JPH10195364A - Water-base pigment ink for ballpoint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink which is excellent in pigment dispersion and feeling during writing and stably flows out of a pen point during writing by adjusting the viscosity of a water-base pigment ink contg. at least two pigments and a water-soluble polymer into a specified range and adding an alkylene oxide adduct of a polyhydic alcohol to the ink. SOLUTION: An alkylene oxide adduct of a polyhydric alcohol is added to an ink contg. at least two pigments, water, a water-soluble polymer, and a water-soluble org. solvent and having a viscosity of 50-2,000mPa.s. The adduct is pref. an alkaline oxide adduct of polyglycerin, an alkylene oxide adduct of glycerin, or an alkylene oxide adduct of trimethylolpropane, still pref. an ethylene oxide adduct of digylcerin. The two pigments have properties and molecular structures or hues different from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous pigment ink for a ballpoint pen, the viscosity of which is adjusted by a water-soluble polymer.

[0002]

2. Description of the Related Art There is a conventional ballpoint pen using water-based ink for writing by drawing out ink impregnated in a fiber bundle by capillary force. In this method, the remaining amount and hue of the ink cannot be visually recognized, and the outflow of the ink is unstable. In addition, since the viscosity is low, there is a drawback that bleeding of a writing line easily occurs. For this reason, a ballpoint pen is used in which a pipe is filled with an aqueous ink whose viscosity has been adjusted by adding a water-soluble polymer in the same manner as an oil-based ballpoint pen. This ball-point pen does not require a fiber bundle or the like, so that the amount of the filled ink can be confirmed, and no bleeding of the writing line occurs. However, the water-based pigment ink whose viscosity has been adjusted by adding a water-soluble polymer has a reduced dispersion stability of the pigment, impairs the writing taste, causes agglomeration and sedimentation of the pigment over time, or writes. In this case, the performance tends to deteriorate, for example, the outflow of the ink becomes unstable. In particular, when two or more different types of pigments are used for the purpose of adjusting the hue, the tendency is remarkable.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems. That is, when using a water-soluble polymer as a dispersant for two or more different types of pigments, a water-soluble pigment for ballpoint pens in which the dispersion stability of the pigment is excellent, the writing quality is excellent, and the outflow of ink from the pen tip during writing is stable. To provide an ink.

[0004]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, the aqueous pigment ink containing two or more pigments and a water-soluble polymer has a viscosity of 50 to 20.
It has been found that the above object is solved by adjusting the pressure to 00 mPa · s and adding an alkylene oxide adduct of a polyhydric alcohol, thereby completing the present invention.

[0005] The aqueous pigment ink for ballpoint pens of the present invention comprises:
It comprises adding an alkylene oxide adduct of a polyhydric alcohol to an ink containing two or more kinds of pigments, water, a water-soluble polymer and a water-soluble organic solvent and having a viscosity of 50 to 2000 mPa · s. Preferably, the alkylene oxide adduct of the polyhydric alcohol is 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. More preferably, the alkylene oxide adduct of the polyhydric alcohol is an ethylene oxide adduct of diglycerin.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The alkylene oxide adduct of a polyhydric alcohol used in the ink of the present invention is glycerin,
Polyhydric alcohols such as trimethylolpropane or condensates thereof are added with alkylene oxides such as ethylene oxide and propylene oxide.The types of polyhydric alcohols and alkylene oxides, and the amount of alkylene oxide added constitute the pigment ink. Is appropriately selected depending on the components to be used.

The type of the water-soluble polymer used in the pigment ink of the present invention is not particularly limited as long as it has sufficient solubility in water and a water-soluble organic solvent in the ink. . More specifically, synthetic polymers such as polyvinylpyrrolidone and polyethylene glycol, natural polymers such as xanthan gum, guar gum, and hydroxyethyl cellulose, and derivatives thereof, and the like can be mentioned. Further, there are polyacrylic acid, acrylic acid copolymer, maleic acid resin and the like, specifically, acrylic resin,
A water-soluble resin such as a styrene acrylic resin or a styrene maleic acid resin in the form of a salt is used. Representative examples of the alkali metal forming a salt include sodium and potassium, and examples of the amine include aliphatic primary to tertiary amines such as mono-, di- or tri-methylamine;
Representative examples include alcohol amines such as mono-, di- or tri-propanolamine, methylethanolamine, methylpropanolamine, and dimethylethanolamine, ammonia, morpholine, and N-methylphorin. The content is 0.1 to 10% by weight in the total ink
Preferably it is 0.1 to 1.0% by weight.

The type of pigment used in the pigment ink of the present invention is not particularly limited, and any of inorganic and organic pigments commonly used in conventional aqueous pigment inks can be used. Examples of inorganic pigments include, for example, titanium oxide, carbon black, and metal powder, and examples of organic pigments include, for example, azo lake,
Examples include insoluble azo pigments, chelated azo pigments, phthalocyanine pigments, perylene and penoline pigments, anthraquinone pigments, quinacridone pigments, dye lakes, nitro pigments, nitroso pigments and the like. These pigments are used in combination of two or more in accordance with the intended hue. The content is selected in the range of usually 2 to 30% by weight, preferably 5 to 15% by weight based on the total amount of the ink. In the present invention, the combination of two or more types refers to a combination of a phthalocyanine-based pigment and an azo-based pigment, carbon black and a phthalocyanine-based pigment, a red pigment and a yellow pigment, a blue pigment and a yellow pigment, and a property, molecular structure, or hue pigment. Say.

Specific examples of the water-soluble organic solvent used in the ink of the present invention include ethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, 1,2-propanediol, and 1,3.
-Propanediol, 1,2-butanediol, 2,3
-Butanediol, 1,3-butanediol, 1,4-
Butanediol, 1,2-pentanediol, 1,5-
Pentanediol, 2,5-hexanediol, 3-methyl-1,3-butanediol, 2methylpentane-2,
4-diol, 3-methylpentane-1,3,5 triol, 1,2,3-hexanetriol, alkylene glycols such as glycerin, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, glycerol, diglycerol, tri Glycerols such as glycerol, lower alkyl ethers of glycols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, thiodiethanol, N-methyl-
2-pyrrolidone, 1,3-dimethyl-2-imidaridinone, and the like. Its content is preferably 40% by weight or less, more preferably 5 to 30% by weight based on the total amount of the ink.
% By weight.

In addition to the above, the pigment ink of the present invention may contain, if necessary, a preservative such as potassium linoleate, sodium ricinoleate or potassium oleate as a lubricant, or phenol or sodium benzoate as a preservative. As benzotriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, etc., triethanolamine as a pH adjuster,
Ammonia and the like can be contained.

[0011]

The pigment ink of the present invention has a storage stability of the ink,
Excellent in sharpness of written lines. Although the detailed mechanism of action is not clear, it is speculated that the dispersion stability of the pigment was improved by the action of the alkylene oxide adduct of the polyhydric alcohol used in the present invention. As a result, even for inks that are toned by two or more different types of pigments and that have been subjected to viscosity adjustment with a water-soluble polymer, pigment aggregation and sedimentation are likely to occur, stable writing properties are maintained over a long period of time. can get.

[0012]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the performance test in each example followed the following method. Bleeding: The degree of bleeding of the characters drawn on the writing paper was visually determined. ：: Does not bleed. Δ: Slight bleeding. X: Bleed. Writing feeling: Writing was performed with a ballpoint pen using a writing tester, and the outflow state of the ink was evaluated according to the following criteria. ：: Writing can be performed smoothly. Δ: Slightly caught. X: Sharp. Anti-boiling property: After writing with a mechanical writing tester at a speed of 4.5 m / min, an angle of 60 °, and a load of 100 g, observe the amount of ink adhering to the chip holder and the excess ink marks falling in the drawing line. The following criteria evaluated. ：: There is almost no dent. Δ: Slightly dented. ×: Many dents.

Anti-line-breaking property: Writing was performed with a writing tester using a ballpoint pen, and the drawing state was evaluated according to the following criteria. ：: good without line breaks. Δ: Somewhat broken. X: A line crack is conspicuous. Quick writeability: The ink following ability at the time of writing at twice the normal speed was evaluated according to the following criteria. ：: Writing can be performed well without blurring. Δ: Slightly lost. ×: Slightly larger. Drawing line drying property: “Helix” was written on writing paper in a constant temperature room at a temperature of 25 ° C. and a humidity of 65%, rubbed with a commercially available cotton swab after 10 seconds, observed for stains with ink, and evaluated according to the following criteria. ：: no dirt Δ: Slightly stained. ×: Stained.

[0014] Change with time: The pen body with the cap was left in an environment of 50 ° C, and the feasibility of writing and the change of writing taste were evaluated according to the following criteria. ：: No change from initial stage. Δ: Deterioration in writing condition such as deterioration of writing feeling, fading of drawing lines, and line breakage is observed. X: The writing state deteriorated remarkably, and it can be considered that writing was impossible. Drying resistance test (cap-off property): The pen body with the cap removed was allowed to stand at room temperature, and one week later, handwriting was evaluated by handwriting, and the following criteria were used to evaluate the possibility of writing. ：: Writing is possible without blurring from the beginning. Δ: 1 to several laps, but recovery is possible. X: The blur is remarkable and does not return during the test.

Example 1 Carbon black pigment (furnace type) 1% Blue pigment (phthalocyanine) 8% Glycerin 20% Ethylene oxide 15 mol adduct of glycerin 5% Ammonium polyacrylate 0.5% Phenol 0.1 % Potassium oleate 1% Deionized water Remaining total 100%

Example 2 Green pigment (phthalocyanine) 6.5% Yellow pigment (azo) 1.5% Ethylene glycol 25.0% Propylene glycol 8 mol adduct of trimethylolpropane 7.0% Xanthan gum 0 0.3% Phenol 0.1% Sodium ricinoleate 0.5% Deionized water Remaining total 100%

[Example 3] Red pigment (azo type) 6.0% Yellow pigment (azo type) 2.0% Propylene glycol 30.0% Diglycerin ethylene glycol 13 mol adduct 5.0% Guar gum 0.0 5% Phenol 0.1% Potassium linoleate 1.0% Deionized water Remaining total 100%

Comparative Example 1 The procedure of Example 1 was repeated, except that the glycerin ethylene oxide adduct was changed to glycerin.

Comparative Example 2 The procedure of Example 2 was repeated except that the propylene glycol adduct of trimethylolpropane was changed to glycerin.

Comparative Example 3 The procedure of Example 3 was repeated except that the ethylene glycol adduct of diglycerin was changed to ethylene glycol.

[0021]

[Table 1]

[0022]

The water-based pigment ink of the present invention has excellent pigment dispersion stability and writing taste, and has excellent temporal stability. In particular, inks in which the hue was adjusted by mixing two or more different kinds of pigments such as bull black, green, etc., conventionally, had a problem that the pigments agglomerated and deteriorated with time. Such a problem does not occur in the aqueous pigment ink.

Claims (4)

[Claims] 1. An alkylene oxide adduct of a polyhydric alcohol is added to an ink containing two or more kinds of pigments, water, a water-soluble polymer and a water-soluble organic solvent and having a viscosity of 50 to 2000 mPa · s. Aqueous pigment ink for ballpoint pens. 2. The alkylene oxide adduct of a polyhydric alcohol is 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. Item 1
A water-based pigment ink for a ballpoint pen according to the above. 3. The aqueous pigment ink for a ballpoint pen according to claim 1, wherein the alkylene oxide adduct of the polyhydric alcohol is an ethylene oxide adduct of diglycerin. 4. The aqueous pigment ink for a ball-point pen according to claim 1, wherein the pigment comprises a black pigment and a blue pigment.