U.S. patent application number 11/454929 was filed with the patent office on 2006-10-19 for dye compositions for anisotropic dye films, anisotropic dye films and polarizing elements.
This patent application is currently assigned to MITSUBISHI CHEMICAL CORPORATION. Invention is credited to Ryuichi Hasegawa, Masami Kadowaki, Junichi Oizumi, Hideo Sano, Tomio Yoneyama.
Application Number | 20060230551 11/454929 |
Document ID | / |
Family ID | 34799324 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060230551 |
Kind Code |
A1 |
Hasegawa; Ryuichi ; et
al. |
October 19, 2006 |
Dye compositions for anisotropic dye films, anisotropic dye films
and polarizing elements
Abstract
To provide a dye composition for an anisotropic dye film,
capable of forming an anisotropic dye film which has good heat
resistance, has little defects and shows high dichroism; an
anisotropic dye film formed by using such a composition for an
anisotropic dye film; and a polarizing element employing such an
anisotropic dye film.
Inventors: |
Hasegawa; Ryuichi;
(Yokohama-shi, JP) ; Oizumi; Junichi;
(Yokohama-shi, JP) ; Kadowaki; Masami;
(Yokohama-shi, JP) ; Yoneyama; Tomio;
(Yokohama-shi, JP) ; Sano; Hideo; (Yokohama-shi,
JP) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
MITSUBISHI CHEMICAL
CORPORATION
Tokyo
JP
|
Family ID: |
34799324 |
Appl. No.: |
11/454929 |
Filed: |
June 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP05/00808 |
Jan 18, 2005 |
|
|
|
11454929 |
Jun 19, 2006 |
|
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Current U.S.
Class: |
8/534 |
Current CPC
Class: |
G02B 5/305 20130101 |
Class at
Publication: |
008/534 |
International
Class: |
D06P 3/82 20060101
D06P003/82 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 19, 2004 |
JP |
2004-010283 |
May 19, 2004 |
JP |
2004-149375 |
Dec 27, 2004 |
JP |
2004-376442 |
Claims
1. A dye composition for an anisotropic dye film, which comprises a
dye and a compound having at least two groups selected from the
group consisting of an acidic group, a basic group and a neutral
group, wherein at least one of said at least two groups is a basic
group.
2. The dye composition for an anisotropic dye film according to
claim 1, wherein the content of the compound to the dye is at least
0.05 and at most 4 by molar ratio.
3. The dye composition for an anisotropic dye film according to
claim 1, wherein the compound is a cyclic compound.
4. The dye composition for an anisotropic dye film according to
claim 1, wherein the compound is a hydroxylamine.
5. The dye composition for an anisotropic dye film according to
claim 1, wherein the compound is an amino acid.
6. The dye composition for an anisotropic dye film according to
claim 1, wherein the composition is a solution which further
contains a solvent.
7. The dye composition for an anisotropic dye film according to
claim 1, wherein the dye is an acidic dye.
8. The dye composition for an anisotropic dye film according to
claim 1, wherein the dye is an azo dye.
9. An anisotropic dye film formed by using the dye composition for
an anisotropic dye film as defined in claim 1.
10. The anisotropic dye film according to claim 9, formed by a wet
system deposition method.
11. The anisotropic dye film according to claim 9, wherein the film
thickness is at most 30 .mu.m.
12. An anisotropic dye film comprising a dye and a compound having
at least two groups selected from the group consisting of an acidic
group, a basic group and a neutral group, wherein at least one of
said at least two groups is a basic group.
13. The anisotropic dye film according to claim 9, which has a
dichroic ratio of at least 5.
14. The anisotropic dye film according to claim 12, which has a
dichroic ratio of at least 5.
15. The anisotropic dye film according to claim 9, wherein the
order parameter before a heat resistance test at 170.degree. C. for
30 minutes, is at least 0.5, and the decrease in the order
parameter after the heat resistance test is at most 7%.
16. The anisotropic dye film according to claim 12, wherein the
order parameter before a heat resistance test at 170.degree. C. for
30 minutes, is at least 0.5, and the decrease in the order
parameter after the heat resistance test is at most 7%.
17. A polarizing element employing the anisotropic dye film as
defined in claim 9.
18. A polarizing element employing the anisotropic dye film as
defined in claim 12.
Description
TECHNICAL FIELD
[0001] The present invention relates to dye compositions for
anisotropic dye films capable of forming anisotropic dye films
showing high dichroism, which are useful for e.g. polarizing plates
provided on display devices such as light control devices, liquid
crystal devices (LCD) or organic electroluminescence devices
(OLED), anisotropic dye films formed by using such dye compositions
for anisotropic dye films, and polarizing elements employing such
anisotropic dye films.
BACKGROUND ART
[0002] In LCD, linear polarizers or circular polarizers are used to
control optical rotation or birefringence in display. Also in OLED,
circular polarizers are used to prevent reflection of outside
light. Heretofore, for such polarizers (polarizing elements),
iodine has been widely used as a dichroic material. However, iodine
is highly sublimable and thus has had a drawback that when it is
used for a polarizing film, its heat resistance or light fastness
is inadequate.
[0003] Therefore, as disclosed in e.g. patent document 1 or
non-patent documents 1 and 2, an anisotropic dye film as a
polarizing film has been studied wherein an organic dye is used as
a dichroic material. However, conventional organic dye films have
had a problem such that only dye films or polarizing elements are
obtainable which are substantially inferior in dichroism as
compared with ones employing iodine.
[0004] Patent Document 1: U.S. Pat. No. 2,400,877
[0005] Non-Patent Document 1: Dreyer, J. F., Phys. And Colloid
Chem., 1948, 52, 808., "The Fixing of Molecular Orientation"
[0006] Non-Patent Document 2: Dreyer, J. F., Journal de Physique,
1969, 4, 114., "Light Polarization From Films of Lyotropic Nematic
Liquid Crystals"
DISCLOSURE OF THE INVENTION
[0007] It is an object of the present invention to provide a dye
composition for an anisotropic dye film capable of forming an
anisotropic dye film which has good heat resistance, has little
defects and shows high dichroism, an anisotropic dye film formed by
using such a dye composition for an anisotropic dye film, and a
polarizing elements employing such an anisotropic dye film.
[0008] The present inventors have conducted an extensive study to
solve the above-mentioned problems and as a result, have found it
possible to provide an anisotropic dye film which has good heat
resistance, has little defects and shows high dichroism, by using a
dye composition for an anisotropic dye film which contains a
compound (hereinafter referred to as "the compound of the present
invention") having at least two groups selected from the group
consisting of an acidic group, a basic group and a neutral group,
wherein at least one of said at least two groups is a basic group.
Thus, the present invention has been accomplished.
[0009] The present invention provides the following: [0010] (1) A
dye composition for an anisotropic dye film, which comprises a dye
and a compound having at least two groups selected from the group
consisting of an acidic group, a basic group and a neutral group,
wherein at least one of said at least two groups is a basic group.
