JPH01252905A - Polarizing film - Google Patents

Abstract

PURPOSE:To obtain the polarizing film with sufficient heat-resisting property and excellent polarizing characteristic by adsorbing a specified dyestuff to a polymer film and orientating the obtd. film. CONSTITUTION:A disazo dyestuff shown by formula I and/or a disazo metal complex dyestuff shown by formula II are incorporated in the polarizing film in which the dyestuff is adsorbed to the polymer film, and the obtd. film is orientated. In the formula, A and A' are each naphthyl group having SO3M group or phenyl group having a substituent group, M is hydrogen atom or a cation such as alkali metal, ammonium or amines, X and X' are each hydrogen or halogen atom, COOM, SO3M, alkyl, nitro or acylamino group, Y and Y' are each hydrogen atom or SO3M group, W is a metal atom such as Cu or Cr. Thus, the polarizing film with the heat-resisting property and the excellent polarizing property is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polarizing film, and more specifically, the present invention relates to a polarizing film, and more specifically, it is made by adsorbing and orienting a water-soluble dye to a polymer film, which has a neutral color and a high degree of polarization. The present invention relates to a polarizing film having the following characteristics.

[Conventional technology]

Conventionally, iodine has been used as a polarizing element to be included in a polarizing film, and recently, the use of organic dyes has also been considered.

[Problem to be solved by the invention]

However, the conventionally used iodine has a high sublimation property, so when it is included in a polarizing film as a polarizing element,
The heat resistance is insufficient, and conventional organic dyes have problems in that only polarizing elements can be obtained whose polarizing properties are considerably inferior to those of iodine.

The present invention solves the above-mentioned conventional problems and develops an organic dye polarizing element that has sufficient heat resistance and polarization ability comparable to the excellent polarization properties of conventional iodine. The purpose of the present invention is to provide a novel polarizing film containing.

[Means to solve the problem]

The inventors of the present invention have conducted intensive research to achieve the above object, and as a result, they have arrived at the present invention. That is, the present invention provides a polarizing film in which a dye is adsorbed and oriented on a polymer film, which has the following general formula (in the formula, "."' represents a naphthyl group having a 1803M group or a phenyl group having a substituent,
M represents a hydrogen atom, an alkali metal, ammonium or an amine cation. ) and/or a disazo dye represented by the general formula (1) (where x, x' are hydrogen atoms, C00M group, 503M
group, a halogen atom, an alkyl group, a group, or an acylamino group, Y and Y' represent a hydrogen atom or a 503M group, W represents a copper or chromium metal atom, and M represents a hydrogen atom, an alkali metal, or an ammonium atom. Or it represents a cation of amines. ) A polarizing film characterized by containing a disazo metal complex dye represented by:

Specific examples of dyes represented by foreleg general formula [1] and forefoot general formula [1] to be contained in the polarizing film of the present invention include foreleg general formulas [1] of A1 to A9 in Table 1 below. A total of 16 examples of disazo dyes and disazo metal complex salt dyes represented by the general formula (1) of No. 1 to A7 in Table 2 are listed.

The above-mentioned disazo dyes and disazo metal complex dyes (hereinafter abbreviated as the dyes of the present invention) used in the present invention are, for example, "New Dye Chemical" by Yutaka Hosoda (published by Gihodo Co., Ltd. December 21, 1972). Publication) Page 397, lines 27 to 398
It can be produced according to the method described in page 19, line 2 from the bottom of page 400 to page 401, line 18.

That is, for example, the disazo dyes shown in Table 1 above can be produced by repeating ordinary diazotization and coupling, and the disazo metal complex dyes shown in Table 2 can be produced by first producing ordinary diazo dyes. Each disazo dye that serves as the base material is manufactured by repeating oxidation and coupling,
This can be produced by converting it into a metal complex salt using a conventional method.

Although these dyes can be used alone, it is preferable to use them in combination, since the degree of polarization will also be increased. In addition,
The polarizing film of the present invention can sufficiently polarize light in the wavelength range of 460 to 600 nm by using the dye of the present invention described above, but in order to perfect the degree of polarization in a wider wavelength range, the following The use of supplementary pigments is ■
C, 1, Direct Yellow 14z■ C
0I, Ac1d Yellow 25 (Dye Handbook page 396) ■ C, 1, Ac1d Orange
28 (Ibid. p. 411) ■ C, 1, Aeid
Orange 43 (same as above, p. 412) ■
C, 1, Ae id Orange 19 (same as above, p. 410) ■ C, I, Ae id Green
25 (Same as above, p. 490) (Note) Edited by the Organic Synthetic Chemistry Society, "New Edition Dye Handbook", published by Maruzen Co., Ltd. All of the above dyes from ■ to ■ are water-soluble, and ■ to ■ are azo-based compounds, and ■ are anthraquinone-based compounds.

