JP2005132885A - Water-based ink composition for ballpoint pen and water-based ballpoint pen filled with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based ink composition for ballpoint pens which is excellent in cap-off performance and resistance against ink oozing and storage-stable and a ballpoint pen filled with the ink composition. <P>SOLUTION: The water-based ink composition for ballpoint pens is obtained by mixing a colorant, water, a water-soluble polymer, a water-soluble solvent, and one kind or more than one kind selected from L-ascorbic acid, ascorbic acid derivatives, erysorbic acid and/or their salt as indispensable ingredients. The viscosity of the ink at 20°C as measured by using a B-type rotational viscometer equipped with a BL adaptor is 5-20 mPa×s. The ballpoint pen filled with the ink composition is presented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a water-based ink composition for ballpoint pens and a water-based ballpoint pen incorporating the same. More specifically, when applied to a ballpoint pen with a structure in which ink is directly stored in an ink storage tube with a ballpoint pen tip attached to one end, it has excellent sag prevention performance without impairing dry-up resistance at the pen tip. The present invention relates to a water-based ink composition for ballpoint pens and a water-based ballpoint pen.

Conventionally, as a ballpoint pen containing a water-based ink composition, ink is impregnated into an ink occlusion body in which a fiber converging body is covered with a synthetic resin film, etc., and the ink is led to a chip with an ink induction core in which fibers are bound with resin. Structure, an ink supply member (pen core) that adjusts the ink supply amount between the ink containing part directly filled with ink and the ballpoint pen tip, or a ballpoint pen tip is fitted directly or via a relay member to one end In general, a structure in which ink is directly stored in the ink storage tube is provided for practical use.
Among these, in ballpoint pens using ink supply members, air enters and exits as the internal pressure changes in the ink container due to ink consumption and temperature changes, but when the internal pressure changes significantly, the ink button May cause falling or sagging.

In addition, in ballpoint pens that store ink directly in the ink storage tube and lead the ink directly to the chip without going through the ink supply member, etc. When the ink viscosity is low and the ink viscosity is low, the ink ejection property is excellent and good writing quality is provided. On the other hand, the ink may sag when left in the pen point downward state. In particular, when a ballpoint pen is used that does not have a cap, etc. and the pen tip is always exposed to the outside air and is housed in the shaft cylinder, moisture evaporation from the pen tip is significant and writing is impossible in a short time. Therefore, it is necessary to add an additive to the ink for the purpose of improving the dry-up resistance. However, when a large amount of a water-soluble organic solvent, a wetting agent such as polyhydric alcohol, urea, or the like is added as the additive in order to satisfy dry-up resistance, the ink viscosity is increased and writing defects are likely to occur. In some cases, there are problems such as that the ink does not dry for a long time, or that the pen tip easily hangs down when left in the pen tip downward state.
Japanese Patent Publication No. 5-54875

  The present invention solves the above-described conventional problems, that is, a ball-point pen that exhibits excellent sag-preventing performance without impairing dry-up resistance, and has less blur of handwriting even in low-viscosity inks. Another object of the present invention is to provide a water-based ink composition and a ballpoint pen incorporating the same.

The present invention is at least one selected from colorants, water, water-soluble polymers, water-soluble organic solvents, L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or their salts, or two or more thereof. The viscosity of the ink at 20 ° C. is 5 to 20 mPa · s as measured by a B-type rotational viscometer using a BL adapter.
Further, any one or two or more selected from the above L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or their salts are contained in an amount of 0.05 to 2.0% by weight based on the total amount of the ink composition. The water-soluble polymer is λ-carrageenan, the λ-carrageenan is contained in an amount of 0.05 to 0.5% by weight based on the total amount of the ink composition, and the colorant is a dye. It is a requirement.
Further, the water-based ink composition for a ballpoint pen is directly filled into an ink containing tube having a ballpoint pen tip attached to one end or via a connecting member, and an ink backflow prevention body is closely disposed on the rear end surface of the ink composition. A water-based ballpoint pen is required.

INDUSTRIAL APPLICABILITY The present invention can provide a water-based ink composition for ballpoint pens that has both a drooping prevention effect and a cap-off effect and excellent writing performance. In addition, since L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or their salts used in the present invention also have the property of absorbing oxygen in the liquid, the ink is deteriorated due to oxidation or the generation of bubbles. The poor writing phenomenon can be prevented.
Furthermore, the ball-point pen excellent in the writing performance and the preservation | save performance which incorporated the said ink composition for ball-point pens can also be provided.