[0011] (2) The dye composition for an anisotropic dye film
according to (1), wherein the content of the compound to the dye is
at least 0.05 and at most 4 by molar ratio. [0012] (3) The dye
composition for an anisotropic dye film according to (1) or (2),
wherein the compound is a cyclic compound. [0013] (4) The dye
composition for an anisotropic dye film according to (1) or (2),
wherein the compound is a hydroxylamine. [0014] (5) The dye
composition for an anisotropic dye film according to (1) or (2),
wherein the compound is an amino acid. [0015] (6) The dye
composition for an anisotropic dye film according to any one of (1)
to (5), wherein the composition is a solution which further
contains a solvent. [0016] (7) The dye composition for an
anisotropic dye film according to any one of (1) to (6), wherein
the dye is an acidic dye. [0017] (8) The dye composition for an
anisotropic dye film according to any one of (1) to (7), wherein
the dye is an azo dye. [0018] (9) An anisotropic dye film formed by
using the dye composition for an anisotropic dye film as defined in
any one of (1) to (8). [0019] (10) The anisotropic dye film
according to (9), formed by a wet system deposition method. [0020]
(11) The anisotropic dye film according to (9) or (10), wherein the
film thickness is at most 30 .mu.m. [0021] (12) An anisotropic dye
film comprising a dye and a compound having at least two groups
selected from the group consisting of an acidic group, a basic
group and a neutral group, wherein at least one of said at least
two groups is a basic group. [0022] (13) The anisotropic dye film
according to any one of (9) to (12), which has a dichroic ratio of
at least 5. [0023] (14) The anisotropic dye film according to any
one of (9) to (12), wherein the order parameter before a heat
resistance test at 170.degree. C. for 30 minutes, is at least 0.5,
and the decrease in the order parameter after the heat resistance
test is at most 7%. [0024] (15) A polarizing element employing the
anisotropic dye film as defined in any one of (9) to (14).
EFFECTS OF THE INVENTION
[0025] According to the present invention, an anisotropic dye film
is provided which has good heat resistance, has little defects and
shows high dichroism, and by such an anisotropic dye film, a
polarizing element is provided which is excellent in heat
resistance and light fastness and which is excellent also in
polarizing performance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is microscopic photographs showing defects in
anisotropic dye films obtained in Examples 1-1 to 1-4 and
Comparative Examples 1-1 to 1-3.
BEST MODE FOR CARRYING OUT THE INVENTION
[0027] Now, the present invention will be described in detail with
reference to practical embodiments, but it should be understood
that the following description of the constituting elements are
merely exemplary (typical examples) of practical embodiments of the
present invention, and the present invention is by no means thereby
restricted.
[0028] The anisotropic dye film in the present invention is a dye
film having anisotropy in an electromagnetic characteristic in
optional two directions selected from a total of three directions
in a three-dimensional coordinate system comprising the thickness
direction of the dye film and mutually perpendicular optional two
in-plane directions. The electromagnetic characteristic may, for
example, be an optical characteristic such as absorption or
refraction, or an electric characteristic such as resistance or
capacitance. As a film having an optical anisotropy in e.g.
absorption or refraction, a linearly polarizing film, a circularly
polarizing film, a phase difference film or an anisotropic
electroconductive film may, for example, be mentioned.
[0029] The anisotropic dye film of the present invention is
preferably employed for a polarizing film, a phase difference film
or an anisotropic electroconductive film. Particularly preferably,
it is employed for a polarizing film.
Dye Composition for Anisotropic Dye Film
[0030] Firstly, the dye composition for an anisotropic dye film of
the present invention will be described.
[0031] The dye composition for an anisotropic dye film of the
present invention is characterized by comprising a dye and a
compound (hereinafter referred to as the compound of the present
invention) having at least two groups selected from the group
consisting of an acidic group, a basic group and a neutral group,
wherein at least one of said at least two groups is a basic
group.
COMPOUND OF THE INVENTION
[0032] The compound of the present invention is a compound having
at least two groups selected from the group consisting of an acidic
group, a basic group and a neutral group, wherein at least one of
said at least two groups is a basic group, i.e. either one of the
following compounds. [0033] (1) A compound having at least two
basic groups. [0034] (2) A compound having at least one basic group
and at least one acidic group. [0035] (3) A compound having at
least one basic group and at least one neutral group. [0036] (4) A
compound having at least one basic group, at least one acidic group
and at least one neutral group.
[0037] The details of the functional mechanism whereby the
dichroism or heat resistance of the anisotropic dye film is
improved by the incorporation of the compound of the present
invention, are not clearly understood, but it is considered as
follows.
[0038] The compound of the present invention has at least one basic
group. Such at least one basic group is considered to have a mutual
action with an acidic group of the dye molecule in the anisotropic
dye film in a case where the dye molecule has such an acidic group.
By such a mutual action, the dye is considered to have the
molecular orientation increased via the compound of the present
invention. And, it is considered that by the increase of the
molecular orientation of the dye, the anisotropic dye film will
have its defects reduced to increase the dichroism.
[0039] Further, in addition to such one basic group having a mutual
action with the dye molecule, the compound of the present invention
further has at least one acidic, basic or neutral group. It is
considered that by such acidic, basic or neutral group, the dye and
the compound of the present invention will form a salt or will be
agglomerated, whereby the dye composition for an anisotropic dye
film will be prevented from becoming unstable.
[0040] Especially when the compound of the present invention having
a basic group is present against a dye molecule having a terminal
acidic group, an acid/base bond will be formed, whereby the dye
molecules will be regularly oriented to provide a function as a
polarizing plate. However, if the bonding frequency of acid/base is
too high, agglomeration may rather takes place, whereby it becomes
difficult to prepare a film. It is considered that in the present
invention, for example, by using a compound containing basic groups
more than acidic groups, bonding of the basic groups with the
terminal acidic groups of the dye molecule will be properly
prevented to provide a proper bonding frequency of acid/base,
whereby it is possible to prepare a film wherein dye molecules are
regularly oriented without being agglomerated.
[0041] Further, deterioration in performance of the anisotropic dye
film by heating is considered to be caused by disturbance of the
molecular orientation of the dye or a change of the molecular
orientation to an undesirable direction when the dye oriented in
the film receives thermal fluctuation by the heating. As mentioned
above, the compound of the present invention serves to provide
intermolecular interactions such as an electrostatic attracting
force, a repulsive force and a hydrogen bond with functional groups
of the dye. Such interactions of attracting and repulsive forces
function simultaneously between the compound and the dye, whereby
agglomeration due to too much bonding with the dye, or phase
separation due to too much repulsion, can be prevented.
[0042] Thus, it is considered that also in the anisotropic dye film
of the present invention, such intermolecular interactions will
work in good balance between the compound of the present invention
and the dye, which serves a role of fixing the molecular
orientation of the dye in the optimum direction. And, it is
considered that by such fixing of the orientation of dye molecules,
the change in orientation of dye molecules by heating can be
suppressed, whereby the heat resistance of the anisotropic dye film
is improved.
[0043] Such a compound of the present invention is usually a
water-soluble compound.
[0044] The basic group, the acidic group and the neutral group,
which the composition of the present invention has, are as follows.
The acidic group and the basic group are functional groups such
that in an aqueous solution having an inert support electrolyte
added in an amount of from 0.1 to 3 mol/dm, the acidic group is a
functional group having a pka of less than 7, and the basic group
is a functional group having a pka of at least 7. Further, the
neutral group is a group having no dissociation constant. Further,
as disclosed in Kagaku Binran Kisohen (Chemical Handbook Basic) II,
p. 331 (compiled by Chemical Society of Japan, published by Maruzen
Co., Ltd.), pka is logarithmic value of the reciprocal of the
dissociation constant ka, i.e. -log ka.
[0045] As the acidic group, which the compound of the present
invention has, a sulfo group, a carboxyl group or a phosphoric
group may, for example, be mentioned.
[0046] As the basic group, an amino group, a sulfonium group, a
pyrrole group, a 3-pyrroline group, a pyrrolidine group, a pyrazole
group, a 2-pyrazoline group, a pyrazolidine group, an imidazole
group, a 1,2,3-triazole group, a 1,2,4-triazole group, a pyridine
group, a pyridazine group, a piperidine group, a pyrazine group, a
piperazine group, a pyrimidine group or a triazine group may, for
example, be mentioned.
