JP2003201433A - Water-based ink composition for writing utensils - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a water-based ink composition which has excellent so-called cap-off performance (dry-up resistance performance) causing neither blur nor inability to write due to drying of pen point and does not bring about sagging or ink drop resulting from partial reduction in ink viscosity due to moisture absorption at the part of pen point. <P>SOLUTION: The water-based ink for writing utensils is obtained by adding a saccharified reduced starch being a hydrogenated (reduced) product of any of various kinds of glucose syrups prepared by subjecting starch to enzymatic hydrolysis to an ink composition comprising at least a colorant and water. The saccharified reduced starch is a stable substance causing neither discoloration nor browning by heating and has properties that the composition to which the saccharified reduced starch is added is provided with moisture retaining property and yet the moisture retaining property is low. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water-based ink composition for writing instruments. More specifically, even when writing is performed immediately after leaving the cap removed for a long period of time, there is no scratching or inability to write due to the drying of the pen tip, and so-called cap-off property (dry-up resistance) is excellent. And a water-based ink composition for a writing instrument.

[0002]

2. Description of the Related Art Conventionally, a water-soluble organic solvent, urea, a urea derivative or the like has been generally used as a pen tip drying inhibitor for a water-based ink for writing instruments. Particularly in recent years, the ink composition for a writing instrument that uses a pigment as a coloring agent has been generally used with emphasis on the fastness of handwriting, but a pigment ink is more likely to dry at a pen tip than an ink using a dye. There is a drawback that the writability does not recover quickly even if the cap is put on and left after drying.

In the field of water-based ballpoint pens, a so-called "gel ballpoint pen" having a structure in which a shear thinning ink is directly contained in an ink containing tube and an ink backflow preventive member is provided at a rear end of the ink is on the market. The ink used for this type of ball-point pen is a shear thinning agent such as gums such as xanthan gum and succinoglycan, cross-linked acrylic acid polymers, nonionic surfactants with HLB value of 8 to 12, and associated agents. Type urethane has been proposed and put to practical use.
However, these shear thinning agents all significantly deteriorate the cap-off performance.

Therefore, it is necessary to further improve the cap-off performance of the shear thinning water-based ballpoint pen ink, and it has been attempted to increase the amount of the water-soluble organic solvent, urea and / or its derivative.

[0005]

However, for example, a water-soluble organic solvent represented by a polyhydric alcohol such as glycerin or ethylene glycol needs to be added in a large amount in order to obtain sufficient cap-off performance. Due to the increase in ink viscosity, various problems such as poor ink followability at high speed writing, poor handwriting drying, and handwriting blurring occur. Although urea or urea derivatives have some improvement in cap-off performance, they decompose during storage in a high-temperature environment to generate ammonia, which raises the pH of the ink and induces solid analysis at the pen tip. Addition of a large amount such as a phenomenon causes deterioration of the performance of the writing instrument.

Although the water-soluble organic solvent, urea and / or urea derivative and the like have a high water-absorption capability, the cap-off capability is exhibited. However, the ink containing the conventional cap-off capability-imparting agent excessively has a high humidity. If the writing instrument is left under the conditions, the pen tip portion will absorb water locally. Therefore, for example, when such an ink is applied to a knock type water-based ballpoint pen, the ink viscosity of the pen tip portion decreases due to water absorption, causing the ink to "droop" or "drop off" where the accumulated ink falls. The phenomenon occurs.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies as to an additive which imparts good cap-off performance while preventing sagging and dripping, and as a result, good cap-off by addition of reduced starch saccharified product. It was found that a water-based ink composition having performance and free from sagging or dripping can be obtained.

That is, the present invention requires that the aqueous ink composition for a writing instrument contains at least a colorant, water, and a reduced starch saccharified product. Furthermore, the reduced starch saccharified product comprises reduced starch syrup and / or a branched branched oligosaccharide, and the reduced starch saccharified product is blended in a range of 2.0 to 20.0% by weight with respect to the total amount of the ink composition. And 60 to 80% by weight of the reduced starch saccharified product is a polysaccharide of 4 to 8 saccharides, containing a non-alkali thickening type and / or a hardly alkaline thickening type acrylic resin emulsion, and It is required that the non-alkali thickening type and / or hardly alkaline thickening type acrylic resin emulsion is blended in the range of 2.5 to 15.0% by weight based on the total amount of the ink composition. Furthermore, the above-mentioned water-based ink composition for a writing instrument is an ink for a ball-point pen to which a shear thinning agent is added, and the water-based ball-point pen is attached to an ink storage tube attached with a ball-point pen tip directly or through a connecting member. The requirement is that the ink is directly stored.