The polymer film used in the polarizing film of the present invention is preferably a hydrophilic polymer film, and specific examples of the material include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, or combinations thereof with ethylene, propylene, acrylic acid, etc. , those modified with maleic acid acrylamide and the like, cellulose resins, and the like. These high molecular weight polymers have good solubility in water or hydrophilic organic solvents, have good compatibility with the dye of the present invention, and have excellent film forming properties and can be stretched and oriented after film forming. The dye of the present invention is particularly useful in that it is easily oriented when the dye is oriented.

The method for producing the polarizing film of the present invention using the above-mentioned polymer and the dye of the present invention includes a method of forming a polymer into a film and dyeing it, or a method of dyeing the film after forming the polymer into a film, or using a solution of the polymer. Examples include a method in which the dye of the present invention is added and a film is formed after dyeing with a stock solution.

The above-mentioned dyeing, film forming, and stretching can generally be performed by the following methods.

In a dye bath containing the dye of the present invention and, if necessary, dyeing aids such as sodium chloride, inorganic salts such as sulfur salt, and surfactants, at 20° to 80°C, preferably 30' to 50°C, ~6
The polymer film is immersed for 0 minutes, preferably 3 to 20 minutes to dye, then optionally treated with boric acid and dried.

Alternatively, the high molecular weight polymer is dissolved in water and/or a hydrophilic organic solvent such as alcohol, glycerin, dimethylformamide, etc., and the dye of the present invention is added to perform stock solution dyeing, and this dye stock solution is used by casting or solution coating. A dyed film is produced by forming a υ film by a method such as a method or an extrusion method.

The concentration of the polymer dissolved in the solvent varies depending on the type of polymer, but is 5 to 30% by weight, preferably 10 to 200 to 20% by weight. In addition, the concentration of the dye of the present invention dissolved in the solvent varies depending on the type of polymer, the type of dye, the thickness of the film when formed, the required performance when used as a polarizing film, etc. 0.1 to 5% by weight, preferably 0.8 to 5% by weight based on the combined weight
It is about 25% by weight.

The unstretched film obtained by dyeing and film forming as described above is uniaxially stretched by an appropriate method. The stretching treatment orients the dye molecules and develops polarizing performance. - The axial stretching method includes a wet method for tensile stretching, a dry method for tensile stretching,
There are methods such as performing inter-roll compression stretching using a dry method, and any method may be used. The stretching ratio is 2 to 9 times, but when polyvinyl alcohol and its derivatives are used, a range of 25 to 6 times is preferred.

After the stretching and orientation treatment, boric acid treatment is performed for the purpose of improving the water resistance and polarization performance of the stretched film. Boric acid treatment improves the light transmittance and degree of polarization of the polarizing film. The conditions for boric acid treatment vary depending on the type of hydrophilic polymer used and the type of dye, but generally the boric acid concentration is 1 to 15% by weight, preferably 5 to 10% by weight.
It is desirable that the weight percent and treatment temperature be in the range of 30 to 80°C, preferably 50 to 80°C. When the boric acid concentration is 1% by weight or less and the temperature is 30°C or less, the treatment effect is small;
If the temperature is 0° C. or higher, the polarizing film becomes brittle, which is not preferable.

The polarizing film produced in this way can be used after being subjected to various types of processing. For example, in addition to being used as a film or sheet, depending on the purpose of use, a protective layer may be formed by laminating with a polymer such as triacetate, acrylic, or urethane, or by vapor deposition, sputtering, or coating on the surface of the polarizing film. , a transparent conductive film of indium-tin oxide, etc. is formed and put to practical use.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples.

Further, in the following examples, the dye orientation number (Fdye) of the polyazo compound of the present invention was calculated by the following method.

Fdye = (D-1)/(D+2)...
...(1) Here, D is the absorption dichroic ratio of the dichroic dye-containing film and is based on the following formula (2).

D=Log(IO/l1l)/Log(IO/II)
+++++・+ (2) However, the transmittance of the undyed 7 film under the same stretching conditions and the same processing conditions is IO, and the transmittance values when the polarization plane of the incident light and the stretching axis are perpendicular and parallel are 11 and 11, respectively. Iil. The Fdye value represents the degree of orientation of the dichroic dye, and a positive Fdye value indicates that the polarizing performance of the polarizing film is positive.

