Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
1999-04-06
2001-09-04
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S286100, C430S905000, C524S092000, C524S597000, C524S720000
Reexamination Certificate
active
06284432
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a coloring composition useful for producing a color filter used in a color liquid crystal display, color video camera and the like.
DESCRIPTION OF THE RELATED ART
A color filter used in a color liquid crystal display, color video camera and the like is usually produced by forming three transparent colored fine patterns of red (R), green (G) and blue (B) on a transparent substrate such as glass or an opaque substrate such as silicon. For forming three transparent colored fine patterns, a so-called dyeing method has been often adopted in which a photosensitive layer such as a layer made of gelatin is patterned by photolithography and dyeing, and this procedure is repeated three-times. Since conventional dyes usable in such a dyeing method have limited light-resistance and heat-resistance, although excellent in color property, organic pigments excellent in light-resistance and heat-resistance have been increasingly used as coloring materials for producing color filters instead of dyes.
When a color filter is produced using an organic pigment, a pigment is generally dispersed in a dispersing medium composed of a resin and a solvent to prepare a coloring composition for a color filter, then, the resulting coloring composition is applied on a substrate to form a coated film. Fine color elements are formed on the coated film by a photolithography method, printing method, electrodeposition method and the like.
However, when a conventional coloring composition for a color filter is used, dispersion of the pigment is unstable and coagulation tends to occur. Therefore, it has been difficult to produce a color filter excellent in contrast (maintenance of polarization). For applying such a coloring composition onto a substrate, a spin coat method is usually adopted in which the coloring composition is dropped on the substrate and the substrate was rotated at high speed to spread the composition. However, when a conventional coloring composition for a color filter is spin-coated, film thickness of center part remarkably increases and a uniform coat can not be obtained easily.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a coloring composition in which the pigment dispersion is stable and hardly causes coagulation, and which can produce a color filter excellent in contrast. Another object of the present invention is to provide a coloring composition for a color filter which does not cause increase in thickness of the central part when spin-coated and provides a uniform coat.
The present inventors have intensively investigated using commercially available organic pigments for solving the above-described problems. As a result, they have found that the above objects can be attained by using a specific pigment derivative as an additive. The present invention was thus completed.
Namely, the present invention provides a coloring composition for a color filter, which comprises (i) an organic pigment, (ii) a binder, and (iii) a pigment derivative which is an organic pigment to which a sulfonate group and a sulfonamide group are bonded or a salt thereof.
As the organic pigment to which a sulfonate group and a sulfonamide group are bonded, compounds represented by the following formula (I) can be specifically listed.
wherein, D represents an organic pigment residue;
R
1
represents a hydrogen atom or a hydrocarbon residue which may be substituted;
X represents a group —C
k
H
2k
NR
2
R
3
, wherein k represents a number from 1 to 10, and R
2
and R
3
each independently represents a hydrocarbon residue which may be substituted, or R
2
, R
3
and the nitrogen atom to which R
2
and R
3
are bonded together form a hetero ring which may optionally contain another hetero atom selected from nitrogen, oxygen and sulfur as a ring atom, or X represents an alkyl group which is substituted with a hetero ring containing at least one hetero atom selected from nitrogen, oxygen and sulfur as a ring atom, the alkyl group bonding to a carbon atom in the hetero ring; or
R
1
, X and the nitrogen atom to which R
1
and X are bonded together form a hetero ring containing at least one other nitrogen atom as a ring atom;
m represents a number from 0.5 to 3; and
n represents a number from 0.5 to 3.5.
The total of m and n is preferably in the range from 1 to 5.
The organic pigment which residue is to be bonded to a sulfonate group and a sulfonamide group to form the pigment derivative (iii) is optionally the same as organic pigment (i), although, in general, it is advantageous that they are identical.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Examples of the organic pigment which residue is to be bonded to a sulfonate group and a sulfonamide group to form the pigment derivative (iii) include condensed azo, triphenodioxadine, dianthraquinonyl, benzimidazolone, anthrapyrimidine, flavanthorone, antanethorone, indanethorone, pyranthorone, violanthorone, isoviolanthorone, quinacridone, quinophtharone, phthalocyanine, diletopyrrolopyrrole, isoindolinone, perynone, perylene, thioindigo pigments and the like. Residues of these pigments, namely, groups obtained by removing suitable number of hydrogen atoms from these pigment skeletons can be D in the formula (I).
Specific examples of the organic pigment which residue is to be bonded to a sulfonate group and a sulfonamide group to form the pigment derivative (iii) include condensed azo pigments represented by the following formula (II):
such as compounds known as C. I. Pigment Red 242, triphenodioxadine pigments represented by the following formula (III):
such as compounds known as C. I. Pigment Violet 23, dianthraquinonyl pigments represented by the following formula (IV):
such as compounds known as C. I. Pigment Red 177 and the like.
In the formula, R
1
may be a hydrogen atom or a hydrocarbon residue, and the hydrocarbon residue may have a substituent. The hydrocarbon residue represented by R
1
may be any of aliphatic, aromatic and aromatic aliphatic compounds. The aliphatic hydrocarbon residue represented by R
1
preferably has about 1 to 10 carbon atoms. The aromatic hydrocarbon residue represented by R
1
preferably has about 6 to 10 carbon atoms. The aromatic aliphatic hydrocarbon residue represented by R
1
preferably has about 7 to 10 carbon atoms. The aliphatic hydrocarbon residues represented by R
1
includes alkyl, alkenyl and alkynyl groups and the like, and more preferably is an alkyl group having 1 to 6 carbon atoms. The aromatic hydrocarbon residues include phenyl, alkyl-substituted phenyl and naphthyl groups and the like. The aromatic aliphatic hydrocarbon residues include benzyl, phenethyl, nuclear alkyl-substituted benzyl groups and the like. Examples of the group which can be substituted on these hydrocarbon residues include amino groups which are unsubstituted or mono- or di-substituted with an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 1 to 6 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms which are unsubstituted or substituted with a hydroxy group or an alkoxy group having 1 to 6 carbon atoms.
In the formula (I), X may represent a group —C
k
H
2k
NR
2
R
3
, wherein k represents a number from 1 to 10, and R
2
and R
3
each independently represents a hydrocarbon residue which may be substituted or R
2
, R
3
and the nitrogen atom to which R
2
and R
3
are bonded together form a hetero ring which may optionally contain another hetero atom selected from nitrogen, oxygen and sulfur as a ring atom. The alkylene group represented by —C
k
H
2k
may be straight, or branched when k is 2 or more, although, usually, straight is advantageous. The alkylene group represented by —C
k
H
2k
preferably contains 1 to 6 carbon atoms.
The hydrocarbon residue represented by R
2
or R
3
may be any of aliphatic, aromatic and aromatic aliphatic groups. The aliphatic hydrocarbon residue represented by R
2
or R
3
preferably has about 1 to 20 carbon atoms. The aromatic hydrocarbon residue represented by R
2
or R
3
preferably has about 6 to 20 carbon at
Furubayashi Toshiki
Ito Keisuke
Yamamoto Kaori
Baxter Janet
Birch & Stewart Kolasch & Birch, LLP
Clarke Yvette M.
Sumitomo Chemical Company Limited
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