JP2954306B2 - Dye for anthraquinone-based polarizing film and polarizing film using the dye - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anthraquinone dye and a polarizing film containing the dye in an oriented state.

[Conventional technology]

Today, the most commonly used polarizing films are
A polyvinyl alcohol-based resin is used as a film substrate, and a polarizing property is imparted to this by a dichroic substance such as an iodine compound and / or an acid dye or a direct dye having a selected structure.

This type of polarizing film shows excellent polarizing performance,
The durability is insufficient, and usually, both sides of the film have moisture resistance, and at least one side is covered with a transparent film-like material (protective film) to maintain the durability. In other words, means for obtaining substantial durability by protecting the defects of the internal polarizing film (layer), which is essentially extremely poor in durability, with the protective films (layers) on both sides are taken.

In recent years, with the expansion of applications of liquid crystal display elements to vehicles, computers, industrial equipment, etc., the durability of polarizing films used as one element, especially the improvement of moisture resistance, weather resistance and heat resistance, has been increasing. There is a strong demand. 1 for this
As one improvement means, a polarizing film using a hydrophobic resin as a substrate has been proposed.
-84409 and JP-A-63-289502.

However, although such a polarizing film sufficiently satisfies the durability, in reality, it is not always satisfactory in terms of the polarizing property.

[Problems to be solved by the invention]

An object of the present invention is to provide an anthraquinone-based dye suitable for a polarizing film using a hydrophobic resin as a film base, and a polarizing film containing the dye in an oriented state.

[Means for solving the problem]

The present inventors have conducted intensive studies in view of such a situation, and as a result, have found a novel yellow dichroic dye having excellent polarization performance and excellent durability.

That is, the anthraquinone dye according to the present invention has the general formula (I) Wherein X ₁ , X ₂ , X ₃ and X ₄ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino group, Y represents a nitrogen atom or a methine group, and n
Represents an integer of 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆
May be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and R ₇ represents a hydrogen atom, and a group represented by the formulas (a) to (e). (In the formulas (a) to (e), R ₈ represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted pyridyl group, Represents a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group or a substituted or unsubstituted naphthyl group, and Z represents a group represented by NH, an oxygen atom or a sulfur atom). Is a dichroic dye having a novel anthraquinone skeleton.

The polarizing film according to the present invention, which achieves the above object, is characterized in that the anthraquinone dye is oriented and contained in a hydrophobic resin.

The reason why the dye of the present invention is suitable as a dye for a polarizing film is that an anthraquinone, which is a color forming matrix, has an aryl group and
= N- or -CH = CH-, whereby a linear rod structure having a longer molecular structure than the known anthraquinone dyes disclosed in JP-A-63-289502 is obtained. In addition, the coplanarity is easily maintained, and the polarization performance and the durability are remarkably improved.

The structure of the anthraquinone compound represented by formula (I) of the present invention will be described in detail.

Examples of the substituents X ₁ , X ₂ , X ₃ and X ₄ include a hydrogen atom, a base atom, a halogen atom such as a fluorine atom and a bromine atom, a hydroxyl group, an amino group, or an alkylamino group having 1 to 4 carbon atoms. Can be

Examples of the substituents R _{1 to} R ₆ include a halogen atom such as a hydrogen atom, a chlorine atom, a fluorine atom and a bromine atom, an alkyl group such as a methyl group, an ethyl group and a propyl group, and an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group. Groups.

As the substituent R ₇ , -CONHR ₈ , -COOR ₈ , Is mentioned.

R ₈ in the substituent R ₇ may be a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group which may be substituted with a halogen atom such as a fluorine atom, a base atom, a bromine atom, a cyclohexyl group, a pyridyl group, a biphenyl group, Examples include a phenyl group or a naphthyl group. Further, preferred examples of the alkyl group include an alkyl group having 1 to 8 carbon atoms, and examples of the alkoxy group include an alkoxy group having 1 to 8 carbon atoms.

Z includes NH, an oxygen atom or a sulfur atom.

n represents 0 or 1, but the sum of m and n is 1 or 2
Is preferred.

 The dye represented by the general formula (I) of the present invention has the following general formula:
Formula (II)[X in the formula (II)₁, X_Two, X_ThreeAnd X_FourIs defined by the general formula (I)
Represented by the following general formula:
(III)[In the formula (III), R₁Or R₇Is also defined by the general formula (I)
And Q is NH_Two, X R₉P −CH_Two−, (R₉O)₂(PO) -CH_Two-
Here R₉Represents a phenyl group, a methyl group, or an ethyl group, and X represents
Which represents a halogen atom] in a solvent.
It is.

