JPH0213903A - Dyestuff type polarizing film - Google Patents

Abstract

PURPOSE:To obtain the title film which is hard to generate discoloration, even in a high temp. condition, and has a high performance by using a specified water soluble nickel, zinc or iron contg. disazo type direct dyestuff for a dichroic dyestuff. CONSTITUTION:The dichroic dyestuff is composed of the water-soluble nickel, zinc or iron contg. disazo type direct dyestuff shown by formula I. In formula I, Me is a transition metal atom and is composed of nickel (Ni), zinc (Zn) or iron (Fe), R1 and R2 each bind to an azo group at a position adjacent to a hydroxyl group which forms a compelx binding with the transition metal, and have 1-naphthol or 2-naphthol residual group, as a substituting group. The compd. shown by formula I has 1-3 numbers of sulfonic acid groups. Thus, the dystuff type polarizing film which has the high durability for a long period even at a high temp., and the high polarizing performance, is obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a highly durable and high-performance dye-based polarizing film.

[Prior Art and Problems to be Solved by the Invention] Currently, polarizing films are produced using stretched and oriented polyvinyl alcohol or derivatives thereof, or polyenes produced by dehydrochlorination of polyvinyl chloride films or dehydration of polyvinyl alcohol films. It is generally manufactured by adsorbing iodine or dichroic dye to a polyene film as a polarizing element.

Among these, polarizing films that use iodine as a polarizing element have excellent initial polarization performance, but are weak against water and heat (
When used for long periods of time in high temperature and high humidity conditions, there is a problem with its durability. In order to improve durability, we strengthen the treatment with formalin or an aqueous solution containing boric acid,
Also, a method of using a polymer film with low moisture permeability as a protective film has been considered, but this method has insufficient durability under high temperature and high humidity conditions.

In addition, although polarizing films that use dichroic dyes as polarizing elements are more durable against water and heat than polarizing films that use iodine, their polarizing performance is inferior to polarizing films that use iodine. . Furthermore, depending on the dye used, there are some that cause significant discoloration at high temperatures.

The present invention solves the above-mentioned problems of the conventional techniques and provides a high-performance polarizing film that is resistant to discoloration even at high temperatures.

[Failure to solve the problem]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems.

That is, the present invention provides a dye-based polarizing film in which a dichroic dye is adsorbed and oriented on a polymer film, in which the dichroic dye has the general formula (1) (where Me is a transition metal atom and nickel ( Ni
), or zinc (Zn), or iron (Fe). R1 and R2 are bonded to an azo group at a position adjacent to the hydroxyl group that is complex bonded to the transition metal, and further include as a substituent,
Indicates a 1-naphthol or 2-naphthol residue that can have a hydroxyl group not adjacent to a sulfonic acid group, sulfonamide group, amino group, acylamino group, allylamino group, or azo group. Therefore, formula (1) has 1 to 3 sulfonic acid groups. ) A dye-based polarizing film characterized by being a water-soluble nickel-, zinc-, or iron-containing disazo-based direct dye, or an organic direct dye having at least one type of said dye and absorption in a specific wavelength range. The present invention relates to a dye-based polarizing film exhibiting a neutral color, characterized in that it is used in combination with the dye-based polarizing film. By using the nickel-, zinc-, or iron-containing disazo direct dye, not only does it not cause discoloration at high temperatures, but it also has a wide light absorption range and improves the dichroism, or polarization performance, of the dye itself. It was discovered that a polarizing film with high durability and high polarizing performance never before seen could be obtained. It is particularly useful for producing polarizing films that exhibit neutral colors.

The nickel-, zinc-, or iron-containing disazo direct dye used in the present invention can be easily produced, for example, by the method described below.

The compound represented by the formula (D
) or (E) (wherein R1-R1 represents a hydrogen atom, a sulfonic acid group, a sulfonamide group, an amino group, an acylamino group, an allylamino group, or a hydroxyl group. However, R8 in formula (D) excludes a hydroxyl group. ) to obtain a disazo direct dye.

Examples of the compound of formula (D) used in the present invention include α
- Naphthol, NW acid, AW acid, AW acid amide, epsilonic acid, T-acid, phenyl-γ acid, J acid, phenyl J acid, benzoyl J acid, acetyl J acid, ■] acid, N-acetyl H acid, Examples include N-benzoyl H acid and chromotropic acid. Examples of the compound of formula (E) include β-naphthol, Scheffer's acid, Scheffer's acid amide, R acid,
Examples include G acid.

