JPH07247459A - Pigment ink composition for aqueous ball point pen - Google Patents

Abstract

PURPOSE:To obtain the subject ink composition containing sulfolane, a pigment, a dispersant and water, excellent in smoothness and smooth touch in writing and capable of drawing a line reduced in blur while preventing abrasion of a ball holder of a chip. CONSTITUTION:This ink composition contains (A) sulfolane, (B) a pigment, (C) a dispersant (preferably a water-soluble polymer such as a polyacrylic acid salt) and (D) water preferably in a ratio of 0.5 to 3wt.% component (A), 5 to 15wt.% component (B), 0.1 to 10wt.% component (C) and 40 to 90wt.% component (D), respectively based on the whole composition. In addition, the component (A) may be used recommendably in the form of a mixture with a water-soluble organic solvent such as ethylene glycol capable of improving non-drying properties of the ink composition. In that case, the content of the water-soluble organic solvent is preferably 5 to 40wt.% based on the whole composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment ink composition for water-based ballpoint pens, and more specifically, it has good lubricity, reduces wear of the ball holder of the tip, and has excellent writing feeling and smoothness. The present invention relates to an ink composition for a water-based ballpoint pen, which has characteristics such that a writing quality is obtained and a drawn line with less bleeding is provided.

[0002]

2. Description of the Related Art In a conventional aqueous pigment ink composition for a ballpoint pen using a pigment as a colorant, a polyhydric alcohol such as glycol or glycerin is used as a drying inhibitor for the ink composition in which the pigment is dispersed. A water-soluble high-boiling point organic solvent such as is used. However, when such a water-based pigment ink is used, the rotation of the ball during writing increases the frictional resistance between the ball of the chip and the ball holder, so that the ball seat is significantly worn and the writing feeling deteriorates. There is a problem that the outflow of ink becomes uneven due to deterioration of the ink. For the purpose of solving these problems, it has been attempted to add a lubricity improver such as unsaturated fatty acid or potassium oleate.

[0003]

With the above-mentioned conventional ink composition, sufficient lubricity cannot be obtained, and an unreadable phenomenon occurs due to abrasion of the ball seat, and even if sufficient lubricity is not obtained. Even if it is obtained, on the other hand, there is a problem in practical use that the surface tension of the ink is remarkably lowered, and the handwriting is apt to bleed.

The present invention was created in order to solve the above-mentioned problems of the prior art. It has excellent lubricity, and smooth ball rotation reduces wear of the tip holder seat, resulting in smoothness. It is an object of the present invention to provide a water-based pigment ink composition for a ball-point pen, which provides excellent writing quality and is excellent in non-drying property.

[0005]

As a result of various studies to solve the above problems, the present inventors have found that the above object can be achieved by incorporating sulfolane in the water-based pigment ink. The present invention has been completed based on the findings.

That is, the aqueous pigment ink composition for a ball-point pen of the present invention is characterized by containing sulfolane, a pigment, a dispersant and water. Here, the content of sulfolane is preferably 0.1 to 5% by weight, and more preferably 0.5 to 3% by weight, based on the total amount of the composition. If less than 0.1% by weight, sufficient lubricity cannot be obtained,
It is not possible to expect an improvement in writing performance, and it is 5% by weight.
If it exceeds, it is not suitable because the drawn line is easily blurred.

In the ink composition of the present invention, sulfolane may be used as a mixture with a water-soluble organic solvent. Examples of the solvent include water-soluble polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin, cellosolves such as ethylene glycol monomethyl ether (methyl cellsolve), ethylene glycol monoethyl ether (ethyl cellosolve), and diethylene glycol monomethyl ether ( Examples thereof include carbitols such as methyl carbitol) and diethylene glycol monoethyl ether (ethyl carbitol), glycol ether esters such as ethylene glycol monoethyl ether acetate.

The water-soluble organic solvent improves the non-dry property of the ink composition. Further, the content of the water-soluble organic solvent is appropriately selected usually in the range of 40% by weight or less, preferably 5 to 40% by weight based on the total amount of the composition.

The type of pigment used in the ink composition of the present invention is not particularly limited, and any pigment selected from inorganic and organic pigments conventionally used in conventional aqueous pigment ink compositions is used. can do. The inorganic pigments include, for example, titanium oxide, carbon black, metal powder, and the like, and the organic pigments include, for example, azo lake, insoluble azo pigment, chelate azo pigment, phthalocyanine pigment, perylene and perinone pigment, anthraquinone pigment, quinacridone pigment. , Dye lakes, nitro pigments, nitroso pigments and the like.

Specifically, phthalocyanine blue (C.
I. 74160), phthalocyanine green (C.I.
74260), Hansa Yellow 3G (C.I. 1167)
0), disazo yellow GR (C.I. 21100), permanent red 4R (C.I. 12335), brilliant carmine 6B (C.I. 15850), quinacridone red (C.I. 46500) and the like can be used.
These pigments may be used alone or in combination of two or more, and the content thereof is usually 2 to 30% by weight, preferably 5 to 5% by weight based on the total amount of the composition.
It is selected in the range of 15% by weight.

The dispersant in the composition of the present invention is used to disperse the pigment in water by adsorbing it on the surface of the pigment particles. Examples of the dispersant include nonionic, anionic surfactants and water-soluble polymers, and water-soluble polymers are preferably used.

Examples of nonionic surfactants include polyoxyalkylene higher fatty acid esters, higher fatty acid partial esters of polyhydric alcohols, higher fatty acid esters of sugars, and the like. Specifically, fatty acid esters of glycerin and polyglycerin fatty acid esters. , Propylene glycol fatty acid ester, pentaerythritol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbite fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene phytosterol, poly Oxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene castor , Polyoxyethylene lanolin, polyoxyethylene lanolin alcohols, polyoxyethylene alkyl amines, polyoxyethylene fatty acid amide, a polyoxyethylene alkyl phenyl formaldehyde condensate.

Examples of the anionic surfactant include alkylated sulfonates of higher fatty acid amides and alkylallyl sulfonates, and specifically, alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-
Acyl amino acid salts, N-acyl methyl taurine salts, polyoxyethylene alkyl ether acetates, alkyl phosphates, polyoxyethylene alkyl ether salts, and the like.

Examples of the water-soluble polymer include polyacrylic acid salts, styrene-acrylic acid copolymer salts, styrene-maleic acid copolymer salts, vinylnaphthalene-maleic acid copolymer salts, and β-naphthalene sulfone. There are anionic polymers such as acid formalin condensate and nonionic polymers such as polyvinyl alcohol, polyvinylpyrrolidone and polyethylene glycol.

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, mono-, di- or Examples thereof include alcohol amines such as tri-propanolamine, methylethanolamine, methylpropanolamine, and dimethylethanolamine, ammonia, morpholine, and N-methylpholine. The content of the dispersant is preferably 0.1 to 10% by weight based on the total amount of the composition.

The content of water used in the composition of the present invention is not particularly limited, but 40 to 90% by weight based on the total amount of the composition.
It is desirable to be used in the range of.

In addition to the above, a lubricant, an antiseptic, a rust preventive, a pH adjuster and the like may be added to the ink composition, if necessary. Examples of the lubricant include fatty acid salts such as potassium linoleate, sodium ricinoleate, potassium oleate, and sodium oleate.

Preservatives include phenol, isopropylmethylphenol, sodium pentachlorophenol, benzoic acid, sodium benzoate, dehydroacetic acid, sodium dehydroacetate, sorbic acid, potassium sorbate, 2-pyridinethiol-1-oxide sodium salt. , 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2
-4-Thiasozolylbenzimidazole, paraoxybenzoic acid ester and the like can be mentioned.

Examples of the rust preventives include tolyltriazole, benzotriazole and its derivatives, octyl phosphate, fatty acid phosphorus derivatives such as dioctyl thiophosphate, octyloxymethanephosphonic acid, dicyclohexylammonium nitrite, diisopropylammonium nitrite, and diisopropylammonium nitrite. Alkyl thiourea etc. are mentioned.

Examples of the pH adjusting agent include triethanolamine, monoethanolamine, diethanolamine and ammonia.

[0021]

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The inks of the examples and comparative examples were mixed with a stirrer for 3 hours, and then mixed with a sand mill.
It was obtained by dispersing for a time and further removing coarse particles by a centrifuge.

