JP2001342418A - Water-based ink for ball-point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ink for a ball-point pen, hardly causing blur after a long-term preservation and excellent in preservation stability. SOLUTION: This water-based ink for the ball-point pen contains a saccharified product of a reduced starch in combination with a resin emulsion having 40-80 deg.C minimum film-forming temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for a ball-point pen, and more particularly, to an ink for ball-point pens, such as a pen-tip retractable ball-point pen, which is preferably used for a ball-point pen having low airtightness with respect to a ball-point pen tip. The present invention relates to a stable water-based ink for ballpoint pens without deterioration.

[0002]

2. Description of the Related Art Conventionally, ballpoint pens can provide relatively fine handwriting and, due to abrasion and crushing of the pentip even when used for a long period of time, compared to writing instruments having a fibrous nib or a resin nib. Widely used because the change in handwriting width is small. The viscosity of the aqueous ink composition used for such a ballpoint pen is known to be one to several mPa · s (25 ° C.) and one to 50 to 2,000 mPa · s (25 ° C.). Those having 1 to several mPa · s (25 ° C.) are mainly used for ballpoint pens having a structure using batting as an ink occluding material, and 50 to 2,000 mPa · s (25 ° C.)
Are mainly used for those having a structure using a hollow cylinder as an ink reservoir.

In a writing mechanism of a ballpoint pen, ink attached to the ball surface is transferred to a writing surface such as paper as the ball rotates. Ballpoint pens are basically
It is necessary to satisfy the general requirements for ballpoint pens, in which an appropriate amount of ink is transferred to the surface to be written, and furthermore, blurring in handwriting and various problems such as ink leakage from the ballpoint tip of the ballpoint pen do not occur, Therefore, it is required to appropriately select additives and adjust physical properties.

[0004]

In particular, in the case of a pen tip retractable ballpoint pen, addition of a high-boiling organic solvent or addition of a humectant has been attempted in order to suppress the loss of ink. Ink loss from the slight gap between the ball and the tip of the ballpoint pen tip increases, the viscosity of the ink increases, the ink's ability to follow the ink during writing deteriorates, and the ink drops on the inside of the pen tip. When dried, the solidified product hinders the ejection of the ink, and is liable to cause problems such as blurring. Therefore, in the structure of the pen tip, by pressing the ball part from the rear end of the ball part with a spring or the like, the gap between the ball and the tip of the ballpoint pen tip which is crimped so that the ball cannot be removed is reduced, and the weight loss is suppressed. Although a product has been put on the market, a slight gap is inevitably generated, and a loss phenomenon of ink occurs because the loss of ink cannot be sufficiently suppressed.

[0005]

According to the present invention, water, a colorant, a reduced starch saccharified product, and a minimum film forming temperature of 40 ° C. to 80 ° C.
A water-based ink for a ball-point pen, characterized by containing at least a resin emulsion as described above.

The details will be described below. Minimum film formation temperature is 4
A resin emulsion at 0 ° C to 80 ° C is used as a water-soluble thickener to increase the viscosity of the entire ink and stabilize the dispersion by retaining the pigment, or to prevent ink leakage by lowering the fluidity of the ink. In addition, various troubles, such as smoothing the rotation of the ball and improving the writing feeling, are less likely to occur. When the minimum film forming temperature is lower than 40 ° C., the film is formed quickly at room temperature, so that the film is relatively formed to the inside of the pen tip over a long period of time, and the viscosity rises more than necessary, causing fuzziness. . Minimum film formation temperature is 80
If the temperature is higher than 0 ° C., a hard and brittle film is formed, and the broken film is involved in the inside of the ball during writing, causing clogging and scumming. Minimum film formation temperature is 40
Primal B-74 (minimum film-forming temperature: 41 ° C.), WL-5
1 (52 ° C), WL-71 (52 ° C), W
L-81 (57 ° C), WL-91 (52
° C), WL-93 (77 ° C), main coat TL
-5 (52 ° C), Experimental Emulsion E-1630 (53 ° C), E-357 (52 ° C)
° C) (Rohm and Haas Japan K.K.)
Acronal YJ-1100D (same as above: 58 ° C.)
(Above, manufactured by BASF Dispersion Co., Ltd.). Minimum film formation temperature is 40
The amount of the resin emulsion used is preferably from 0.1 to 5.0% by weight, based on the total amount of the water-based ink for a ballpoint pen. I can't get it.