The water-soluble nickel-containing disazo direct dye, zinc-containing disazo direct dye, and iron-containing disazo direct dye used in the present invention can be obtained as follows.

That is, the disazo direct dye to be complexed is dissolved or dispersed in water or a hydrophilic solvent, such as a mixed solvent of ethylene glycol, methylcellosolves, and water, and then dissolved or dispersed in an alkaline environment, preferably with ammonia or monomer. In the presence of ethanolamine, jetanolamine, 50~
At a temperature of 100°C, preferably 90°C or higher, the desired water-soluble nickel-containing material is produced by reacting with an aqueous solution of nickel sulfate, nickel chloride, nickel acetate, zinc sulfate, zinc chloride, iron sulfate, iron chloride, etc. Disazo direct dyes, zinc-containing disazo direct dyes, and iron-containing disazo direct dyes can be obtained.

Further, according to the above-mentioned method, the disazo direct dye to be complexed is dissolved or dispersed in water or a mixed solvent of a hydrophilic solvent such as ethylene glycol or methylcellosolves and water, preferably in an alkaline state. by the action of an aqueous solution of copper sulfate, copper chloride, copper acetate, preferably copper tetraamine, at a temperature of 50 to 100 °C, preferably 90 °C or higher, in the presence of ammonia, or monoethanolamine or jetanolamine. A copper-containing disazo direct dye can be obtained. The copper-containing disazo direct dye obtained in this way is heated to remove copper in dilute hydrochloric acid, and a metal-incompatible o, o' dihydroxy disazo dye is used to form a nickel complex or a zinc complex as described above. The method of complexing or iron complexing can be advantageously carried out as a method of obtaining the desired nickel-, zinc-, or iron-containing disazo direct dye.

Specific examples of the water-soluble nickel-, zinc-, or iron-containing disazo dye represented by formula (1) thus obtained are shown in formulas (n) to (X12).

In formula (n), Me represents nickel (Ni), zinc (Zn), or iron (Fe).

Further, in the present invention, by using the dye represented by the general formula (1) together with an organic direct dye having absorption in a specific wavelength range, hue modification and improvement in polarization performance can be achieved. The organic direct dye used in this case is a dichroic dye that has absorption characteristics in a wavelength range different from the absorption wavelength range of the nickel, zinc, or iron-containing disazo direct dye used in the present invention. Any high-quality dye may be used, but it is generally selected from azo dyes. The organic direct dyes used in the present invention include:
Color index generic name (C,
I.

Generic Name) and product name,
Examples include the following:

Sea Eye Direct Yellow 12 (C, 1, Di
rect Yellow 12---Chrysophenine) C.I. Direct Blue 202 (C, 1, Di
rect Blue 202 --- Sumilight Spra Blue 3GS) C.I. Direct Red 31 (C, 1, Direct Red 31 --- Nirapon Fast Red BB Conch) C.I. Direct Violet 9 (C01 , Direct
Violet 9 --- Nirapon Brilliant
Violet B to Conch) C.I. Direct Yellow 44 (C, 1, Direct Yellow
44---Direct First Yellow Gc
) C.I. Direct Yellow 28 (C, 1, D
irect Yellow 28---Sumilite Splat Yellow BC Conch) C.I. Direct Orange 107 (C, 1, D
irect Orange 107 ---Sumilite Splat Orange GD Extra Conc) C, 1, Direct Red 79 (C, 1, Direct Red 79 ---Sumilite Splat Red 4BL 170χ) C.I.
Direct Blue 1 (C, 1, Direct Blue 71---Sumilite Blue BRR Conch) Sea Eye Direct Blue 8 (C, 1, Direct Blue 78---Sumilite Subra Blue G Conch) Sea I Direct Red 2 (C, 1, Direct Red 2 --- Benzo Barbuniline 4B) C.I. Direct Red 81 (C, 1Dtrect Red 81 --- Sumilite Red 4B) Violet 51 (C, 1,
Direct Violet 51---Sumilight・
Violet BB) C.I. Direct Orange 26 (C, 1, Di
rect Orange 26 --- Direct First Orange S) C.I. Direct Red 247 (C, 1, Direct Red 247 ---
Japanol Firth Red FA) C.I.
Direct Blue 168 (C, 1, Direct B
lue 168 --- Direct Copper Blue 2B) C.I. Direct Green 85 (Jin 1
．． Direct Green 85 --- Direct Dark Green BA) C.I. Direct
Brown 223 (C, 1, Direct Brown
223---Direct Brown MA) C.I. Direct Brown 106 (C, 1, D
irect Brown 106---Sumilite Splat Brown G Conch) C.I.Direct.
Yellow 142 (C, 1, Direct Yellow
142 ---Sumilight Yellow GR) C,1,Direct Blue 1 ---Direct Sky Blue 6B) The polymer film used in the present invention is made of polyvinyl alcohol and its derivatives, These are modified with olefins such as ethylene and propylene, crotonic acid, acrylic acid, methacrylic acid, maleic acid, etc.
(vinyl acetate resin), saponified EVA resin, nylon resin, polyester resin, etc. are used.