[0047] As the neutral group, a hydroxyl group, an amine oxide
group, a sulfoxide group or a phosphine oxide group may, for
example, be mentioned.
[0048] The above groups may further have substituents, so long as
such substituents do not substantially change the properties of the
dye composition for an anisotropic dye film of the present
invention.
[0049] Some or all of acidic groups and basic groups contained in
the compound of the present invention may take salt forms. The salt
form of a basic group may, for example, be a salt of an inorganic
acid such as hydrochloric acid or sulfuric acid, or a salt of an
organic acid such as acetic acid or formic acid. Further, the salt
form of an acidic group may, for example, be a salt of an alkali
metal such as Na, Li or K, an ammonium salt which may be
substituted by an alkyl group or a hydroxyalkyl group, or an
organic amine salt. In the case of these salt forms, their types
may not be restricted to one type, and a plurality of different
types may be present as mixed.
[0050] The molecular weight of the compound of the present
invention is usually at least 60, preferably at least 75, more
preferably at least 100, particularly preferably at least 140, and
preferably at most 300, more preferably at most 250, particularly
preferably at most 200.
[0051] The compound of the present invention is preferably a
compound having a carbon number of at least 1, more preferably at
least 3, particularly preferably at least 6 and preferably at most
15, further preferably at most 12, particularly preferably at most
10.
[0052] In order to effectively obtain the above effects by the
compound of the present invention, the number of basic groups which
the compound of the present invention has, may be at least 1,
preferably at least 2 and at most 5, more preferably at most 4.
Further, in a case where the compound of the present invention has
basic groups only i.e. without having a neutral group or an acidic
group, the number of basic groups is preferably at least 3 and at
most 5, more preferably at most 4.
[0053] When the compound of the present invention has acidic
groups, the number of acidic groups may be at least 1, preferably
at most 4, more preferably at most 3. Further, the relative ratio
of the number of basic groups/the number of acidic groups in the
compound of the present invention, is preferably at least 1.3 and
at most 4.
[0054] When the compound of the present invention has neutral
groups, the number of neutral groups may be at least 1, and the
number is not particularly limited but is usually at most 8,
preferably at most 6.
[0055] Further, in a case where the compound of the present
invention has at least two basic groups, acidic groups or neutral
groups, such at least two groups may be the same groups or
different groups.
[0056] The compound of the present invention may be either a linear
compound or a cyclic compound.
[0057] As the compound of the present invention, amines are
preferred, and particularly preferred are amino acids, betains,
hydroxyamines or cyclic compounds having basic groups.
[0058] The amino acids are classified into a neutral amino acid, an
acidic amino acid and a basic amino acid, from the nature and the
number of acidic groups and basic groups.
[0059] Specific examples of the neutral amino acid include glycine,
alanine, valine, leucine, isoleucine, phenylalanine, tyrosine,
tryptophan, serine, threonine, proline, 4-hydroxyproline, cysteine,
cystine, methionine, asparagine, glutamine, .beta.-alanine,
citrulline, creatine and kynurenine. Among them, particularly
preferred are phenylalanine, aspargine, 4-hydroxyproline and
.beta.-alanine.
[0060] Further, specific examples of the acidic amino acid include
aspartic acid, glutamic acid, etc. Among them, particularly
preferred is aspartic acid and glutamic acid.
[0061] Further, specific examples of the basic amino acid include
lysine, arginine and histidine.
[0062] The molecular weight of the amino acid is usually at least
60, preferably at least 75 and usually at most 300, preferably at
most 250. If the molecular weight of the amino acid is too large,
the molecular size will be large, whereby orientation of dye
molecules is likely to be disturbed. On the other hand, if it is
too small, the effect for fixing the orientation of dye molecules
may not sufficiently be obtained.
[0063] The betains include, for example, a
carboxylalkyltrialkylammonium hydroxide, a carboxyalkylpyridinium
hydroxide, a sulfoalkyltrialkylammonium hydroxide, a
sulfoalkylpyridinium hydroxide, a phosphoalkyltrialkylammonium
hydroxide, a phosphoalkylpyridinium hydroxide, and derivatives of
these compounds. Among them, carboxymethyltrimethylammonium
hydroxide and sulfopropylpyridinium hydroxide are preferred.
[0064] The molecular weight of the betain is usually at least 60,
preferably at least 75 and usually at most 300, preferably at most
250. If the molecular weight of the betain is too large, the
molecular size will be large, whereby the orientation of dye
molecules is likely to be disturbed. On the other hand, if it is
too small, the effect for fixing the orientation of dye molecules
may not sufficiently be obtained.
[0065] The hydroxylamines include, for example, an aminoalkyl
alcohol, a diaminoalkyl alcohol, an aminoalkyldiol and a
diaminoalkyldiol. Among them, aminopropanediol is preferred.
[0066] The molecular weight of the hydroxyamine is usually at least
60, preferably at least 75 and usually at most 300, preferably at
most 250. If the molecular weight of the hydroxyamine is too large,
the molecular size will be large, whereby the orientation of dye
molecules is likely to be disturbed. On the other hand, if it is
too small, the effect for fixing the orientation of dye molecules
may not sufficiently be obtained.
[0067] The cyclic compounds having basic groups, include, for
example, aminopyridine, diaminopyridine, triaminopyridine,
aminopyridazine, diaminopyridazine, triaminopyridazine,
amimopyrimidine, diaminopyrimidine, triaminopyrimidine,
aminopyrazine, diaminopyrazine, triaminopyrazine, aminotriazine,
diaminotriazine and triaminotriazine. Among them,
triaminopyrimidine is preferred.
[0068] The molecular weight of the cyclic compound having basic
groups is usually at least 60, preferably at least 75 and usually
at most 300, preferably at most 250. If the molecular weight of the
cyclic compound having basic groups is too large, the molecular
size will be large, whereby the orientation of dye molecules is
likely to be disturbed. On the other hand, if it is too small, the
effect for fixing the orientation of dye molecules may not
sufficiently be obtained.
[0069] With respect to the compound of the present invention as
described above, one type may be used alone, or compounds of the
same type or compounds of different types may be used in
combination as a mixture of two or more of them. Further, optical
isomers of e.g. an amino acid may be used alone or in combination.
Further, it may contain a salt form compound and a free form
compound, or may contain compounds of different salt forms.
[0070] The blend amount of the above-described compound of the
present invention in the dye composition for an anisotropic dye
film of the present invention is preferably at least 0.05,
particularly preferably at least 0.1 and preferably at most 4,
particularly preferably at most 3 by a molar concentration ratio to
the dye (the molar concentration ratio of the compound of the
present invention to the dye) in order to sufficiently obtain the
effect for improving the heat resistance, etc. and in order not to
hinder the orientation of dye molecules. If the blend amount of the
compound of the present invention is too small, no adequate effect
for improving the heat resistance, etc. will be obtained by the
incorporation of the compound of the present invention. On the
other hand, if it is too large, the compound of the present
invention is likely to precipitate in the anisotropic dye film.
Dye and Other Components
[0071] The dye to be used for the dye composition for an
anisotropic dye film of the present invention is usually one having
an absorption wavelength of from 400 to 700 nm.