The reduced starch saccharified product used in the present invention is obtained by hydrogenating (reducing) various starch syrups obtained by enzymatically decomposing starch, and is highly safe to be added to foods. Although it is a compound, it imparts moisturizing properties to the compounded composition, but has a property of low hygroscopicity and excellent stability such that it is not colored or browned by heating. Therefore, a writing instrument containing the aqueous ink composition for a writing instrument of the present invention has a significantly improved cap-off property, and when the applied writing instrument is a ballpoint pen, it is possible to further prevent drooping and dripping. It was

The reduced starch saccharified product is added in an amount of 2.0 to 20.0% by weight based on the total amount of the ink composition.
If it is less than 2.0% by weight, the effect of the dry-up resistance is small, and if it is more than 20.0% by weight, the viscosity of the ink is increased to cause crying out or bloating, or hinder the followability. Used in the range of 2.0 to 20.0% by weight,
It is preferably blended in the range of 3.0 to 15.0% by weight.

Usually, the reduced starch saccharified product is a mixture of monosaccharides, oligosaccharides and polysaccharides, but monosaccharides and disaccharides have a small effect on the cap-off property and have high water absorption, so when applied to a ballpoint pen, If the tip is left facing down (upside down), it is likely to sag. Further, an attempt to add reduced dextrin has been conventionally disclosed (WO99 /
No. 02617), however, since this compound has a large molecular weight, the viscosity of the ink is extremely increased and the writing performance is adversely affected, and the moisturizing effect is not sufficient, and it is difficult to put it into practical use. It was clarified that the reduced starch saccharified product containing sugar as the main component was the most effective.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As the colorant used in the present invention, all dyes and pigments which can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof are shown below. As the acid dyes, new coccin (CI. 16255), 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. 4)
2755), naphthalene green (C.I. 4402)
5), Eosin (CI.45380), Phloxine (CI.45410), Erythrosin (CI.45).
430), nigrosine (CI. 50420), acid flavin (CI. 56205) and the like.

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.

As the pigment, in addition to inorganic pigments such as carbon black and ultramarine blue, organic pigments such as copper phthalocyanine blue and benzidine yellow, a surfactant and a water-soluble resin have already been used in a fine and stable manner in an aqueous medium. Dispersed water-dispersed pigment products and the like are used, and examples of the water-dispersed pigment using a surfactant include C.I. I. Pigment Blu
e 15: 3B [Brand name: Sandye Super
Blue GLL, pigment content 24%, Sanyo Dye Co., Ltd.
Manufactured], C.I. I. Pigment Red 146 [trade name: Sandy Super Pink FBL,
Pigment content 21.5%, Sanyo Dye Co., Ltd.], C.I. I. Pi
gment Yellow 81 [Product Name: TC Ye
lowFG, pigment content about 30%, Dainichiseika Kogyo Co., Ltd.
Manufactured], C.I. I. Pigment Red 220/166
[Brand name: TC Red FG, pigment content about 35%, manufactured by Dainichiseika Kogyo Co., Ltd.] and the like. Further, as the water-dispersed pigment using the water-soluble resin, C.I. I. Pig
ment Black 7 [Product Name: WA color
Black A250, pigment content 15%, Dainichiseika Kogyo KK], C.I. I. Pigment Green 7
[Product name: WA-S colorGreen, pigment content 8
%, Manufactured by Dainichiseika Kogyo Co., Ltd.], C.I. I. Pigment
Violet 23 [Product Name: Micro Pigmo WM
VT-5, pigment content 20%, Orient Chemical Industry Co., Ltd.
Manufactured], C.I. I. Pigment Yellow 83
[Product name: Emmacor NS Yellow 4618, pigment content 3
0%, manufactured by Sanyo Dye Co., Ltd.].

As the fluorescent pigment, a synthetic resin fine particle fluorescent pigment in which various fluorescent dyes are solid-solved in a resin matrix can be used. Others, pearl pigment, metal powder pigment,
Luminescent pigments, white pigments such as titanium dioxide, silica and calcium carbonate, capsule pigments containing a thermochromic composition,
Examples thereof include fragrances and capsule pigments containing fragrances. The colorants may be used alone or in admixture of two or more, and are used in an ink composition of 1 to 25% by weight, preferably 2
Used in the range of up to 15% by weight.