Among these, films made of polyvinyl alcohol and its derivatives are particularly useful polymer films for the present invention because dyes are easily adsorbed and oriented.

In the present invention, as a method for adsorbing and orienting organic direct dyes such as the above-mentioned nickel, zinc, or iron-containing disazo direct dyes on a polymer film, the nickel, zinc, or iron-containing disazo direct dyes are adsorbed and oriented in water. Generally, a method of dissolving an organic direct dye such as a dye and dyeing the polymer film can be adopted. At that time, the concentration of Glauber's salt in the staining solution was reduced to 2%.
Preferable dyeing properties can be obtained by increasing the dyeing temperature to 5°C to 70°C. Orientation of the dichroic dye adsorbed onto the polymer film is achieved by stretching the film before or after adsorption. As a method for stretching a film made of polyvinyl alcohol or a derivative thereof, any method such as a wet method or a dry compression stretching method may be used.

After adsorbing and orienting the organic direct dyes such as nickel, zinc, or iron-containing disazo direct dyes on the polymer film, it is even more effective to perform post-treatment such as boric acid treatment as necessary. be. Boric acid treatment improves the light transmittance and degree of polarization of the polarizing film. The conditions for boric acid treatment include the type of polymer film used, nickel or zinc,
Or, it varies depending on the type of stepped direct dye such as iron-containing disazo direct dye, but generally the boric acid concentration is 1 to 1.
15%, preferably 5-10%, and the treatment temperature is 3
It is desirable that the temperature be in the range of 0 to 80°C, preferably 50 to 75°C. If the boric acid concentration is 1% or less and the temperature is 30°C or less, the treatment effect will be small;
% or higher or the temperature is higher than ac'c, the polarizing film becomes brittle and undesirable. Furthermore, if necessary, fixing treatment may be performed in combination with an aqueous solution containing a cationic polymer compound.

The dye-based polarizing film thus obtained is used as a polarizing plate by laminating a protective film with excellent optical transparency and mechanical strength on one or both sides thereof.

Materials for forming the protective film include conventionally used cellulose acetate films and acrylic films, as well as fluorinated films such as 47-fluorinated ethylene-hexafluorinated propylene-based copolymers, polyester resins, and polyolefin resins. Alternatively, a film made of polyamide resin that is uniaxially stretched and oriented may be used.
It will be done.

〔Effect of the invention〕

The dye-based polarizing film obtained in this way not only exhibits high durability for a long time even at high temperatures compared to conventional dye-based polarizing films, but also has high durability comparable to that of polarizing films using iodine. Because of its polarization performance, it is suitable for various liquid crystal displays, especially for automotive applications that require high polarization performance and durability, and for display applications in industrial instruments used in various environments.

[Example] The present invention will be explained in more detail with reference to Examples below, but these are merely illustrative and the present invention is not limited thereto.

Note that the light transmittance in the present invention refers to the light transmittance of one polarizing film. Measuring device: Hitachi UV-330
type spectrophotometer), JXSZ8701 (XYZ color system,
and,X,,Y,,Z,.

The degree of polarization is the value of Y determined according to the color display method (color display method using a color system), and the degree of polarization is the value of Y determined by measuring the light transmittance with two polarizing films stacked on top of each other, determining the value of Y using the method described above, and then It was calculated using the formula.

Here, Y II is determined from the light transmittance (called parallel transmittance) measured when two samples are stacked so that the polarizing films are aligned in the same direction. Y is the value of Y, and Y is the light transmittance (
This is the value of Y determined from the cross transmittance. The polarization performance is the value at a specific absorption wavelength for Examples 1 to 4 and Comparative Example I, and the value at a specific absorption wavelength for Examples 5 to 7 and Comparative Examples 2 to 3.
It is displayed as an average value at 400 to 700 nm.