[0072] The dye to be used for the dye composition for an
anisotropic dye film of the present invention is preferably a dye
having an acidic group as a functional group with a view to
effectively obtaining the above-described intermolecular
interaction with the compound of the present invention. Such an
acidic group may, for example, be a sulfo group, a carboxyl group
or a phosphoric group, and such a group may further have a
substituent. From the viewpoint of the high solubility and the
strength of the intermolecular interaction with the compound of the
present invention, the acidic group is preferably a sulfo group or
a carboxyl group.
[0073] These acidic groups may be in a free acid form, or some or
all of them may be in a salt form. Or, a dye in a salt form and a
dye in a free acid form may be present as mixed. The salt form may,
for example, be a salt of an alkali metal such as Na, Li or K, an
ammonium salt which may be substituted by an alkyl group or a
hydroxyalkyl group, or an organic amine salt. The organic amine
may, for example, be a C.sub.1-6 lower alkylamine, a
hydroxy-substituted C.sub.1-6 lower alkylamine or a
carboxy-substituted C.sub.1-6 lower alkylamine. These salt forms
may be used alone or in combination as a mixture of a plurality of
them.
[0074] The dye to be used in the present invention is preferably an
azo dye, whereby a distinct effect can be obtained when it is
combined with the compound of the present invention. The number of
azo groups in the azo dye is preferably at least 2 and at most 4,
more preferably 3, from the viewpoint of the chromaticness and the
production efficiency.
[0075] Further, the dye to be used in the present invention is
preferably water-soluble, since it is subjected to the
after-mentioned wet system film-forming method.
[0076] Further, the dye to be used in the present invention has a
molecular weight of usually at least 200, preferably at least 300
and usually at most 1,500, preferably at most 1,200, in a free
state not taking a salt form, from the viewpoint of the production
efficiency of the dye and the polarizing performance.
[0077] Specific examples of such a dye include dyes disclosed in
the above-mentioned patent document 1, non-patent documents 1 and 2
and non-patent document 3 (J. Lydon, "Chromonics" in "Handbook of
Liquid Crystals Vol. 2B: Low Molecular Weight Liquid Crystals II",
D. Demus, J. Goodby, G. W. Gray, H. W. Spiessm V. Vill ed.,
Willey-VCH. P. 981-1007, (1998)) and dyes having structures shown
in the following formulae (I-1) to (I-14) and from (II-1) to
(II-4). However, the dye is not limited to such specific examples.
##STR1## ##STR2## ##STR3##
[0078] These dyes can be produced in accordance with methods per se
well known. For example, the dye represented by the formula (I-1)
can be produced by the following steps (A) to (C).
[0079] (A) From 3-aminobenzenesulfonic acid (metanilic acid) and
2-methoxyaniline (o-anisidine), a monoazo compound is produced via
diazotization and coupling steps in accordance with a common method
(e.g. "New Dye Chemistry" edited by Hosoda Yutaka, published by
Gihodo on Dec. 21, 1973) p. 396-409).
[0080] (B) The obtained disazo compound is likewise diazotized by a
common method, followed by a coupling reaction with 3-methylaniline
(m-toluidine), to obtain a disazo compound.
[0081] (C) The obtained disazo compound is likewise diazotized by a
common method, followed by a coupling reaction with
7-amino-1-naphthol-3,6-disulfonic acid (RR acid) and salting out
with sodium chloride to obtain the desired dye number (I-1).
[0082] In the dye composition for an anisotropic dye film of the
present invention, the above-mentioned dyes may be used alone, but
two or more of them may be used in combination. Further, dyes other
than the above exemplified dyes may also be incorporated to such an
extent not to decrease the orientation. Thus, anisotropic dye films
having various colors can be produced.
[0083] In a case where other dyes are to be blended, examples of
such dyes to be blended include C.I. Direct Yellow 12, C.I. Direct
Yellow 34, C.I. Direct Yellow 86, C.I. Direct Yellow 142, C.I.
Direct Yellow 132, C.I. Acid Yellow 25, C.I. Direct Orange 39, C.I.
Direct Orange 72, C.I. Direct Orange 79, C.I. Acid Orange 28, C.I.
Direct Red 39, C.I. Direct Red 79, C.I. Direct Red 81, C.I. Direct
Red 83, C.I. Direct Red 89, C.I. Acid Red 37, C.I. Direct Violet 9,
C.I. Direct Violet 35, C.I. Direct Violet 48, C.I. Direct Violet
57, C.I. Direct Blue 1, C.I. Direct Blue 67, C.I. Direct Blue 83,
C.I. Direct Blue 90, C.I. Direct Green 42, C.I. Direct Green 51,
and C.I. Direct Green 59.
[0084] In a case where the above dyes to be blended have acidic
groups, such acidic groups may be in a free acid form, or some or
all of the acidic groups may be in a salt form. Further, a dye in a
salt form and a dye in the free acid form may be present as
mixed.
[0085] As mentioned above, the dye having acidic groups to be used
in the present invention, may be used in its free acid form, or
some of acidic groups may take a salt form. Further, a dye in a
salt form and a dye in an acid form may be present as mixed.
Accordingly, when it is obtained in a salt form at the time of its
production, it may be used as it is or may be converted to a
desired salt form. As a method for conversion to a salt form, a
known method may optionally be employed. For example, the following
methods (1) to (4) may be mentioned.
[0086] (1) A method wherein a strong acid such as hydrochloric acid
is added to an aqueous solution of a dye obtained in a salt form,
to let the dye precipitate in the form of a free acid, and then the
acidic groups of the dye are neutralized with an alkali solution
having a desired counter ion (such as a lithium hydroxide aqueous
solution) for conversion to a salt.
[0087] (2) A method wherein a large excess amount of a neutral salt
having a desired counter ion (such as lithium chloride) is added to
an aqueous solution of a dye obtained in a salt form to carry out a
salt exchange in the form of a salted out cake.
[0088] (3) A method wherein an aqueous solution of a dye obtained
in a salt form is treated with a strongly acidic ion exchange resin
to let the dye precipitate in the form of a free acid, and then the
acidic groups of the dye are neutralized with an alkali solution
having a desired counter ion (such as a lithium hydroxide aqueous
solution) for conversion to a salt.
[0089] (4) A method wherein an aqueous solution of a dye obtained
in a salt form is treated with a strongly acid ion exchange resin
preliminarily treated with an alkali solution having a desired
counter ion (such as a lithium hydroxide aqueous solution), to
carry out a salt exchange.
[0090] The dye composition for an anisotropic dye film of the
present invention comprises the above-described compound of the
present invention and the dye, but as the case requires, additives
such as a solvent, a surfactant and a pH-adjusting agent may be
incorporated.
[0091] As the solvent to be used in the present invention, water,
an organic solvent miscible with water or their mixture is
suitable. A specific example of the organic solvent may, for
example, be a single solvent or a mixed solvent of two or more,
selected from alcohols such as methyl alcohol, ethyl alcohol and
isopropyl alcohol, glycols such as ethylene glycol and diethylene
glycol, and cellosolves such as methyl cellosolve and ethyl
cellosolve.
[0092] In a case where the dye composition for an anisotropic dye
film of the present invention is a solution containing such a
solvent, the concentration of the dye in the dye composition for an
anisotropic dye film, is usually preferably at least 0.01 wt %,
particularly preferably at least 0.1 wt % and usually preferably at
most 50 wt %, particularly preferably at most 30 wt %. If the dye
concentration is too low, sufficient dichroism can not be obtained
in the anisotropic dye film, and if it is too high, the dye is
likely to precipitate.