Water is used as the main solvent of the aqueous ink composition for a writing instrument of the present invention, but if necessary, a water-soluble organic solvent compatible with water can be added. Examples of the water-soluble organic solvent include ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol,
Thiodiethylene glycol, polyethylene glycol,
Propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2- Examples include pyrrolidone and N-methyl-2-pyrrolidone. The water-soluble organic solvent may be used alone or in combination of two or more.
It is used in an amount of 0% by weight, preferably 5 to 40% by weight.

Further, although the reduced starch saccharified product has a slight effect of improving the color tone of handwriting, the aqueous ink composition for a writing instrument of the present invention contains a non-alkali thickening type and / or a slightly alkaline thickening type acrylic resin emulsion. The color tone and the density can be significantly improved by adding. By adding a non-alkali thickening type and / or a slightly alkaline thickening type acrylic resin emulsion to the aqueous ink without adding the reduced starch saccharification product, the color tone and density of the handwriting can be significantly improved. It is difficult to use the non-alkali thickening type and / or hardly alkaline thickening type acrylic resin emulsion alone, because the drying property of the ink becomes high and the cap-off performance is lowered. However, when used in combination with the reduced starch saccharified product, the color tone and density of the handwriting can be significantly improved without lowering the cap-off performance. The non-alkali thickening-type and / or hardly alkaline thickening-type acrylic resin emulsion is one that does not substantially swell even when reacted with an alkali and does not impart viscosity or thixotropy to the ink, and is a widely used acrylic resin. It is an emulsion. As the non-alkali thickening type and / or hardly alkaline thickening type acrylic resin emulsion, commercially available ones can be used. For example, JSRAE116 and AE
120, AE125, AE166 (all manufactured by Nippon Synthetic Rubber Co., Ltd.), John Krill 780, 7001 and 6
32, 352, and 74J (all manufactured by Johnson Polymer Co., Ltd.) and the like. The non-alkali thickening type and / or hardly alkaline thickening type acrylic resin emulsion is 2.5 to 15.0% by weight in the ink composition, preferably 5.0.
It is used in the range of up to 10.0% by weight.

When the water-based ink composition for a writing instrument of the present invention is applied to a ball-point pen of a type in which ink is directly accommodated in an ink accommodating tube having a tip attached directly or through a connecting member, a shear thinning viscosity imparting agent is used. The addition gives the ink an appropriate viscosity for practical use. The shear thinning agent used can be appropriately selected from those conventionally known, and specific examples thereof include polysaccharides such as xanthan gum, succinoglycan, and carrageenan, polyacrylic acid, crosslinked acrylic acid, polyvinylacetamide. , Nonionic surfactants, anionic surfactants, associative urethane emulsions and the like.

In addition to the above components, if necessary, inorganic salts such as sodium carbonate, sodium phosphate, sodium acetate, etc., pH adjusting agents such as organic basic compounds such as water-soluble amine compounds, benzotriazole, tolyltriazole, dicyclohexyl ammonium. Rust inhibitors such as nitrite, diisopropylammonium nitrite, saponin, carboxylic acid, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,
Antiseptic or antifungal agent such as 3,5,6-tetrachloro-4- (methylsulfonyl) pyridine, metal soap, polyalkylene glycol, fatty acid ester, ethylene oxide addition type cationic activator, phosphoric acid activator, thiocarbamine Acid salts, lubricants such as dimethyldithiocarbamate, wetting agents such as urea and sodium pyrophosphate, defoaming agents,
A dispersant, a fluorochemical surfactant or a nonionic surfactant that improves the permeability of the ink may be used.

The water-based ink composition for a writing instrument of the present invention is not particularly limited in structure and shape of the ballpoint pen itself, and a general-purpose one can be applied from the past. 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 effective in the past, and the vicinity of the tip of a metal pipe is inward from 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.

As the ink containing tube containing the ink composition, for example, a molded body 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 containing tube 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 retractable mechanism that is housed 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.

[0026]

EXAMPLES The effects of the present invention will be specifically described below based on Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, the number of "part" of each component represents "part by weight". Example 1 40.0 parts of carbon black aqueous dispersion [trade name: SP Black 8922, manufactured by Fuji Dye Co., Ltd .; pigment: 20% by weight, diethylene glycol: 15% by weight, anionic surfactant: 6% by weight, water: Remainder] Ethylene glycol 10.0 parts Diethylene glycol 5.0 parts Triethanolamine 1.0 part Alkali thickening acrylic emulsion 2.2 parts [Product name: Primal ASE-60, manufactured by Rohm and Haas Co.] Urea 5.0 parts Phosphate ester-based surfactant 0.5 part [Product name: PRYSURF AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] Reduced starch saccharified product 10.0 parts [Product name: HS-20, manufactured by Hayashibara Co., Ltd .; Sugar solid content / about 70%] Non-alkali thickening type acrylic resin emulsion 5.0 parts [Product name: John Cryl 780, Johnson Polymer Co., Ltd. Solid content, about 48%, average particle diameter 0.1 μm] 1,3 diethylthiourea (rust inhibitor) 0.3 part 1,2-benzthiazolin-3-one 0.2 part [preservative, trade name : Proxel XL-2, manufactured by Avicia Co., Ltd.] Water 20.8 parts Components other than the pigment are mixed and pre-stirred, then the pigment (water dispersion) is added, the mixture is stirred at 2000 rpm for 10 minutes with a disperser, and an aqueous black for ballpoint pen I got ink.

