Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2002-05-17
2004-12-14
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031280, C106S031580
Reexamination Certificate
active
06830611
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink composition suitable for use as an oil-based ink composition for writing instruments and having excellent properties in the solubility of the dye in an ink and in the compatibility with other raw materials, and also relates to writing instruments using the ink composition and a novel dye for the ink composition.
BACKGROUND ART
The oil-based black ink heretofore used is predominantly an inexpensive nigrosine in view of the cost or a metal complex salt dye in view of the fastness. However, the nigrosine has a problem in the solubility or compatibility with other raw materials and the metal complex salt dye is disadvantageously low in the concealing property. Accordingly, in the case of using the metal complex salt dye, this dye is, in many cases, used in combination with a triphenylmethane-base (triarylmethane-based) dye giving good coloration but, depending on the solvent or other raw materials used and the amounts added thereof, this causes troubles in the ink, such as extreme increase of the ink viscosity or the generation of precipitates. Also in the case where a pigment dispersion for imparting fastness is used in place of the metal complex salt dye, the same problems are generated on many occasions.
An object of the present invention is to provide an oil-based ink composition exhibiting good compatibility with a metal complex salt dye or other raw materials in an ink, ensuring excellent stability in aging at low temperatures, and containing a dye which can be added, during use of an alcohol having 2 or more carbon atoms, a polyhydric alcohol or a glycol ether, in a high concentration as a-dye for imparting a concealing property by forming a black or blue color and can be free of the above-described problems even under a high-concentration condition. The object of the present invention includes providing a dye useful therefor.
As for the triarylmethane-based dye used as a main dye of an ink for writing instruments, salt-forming dyes, using as a matrix a basic dye where the amino group introduced into the aromatic ring is a monomethylamino group and/or a dimethylamino group and/or a monophenylamino group, are known. Examples of such dyes are C.I. Basic Violet 1, C.I. Basic Violet 3 and C.I. Basic Blue 26.
However, in the case where this widely employed triphenylmethane-base dye and a metal complex salt dye are used in combination and dissolved in an alcohol having about 4 or fewer carbon atoms, a glycol or a glycol ether used as a solvent of an ink for writing instruments, the composition suffers from very poor stability and when left standing at low temperatures, precipitates are sometimes generated.
In the case of forming an ink for writing instruments by using these dyes, the dye concentration must be high to a certain degree to allow a drawn line to have a concealing power (necessary density of a drawn line), however, if the dye concentration is high, a precipitate is generated and the ink is not suitable as an ink for writing instruments.
These problems are more outstanding when a solvent having a high vapor pressure is used to obtain quick drying of the dawn line such as, for example, propylene glycol monomethyl ether.
The present invention has been made by taking account of these problems in conventional techniques. Another object of the present invention is to provide a triarylmethane-based, particularly a triphenylmethane-based, dye suitable for an ink for writing instruments which exhibits excellent flowability and good stability even when used in combination with a metal complex salt and dissolved in an alcohol having about 4 or fewer carbon atoms, a glycol or a glycol ether, particularly a propylene glycol monomethyl ether, commonly used as a solvent of an ink for writing instruments.
DISCLOSURE OF THE INVENTION
In order to attain the above-described objects, the present invention provides the following.
(1) An ink composition comprising at least one triarylmethane-based dye as a coloring material, an alcohol having 2 or more carbon atoms, a polyhydric alcohol or a glycol ether as a solvent, and a resin which can dissolve in the solvent, said triarylmethane-based dye being represented by the following formula:
wherein Ar is an aryl group substituted, or not substituted, by a halogen or an alkyl group, Y is a diethylamino group or hydrogen, provided that at least two Y are a diethylamino group, A is a halogen or an organic acid group, and A is charge-balanced to the residue.
(2) The ink composition as above, wherein three aryl groups in the dye all are a phenyl group.
(3) The ink composition as above, wherein three Y in the dye all are a diethylamino group.
(4) The ink composition as above, wherein all aryl groups in the dye are not substituted by a halogen or an alkyl group.
(5) The ink composition as above, wherein the dye is a compound where A is an organic acid group, and dissolves in an alcohol having 2 or more carbon atoms, a polyhydric alcohol or a glycol ether used as a solvent, to a concentration of 20 mass % or more.
(6) The ink composition as above, wherein A in the dye is an organic acid group selected from the group consisting of a carboxyl group, an acyl group, a thiocarboxyl group, a dithiocarboxyl group, a sulfonic acid group, a sulfinic acid group, a sulfenic acid group, a sulfoamino group, a mercapto group, a phenolic hydroxyl group, a hydroxyamino group and a hydroxyimino group.
(7) The ink composition as above, wherein A in the dye is an acid group of an organic acid selected from the group consisting of adipic acid, acetoacetic acid, anisic acid, abietic acid, benzoic acid, succinic acid, citric acid, phthalic acid, oleic acid, stearic acid, linoleic acid, linolenic acid, toluic acid, naphthoic acid, palmitic acid, hydroxybenzoic acid, cinnamic acid, hydroxycinnamic acid, pimaric acid, piperonylic acid, phenylpropionic acid, phenoxyacetic acid, mandelic acid, maleic acid, rosin-modified maleic acid, hexanethiocarboxylic acid, hexanedithiocarboxylic acid, laurylsulfonic acid, 1-piperidinesulfinic acid, benzenesulfenic acid, ethanesulfinyl chloride, phenylmethanethiol, benzenedithiol, phenylhydroxylamine, hydroxyaminophenol, cyclohexanoneoxime, benzaldehydeoxime, laurylphosphoric acid ester, dinonylphenylphosphoric acid ester, anthranilic acid and hippuric acid.
(8) The ink composition as above, wherein A in the dye contains an aromatic ring having at least one sulfonic acid group.
(9) The ink composition as above, wherein A in the dye is selected from the group consisting of anionic surfactants such as alkylbenzenesulfonic acid and salts thereof, alkylnaphthalenesulfonic acid and salts thereof, alkylarylsulfonate formalin condensate and salts thereof, and alkyldiphenyletherdisulfonic acid and salts thereof, and acidic dyes such as C.I. Acid orange 7, C.I. Acid Yellow 36 and C.I. Acid Red 88.
(10) The ink composition as above, which further contains a metal complex salt dye or a pigment.
(11) The ink composition as above, which contains at least polyvinylbutyral as said resin.
(12) The ink composition as above, wherein the solvent comprising an alcohol having 2 or more carbon atoms, a polyhydric alcohol or a glycol ether and being an aliphatic solvent occupies 40 mass % or more of the entire solvent of the ink composition.
(13) The ink composition as above, wherein the solvent contains at least one of the following solvents i) to iii) as the main solvent:
i) a solvent represented by the chemical formula: C
n
H
2n+1
OC
3
H
6
OH wherein n is an integer of 1 to 3;
ii) a propylene glycol monomethyl ether; and
iii) a solvent represented by the following structural formula (2):
wherein R
1
, R
2
and R
3
each is independently H or CH
3
.
(14) A writing instrument comprising the above-described ink composition.
(15) The writing instrument as above, which is a sign pen.
(16) The writing instrument as above, which is a ballpoint pen.
(17) The writing instrument as above, which is an ink stamp pad.
(18) A dye represented by the following formula (3):
wherein each Ar is inde
Ichikawa Shuuji
Ikai Takayuki
Foley & Lardner LLP
Klemanski Helene
Mitsubishi Pencil Co. Ltd.
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