[0093] In a case where the dye composition for an anisotropic dye
film of the present invention is applied in the form of a dye
solution to a substrate by e.g. the after-mentioned wet system film
forming method, an additive such as a surfactant may be added, as
the case requires, in order to improve the coating property or
wettability to the substrate. As such a surfactant, an anionic,
cationic or nonionic surfactant may be used. The concentration is
usually preferably at least 0.05 wt % and at most 0.5 wt %, as the
concentration in the dye composition for an anisotropic dye film
and as an amount sufficient to obtain the desired effect and not to
impair the orientation of the dye molecules.
[0094] Further, for the purpose of e.g. suppressing instability
such as agglomeration or salt-formation of the dye and the compound
of the present invention in the dye composition for an anisotropic
dye film of the present invention, a pH controlling agent such as a
known acid or alkali may be added before or after mixing the
constituting components to carry out the pH control.
[0095] Further, as additives other than the above, known additives
disclosed in "Additive for Coating", edited by J. Bieleman,
Willey-VCH (2000), may be employed.
Anisotropic Dye Film
[0096] Now, the anisotropic dye film formed by using such a dye
composition for an anisotropic dye film of the present invention,
will be described. With the above described dye composition for an
anisotropic dye film of the present invention comprising the
compound of the present invention and the dye, the dye can exhibit
a high level of molecular orientation. Accordingly, the anisotropic
dye film of the present invention formed by using such a dye
composition for an anisotropic dye film of the present invention,
is a useful dye film showing high dichroism.
[0097] The anisotropic dye film of the present invention shows a
high dichroic ratio and is preferably one having a dichroic ratio
of at least 5, more preferably at least 10, particularly preferably
at least 15.
[0098] Further, as mentioned above, in the dye composition for an
anisotropic dye film of the present invention comprising the
compound of the present invention and the dye, an intermolecular
interaction works between the compound of the present invention and
the dye. And, also in the anisotropic dye film formed by using such
a dye composition for an anisotropic dye film, such an
intermolecular interaction will work, whereby the orientation of
dye molecules will be fixed, and disturbance or change in direction
of the orientation during the heating will be suppressed, thus
leading to a useful anisotropic dye film showing high heat
resistance.
[0099] The heat resistance of the anisotropic dye film which is
practically required, is determined depending upon the environment
in which the anisotropic dye film is to be used and the process for
producing a display device or the like wherein the anisotropic dye
film will be provided. In the present invention, as a standard for
comparison of the heat resistance, a decrease of the order
parameter showing the molecular orientation degree by a heat
resistance test is employed. As a specific heat resistance test, a
test condition may, for example, be such that the film is held in
an environment of 170.degree. C. for 30 minutes. As a sufficient
heat resistance performance of an anisotropic dye film, the
decrease of the order parameter under such a condition is
preferably at most 7%, more preferably at most 5%, particularly
preferably at most 4.6%.
[0100] The anisotropic dye film of the present invention preferably
has a high degree of molecular orientation from the practical
viewpoint, and it is preferably one having an order parameter value
of at least 0.5, more preferably at least 0.6, particularly
preferably at least 0.7, before the heat resistance test.
[0101] Such an anisotropic dye film of the present invention is
prepared by a dry system film-forming method or a wet system
film-forming method by using the dye composition for an anisotropic
dye film of the present invention. In the present invention, in a
case where the solution containing the dye is likely to show liquid
crystallizability, it is preferred to use the wet system
film-forming method.
[0102] The dry system film-forming method may, for example, be a
method of stretching a non-stretched film obtained e.g. by a method
wherein a high molecular weight polymer is formed into a film which
is then dyed with the dye composition for an anisotropic dye film
of the present invention, or by a method wherein the dye
composition for an anisotropic dye film of the present invention is
added to the solution of a high molecular weight polymer to dye the
stock solution, followed by film-forming. Such dyeing, film-forming
and stretching can be carried out by the following common
methods.
[0103] Dyeing is carried out by dipping a polymer film in a dye
bath containing the dye composition for an anisotropic dye film of
the present invention and, as the case requires, an inorganic salt
such as sodium chloride or Glauber's salt and a dyeing assistant
such as a surfactant, usually at a temperature of at least
20.degree. C., preferably at least 30.degree. C. and usually at
most 80.degree. C., preferably at most 50.degree. C., usually for
at least 1 minute, preferably at least 3 minutes and usually at
most 60 minutes, preferably at most 20 minutes, then boric acid
treatment is carried out if necessary, followed by drying.
Otherwise, the high molecular weight polymer is dissolved in water
and/or a hydrophilic organic solvent such as an alcohol, glycerol
or dimethylformamide, then the dye composition for an anisotropic
dye film of the present invention, is added to dye the stock
solution, and this dyed stock solution is formed into a film by a
casting method, a solution-coating method or an extrusion method to
obtain a dyed film. The concentration of the high molecular weight
polymer dissolved in the solvent varies depending upon the polymer,
but it is usually at least 5 wt %, preferably at least 10 wt % and
usually at most 30 wt %, preferably at most 20 wt %. Further, the
concentration of the dye to be dissolved in the solvent is usually
at least 0.1 wt %, preferably at least 0.8 wt % and usually at most
5 wt %, preferably at most 2.5 wt %, based on the polymer.
[0104] A non-stretched film obtained by dyeing and film forming as
described above, is stretched in a monoaxial direction by a
suitable method. By such stretching treatment, the dye molecules
will be oriented to produce dichroism. As a method for stretching
in a monoaxial direction, a method of carrying out tensile
stretching by a wet system method, a method of carrying out tensile
stretching by a dry system method or a method of a pinch roll
compression stretching in a dry system method may, for example, be
mentioned, and any method may be employed. The stretching is
carried out usually at a stretching ratio of at least 2 times and
at most 9 times. However, in a case where a polyvinyl alcohol or
its derivative is employed as the high molecular weight polymer,
the stretching ratio is preferably within a range of at least 2.5
times and at most 6 times. After the stretching and orientation
treatment, boric acid treatment is carried out for the purpose of
improving the water resistance and the polarizing degree of the
stretched film. By such boric acid treatment, the light
transmittance and the degree of polarization of the anisotropic dye
film will be improved. The conditions for such boric acid treatment
may vary depending upon the types of the hydrophilic high molecular
weight polymer and the dye to be used. However, usually, the boric
acid concentration is at least 1 wt %, preferably at least 5 wt %
and usually at most 15 wt %, preferably at most 10 wt %. Further,
the treating temperature is preferably within a range of usually at
least 30.degree. C., preferably at least 50.degree. C. and usually
at most 80.degree. C. If the boric acid concentration is less than
1 wt %, or if the treating temperature is less than 30.degree. C.,
the treating effects tend to be small, and if the boric acid
concentration exceeds 15 wt % or if the treating temperature
exceeds 80.degree. C., the anisotropic dye film tends to be
brittle, such being undesirable.
[0105] The thickness of the anisotropic dye film to be obtained by
such a dry system film-forming method is preferably at least 50
.mu.m, particularly preferably at least 80 .mu.m and preferably at
most 200 .mu.m, particularly preferably at most 100 .mu.m.
[0106] On the other hand, as the wet system film-forming method, a
known method may be mentioned such as a method wherein the dye
composition for an anisotropic dye film of the present invention is
formed into a coating solution, which is applied to a various
substrate such as a glass plate and dried to have the dye oriented
and laminated. The coating method may, for example, be a known
method disclosed, for example, in "Coating Engineering" edited by
Yuji Harazaki, published by Kabushiki Kaisha Asakura Shoten on Mar.