In addition, in the examples, "parts" are "parts by weight".

Example 1 0.5 part of disazo dye in Table 1 Boiled 2, Table 2 4
Add 0.3 parts of the disazo copper complex dye of No. 1, 0.2 part of the disazo chrome complex dye of Table 2 & 4, and 25 parts of Glauber's salt to 10 parts of water.
A 4-fold stretched polyvinyl alcohol film (hereinafter abbreviated as "PvA film") with one side bonded and held with cellulose triacetate was dissolved in 0.00 parts and made into a dye bath at 40°C ± 1°C. After dyeing by dipping for 60 minutes and washing with water
A PVA film dyed gray was obtained by drying in a warm air dryer at .degree. This dyed film was placed on the sample side of a Hitachi 307 color analyzer, and a colorless uniaxially stretched PVA (cellulose triacetate adhesive support) film was placed on the compensation side, and the transmittance of the two parallel films and the two orthogonal films was measured. did.

As a result, the dyed film obtained was 460 to 6001
It shows almost flat absorption at m, and also shows (7)53
Fdye at 5 parts m was 0.92, indicating high polarization ability.

Example 2 A PVA film was stretched approximately 3.5 times in warm water at 40°C, and while the stretched state was maintained, 0.3 parts of the disazo dye of the first table 1 and the disazochrome of the table 2 & 7 were added. Complex dye 0.2 part, disazo dye of Table 1 & 9
0.2 part, C, 1, Direct Yellow
w 86 0.2 parts and C01,A
Dip dyeing was carried out in 800 parts of a dye bath containing 0.4 parts of c1d Green 25, followed by washing with water, treatment with boric acid water, and washing with water. After thoroughly removing water droplets on the membrane surface with paper, heat to 60°C.
A bluish-gray dyed film was obtained by drying in a hot air dryer.

Regarding this dyed film, the light absorption curve and transmittance were measured in the same manner as in Example 1.

As a result, the dyed film obtained was 390 to 7001
It shows almost flat absorption at 390 to 700 m.
The average Fdye in nm was 0.88.

Example 3 Average degree of polymerization i 700. Polyvinyl alcohol with a degree of saponification of 99.5% was dissolved in water, and 0.7 parts by weight of the disazo dye of Table 4 in Table 1 was added to the solution to completely and uniformly dissolve the polyvinyl alcohol. This mixed solution was cast onto a polyethylene terephthalate film to form a film and dried to obtain a film with a thickness of 55 μm. This film was placed in a hot air dryer at 150° C. and heat-treated for 10 minutes. This film was rolled vertically between a pair of rolls at 90°C.
After 4 times compression stretching on the shaft, 7.5% by weight of boric acid
After being immersed in a 65° C. aqueous solution for 5 minutes, the film was washed with 20° C. water for 1 minute, and dried to obtain a polarizing film.

The obtained polarizing film had an Fdye of 0.92 at 553 parts m, which shows the maximum absorption, and had a high polarizing ability.

〔Effect of the invention〕

As is clear from the above results, the polarizing film of the present invention not only has much better heat resistance than the conventional polarizing element made of iodine, which easily sublimes, due to the polarizing element made of water-soluble organic dye, which is difficult to sublimate. By using a specific water-soluble organic dye, most of the dye orientation coefficients (Fdye) are 0.88 or more, and all of them have industrial value as they show polarizing ability comparable to conventional polarizing films using iodine. This has a remarkable effect.

Patent applicant: Mitsubishi Chemical Industries, Ltd. Agent: Patent Attorney Tsunebe Ogawa

Claims (1)

[Claims] (1) In a polarizing film made by adsorbing and orienting a dye on a polymer film, the following general formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] (In the formula, A and A' are Represents a naphthyl group having a SO_3M group or a phenyl group having a substituent, M is a hydrogen atom,
Represents an alkali metal, ammonium or amine cation. ) and/or the general formula [
II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[II] (In the formula, X and X' are hydrogen atoms, COOM group, SO_3M
group, halogen atom, alkyl group, nitro group or acylamino group, Y and Y' represent a hydrogen atom or SO_3M group, W represents a copper or chromium metal atom, M represents a hydrogen atom, an alkali metal, ammonium or Represents a cation of amines. ) A polarizing film containing a disazo metal complex dye represented by: