JP2002235025A - Ink composition for ball-point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous ink composition for ball-point pens, having excellent stability with time, exhibiting excellent writing performances without causing blur, or the like, when applied to a ball-point pen having a mechanism of directly charging an ink to a storage pipe and used for writing. SOLUTION: This aqueous ink composition for ball-point pens comprises a dye, water, a particulate dispersant and any of a polyether-based, a urethane modified polyether-based and a polyaminoplastol ether-based associative thickeners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water-based ink composition for a ballpoint pen. More specifically, the present invention relates to a water-based ink composition for ballpoint pens exhibiting shear thinning.

[0002]

2. Description of the Related Art Conventionally, the ink contained therein exhibits a high viscosity and is stably held in a ball-point pen mechanism at the time of standing where no shear stress is applied, and near the ball due to the shear stress generated by the rotation of the ball during writing. Xanthan gum has been disclosed as a shear-thinning agent to be added to an aqueous ink composition contained in a ballpoint pen of a type that reduces the viscosity and transfers the reduced-viscosity ink to a paper surface (Japanese Patent Laid-Open No. 59-74175).

[0003]

The present invention has been further studied on a novel shear-thinning agent to be added to an aqueous ink composition for a ballpoint pen, and it has been found that a specific associative thickener is incorporated into the ink. The present inventors have found that a smooth writing feeling can be obtained, and a shear-thinning ink composition showing good performance in various writing performances can be obtained, and the present invention has been completed.

[0004]

The present invention provides an ink composition comprising at least a dye, water, a particulate dispersion, and an associative thickener, wherein the associative thickener is a polyether. Aqueous ink composition for a ballpoint pen, which is one of a urethane-modified polyether-based, polyaminoplastol ether-based associative thickener, or at least a pigment,
Water, and an ink composition comprising an associative thickener,
A water-based ink composition for a ballpoint pen is required, wherein the associative thickener is any of a polyether-based, urethane-modified polyether-based, and polyaminoplastol ether-based associative thickener. Furthermore, 100r by E-type rotational viscometer
Ink viscosity at pm is 20 to 300 mPa · s
(20 ° C.) and a shear thinning index of 0.1 to
It is required to indicate 0.7.

As described above, the present invention relates to a polyether type,
It is a water-shrinkable aqueous ballpoint pen ink containing any one of a urethane-modified polyether-based and a polyaminoplastol ether-based associative thickener, and a ballpoint pen that satisfies good writing performance by containing the ink. Is obtained based on the new finding that
The associative thickener is particularly suitable for application of an ink composition using a pigment as a coloring agent, and aggregation of a pigment which is likely to occur in an ink composition using a polysaccharide such as xanthan gum as a shear-thinning agent. Therefore, an ink composition having good ink ejection and good handwriting density can be obtained. In addition, the aforementioned polyether-based, urethane-modified polyether-based, and polyaminoplastol ether-based associative thickeners are different from alkali-swellable or alkali-soluble thickeners, and are affected by the pH of the ink. As a result, it has excellent practicality and can provide stable shear thinning.

A solution in which the associative thickener is dispersed or dissolved does not cause a change in viscosity due to a change in shear rate, but when hydrophobic particles such as pigments and emulsions are present in the solution, the associative thickener is dispersed. Since the hydrophobic group of the agent is adsorbed on the particle surface and the hydrophilic group of the associative thickener is associated by intermolecular force or hydrogen bond, the granular material and the associative thickener form a three-dimensional network structure and are high. Indicates viscosity. Further, it is presumed that when a strong shearing force acts, adsorption and association are desorbed / separated, and the three-dimensional network structure is temporarily weakened to exhibit low viscosity, that is, so-called shear thinning.

Among the above-mentioned associative thickeners, examples of the polyether-based associative thickener include compounds represented by the following general formula (1):

Embedded image (However, R represents an aliphatic hydrocarbon or an aromatic hydrocarbon, and m represents an integer of 100 or more.) Emanone 3199, 3299, 3299R [manufactured by Kao Corporation, trade name], Emulmin 862 [Sanyo Chemical Co., Ltd. Nikor CS-600P [Nikko Chemicals Co., Ltd., trade name], SN Thickener 60
1, 616, A801, A806, A816 (manufactured by San Nopco Co., Ltd., trade name), Leolate 300, 3
10, 350 (manufactured by Elementis Japan, trade name), etc. can be used.

Examples of the urethane-modified polyether-based associative thickener include compounds represented by the following general formula (2):

Embedded image (However, R represents an aliphatic hydrocarbon or an aromatic hydrocarbon, and m and n each represent an integer of 1 or more.) SN thickeners 603, 607, 612, and A80
3, A804, A812, A814 (manufactured by San Nopco Co., Ltd., trade name), Primal RM-8W, RM8
25, RM2020NPR, SCT-275 (manufactured by Rohm and Haas Co., Ltd., trade name), Koraclar PU7
5, PU85 (manufactured by BASF, trade name), Leorate 210, 216, 244, 255, 266, 278, 288 (manufactured by Elementment Japan, trade name), TAFIGEL PUR series (Munzinchem Co., Ltd.) DK Thickener Series (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), ADEKA NOL UH Series (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), and the like.

Examples of the polyaminoplastol ether-based associative thickener include compounds represented by the following general formula (3):

Embedded image (However, R ₁ represents hydrogen _, an alkyl group having 1 to 4 carbon atoms, an acyl group having 1 to 4 carbon atoms, R ₂ represents a divalent alkylene oxide, m and n each represent an integer of 1 or more, Am
p represents an aminoplastol group skeleton residue represented by the formula (4),

Embedded image R ₃ represents an alkyl group having 2 or more carbon atoms.) OPTIFLO L series, M series, and H series (manufactured by Nissan Sudohemie, trade name) can be used. The associative thickener described above is used in the ink composition at 0.1%.
-4% by weight, preferably 0.5-2% by weight.
If the amount is less than 0.1% by weight, it is difficult to impart a desired shear thinning property. If the amount exceeds 4% by weight, the viscosity of the ink becomes high, and particles such as pigments contained in the ink tend to show aggregation tendency. Therefore, a problem may occur in ink ejection.

As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof are shown below. As the dye, an acid dye, a basic dye, a direct dye, or the like can be used.
As the acid dye, Newcoccin (C.I.
5), 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.
I. 42755), naphthalene green (CI.44)
025), Eosin (CI. 45380), Phloxine (CI. 45410), Erythrosin (CI.
5430), nigrosine (CI. 50420), acid flavin (CI. 56205) and the like.

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

As the direct dye, Congo Red (C.I.
I. 22120), Direct Sky Blue 5B (C.I.
I. 24400), Violet BB (CI. 279)
05), direct deep black EX (CI.3
0235), Kayalas Black G Conch (CI.35
225), Direct Fast Black G (CI.3)
5255), phthalocyanine blue (CI. 7418)
0) etc. are used.

As the pigment, inorganic pigments such as carbon black and ultramarine blue, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as a surfactant and a water-soluble resin, which are finely and stably dispersed in an aqueous medium. Dispersed water-dispersed pigment products and the like are used. Examples of the water-dispersed pigment using a surfactant include C.I. I. Pigment 15:
3B [trade name: S.I. S. Blue GLL, pigment content 24
%, Sanyo Dyeing Co., Ltd.], C.I. I. Pigment
Red 146 [trade name: S.I. S. Pink FBL,
Pigment content 21.5%, Sanyo Dyeing Co., Ltd.], C.I. I. Pi
gment Yellow 81 [Product name: TC Ye
llowFG, pigment content about 30%, Dainichi Seika Kogyo Co., Ltd.
C.), C.I. I. Pigment Red 220/166
[Trade name: TC Red FG, pigment content: about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.]. Examples of the water-dispersible pigment using a water-soluble resin include C.I. I. Pig
ment Black 7 [Product name: WA color]
Black A250, pigment content 15%, manufactured by Dainichi Seika Kogyo Co., Ltd.], C.I. I. Pigment Green 7
[Product name: WA-S color Green, pigment content 8
%, Manufactured by Dainichi Seika Kogyo Co., Ltd.], C.I. I. Pigment
Violet 23 [trade name: Micro Pigmo WM
VT-5, pigment content 20%, Orient Chemical Industry Co., Ltd.
C.), C.I. I. Pigment Yellow 83
[Product name: Emmacol NS Yellow 4618, pigment content 3
0%, manufactured by Sanyo Dyeing Co., Ltd.], and a fluorescent pigment in the form of fine particles of a synthetic resin in which various fluorescent dyes are made into a solid solution in a resin matrix can be used. In addition, pearl pigments, metal powder pigments, luminous pigments, titanium dioxide, silica,
Examples thereof include a white pigment such as calcium carbonate, a capsule pigment containing a thermochromic composition, and a capsule pigment containing a fragrance or a fragrance. The colorants may be used alone or as a mixture of two or more, and are used in the ink composition in an amount of 1 to 25% by weight, preferably 2 to 15% by weight.

When a dye is used as the colorant, it is necessary to add a particulate dispersion to the ink composition. Examples of the dispersion include a filler such as silica, benzoguanamine, and polymethyl methacrylate. Resin particles, resin emulsions, emulsions of waxes and fragrances,
A lubricant emulsion can be exemplified.

Water is used as the solvent, but if necessary, a water-soluble organic solvent compatible with water can be added. As the water-soluble organic solvent, for example, 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-
Pyrrolidone, N-methyl-2-pyrrolidone and the like. The water content is 10 to 80% by weight, preferably 20% by weight.
It is used in the range of ~ 75% by weight. Further, the water-soluble organic solvent may be used alone or in combination of two or more,
It is used in the range of 2 to 60% by weight, preferably 5 to 35% by weight.

Also, alkyd resins as water-soluble resins,
One or more of acrylic resin, styrene-maleic acid copolymer, cellulose derivative, polyvinylpyrrolidone, polyvinyl alcohol, dextrin and the like can be used for adhesion to paper and for imparting viscosity.

In addition, if necessary, inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, Rust inhibitors such as diisopropylammonium nitrite and saponin;
-Sodium salt of benzthiazolin 3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-
Preservatives or fungicides such as tetrachloro-4- (methylsulfonyl) pyridine, metal soaps, polyalkylene glycols, fatty acid esters, ethylene oxide addition type cation activators, phosphoric acid activators, thiocarbamate, dimethyldithiocarbamic acid Lubricant such as salt, urea, nonionic surfactant, sorbit, mannitol, sucrose, glucose, reduced starch hydrolyzate, wetting agent such as sodium pyrophosphate, defoamer, dispersant, ink permeability A fluorine-based surfactant or a nonionic surfactant which is improved may be used.

In addition to the associative thickener, a compound that imparts shear thinning properties can be used in combination. Examples of the compound that imparts shear thinning properties include xanthan gum, welan gum, succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose (average molecular weight of about 1 to 8 million), guar gum, locust bean gum and Derivatives, hydroxyethylcellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 mainly containing alkyl esters of methacrylic acid, and gelling ability extracted from seaweeds such as glycomannan, agar and carrageenin. Viscous polysaccharides, benzylidene sorbitol and benzylidene xylitol or derivatives thereof, crosslinkable acrylic acid polymer, 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
To 12 nonionic surfactants, salts of dialkyl or dialkenyl sulfosuccinic acid. Examples thereof include a mixture of N-alkyl-2-pyrrolidone and an anionic surfactant, and a mixture of polyvinyl alcohol and an acrylic resin.

In the ink composition of the present invention, under a high shear stress during writing, the three-dimensional structure is temporarily weakened to lower the viscosity of the ink, and the ink near the ball becomes a low-viscosity ink suitable for writing. It moves in the gap between the ball house and the ball house by capillary force and is transferred to the paper surface. At the time of non-writing, the viscosity of all the inks including the vicinity of the ball becomes high, so that it is possible to prevent the leakage of the ink, the separation of the ink and the backflow. In addition, the physical properties of the ink can be kept stable over time.

For the structure of the writing tip (tip) of the ball-point pen filled with the ball-point pen-based water-based ink, a general-purpose mechanism has been conventionally effective, and the vicinity of the tip of the metal pipe is pressed and deformed inward from the outer surface. A chip holding a ball in a ball holding portion, or a chip holding a ball in a ball holding portion formed by cutting a metal material with a drill or the like, or a metal pipe or metal material In this case, a ball held by a chip formed by the above cutting process and urged forward by a spring body can be applied. Further, the ball having a diameter of about 0.3 to 1.2 mm, such as a cemented carbide, stainless steel, ruby, or ceramic, can be used.

The ink container for accommodating the ink and the ink backflow preventer is preferably made of a molded article made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate or the like, in terms of low ink evaporation and productivity. Used. In addition, the ink storage tube is 2.5 to 10
Those having an inner diameter of mm are preferably used. Further, by using a transparent, colored transparent, or translucent molded body as the ink storage tube, the ink color, the remaining amount of the ink, and the like can be confirmed. In addition to directly connecting the chip to the ink storage tube, the ink storage tube and the chip may be connected via a connection member. In addition, the ink storage tube may be one in which the refill is stored in a shaft cylinder as a form of a ballpoint pen refill, or the shaft cylinder itself having a tip attached to a tip as an ink container may be inserted in the shaft cylinder. The ink may be directly filled. The inner diameter of the refill housed in the barrel is:
Those having a diameter of 2.5 to 5 mm are preferably used, and those having a diameter of 4 to 10 mm are preferably used as the inner diameter of a shaft cylinder for directly storing ink.

