Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-10-10
2004-10-05
Shosho, Callie (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S358000
Reexamination Certificate
active
06800674
ABSTRACT:
TECHNICAL FIELD
The present invention relates to ink for ink jet recording which is appropriately used in an ink jet recording system. More specifically, it relates to anthraquinone compounds useful as magenta coloring matters of aqueous ink for ink jet recording, and aqueous ink for ink jet recording using the same.
BACKGROUND OF THE INVENTION
As ink for recording of an ink jet recording system, aqueous ink has been ordinarily used. Aqueous ink is basically made of a coloring matter, water and an organic solvent. In consideration of an odor and safety to the human body and the surrounding environment, it is ink-containing water as a main solvent.
Further, as a coloring matter, water-soluble dyes such as acid dyes, basic dyes, reactive dyes, direct dyes and the like are generally used.
With respect to ink for ink jet recording and a coloring matter, the following various characteristics are required. That is,
(1) physical properties such as viscosity, surface tension, specific conductivity, density, pH and the like of ink are appropriate,
(2) long-term storage stability of ink is good,
(3) dissolution stability of a soluble component is high and clogging of a nozzle does not occur,
(4) quick-drying property of a recording medium is good, and
(5) a recorded image is sharp, and light fastness and water resistance are good. However, all these characteristics have not been satisfied at present.
Especially, in aqueous ink ordinarily used, a water-soluble dye is employed. Accordingly, there is such a serious problem in water resistance that when water is splashed on a recorded image, a dye is eluted to blot or lose a recorded image. Therefore, various studies have been currently made upon focussing on the improvement of water resistance.
For example, ink using a pigment or an oil-soluble dye as a coloring matter, a method in which an organic solvent, a resin or the like is added to aqueous ink using a water-soluble dye and the like have been studied. However, the use of a pigment was problematic in that dispersion stability was poor; storage stability was bad, clogging of a nozzle occurred, and so forth. Since an organic solvent was employed in case of using an oil-soluble dye, it posed problems in environmental sanitation, such as an odor and the like, or it was problematic in that ink blotting was heavy to invite the decrease in an image quality and so forth.
Moreover, even ink-containing additives involved problems that storage stability was poor, clogging of a nozzle occurred, ink was increased in viscosity to decrease jetting of ink and so forth.
Recently, ink using an aqueous dispersion in which a polyester resin colored with a dye or a pigment is used as a dispersoid is described in Japanese Patent Laid-Open No. 340,835/1994 or the like. Nevertheless, a pigment still involves the foregoing problems. A dye has also still problems that since it has poor compatibility with a resin, a precipitate appears in ink to decrease storage stability, to invite clogging of a nozzle and so forth.
As stated above, characteristics of ink used in an ink jet recording system in particular are greatly influenced by characteristics inherent in a coloring matter. It is thus quite important to produce a coloring matter that satisfies the foregoing required characteristics.
DISCLOSURE OF THE INVENTION
The invention aims to provide a coloring matter which is high in solubility in an organic solvent, excellent in water resistance and further excellent in light fastness and compatibility with a resin, and aqueous ink for ink jet recording of a magenta color type using the same, which aqueous ink is excellent in water resistance, light fastness and storage stability and most suitable for an ink jet recording system.
The present inventors have assiduously conducted investigations to solve the foregoing problems, and have consequently found that compounds represented by the formula (1) are coloring matters to meet the foregoing aim. This finding has led to the completion of the invention.
That is, the invention is as follows.
(1) Aqueous ink for ink jet recording which contains at least a water-insoluble coloring matter, water and a resin as main components to form an emulsion, characterized by containing at least one magenta coloring matter selected from anthraquinone compounds represented by the formula (1)
[wherein R
1
represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted aralkyl group or an alkoxycarbonylalkyl group, X represents an oxygen atom or a sulfur atom, R
2
to R
6
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group].
(2) The aqueous ink for ink jet recording recited in (1), wherein in the formula (1) recited in (1). R
1
is an optionally substituted aryl group represented by the formula (2)
[wherein R
7
to R
11
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group, an acyl group, —NR
12
R
13
(in which R
12
and R
13
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group or an acyl group) or —YR
14
(in which R
14
represents a hydrogen atom, an optionally substituted alkyl group, an acyl group or an alkoxycarbonylalkyl group, and Y represents an oxygen atom or a sulfur atom)], and X is an oxygen atom.
(3) The aqueous ink for ink jet recording recited in (2), wherein at least one of R
7
to R
11
in the formula (2) is —NR
12
R
13
.
(4) The aqueous ink for ink Jet recording recited in (3), wherein R
12
and R
13
in (3) are hydrogen atoms or optionally substituted alkyl groups.
(5) The aqueous ink for ink jet recording recited in (4), wherein R
8
in the formula (2) is —NR
12
R
13
, and R
12
and R
13
are both alkyl groups having the total carbon number of 4 or more.
(6) Resin fine particles colored with at least one magenta coloring matter selected from anthraquinone compounds represented by the formula (1)
[wherein R
1
represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted aralkyl group or an alkoxycarbonylalkyl group, X represents an oxygen atom or a sulfur atom, R
2
to R
6
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group].
(7) A dispersion formed by dispersing the colored resin fine particles recited in (6) in an aqueous medium.
(8) Anthraquinone compounds represented by the formula (1)
[wherein R
1
represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted aralkyl group or an alkoxycarbonylalkyl group, X represents an oxygen atom or a sulfur atom, and R
2
to R
6
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group or an optionally substituted alkoxy group].
(9) The anthraquinone compounds recited in (8), wherein in the formula (1) recited in (8), R
1
is an optionally substituted aryl group represented by the formula (2)
[wherein R
7
to R
11
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group, an acyl group, —NR
12
R
13
(in which R
12
and R
13
, independently from each other, represent a hydrogen atom, an optionally substituted alkyl group or an acyl group) or —YR
14
(in which R
14
represents a hydrogen atom, an optionally substituted alkyl group, an acyl group or an alkoxycarbonylalkyl group, and Y represents an oxygen atom or a sulfur atom)],
and X is an oxygen atom.
(10) The anthraquinone compounds recited in (9), wherein at least one of R
7
to R
11
in the formula (2) is —NR
12
R
13
.
(11) The anthraquinone compounds recited in (10), wherein R
12
and R
13
in (10) are hydrogen atoms or optionally substituted alkyl groups.
(12) The anthraquinone compounds recited in (11), wherein R
8
in the formula (2) is —NR
12
R
13
, and R
12
and R
13
are both alkyl groups having the total carbon number of
Kohgo Osamu
Matsuzaki Yoriaki
Oi Ryu
Okuma Tadashi
Burns Doane Swecker & Mathis L.L.P.
Mitsui Chemicals Inc.
Shosho Callie
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