The reduced starch saccharified substance is a substance obtained by reducing a special starch saccharified substance mainly composed of oligosaccharides, and is used to improve the stability of the ink after long-term storage. . The amount of the reduced starch saccharified product is preferably 0.1 to 10.0% by weight based on the total amount of the aqueous ink for a ballpoint pen. If the amount is small, no effect is obtained, and if it is large, no further effect is obtained. As an example of reduced starch saccharified product,
PO-20, PO-30, PO-40, PO-60, P
O-300, PO-500 (Towa Chemical Industry Co., Ltd.)
Manufactured).

As the coloring material, dyes and / or pigments can be used. As the dye, any of direct dyes, acid dyes, basic dyes and the like can be used, but depending on the type of the ball or chip material, if the pH is low, it may be corroded, so that the pH is neutral. It is preferable to use a direct dye and an acid dye which are stable in alkali and dissolve. An example is given below.

The direct dyes include C.I. I. Direct Black 17, 19, 22, 22, 32, 5
1, and 71, C.I. I. Direct Yellow 4, 26, 44, 50, C.I. I. Direct Red 1, Same 4, Same 23, Same 31, Same 37, Same 39, Same 75, Same 80, Same 8
1, 83, 225, 226, 227, C.I. I.
Direct Blue 1, 15, 15, 71, 86, 10
6, 199 and the like.

Examples of the acid dye include C.I. I. Acid Black 1, 2, 24, 26, 31, 31, 52, 1
07, 109, 110, 119, 154, C.I.
I. Acid Yellow 7: 1, 17, 17, 19, 23,
25, 29, 38, 42, 49, 72, 61, 78, 110, 141, 135, 12
7, 142, C.I. I. Acid Red 8, 9 and 1
4, 18, 18, 26, 35, 37, 5
1, 52, 57, 82, 87, 92, 9
4, 111, 129, 131, 138, 18
6, 249, 254, 265, 276, C.I.
I. Acid Violet 15, 17 and C.I. I. Acid Blue 1, 7, 9, 15, 22, 23,
25, 40, 41, 43, 62, 78, 83, 90, 93, 103, 112, 11
3, 158, C.I. I. Acid Green 3, 9, 16, 25, 27, and the like.

The basic dyes include C.I. I. Basic Blue 7, C.I. I. Basic Red 1 and the like.

As the pigment, conventionally known pigments can be used, and specific examples include Special Black 6,
S170, S610, 5, 5, 4, 4A, 55
0, 35, 250, 100, Printex 1
50T, U, V, 140U, 140V, 9
5, 90, 85, 80, 75, 55, 4
5, P, XE2, L6, L, 300, 3
# 0, # 3, # 35, # 25, # 200, #A, #G (all made by Degussa Japan KK), # 2400B, # 2
350, # 2300, # 2200B, # 1000, # 9
50, # 900, # 850, # MCF88, MA60
0, MA100, MA7, MA11, # 50, # 52,
# 45, # 44, # 40, # 33, # 32, # 30, C
F9, # 20B, # 4000B (Mitsubishi Chemical Industries, Ltd.), MONARCH 1300, 100, 1000, 900, 880, 800, 700,
MOGULL, REGAL 400R, 660R, 500R, 330R, 300R, 99R, ELF
TEX 8, 12 and BLACK PEARLS 20
00 (manufactured by Cabot Co. LTD, USA), Ra
ven 7000, 5750, 5250, 500
0, 3500, 2000, 1500, 125
5, 1250, 1200, 1170, 106
0, 1040, 1035, 1020, 100
0, 890H, 890, 850, 790, 7
80, 760, 500, 450, 430, 4
20, same 410, same 22, same 16, same 14, same 825o
il Beads, H20, C, Conducte
x 975, 900, SC (all above, Colombian
Carbon black, such as Carbon Japan Co., Ltd.), KA
-10, 10P, 15, 15, 20, 30, 35
60, 80, 90, KR-310, 380, 460, 480 (all manufactured by Titanium Industry Co., Ltd.), P2
5 (manufactured by Nippon Aerosil Co., Ltd.), etc., BS
-605, 607 (manufactured by Toyo Aluminum Co., Ltd.), Bronze Powder P-555, P-777 (manufactured by Nakajima Metal Foil Industry Co., Ltd.), Bronze Powder 3L5, 3
Metal powder pigments such as L7 (all manufactured by Fukuda Metal Foil Industry Co., Ltd.), inorganic pigments such as black iron oxide, yellow iron oxide, red iron oxide, ultramarine blue, navy blue, cobalt blue, chrome green, chromium oxide, etc. Hansa Yellow-10G, Same 5G, Same 3G, Same 4, Same GR, Same A, Benzidine Yellow, Permanent Yellow NCG, Tartrazine Lake, Quinoline Yellow, Sudan 1, Permanent Orange, Indaslen Brilliant Orange GN, Permanent Brown F
G, para brown, permanent red 4R, fire red, brilliant carmine BS, pyrazolone red, lake red C, quinacridone red, brilliant carmine 6B, bordeaux 5B, thioindigo red,
Fast violet B, dioxazine violet,
Organic pigments such as alkali blue lake, phthalocyanine blue, indigo, acid green lake, and phthalocyanine green are exemplified. In addition, inorganic fluorescent pigments such as zinc sulfide, zinc silicate, cadmium zinc sulfate, calcium sulfide, strontium sulfide, and calcium tungstate may be used. Coloring agents such as the above dyes and pigments can be used alone or in combination with other, and the amount used varies depending on the color tone and the like.
When the amount is small, the color development of the ink is poor, and when the amount is large, the colorant is insufficiently dispersed to cause various problems. Therefore, the amount is preferably 0.1 to 40% by weight based on the total amount of the water-based ink for a ballpoint pen.

