JP2000313836A - Water-based ink composition for fountain pen type writing utensil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide water-based ink compositions for fountain type writing utensils which do not cause writing failures such as blurs when left to stand for a long period of time with the cap removed and can obtain good handwriting. SOLUTION: A water-based ink composition for fountain pen type utensils is a water-based ink composition to be built in a fountain pen type writing utensil constituted in a manner capable of writing by mounting a pen point member which surrounds the tip of an ink lead core for guiding the ink in an axial barrel and has not less than three slits intersecting at the writing tip in the axial direction and comprises at least 0.1-7 wt.% colorant, 75-90 wt.% water, and 9-24 wt.% moisture retention organic solvent (to be selected from organic solvents having a surface tension at 20 deg.C of not lower than 40 mN/m, a viscosity of not higher than 25 mPa.s, and a vapor pressure of not higher than 1 mmHg) and shows a viscosity at 20 deg.C of not higher than 2 mPa.s and, at the same time, an ink viscosity, when the percent by weight of the moisture retention organic solvent in the ink composition comes to nearly the same percent by weight of the remaining water by the evaporation of water, of not higher than 5.5 mPa.s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-based ink composition for a fountain pen. More specifically, the present invention relates to a water-based ink composition which is used by filling a fountain pen-type writing instrument equipped with a pen point member provided with three or more slits surrounding the tip of an ink guide core and intersecting at the writing tip in the axial direction.

[0002]

2. Description of the Related Art Conventionally, a fountain pen type marking pen using a fountain pen type pen tip provided with an axial slit in a tapered plate piece has been disclosed, but the usability of the marking pen has not been satisfied. Was. In order to solve the above-mentioned problem, there has been disclosed a fountain pen type writing implement having a pen point member having a reduced directionality by providing an axial slit in a tapered cylindrical body (Japanese Utility Model Application Laid-Open No. 60-9).
1469, JP-A-10-35173, etc.).
The pen point member having the above-mentioned configuration communicates with the ink in the barrel to improve the ink output, and a guide core for leading out the ink is closely arranged in the slit of the pen point member. Therefore, the ink drawn out of the guide core and accumulated in the slit is easily exposed to the outside air and easily dried, and the ink in the guide core is also easily dried, and when left with the cap removed, water in the ink composition is reduced. Evaporation increases the concentration of the non-volatile solvent, colorant, and the like, increases the viscosity of the ink, and does not discharge well. Therefore, even if it is possible to add a small amount of a moisturizing organic solvent to the ink composition to suppress the viscosity increase in a short period of time and satisfy the drying resistance, the water evaporates significantly when left for a long period of time, Handwriting is faded or unwritable. Although the above-mentioned phenomenon becomes possible to write again when the cap is left in place, a drawback occurs in that the effective writing distance is shortened. Further, it is possible to suppress the evaporation of water by adding a large amount of the moisturizing organic solvent, but often the viscosity of the moisturizing organic solvent itself is high, the writing tip is exposed for a short time and slightly Evaporation of water also causes a marked increase in ink viscosity, which tends to make the handwriting faint or impossible to write. Accordingly, an ink composition satisfying the drying resistance, which is filled in the fountain pen type writing implement, has not been obtained.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a water-based ink composition suitably used for the above-mentioned fountain pen-type writing instrument, which causes writing defects such as blurring even when left for a long period of time with the cap removed. An object of the present invention is to provide a water-based ink composition for a fountain pen type writing instrument.

[0004]

SUMMARY OF THE INVENTION The present inventor has set the initial ink viscosity at 2 mPa · s (20 ° C.) or less so that good ink can be discharged from the writing tip. In addition to obtaining a satisfactory writing distance even if left unattended, the concentration of the organic solvent in the ink composition increases, causing an excessive increase in viscosity, or the relative solid content concentration increases due to evaporation of water. As a result of intensive studies on ink compositions that do not become unwritable due to solids such as colorants causing clogging in the ink guide core,
A surface tension at 20 ° C. is 40 mN / m or more, a viscosity is 25 mPa · s or less, and a predetermined amount of a moisturizing organic solvent having a vapor pressure of 1 mmHg or less is contained. It has been found that it is effective if the viscosity of the ink composition when the remaining water becomes approximately the same weight% is 5.5 mPa · s or less.

