JPH08239617A - Water-based ink composition for ballpoint pens - Google Patents

Abstract

PURPOSE: To obtain a water-base ballpoint ink compsn. which hardly dries at a pen point and gives written lines hardly blurring by compounding a colorant, water, a water-sol. polymer, and a sugar alcohol. CONSTITUTION: This water-base ink compsn. having a viscosity of 50-2,000cP is prepd. by mixing and stirring at least essential components comprising a colorant (a dye or a pigment), water, a compd. represented by the formula (wherein R1 is H or methyl; R2 is 10-30C alkyl; M is H, Na, Li, an amine, or ammonium; and m and n are each the content of the corresponding group, m being 40-98wt.% and n being 2-60wt.%) and/or its salt, and a sugar alcohol and optional components comprising various water-sol. org. solvents, a polymeric dispersant, and other additives.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink composition for a ballpoint pen containing at least a coloring material, water and a water-soluble polymer.

[0002]

2. Description of the Related Art Ink compositions for general writing instruments use dyes and / or pigments as coloring materials, dissolve and / or disperse these coloring materials in a solvent, and if necessary, adjust viscosity and fix. A water-soluble polymer or resin is added to improve the properties, a surfactant is added to improve the solubility or dispersion stability, and an antiseptic / antifungal agent is added. Here, the viscosity of the ink composition is important because it is closely related to the form of the writing instrument.

Ink having low viscosity is difficult to stably supply ink to the pen tip unless a special ink supply mechanism such as a valve structure is adopted. Therefore, the ink is generally held by a fiber bundle or the like. ing. It is difficult to understand the remaining amount of ink in such a writing instrument. On the other hand, since ink having a high viscosity to a certain extent can be held in a raw ink state on a pipe or the like, it can be stored in a transparent or translucent hollow container so that the remaining ink amount can be known.

In the raw ink type ballpoint pen as described above, the viscosity of the ink composition is generally adjusted by adding a water-soluble polymer. In the case of an aqueous ink composition containing water as a solvent for the ink composition, for example, natural gum arabic, tragacanth gum, guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, xanthene gum, Dextran, semi-synthetic methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium starch glycolate, sodium alginate, propylene glycol alginate, synthetic polyvinyl alcohol, One kind of water-soluble polymer such as polyvinylpyrrolidone, polyvinylmethyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, a copolymer of vinyl acetate and polyvinylpyrrolidone, an alkali metal salt of acrylic resin, or the like. It has been used as a mixture of seeds or more.

[0005]

A ball-point pen is one in which a ball to which ink is attached is rotated on a writing surface such as a paper surface and the ink attached to the ball is transferred to the writing surface. When the ink dries, the viscosity of the ink becomes too high, which hinders smooth rotation of the ball, and also increases the resistance of the ink as it passes through the ink passage of the pen tip, reducing the supply amount to the ball. The lines are uneven. When such a situation is extremely heavy, there occurs a phenomenon that writing cannot be done at all. Particularly in the case of an ink thickened with a water-soluble polymer, when the solvent in the ink evaporates, the ratio of the thickener increases, so that the viscosity remarkably increases. Since the amount of ink that exists around the ball and in the ball holding chamber is extremely small, the viscosity of the ink increases greatly at the pen tip with a slight evaporation of the water in the ink, and it is easy for the handwriting to blur. there were. In particular, when a pigment is used as a coloring material, the pigment agglomerates due to the evaporation of the solvent, which sometimes makes writing impossible. Conventionally, it is common to increase the amount of high-boiling point solvent added to prevent ink from drying, but it is not possible to completely prevent the nib from drying, and it also slows the drying of the handwriting, so the handwriting easily bleeds. There was also a problem.

[0006]

That is, the present invention provides an aqueous ink for ball-point pens which comprises at least a coloring material, water, a compound represented by the following general formula (Formula 2) and / or a salt thereof, and a sugar alcohol. The subject matter is a composition.

