JP2003113340A - Water-based ink composition for ball-point pen and ball- point pen filled therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ink composition for ball-point pens having such dry-up-proof performance and sag performance as to retain ink delivery similarly to that in the initial stage in making a writing even if a writing tip is left to stand in a condition of being exposed to the outside air, good at pigment dispersibility when a pigment is used as the colorant, and affording handwriting of color density similar to that in the initial stage even after the lapse of time, and to provide a ball-point pen filled with the water-based ink composition and having a knocking-, turning- or sliding-type extending/retracting mechanism or the like. SOLUTION: This water-based ink composition for ball-point pens essentially comprises a colorant, water, a shearing diminished viscosity-imparting agent, and trehalose.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous ink composition for ballpoint pens. More specifically, the present invention relates to a water-based ink composition for ball-point pens, which has excellent dry-up resistance and sag-preventing performance on a pen tip and which has shear thinning properties.

[0002]

2. Description of the Related Art In recent years, ink compositions for writing instruments are roughly classified into water-based ink compositions containing water as a main solvent and oil-based ink compositions containing an organic solvent as a main solvent. Water-based ink compositions are being widely used in consideration of their properties. Among them, a water-based ink for a ball-point pen having a shear thinning property has been developed for the purpose of overcoming the disadvantages of a conventional oil-based ball-point pen and the disadvantages of a writing hand of a low-viscosity water-based ball-point pen. Examples of thickening agents (shear reducing viscosity imparting agents) in shear thinning inks include gums such as xanthan gum and succinoglycan, crosslinked acrylic acid polymers, nonionic surfactants of HLB 8 to 12, and association type urethane. Polyether is used (Japanese Patent Laid-Open No. 59-74175).
JP-A-6-88050 and JP-A-9-302299
No. However, gums such as xanthan gum and succinoglycan used for the purpose of imparting such shear thinning properties, and nonionic surfactants of HLB8 to 12 may impair dry-up resistance. Therefore, it has been proposed to add an additive such as a water-soluble organic solvent, a wetting agent such as polyhydric alcohol, or a solid wetting agent such as urea to improve the dry-up resistance. However, the ink containing the additive has an insufficient anti-drying effect, increases the ink viscosity, and easily causes writing defects such as fading. For example, excessive addition of urea causes moisture to evaporate from the writing tip and the concentration of the water-soluble organic solvent rises, so that the solid content is deposited on the writing tip, which is a so-called flower bloom phenomenon and makes the appearance poor. At the same time, fading etc. occurs. Further, urea and its derivatives have an adverse effect such that ammonia is generated due to decomposition and the pH of the ink is increased to accelerate the aggregation of the pigment, so that a satisfactory aqueous ink composition cannot be obtained. It was Further, addition of hygroscopic sugars such as sorbit, sucrose, maltose, and reduced maltose has been proposed, but the effect of preventing nib dryness was not sufficient. Furthermore, the addition of a large amount of water-soluble organic solvent, urea and its derivatives, and hygroscopic sugars,
Especially when the pen tip is left downward in a humid environment,
There are some negative effects such as drooping. Also,
Pigments and dyes are used as colorants, but when pigments are used, they are more excellent in water resistance and light resistance in handwriting than dyes, but they tend to agglomerate or settle in the ink and cannot be written over time. , The problem that light and shade occurs in the handwriting occurs. On the other hand, it has been attempted to increase the viscosity of the ink to suppress the sedimentation of the pigment, but the increase in the viscosity decreases the ink discharge amount, and as a result, the handwriting is likely to be faint, which is good. It becomes difficult to obtain accurate handwriting.
Furthermore, as compared with a water-based ink composition using a dye, the solid content (colorant, resin, etc.) concentration is likely to increase due to water evaporation,
Since the ink discharge amount tends to decrease, if the writing tip end is left exposed to the outside air, the handwriting may be faint in a short time, or writing may be impossible.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the conventional water-based pigment ink composition, that is, the water-based ink composition for ballpoint pens which satisfies both the dry-up resistance and the drooping property. It is to provide an object and a ballpoint pen having the object built therein.