When a pigment is used in the aqueous ink for a ballpoint pen, it is preferable to use a dispersant in combination. As the dispersant, a polymer dispersant generally used in the related art and a dispersant used as a pigment dispersant such as an anionic or nonionic surfactant can be used. As an example, as a polymer dispersant, gum arabic, natural gums such as tragacanth gum, glucosides such as saponin, methyl cellulose, carboxycellulose, cellulose derivatives such as hydroxymethyl cellulose, lignin sulfonate, natural polymers such as shellac, poly Anionic polymers such as acrylates, salts of styrene-acrylic acid copolymers, salts of vinylnaphthalene-maleic acid copolymers, sodium salts of β-naphthalenesulfonic acid formalin condensate, phosphates, etc., and polyvinyl chloride Examples include nonionic polymers such as alcohols and polyethylene glycols. As surfactants, alkyl sulfates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids and salts thereof, N-acylmethyl taurine salts, polyoxyethylene alkyl ether acetates, alkyl sulfocarboxylates, α- Anionic surfactants such as olefin sulfonates, alkyl phosphates and polyoxyethylene alkyl ether phosphates; nonionics such as polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polyoxyethylene sorbitan alkyl esters Surfactants. These water-soluble resins,
One or more water-soluble resins and surfactants are selected and used in combination. When the amount is small, the dispersing effect to be added is weak, and when the amount is large, there is a concern that the dissolution balance of each composition in the ink may be lost and various problems may occur. On the other hand, 0.1 to 10% by weight is preferable.