[0007]

Embedded image

The water-based ink composition of the present invention, particularly when used as an ink composition for a water-based ballpoint pen, has an ink viscosity of 50 to 2000 cps (less than 600 cp, an ELD type viscometer standard cone rotor 1 rpm manufactured by Tokimec Co., Ltd.).
Measured at 600 cp or more, ELD manufactured by Tokimec Co., Ltd.
Type viscometer ST type rotor measured at 20 rpm, temperature 25
It is desirable to set in the range of (° C). Ink viscosity is 5
If it is less than 0 cp, it becomes difficult to hold the ink in the hollow cylindrical body, and if it is more than 2000 cp, the ink discharge amount becomes small and the handwriting has a low density.

The water-based ink composition of the present invention can be used without limitation as a colorant with dyes and pigments conventionally used in water-based ink compositions. Specific examples thereof include dyes such as C. ． I. Direct black 17,
Ibid 19, ibid 22, ibid 32, ibid 38, ibid 51, ibid 71,
C. I. Direct erotic-4, 26, 44, 5
0 ,. Direct Red 1, the same 4, the same 23, the same 31, the same 37, the same 39, the same 75, the same 80, the same 81, the same 83, the same 2
25, 226, 227, C.I. I. Direct Bull-
1, 1, 15, 41, 71, 86, 87, 10
6, 108, 199), direct dyes such as C.I. I.
Acid Black 1, the same 2, the same 24, the same 26, the same 31,
52, 107, 109, 110, 119, 154, C.I. I. Acid Ero-1, ibid 7, ibid 17, ibid 19, ibid 23, ibid 25, ibid 29, ibid 38, ibid 42, ibid 4
9, the same 61, the same 72, the same 78, the same 110, the same 127, the same 135, the same 141, the same 142, C.I. I. Acid Red 8, the same 9, the same 14, the same 18, the same 26, the same 27, the same 35,
37, 51, 52, 57, 82, 83, 87, 92, 94, 111, 129, 13
1, 1, 138, 186, 249, 254, 26
5, 276, C.I. I. Acid Violet 15, the same 17, the same 49, C.I. I. Acid Bull-1, ibid 7, ibid 9, ibid 15, ibid 22, ibid 23, ibid 25, ibid 40, ibid 4
1, the same 43, the same 62, the same 78, the same 83, the same 90, the same 9
3, same 100, same 103, same 104, same 112, same 11
3, 158, C.I. I. Acid Green 3, Same 9, Same 16, Same 25, Same 27, C.I. I. Acid Orange 56
Acid dyes such as C.I. I. Food dyes such as hooddero-3, malachite green (CI.42000), Victoria Bull-FB (CI.44045), methyl violet FN (CI.42535), rhodamin F4.
G (C.I. 45160), Rhodamin 6GCP (C.I.
I. 45160) and the like.

Pigments are used as a coloring material for inks. For example, carbon black such as farnest black, contact black, thermal black and acetylene black, black iron oxide, yellow iron oxide, Red iron oxide, ultramarine, navy blue, cobalt bull-, titanium yellow-,
Inorganic pigments such as turquoise and molybdate orange, C.I.
I. PIGMENT RED 2, same 3, same 5, same 1
7, 22, 22, 38, 41, 48: 2, 48:
3, the same 49, the same 50: 1, the same 53: 1, the same 57: 1, the same 58: 2, the same 60, the same 63: 1, the same 63: 2, the same 64:
1, the same 88, the same 112, the same 122, the same 123, the same 14
4, ibid 146, ibid 149, ibid 166, ibid 168, ibid 17
0, 176, 178, 179, 180, 18
5, Same 245, Same 146, Same 170, Same 176, Same 17
7, 185, 190, 194, 206, 20
7, 209, 216, 245, C.I. I. PIGM
ENT ORANGE 5, 10, 10, 13, 16,
36, 40, 43, C.I. I. PIGMENT V
IOLET 19, 23, 31, 31, 33, 36,
38, 50, C.I. I. PIGMENT BLUE
2, ibid 15, ibid 15: 1, ibid 15: 2, ibid 15: 3, ibid 15: 5, ibid 16, ibid 17, ibid 22, ibid 2, ibid 2
5, the same 60, the same 66, C.I. I. PIGMENT BRO
WN 25, 26, C.I. I. PIGMENT YEL
LOW 1, the same 3, the same 12, the same 13, the same 24, the same 81,
93, 94, 95, 97, 99, 108,
Same 109, Same 110, Same 117, Same 120, Same 139,
153, 166, 167, 173, C.I. I. P
Examples include organic pigments such as IGMENT GREEN 7, 10, and 36, 9.10-dianilinoanthracene, those obtained by dissolving a fluorescent dye in a synthetic resin, those obtained by coloring a synthetic resin with a fluorescent dye, and metal powders.