[0004]

The present invention requires a water-based ink composition for ball-point pens, which contains at least a colorant, water, a shear thinning agent and trehalose. Further, it is required that the trehalose is contained in an amount of 1 to 15% by weight with respect to the total amount of the ink composition, and the colorant is a pigment. Furthermore, a ball-point pen comprising the above water-based ink composition for a ballpoint pen contained in a refill, and the tip of the refill housed in the barrel is freely retractable from the tip hole of the barrel by operating the retracting mechanism. As a requirement.

The trehalose used in the present invention is a compound represented by the following general formula (1), which is a non-reducing saccharide in which two glucose molecules are bound by α, α-1,1. Has the highest stability to heat and acid, and does not deteriorate in the ink. Therefore, it is considered that it shows a better dry-up resistance than other sugars. Also,
Trehalose does not absorb moisture up to 95% relative humidity, so
Addition of other water-soluble organic solvents or urea and its derivatives has the function of suppressing the adverse effects such as sagging and dripping that occur due to water absorption in the air due to high humidity. Further, the above-mentioned gums, shear thinning agents such as water-soluble polymers easily form a very strong dry film when water is evaporated at the pen tip, and therefore, the writing part is exposed to the outside air for a long time. When left in an exposed state, it becomes easy to write, but it is considered that the addition of trehalose has a function of preventing the formation of this dry film.

[0006]

[Chemical 1]

The amount of trehalose used in the present invention is 1 to 15% by weight, preferably 3 to 10% by weight, based on the total amount of the ink. If the amount is less than 1% by weight, the effect of dry-up resistance is small, and if the amount is more than 15% by weight, the viscosity of the ink is increased, which may cause crying or bloating, or hinder the followability.

As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used,
Specific examples thereof will be illustrated below. As the dye, an acid dye, a basic dye, a direct dye or the like can be used. As an acid dye, Neucoccin (C.I. 16
255), tartrazine (C.I. 19140), acid blue black 10B (C.I. 20470), guinea green (C.I. 42085), brilliant blue FCF (C.I. 42090), acid violet 6B (C). .I. 42640), soluble blue (C.I. 42755), naphthalene green (C.I.
I. 44025), eosin (C.I. 45380),
Phloxine (CI.45410), Erythrosin (CI.45430), Nigrosine (CI.504)
20), acid flavin (CI.56205) and the like are used.

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

As a direct dye, Congo red (C.
I. 22120), Direct Sky Blue 5B (C.
I. 24400), violet BB (C.I.279)
05), Direct Deep Black EX (C.I.3)
0235), Kayarasu Black G Conc (C.I. 35)
225), Direct Fast Black G (C.I.3)
5255), phthalocyanine blue (C.I. 7418)
0) and the like are used.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine blue, organic pigments such as copper phthalocyanine blue and benzidine yellow, and finely and stably dispersed in an aqueous medium in advance using a surfactant and a resin. Water-dispersed pigment products and the like are used. I. Pigment
Blue 15: 3B [Product name: Sandye Supe
r Blue GLL, pigment content 24%, Sanyo Dye Co., Ltd.], C.I. I. Pigment Red 146
[Product Name: Sandye Super Pink FB
L, pigment content 21.5%, Sanyo Dye Co., Ltd.], C.I.
I. Pigment Yellow 81 [Product Name: TC
YellowFG, pigment content about 30%, made by Dainichiseika Kogyo Co., Ltd., C.I. I. Pigment Red 220
/ 166 [Product name: TC Red FG, pigment content about 35
%, Manufactured by Dainichiseika Kogyo Co., Ltd.] and the like. As the resin for dispersing the pigment, polyamide resin, polyurethane resin, polyester resin, epoxy resin, melamine resin, phenol resin, silicone resin, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride,
Examples thereof include polystyrene, acrylic acid resins, maleic acid resins, gum arabic, cellulose, dextran, casein and the like, derivatives thereof, and copolymers of the above resins. As the fluorescent pigment, synthetic resin fine particle fluorescent pigment in which various fluorescent dyes are solid-solved in a resin matrix can be used. Further, a white pigment such as titanium dioxide, a metal powder such as aluminum, a pearl pigment, a gold or silver metallic pigment, a luminous pigment, a perfume or a perfume capsule pigment may be used. The pigments can be used alone or in admixture of two or more kinds.
It is used in the range of 25 to 25% by weight, preferably 2 to 15% by weight.