Further, the use of an aqueous ink base in which a pigment is dispersed in an aqueous medium is advantageous in producing a pigment ink. Specifically, Fuji SP Black 8
031, 8119, 8167, 8276, 83
81, 8406, 8556, 8922, Fuji
SP RED 5096, 5111, 5193,
5220, 5543, 5544, Fuji SP
Bordeaux 5500, Fuji SP Blu
e 6062, 6133, 6134, 6401,
Fuji SP Green 7051, Fuji S
P Yellow 4060, 4178, Fuji
SP Violet 9011, Fuji SP Pi
NK 9524, NK 9527, Fuji SP Ora
nge534, Fuji SP Brown 3074
(These are products of Fuji Dye Co., Ltd.), Emacol Blac
k CN, Emacol Blue FBB, FB,
Same KR, Emacol Green LXB, Emac
ol VioletBL, Emacol Brown
3101, Emacol Carmine FB, Em
acol RED BS, Emacol Orange
R, Emacol Yellow FD, IRN,
3601, FGN, GN, GG, F5G, F7G, FGN, 10GN, Sandy Super Bl
ack K, same C, Sandy Super Gre
y B, Sandye Super Brown S
B, FRL, RR, Sandy Super N
avy Blue HRL, GLL, HB, FB
LH, FBL-160, FBB, Sandye
Super Violet BL H / C, BL, BLN, Sandye Super Bordeaux
FR, Sandye Super Pink FB
L, F5B, Sandy SuperRubine
FR, Sandy Super Carmine
FB, Sandy Super Red FFG, RR, BS, Sandye Super Orange
e FL, R, BO, Sandye Gold Y
yellow 5GR, same R, same 3R, Sandye Y
yellow GG, F3R, IRC, FGN, GN, GRS, GSR-130, GSN-13
0, the same GSN, the same 10GN (above, Sanyo Dyeing Co., Ltd.)
Manufactured), Rio Fast Black Fx 801
2, 8313, 8169, Rio Fast Re
d Fx 8209, 8172, Rio Fast
Red S Fx 8315, 8316, Rio F
as Blue Fx 8170, Rio Fast
Blue Fx 8170, Rio Fast Bl
ue S Fx8312, Rio Fast Green
n S Fx 8314 (Toyo Ink Co., Ltd.)
NKW-2101, 2102, 2103, 2104, 2105, 2106, 2107, 2
108, 2117, 2127, 2137, 21
67, 2101P, 2102P, 2103P, 2104P, 2105P, 2106P, 2107
P, 2108P, 2117P, 2127P, 2
137P, 2167P, NKW-3002, 300
3, 3004, 3005, 3007, 307
7, 3008, 3402, 3404, 340
5, 3407, 3408, 3477, 360
2, 3603, 3604, 3605, 360
7, 3677, 3608, 3702, 370
3, 3704, 3705, 3777, 370
8, 6013, 6038, 6559 (all manufactured by Nippon Fluorescence Co., Ltd.), Cosmo Color S 1000F series (manufactured by Toyo Soda Co., Ltd.), Victoria Yellow G-1
1, G-20, Victoria Orange G-16, G
-21, Victoria Red G-19, G-22, Victoria Pink G-17, G-23, Victoria Green G-18, G-24, Victoria Blue G
-15, G-25 (all manufactured by Mikuni Pigment Co., Ltd.), Pollux Blue PC5T-1020, Pollux Black PC8T-135, Poluc Red IT-10
30 etc. Pollux series (Sumitoka Color Co., Ltd.
And the like, and these can be used alone or in combination of two or more.

In addition to water, which is essential as a solvent or a dispersion medium, various water-soluble organic solvents can be used. These have various qualities as aqueous inks, for example, prevention of ink drying at a pen tip, low temperature It is used for purposes such as prevention of ink freezing and a dispersion medium for pigments. Specifically, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, thiodiethylene glycol, hexylene glycol, tetralin, and glycerin; , Ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monoethyl ether, ethylene glycol monobutyl ether, Propylene grease Over mono butyl ether, diethylene glycol monobutyl ether, dipropylene glycol monobutyl ether,
Triethylene glycol monomethyl ether, tripropylene glycol monomethyl ether, triethylene glycol monoethyl ether, tripropylene glycol monoethyl ether, triethylene glycol monobutyl ether, tripropylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate , Ethylene glycol monophenyl ether, ethers such as propylene glycol monophenyl ether, benzyl alcohol, alcohols such as methanol, ethanol, propanol, isopropanol, butanol, N-methyl-2-pyrrolidone, 2-pyrrolidone and the like can be used; These can be used alone or in combination of two or more. A. When the amount is small, insoluble or agglomerated substances are generated due to insufficient dissolution or dispersion of each composition in the ink, and when the amount is large, the concentration of each composition in the ink becomes small and the effect is small. Therefore, the content is preferably 5 to 40% by weight based on the total amount of the water-based ink for ball-point pens.

The minimum film forming temperature which is an essential component is 40 ° C. to 8
In addition to the resin emulsion at 0 ° C., a thickening water-soluble polymer can also be used in combination for adjusting the viscosity of the ink or stabilizing the dispersion of a coloring agent or the like. In particular,
Polyvinyl alcohol, polyvinyl methyl ether, sodium polyacrylate, carboxyvinyl monomer,
Polyethylene oxide, copolymer of vinyl acetate and polyvinylpyrrolidone, alkali metal salt of acrylic resin, copolymer of acrylic acid and alkyl methacrylate, natural gum arabic, tragacanth gum, xanthan gum,
Guar gum, locust bean gum, alginic acid, carrageenan, gelatin, casein, dextran, semi-synthetic methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium starch glycolate, sodium alginate,
Examples include propylene glycol alginate and derivatives thereof.