Examples of the ink backflow preventer include non-volatile media such as polybutene and silicone oil. If desired, silica, aluminum silicate and the like can be added to the medium.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The water-based ink for a ball-point pen of the present invention is prepared by adding a colorant and various additives to a solvent, and then adding an associative thickener. It is put into practical use in a so-called straight liquid state, which is directly filled in the housing tube.

[0024]

EXAMPLES The ink composition of the present invention and the ink composition of the comparative example, and the ink at 1 ° C. and 10 rpm at 20 ° C. measured with an EMD type rotational viscometer and an ELD type rotational viscometer,
Viscosity at 100 rpm (viscosity at 1 rpm of Examples 1 and 2 and Comparative Examples 1 and 2 and 10
The viscosities at rpm and 100 rpm were measured using an ELD rotational viscometer, and the others were measured using an EMD rotational viscometer). Numerical values indicating the composition in the table indicate% by weight.

[0025]

[Table 1]

[0026]

[Table 2]

The contents of the raw materials in the table will be described along the note numbers. (1) Shinroihi Chemical Co., Ltd., emulsion polymerization type fluorescent pigment (2) Dainichi Seika Kogyo Co., Ltd., carbon black dispersion (solid content: 15%) (3) Orient Chemical Co., Ltd., C . I. Acid
(Yellow42S) (4) Munjinchem, urethane-modified polyether-based associative thickener, active ingredient 40%, butyltriglycol suspension (5) Kao Corporation, polyether-based associative thickener (6) ) Nissan Sudohemie, polyaminoplastol ether-based associative thickener, active ingredient 40%, butyl diglycol solution (7) Nippon Kyrest Co., trade name: Kires Coat B (8) Hokuko Sangyo Co., trade name: Hokuside R150 (9) Permachem Asia, Product name: Topside 2
80, 2-pyridinethiol-1-oxide sodium salt (10) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Plysurf A212E, phosphate ester surfactant (11) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Trade name: Plysurf A215C, phosphate ester surfactant (12) Sannopco Co., Ltd., trade name: Dehydran 16
20 (13) Kanebo NSC, product name: Kanebinol K
D5 (14) Dainippon Pharmaceutical Co., Ltd.

The ink compositions of Examples and Comparative Examples are prepared by adding a colorant and an additive to a solvent and stirring the mixture, and further adding a thickener and stirring the mixture. The ink composition of Comparative Example 3 was excluded from the following performance tests because it did not show shear thinning.

Dispersion stability test The initial stage of the inks of the Examples and Comparative Examples, and 3 at 50 ° C.
The state after standing for 0 days was observed with a microscope.

Preparation of Ballpoint Pen According to the ink preparation method, inks of Examples 1 to 3 and Comparative Examples 1 and 2 were prepared, and a stainless steel tip holding a ball having a diameter of 0.5 mm was attached to one end of a polypropylene pipe. Fill the fitted ballpoint pen refill,
Further, after filling the ink backflow preventive body in close contact with the rear end face of the ink, the ballpoint pen refill was incorporated into a shaft cylinder to obtain a ballpoint pen.

Writing test Initial ballpoint pen obtained as described above and 50 ° C.
Was written on paper with a ballpoint pen left for 30 days, and the handwriting was visually observed. The results are shown below.

[0032]

[Table 3]

The evaluation of each test result in the table is as follows. Dispersion stability test ：: Particles are uniformly dispersed. Δ: Particles form aggregates of 1 μm or less. ：: Particles form aggregates exceeding 1 μm. ×: Aggregated particles settled. Writing test ：: Good handwriting is obtained. Δ: Blurring or line cracking occurs at the beginning of writing or during writing. ×: Cannot be written.

[0034]

The present invention is an aqueous ink composition for a ballpoint pen containing a polyether-based, urethane-modified polyether-based, or polyaminoplastol ether-based associative thickener as a shear-thinning agent. Excellent stability over time. Further, when the present invention is applied to a ball-point pen having a mechanism of directly filling the ink into the storage tube and writing is performed, a ball-point pen exhibiting good writing performance without causing blurring or the like can be provided.

Claims (3)

[Claims] 1. An ink composition comprising at least a dye, water, and a particulate dispersion, and an associative thickener,
An aqueous ink composition for a ballpoint pen, wherein the associative thickener is any of a polyether-based, urethane-modified polyether-based, and polyaminoplastol ether-based associative thickener. 2. An ink composition containing at least a pigment, water, and an associative thickener, wherein the associative thickener is a polyether-based, urethane-modified polyether-based, or polyaminoplastol ether-based associative thickener. A water-based ink composition for a ballpoint pen, which is one of thickeners. 3. 100 rpm by an EMD type rotational viscometer.
Ink viscosity at 20 to 300 mPa · s (20
C.) and a shear thinning index of 0.1 to 0.7.