided on the dye film. The polarizing element thus obtained was used as a measurement sample.

Example 2
The emulgen LS-106 as a surfactant used in Example 1 was changed to a polyoxyethylene polyoxypropylene alkyl ether having an HLB value of 12.7 (Emulgen MS-110 manufactured by Kao Corporation), and the content thereof Was measured in the same manner as in Example 1 except that was changed to 0.05 parts by mass.

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

Example 4
Example 1 Except that emulgen LS-106 as a surfactant used in Example 1 was changed to polyoxyethylene polyoxypropylene alkyl ether having an HLB value of 12.7 (Emulgen MS-110 manufactured by Kao Corporation). A measurement sample was prepared in the same manner as in Example 1.

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

Example 6
The emulgen LS-106 as a surfactant used in Example 1 was changed to a polyoxyethylene polyoxypropylene alkyl ether having an HLB value of 12.7 (Emulgen MS-110 manufactured by Kao Corporation), and the content thereof Was changed to 1.0 part by mass, and a measurement sample was prepared in the same manner as in Example 1.

Example 7
The PET film as the substrate used in Example 1 was changed to a triacetyl cellulose film (TD-80U, manufactured by Fuji Film Co., Ltd.) having a thickness of 80 μm. C. as a dye I. The content of Direct Blue 67 was changed to 10 parts by mass, and emulgen LS-106 as a surfactant was replaced with a polyoxyethylene polyoxypropylene alkyl ether having an HLB value of 12.7 (Emulgen MS-110 manufactured by Kao Corporation). A measurement sample was prepared in the same manner as in Example 1 except that the sample was changed to ()).

Example 8
Except that emulgen LS-106 as a surfactant used in Example 1 was changed to a polyoxyethylene polyoxypropylene glycol block polymer having an HLB value of 15.7 (Newpole PE-68 manufactured by Sanyo Chemical Industries, Ltd.). Prepared a measurement sample in the same manner as in Example 1.

Example 9
Same as Example 1 except that emulgen LS-106 as a surfactant used in Example 1 was changed to polyoxyethylene alkyl ether having an HLB value of 16.4 (Emulgen 1118S-70 manufactured by Kao Corporation). A measurement sample was prepared.

Example 10
In the composition used in Example 1, 4 parts by mass of C.I. I. Direct Blue 67 and 4 parts by weight of C.I. I. Emulgen LS-106 as a surfactant is used in combination with two types of dichroic dyes mixed with Direct Orange 72, and polyoxyethylene alkyl ether polyoxyethylene distyrenated phenyl ether having an HLB value of 14.5. (Emulgen A-90, manufactured by Kao Corporation) A measurement sample was prepared in the same manner as in Example 1 except that the content was changed to 0.2 parts by mass.

Example 11
Emulgen A-90 as a surfactant used in Example 10 was changed to a polyoxyethylene alkyl ether polyoxyethylene distyrenated phenyl ether having an HLB value of 12.8 (Emulgen A-60 manufactured by Kao Corporation). Except for the above, a measurement sample was prepared in the same manner as in Example 10.

Example 12
Emulgen A-90 as a surfactant used in Example 10 was changed to polyoxyethylene tribenzylphenyl ether having an HLB value of 12.8 (Emulgen B-66 manufactured by Kao Corporation) and its content A measurement sample was prepared in the same manner as in Example 10, except that was changed to 0.1 parts by mass.

Example 13
4-Methacryloyloxyazobenzene was dissolved in benzene to form a 20% by mass solution, and the azobenzene was polymerized at 60 ° C. for 12 hours under degassing using azobisisobutyronitrile as an initiator. A solution comprising 10 parts by mass of the obtained polymer having azobenzene and 90 parts by mass of toluene was spin-coated on the PET film used in Example 1 so that the film thickness after drying became 0.1 μm. Then, the PET film substrate is dried by heating at 100 ° C. for 1 minute. An ultra-high pressure mercury lamp of 500 W / h is prepared, the irradiation light is set to visible light (> 400 nm) by a cut-off filter, and the light is converted to linearly polarized light via a polarizing plate. This linearly polarized light was irradiated onto the coated surface of the substrate placed parallel to the polarization axis of the polarizing plate at room temperature for 1 minute from a distance at which the distance from the coated surface was 50 cm. C. as a dichroic dye is applied on the surface of the substrate subjected to such a photo-alignment treatment. I. A composition containing 5 parts by mass of Direct Blue 67, 0.1 parts by mass of polyoxyethylene polyoxypropylene alkyl ether (Emulgen MS-110, manufactured by Kao Corporation: HLB value 12.7), and 100 parts by mass of water, Coating was performed using a coating machine provided with a glass rod set so that the distance from the substrate was 3 μm. The obtained coating film was left for 1 minute in an environment at 25 ° C. and a humidity of 70%, and the solvent was dried. Further, the dried coating film was subjected to a heat treatment and a humidification treatment for 5 minutes in an environment of 60 ° C. and 90% humidity to obtain a dye film of the present invention. The same protective layer as in Example 1 was provided on the obtained dye film. The polarizing element thus obtained was used as a measurement sample.