Further, as the water-soluble organic solvent, a conventionally used solvent which is compatible with water can be used. The water-soluble organic solvent, ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, hexylene glycol, 1,3-butanediol, neoprene glycol, Polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether diethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 2-pyrrolidone,
N-methyl-2-pyrrolidone and the like can be mentioned. The water-soluble organic solvent may be used alone or in combination of two or more, and is used in the range of 2 to 60% by weight, preferably 5 to 35% by weight, based on the total amount of the ink composition.

In addition, a pH adjusting agent, an antiseptic agent or an antifungal agent can be added if necessary. Examples of the pH adjusting agent 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 triethanolamine and diethanolamine. Examples of the preservative or antifungal agent include carboxylic acid, sodium salt of 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6. −
Tetrachloro-4- (methylsulfonyl) pyridine and the like can be mentioned. In addition, a fluorine-based, nonionic-based, anionic-based, or cationic-based surfactant that improves the permeability of the solvent, or a defoaming agent such as dimethylpolysiloxane may be added.

Further, one or more kinds of water-soluble resins such as alkyd resin, acrylic resin, styrene-maleic acid copolymer, cellulose derivative, polyvinylpyrrolidone, polyvinyl alcohol and dextrin are added within a range that does not impair the drying resistance. Alternatively, one or more kinds of wetting agents such as urea, nonionic surfactant, sorbit, mannitol, sucrose, glucose, reduced starch hydrolyzate and sodium pyrophosphate may be added.

The shear thinning property of an ink composition is a rheological property in which it has a property of being extremely high in viscosity and hard to flow when it is in a static state or a low stress, and has a low viscosity and good flowability when stress is increased. And means liquidity also called thixotropic or pseudoplasticity. Therefore, in the ink composition, under high shear stress during writing, the three-dimensional structure is temporarily destroyed and the viscosity of the ink decreases, and the ink at the tip of the writing becomes a low viscosity ink suitable for writing,
It is transferred to the paper. When not writing, the viscosity of the ink becomes high, and it is possible to prevent ink leakage, ink separation, and backflow. Also, the physical properties of the ink can be kept stable over time. In particular, with a ballpoint pen holding the ball at the writing tip, the ink near the ball has a low viscosity suitable for writing under high shear stress during writing, and the gap between the ball and the ball house moves due to capillary force to the paper surface. It is necessary to have ink characteristics that can be transferred to the ink, and when not writing, the viscosity of all ink, including the area near the ball, becomes high, and it is necessary to prevent ink leakage, ink separation, and backflow. , 100rpm by E type rotational viscometer
The ink viscosity at m is 20 to 200 mPa · s (25
C.) and a shear thinning index of 0.1 to 0.8 is suitable. The shear thinning index n
Is an empirical formula T = Kj ⁿ (T: shear stress value, j: shear rate,
K is obtained by applying a numerical value to the calculated constant).

As the shear thinning agent, a substance soluble or dispersible in water is effective, and xanthan gum, welan gum, and succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose. (Average molecular weight of about 1 to 8,000,000), guar gum, locust bean gum and its derivatives, hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 containing an alkyl ester of methacrylic acid as a main component, glycomannan, Thickening polysaccharides having gelling ability extracted from seaweeds such as agar and carrageenan, benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymers, inorganic fine particles,
Polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene castor oil, polyoxyethylene lanolin, lanolin alcohol, beeswax derivative, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polyoxyethylene alkyl HLB value of phenyl ether, fatty acid amide, etc. is 8
Examples of the nonionic surfactants to 12 and salts of dialkyl or dialkenylsulfosuccinic acid can be used, and they can be used alone or in combination. Furthermore, N-alkyl-
It is also possible to use a mixture of 2-pyrrolidone and an anionic surfactant and a mixture of polyvinyl alcohol and an acrylic resin. The shear thinning agent may be used in the ink composition in an amount of 0.1 to 20% by weight.

In addition, a rust preventive agent, a lubricant and the like can be added if necessary. Examples of the rust inhibitor include benzotriazole and its derivative, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, sodium thiosulfate, ethylenediaminetetraacetic acid salt, saponin, dialkylthiourea and the like. Examples of the lubricant include metal soaps, polyalkylene glycol fatty acid esters, ethylene oxide addition type cationic activators, phosphoric acid ester activators, thiocarbamate salts, dimethyldithiocarbamate salts and the like.