20, 1971, p. 253-277, or "Preparation and Application of a Molecule
Adjusting Material" compiled by Kunihiro Ichimura, published by
Kabushiki Kaisha CMC on Mar. 3, 1998, p. 118-149, or a method
wherein it is applied on e.g. a substrate having orientation
treatment preliminarily applied, by e.g. a spin coating method, a
spray coating method, a bar coating method, a roll coating method
or a blade coating method. In such a case, if the dye concentration
in the dye composition for an anisotropic dye film is too low, no
adequate dichroism can be obtained, and if it is too high, the
film-forming tends to be difficult. The dye concentration in the
dye composition for an anisotropic dye film in the wet system
film-forming method is preferably at least 0.1 wt %, particularly
preferably at least 1 wt % and preferably at most 50 wt %,
particularly preferably at most 30 wt %. The temperature at the
time of the coating is preferably at least 0.degree. C. and at most
80.degree. C., and the humidity is preferably at least 10% RH and
at most 80% RH.
[0107] Further, the temperature at the time of drying the coated
film is preferably at least 0.degree. C. and at most 120.degree.
C., and the humidity is at least 10% RH and at most 80% RH.
[0108] In a case where the anisotropic dye film is to be formed on
a substrate by the wet system film-forming method, the anisotropic
dye film is usually preferably at least 50 nm, more preferably at
least 100 nm and preferably at most 30 .mu.m, more preferably at
most 20 .mu.m, still further preferably at most 1 .mu.m as the
thickness after drying.
[0109] Further, as the substrate material to be used for the wet
system film-forming method, glass, or a triacetate, acrylic,
polyester, triacetyl cellulose or urethane type film may, for
example, be mentioned. Further, on the surface of such a substrate,
an orientation treatment layer may be applied by a known method as
disclosed in e.g. "Liquid Crystal Handbook" published by Maruzen
Co., Ltd. on Oct. 30, 2000, p. 226-239, in order to control the
orientation direction of the dichroic dye.
[0110] A protective layer may be provided, as the case requires, on
the anisotropic dye film of a dichroic dye obtained by the dry
system film-forming method or the wet system film-forming method.
Such a protective layer may be formed by lamination of a
transparent polymer film such as a triacetate, acrylic, polyester,
polyimide, ployacetyl cellulose or urethane type film, and then
subjected to practical use.
[0111] Further, in a case where the dye composition for an
anisotropic dye film of the present invention is used for e.g. a
polarizing filter for various display devices such as ECD and OLED,
the anisotropic dye film of the present invention may be formed
directly on e.g. an electrode substrate constituting such a display
device, or a base material having the anisotropic dye film of the
present invention formed thereon, may be used as a constituting
component of such a display device.
[0112] Further, the anisotropic dye film of the present invention
is one which comprises a dye and a compound having at least two
groups selected from the group consisting of an acidic group, a
basic group and a natural group, wherein at least one of said at
least two groups is a basic group. In such an anisotropic dye film,
the compound having at least two groups selected from the group
consisting of an acidic group, a basic group and a neutral group,
wherein at least one of said at least two groups is a basic group,
and the dye, are the same as the compound of the present invention
and the dye, which are contained in the above-mentioned dye
composition for an anisotropic dye film of the present invention.
Namely, even if the anisotropic dye film is not produced as
described above by means of the dye composition for an anisotropic
dye film of the present invention, a film comprising a dye and the
compound of the present invention, will show the effects of the
present invention.
[0113] The anisotropic dye film of the present invention will
function as a polarizing film whereby a linearly polarized light,
circularly polarized light or oval polarized light can be obtained
by utilizing the anisotropy in light absorption and further is
capable of providing functions as various anisotropic films such as
refractive anisotropy and conductivity anisotropy by suitably
selecting the film-forming process and the composition comprising
the substrate and the dye, whereby it can be made various types of
polarizing elements which can be used for various purposes.
Polarizing Element
[0114] The polarizing element of the present invention is one
employing such an anisotropic dye film of the present invention. In
a case where the anisotropic dye film of the present invention is
formed on a substrate to obtain a polarizing element of the present
invention, the formed anisotropic dye film itself may be employed,
or not only the above-mentioned protective layer, but also layers
having various functions such as an adhesive layer and a
reflection-preventing layer, may be laminated, so that it may be
used in the form of a laminate.
EXAMPLES
[0115] Now, the present invention will be described in further
detail with reference to Examples. However, it should be understood
that the present invention is by no means restricted to such
specific Examples.
[0116] In the following, various evaluations of the formed dye
films were carried out as follows.
[0117] (1) Dichroic ratio
[0118] The transmittance of an anisotropic dye film was measured by
a spectrophotometer having an iodine type polarizing element
disposed in an incident optical system, whereupon the dichroic
ratio was calculated by the following formula. Dichroic ratio
(D)=Az/Ay Az=-log (Tz) Ay=-log (Ty)
[0119] Tz: Transmittance of the dye film against polarized light in
the direction of the absorption axis
[0120] Ty: Transmittance of the dye film against polarized light in
the direction of the polarization axis
[0121] (2) Defects
[0122] Using a polarization microscope Nikon Optiphot-POL and using
an objective lens of 100 magnifications and an ocular lens of 10
magnifications, observation was made at an extinction position, and
a photograph was taken by Nikon Coolpix 950. At that time, the
sample was set so that the transverse direction of the photograph
would be the coating direction.
[0123] (3) Order Parameter (S)
[0124] The transmittance of an anisotropic dye film was measured by
a spectrophotometer having an iodine type polarizing element
disposed in the incident optical system ("instant multilight
measuring system MCPD 2000", manufactured by Otsuka Electronics
Co., Ltd., whereupon the order parameter was calculated by the
following formula. Order parameter (S)=(Az-Ay)/(Az+2.times.Ay)
Az=-log (Tz) Ay=-log (Ty)
[0125] Tz: Transmittance of the dye film against polarized light in
the direction of the absorption axis
[0126] Ty: Transmittance of the dye film against polarized light in
the direction of the polarization axis
[0127] (4) Decrease in the Order Parameter After Heating (Unit:
%)
[0128] The decrease was calculated by the following formula.
Decrease in order parameter=(S1-S2).times.100/S1
[0129] S1: Order parameter before heating
[0130] S2: Order parameter after heating
[0131] In the following, "parts" means "parts by weight".
EXAMPLES USING BASIC AMINO ACIDS AS THE COMPOUND OF THE PRESENT
INVENTION
Example 1-1
[0132] 5 Parts of Dye No. (II-1) and 2.5 parts of L-(+)lysine
monohydrochloride (number of basic groups: 2, number of acidic
groups: 1) (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added
to 92.5 parts of water (molar ratio of the dye to L-(+)lysine
monohydrochloride=1:1), stirred and dissolved, followed by
filtration to obtain a dye composition for an anisotropic dye film
of the present invention having a pH of 7. The above dye
composition for an anisotropic dye film was applied by an
applicator having a gap of 10 .mu.m (manufactured by Imoto
Seisakusho) on a glass substrate having a polyimide oriented film
formed on its surface by a spin coating method (75 mm.times.25 mm,
thickness: 1.1 mm, a polyimide oriented film having a polyimide
film thickness of about 800 .ANG. was preliminarily subjected to
rubbing treatment with cloth), followed by drying naturally to
obtain an anisotropic dye film having a thickness of about 0.4
.mu.m.
[0133] A photograph of defects of the obtained anisotropic dye film
is shown in FIG. 1. Further, the maximum absorption wavelength
(.lamda..sub.max) and the dichroic ratio (D) of the obtained
anisotropic dye film are shown in Table 1.
[0134] Defects of the anisotropic dye film obtained by this Example
were sufficiently little, and the film had a high dichroic ratio
(light absorption anisotropy) sufficiently functionable as a
polarizing film.