Moreover, the durability in the present invention is expressed by 8E0 shown below. In other words, ΔE0 is used to measure the light transmittance of the polarizing film.Meter: Otsuka Electronics MCPD-100 spectrophotometer), L
The values of m, am, b* are determined according to JIS-Z・8729 (L
The object color is displayed using the "a"b" color system and the L*u*v0 color system), and is a value obtained from the following formula.

(ΔE") i, j = (((ΔL")i, j)" + ((Δa"
)i, j)”+((Δb11) i, j)2
)l/2.

However, ΔL")i, j=(L")i-(L")j(Δa
”)i,j-(a”)i-(a”)j(Δb”
) i, j = (b") i - (b") ji = Mini durability test = If this value exceeds 1 after the durability test, the discoloration will be noticeable compared to the initial one, and from the viewpoint of quality stability That's a problem.

Example 1 A polyvinyl alcohol film (Kuraray Vinylon [F] #7500) having a thickness of 75 μm was stretched 4 times along the vertical axis to obtain a polarizing film base material. While keeping this polyvinyl alcohol film under tension, a nickel-containing disazo direct dye represented by formula (n) was added to a concentration of 0.15 wt%, and a dyeing aid, Glauber's Salt, was added to a concentration of 2.0 wt%60. °
It was immersed in an aqueous solution of C for 10 minutes. In addition, 7.5 boric acid
After being immersed in an aqueous solution at 65°C with a concentration of wL% for 10 minutes, it was washed with water at 20°C for 30 seconds to obtain a polarizing film. Table 1 shows the polarization characteristics of this polarizing film and the value of ΔE when left in a 100°C dry thermostat for 500 hours.
Shown below.

Example 2 By the same method as in Example 1, a polyvinyl alcohol film was prepared using a zinc-containing disazo direct dye represented by formula (n) at a concentration of 0.150 wt% and a sodium sulfate concentration of 2.0 wt%60. It was immersed in an aqueous solution at °C for 12 minutes and treated with boric acid to obtain a polarizing film.

Table 1 shows the polarization characteristics of this polarizing film and the value of ΔE1 when the film was left in a 100°C dry constant temperature bath for 500 hours.

Example 3 By the same method as in Example 1, a polyvinyl alcohol film was prepared by the formula (II). It was immersed in an aqueous solution of C for 15 minutes and treated with boric acid to obtain a polarizing film. The polarization properties of this polarizing film and 1
Table 1 shows the value of ΔE0 when the sample was left in a dry constant temperature bath at 00°C for 500 hours.

Comparative Example 1 A polyvinyl alcohol film was coated with 0 of the disazo direct dye represented by the following formula (■) by the same method as in Example 1.
．． 05 wt%, 1.0% of Glauber's salt. 6 with a concentration of OWL%
It was immersed in an aqueous solution at 0° C. for 8 minutes and treated with boric acid to obtain a polarizing film. The polarization characteristics of this polarizing film and 100°
ΔE0 when left in C-Dry thermostat for 500 hours
The values of are shown in Table 1.

Example 4 By the same method as in Example 1, a polyvinyl alcohol film was prepared at 60°C at a concentration of 0.15 wt% of the nickel-containing disazo direct dye shown in 2 (■) and 3 Owt% of Glauber's salt. Aqueous solution: immersed for 13 minutes at night and treated with boric acid to obtain a polarizing film.

Table 1 shows the polarization characteristics of this polarizing film and the value of ΔE″- when it was left in a 100°C dry constant temperature bath for 500 hours.

Example 5 A polyvinyl alcohol film was prepared in the same manner as in Example 1 using 0.2 wt% of a nickel-containing disazo direct dye represented by the formula (■) and C.I. Direct Red 2 (C, 1, Direct Red). 2) to 0,02
wt%, C.I. Direct Yellow 12
(C, 1, Direct Yellow 12) to O,
OO6wt%, C.I. Direct Blue 202
(C, 1, Direct Blue 202) to 0.0
It was immersed for 6 minutes in an aqueous solution of 5 wt % and anhydrous sodium sulfate at 60° C. at a concentration of 2.0 wt %, and then treated with boric acid to obtain a dye-based polarizing film exhibiting a neutral color. Table 1 shows the polarization characteristics of this polarizing film.