Further, in the case of a pigment ink composition, an aqueous ink composition base in which a pigment is dispersed in an aqueous medium can be used. Specifically, Fuji. S
P series, Emacol series manufactured by Sanyo Pigment Co., Ltd.,
Sandye series, M manufactured by Orient Chemical Industry Co., Ltd.
microPigmo series, MicroJet series, Rio. Fast series, Nippon Fluorescent Chemical Co., Ltd. NKW series, Toyo Soda Co., Ltd.
Cosmo Color Series manufactured by Shin Loi Co., Ltd., Shin Loihi Color Base Series manufactured by Shin Loi Co., Ltd., and the like. These can be used alone or in combination of two or more. Further, a dye, a pigment and a disperse pigment may be mixed and used.

Water is essential as the solvent, and various organic solvents can be used in addition to this. Specific examples of the organic solvent include ethanol, methanol, 1-propanol,
2-Propanol, 1,3-Propanediol, 2-Methyl-2,4-pentanediol, 2-Methoxyethanol, 2-Ethoxyethanol, 2-Butoxyethanol
2-phenoxyethanol, 2-benzyloxyethanol, 2- (2-methoxyethoxy) ethanol,
2- (2-ethoxyethoxy) ethanol, 2- (2-
Butoxyethoxy) ethanol, water-soluble organic solvents such as glycerin, ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol and the like can be mentioned.

As the resin for thickening the ink composition, the substance represented by the above general formula (Formula 2) and / or its salt can be used, and one kind or a mixture of two or more kinds can be used.

As the sugar alcohol, tetrite, pencit, xylit, hexit, inositol, maltitol, maltothritol, maltotetratole, maltopentatol, maltohexatol, maltoheptol and the like can be used, and one or more kinds thereof can be used. Can be mixed and used.

In the ink composition of the present invention, a coloring material which is an essential component, water, a substance represented by the general formula (Formula 2) and / or a salt thereof, and a sugar alcohol are mixed and stirred. Obtainable. Further, if necessary, it may be subjected to a disperser, and the coloring material may be classified by filtration, centrifugation, or the like.

In addition to the above essential components, various polymer dispersants, surfactants and water-soluble polymers can be used. For example,
As a polymer dispersant, natural rubbers such as gum arabic and tragacanth, glucosides such as saponin, lignin sulfonate, natural polymers such as shellac, polyacrylate, styrene-acrylic acid copolymer salt, styrene -Anionic polymers such as salts of maleic acid copolymers, salts of vinylnaphthalene-maleic acid copolymers, salts of β-naphthalenesulfonic acid formalin condensates, phosphates, polyvinyl alcohol, polyvinylpyrrolidone And nonionic polymers such as polyethylene glycol. Further, as the surfactant, fatty acid salts, higher alcohol sulfate ester salts, liquid fatty acid sulfate ester salts, anionic surfactants such as alkylallyl sulfonates, polyoxyethylene alkyl ethers, sorbitan alkyl esters , Nonionic surfactants such as polyoxyethylene sorbitan alkyl esters. Examples of the water-soluble polymer include natural gum arabic, tragacanth gum, guar gum and locust bead.
Gum, alginic acid, carrageenan, gelatin, casein, xanthene gum, dextran, semi-synthetic methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium starch glycolate, sodium alginate. Propylene glycol alginate, synthetic polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, vinyl acetate / polyvinylpyrrolidone copolymer, acrylic resin Examples thereof include alkali metal salts.

