JP2004091649A - Water-based ink composition for writing utensil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based ink composition for a writing utensil, having excellent so-called cap-off properties (dry-up resistant properties) such as resistance to blur and impossibility of writing caused by drying of a penpoint caused when the writing utensil is left in a cap-off state for a long time, and hardly causing reduction of ink performances such as the local viscosity change and pH change of the ink. <P>SOLUTION: The water-based ink composition for the writing utensil comprises at least water, a coloring agent and a salt of pantothenic acid, and the content of the salt of the pantothenic acid is regulated within a range of 0.1-20.0 wt.%. <P>COPYRIGHT: (C)2004,JPO

Description

【００４１】
【発明の効果】
本発明は、キャップオフ性を改良するために過剰量の水溶性有機溶剤を含有させたインキ組成物に発生していた粘度上昇や、尿素及び／又は尿素誘導体を配合したインキ組成物の高温下における尿素類の分解によるインキへの悪影響等の問題点を解消し、良好な安定性、優れた耐ドライアップ性を備えた筆記用水性インキ組成物を提供することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aqueous ink composition for a writing instrument. More specifically, a water-based writing instrument with excellent dry-up resistance (cap-off performance) that suppresses the occurrence of blurring and writing impairment due to drying of the pen tip even when left for a long time with the cap removed. The present invention relates to an ink composition.
[0002]
[Prior art]
Conventionally, a water-soluble organic solvent, urea, and / or a urea derivative have been used as an anti-drying agent for a pen tip of a water-based ink for writing implements. In recent years, in order to improve the robustness of handwriting, ink compositions for writing implements using pigments as colorants have been widely used, but pigment-based inks dry faster at the pen tip compared to dye-based inks. However, there is a drawback that the writing property does not recover even when the cap is attached and left after drying.
[0003]
In the field of water-based ballpoint pens, there are many so-called "gel ballpoint pens" having a structure in which a shear-thinning ink is directly stored in an ink storage tube and an ink backflow prevention member is provided at the rear end of the ink. The inks used in ballpoint pens include gums such as xanthan gum and succinoglycan, crosslinked acrylic acid polymers, nonionic surfactants having an HLB value of 8 to 12 and associated urethane as shear thinning agents. Has been proposed and put into practical use. However, any of these shear-thinning agents can easily form a strong dry film when moisture evaporates at the pen tip, so that the dry-up resistance may be significantly degraded.
[0004]
Therefore, in the shear-thinning water-based ballpoint pen ink, it is necessary to further improve the dry-up resistance, and attempts have been made to increase the amount of the water-soluble organic solvent, urea and / or a derivative thereof.
[0005]
However, for example, a water-soluble organic solvent represented by a polyhydric alcohol such as glycerin or ethylene glycol requires a large amount of addition in order to obtain sufficient dry-up resistance. And various problems such as poor ink followability, poor handwriting drying, and handwriting bleeding.
Although urea and / or urea derivatives have some improvement in dry-up resistance, they are decomposed by storage in a high-temperature environment to generate ammonia, raise the pH of the ink, and perform solid analysis at the pen tip. In some cases, the performance of the writing instrument may be degraded, for example, inducing the outflow.
[0006]
Although the water-soluble organic solvent, urea and / or urea derivative and the like exhibit high dry-up resistance due to high water absorption performance, these conventional inks in which a dry-up resistance imparting agent is excessively added are subjected to high humidity conditions. If the writing implement is left below, there is a problem in the stability of the ink, such as local absorption of water at the pen tip.
[0007]
[Problems to be solved by the invention]
The present invention solves the above problem, that is, to provide an aqueous ink composition which can provide excellent handwriting without bleeding without changing the viscosity of the ink and can impart dry-up resistance. Is what you do.
[0008]
[Means for Solving the Problems]
The present invention requires that the ink composition comprises at least water, a colorant, and a pantothenate, and that the ink composition contains the pantothenate in an amount of 0.1 to 20.0% by weight. I do.
[0009]
The pantothenate used in the present invention is a salt of pantothenic acid, which is a kind of vitamin B group widely present in nature, and includes alkali metals such as lithium, sodium and potassium; alkaline earth metals such as magnesium and calcium; and zinc. And the like.