The lubricant preferably used is
Examples include the phosphoric acid ester-based surfactants described in the following general formula (2) or Japanese Patent Publication No. 13508/1989.

[Chemical 2] (In the formula, R₁ Is an 8-18 alkyl group, an alkenyl group,
Alternatively, it represents a phenyl group or an alkylphenyl group, and R₂ 
Is OH, OM, R₁ -O- (CH₂ CH₂ O) _n Shows
M is an alkali metal, amine, alkanolamine
And n represents 1 to 30. )

The water-based ink composition for ball-point pens of the present invention is not particularly limited in the structure and shape of the ball-point pen itself, and conventional ones can be applied. For example, a barrel is filled with the ink composition. An example is a ballpoint pen that has an ink storage tube, the ink storage tube communicates with a tip having a ball attached to the tip, and a backflow prevention liquid stopper is in close contact with the end surface of the ink.

The ballpoint pen filled with the ink composition will be described in more detail. As for the structure of the writing tip (tip), a general-purpose mechanism has been more effective than before, and the vicinity of the tip of the metal pipe is more inward than the outer surface. A chip formed by holding a ball in the ball holding portion that has been deformed by pressing, or a chip formed by holding a ball in a ball holding portion formed by cutting a metal material with a drill or the like, or a metal-made chip. It is possible to apply, for example, a ball or a ball held by a chip formed by cutting a pipe or a metal material, which is biased forward by a spring body. Further, as the balls, those having a diameter of about 0.3 to 1.2 mm, such as cemented carbide, stainless steel, ruby, and ceramic, can be applied.

For the ink containing tube containing the ink composition, a molded article made of a thermoplastic resin such as polyethylene, polypropylene or polyethylene terephthalate is preferably used in view of low ink evaporation and productivity. Further, the ink containing tube having an inner diameter of 2.5 to 10 mm is preferably used. Furthermore, by using a transparent, colored transparent, or translucent molded body as the ink containing tube, the ink color, the ink remaining amount, etc. can be confirmed. In addition to directly connecting the chip to the ink containing tube, the ink containing tube and the chip may be connected via a connecting member. Incidentally, the ink containing tube may be one in which the refill is housed in the barrel as a form of a refill for a ballpoint pen, or the barrel itself having a tip attached to the tip is used as an ink container in the barrel. The ink may be directly filled. The inner diameter of the refill housed in the barrel is 2.5 to
The inner diameter of the shaft cylinder for directly containing the ink is preferably 4 to 10 mm.

It is preferable that the back end of the ink composition contained in the ink container is filled with an ink backflow preventer. The ink backflow preventer may be liquid or solid, and the liquid ink backflow preventer may be polybutene, α-olefin oligomer,
Non-volatile media such as silicone oil and refined mineral oil are listed,
If desired, silica, aluminum silicate, swelling mica, fatty acid amide and the like can be added to the medium.
Further, as the solid ink backflow preventer, a resin molded product can be mentioned. Furthermore, the liquid and solid ink backflow preventives can be used in combination.

The ball-point pen may have any structure, but since it has excellent dry-up resistance, it has a retracting mechanism that is stored in the barrel while the writing part is exposed to the outside air. Especially effective. As a method of operating the retractable mechanism, for example, a knock type,
Examples include a rotary type and a slide type.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The water-based ink composition for a ballpoint pen of the present invention comprises a medium consisting of water and a water-soluble organic solvent, to which a colorant, trehalose, and additives are added, if necessary. It is prepared by heating, stirring if necessary, dissolving and dispersing, and filling a ballpoint pen for use.

[0025]

EXAMPLES The formulations of the water-based ink compositions for ballpoint pens prepared in Examples 1 to 4 and Comparative Examples 1 to 6 are shown below.
The numerical values indicate parts by weight.

[0026]   Example 1   Black pigment 40.0   [Product name: SP Black 8922, manufactured by Fuji Dye Co., Ltd.]   (Carbon black 20%, diethylene glycol 15%, anionic activity Agent 6%, water 49%)   Ethylene glycol 10.0   Diethylene glycol 5.0   Urethane-based association resin emulsion 2.5   [Product name: Leolate 299, manufactured by Elementis Japan KK]   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   Trehalose [Hayashibara Shoji Co., Ltd.] 10.0   1,3 Diethylthiourea 0.3   Water 31.5

Additives other than the pigment are put into water in advance and stirred, and then the pigment is put into the disperser at 2000 rpm.
And stirred for 10 minutes to prepare a black aqueous ink.