In order to prevent the ink passage of the writing instrument from being clogged with mildew and inhibiting the outflow of the ink composition, sodium dehydroacetate, 1,2-benzisothiazolin-3-one, sodium benzoate, morpholine, morpholine. An antiseptic / antifungal agent such as a derivative may be added as appropriate.

Further, in the case of a writing instrument in which a metal is used in a portion which comes into contact with the ink composition, a corrosion inhibitor such as benzotriazole or ethylenediaminetetraacetic acid salt is appropriately added to prevent corrosion of the metal. You can

Various known pH adjusters such as sodium hydroxide and triethanolamine may be added to the ink composition of the present invention. Particularly when the pH of the ink is in the range of 5.5 to 9, The stability of viscosity with time is further improved.

[0020]

The reason why the water-based ink composition for a ballpoint pen of the present invention does not easily dry even at the pen tip portion and hardly causes scraping even when the pen tip portion is exposed is considered as follows.

The substance represented by the above general formula (Formula 2) forms a microgel structure in the ink to increase the viscosity of the ink. However, when the solvent in the ink evaporates, the density of the microgel increases and the microgels are bound to each other. Form a film. Since this film is porous, the function of suppressing evaporation of the solvent is relatively weak, and the ink at the pen tip is dried.
However, when the sugar alcohol is present in the ink, the sugar alcohol is taken into the film formed by the substance represented by the general formula (Formula 2) to form a hygroscopic film. For this reason, the ink on the pen tip portion becomes difficult to dry. Also,
Since the formed film is brittle, it is easily broken by the force during writing, so that the ink is ejected immediately after writing, and it is possible to obtain handwriting without blurring.

[0022]

EXAMPLES The present invention will be described in detail below with reference to Examples. In Examples and Comparative Examples, "part" means "part by weight".
Indicates.

The conditions for measuring the viscosity of each ink composition are 50
Less than cp is measured with ELD type viscometer standard cone rotor 10 rpm manufactured by Tokimec Co., Ltd., 50 cp or more and 600 c
Less than p is measured with ELD type viscometer standard cone rotor 1 rpm manufactured by Tokimec Co., Ltd., 600 cp or more and 5500 c
Less than p is ELD type viscometer ST type low manufactured by Tokimec Co., Ltd.
Measured at 20 rpm. (Measuring temperature 25 ℃)

Example 1 Purified water 63.0 parts C.I. I. Direct Black 19 7.0 parts Ethylene glycol 10.0 parts 2% aqueous solution of PEMULEN TR-1 (compound represented by the general formula (Chemical Formula 2), manufactured by Good-rich Co., USA) 15.0 parts Xylit 5.0 parts After mixing the above components and stirring for 1 hour, a 25% aqueous sodium hydroxide solution (pH adjuster) was added to adjust the pH to 7.5 and filtration was performed to obtain a black ink having a viscosity of 800 cp. It was

Example 2 Purified water 75.75 parts C.I. I. Acid Red 87 5.0 parts C.I. I. Acid Orange 56, manufactured by Orient Chemical Industry Co., Ltd. 1.0 part Propylene glycol 10.0 part 1,2-benzisothiazolin-3-one 0.2 part PEMULEN TR-2 (the above general formula (formula 2)) 2% aqueous solution of the compound represented by the above-mentioned Good-rich Co., Ltd. in the United States 5.0 parts Guar gum 0.05 parts PO-500 (monosaccharide alcohol polysaccharide alcohol mixture, manufactured by Towa Chemical Industry Co., Ltd.) 3 0.0 parts Red ink having a viscosity of 200 cp was obtained by mixing the above components, heating to 40 to 50 ° C., stirring for 1 hour, adding a 25% aqueous sodium hydroxide solution to adjust the pH to 8.5, and filtering. Got

Example 3 Purified water 32.8 parts NKW-2105 (fluorescent aqueous ink base, manufactured by Nippon Fluorescent Chemical Co., Ltd.) 40.0 parts Ethylene glycol 10.0 parts Sodium dehydroacetate 0.2 parts AQPEC HV- 2% aqueous solution of 501 (compound represented by the general formula (Chemical Formula 2), manufactured by Sumitomo Seika Chemicals, Ltd.) 14.0 parts Maltitol 3.0 parts The above components are mixed and stirred for 1 hour. Ethanolamine (pH adjuster) was added to adjust the pH to 6.0 and the mixture was filtered to obtain a yellow fluorescent ink having a viscosity of 1300 cp.