Example 1-2
[0135] 14 Parts of the above exemplified Dye No. (II-2) and 3.1
parts of L-(+)lysine monohydrochloride (number of basic groups: 2,
number of acidic groups: 1) (manufactured by Tokyo Kasei Kogyo Co.,
Ltd.) were added to 82.9 parts of water (molar ratio of the dye to
L-(+)lysine monohydrochloride=1:1), stirred and dissolved, followed
by filtration to obtain a dye composition for an anisotropic dye
film of the present invention having a pH of 7. This dye
composition for an anisotropic dye film was applied on the same
substrate as in Example 1-1 under the same conditions to obtain an
anisotropic dye film having a thickness of about 0.9 .mu.m.
[0136] A photograph of defects of the obtained anisotropic dye film
is shown in FIG. 1. Further, the maximum absorption wavelength
(.lamda..sub.max) and the dichroic ratio (D) of the obtained
anisotropic dye film are shown in Table 1.
[0137] Defects of the anisotropic dye film obtained in this Example
were sufficiently little, and the film had a high dichroic ratio
(light absorption anisotropy) sufficiently functionable as a
polarizing film.
Example 1-3
[0138] 15 Parts of the above exemplified Dye No. (II-3) and 3.3
parts of L-(+)lysine monohydrochloride (number of basic groups: 2,
number of acidic groups: 1) (manufactured by Tokyo Kasei Kogyo Co.,
Ltd.) were added to 81.7 parts of water (molar ratio of the dye to
L-(+)lysine monohydrochloride=1:1), stirred and dissolved, followed
by filtration to obtain a dye composition for an anisotropic dye
film of the present invention having a pH of 7. This dye
composition for an anisotropic dye film was applied to the same
substrate as in Example 1-1 under the same conditions to obtain an
anisotropic dye film having a thickness of about 0.9 .mu.m.
[0139] A photograph of defects of the obtained anisotropic dye film
is shown in FIG. 1. Further, the maximum absorption wavelength
(.lamda..sub.max) and the dichroic ratio (D) of the obtained
anisotropic dye film are shown in Table 1.
[0140] Defects of the anisotropic dye film obtained in this Example
were sufficiently little, and the film had a high dichroic ratio
(light absorption anisotropy) sufficiently functionable as a
polarizing film.
Example 1-4
[0141] 14 Parts of the above exemplified Dye No. (II-2) and 3.5
parts of L-(+)arginine hydrochloride (number of basic groups: 4,
number of acidic groups: 1) (manufactured by Tokyo Kasei Kogyo Co.,
Ltd.) were added to 82.5 parts of water (molar ratio of the dye to
L-(+)arginine hydrochloride=1:1), stirred and dissolved, followed
by filtration to obtain a dye composition for an anisotropic dye
film of the present invention having a pH of 7. This dye
composition for an anisotropic dye film was applied to the same
substrate as in Example 1-1 under the same conditions to obtain an
anisotropic dye film having a thickness of about 0.9 .mu.m.
[0142] A photograph of defects of the obtained anisotropic dye film
is shown in FIG. 1. Further, the maximum absorption wavelength
(.lamda..sub.max) and the dichroic ratio (D) of the obtained
anisotropic dye film are shown in Table 1.
[0143] Defects of the anisotropic dye film obtained in this Example
were sufficiently little, and the film had a high dichroic ratio
(light absorption anisotropy) sufficiently functionable as a
polarizing film.
Comparative Example 1-1
[0144] A dye composition for a dye film was prepared in the same
manner as in Example 1-1 except that no L-(+)lysine
monohydrochloride was added, and it was applied to the same
substrate under the same conditions to obtain a dye film.
[0145] With respect to the obtained dye film, various tests were
carried out in the same manner as in Example 1-1, the results of
the observation of defects are shown in FIG. 1, and the evaluation
results of the dichroism are shown in Table 1.
[0146] With the dye film obtained in this Comparative Example,
striped defects were distinct as compared with the anisotropic dye
film in Example 1-1, and the dichroic ratio was lower than the one
in Example 1-1.
Comparative Example 1-2
[0147] A dye composition for a dye film was prepared in the same
manner as in Example 1-2 except that no L-(+)lysine
monohydrochloride was added, and it was applied to the same
substrate under the same conditions to obtain a dye film.
[0148] With respect to the obtained dye film, various tests were
carried out in the same manner as in Example 1-1, the results of
the,observation of defects are shown in FIG. 1, and the evaluation
results of the dichroism are shown in Table 1.
[0149] With the dye film obtained in this Comparative Example,
striped defects were more distinct as compared with the anisotropic
dye film in Example 1-2 and 4, and the dichroic ratio was lower
than the one in Example 1-2 and 4.
Comparative Example 1-3
[0150] A dye composition for a dye film was prepared in the same
manner as in Example 1-3 except that no L-(+)lysine
monohydrochloride was added, and it was applied to the same
substrate under the same conditions to obtain a dye film.
[0151] With respect to the obtained dye film, various tests were
carried out in the same manner as in Example 1-1, the results of
the observation of defects are shown in FIG. 1, and the evaluation
results of the dichroism are shown in Table 1.
[0152] With the dye film obtained in this Comparative Example,
striped defects were distinct as compared with the anisotropic dye
film in Example 1-3, and the dichroic ratio was lower than the one
in Example 1-3. TABLE-US-00001 TABLE 1 Evaluation results Maximum
absorption Dye wavelength Dichroic Examples No. Basic amino acid
(nm) ratio Ex. 1-1 (II-1) L-(+)lysine 430 7 monohydrochloride Comp.
Ex. 1-1 Nil 430 4 Ex. 1-2 (II-2) L-(+)lysine 600 35
monohydrochloride Ex. 1-4 L-(+)arginine 600 34 hydrochloride Comp.
Ex. 1-2 Nil 600 23 Ex. 1-3 (II-3) L-(+)lysine 650 17
monohydrochloride Comp. Ex. 1-3 Nil 650 15
EXAMPLES IN WHICH AN ACIDIC AMINO ACID OR A NEUTRAL AMINO ACID WAS
USED AS THE COMPOUND OF THE PRESENT INVENTION
Example 2-1
[0153] 15 Parts of the above exemplified Dye No. (I-3) and 1.5
parts of L-phenylalanine (manufactured by Kanto Kagaku) as a
neutral amino acid were added to 83.5 parts of water (molar ratio
of the dye to the amino acid=1:0.5), stirred and dissolved,
followed by filtration to obtain a dye composition for an
anisotropic dye film of the present invention. The above dye
composition for an anisotropic dye film was applied by No. 2 bar
coater (manufactured by Tester Sangyo Co., Ltd.) on a glass
substrate having a polyimide oriented film formed on its surface by
a spin coating method (75 mm.times.25 mm, thickness: 1.1 mm, a
polyimide oriented film having a polyimide film thickness of about
800 .ANG. was preliminarily subjected to rubbing treatment with
cloth), followed by drying naturally to obtain an anisotropic dye
film having a thickness of about 0.4 .mu.m. As a heat resistance
test, this anisotropic dye film was held in a constant temperature
chamber ("Fine Oven DF-42", manufactured by Yamato Scientific Co.,
Ltd.) heated to 170.degree. C. for 30 minutes, whereby the change
in the order parameter before and after the heating was
examined.
[0154] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0155] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and good heat resistance, whereby the decrease in
the order parameter by heating was low.