Comparative Example 1
The emulgen 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 having an HLB value of 12.1. A measurement sample was prepared in the same manner as in Example 1 except that the sample was changed to (Emulgen 108, manufactured by Kao Corporation) and used as a comparative sample.

Comparative Example 2
In the composition used in Example 1, C.I. I. The content of Direct Blue 67 was changed to 10 parts by mass, and the emulgen LS-106 as a surfactant was changed to the nonionic surfactant (Emulgen 108 manufactured by Kao Corporation) of Comparative Example 1, and the content was changed. The same dichroic dye aqueous solution as in Example 1 of Patent Document 1 was prepared in place of 1 part by mass, and a measurement sample was prepared in the same manner as in Example 1 to obtain a comparative sample.

Comparative Example 3
The emulgen LS-106 as the surfactant used in Example 1 was replaced with the anionic surfactant used in Preparation 1 of the associative dichroic dye film of Patent Document 2, that is, a polyolefin having an HLB value of 25. A measurement sample was prepared in the same manner as in Example 1 except that sodium oxyethylene lauryl ether sulfate (Emal 20C manufactured by Kao Corporation) was used as a comparative sample.

Comparative Example 4
A measurement sample was prepared in the same manner as in Example 1 except that emulgen LS-106 as the surfactant used in Example 1 was not used, and used as a comparative sample.

Comparative Example 5
Without using Emulgen LS-106 as a surfactant used in Example 1, C.I. I. A coating solution containing a dichroic dye using a coating machine provided with a glass rod set so that the content of Direct Blue 67 is changed to 2 parts by mass and the distance from the PET film is set to 7 μm. A dye film and a measurement sample were prepared in the same manner as in Example 1 except that was applied, and a comparative sample was prepared.

Comparative Example 6
Example 1 Except that emulgen LS-106 as a surfactant used in Example 1 was changed to polyoxyethylene distyrenated phenyl ether having an HLB value of 18.0 (Emulgen A-500 manufactured by Kao Corporation). A measurement sample was prepared in the same manner as in Example 1, and was used as a comparative sample.

Comparative Example 7
Same as Example 1 except that emulgen LS-106 as a surfactant used in Example 1 was changed to polyoxyethylene alkyl ether having an HLB value of 18.5 (Emulgen 1150S-60 manufactured by Kao Corporation). Then, a measurement sample was prepared as a comparative sample.

Comparative Example 8
Same as Example 1 except that emulgen LS-106 as the surfactant used in Example 1 was changed to a polyoxyethylene alkyl ether having an HLB value of 17.9 (Emulgen 1150S-70 manufactured by Kao Corporation). Then, a measurement sample was prepared as a comparative sample.

  Table 1 shows Ts, Tp, Tc, ρ, and Rd at the wavelength having the highest polarization degree obtained by measuring the samples obtained in Examples 1 to 13 and Comparative Examples 1 to 8. Further, the coatability of the obtained dye film was evaluated. Regarding coatability, when 10 or more uncoated portions with a size of 50 μm or more can be visually confirmed in a 10 cm square dye film, it is considered that a coating defect has occurred in the dye film. In Table 1, "x" indicates that coating failure occurred, and "o" indicates that coating failure did not occur.

  As is clear from the results in Table 1, the coating film produced using the composition of the present invention has poor coating even when the substrate is subjected to the rubbing treatment as in Examples 1 to 12. This indicates that the composition of the present invention is excellent in coatability and that a dye film with improved coating defects is obtained. Further, even when the substrate is subjected to a photo-alignment treatment as in Example 13, similarly to Examples 1 to 12, a composition having excellent coatability, and a dye film having improved coating defects are further improved. It can be seen that is obtained. Further, as shown in Examples 1 to 13, the polarizing element having the dye film of the present invention has a high degree of polarization (ρ) and a high dichroic ratio (Rd) in addition to a high transmittance (Ts). From the results, it can be seen that, in the present invention, the poor polarization of the polarizing element is also improved with the improved coating failure of the dye film.