In order to suppress the outflow inhibition of the ink in the ink passage due to the generation of mold, sodium dehydroacetate, 1,2-benzothiazalin-3-one, methyl-
An appropriate amount of a preservative and fungicide such as 2-benzimidazole carbamic acid ester and sodium benzoate can also be added.

Further, a corrosion inhibitor such as benzotriazole and ethylenediaminetetraacetic acid for preventing metal corrosion and a fatty acid such as oleic acid as a solubilizer can be added.

In producing the ink of the present invention, various conventionally known methods can be employed. For example, it can be easily obtained by mixing and dispersing with a disperser such as a stirrer such as a turbo mixer or a ball mill, a sand grinder, a speed line mill or a roll mill.

[0020]

[Action] Reduced starch saccharified product and minimum film formation temperature of 40 ° C to 80 ° C
It is speculated that the reason why the ink using the resin emulsion at a temperature of ° C. in combination with the ball-point pen ink after storage for a long period of time is excellent in stability is as follows. Minimum film formation temperature of 40 ° C to 80 ° C
The resin emulsion forms a microemulsion structure in an aqueous solution. This microemulsion is
After the ink in the pen tip has been stored for a long period of time, the water content in the pen tip tends to decrease, and the ink inside the pen tip tends to thicken or solidify. The reduced starch saccharified substance enters the microemulsion and works to reduce the effect of trying to form a hard film, fills the small gap between the ball and the forehead, and at the same time increases the viscosity of the ink inside the pen tip after a long period of time. Prevents solidification and does not cause blurring.

[0021]

The present invention will be described below in more detail with reference to examples.

Example 1 FUJI SP BLACK 8556 (black aqueous pigment base, manufactured by Fuji Dye Co., Ltd.) 40.0 parts by weight PO-30 (reduced starch saccharified product, manufactured by Towa Kasei Kogyo East Co., Ltd.) 3.0 parts by weight Part Primal B-74 (minimum film forming temperature 41 ° C, acrylic emulsion, manufactured by Rohm and Haas Japan KK) 3.0 parts by weight Proxel GXL (preservative, manufactured by ICI Japan KK) 0.2 parts by weight ethylene Glycol 15.0 parts by weight Glycerin 5.0 parts by weight Benzotriazole 0.2 parts by weight Ion-exchanged water 33.6 parts by weight The above components were mixed and dispersed in a ball mill for 24 hours. By removing coarse particles, a black aqueous pigment ink was obtained.

Example 2 FUJI SP RED 5544 (red aqueous pigment base, manufactured by Fuji Dye Co., Ltd.) 18.0 parts by weight PO-20 (reduced starch saccharified product, manufactured by Towa Kasei Kogyo Co., Ltd.) 9.0 parts by weight Part Primal WL-81 (minimum film forming temperature 57 ° C, acrylic emulsion, manufactured by Rohm and Haas Japan KK) 4.0 parts by weight Proxel GXL (described above) 0.2 parts by weight ethylene glycol 15.0 parts by weight propylene Glycol 5.0 parts by weight Benzotriazole 0.2 parts by weight PEMULEN TR1 (thickener, alkyl acrylate alkyl methacrylate copolymer, manufactured by Goodrich) 0.3 part by weight Ion-exchanged water 48.3 parts by weight , And subjected to a dispersion treatment in a ball mill for 24 hours. Then, coarse particles are removed by a centrifugal separator to remove the red aqueous pigment ink. Obtained.

Example 3 CI. Direct Black 17 7.0 parts by weight PO-40 (reduced starch saccharified product, manufactured by Towa Kasei Kogyo East Co., Ltd.) 5.0 parts by weight Acronal YJ1100D (minimum film forming temperature 57 ° C., acrylic emulsion, BASF Dispersion Co., Ltd.) 0.5 parts by weight Proxel GXL (described above) 0.2 parts by weight Glycerin 15.0 parts by weight Benzotriazole 0.2 parts by weight PEMULEN TR1 (described above) 0.3 parts by weight Deionized water 72.0 parts by weight Each of the above The components were mixed and mixed for 4 hours with a stirrer to obtain a black aqueous dye ink.