Example 2-2
[0156] 15 Parts of the above exemplified Dye No. (I-3) and 0.32
part of .beta.-alanine (manufactured by Tokyo Kasei Kogyo Co.,
Ltd.) as a neutral amino acid were added to 84.68 parts of water
(molar ratio of the dye to the amino acid=1:0.2), stirred and
dissolved, followed by filtration to obtain a dye composition for
an anisotropic dye film of the present invention. In the same
manner as in Example 2-1, this dye composition for an anisotropic
dye film was applied to a substrate, and the obtained anisotropic
dye film was subjected to the heat resistance test.
[0157] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0158] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and a good heat resistance, whereby the decrease in
the order parameter by heating was low.
Example 2-3
[0159] 15 Parts of the above exemplified Dye No. (I-3) and 1.2
parts of 4-hydroxy-L-proline (manufactured by Tokyo Kasei Kogyo
Co., Ltd.) as a neutral amino acid were added to 83.8 parts of
water (molar ratio of the dye to the amino acid=1:0.5), stirred and
dissolved, followed by filtration to obtain a dye composition for
an anisotropic dye film of the present invention. In the same
manner as in Example 2-1, this dye composition for an anisotropic
dye film was applied to a substrate, and the obtained anisotropic
dye film was subjected to a heat resistance test.
[0160] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0161] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and good heat resistance, whereby the decrease in
the order parameter by heating was low.
Example 2-4
[0162] 15 Parts of the above exemplified Dye No. (I-3) and 2.7
parts of L-aspargine monohydrate (manufactured by Wako Pure
Chemical Industries, Ltd.) as a neutral amino acid were added to
82.3 parts of water (molar ratio of the dye to the amino acid=1:1),
stirred and dissolved, followed by filtration to obtain a dye
composition for an anisotropic dye film of the present invention.
In the same manner as in Example 2-1, this dye composition for an
anisotropic dye film was applied to a substrate, and the obtained
anisotropic dye film was subjected to a heat resistance test.
[0163] The order parameter measured before and after the heat
treatment of the obtained anisotropic dye film, and its decrease,
are shown in Table 2.
[0164] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and good heat resistance, whereby the decrease in
the order parameter by heating was low.
Example 2-5
[0165] 15 Parts of the above exemplified Dye No. (I-3) and 2.3
parts of L-asparginic acid (manufactured by Tokyo Kasei Kogyo Co.,
Ltd.) as an acidic amino acid were added to 82.7 parts of water
(molar ratio of the dye to the amino acid=1:1), stirred and
dissolved, followed by filtration to obtain a dye composition for
an anisotropic dye film of the present invention. In the same
manner as in Example 2-1, this dye composition for an anisotropic
dye film was applied to a substrate, and the obtained anisotropic
dye film was subjected to a heat resistance test.
[0166] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0167] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and good heat resistance, whereby the decrease in
the order parameter by heating was low.
Example 2-6
[0168] 15 Parts of the above exemplified Dye No. (I-3) and 2.7
parts of L-glutamic acid (manufactured by Wako Pure Chemical
Industries, Ltd.) as an acidic amino acid were added to 82.3 parts
of water (molar ratio of the dye to the amino acid=1:1), stirred
and dissolved, followed by filtration to obtain a dye composition
for an anisotropic dye film of the present invention. In the same
manner as in Example 2-I, this dye composition for an anisotropic
dye film was applied to a substrate, and the obtained anisotropic
dye film was subjected to a heat resistance test.
[0169] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0170] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and good heat resistance, whereby the decrease in
the order parameter by heating was low.
2-7
[0171] 15 Parts of the above exemplified Dye No. (I-15) and 5 parts
of L-proline (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a
neutral amino acid were added to 80 parts of water (molar ratio of
the dye to the amino acid=1:2.5), stirred and dissolved, followed
by filtration to obtain a dye composition for an anisotropic dye
film of the present invention. In the same manner as in Example
2-1, this dye composition for an anisotropic dye film was applied
to a substrate, and the obtained anisotropic dye film was subjected
to a heat resistance test.
[0172] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0173] As is evident from Table 2, the anisotropic dye film
obtained in this Example was an anisotropic dye film having a high
order parameter and good heat resistance, whereby the decrease in
the order parameter by heating was low.
Comparative Example 2-1
[0174] 15 Parts of the above exemplified Dye No. (I-3) was added to
85 parts of water, stirred and dissolved, followed by filtration to
obtain a dye composition for an anisotropic dye film. In the same
manner as in Example 2-1, this dye composition for an anisotropic
dye film was applied to a substrate, and the obtained anisotropic
dye film was subjected to a heat resistance test.
[0175] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0176] As is evident from Table 2, the obtained anisotropic dye
film was an anisotropic dye film inferior in the heat resistance,
whereby the decrease in the order parameter by heating was large as
compared with Examples 2-1 to 6.
Comparative Example 2-2
[0177] 15 Parts of the above exemplified Dye No. (I-15) was added
to 85 parts of water, stirred and dissolved, followed by filtration
to obtain a dye composition for an anisotropic dye film. In the
same manner as in Example 2-1, this dye composition for an
anisotropic dye film was applied to a substrate, and the obtained
anisotropic dye film was subjected to a heat resistance test.
[0178] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0179] As is evident from Table 2, the obtained anisotropic dye
film was an anisotropic dye film inferior in the heat resistance,
whereby the decrease in the order parameter by heating was large as
compared with Example 2-7.
Comparative Example 2-3
[0180] 16 Parts of the above exemplified Dye No. (I-15) and 5 parts
of glycerol were added to 79 parts of water, stirred and dissolved,
followed by filtration to obtain a dye composition for an
anisotropic dye film. In the same manner as in Example 2-1, this
dye composition for an anisotropic dye film was applied to a
substrate, and the obtained anisotropic dye film was subjected to a
heat resistance test.
[0181] The order parameter measured before and after the heat
resistance test of the obtained anisotropic dye film, and its
decrease, are shown in Table 2.
[0182] As is evident from Table 2, the obtained anisotropic dye
film was an anisotropic dye film inferior in the heat resistance,
whereby the order parameter before the heat resistance test was low
as compared with Example 2-7, and the decrease in the order
parameter by heating was large. TABLE-US-00002 TABLE 2 Order
parameter Before After Decrease heat heat in order Dye resistance
resistance parameter Examples No. Additive test test (%) Example
2-1 (I-3) L- 0.89 0.87 2.2 phenylalanine Example 2-2 .beta.-alanine
0.86 0.84 2.3 Example 2-3 4-Hydroxy-L- 0.88 0.84 4.5 proline
Example 2-4 L-aspargine 0.89 0.88 1.1 monohydrate Example 2-5
L-asparginic 0.88 0.85 3.4 acid Example 2-6 L-glutamic 0.86 0.83
3.5 acid Comparative Nil 0.84 0.80 4.8 Example 2-1 Example 2-7
(I-15) L-proline 0.88 0.85 3.4 Comparative Nil 0.82 0.78 4.9
Example 2-2 Comparative Glycerol 0.72 0.68 5.6 Example 2-3
INDUSTRIAL APPLICABILITY
[0183] The anisotropic dye film of the present invention is useful
for various polarizing elements such as polarizing plates provided
on display devices such as light control devices, liquid crystal
devices (LCD) or organic electroluminescence devices (OLED).
[0184] The present invention is based on a Japanese Patent
Application No. 2004-10283 (filed on Jan. 19, 2004), a Japanese
Patent Application No. 2004-149375 (filed on May 19, 2004) and a
Japanese Patent Application No. 2004-376442 (filed on Dec. 27,
2004), and their entireties are hereby included by reference.
* * * * *