JPH0794609B2 - Anthraquinone dye and polarizing film using the dye - Google Patents

Description

The present invention relates to an anthraquinone dye and a polarizing film containing the dye in an oriented manner.

[Conventional technology]

The most commonly used polarizing film today uses a polyvinyl alcohol-based resin as a film substrate, and a dichroic substance such as an iodine compound and / or an acid dye or a direct dye having a selected structure is used to polarize the film. Is given. This type of polarizing film exhibits excellent polarization performance, but its durability is insufficient, and the durability is usually improved by covering both sides of the film with a film-like material (protective film) that has moisture resistance and at least one side is transparent. Is held. That is, a means for obtaining practical durability by protecting the defects of the internal polarizing film (layer), which is inherently extremely poor in durability, with the protective films (layers) on both sides is taken.

Recently, with the expansion of applications for liquid crystal display devices such as in-vehicle devices, computers, industrial equipment, etc., it is possible to improve the durability of the polarizing film used as one element, especially the improvement of moisture resistance, weather resistance and heat resistance. There is a strong demand. 1 for this
As one of the improving means, a polarizing film using a hydrophobic resin as a substrate has been proposed, and as a known technique, JP-A-57-
No. 84409 and Nos. 58-68008 and 60-12 by the present inventors.
No. 5804 is exemplified. However, although such a polarizing film is sufficiently durable, it is not necessarily satisfactory in terms of polarizing property.

[Problems to be Solved by the Invention]

An object of the present invention is to provide an anthraquinone dye suitable for a polarizing film using a hydrophobic resin as a film substrate and a polarizing film containing the dye in an oriented manner.

[Means for Solving the Problems]

The anthraquinone dye according to the present invention which achieves the above object is an anthraquinone dye represented by the general formula (I). [In the formula, X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino having 1 to 4 carbon atoms. Group, Z ¹ and Z ² represent —N═CH—, —CH═CH—, or —COO—, and A represents an aromatic bifunctional group represented by any of formulas (IIa) to (IIc). Sexual group (In the above formula, R _{1 to} R ₄ each independently represent a hydrogen atom, a halogen atom, a methyl group, a hydroxyl group or a methoxy group)], and the dye has a color-forming group at both ends of the molecule, Is a compound in which is linked by a linking group and an aromatic bifunctional group that maintain the planarity and linearity of the molecule. The compound in which A is (IIa) or (IIb) is a novel anthraquinone dye.

As the linking group represented by Z ¹ and Z ² , -N = CH-, -CH
═CH— or —COO— and the like, particularly —N═CH
-Or-CH = CH- is preferred.

The aromatic bifunctional group represented by A is an aromatic group having a bond of Z ¹ and Z ² in the long axis direction of the group, and a preferable specific example thereof is: Etc. In addition, β expressed by the formula (III)
Anthraquinonyl group having the linking group Z ¹ or Z ² at the position [In the formula, X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino group having 1 to 4 carbon atoms. Which represents a group] Etc.

The anthraquinone dye of the present invention is a dichroic dye having a structure suitable for a polarizing film having a hydrophobic resin as a base material.

The reason why the dye of the present invention is suitable as a dye for a polarizing film is that the structure of the molecule is a long linear rod-like structure, the aromatic rings constituting the molecule are easy to keep in the same plane, and have a long conjugation. It is presumed that this is because it is possible to arrange the molecules parallel to the oriented film-constituting molecules by having a linking group and a functional group that interact with.

To synthesize the dye [general formula (I)] of the present invention, one or two kinds of anthraquinone derivatives represented by the following general formula (IV), [In the formula, X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino group having 1 to 4 carbon atoms. Group, Z ³
Represents -CHO or -COCl] It is obtained by reacting a compound represented by the following general formula (V) in the presence of a solvent.

Z ⁴ -A-Z ⁵ (V) [In the formula, A represents the same meaning as A in formula (I), Z ⁴ and Z ⁵ are each independently an amino group, a hydroxyl group, and X ^- R ₃ P. ⁺
—CH ₂ — or (RO) ₂ (PO) CH ₂ — (X is a halogen atom, R is a lower alkyl group) and the like, which are necessary for reacting with Z ³ to form the linking groups Z ¹ and Z ^2. Representing Reactive Group] The molar ratio of the anthraquinone derivative represented by the formula (IV) and the compound represented by the formula (V) is preferably such that when the total number of moles of the formula (IV) is 1 mole, The number of moles is 0.3 to 0.7.

