Sulfonyloxy substituted tris-azoaryl dyes and copper complex salts thereof and polarizing films dyed therewith

Dyes having the specific structural formula (1) set out below, their copper salt dyes, water-soluble azo dyes containing the dyes or the copper salt dyes, and polarizing films containing the water-soluble azo dyes: ##STR1## wherein A means a benzene or naphthalene ring having a sulfone group or a base thereof, Y and Z individually denote a group of the following formula (a); ##STR2## wherein R.sup.2 is a hydrogen atom, a methyl group, a methoxyl group or an ethoxyl group and R.sup.3 is a methyl, methoxyl or ethoxyl group, R.sup.1 represents an amino, C.sub.1-4 alkylamino, C.sub.2-4 alkylcarboxyamino, benzoylamino or phenylamino group bonded to the 6 or 7 position of the naphthalene ring, and X denotes a hydrogen, sodium, potassium or lithium atom, with the proviso that Y and Z are different but, when both R.sup.2 s are hydrogen atoms and both R.sup.3 s are methoxyl groups, Y and Z may be the same.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to novel azo dyes and copper complex salts thereof, 
to water-soluble dye compositions containing them and to polarizing films 
containing an azo dye or copper complex salt dye of this invention 
adsorbed and oriented thereon as dichroic dyestuff and having high 
durability and a high polarization degree. 
2. Description of the Related Art 
It is now the common practice to produce a polarizing film by stretching a 
film of polyvinyl alcohol (PVA) or a derivative thereof or of a polyene 
and then causing iodine or a dichroic dye to be adsorbed as a polarizing 
element on the resulting oriented film. 
Among such polarizing films, those making use of iodine as a polarizing 
element are excellent in initial polarizing performance but have poor 
resistance to water or heat. They are hence accompanied by a problem in 
durability when employed over a long period of time under high temperature 
and humidity conditions. To improve their durability, it is contemplated, 
for example, to enhance their treatment in an aqueous solution containing 
formaldehyde or boric acid or to use, as a protective film, a polymer film 
having low moisture permeability. Their durability is however still 
insufficient under high temperature and moisture conditions. 
Polarizing films making use of a dichroic dye as a polarizing element have 
better durability against water and heat compared with polarizing films 
using iodine but are inferior in polarizing ability compared to the 
latter. With a view toward improving this drawback, polarizing films using 
an organic dye as a polarizing element with improved heat resistance and 
polarizing ability are proposed in Japanese Patent Laid-Open No. 
313568/1989 [Chem. Absts. 112(24): 218407r] and Japanese Patent Laid-Open 
No. 12606/1991 [Chem. Absts. 115(4): 38339y]. When employed as polarizing 
films, such organic dyes are generally used in combination with a dye 
having absorption in a particular wavelength range to provide the 
polarizing films with a neutral color. It is therefore the current 
situation that depending on the dyes employed, such polarizing films may 
undergo a substantial color change at high temperatures. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a dye-base polarizing 
film, and specifically to provide a high-quality polarizing film capable 
of exhibiting polarizing ability comparable with iodine-base polarizing 
films and, even when two or more dyes are used in combination to provide a 
neutral color, having excellent polarizing ability and heat resistance. 
Another object of the present invention is to provide a novel azo dye for 
achieving the above object. 
The present inventors have conducted extensive research with a view toward 
obtaining a polarizing film which uses a dye as a polarizing element and 
is excellent in polarizing ability and heat resistance, resulting in the 
completion of the present invention. 
The present invention therefore provides: 
1) an azo dye represented by the following formula (1): 
##STR3## 
wherein A means a benzene or naphthalene ring having a sulfone group or a 
base thereof, Y and Z individually denote a group of the following formula 
(a): 
##STR4## 
wherein R.sup.2 is a hydrogen atom, a methyl group, a methoxyl group or an 
ethoxyl group and R.sup.3 is a methyl, methoxyl or ethoxyl group, R.sup.1 
represents an amino, C.sub.1-4 alkylamino, C.sub.2-4 alkylcarboxyamino, 
benzoylamino or phenylamino group bonded to the 6 or 7 position of the 
naphthalene ring, and X denotes a hydrogen, sodium, potassium or lithium 
atom, with the proviso that Y and Z are different but, when both R.sup.2 s 
are hydrogen atoms and both R.sup.3 s are methoxyl groups, Y and Z may be 
the same; 
2) a copper complex salt dye represented by the following formula (7): 
##STR5## 
wherein A, X, Y and R.sup.1 have the same meanings as defined above in the 
formula (1), and Z.sup.2 is represented by the following formula (b): 
##STR6## 
wherein R.sup.2 has the same meaning as defined above in the formula (a); 
3) the water-soluble composition comprising the azo dye of the formula (1) 
or a copper complex salt dye of the formula (7); and 
4) a polarizing film dyed with a water-soluble dye of this invention. 
The polarizing film dyed using the water-soluble dye according to this 
invention has high heat resistance and high polarization degree and is 
therefore a polarizing film having excellent optical properties. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As the azo dyes of the present invention represented by the formula (1), 
those represented by the following formulas (2) to (6) are particularly 
preferred: 
##STR7## 
wherein A, X, R.sup.1, R.sup.2 and R.sup.3 have the same meanings as 
defined in the formula (1), and R.sup.4 represents an amino, methylamino, 
ethylamino, acetylamino, benzoylamino or phenylamino group bonded to the 6 
or 7 position of the naphthalene ring. 