Example 4 FUJI SP MAGENTA 9316 (magenta aqueous pigment base, manufactured by Fuji Dye Co., Ltd.) 20.0 parts by weight PO-20 (reduced starch saccharified product, manufactured by Towa Kasei Kogyo East Co., Ltd.) 0 parts by weight Acronal YJ1100D (minimum film forming temperature 57 ° C., acrylic emulsion, manufactured by BASF Dispersion Co., Ltd.) 1.5 parts by weight Proxel GXL (described above) 0.2 parts by weight propylene glycol 15.0 parts by weight benzotriazole 0 0.2 parts by weight PEMULEN TR1 (described above) 0.3 parts by weight Ion-exchanged water 61.8 parts by weight After mixing the above components and performing a dispersion treatment for 24 hours in a ball mill, coarse particles are removed by a centrifugal separator. Thus, a red aqueous pigment ink was obtained.

Example 5 Pollux Blue PC5T-1020 (blue aqueous pigment base, manufactured by Sumika Color Co., Ltd.) 22.00 parts by weight PO-20 (reduced starch saccharified product, manufactured by Towa Kasei Kogyo East Co., Ltd.) 00 parts by weight Primal B-924 (minimum film formation temperature 75 ° C., acrylic emulsion, manufactured by Rohm and Haas Japan KK) 0.40 parts by weight Proxel GXL (described above) 0.25 parts by weight ethylene glycol 16.00 parts by weight Glycerin 15.00 parts by weight Benzotriazole 0.20 parts by weight Tartaric acid 0.30 parts by weight Ion-exchanged water 44.85 parts by weight The above components were mixed and dispersed in a ball mill for 24 hours. By removing coarse particles, a blue aqueous pigment ink was obtained.

Comparative Example 1 A black aqueous pigment ink was obtained in the same manner as in Example 1 except that PO-30 was added and glycerin was added in that amount.

Comparative Example 2 A red aqueous pigment ink was obtained in the same manner as in Example 2, except that Primal WL-81 was used and ion-exchanged water was added in that amount.

Comparative Example 3 Example 3 was repeated except that Acronal YJ1100D was used.
An aqueous black dye ink was obtained in the same manner as in Example 3 except that ion-exchanged water was added in that amount.

Comparative Example 4 Example 4 was repeated except that Acronal YJ1100D was used.
Primal B-90 (the minimum film formation temperature: 90)
A water-based red pigment ink was obtained in the same manner as in Example 4 except that an acrylic emulsion, Rohm and Haas Japan Co., Ltd.) was added.

The aqueous pigment or dye ink obtained in each of Examples 1 to 5 and Comparative Examples 1 to 4 was applied to a stainless ballpoint pen tip having a ball diameter of φ0.6 mm (ball material: cemented carbide,
0.8 g of a transparent ink container consisting of a hollow cylinder made of polypropylene connected to one end with a ball pushed up by a spring) was filled, and the pen tip was exposed to prepare a test sample. After being left in a constant temperature room for 2 months, the writing function was checked.

Confirmation of writing function: 5
After taking out from the 0 ° C constant temperature room and leaving it at room temperature for 2 hours,
A circle of 1.5 cm in diameter was continuously written in a spiral shape with 20 circles by hand, and handwriting was performed, and the degree of blurring was visually evaluated.
Table 1 shows the results.

[0033]

[Table 1]

[0034]

As described in detail above, the aqueous ink according to the present invention does not cause deterioration of the ink due to thickening or solidification of the ink even after aging for a long time.
It has an excellent effect that no blur occurs when writing.

Claims (3)

[Claims] An aqueous ink for a ballpoint pen, comprising at least water, a colorant, a saccharified reduced starch, and a resin emulsion having a minimum film-forming temperature of 40 ° C to 80 ° C. 2. The water-based ink for a ball-point pen according to claim 1, wherein the ball-point pen is a ball-point pen of a type whose tip is always open. 3. The water-based ink for a ball-point pen according to claim 1, wherein the ball-point pen is a ball-point pen having a pen tip protruding and retracting from the tip of a writing instrument.