  On the other hand, the samples of Comparative Examples 1 and 2 using a polyoxyethylene alkylene alkyl ether having an HLB value outside the range of the present invention as the surfactant, and having an HLB value outside the range of the present invention and specified in the present invention. In the sample of Comparative Example 3 using the non-surfactant and the sample of Comparative Example 4 not using the surfactant, coating failure occurred in the dye film. This indicates that the coating failure of the dye film of these samples was not improved, and that the polarizing element having the dye film also had poor polarization.

  As in Comparative Example 4, the sample of Comparative Example 5 using a composition containing no surfactant and having a relatively thick dye film was calculated from the parallel transmittance (Tp) and the orthogonal transmittance (Tc). The contrast of the polarizing element to be obtained is about 2, and the sample of Comparative Example 6 using the composition containing polyoxyethylene distyrenated phenyl ether whose HLB value is outside the range of the present invention, the HLB value of the present invention is The contrast of the samples of Comparative Examples 7 and 8 using the composition containing the polyoxyethylene alkyl ether which is out of the specified range was about 1. From this, it is understood that even if such a polarizing element is applied to a display, it becomes a polarizing plate that hardly exhibits the contrast of the display. Furthermore, the samples of Comparative Examples 5 to 8 have a degree of polarization (ρ) of less than 65% and a dichroic ratio (Rd) of less than 5, indicating that the function as a polarizing element is not sufficient.

  From the above results, the dye film prepared by using the composition of the present invention improves the coating failure at the time of coating a dye film obtained by applying a composition containing a conventional dichroic dye, As a result, it can be seen that a high-quality polarizing element excellent in polarization performance without polarization failure can be obtained.

The polarizing element of the present invention can produce a polarizing element by applying a solution containing a dichroic dye to a rubbed substrate, instead of a polarizing element using a polyvinyl alcohol resin film like a conventional polarizing element. Therefore, there is no need for processes such as swelling, dyeing, and stretching which were required in the conventional steps. In addition, since a polarizing element film can be formed using only a dichroic dye as a component having a polarizing function, an ultrathin polarizing element can be formed. Furthermore, since a polarizing element can be manufactured by applying a solution containing a dichroic dye, the shape of the polarizing element is not limited to a flat polarizing element such as a conventional polarizing plate, and a curved or spherical polarizing element is formed. It is also possible. In particular, although the conventional stretched film could only form a polarizing plate that transmits polarized light perpendicular to the stretching direction, the polarizing element of the present invention sets the orientation direction arbitrarily with respect to the rubbed substrate. Therefore, it is possible to form a polarizing element having a fine pattern or a polarizing property in an arbitrary direction.

Claims (8)

(A) a water-soluble azo dye as at least one dichroic dye ; and (B) a polyoxyethylene polyoxypropylene alkyl ether, a polyoxyethylene polyoxypropylene block polymer, a polyoxyethylene distyrenated phenyl ether and a polyoxyethylene. It contains at least one surfactant selected from the group consisting of ethylenetribenzylphenyl ether and (C) a solvent, and the HLB value of the surfactant is 12.5 or more and 17.5 or less. A composition comprising: The composition according to claim 1 , wherein the dichroic dye is a compound represented by the following formula (1) or a salt thereof.

(In equation (1),
X ₁ represents one or two sulfonic acid groups and a phenyl group or a naphthyl group having a hydroxyl group or an alkoxy group having 1 to 3 carbon atoms,
X ₂ and X ₃ each independently represent a phenylene group or a naphthylene group, and the phenylene group or the naphthylene group is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, It has one or two kinds of one or two kinds of substituents selected from the group consisting of sulfonic acid groups,
R ₁ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, an unsubstituted phenyl group, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A phenyl group substituted by an amino group having an amino group, a sulfo group or an alkyl group having 1 to 4 carbon atoms,
m is 0 or 1 and n is 1 or 2) 3. 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. 4.

(In the formula (3), j is 1 or 2.) The composition according to any one of claims 1 to 3 , wherein the total amount of the dichroic dye is 0.1 to 15 parts by mass with respect to 100 parts by mass of the solvent. The composition according to any one of claims 1 to 4 , wherein the solvent contains at least water. Dye film produced using the composition according to any one of claims 1 to 5. 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.