That is, according to the present invention, the leading end of the ink guide core for leading out the ink in the barrel is surrounded by the leading end of the writing guide.
A water-based ink composition incorporated in a fountain pen type writing implement configured to be writable by mounting a pen point member provided with at least one slit in the axial direction, wherein the ink composition is 0.1 to 7% by weight. A colorant, 75 to 90% by weight of water, 9
To 24% by weight of a moisturizing organic solvent (provided that the surface tension at 20 ° C. is 40 mN / m or more and the viscosity is 25 mP
a.s or less, selected from organic solvents having a vapor pressure of 1 mmHg or less), a viscosity at 20 ° C. of 2 mPa · s or less, and the moisture retaining organic solvent ink by evaporation of water. The requirement is an aqueous ink composition for a fountain pen-type writing instrument having an ink viscosity of 5.5 mPa · s or less when the weight% in the composition is substantially the same as the remaining water by weight. Furthermore, it is required that the moisturizing organic solvent is ethylene glycol, that the moisturizing organic solvent is ethylene glycol as a main organic solvent, and that 2-pyrrolidone and / or dimethyl sulfoxide are used in combination.

The ink composition has an initial ink viscosity of 4
If it is less than mPa · s, a composition that does not fade even when writing at a normal writing speed can be obtained, but by adjusting it to 2 mPa · s or less, it is excellent in ink follow-up during initial writing, and excessive writing pressure A good handwriting can be drawn without adding ink, and a composition that the ink can follow even when the writing speed is increased is obtained.

Further, the present invention is directed to an ink which can be used even if the water content of the ink composition becomes substantially the same as that of water by weight, since a large amount of water evaporates from the writing tip over time with the cap removed. It is an ink composition whose viscosity is unlikely to increase. As described above, in order to be able to write well even if left for several hours in a state where the writing tip is exposed to the outside, the problem is solved by adding a small amount of a moisturizing organic solvent. If left for a period of time, for example, several days, the handwriting becomes faint or unwritable due to evaporation of water. If the cap is left in this state, writing becomes possible again, but the writing distance is shortened. In addition, when a large amount of a moisturizing organic solvent is added, the initial viscosity becomes high, and even if a small amount of water evaporates, the ink composition becomes highly viscous and ink is easily clogged. Therefore, in the present invention, 9 to 24% by weight of a moisturizing organic solvent having a surface tension at 20 ° C. of 40 mN / m or more, a viscosity of 25 mPa · s or less, and a vapor pressure of 1 mmHg or less in the ink composition. Accordingly, an object of the present invention is to obtain an ink composition that satisfies the initial and long-term drying resistance and the effective writing distance. Since the moisture retaining organic solvent is supplied with water from the ink in the barrel through the ink guide core, it is possible to keep approximately the same weight% of moisture for a considerable period of time. Therefore, even if moisture evaporates from the ink composition at the writing tip, the ink viscosity when at least approximately the same weight percent of water as the organic solvent remains remains 5.5 mPa · s.
If s or less is satisfied, long-term drying resistance is satisfied, and good handwriting is obtained. Even when the ink at the tip of the writing part has a high viscosity, the ink viscosity at the tip part gradually decreases because the low-viscosity ink is supplied via the ink guide core when the writing starts. If the ink viscosity exceeds 5.5 mPa · s, it becomes difficult to discharge the ink from the gap between the pen tip pieces, and the handwriting is blurred at the time of starting writing. Also,
If the writing load is excessively applied to obtain a good handwriting in this state, the pen tip may be curved and the handwriting width may not be constant or may be damaged.

As the moisturizing organic solvent, ethylene glycol is preferably used. In addition to using ethylene glycol alone, ethylene glycol is used as a main solvent.
2-pyrrolidone or dimethyl sulfoxide can be used in combination. Other conventional moisturizing organic solvents can also be added in a range that does not impair the appropriate ink viscosity, glycerin, triethanolamine, diethylene glycol, hexylene glycol, thiodiethylene glycol, 1,3-butanediol, neoprene glycol,
Examples include polyethylene glycol, propylene glycol, butylene glycol and the like. Also, a small amount of the following organic solvents can be added, ethanol, propanol, butanol, sorbitol, diethanolamine,
Monoethanolamine, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether diethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, sulfolane, N-methyl-2-pyrrolidone, etc. Is mentioned.

As the colorant, a dye or a pigment is used, and preferably, a dye is used. As the dye,
Acid dyes, basic dyes and direct dyes can be used. Examples of the acid dye include Newcoccin (CI.16).
255), Tartrazine (CI. 19140), Acid Blue Black 10B (CI. 20470), Guinea Green (CI. 42085), Brilliant Blue FCF (CI. 42090), Acid Violet 6BN (C. I. 43525), Soluble Blue (C.I. 42755), Naphthalene Green (C.I.
I. 44025), eosin (CI. 45380),
Phloxine (CI. 45410), Erythrosin (CI. 45430), Nigrosine (CI. 504)
20), acid flavin (CI. 56205) and the like.

As the basic dye, chrysoidin (C.I.
I. 11270), methyl violet FN (CI.
42535), crystal violet (C.I.42)
555), malachite green (CI. 4200)
0), Victoria Blue FB (CI.44045),
Rhodamine B (CI. 45170), Acridine Orange NS (CI. 46005), Methylene Blue B
(CI. 52015) and the like are used.