Example 4 Purified water 65.4 parts Carbon black 8.0 parts Ethylene glycol 10.0 parts Styrene-acrylic acid copolymer ammonium salt 2.5 parts AQPEC HV-504 (the above general formula ( 2% aqueous solution of the compound represented by Chemical formula 2), manufactured by Sumitomo Seika Co., Ltd. 12.0 parts Guar gum 0.1 parts PO-20 (monosaccharide alcohol polysaccharide alcohol mixture, manufactured by Towa Chemical Industry Co., Ltd.) 2.0 parts Of the above components, except AQPEC HV-504 and guar gum are mixed and dispersed in a commercially available sand mill for 4 hours,
2 with AQPEC HV-504 and guar gum
After stirring for an hour, triethanolamine was added to adjust the pH to 7.
After adjusting to 5, coarse particles were removed by centrifugation to obtain a black ink having a viscosity of 1700 cp.

Comparative Example 1 66.0 parts of purified water C.I. I. Direct Black 19 7.0 parts Ethylene glycol 12.0 parts PEMULEN TR-1, 2% aqueous solution 15.0 parts After mixing the above components and stirring for 1 hour, 25% aqueous sodium hydroxide solution (pH adjuster) Was added to adjust the pH to 7.5 and filtered to obtain a black ink having a viscosity of 800 cp.

Comparative Example 2 Purified water 48.0 parts C.I. I. Direct Black 19 7.0 parts Ethylene glycol 30.0 parts PEMULEN TR-1, 2% aqueous solution 15.0 parts After mixing the above components and stirring for 1 hour, 25% aqueous sodium hydroxide solution (pH adjuster) Was added to adjust the pH to 7.5 and filtered to obtain a black ink having a viscosity of 800 cp.

Comparative Example 3 Purified water 67.4 parts Carbon black 8.0 parts Ethylene glycol 10.0 parts Styrene-acrylic acid copolymer ammonium salt 2.5 parts AQPEC HV-504, 2% aqueous solution 12 0.0 parts guar gum 0.1 part Among the above components, AQPEC HV-504 and other than guar gum were mixed and dispersed for 4 hours with a commercially available sand mill,
2 with AQPEC HV-504 and guar gum
After stirring for an hour, triethanolamine was added to adjust the pH to 7.
After adjusting to 5, coarse particles were removed by centrifugation to obtain a black ink having a viscosity of 1700 cp.

[0031]

【The invention's effect】

<Test 1> The inks of Examples 1 to 4 and Comparative Examples 1 to 3 were filled in a ballpoint pen K105 manufactured by Pentel Co., Ltd. (holding the ink in a transparent hollow container, ball diameter 0.5 mm), and the pen tip was exposed to the outside air. The exposed state was left laterally for 24 hours in an environment of a temperature of 50 ° C. and a humidity of 30%, and then writing was performed, and the length of a faint writing line from the start of writing to the appearance of ink was measured.

<Test 2> The inks of Examples 1 to 4 and Comparative Examples 1 to 3 were filled in a ball-point pen K105 manufactured by Pentel Co., Ltd., and the writing line width when writing on fine paper (grammage 70 kg) was measured with a tool microscope. (STM-C type, manufactured by Olympus Optical Co., Ltd.). The results of tests 1 and 2 are shown in Table 1.

[0033]

[Table 1]

As described above, when the ink of the present invention is assembled into a ball-point pen, the ink remaining amount can be confirmed.
Although it is a water-based ink having a viscosity capable of holding the ink in a transparent or semi-transparent container, it is possible to obtain a handwriting which is excellent in drying resistance with a pen tip and hardly bleeds.

Claims (1)

[Claims] 1. An aqueous ink composition for a ballpoint pen, which comprises at least a coloring material, water, a compound represented by the following general formula (Formula 1) and / or a salt thereof, and a sugar alcohol. Embedded image