Example 2 Aqueous dispersion of carbon black 50.0 parts [trade name: WA Black A250, manufactured by Dainichiseika Kogyo KK; pigment 15% by weight, diethylene glycol 20% by weight, acrylic resin 6% by weight , Water / balance] Glycerin 5.0 parts Ethylene glycol 5.0 parts Associative urethane resin 2.5 parts [Product name: TAFIGEL PUR60, manufactured by Munjinchem] Butyl carbitol 0.5 parts Phosphate ester surfactant 0 .5 parts [trade name: Prysurf AL, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.] triethanolamine 0.1 part reduced starch saccharified product 10.0 parts [trade name: HS-30, manufactured by Hayashibara Co., Ltd., sugar Solid content / about 70%] 1,3 Diethylthiourea (rust inhibitor) 0.3 part 1,2-benzthiazolin-3-one 0.2 part [preservative, trade name: Proxe XL-2, manufactured by Avicia Co., Ltd.] Water 25.9 parts TAFIGEL PUR60 and butyl carbitol are mixed in advance, components other than the pigment are mixed, and after preliminary stirring, the pigment (aqueous dispersion) is added and the mixture is dispersed by a disper. 2000 rp
The mixture was stirred for 10 minutes to obtain an aqueous black ink for a ballpoint pen.

Example 3 Copper Phthalocyanine Blue Water Dispersion 50.0 parts [trade name: SP Blue 625, manufactured by Fuji Dye Co., Ltd .; pigment: 27.5% by weight, diethylene glycol: 8% by weight, anionic surfactant: 4 wt%, water / balance] Ethylene glycol 15.0 parts Triethanolamine 1.0 part Alkali thickening acrylic emulsion 2.2 parts [Product name: Primal ASE-60, manufactured by Rohm and Haas Co.] Urea 5.0 Part Phosphate ester type surfactant 0.5 part [trade name: PRYSURF A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.] reduced starch saccharified product 10.0 parts [trade name: HS-20, manufactured by Hayashibara Co., Ltd. ; Sugar solid content / about 70%] 1,3 Diethylthiourea (rust inhibitor) 0.3 part 1,2-benzthiazolin-3-one 0.2 part [preservative, trade name: Proxe XL-2, manufactured by Avicia Co., Ltd.] Water 15.8 parts Components other than the pigment are mixed and pre-stirred, then the pigment (water dispersion) is added, and the mixture is stirred at 2000 rpm for 10 minutes with a disper to obtain an aqueous blue ink for a ballpoint pen. Obtained.

Example 4 C. I. Direct black 19 aqueous solution 40.0 parts [Product name: Water Black 100L, manufactured by Orient Chemical Industry Co., Ltd .; dye 20% by weight, water 80% by weight] Glycerin 10.0 parts Diethylene glycol 10.0 parts Xanthan gum 0.4 Parts Urea 10.0 parts Phosphate ester surfactant 0.5 parts [Product name: Prysurf A212C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.] Triethanolamine 0.2 parts Reduced starch saccharified product 10.0 parts [ Product name: HS-30, manufactured by Hayashibara Co., Ltd .; sugar solid content / about 70%] 1,3 diethylthiourea (rust inhibitor) 0.5 part 1,2-benzthiazolin-3-one 0.5 part [ Preservative, trade name: Proxel XL-2, manufactured by Avicia Co., Ltd.] Water 17.9 parts The above components are mixed and stirred with a disper at 6000 rpm for 10 minutes to prepare a black ballpoint pen for water. A colored water-based ink was obtained.

Comparative Example 1 The HS-20 in the composition of Example 1 was replaced with the same amount of water,
In the same manner as in Example 1, an aqueous black ink for ballpoint pen of Comparative Example 1 was obtained.

Comparative Example 2 The HS-30 in the composition of Example 2 was replaced with the same amount of water,
A water-based black ink for ballpoint pens of Comparative Example 2 was obtained in the same manner as in Example 2.