As the copper complex salt dyes represented by the formula (7), those 
represented by the following formulas (8) to (11) are especially 
preferred: 
##STR8## 
wherein A, X, R.sup.1 R.sup.2 and R.sup.3 have the same meanings as 
defined in the formula (1), and R.sup.4 represents an amino, methylamino, 
ethylamino, acetylamino, benzoylamino or phenylamino group bonded to the 6 
or 7 position of the naphthalene ring. 
The azo dyes of this invention represented by the formulas (1) to (6) can 
be prepared using a known diazotization process and coupling process like 
conventional azo dyes. 
For example, an amino compound represented by the following formula (12): 
EQU A--NH.sub.2 ( 12) 
wherein A has the same meaning as defined above is diazotized, followed by 
the coupling with a compound represented by the following formula (13) 
EQU Y'--NH.sub.2 ( 13) 
wherein Y' means a group represented by the following formula (a'): 
##STR9## 
wherein R.sup.2 and R.sup.3 have the same meanings as defined above. 
After the compound so obtained is diazotized again, the diazotized compound 
is coupled with a compound represented by the following formula (14): 
EQU Z'--NH.sub.2 ( 14) 
wherein Z' means a group represented by the formula (a') with the proviso 
that the combination of R.sup.2 and R.sup.3 may become the same as Y' only 
when R.sup.2 is a hydrogen atom and R.sup.3 is a methoxyl group, whereby a 
disazo compound represented by the following formula (15) is produced: 
EQU A--N.dbd.N--Y--N.dbd.N--Z--NH.sub.2 ( 15) 
wherein A, Y and Z have the same meanings as defined above. In the 
production processes of these intermediates, each diazotization can be 
carried out in a conventional manner wherein a nitrite such as sodium 
nitrite is mixed with an aqueous solution or suspension of the amine in a 
mineral acid such as hydrochloric acid or sulfuric acid or alternatively 
by a reverse process in which a nitrite is first added to a neutral to 
slightly alkaline, aqueous solution of the amine and the resulting mixture 
is mixed with a mineral acid. The diazotization temperature may suitably 
range from -10.degree. C. to 40.degree. C. 
The coupling can be conducted by simply mixing an acidic aqueous solution 
of the amine in hydrochloric acid or acetic acid with the above-described 
dis-azo solution and then adjusting the pH of the resultant mixture to 
3-7. The coupling temperature may suitably range from -10.degree. C. to 
40.degree. C. 
The disazo compound so formed can then be subjected to the next 
diazotization step either as is, namely, in the form of a solution or 
suspension or after causing it to precipitate by acidification or salting 
out and then collecting same by filtration. 
The azo dyes represented by the formulas (1) to (6) can then be obtained by 
diazotizing the disazo compound of the formula (15) and then coupling the 
resultant compound with a compound represented by the following formula 
(16): 
##STR10## 
wherein R.sup.1 and X have the same meanings as defined above. 
The diazotization of the above dis-azo compound may be conducted in a 
conventional manner as in the above diazotization process but a reverse 
process is preferred when the dis-azo compound has very low solubility 
under an acidic condition. The diazotization temperature may suitably 
range from 0.degree. C. to 40.degree. C. The resulting reaction mixture is 
in the form of a suspension. This suspension can be used in the next 
coupling step either as is or after obtaining a presscake of the diazonium 
salt by filtration. 
To conduct the coupling, the suspension or presscake of the diazonium salt 
is added in portions to an aqueous alkaline solution of the coupling 
component. Here, an alkali is added as needed to maintain the pH of the 
reaction mixture at 8 to 11. Usable preferred examples of the alkali 
include carbonates such as sodium, potassium and lithium carbonates, 
ammonia and amines such as mono-, di- or triethanolamine. In addition, the 
hydroxide or bicarbonate of sodium, potassium or the like can also be used 
in combination. Further, a usual coupling promoter such as pyridine or 
urea can also be added. The coupling temperature may suitably range from 
-10.degree. C. to 40.degree. C. 
After the completion of the coupling, sodium chloride and/or potassium 
chloride is added as needed to achieve salting out, whereby a target azo 
dye of one of the formulas (1) to (6) are collected. 
To obtain the copper complex salts of the water-soluble dyes, said salts 
being represented by the formula (7) to (11), a conventional process can 
be followed. Namely, a water-soluble dye of one of the formulas (1) to (5) 
is heated normally to 70.degree.-100.degree. C. together with a copper 
salt such as copper sulfate, copper chloride or copper acetate in an 
aqueous solution. At this time, ammonia, or an organic amine such as 
monoethanolamine, diethanolamine, monopropanolamine or pyridine can be 
added as needed. 
Specific examples of the compound of the formula (12) as the raw material 
include sulfanilic acid, metanilic acid, aniline-2,4-disulfonic acid, 
aniline-2,5-disulfonic acid, 2-naphthylamine-6-sulfonic acid, 
2-naphthylamine-4,8-disulfonic acid, 2-naphthylamine-3,6-disulfonic acid, 
2-naphthylamine-5,7-disulfonic acid, 2-naphthylamine-6,8-disulfonic acid, 
and the like. 
Specific examples of the compounds represented by the formula (13) or (14) 
include p-cresidine, 2,5-dimethoxyaniline, 2,5-diethoxyaniline, 
o-toluidine, p-xylidine, o-anisidine and the like. 