The molar ratio of the anthraquinone derivative represented by the general formula (II) to the compound represented by the general formula (III) is preferably the number of moles of the general formula (III) when the total number of moles of the general formula (II) is 1. Is 0.5 to 1.5.

 In the general formula (III), Q is X R₉P −CH_Two-Again
Is (R₉O)₂(PO) -CH_TwoReacts a compound that is-
When using a base, the base may be NaOH, KOH, C
a (OH)₂, MgO, NaH, NH_FourInorganic substances such as OH, CH_ThreeONa,
CH_ThreeOLi, C_TwoH_FiveONa, C_FourH₉Alkoxides such as OK, CH_ThreeCOON
a, CH_ThreeCOOK, CH_ThreeCOONH_FourCarboxylates, such as diazabi
Nitrogenation of cycloundecene, piperidine, pyridine, etc.
Compound, CH_ThreeLi, C_FourH₉Li, C₆H_FiveMgBr, (C_ThreeH₇)_TwoSuch as NLi
And alkyl metal compounds.

The solvent is used in an amount of 1 to 100 times by weight the compound of the general formula (I).

Preferred solvents include dimethylformamide, dimethylsulfoxide, sulfolane, aprotic polar solvents such as dimethylimidazolidinone, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, chloronaphthalene, aromatic solvents such as nitrobenzene, methanol, ethanol, Alcohols such as propanol, and carboxylic acids such as acetic acid and propionic acid.

The reaction temperature is preferably from room temperature to 200 ° C.,
The reaction time is 1 to 20 hours.

In the production of the polarizing film of the present invention, the dye used can be used as it is, but is preferably purified using recrystallization or other purification means, and is used after being ground to several microns or less. Is preferred.

The polarizing film of the present invention contains at least one of the dyes, and several kinds can be selected and mixed to obtain a desired hue, particularly to obtain a neutral gray color polarizing film. . Further, it may contain a dye having dichroism other than the present invention, and in some cases, a dye having no dichroism, an additive such as an ultraviolet absorber, and other substances.

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 containing no hydrophilic group on the molecular structure, but preferably has thermoplasticity. Specific examples thereof include vinyl halide polymer, acrylic, polyolefin, polyamide, polyimide, polyester, polycarbonate, and polyethersulfone resins. Among them, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polyethylene bis-α, β- (2-chlorophenoxy) ethane which are particularly excellent in heat resistance, moisture resistance and transparency.
A resin composition containing at least 80% by weight or more of an aromatic polyester resin component such as 4,4'-dicarboxylate is preferred.

The amount of the dye to be used is determined in consideration of the coloring ability of the dye to the base resin, which is a hydrophobic resin as described above, and the thickness of the intended polarizing film. Visible light transmittance per 30-60
Adjust to be%. For example, if the thickness of the polarizing film is 30 to 200 μm, the amount of the dye based on the base resin is
It is in the range of 0.01 to 10% by weight.

To produce the polarizing film of the present invention, at least one selected from the base resin and the dye of the present invention, after melting and coloring with other dyes to be mixed as necessary,
It can be produced by molding into a film or sheet and stretching.

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

That is, a) a film produced by the above method, b) a protective film having excellent optical transparency and mechanical strength on one or both surfaces, for example, a protective film made of colored or uncolored glass or synthetic resin. A polarizing sheet or film provided with a film (layer); c) an adhesive applied to one or both sides for simplicity when applied to commonly used liquid crystal displays, window glasses or glasses, etc. And d) a polarizing film to which a transparent conductive film such as indium-tin oxide is added on the surface of the polarizing film by a known method such as vapor deposition, sputtering or coating. These can also be used as cell forming materials for liquid crystal display elements.

〔Example〕

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

The degree of polarization in the examples is a value measured by the following method. That is, the two polarizing films are superposed so that the stretching directions are parallel to each other, placed in the optical path of the spectrophotometer, and the light transmittance (T ₁₁ ) at the maximum absorption wavelength in the visible region measured and the stretching directions of the two polarizing films are orthogonal. The degree of polarization (V) was calculated from the light transmittance (T⊥) at the same wavelength, which was measured in an overlapping manner, using the following equation.

