Compositions: coating or plastic – Coating or plastic compositions – Marking
Reexamination Certificate
2000-05-23
2002-09-17
Klemanski, Helene (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Marking
C106S031360, C106S031380, C106S031580, C106S031680, C106S031700
Reexamination Certificate
active
06451099
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a water based ink composition for a ball point pen.
BACKGROUND ART
In order to know a remaining amount of an ink in a ball point pen using a water based ink, a method in which an ink itself having an increased viscosity is stored in a transparent ink reservoir of a ball point pen has so far been employed.
This water based ink composition used for a ball point pen contains a dye and/or a pigment as a colorant, and a water-soluble solvent such as a glycol and glycerin is used in addition to water of a principal solvent in order to inhibit the ink from drying at a pen tip (non-dry property). However, the water based ink composition according to the recipe described above can not provide satisfactory lubricity, and causes writing to be impossible due to abrasion of a ball housing. On the other hand, even if the satisfactory lubricity is obtained, there has been the problem that an ink is notably reduced in a surface tension, so that writings are liable to be blurred.
Then, a water based ink composition for a ball point pen comprising an alkylene oxide adduct of polyglycerin and the like, a colorant, a thickener and water was applied for a patent (Japanese Patent Application Laid-Open No. 8-302267) by the present inventors as a water based ink composition for a ball point pen which is excellent in lubricity and provides writings less liable to be blurred and which is excellent in a non-drying property.
However, this water based ink composition for a ball point pen is a little inferior in a coloring property of the drawn lines. When written on a paper face having a dark color such as black and dark blue, particularly on a paper face of a drawing paper having a coarse texture, the ink is penetrated, and the color of the drawn lines becomes a little indistinct. Further, included is the problem that the visual color observed when looking at the ink reservoir from the outside thereof is different from the color of the drawn lines, that is, the displaying property is inferior. Further, there is the problem that use of two or more kinds of colorants (pigments) having different specific gravities brings about degradation (settling of the pigments) of the ink with the passage of time.
The present invention has been made in order to solve the problems described above, and an object of the present invention is to provide a water based ink composition for a ball point pen which is excellent in an ink coloring property of the drawn lines and a displaying property and which is excellent in dispersion stability with the passage of time and has good writing feeling.
DISCLOSURE OF THE INVENTION
Intensive researches continued by the present inventors in order to solve the problems described above have resulted in successfully obtaining a water based ink composition for a ball point pen which meets the object described above by adding a specific component and a white plastic pigment to the ink composition, and thus completing the present invention.
That is, the water based ink composition of the present invention for a ball point pen comprises the following items (1) to (6).
(1) A water based ink composition for a ball point pen comprising at least one selected from the group consisting of an alkylene oxide adduct of polyglycerin, an alkylene oxide adduct of glycerin and an alkylene oxide adduct of trimethylolpropane and further comprising a colorant, a white plastic pigment, a viscosity-controlling agent and water.
(2) The water based ink composition for a ball point pen as described in the above item (1), comprising at least one selected from the group consisting of an alkylene oxide adduct of polyglycerin, an alkylene oxide adduct of glycerin and an alkylene oxide adduct of trimethylolpropane in a proportion of 0.5 to 40% by weight based on the total amount of the ink composition.
(3) The water based ink composition for a ball point pen as described in the above item (1) or (2), comprising titanium oxide as the colorant in a proportion of 0.1 to 30% by weight based on the total amount of the ink composition.
(4) The water based ink composition for a ball point pen as described in the above item (1) or (2), comprising titanium oxide as the colorant and further comprising at least one selected from the group consisting of inorganic pigments, organic pigments and pseudo-pigments prepared by coloring a resin emulsion with a dye, wherein the colorants have a content of 0.1 to 50% by weight based on the total amount of the ink composition.
(5) The water based ink composition for a ball point pen as described in any of the above items (1) to (4), comprising at least one kind of hollow resin particles having voids in the inside of the particles as the white plastic pigment in a proportion of 1.0 to 30% by weight based on the total amount of the ink composition in terms of a solid content.
(6) The water based ink composition for a ball point pen as described in any of the above items (1) to (5), comprising at least one selected from the group consisting of synthetic polymers, natural gums, celluloses and polysaccharides as the viscosity-controlling agent, wherein the viscosity at a shearing rate of 3.84 s
−1
is 300 to 4,000 mPa·s.
BEST MODE FOR CARRYING OUT THE INVENTION
The embodiment of the present invention shall be explained below in detail.
The water based ink composition for a ball point pen of the present invention is characterized by comprising at least one selected from the group consisting of an alkylene oxide adduct of polyglycerin, an alkylene oxide adduct of glycerin and an alkylene oxide adduct of trimethylolpropane and further comprising a colorant, a white plastic pigment, a viscosity-controlling agent and water.
At least one selected from the group consisting of an alkylene oxide adduct of polyglycerin, an alkylene oxide adduct of glycerin and an alkylene oxide adduct of trimethylolpropane, and a mixture thereof are used as a lubricant or a lubricity-improving agent, that is, for the purpose of improving smooth writing feeling and a grade of the drawn lines.
To describe in further details, if added in a large amount is a lubricant usually added to a water based ink composition for a ball point pen, for example, potassium linoleate, sodium ricinoleate, potassium oleate, sodium oleate and phosphoric acid esters, an adverse effect is exerted on the stability of the ink. Accordingly, in the water based ink composition for a ball point pen of the present invention, a certain amount (0.1 to 3.0% by weight based on the total amount of the ink composition) of these lubricants and the alkylene oxide adduct described above as the lubricant of the present invention is added, so that the lubricity and the stability are further improved, and the intended smooth writing feeling and a rise in the grade of the drawn lines are attained. On the other hand, when the lubricant such as sodium oleate and phosphoric acid esters is not added, the respective alkylene oxide adducts described above are not so effective as these lubricants in the water based ink composition for a ball point pen of the present invention, but provide the ink with the smoother writing feeling and a more rise in the grade of the drawn lines than the case of adding no lubricants without exerting an adverse effect on the stability of the ink as the lubricity-improving agent.
In the present invention, the respective alkylene oxide adducts described above have a content of 0.5 to 40% by weight, preferably 5 to 20% by weight based on the total amount of the ink composition.
The alkylene oxide adduct of polyglycerin is obtained by adding 1 to 60 moles of alkylene oxide to polyglycerin having a polymerization degree of 2 to 4 and includes, for example, at least one obtained by adding 1 to 60 moles of ethylene oxide, propylene oxide or a mixture thereof to a polymer of 2 to 4 moles of glycerin such as diglycerin and triglycerin.
The alkylene oxide adduct of glycerin is obtained by adding 1 to 150 moles, preferably 11 to 60 moles of alkylene oxide to glycerin and includes, for example, at l
Kamagata Tadashi
Miyamoto Masaru
Shinozuka Miki
Faison Veronica F.
Klemanski Helene
Mitsubishi Pencil Kabushiki Kaisha
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