Specific examples of the compound represented by the formula (16) include J 
acid (2-amino-5-naphthol-7-sulfonic acid), .gamma.acid 
(2-amino-8-naphthol-6-sulfonic acid), N-methyl J acid, N-ethyl J acid, 
N-propyl J acid, N-butyl J acid, N-methyl .gamma.acid, N-ethyl 
.gamma.acid, N-propyl .gamma.acid, N-butyl .gamma.acid, N-acetyl J acid, 
N-propionyl J acid, N-butyryl J acid, N-acetyl .gamma.acid, N-propionyl 
.gamma.acid, N-butyryl .gamma.acid, N-benzoyl J acid, N-benzoyl 
.gamma.acid, N-phenyl J acid and N-phenyl .gamma.acid, and the sodium, 
potassium and lithium salts thereof. 
As the polymer film employed to produce the polarizing film of this 
invention, a hydrophilic polymer film is preferred. Specific examples of 
its material include polymers such as polyvinyl alcohol, polyvinyl formal, 
polyvinyl acetal and polyvinyl butyral; those obtained by modifying them 
with ethylene, propylene, acrylic acid, maleic acid, acrylamide or the 
like; and cellulose resins. These polymers are particularly useful in that 
they have high solubility in water or a hydrophilic organic solvent, good 
compatibility with the dyes of the present invention, excellent 
film-forming property and, when stretch-oriented subsequent to formation 
into films, and dyeing facilitate orientation of the dyes of the present 
invention. 
As a process for producing the polarizing film of this invention using an 
above-described polymer and a dye of this invention, the polymer is formed 
into a film, followed by dyeing; or the dye of the present invention is 
added to a solution of the polymer to dye the polymer solution, followed 
by the formation of the dyed polymer solution into a film. 
The above dyeing, film formation and stretching can be conducted generally 
in the following manner. 
A polymer film is immersed at 20.degree.-80.degree. C., preferably 
30.degree.-50.degree. C. for 1-60 minutes, preferably 3-20 minutes in a 
dye bath containing a dye according to this invention and, if necessary, 
inorganic salts such as sodium chloride and sodium sulfate, and dyeing 
assistants such as surface-active agents, the concentration of said dye 
being 0.1-5 wt. %, preferably 0.8-2.5 wt. % based on the polymer film to 
be dyed, so that the polymer is dyed. The polymer film so dyed is treated 
with boric acid as needed, and is then dried. 
As an alternative, the polymer is dissolved in water and/or a hydrophilic 
organic solvent such as an alcohol, glycerin or dimethylformamide, to 
which a dye according to the present invention is added to dye the polymer 
solution. The dyed polymer solution is formed into a film by solution 
casting, solution coating, extrusion or the like, whereby a dyed film is 
produced. 
The concentration of the polymer dissolved in the solvent varies depending 
on the type of the polymer but may be 5-30 wt. %, preferably 10-20 wt. %. 
The concentration of the dye according to the present invention dissolved 
in the solvent also varies depending on the type of the polymer, the type 
of the dye, the thickness of the resulting film, properties required upon 
employment as a polarizing film, and the like but may generally be 0.1-5 
wt. % with about 0.8-2.5 wt. % being preferred. 
The unstretched film obtained by dyeing or film formation as described 
above is stretched in a uniaxially by a suitable method. By this 
stretching, dye molecules are oriented to develop polarizing ability. 
Uniaxial stretching methods include wet draw stretching, dry draw 
stretching, dry inter-roll compression stretching, etc. The stretching can 
be conducted by any of such methods. Although it is preferred to conduct 
this stretching at a draw ratio in a range of from 2 times to 9 times, a 
range of from 2.5 times to 6 times is preferred when polyvinyl alcohol or 
a derivative thereof is used. 
After the stretching and orientation, boric acid treatment is applied in 
order to improve the water-proofness and polarizing ability of the 
stretched film, By this boric acid treatment, both the light transmittance 
and the polarity of the film are improved. Regarding the conditions for 
the boric acid treatment, the boric acid concentration is generally 1-15 
wt. %, preferably 3-10 wt. % and the treatment temperature may desirably 
be in the range of 30.degree.-80.degree. C., preferably 
40.degree.-80.degree. C. The treatment cannot bring about sufficient 
effects when the concentration of boric acid is lower than 1 wt. % or the 
temperature is lower than 30.degree. C. When the concentration of boric 
acid is higher than 15 wt. % or the temperature exceeds 80.degree. C., the 
resulting polarizing film will be brittle. Boric acid concentrations and 
treatment temperatures outside their respective ranges described above are 
therefore not preferred. 
The azo dyes represented by the formulas (1) to (6) and their copper 
complex salt dyes represented by the formulas (7) to (11) can be used 
either singly or in combination. Moreover, combinations of one or more 
other dyes with the dyes of the present invention make it possible to 
produce polarizing films dyed in various hues. When such other dyes are 
combined, any dyes can be used as such other dyes as long as they have 
characteristic absorption in a wavelength range different from those of 
the dyes of the present invention and are provided with a high degree of 
dichroism. The followings are examples of particularly preferred dyes as 
expressed in terms of color index (C.I.) generic names: 
C.I. Direct Yellow 12, C.I. Direct Red 2, 
C.I. Direct Yellow 44, C.I. Direct Red 79, 
C.I. Direct Yellow 28, C.I. Direct Red 81, 
C.I. Direct Yellow 142, C.I. Direct Red 247, 
C.I. Direct Violet 9, C.I. Direct Blue 1, 
C.I. Direct Violet 51, C.I. Direct Blue 71 C.I. Direct Blue 78, 
C.I. Direct Orange 26, C.I. Direct Blue 168, 
C.I. Direct Orange 39, C.I. Direct Blue 202, 
C.I. Direct Orange 107, 
C.I. Direct Brown 106, C.I. Direct Green 85, 
C.I. Direct Brown 223. 