By adding the pantothenate to the ink, excellent dry-up resistance can be imparted.
[0010]
The pantothenate is incorporated in an amount of 0.1 to 20.0% by weight, preferably 1.0 to 10.0% by weight, based on the total amount of the ink composition. If the amount is less than 0.1% by weight, the effect of dry-up resistance is hardly obtained. If the amount is more than 20.0% by weight, the added salt cannot be completely dissolved, the solid content in the ink increases, and the viscosity of the ink increases. It may cause crying and pilling, and may degrade the cap-off performance.
[0011]
As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof are shown below.
As acid dyes,
New coccin (CI. 16255),
Tartrazine (CI. 19140),
Acid Blue Black 10B (CI. 20470),
Guinea Green (CI. 42085),
Brilliant blue FCF (CI. 42090),
Acid Violet 6BN (CI. 43525),
Soluble Blue (C.I. 42755),
Naphthalene green (CI.44025),
Eosin (C.I. 45380),
Phloxine (CI. 45410),
Erythrosine (CI. 45430),
Nigrosine (C.I. 50420),
Acid flavin (CI. 56205) and the like are used.
[0012]
As basic dyes,
Chrysoidin (CI. 11270),
Methyl violet FN (CI. 42535),
Crystal violet (CI. 42555),
Malachite green (CI.42000),
Victoria Blue FB (CI.44045),
Rhodamine B (CI. 45170),
Acridine orange NS (CI. 46005),
Methylene blue B (CI. 52015) and the like are used.
[0013]
As a direct dye,
Congo Red (CI. 22120),
Direct Sky Blue 5B (CI. 24400),
Violet BB (CI. 27905),
Direct deep black EX (CI. 30235),
Kayalas Black G Conch (CI. 35225),
Direct Fast Black G (CI. 35255),
Phthalocyanine blue (CI. 74180) and the like are used.
[0014]
As the pigment, carbon black, inorganic pigments such as ultramarine blue and other organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as being already finely and stably dispersed in an aqueous medium using a surfactant or a water-soluble resin. Water-dispersed pigment products and the like are used, for example, as a water-dispersed pigment using a surfactant,
C. I. Pigment Blue 15: 3B [trade name: Sandy Super Blue GLL, pigment content 24%, Sanyo Dyeing Co., Ltd.],
C. I. Pigment Red 146 [trade name: Sandy Super Pink FBL, pigment content: 21.5%, Sanyo Dyeing Co., Ltd.],
C. I. Pigment Yellow 81 (trade name: TC Yellow FG, pigment content: about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.),
C. I. Pigment Red 220/166 [trade name: TC Red FG, pigment content: about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.] and the like.
In addition, as a water-dispersed pigment using a water-soluble resin,
C. I. Pigment Black 7 (trade name: WA color Black A250, pigment content 15%, manufactured by Dainichi Seika Kogyo Co., Ltd.),
C. I. Pigment Green 7 (trade name: WA-S color Green, pigment content 8%, manufactured by Dainichi Seika Kogyo Co., Ltd.),
C. I. Pigment Violet 23 (trade name: MicroPigmo WMVT-5, pigment content 20%, manufactured by Orient Chemical Industry Co., Ltd.),
C. I. Pigment Yellow 83 (trade name: Emacol NS Yellow 4618, pigment content: 30%, manufactured by Sanyo Dyeing Co., Ltd.).
[0015]
As the fluorescent pigment, a synthetic resin fine particle-shaped fluorescent pigment in which various fluorescent dyes are made into a solid solution in a resin matrix can be used. Other examples include pearl pigments, metal powder pigments, luminous pigments, white pigments such as titanium dioxide, silica and calcium carbonate, capsule pigments containing a thermochromic composition, capsule pigments containing fragrances and fragrances, and the like.
Examples of the metallic luster pigment include metallic luster pigments such as aluminum and brass, and metallic luster pigments obtained by coating the surface of natural mica, synthetic mica, glass fragments, alumina, and transparent film fragments with a metal oxide such as titanium oxide. (Pearl pigments), metallic luster pigments formed by forming a metal vapor-deposited film on a transparent or colored transparent film, and metallic luster pigments having iris obtained by finely cutting an iris film obtained by laminating a plurality of transparent resin layers.
Further, when a metallic luster pigment such as aluminum or brass is used, a pigment obtained by coating the surface of the metallic luster pigment with a transparent resin or a colored transparent resin is preferably used, and is excellent in stability in the ink composition.
As the metallic luster pigment coated with the transparent resin or the like, specifically, a flat metal powder coated on both sides with a transparent or colored transparent resin film can be exemplified.
One or more kinds of the colorants can be used as appropriate, and can be used in an appropriate mixture.
[0016]
When a pigment is used as a colorant, a pigment dispersant can be added as needed. Examples of the pigment dispersant include surfactants such as anions and nonions, anionic polymers such as polyacrylic acid and styrene acrylic acid, and nonionic polymers such as PVP and PVA.
[0017]
Further, a water-soluble organic solvent can be added as required.
Examples of the water-soluble organic solvent include, for example, ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, N-methyl-2- Pyrrolidone, and the like.
The water-soluble organic solvents may be used alone or in combination of two or more, and are used in the range of 3 to 30% by weight.
[0018]
In addition to the above components, if necessary, sodium carbonate, sodium phosphate, inorganic salts such as sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, benzotriazole and its derivatives, tolyltriazole, dicyclohexylammonium Corrosion inhibitors such as nitrite, diisopropylammonium nitrite, sodium thiosulfate, saponin, sodium carbonate, 1,2-benzthiazolin-3-one sodium salt, sodium benzoate, sodium dehydroacetate, potassium sorbate, paraoxybenzoic acid Preservatives or fungicides such as propyl, 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine, metal soaps, polyalkylene glycols, fatty acid esters, ethylene oxide-added cationic activators, phosphoric acid-based activities Agent, thioca Lubricants such as bamate and dimethyldithiocarbamate, wetting agents such as urea and sodium pyrophosphate, defoamers, dispersants, fluorine-based surfactants and nonionic surfactants that improve ink permeability. May be used.
[0019]
When the aqueous ink composition for a writing implement of the present invention is applied to a ballpoint pen of a type in which ink is directly accommodated in an ink accommodating tube to which a chip is attached directly or via a connecting member, the ink is added by adding a shear thinning agent. To give a suitable viscosity for practical use. The shear thinning agent used can be appropriately selected from conventionally known ones, and specific examples thereof include xanthan gum, succinoglycan, polysaccharides such as carrageenan, polyacrylic acid, cross-linked acrylic acid, and polyvinyl acetamide. , Nonionic surfactants, anionic surfactants, and associative urethane emulsions.
[0020]
The structure and shape of the writing implement itself to be filled with the aqueous ink composition for a writing implement of the present invention are not particularly limited, and conventional general-purpose ones can be applied, such as a fiber tip, a felt tip, and a plastic tip. Ink is impregnated with ink into the ink occluding body consisting of fiber bundles housed inside the barrel, and ink is supplied to the tip of the writing head. A marking pen with a structure in which an ink flow rate adjustment member made of a member or a fiber bundle is interposed, a structure in which ink is directly stored inside the barrel, and a predetermined amount of ink is supplied to the writing tip by a valve mechanism, or in a barrel. It has an ink storage tube filled with the ink composition, and the ink storage tube communicates with a chip having a ball mounted at the tip, and an ink reverse surface for preventing backflow is provided on the end surface of the ink. Ballpoint pens and the prevention body is closely, writing unit is housed in the barrel in a state of being exposed to the air, knock-type, rotary, ball-point pen or the like having a retractable mechanism sliding the like.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
The aqueous ink composition for a writing instrument of the present invention is prepared by adding a colorant and a pantothenate into an aqueous medium, and further adding an appropriate additive when an additive is added thereto, and heating and stirring as necessary. Then, it is prepared by dissolving or dispersing, and used by filling in a writing pen in the form of a marking pen such as a ball-point pen, a felt-tip pen and a felt-tip pen, a fountain pen and a brush pen.
[0022]
【Example】
Examples are shown below, but the present invention is not limited to these examples. The numerical values represent parts by weight.