As a direct dye, Congo Red (C.I.
I. 22120) Direct Sky Blue 5B (CI. 24400) Violet BB (CI. 27905) Direct Deep Black EX (CI. 3023)
5) Kayalas Black G Conch (CI. 35225) Direct Fast Black G (CI. 35255) Phthalocyanine blue (CI. 74180) or the like is used.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine blue, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as water that is already finely and stably dispersed in an aqueous medium using a surfactant. Dispersed pigment products and the like are used. I. Pigment 15: 3B [Product name: Sundai Super Blue GLL, pigment content 24%, Sanyo Dyeing Co., Ltd.] C.I. I. Pigment Red 146 [Product name: Sundai Super Pink FBL, pigment content 21.5
%, Sanyo Dyeing Co., Ltd.] C.I. I. Pigment Yellow 81 [Product name:
TC Yellow FG, pigment content: about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.] As the fluorescent pigment, a fluorescent pigment in the form of fine particles of a synthetic resin in which various fluorescent dyes are made into a solid solution in a resin matrix can be used. Other examples include pearl pigments, gold and silver metallic pigments, luminous pigments, white pigments such as titanium dioxide used for correction pens, metal powders such as aluminum, and fragrance or fragrance capsule pigments.

The colorants may be used alone or in admixture of two or more, and are used in the ink composition in the range of 0.1 to 7% by weight, preferably 0.3 to 4% by weight.

In addition, if necessary, a water-soluble resin, a pH adjuster, a rust preventive, a preservative or a fungicide lubricant can be added within the above-mentioned viscosity range. Examples of the water-soluble resin include an alkyd resin, an acrylic resin, a styrene-maleic acid copolymer, a cellulose derivative, polyvinyl pyrrolidone, polyvinyl alcohol, and dextrin. Examples of the pH adjuster include inorganic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide, and sodium acetate; and organic basic compounds such as water-soluble amine compounds such as diethanolamine and triethanolamine. Examples of the rust preventive include benzotriazole and its derivatives, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, sodium thiosulfate, ethylenediaminetetraacetate, saponin, dialkylthiourea and the like. Examples of the preservative or fungicide include sodium salt of carboxylate, 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate,
3,5,6-tetrachloro-4- (methylsulfonyl) pyridine and the like. As the lubricant, metal soap, polyalkylene glycol, fatty acid ester,
Ethylene oxide addition type cationic activators, phosphoric acid activators, thiocarbamates, dimethyldithiocarbamates and the like can be mentioned. In addition, it is also possible to add a fluorine surfactant for improving the permeability of the solvent, a nonionic, anionic or cationic surfactant, and an antifoaming agent such as dimethylpolysiloxane.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The aqueous ink composition for a fountain pen-type writing instrument of the present invention is prepared by adding an appropriate additive to a vehicle comprising water and a moisturizing organic solvent when a colorant and an additive are blended. It is prepared by heating, stirring and dissolving or dispersing as required, and is used by filling in a fountain pen-shaped writing instrument.

[0016]

EXAMPLES The formulations of the water-based ink compositions for fountain pen type writing implements prepared in Examples 1 to 3 and Comparative Examples 1 to 5 are shown below. In addition, the numerical value of the compounding amount indicates parts by weight, and the ink viscosity
It measured at 0 degreeC using the EL type viscometer (Tokyo Keiki).

Example 1 Blue Dye (CI Direct Blue 87) 1.0 Ethylene glycol 12.0 Phosphate ester surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, manufactured by Zeneca Corporation] 3.3 Water 86.1 The initial viscosity of the ink composition was 1.5 mPa · s. Further, 74.1% by weight of water was prepared from the ink composition.
The viscosity upon evaporation was 4.7 mPa · s.

Example 2 Red Dye (CI Acid Red 73) 1.0 Ethylene glycol 12.0 Glycerin 3.0 Phosphate-based surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-Benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, Zeneca Corporation] Calcium carbonate 0.3 Water 83.1 The initial viscosity of the ink composition was 1.65 mPa · s. The viscosity when water was evaporated from the ink composition by 68.1% by weight was 5.0 mPa · s.

Example 3 Blue Dye (CI Direct Blue 87) 1.0 Ethylene glycol 18.0 Phosphate ester surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, manufactured by Zeneca Corporation] 0.3 water 80.1 The initial viscosity of the ink composition was 1.75 mPa · s. Further, the viscosity when 62.1% by weight of water was evaporated from the ink composition showed 4.5 mPa · s.