When water-soluble dyes or their copper complex salt dyes represented by 
the formulas (1) to (11) are employed as components for neutral colors 
which are used particularly widely, polarizing films capable of exhibiting 
superb polarizing properties and preferred absorption characteristics can 
be obtained. Moreover, their moisture resistance are excellent. 
The polarizing films produced as described above can be used by applying 
various processing thereto. For example, they can be formed as films or 
sheets and can be used as they are. Depending on application purposes, 
they can be laminated with a polymer such as a triacetate, acrylic or 
urethane polymer to form protective layers thereon. Further, transparent 
conductive films of indium-tin oxides or the like can be formed for actual 
applications on the surfaces of the polarizing films by a vacuum 
depositing, sputtering or coating process. 
The present invention will hereinafter be described by specific examples. 
It is to be noted that these examples are merely illustrative and are not 
intended to limit the present invention thereto. 
The term "polarization degree" as used herein is a value measured by the 
following method. Namely, two polarizing films were placed in the optical 
path of a spectrophotometer with their stretched directions extending in 
parallel with each other. Based on the light transmittance (T//) so 
measured at the maximum absorption wavelength in the visible range and the 
light transmittance (TI) at the same wavelength as measured by superposing 
the two polarizing films with their stretched directions extending at a 
right angle, the polarization degree (V) was calculated using the 
following formula: 
##EQU1## 
Further, the durability in the present invention is expressed by .DELTA.E* 
which is to be defined below. Namely, the light transmittance of a 
polarizing film was measured. Its L*, a* and b* values were calculated in 
accordance with the method prescribed in the Japanese Industrial Standard 
(JIS), Z8729 (Method for Specification of Non-Luminous Objects by the 
L*,a*,b* color system and the L*,u*,v* color system). .DELTA.E* is a value 
obtained in accordance with the following formula: 
##EQU2## 
where, (.DELTA.L*).sub.i,j =(L*).sub.i -(L*)*j 
EQU (.DELTA.a*).sub.i,j =(a*).sub.i -(a*)*j 
EQU (.DELTA.b*).sub.i,j =(b*).sub.i -(b*)*j 
EQU i: before durability test 
EQU j: after durability test 
.DELTA.E* values greater than 1 indicate a noticeable color change compared 
with the color in the initial stage and hence pose a problem from the 
standpoint of stability in quality. 
Incidentally, all designations of "part" or "parts" in the examples 
indicate part or parts by weight.

EXAMPLE 1 
Sodium 2,5-dimethyl-4-aminoazobenzene-4'-sulfonate (32.7 parts; 0.1 mole) 
was dissolved in 330 parts of water, followed by the addition of 31 parts 
of concentrated hydrochloric acid and 6.9 parts of sodium nitrite for 
diazotization. After a solution of 13.7 parts of p-cresidine in an aqueous 
solution of hydrochloric acid was added to the reaction mixture, sodium 
acetate was added to neutralize the resultant mixture to pH 4 so that 
coupling was effected. After the completion of the reaction, the reaction 
mixture was filtered whereby a presscake containing 44.3 parts of a 
dis-azo compound represented by the following formula was obtained. 
##STR11## 
The presscake was dissolved in 2000 parts of warm water with neutralizing 
by sodium hydroxide, followed by the addition of 31 parts of concentrated 
hydrochloric acid and 6.9 parts of sodium nitrite for diazotization. After 
the completion of the diazotization, excess nitrite was decomposed by the 
addition of sulfamic acid, and the resulting suspension of the diazonium 
salt was then added dropwise at about 20.degree. C. to a solution of 31.5 
parts of N-phenyl J acid in a 10% aqueous solution of sodium carbonate so 
that coupling was effected. Subsequent to stirring for 2 hours, sodium 
chloride was added in a great excess to induce salting out. After the 
reaction mixture was stirred overnight, it was filtered, washed with a 3% 
aqueous solution of sodium chloride and then dried, whereby 73 parts of a 
tris-azo dye represented by the following formula (17) were obtained. 
##STR12## 
______________________________________ 
Elemental analysis data: 
C H N S 
______________________________________ 
Calculated (%) 55.40 3.79 11.90 
7.78 
Found (%) 55.20 3.71 12.05 
7.85 
______________________________________ 
The dye of the formula (17) was formulated into a 0.3 g/l dye bath. The dye 
bath was maintained at 42.degree. C., in which a polyvinyl alcohol film of 
75 .mu.m in thickness was immersed to dye it for 2 minutes. The film so 
dyed, which was still in a wet state, was stretched fivefold at 43.degree. 
C. in a 3% aqueous solution of boric acid. In the stretched state, the film 
was rinsed with water and dried so that a polarizing film having a bluish 
purple color was produced. The polarization degree V of the polarizing 
film at its maximum absorption wavelength .lambda..sub.max was measured. 