The bases used are NaOH, KOH, Ca (OH) ₂ , M
Inorganic substances such as gO, NaH, NH ₄ OH, CH ₃ ONa, CH ₃ OLi, C ₂ H ₅
ONa, alkoxides such as C ₄ H ₉ OK, CH ₃ COONa, CH ₃ COOK,
Carboxylates such as CH ₃ COONH ₄ , nitrogen-containing compounds such as diazabicycloundecene, piperidine and pyridine, CH ₃ L
Alkyl metal compounds such as i, C ₄ H ₉ Li, C ₆ H ₅ MgBr, and (C ₃ H ₇ ) ₂ NLi.

As the solvent, 1 to 100 times by weight of the compound of the formula (I) is used. Preferred solvents include dimethylformamide,
Aprotic polar solvents such as dimethylsulfoxide, sulfolane, dimethylimidazolidinone, benzene, toluene, xylene, chlorobenzene, dichlorobenzene,
Aromatic solvents such as chloronaphthalene and nitrobenzene,
Alcohols such as methanol, ethanol and propanol, and carboxylic acids such as acetic acid and propionic acid.

Further, the reaction temperature is preferably room temperature to 200 ° C., and the reaction time is 1 to 20 hours.

The dye used in the production of the polarizing film of the present invention may be used as it is crude, but it is preferably purified by recrystallization or other purification means, and it is pulverized to several microns or less before use. It is preferable.

The polarizing film of the present invention contains at least one of the above-mentioned dyes, and several types can be selected and mixed and used in order to obtain a desired hue, and particularly to obtain a polarizing film having a neutral gray color. Further, a dye having a dichroic property other than that of the present invention, a dye having no dichroic property, an additive such as an ultraviolet absorber, or another substance may be contained depending on the case.

The hydrophobic resin used in the polarizing film of the present invention is not particularly limited as long as it is an organic polymer compound having a linear structure that does not include a hydrophilic group in terms of molecular structure, and it is preferable that it has thermoplasticity. Examples thereof include vinyl halide polymer type, acrylic type, polyolefin type, polyamide type, polyimide type, polyester type, polycarbonate type and polyether sulfone type resins. Among them, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene bis-α, β- (2-chlorophenoxy) ethane-4,4 ', which are particularly excellent in heat resistance, moisture resistance and transparency,
A resin composition containing at least 80% by weight of an aromatic polyester resin component such as dicarboxylate is preferable.

The amount of the dye used with respect to the base resin which is a hydrophobic resin as described above is determined in consideration of the coloring ability of the dye and the thickness of the polarizing film to be obtained, but preferably one polarizing film obtained. Visible light transmittance per unit is 30 to 60%
Adjust so that For example, if the thickness of the polarizing film is
If it is 30 to 200 μm, the amount of the dye to the base resin is 0.0
It is in the range of 1 to 10% by weight.

In order to produce the polarizing film of the present invention, it is melted and colored with a base resin and at least one selected from the dyes of the present invention, and optionally other dyes to be mixed, and then formed into a film or sheet. Can be produced by stretching.

The polarizing film produced in this manner can be further processed into various forms of films and sheets for practical use depending on the application.

That is, a) a film produced by the above method as it is, b) a protective film having excellent optical transparency and mechanical strength on one or both sides, for example, a protective film made of colored or uncolored glass or synthetic resin. Polarizing sheet or film provided with a film (layer), c) A pressure sensitive adhesive is applied to one side or both sides for ease of application to commonly used liquid crystal displays, window glasses, glasses, etc. Shape, and d) vapor deposition on the surface of the polarizing film,
Examples thereof include those in which a transparent conductive film such as indium-tin oxide is added by a known method such as sputtering or coating method. These can also be used as a cell forming agent for liquid crystal display elements.

〔Example〕

Hereinafter, representative examples of the dye of the present invention and a polarizing film using the dye will be specifically described with reference to examples.

The degree of polarization in the examples is a value measured by the following method.
It That is, if the two polarizing films are stretched in parallel,
Visible area measured by placing as many layers as possible in the optical path of the spectrophotometer
Light transmittance at the maximum absorption wavelength (T ) And two biases
Same wave measured by stacking optical films so that the stretching directions are orthogonal to each other
The degree of polarization is calculated from the light transmittance (T⊥) at long distance using the following formula.
(V) was calculated.

Example 1 10 g of 1-amino-anthraquinone-2-carboxaldehyde and 3.7 g of benzidine in 21 ml of nitrobenzene
Stir at 0 ° C. for 4 hours. After cooling the reaction solution to room temperature, the precipitate was collected by filtration, washed with a small amount of nitrobenzene, then washed with N, N-dimethylformamide and methanol and dried to obtain 12 g of the following dye. mp300 ℃ or more Elemental analysis value C H N calculated value (%) 77.53 4.03 8.61 Measured value (%) 77.30 3.95 8.72 It was formed into a sheet having a thickness of about 200 μm by melt extrusion. This sheet was stretched 5 times in the transverse direction at 80 ° C using a tenter stretching machine and heat-treated at 150 ° C for 1 minute. Thickness 1
A red polarizing film with a thickness of 00 μm is obtained, and the maximum absorption wavelength is 540n.
The degree of polarization at m was 99.9%, which was excellent. When this polarizing film was left for 500 hours under the conditions of 80 ° C. and 90% relative humidity, no change in hue and a decrease in the degree of polarization were substantially observed. The shrinkage rate of the film was 1% or less in both the machine direction and the transverse direction, and the film had good dimensional stability.