Comparative Example 3 HS-20 in the composition of Example 3 was replaced with the same amount of water,
A water-based blue ink for ballpoint pens of Comparative Example 3 was obtained in the same manner as in Example 3.

Comparative Example 4 The HS-30 in the composition of Example 4 was replaced with the same amount of water,
A water-based black ink for ballpoint pens of Comparative Example 4 was obtained in the same manner as in Example 4.

Comparative Example 5 A water-based black ink for ballpoint pens of Comparative Example 5 was obtained in the same manner as in Example 1, except that HS-20 in the composition of Example 1 was replaced with the same amount of glycerin.

Comparative Example 6 In the same manner as in Example 3, HS-20 in the composition of Example 3 was replaced with the same amount of anhydrous crystalline maltose to obtain an aqueous blue ink for a ballpoint pen of Comparative Example 6.

COMPARATIVE EXAMPLE 7 HS-20 in the composition of Example 1 was replaced with the same amount of reduced maltose (maltitol) to obtain an aqueous black ink for a ballpoint pen of Comparative Example 7 in the same manner as in Example 1.

Example 1 obtained by the above formulation and preparation method
4 to 4 and Comparative Examples 1 to 7, the inks of 0.
A stainless steel ball-point pen tip holding a 5 mm diameter cemented carbide ball is directly filled in an ink containing tube fitted at one end, and an ink backflow preventer, which is a highly viscous fluid, is placed at the rear end of the ink. A sample ballpoint pen was created and the following performance comparison tests were conducted.

Cap-off test After assembly, a sample ball-point pen confirmed to be able to write normally was left in the room and in a thermostatic chamber at 50 ° C. for 60 days with the pen tip exposed, and then JISP3201.
The character “correct” was handwritten on the writing paper A, and it was examined from which character the normal writing was possible and evaluated according to the following criteria. Good: Can write normally from the first character. Δ: Normal writing is possible within 20 characters. X: 20 characters or more cannot be written normally.

The sample ball-point pen with the hanging test cap removed is used as a pen tip (tip).
After being held in a non-contact state downward (inverted) and left in an atmosphere of a temperature of 20 ° C. and a relative humidity of 95% for 20 hours, the appearance of the pen tip was visually observed and evaluated according to the following criteria. ◯: No ink leakage (dripping) is observed. Δ: Ink droplets are recognized at the tip of the chip. ×: A large ink droplet is recognized at the tip of the tip, or ink leaked from the tip of the tip is falling.

The results of the performance comparison test are shown in the table below.

[0041]

[Table 1]

[0042]

An object of the present invention is to provide a water-based ink composition for a writing instrument containing a reduced starch saccharified product as a cap-off property-imparting agent. Of drooping under high humidity conditions that occurred in ink compositions containing a water-soluble organic solvent, and adverse effects on ink due to decomposition of ureas at high temperatures in ink compositions containing urea and / or urea derivatives. It is possible to solve the problems and obtain a writing instrument having good stability, excellent cap-off property, and drooping resistance.

Claims (8)

[Claims] 1. An aqueous ink composition for a writing instrument, which comprises at least a colorant, water, and a reduced starch saccharified product. 2. The saccharified product of reduced starch comprises reduced starch syrup and / or reduced branched oligosaccharide.
The water-based ink composition for a writing instrument as described in 1. 3. The writing instrument according to claim 1, wherein the saccharified product of reduced starch is blended in the range of 2.0 to 20.0% by weight with respect to the total amount of the ink composition. Water-based ink composition for use. 4. 60 to 80% by weight of the reduced starch saccharified product
Is a polysaccharide of 4 to 8 sugars, and the water-based ink composition for a writing instrument according to any one of claims 1 to 3. 5. The water-based ink composition for a writing instrument according to claim 1, which comprises a non-alkali thickening type and / or hardly alkaline thickening type acrylic resin emulsion. 6. The non-alkali thickening type and / or hardly alkaline thickening type acrylic resin emulsion is blended in a range of 2.5 to 15.0% by weight with respect to the total amount of the ink composition. The water-based ink composition for a writing instrument according to claim 5. 7. A water-based ink composition for a writing instrument, wherein the water-based ink composition for a writing instrument according to any one of claims 1 to 6 is an ink for a water-based ball-point pen to which a shear thinning agent is added. 8. The water-based ink for a writing instrument according to claim 7, wherein the water-based ball-point pen has a structure in which ink is directly contained in an ink-accommodation tube attached with a ball-point pen tip directly or via a connecting member. Composition.