As a result, the single-plate transmittance, .lambda..sub.max and V were 
found to be 43%, 575 nm and 99.0%, respectively. 
A dye composition, which had been prepared by proportioning the dye of the 
formula (17), C.I. Direct Yellow 12, C.I. Direct Orange 39, C.I. Direct 
Red 81 and C.I. Direct Blue 202 at a ratio of 7:1:2:3:10, was formulated 
into a 0.2 g/l dye bath. The dye bath was maintained at 42.degree. C., in 
which a polyvinyl alcohol film of 75 .mu.m in thickness was immersed to 
dye it for 4 minutes. The film so dyed, which was still in a wet state, 
was stretched 5 times at 43.degree. C. in a 3% aqueous solution of boric 
acid. In the stretched state, the film was rinsed with water and dried so 
that a polarizing film having a neutral color was produced. The 
polarization degree of the polarizing film at 40% single-plate 
transmittance was 98.5%. 
.DELTA.E* of the polarizing film of the neutral color was 0.7 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room. 
EXAMPLE 2 
In a similar manner to Example 1 except that 25.3 parts of N-methyl J acid 
were used instead of 31.5 parts of N-phenyl J acid, a tris-azo dye 
represented by the following formula (18) was obtained. 
##STR13## 
______________________________________ 
Elemental analysis data: 
C H N S 
______________________________________ 
Calculated (%) 52.03 3.84 12.87 
8.42 
Found (%) 52.00 3.71 12.62 
8.33 
______________________________________ 
A polyvinyl alcohol film was treated in an aqueous solution of the dye of 
the formula (18) in a similar manner to Example 1, so that a polarizing 
film was produced. The film so obtained had a bluish purple color. The 
polarization degree V Of the polarizing film at its maximum absorption 
wavelength .lambda..sub.max was measured. As a result, the single-plate 
transmittance, .lambda..sub.max and V were found to be 43%, 575 nm and 
97.5%, respectively. 
In a similar manner to Example 1 except that the dye of the formula (18) 
was used instead of the dye of the formula (17), a polarizing film having 
a neutral color was produced. The polarization degree of the polarizing 
film at 40% single-plate transmittance was 98.0%. 
.DELTA.E* of the polarizing film of the neutral color was 0.8 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room. 
EXAMPLE 3 
2-Amino-4,8-naphthalenesulfonic acid (30.3 parts; 0.1 mole) was dissolved 
in 600 parts of water, followed by the addition of 31 parts of 
concentrated hydrochloric acid and 6.9 parts of sodium nitrite for 
diazotization. After the completion of the reaction, excess nitrite was 
decomposed by the addition of sulfamic acid, to which a solution of 12.2 
parts of p-xylidine in an aqueous solution of hydrochloric acid was added. 
Then, sodium acetate was added at 15.degree.-20.degree. C. to neutralize 
the resultant mixture to pH 4 so that coupling was effected. After the 
completion of the reaction, precipitated crystals were collected by 
filtration, whereby 42.5 parts of a mono-azo compound represented by the 
following formula was obtained. 
##STR14## 
The mono-azo compound so obtained was neutralized with sodium hydroxide and 
dissolved in 500 parts of water, followed by the addition of 31 parts of 
concentrated hydrochloric acid and 6.9 parts of sodium nitrite for 
diazotization. After the completion of the diazotization, excess nitrite 
was decomposed by the addition of sulfamic acid. After a solution of 13.7 
parts of p-cresidine in an aqueous solution of hydrochloric acid was added 
to the reaction mixture, sodium acetate was added at 15.degree.-20.degree. 
C. to neutralize the resultant mixture to pH 4 so that coupling was 
effected. After the completion of the reaction, the precipitated crystals 
were collected by filtration, whereby 56.1 parts of a dis-azo compound 
represented by the following formula were obtained. 
##STR15## 
The dis-azo compound so obtained was thereafter neutralized with sodium 
hydroxide and dissolved in 2000 parts of wan water, followed by the 
addition of 31 parts of concentrated hydrochloric acid and 6.9 parts of 
sodium nitrite for diazotization. After the completion of the 
diazotization, excess nitrite was decomposed by the addition of sulfamic 
acid, and the resulting suspension of the diazonium salt was then added 
dropwise at about 20.degree. C. to a solution of 31.5 parts of N-phenyl. J 
acid in a 10% aqueous solution of sodium carbonate so that coupling was 
effected. Subsequent to stirring for 2 hours, sodium chloride was added in 
a great excess to induce salting out. After the reaction mixture was 
stirred overnight, the reaction product was collected by filtration, 
washed with a 3% aqueous solution of sodium chloride and then dried, 
whereby 77 parts of a tris-azo dye represented by the following formula 
(19) were obtained. 
##STR16## 
______________________________________ 
Elemental analysis data: 
C H N S 
______________________________________ 
Calculated (%) 51.69 3.30 10.05 
9.86 
Found (%) 51.50 3.41 10.22 
9.77 
______________________________________ 
A polyvinyl alcohol film was treated in an aqueous solution of the dye of 
the formula (19) in a similar manner to Example 1, so that a polarizing 
film was produced. The film so obtained had a bluish purple color. The 
polarization degree V of the polarizing film at its maximum absorption 
wavelength .lambda..sub.max was measured. As a result, the single-plate 
transmittance, .lambda..sub.max and V were found to be 43%, 585 nm and 
99%, respectively. 