Example 1 10 g of 1-amino-anthraquinone-2-carboxaldehyde and 14 g of 2- (4'-aminobiphenyl) -5-methylbenzoxazole were refluxed and stirred in 200 ml of acetic acid for 8 hours. After cooling the reaction solution to room temperature, the precipitate was collected by filtration, washed with a small amount of acetic acid, then with N, N-dimethylformamide and methanol, and dried to obtain the following dye (20 g).

Elemental analysis value CHN Calculated value (%) 78.79 4.34 7.88 Actual value (%) 78.69 4.42 7.95 This dye was added to polyethylene terephthalate resin pellets so that the polarizing film had a single transmittance of 40%.
After uniform mixing, the mixture was melt-extruded and formed into a sheet having a thickness of about 200 μm. Using a tenter stretching machine
The film was stretched 5 times in the transverse direction at 80 ° C. and heat-treated at 150 ° C. for 1 minute to obtain a red polarizing film having a thickness of 100 μm. The degree of polarization at a maximum absorption wavelength of 525 nm was as excellent as 99.5%.

This polarizing film is 500
After being left for a while, substantially no change in hue and no decrease in the degree of polarization was observed. The shrinkage of the film was 1% or less in both the vertical and horizontal directions, and the film had good dimensional stability.

Example 2 4-diethoxyphosphonomethyl-4'-phenylcarbamoyl-biphenyl (8.5 g) in N, N-dimethylformamide solution (100 ml) was treated with sodium metal (9.2 g) in ethanol (100 ml).
, And stirred at room temperature for 30 minutes.
-Diamino-anthraquinone-2-carboxaldehyde (5.3 g) was added, and the mixture was stirred at room temperature for 4 hours. The precipitate was collected by filtration, washed with N, N-dimethylformamide, then with methanol, and dried to obtain the following dye (9.5 g). I got

Elemental analysis value CHN Calculated value (%) 78.49 4.70 7.85 Actual value (%) 78.50 4.61 7.77 Using this dye, film processing was carried out in the same manner as in Example 1 to obtain a red-purple polarizing film. The degree of polarization at the maximum absorption wavelength of 565 nm was 99.7%, and as a result of a durability test similar to that in Example 1, there was no decrease in the degree of polarization and good dimensional stability.

Examples 3 to 13 Various anthraquinone dyes shown in Table 1 were obtained in the same manner as in Examples 1 and 2. Structural formula and color tone of pigment
Table 2 shows the results of elemental analysis.

When a polarizing film was prepared using these dyes in the same manner as in Example 1 and Example 2, all of them had excellent polarizing performance.

Comparative Examples 1-2 In place of the dye synthesized in Example 1,
The following structural formula (A) disclosed in No. 289502,
A red polarizing film was obtained in the same manner as in Example 1 except that the dye represented by (B) was used.

The degree of polarization at a maximum absorption wavelength of 510 nm is (A) 80
%, (B) was 92%, which was inferior to the dye of the present invention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Tetrahedron Letty 31 (36), PP5189-92, 1990 (issued August 28, 1990) Zh. Obshch. Khim. , 55 (4), PP756-62, 1985 Chemical Abstracts, Vol. 70, Abstract No. 79160 (1969) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09B 23/00 C09B 55/00 C09K 19/60 G02B 5/30 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. The compound of the general formula (I) Wherein X ₁ , X ₂ , X ₃ and X ₄ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino group, Y represents a nitrogen atom or a methine group, and n
Represents an integer of 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆
May be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and R ₇ represents a hydrogen atom, and a group represented by the formulas (a) to (e). [In the formulas (a) to (e), R ₈ represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted pyridyl group, Represents a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group or a substituted or unsubstituted naphthyl group, and Z represents a group represented by NH, an oxygen atom or a sulfur atom). Dyes for anthraquinone-based polarizing films. 2. The compound of the formula (I) in a hydrophobic resin. Wherein X ₁ , X ₂ , X ₃ and X ₄ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an amino group or a lower alkylamino group, Y represents a nitrogen atom or a methine group, and n
Represents an integer of 0 or 1. R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆
May be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and R ₇ represents a hydrogen atom, and a group represented by the formulas (a) to (e). [In the formulas (a) to (e), R ₈ represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a substituted or unsubstituted phenyl group, a substituted or unsubstituted cyclohexyl group, a substituted or unsubstituted pyridyl group, Represents a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group or a substituted or unsubstituted naphthyl group, and Z represents a group represented by NH, an oxygen atom or a sulfur atom). A polarizing film comprising at least one dye for an anthraquinone-based polarizing film.