[0023]
Example 1
Black pigment 45.0
[Product name: WA Black A250, manufactured by Dainichi Seika Kogyo Co., Ltd .; pigment 15%, diethylene glycol 20%, acrylic resin 6%, water balance]
Glycerin 10.0
Sodium pantothenate 1.0
Water 44.0
Total 100.0
[0024]
The components were stirred with a propeller-type stirrer to obtain a black aqueous ink.
[0025]
Example 2
Black dye 40.0
[Product name: Water Black 100L, manufactured by Orient Chemical Industry Co., Ltd .; I. Direct black 19 20%, water 80%]
Glycerin 10.0
Potassium pantothenate 3.0
Water 47.0
Total 100.0
[0026]
The components were stirred with a propeller-type stirrer to obtain a black aqueous ink.
[0027]
Example 3
Blue dye 15.0
[Product name: Brilliant Blue FCF-L, manufactured by Daiwa Kasei Co., Ltd .; I. Acid Blue 9 35% aqueous solution]
Ethylene glycol 3.0
Calcium pantothenate 10.0
Wed 72.0
Total 100.0
[0028]
The components were stirred with a propeller-type stirrer to obtain a blue aqueous ink.
[0029]
Example 4
Orange fluorescent pigment 50.0
[Product name: Lumicoll NKW-3004, manufactured by Nippon Fluorescent Chemical Co., Ltd .; nonvolatile content: 41.5%]
Glycerin 10.0
Sodium pantothenate 3.0
Water 37.0
Total 100.0
[0030]
The components were stirred with a propeller-type stirrer to obtain an orange fluorescent aqueous ink.
[0031]
Example 5
Yellow fluorescent pigment 50.0
[Product name: Lumicoll NKW-3005, manufactured by Nippon Fluorescent Chemical Co., Ltd .; nonvolatile content: 42.0%]
Glycerin 10.0
Sodium pantothenate 5.0
Water 35.0
Total 100.0
[0032]
The components were stirred with a propeller-type stirrer to obtain a yellow fluorescent aqueous ink.
[0033]
Comparative Example 1
A black aqueous ink was obtained in the same manner as in Example 1, except that sodium pantothenate in the composition of Example 1 was replaced with the same amount of water.
[0034]
Comparative Example 2
A black aqueous ink was obtained in the same manner as in Example 2 except that potassium pantothenate in the composition of Example 2 was replaced with the same amount of water.
[0035]
Comparative Example 3
A blue aqueous ink was obtained in the same manner as in Example 3, except that the calcium pantothenate in the composition of Example 3 was replaced with the same amount of water.
[0036]
Comparative Example 4
An orange fluorescent aqueous ink was obtained in the same manner as in Example 4, except that sodium pantothenate in the composition of Example 4 was replaced with the same amount of water.
[0037]
Comparative Example 5
A yellow fluorescent aqueous ink was obtained in the same manner as in Example 5, except that sodium pantothenate in the composition of Example 5 was replaced with the same amount of water.
[0038]
Each of the inks of Examples 1 to 5 and Comparative Examples 1 to 5 obtained by the above blending and preparation methods was filled in a commercially available marking pen [product number: SGR-8SL, manufactured by Pilot Corporation] to prepare a sample. A marking pen was prepared and the following performance comparison test was performed.
[0039]
After assembling the dry-up test, the sample marker, which was confirmed to be writable, was left horizontally in a room and in a constant temperature bath at 20 ° C. and 65% RH with the pen tip exposed. When handwriting was performed by hand, the standing time required until abnormalities (scratch, density change, etc.) occurred in the handwriting was confirmed.
The results of the test are shown in the table below.
[0040]
[Table 1]

[0041]
【The invention's effect】
The present invention relates to an ink composition containing an excessive amount of a water-soluble organic solvent for improving the cap-off property. In addition, it is possible to provide a water-based ink composition for writing having good stability and excellent dry-up resistance by solving problems such as adverse effects on ink due to decomposition of urea in the above.

Claims (2)

An aqueous ink composition for a writing instrument, comprising at least water, a colorant, and a pantothenate. The aqueous ink composition for a writing instrument according to claim 1, wherein the pantothenate is contained in an amount of 0.1 to 20.0% by weight in the ink composition.