In a similar manner to Example 1 except that the dye of the formula (19) 
was used instead of the dye of the formula (17), a polarizing film having 
a neutral color was produced. The polarization degree of the polarizing 
film at 40% single-plate transmittance was 98.5%. 
.DELTA.E* of the polarizing film of the neutral color was 0.7 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room. 
EXAMPLES 4-62 
In a similar manner to Examples 1-3, dyes of the formula (1) shown in Table 
1 were obtained. In the table, each hue, .lambda..sub.max and polarization 
degree are those observed or measured upon production of a polarizing film 
by the single use of the corresponding dye, while each .DELTA.E* is a value 
upon production of a polarizing film of a neutral color by the use of the 
corresponding dye instead of the dye of the formula (17) in Example 1. 
3 TABLE 1 
Y Z Single-plate Polarization Ex. A R.sup.2 R.sup.3 R.sup.2 R.sup.3 
R.sup.1 Hue .lambda..sub.max (nm) transmittance (%) degree (%) .DELTA. 
E* 
4 
##STR17## 
CH.sub.3 CH.sub.3 CH.sub.3 OCH.sub.3 
##STR18## 
Reddish purple 555 43 98.5 0.8 
5 " H OCH.sub.3 " " 
##STR19## 
Bluish purple 580 " 99.0 0.7 6 " " " " " 6-NHCH.sub.3 " 580 " 97.5 
0.8 
7 " " " " " 
##STR20## 
Reddish purple 560 " 98.5 0.9 
8 
##STR21## 
" " " " 
##STR22## 
Blue 585 " 99.0 0.9 
9 
##STR23## 
OCH.sub.3 " " " " Bluish purple 580 " 99.0 0.8 
10 
##STR24## 
OCH.sub.3 OCH.sub.3 CH.sub.3 OCH.sub.3 6-NHCH.sub.3 Bluish purple 580 
43 97.5 0.9 
11 " " " " " 
##STR25## 
Reddish purple 560 " 98.5 0.7 
12 
##STR26## 
" " " " 
##STR27## 
Blue 585 " 99.0 0.8 
13 
##STR28## 
H " H " " Bluish purple 585 " 99.0 0.7 14 " " " " " 6-NHCH.sub.3 " 
585 " 97.5 0.8 
15 " " " " " 
##STR29## 
Reddish purple 565 " 98.5 0.8 
16 
##STR30## 
H OCH.sub.3 H OCH.sub.3 
##STR31## 
Blue 590 43 99.0 0.9 17 " CH.sub.3 " CH.sub.3 CH.sub.3 " Bluish 
purple 585 " 99.0 0.9 
18 
##STR32## 
" CH.sub.3 " OCH.sub.3 6-NH.sub.2 Bluish purple 570 " 98.5 0.7 19 
##STR33## 
" " " " 7-NHCH.sub.3 Blue 585 " 99.0 0.7 
20 
##STR34## 
CH.sub.3 " " " 
##STR35## 
Blue 575 " 99.0 0.8 
21 
##STR36## 
" " " " 7-NH.sub.2 Bluish purple 590 " 97.5 0.8 
22 
##STR37## 
CH.sub.3 CH.sub.3 CH.sub.3 OCH.sub.3 6-NHCOCH.sub.3 Reddish purple 560 
43 98.5 0.9 
23 
##STR38## 
" " " " 
##STR39## 
Blue 595 " 99.0 0.9 
24 
##STR40## 
" " " " 6-NHCH.sub.3 Blue 585 " 99.0 0.8 
25 
##STR41## 
" " " " 
##STR42## 
Blue 590 " 97.5 0.9 
26 
##STR43## 
" " " " 7-NHCOCH.sub.3 Bluish purple 565 " 98.5 0.7 
27 
##STR44## 
" " " " 6-NHC.sub.2 H.sub.5 Blue 575 " 99.0 0.8 
28 
##STR45## 
H OCH.sub.3 CH.sub.3 OCH.sub.3 6-NH.sub.2 Bluish purple 575 43 99.0 0.8 
29 
##STR46## 
" " " " 7-NHCH.sub.3 Blue 590 " 98.5 0.6 
30 
##STR47## 
" " " " 
##STR48## 
Blue 580 " 99.0 0.7 
31 
##STR49## 
" " " " 7-NH.sub.2 Bluish purple 595 " 99.0 0.9 
32 
##STR50## 
" " " " 6-NHCOCH.sub.3 Reddish purple 565 " 97.5 0.8 
33 
##STR51## 
" " " " 
##STR52## 
Blue 600 " 98.5 0.9 
34 
##STR53## 
H OCH.sub.3 CH.sub.3 OCH.sub.3 6-NHCH.sub.3 Blue 590 43 99.0 0.8 35 
##STR54## 
" " " " 
##STR55## 
Blue 595 " 99.0 0.7 
36 
##STR56## 
" " " " 7-NHCOCH.sub.3 Bluish purple 570 " 97.5 0.9 
37 
##STR57## 
" " " " 7-NHC.sub.2 H.sub.5 Blue 580 " 98.5 0.7 
38 
##STR58## 
OCH.sub.3 " " " 6-NH.sub.2 Bluish purple 575 " 99.0 0.8 
39 
##STR59## 
" " " " 7-NHCH.sub.3 Blue 590 " 99.0 0.9 
40 
##STR60## 
OCH.sub.3 OCH.sub.3 CH.sub.3 OCH.sub.3 
##STR61## 
Blue 580 43 98.5 0.8 
41 
##STR62## 
" " " " 7-NH.sub.2 Bluish purple 595 " 99.0 0.7 
42 
##STR63## 
" " " " 6-NHCOCH.sub.3 Reddish purple 565 " 99.0 0.9 
43 
##STR64## 
" " " " 
##STR65## 
Blue 600 " 97.5 0.8 
44 
##STR66## 
" " " " 
##STR67## 
Blue 595 " 98.5 0.7 
45 
##STR68## 
" " " " 
##STR69## 
Bluish purple 570 " 99.0 0.8 
46 
##STR70## 
OCH.sub.3 OCH.sub.3 CH.sub.3 OCH.sub.3 6-NHC.sub.2 H.sub.5 Blue 580 43 
99.0 0.9 
47 
##STR71## 
CH.sub.3 " H " 6-NH.sub.2 Blue 575 " 97.5 0.8 
48 
##STR72## 
" " " " 7-NHCH.sub.3 Blue 590 " 98.5 0.9 
49 
##STR73## 
" CH.sub.3 " " 
##STR74## 
Blue 580 " 99.0 0.8 
50 
##STR75## 
" " " " 7-NH.sub.2 Bluish purple 595 " 99.0 0.8 
51 
##STR76## 
OCH.sub.3 OCH.sub.3 " " 7-NHCOCH.sub.3 Reddish purple 565 " 98.5 0.9 
52 
##STR77## 
OCH.sub.3 OCH.sub.3 H OCH.sub.3 
##STR78## 
Blue 600 43 99.0 0.9 
53 
##STR79## 
H " " " 6-NHCH.sub.3 Blue 590 " 99.0 0.7 
54 
##STR80## 
" " " " 
##STR81## 
Blue 595 " 97.5 0.9 
55 
##STR82## 
OC.sub.2 H.sub.5 OC.sub.2 H.sub.5 " " 7-NHCOCH.sub.3 Bluish purple 570 
" 98.5 0.8 
56 
##STR83## 
" " " " 6-NHC.sub.2 H.sub.5 Blue 580 " 99.0 0.9 
57 
##STR84## 
CH.sub.3 CH.sub.3 " " 
##STR85## 
Blue 580 " 99.0 0.8 
58 
##STR86## 
CH.sub.3 CH.sub.3 H OCH.sub.3 
##STR87## 
Blue 585 43 97.5 0.8 
59 
##STR88## 
" OCH.sub.3 " " 
##STR89## 
Blue 580 " 98.5 0.8 
60 
##STR90## 
" " " " 
##STR91## 
Blue 585 " 99.0 0.9 
61 
##STR92## 
OCH.sub.3 " " " 
##STR93## 
Blue 580 " 99.0 0.9 
62 
##STR94## 
" " " " 
##STR95## 
Blue 585 " 98.5 0.7 
EXAMPLE 63 
Ten parts of the dye of the formula (17) described in Example 1 were 
dissolved in 100 parts of water. After 12 parts of monoethanolamine were 
added, an aqueous solution of 2.6 parts of crystalline copper sulfate was 
added, followed by heating at 90.degree. C. for 3 hours. Sodium chloride 
was added and the resultant mixture was cooled, whereby the reaction 
product was salted out. After the reaction mixture was stirred overnight, 
the reaction product was collected by filtration, washed with a 5% aqueous 
solution of sodium chloride and then dried, so that 9 parts of a copper 
complex salt dye represented by the following formula (20) were obtained. 
##STR96## 
______________________________________ 
Elemental analysis data: 
C H N S 
______________________________________ 
Calculated (%) 51.00 3.12 11.25 
7.36 
Found (%) 51.12 3.07 11.23 
7.28 
______________________________________ 
A polyvinyl alcohol film was treated in an aqueous solution of the dye of 
the formula (20) in a similar manner to Example 1, so that a polarizing 
film was produced. The film so obtained had a bluish purple color. The 
polarization degree V of the polarizing film at its maximum absorption 
wavelength .lambda..sub.max was measured. As a result, the single-plate 
transmittance, .lambda..sub.max and V were found to be 43%, 605 nm and 
98%, respectively. 
In a similar manner to Example 1 except that the dye of the formula (20) 
was used instead of the dye of the formula (17) employed in Example 1, a 
polarizing film having a neutral color was produced. The polarization 
degree of the polarizing film at 40% single-plate transmittance was 98%. 
.DELTA.E* of the polarizing film of the neutral color was 0.9 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room. 
EXAMPLE 64 
Ten parts of the tris-azo dye of the formula (19) described in Example 3 
were dissolved in 100 parts of water, followed by the addition of 14 parts 
of monoethanolamine and then 2.8 parts of copper sulfate. The mixture so 
obtained was heated to conduct a complexing reaction at 
90.degree.-95.degree. C. After the completion of the reaction, sodium 
chloride was added so that the reaction product was salted out. The 
reaction product was collected by filtration and then dried, whereby 9.5 
parts of a copper complex salt dye represented by the following formula 
(21) were obtained. 