Example 6 A polyvinyl alcohol film was prepared in the same manner as in Example 1 using 0.06 wt% of the zinc-containing disazo direct dye represented by formula (II) and C.I. Direct Red 2 (C,1, Direct Red). 2) to 0.0
5 wt%, C.I. Direct Yeo-1
2 (C, 1, Direct Yellow 12) to O
, OO6 wt%, C,1, Direct Violet 9 (C,1, Direct Violet 9) at 0.03 wt%, and anhydrous Glauber's salt at 2.0 wt
% in an aqueous solution at 60° C. for 6 minutes and then treated with boric acid to obtain a dye-based polarizing film exhibiting a neutral color. Table 1 shows the polarization characteristics of this polarizing film.

Example 7 A polyvinyl alcohol film was coated with 0.07 wt% of iron-containing disazo direct dye represented by formula (II) and C.I. Direct Red 2 (C, 1, Direct) in the same manner as in Example 1. Red 2) 0, 04
5 wt%, C.I. Direct Yellow 12
(C, 1, Direct Yellow 12) to O
,OO6wt%,C,1,Direct Violet 9 (C,1,Direct Violet
9) 0. 0 3 wt% and anhydrous mirabilite at a concentration of 2.0 wt% at 60°C.
The film was immersed in an aqueous solution of for 5 minutes and treated with boric acid to obtain a dye-based polarizing film exhibiting a neutral color. Table 1 shows the polarization characteristics of this polarizing film.
Shown below.

Comparative Example 2 A polyvinyl alcohol film was coated with C.I. Direct Black 17 (C,
1, Direct Black 1? ) to 0.01w
t%, and anhydrous mirabilite at a concentration of 1.0 w t%6
A neutral color polarizing film was obtained by immersing it in an aqueous solution at 0° C. for 10 minutes and performing boric acid treatment, but the polarizing performance was inferior to that of the polarizing film of the present invention.

Table 1 shows the polarization characteristics of this polarizing film.

Comparative Example 3 A polyvinyl alcohol film was coated with C.I. Direct Yellow 12 (C
, T, Dtrect Yellow 12 ) to 0, 0
04 wt%, C.I. Direct Blank 1
7 (C, 1, Direct Black 1?) at 0.01 wt%, C.I. Direct Blue 1 (C
91, Direct Blue 1) O, OO8w
t%, and anhydrous mirabilite at 1. It was immersed in an aqueous solution at 60°C with a concentration of Qwt% for 8 minutes and treated with boric acid to obtain a neutral color polarizing film, but the polarizing performance was inferior to the polarizing film of the present invention. there were. Table 1 shows the polarization characteristics of this polarizing film.
Shown below.

Table 1

Claims (2)

[Claims] (1) In a dye-based polarizing film formed by adsorbing and orienting a dichroic dye on a polymer film, the dichroic dye has the general formula (
I) (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, Me is a transition metal atom, and nickel (Ni)
), or zinc (Zn), or iron (Fe). R_1
and R_2 is bonded to an azo group at a position adjacent to the hydroxyl group that is complex bonded to the transition metal, and further has a substituent group such as a sulfonic acid group, a sulfonamide group, an amino group, an acylamino group, an allyl amino group, or an azo group. Indicates a 1-naphthol or 2-naphthol residue that can have non-adjacent hydroxyl groups. Therefore, formula (I) has 1 to 3 sulfonic acid groups. ) water-soluble nickel or zinc,
Or a dye-based polarizing film characterized by being an iron-containing disazo direct dye. (2) In a dye-based polarizing film formed by adsorbing and orienting a dichroic dye on a polymer film, the dichroic dye has the general formula (
I) (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, Me is a transition metal atom, and nickel (Ni)
), or zinc (Zn), or iron (Fe). R_1
and R_2 is bonded to an azo group at a position adjacent to the hydroxyl group that is complex bonded to the transition metal, and further has a substituent group such as a sulfonic acid group, a sulfonamide group, an amino group, an acylamino group, an allyl amino group, or an azo group. Indicates a 1-naphthol or 2-naphthol residue that can have non-adjacent hydroxyl groups. Therefore, formula (I) has 1 to 3 sulfonic acid groups. ) water-soluble nickel or zinc,
Or a dye-based polarizing film exhibiting a neutral color, characterized by using at least one type of iron-containing disazo-based direct dye in combination with an organic-based direct dye that absorbs in a specific wavelength region. (3) Claim 1 or 2, wherein the polymer film is a film made of polyvinyl alcohol or a derivative thereof.
Dye-based polarizing film as described in .