Example 2 120 ml of N, N-dimethylformamide solution containing 9.1 g of 4,4'-bis (diethoxyphosphonomethyl) -biphenyl was added to a solution of 1.4 g of sodium metal in 40 ml of ethanol and stirred at room temperature for 30 minutes. Then, 10 g of 1-amino-anthraquinone-2-carboxaldehyde was added, and the mixture was stirred at room temperature for 4 hours.
Stir for hours. The precipitate was collected by filtration, washed with N, N-dimethylformamide and then with methanol, and dried to give the following dye 11
got g. mp300 ℃ or above Elemental analysis value C H N calculated value (%) 81.47 4.35 4.32 Measured value (%) 81.26 4.21 4.15 The film was processed in the same manner as in Example 1 to obtain a red polarizing film. The polarization degree at the maximum absorption wavelength of 530 nm is 99.9%, and as a result of the same durability test, there is no decrease in the polarization degree.
It had good dimensional stability.

Example 3 60 g of 1-amino-2-formylanthraquinone and 28 g of 2,6-diaminoanthraquinone were reacted with acetic acid 3 under reflux for 4 hours. The precipitated crystals were filtered while hot to obtain 70 g of the following dye.

Elemental analysis value C H N calculated value (%) 75.00 3.41 7.95 measured value (%) 74.93 3.40 7.89 This dye was processed into a film in the same manner as in Example 1 to obtain a red polarizing film. The polarization degree at the maximum absorption wavelength of 545 nm was 99.9%, and as a result of the durability test, it had good durability.

Example 4 0.7 g of metallic sodium was dissolved in 100 ml of ethanol. Four,
A solution of 2.3 g of 4'-bis (diethoxyphosphenomethyl) -biphenyl in N, N-dimethylformamide was added dropwise.
After reacting at room temperature for 1 hour, 3 g of 2-formylanthraquinone
An N, N-dimethylformamide solution was added dropwise and the reaction was carried out at room temperature for 2 hours. The crystals formed are filtered off and dried to give the following dye
Obtained 3.5 g.

Elemental analysis value C H calculated value (%) 85.42 4.24 Measured value (%) 85.71 4.01 This dye was film processed in the same manner as in Example 1 to obtain a yellow polarizing film. The degree of polarization at the maximum absorption wavelength of 445 nm was 99.9%, indicating good durability.

Examples 5 to 13 Various anthraquinone dyes shown in Table 1 were obtained in the same manner as in Examples 1 and 2. The structural formula and color tone of the dye are shown in Table 1, and the elemental analysis results are shown in Table 2. When a polarizing film was produced using these dyes in the same manner as in Example 1 and Example 2, all had excellent polarizing performance.

Comparative Example A dye of the following formula, which is disclosed in JP-A-60-125804, is It does not have the group of the present invention as a linking group, and the bifunctional direction group in the center of the molecule has a structure which is not suitable for maintaining the planarity and linearity of the entire molecule, and thus has a polarization property. Was also inferior to the dye of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C09B 55/00 B G02B 1/08 5/30

Claims (2)

[Claims] 1. A general formula (I) [In the formula, X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino having 1 to 4 carbon atoms. Group, Z ¹ and Z ² represent —N═CH—, —CH═CH—, or —COO—, and A represents an aromatic bifunctional group represented by formula (IIa) or (IIb). (Wherein R _{1 to} R ₃ each independently represent a hydrogen atom, a halogen atom, a methyl group, a hydroxyl group or a methoxy group)]. 2. A compound of general formula (I) in a hydrophobic resin. [Wherein, X ₁ , X ₂ , X ₃ , X ₄ , X ₅ , X ₆ and X ₇ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino group having 1 to 4 carbon atoms. Wherein Z ¹ and Z ² represent —N═CH—, —CH═CH—, or —COO—, and A is an aromatic bifunctional group represented by any of formulas (IIa) to (IIc). Sexual group (In the above formula, R _{1 to} R ₄ each independently represents a hydrogen atom, a halogen atom, a methyl group, a hydroxyl group or a methoxy group, and m is 1
To 6)] is contained] at least one kind of anthraquinone dye represented by