Comparative Example 1 Blue dye (CI Direct Blue 87) 1.0 Ethylene glycol 3.0 Phosphate ester surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, manufactured by Zeneca Corporation] 3.3 Water 95.1 The initial viscosity of the ink composition was 1.3 mPa · s. 92.1% by weight of water was prepared from the ink composition.
The viscosity upon evaporation was 8.1 mPa · s.

Comparative Example 2 Blue Dye (CI Direct Blue 87) 1.0 Ethylene glycol 5.0 Glycerin 1.0 Phosphate-based surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-Benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, Zeneca Corporation] Manufacture] Calcium 0.3 Water 92.1 The initial viscosity of the ink composition was 1.3 mPa · s. Also, 86.1% by weight of water was prepared from the ink composition.
The viscosity upon evaporation was 6.3 mPa · s.

Comparative Example 3 Blue dye (CI Direct Blue 87) 4.0 Ethylene glycol 12.0 Phosphate ester surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, manufactured by Zeneca Corporation] 3.3 Water 83.1 The initial viscosity of the ink composition was 1.75 mPa · s. In addition, the viscosity when 71.1% by weight of water was evaporated from the ink composition was 6.4 mPa · s.

Comparative Example 4 Blue Dye (CI Direct Blue 87) 1.0 Ethylene glycol 6.0 Glycerin 6.0 Phosphate ester surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-Benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, Zeneca Corporation] Calcium carbonate 0.3 Water 86.1 The initial viscosity of the ink composition was 1.5 mPa · s. Further, 74.1% by weight of water was prepared from the ink composition.
The viscosity upon evaporation was 6.0 mPa · s.

Comparative Example 5 Red Dye (CI Acid Red 73) 1.0 Ethylene glycol 6.0 Glycerin 12.0 Phosphate ester surfactant 0.1 [Lubricant, trade name: Plysurf AL, Daiichi Kogyo Seiyaku Co., Ltd.] Triethanolamine (PH preparation) 0.2 1,2-Benzisothiazolin-3-one solution 0.3 [Preservative [trade name: Proxel XL-2, Zeneca Corporation] Calcium 0.3 Water 80.1 The initial viscosity of the ink composition was 1.85 mPa · s. Further, the viscosity when 62.1% by weight of water was evaporated from the ink composition was 6.2 mPa · s.

The ink composition prepared in each of the above Examples and Comparative Examples is obtained by housing a fiber bundle ink occluding body in a barrel, and fitting a tail plug at a rear end of the barrel. A fountain pen-type writing instrument equipped with a pen point member provided with three or more slits intersecting at the writing tip in the axial direction, surrounding the tip of the ink guide core for leading out the ink in the shaft cylinder to the part, is filled with each of the 6 pieces. I made each book.

Drying resistance test With the cap of each of the fountain pen-type writing implements removed,
After being left for 15 hours and 2 days under conditions of 25 ° C. and 65% humidity, the handwriting was written on paper and the handwriting was visually observed. The results are shown in the table.

[0027]

[Table 1]

The results of the judgment in the table are shown below. Drying resistance test ：: Good handwriting similar to the initial handwriting is obtained. Δ: Good handwriting is obtained when left for 15 hours, but handwriting is blurred when left for 2 days. ：: The handwriting is blurred when left for 15 hours, and the handwriting is still blurred two days later. ×: The handwriting becomes faint when left for 15 hours, and writing becomes impossible when left for 2 days.

[0029]

As can be seen from the above-mentioned writing test results, the present invention fills a fountain pen type writing instrument in which water in the ink composition is liable to evaporate. It is possible to provide a water-based ink composition for a fountain pen-type writing instrument which does not cause poor writing and can obtain good handwriting.

Claims (3)

[Claims] 1. A fountain pen surrounding a tip of an ink guide core for leading out ink in a barrel and having a pen point member provided with three or more slits intersecting at a writing tip in an axial direction to enable writing. An aqueous ink composition contained in a type writing instrument, wherein the ink composition comprises 0.1 to 7% by weight of a colorant, 75 to 90% by weight of water, and 9 to 24% by weight.
Moisturizing organic solvent (provided that the surface tension at 20 ° C is 4
0 mN / m or more, a viscosity of 25 mPa · s or less, and a vapor pressure of 1 mmHg or less.)
Pa · s or less, and the viscosity of the ink when the weight% of the moisturizing organic solvent in the ink composition becomes substantially the same as the remaining water by evaporation of water is 5.5 mPa.
A water-based ink composition for a fountain pen-type writing instrument, wherein the composition is not more than s. 2. The aqueous ink composition for a fountain pen type writing instrument according to claim 1, wherein the moisturizing organic solvent is ethylene glycol. 3. The aqueous ink composition for a fountain pen type writing implement according to claim 2, wherein the moisturizing organic solvent comprises ethylene glycol as a main organic solvent, and is used in combination with 2-pyrrolidone and / or dimethyl sulfoxide.