##STR97## 
______________________________________ 
Elemental analysis data: 
C H N S 
______________________________________ 
Calculated (%) 48.12 2.76 9.58 9.40 
Found (%) 48.01 2.61 9.42 9.35 
______________________________________ 
A polyvinyl alcohol film was treated in an aqueous solution of the dye of 
the formula (21) in a similar manner to Example 1, so that a polarizing 
film was produced. The film so obtained had a bluish purple color. The 
polarization degree V of the polarizing film at its maximum absorption 
wavelength .lambda..sub.max was measured. As a result, the single-plate 
transmittance, .lambda..sub.max and V were found to be 43%, 615 nm and 
98%, respectively. 
In a similar manner to Example 1 except that the dye of the formula (21) 
was used instead of the dye of the formula (17) employed in Example 1, a 
polarizing film having a neutral color was produced. The polarization 
degree of the polarizing film at 40% single-plate transmittance was 98%. 
.DELTA.E* of the polarizing film of the neutral color was 0.9 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room. 
EXAMPLES 65-102 
In a similar manner to Examples 63 and 64, the copper complex salt dyes 
shown in Table 2 were prepare using the dyes of the formula (1) as raw 
materials. In the table, each hue, .lambda..sub.max and polarization 
degree are those observed or measured upon production of a polarizing film 
by the single use of the corresponding dye, while each .DELTA.E* is a value 
upon production of a polarizing film of a neutral color by the use of the 
corresponding dye instead of the dye of the formula (17) in Example 1. 
TABLE 2 
__________________________________________________________________________ 
Single-plate 
Polariza- 
Example number of trans- tion 
Example 
raw material 
Hue .lambda. max 
mittance (%) 
degree (%) 
.DELTA. E* 
__________________________________________________________________________ 
65 5 Blue 610 43 98.0 0.9 
66 8 Greenish blue 
615 " 98.0 0.8 
67 9 Blue 610 " 98.0 0.8 
68 12 Greenish blue 
615 " 98.0 0.9 
69 13 Blue 615 " 98.0 0.9 
70 16 Greenish blue 
620 " 98.0 0.7 
71 2 " 605 " 97.5 0.9 
72 4 " 585 " 98.5 0.8 
73 18 " 600 " 99.0 0.9 
74 19 " 615 " 99.0 0.8 
75 20 " 605 " 97.5 0.8 
76 21 " 620 " 98.0 0.9 
77 23 Greenish blue 
625 43 98.0 0.8 
78 27 " 605 " 98.0 0.8 
79 6 " 610 " 98.0 0.9 
80 7 " 590 " 98.0 0.9 
81 28 " 605 " 98.5 0.7 
82 29 " 620 " 98.0 0.9 
83 30 " 610 " 98.5 0.8 
84 31 " 625 " 98.0 0.8 
85 33 " 630 " 98.0 0.9 
86 37 " 610 " 98.5 0.8 
87 10 " 610 " 98.0 0.9 
88 11 " 590 " 98.0 0.8 
89 38 " 605 " 98.0 0.8 
90 39 Greenish blue 
620 43 98.0 0.9 
91 40 " 610 " 98.0 0.9 
92 41 " 625 " 98.0 0.7 
93 43 " 630 " 97.5 0.9 
94 46 " 610 " 98.5 0.8 
95 14 " 615 " 99.0 0.9 
96 15 " 595 " 99.0 0.8 
97 47 " 610 " 97.5 0.8 
98 48 " 625 " 98.0 0.9 
99 49 " 615 " 98.0 0.8 
100 50 " 630 " 98.0 0.8 
101 52 " 635 " 98.0 0.9 
102 56 " 615 " 98.0 0.9 
__________________________________________________________________________ 
COMATIVE EXAMPLE 1 
In a similar manner to Example 1 except that the dye synthesized in Example 
1 was replaced by the dye disclosed in Example 1 of Japanese Patent 
Laid-Open No. 313568/1989 and represented by the following structural 
formula (A): 
##STR98## 
a polarizing film was produced. The polarization degree of the polarizing 
film at its 580 nm maximum absorption wavelength and 43% single-plate 
transmittance was 96%, which was inferior to those of the polarizing films 
obtained using the dyes of the present invention. 
In a similar manner to Example 1, a polarizing film having a neutral color 
was also produced. The polarization degree of the polarizing film at 40% 
single-plate transmittance was 97%. 
.DELTA.E* of the polarizing film of the neutral color was 2.1 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room, which was inferior to those of the neutral-color polarizing films 
obtained using the dyes of the present invention as measured in the 
heat-resistance tests, respectively. 
COMATIVE EXAMPLE 2 
In a similar manner to Example 1 except that the dye synthesized in Example 
1 was replaced by the dye disclosed in Example 3 of Japanese Patent 
Laid-Open No. 12606/1991 and represented by the following structural 
formula (B): 
##STR99## 
a polarizing film was produced. The polarization degree of the polarizing 
film at its 600 nm maximum absorption wavelength and 43% single-plate 
transmittance was 97%, which was inferior to those of the polarizing films 
obtained using the dyes of the present invention. 
Similarly to Example 1, a polarizing film having a neutral color was also 
produced. The polarization degree of the polarizing film at 40% 
single-plate transmittance was 96.5%. 
.DELTA.E* of the polarizing film of the neutral color was 2.5 after it had 
been left over for 500 hours in a 100.degree. C.-dry constant-temperature 
room, which was inferior to those of the neutral-color polarizing films 
obtained using the dyes of the present invention as measured in the 
heat-resistance tests, respectively.