The inks obtained in the respective examples and comparative examples were evaluated by the judgment of the following writing test. The results are shown in Table 1. The ball sinking measurement method, the writing feeling, and the bleeding state of the handwriting in the written test are as follows. In addition, in the writing test, a batting type water-based ballpoint pen for occluding the ink in the batting and a direct liquid type water-based ballpoint pen having an ink tank for storing directly were used. The ball diameter of the ballpoint pen is 0.5 mm.

The tip used in Example 1 is a nickel-white tip, and the ball of the water-based ballpoint pen is a superhard ball. On the other hand, the tip used in Example 2 is a stainless tip, and the ball of the water-based ballpoint pen is a superhard ball.

Ball sinking: Using a spiral writing tester, a writing angle of 60 °, a writing speed of 4.0 m / min, and a load of 100 g, the depth of wear of the seat of the ball after 500 m, that is, of the ball protruding from the holder. The reduced length of the overhang was measured.

Writing feeling: A spiral having a height of about 1.5 cm is written 10 times, and the writing quality is judged according to the following criteria. ○ Smooth and stable writing quality △ Rugged and hard writing quality × Rugged and hard writing quality, with line breaks and directionality.

Bleeding of handwriting: 1 spiral of about 1.5 cm in height
Writing 0 circles, the degree of blurring of handwriting is determined based on the following criteria. ○ Clear handwriting without bleeding △ Blurred and unclear writing × Extremely unclear writing with marked bleeding

Example 1 A black water-based ballpoint pen pigment ink was prepared with the following composition. Carbon black MA100 (manufactured by Mitsubishi Kasei Co., Ltd.) 8.0% by weight Glycerin 20.0% by weight Ammonium salt of styrene acrylic acid resin 3.0% by weight Potassium oleate 0.5% by weight Triethanolamine 0.5% by weight Sulfolane 0.5 wt% Benzotriazole 0.1 wt% Phenol 0.1 wt% Purified water 67.3 wt% Total 100.0 wt%

Example 2 A blue water-based ballpoint pen pigment ink was prepared with the following formulation. Phthalocyanine blue (Chromofine Blue 4965 manufactured by Dainichiseika Co., Ltd.) 7.0% by weight glycerin 25.0% by weight Ammonium salt of styrene maleic acid resin 3.0% by weight potassium linoleate 0.5% by weight sulfolane 0.5% by weight % Triethanolamine 0.5 wt% Tolyltriazole 0.1 wt% Phenol 0.1 wt% Purified water 63.3 wt% Total 100.0 wt%

Comparative Example 1 A black aqueous pigment ink was prepared in the same manner as in Example 1 except that sulfolane was not used and purified water was 67.8% by weight.

Comparative Example 2 A blue water-based pigment ink was obtained in the same manner as in Example 2 except that sulfolane was not used and purified water was 63.8% by weight.

Comparative Example 3 A black aqueous pigment ink was obtained in the same manner as in Example 1 except that the added amount of sulfolane was 7% and the purified water was 60.8% by weight.

Table 1 shows the results of examining the ball sinking, the writing feeling, and the bleeding state of the handwriting in the writing test with the ballpoint pens using the inks obtained in Examples 1 and 2 and Comparative Examples 1 to 3.

[0033]

[Table 1]

As is clear from Table 1, in Examples 1 and 2 containing sulfolane, ink compositions having a small ball sinking, no handwriting bleeding, and a good writing feeling were obtained. Was given. On the other hand, in Comparative Examples 1 to 3 containing no sulfolane, no satisfactory ink composition was obtained.

[0035]

The pigment ink composition for a water-based ballpoint pen of the present invention has good lubricity when used in a ballpoint pen,
Prevents wear of the ball holder of the tip, gives a smooth writing feel, and gives a line with less bleeding.
It has excellent characteristics.

Claims (4)

[Claims] 1. An aqueous pigment ink composition for a ballpoint pen, which comprises sulfolane, a pigment, a dispersant, and water. 2. The aqueous pigment ink composition for a ballpoint pen according to claim 1, wherein the content of sulfolane is 0.1 to 5% by weight based on the total amount of the composition. 3. Sulfolane is added to the total amount of the composition of 0.
1-5% by weight, pigment 2-30% by weight, dispersant 0.1
10 to 10% by weight and 40 to 90% by weight of water.
The pigment ink composition for water-based ballpoint pens as described above. 4. The pigment ink composition for a water-based ballpoint pen according to claim 1, wherein the dispersant is a water-soluble polymer.