[0028]   Example 2   Black pigment 50.0   [Product name: WA Black A250, manufactured by Dainichiseika Kogyo Co., Ltd.] (Carbon black 15%, diethylene glycol 20%, acrylic resin 5 %, Water 60%)   Glycerin 5.0   Ethylene glycol 5.0   Urethane-based association resin emulsion 2.5   [Product name: TAFGEL PUR60,                             Made by MUNZING CHEMIE GMBH]   Butyl carbitol 0.5   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   Trehalose [Hayashibara Shoji Co., Ltd.] 5.0   1,3 Diethylthiourea 0.3   Water 31.0

After preparing a solution in which TAFGEL PUR 60 and butyl carbitol were mixed in advance, various additives were added and mixed, and then a pigment was added and the mixture was mixed with a disper to 200
A black aqueous ink was prepared by stirring at 0 rpm for 10 minutes.

[0030]   Example 3   Blue pigment 50.0   [Product name: Fuji SP Blue 6401, manufactured by Fuji Dye Co., Ltd.]   (Copper phthalocyanine blue 19%, diethylene glycol 8%, anion 2.5% of surface active agent, 70.5% of water)   Ethylene glycol 5.0   Urea 5.0   Alkali thickening resin emulsion 2.2   [Product name: Primal ASE-60, made by Rohm and Haas]   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   Trehalose [Hayashibara Shoji Co., Ltd.] 7.0   1,3 Diethylthiourea 0.3   Water 29.8

Additives other than the pigment are put into water in advance and stirred, and then the pigment is put into the disperser at 2000 rpm.
And stirred for 10 minutes to prepare a blue water-based ink.

[0032]   Example 4   Black dye 40.0   [Product name: Water Black 100L, manufactured by Orient Chemical Industry Co., Ltd.]   (C / I Direct Black 19 20%, Water 80%)   Xanthan gum 0.4   Glycerin 10.0   Diethylene glycol 10.0   Urea 10.0   Trehalose [Hayashibara Shoji Co., Ltd.] 10.0   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.5   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   1,3 Diethylthiourea 0.5   Water 18.1

After preliminarily accommodating glycerin and xanthan gum, add a small amount of water and disperse at 6000 rpm.
Stir for 10 minutes, then add it to an aqueous solution in which other additives and water are separately mixed, and further disperse at 6000 rpm for 1 minute.
The mixture was stirred for 0 minutes to prepare a black aqueous ink.

[0034]   Comparative Example 1   Black pigment 40.0   [Product name: SP Black 8922, manufactured by Fuji Dye Co., Ltd.]   (Carbon black 20%, diethylene glycol 15%, anionic activity Agent 6%, water 49%)   Ethylene glycol 10.0   Diethylene glycol 5.0   Urethane-based association resin emulsion 2.5   [Product name: Leolate 299, manufactured by Elementis Japan KK]   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   1,3 Diethylthiourea 0.3   Water 41.5

[0035]   Comparative example 2   Black pigment 50.0   [Product name: WA Black A250, manufactured by Dainichiseika Kogyo Co., Ltd.]   (15% carbon black, 20% diethylene glycol, acrylic resin 5%, water 60%)   Glycerin 5.0   Urethane-based association resin emulsion 2.5   Ethylene glycol 5.0 [Product name: TAFGEL PUR60,                           Made by MUNZING CHEMIE GMBH]   Butyl carbitol 0.5   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   1,3 Diethylthiourea 0.3   Water 36.0

[0036]   Comparative Example 3   Blue pigment 50.0   [Product name: Fuji SP Blue 6401, manufactured by Fuji Dye Co., Ltd.]   (Copper phthalocyanine blue 19%, diethylene glycol 8%, anion 2.5% of surface active agent, 70.5% of water   Ethylene glycol 5.0   Urea 5.0   Alkali thickening resin emulsion 2.2   [Product name: Primal ASE-60, made by Rohm and Haas]   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   1,3 Diethylthiourea 0.3   Water 36.8

[0037]   Comparative Example 4   Black dye 40.0   [Product name: Water Black 100L, manufactured by Orient Chemical Industry Co., Ltd.]   (C / I Direct Black 19 20%, Water 80%)   Xanthan gum 0.4   Glycerin 10.0   Diethylene glycol 10.0   Urea 10.0   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.5   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   1,3 Diethylthiourea 0.5   Water 28.1

[0038]   Comparative Example 5   Black pigment 40.0   [Product name: SP Black 8922, manufactured by Fuji Dye Co., Ltd.]   (Carbon black 20%, diethylene glycol 15%, anionic activity Agent 6%, water 49%)   Ethylene glycol 10.0   Diethylene glycol 5.0   Urethane-based association resin emulsion 2.5   [Product name: Leolate 299, manufactured by Elementis Japan KK]   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   Glycerin 10.0   1,3 Diethylthiourea 0.3   Water 31.5

[0039]   Comparative Example 6   Blue pigment 50.0   [Product name: Fuji SP Blue 6401, manufactured by Fuji Dye Co., Ltd.]   (Copper phthalocyanine blue 19%, diethylene glycol 8%, anion 2.5% of surface active agent, 70.5% of water   Ethylene glycol 5.0   Urea 5.0   Alkali thickening resin emulsion 2.2   [Product name: Primal ASE-60, made by Rohm and Haas]   Phosphate ester type surfactant 0.5   [Lubricant, trade name: Prysurf A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.]   1,2-benzthiazolin-3-one 0.2   [Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.]   Anhydrous crystalline maltose 7.0   1,3 Diethylthiourea 0.3   Water 29.8

1 ml of the ink prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was fitted with a stainless steel chip holding a cemented carbide ball having a diameter of 0.5 mm at one end of a polypropylene cylinder. Filled with a ball-point pen of the above-mentioned form, and further filled with 0.1 g of a backflow preventer (silicone grease type) by closely contacting with the rear end surface of the ink and subjected to centrifugal treatment. 3 were prepared for each.

Dry-up resistance test In the state where the pen tip of each ballpoint pen is exposed to the outside air,
In Table 1, after being left for 60 days under the conditions of 20 ° C. for A and 50 ° C. for B, the handwriting was written on the paper surface and the handwriting was visually observed. Dripping test With the pen tip of each of the above ballpoint pens exposed to the outside air, at C in Table 1 at 20 ° C.,
Under 95RH conditions, with the pen tip inverted, 2
After standing for a time, the tip of the chip was visually observed. The results are shown in the table.

[0042]

[Table 1]

The judgment results in the table are shown below. Dry-up resistance performance test ◯: Recovered within 1 line of report paper. Δ: Recovered within 3 lines of report paper. X: The report is not recovered within 3 lines. Droop test ○: No abnormality. Δ: Some drops were generated at the tip of the tip. ×: Drops or dripping occurred.

[0044]

INDUSTRIAL APPLICABILITY By adding trehalose, the present invention can provide a water-based ink composition for a ballpoint pen having excellent dry-up resistance and hanging performance of a pen tip, and a ballpoint pen incorporating the same.

Continued front page    F-term (reference) 2C350 GA03 HA08 NA10 NA11                 4J039 AB01 AB02 AB07 AD03 AD05                       AD06 AD08 AD10 AD14 AE02                       AE03 AE04 AE05 AE06 AE08                       AE11 BA06 BA12 BA32 BA35                       BC07 BC09 BC12 BC20 BC35                       BE01 BE02 BE03 BE04 BE05                       BE12 BE23 CA03 EA16 EA17                       EA19 EA20 EA21 EA41 EA42                       GA27

Claims (4)

[Claims] 1. A water-based ink composition for a ball-point pen, which contains at least a colorant, water, a shear thinning agent, and trehalose. 2. The aqueous ink composition for a ballpoint pen according to claim 1, wherein the trehalose is contained in an amount of 1 to 15% by weight based on the total amount of the ink composition. 3. The colorant according to claim 1, which is a pigment.
The water-based ink composition for ballpoint pens described above. 4. A water-based ink composition for a ballpoint pen according to any one of claims 1 to 3 is contained in a refill,
A ballpoint pen in which a pen tip of a refill housed in a barrel is configured to be retractable from a tip hole of the barrel by operating a retracting mechanism.