The water-based ink composition for a ballpoint pen of the present invention is directly filled into an ink containing tube in which a ballpoint pen tip is attached directly or via a connecting member, and an ink backflow preventer is closely disposed on the rear end surface of the ink composition. When it is applied to a water-based ballpoint pen, it is most effective.
Conventionally, inks applied to this type of ballpoint pen have been generally added with shear thinning agents such as xanthan gum, guar gum, and welan gum. However, these shear thinning agents are strong when dried. There is a tendency to form a high film. Therefore, when the ballpoint pen containing the ink containing the shear thinning agent is left for a long time with the tip exposed, the shear thinning agent is dried at the tip of the tip to form a hard film. For this reason, there were problems such as fading at the beginning of writing and inability to write.

  Compared to ballpoint pens using low-viscosity inks, ballpoint pens using inks containing these shear-thinning agents add “crying” or “bottoms” that are characteristic of medium- and high-viscosity inks when writing. As a result, a clear writing line cannot be obtained, and ink accumulates at the tip of the chip during writing, resulting in poor appearance.

  Therefore, in order to obtain good writing performance without cap-off properties and “crying out” and “bottom”, no shear thinning agent is added and the shear thinning effect is low or shear thinning does not occur. It is preferable to add a water-soluble polymer to make the ink have a low viscosity. Specifically, both cap-off property and writing performance can be improved by adjusting to 5 to 20 mPa · s by measurement with a B-type rotational viscometer using a BL adapter at 20 ° C.

Examples of the water-soluble polymer that has low shear thinning effect or does not exhibit shear thinning viscosity include cellulose derivatives such as λ-carrageenan, methylcellulose, carboxymethylcellulose, and hydroxypropylmethylcellulose, polyvinylpyrrolidone, polyvinyl alcohol, and polyethylene oxide. .
The water-soluble polymer is effectively added in an amount of 0.05 to 0.5% by weight, preferably 0.05 to 0.3% by weight, more preferably 0.05 to 0.2% by weight, based on the total amount of ink. Is added.
If it is less than 0.05% by weight, the dripping prevention performance and ink bleeding prevention effect are not satisfactory, and if it exceeds 0.5% by weight, the viscosity of the ink becomes too high. Occur.

  Among the water-soluble polymers, λ-carrageenan has been found to have a significantly improved cap-off property compared to other water-soluble polymers. Addition of the λ-carrageenan effectively prevents dripping when the ballpoint pen is left down without extremely increasing the viscosity of the ink. Excellent properties of writing well.

  In the case of a ballpoint pen directly filled with low-viscosity ink, bubbles may be generated in the ink tank due to impact during transportation or dropping, or evaporation of water due to heating. Even if there are only a few bubbles at the beginning, the heated state continues, or even if it is at room temperature, the standing period is prolonged, which causes the bubbles to further expand and block the ink passage, and the ink is ejected. is there. Therefore, it is important to remove bubbles in the ink.

  As a result of various investigations on bubble removing agents effective for low-viscosity inks, L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or their salts were most effective. L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or their salts are known as reducing agents, but they absorb oxygen and prevent the oxidation of substances that coexist in the surroundings by gradually decomposing ascorbic acids themselves To do. It is a compound that exhibits a slightly high reactivity in this way, and causes problems such as aggregation and precipitation of reaction products with other components in the ink, particularly shear thinning agents, pigments, etc. In some cases, however, the combination with the λ-carrageenan of the present invention is stable. In particular, no deterioration was observed in the ink using a dye as the colorant.

  The L-ascorbic acid, ascorbic acid derivative, erythorbic acid and / or their salts may be used alone or in combination of two or more, but added in an amount of 0.05 to 2.0% by weight based on the total amount of the ink. The An addition amount of 0.05 to 2.0% by weight is effective, but preferably 0.05 to 1.0% by weight, more preferably 0.05 to 0.5% by weight. If the amount is less than 0.05% by weight, the effect of removing bubbles is not recognized. If the amount exceeds 2.0% by weight, discoloration of the ink may be significant, or an insoluble matter may be generated due to reaction with other components in the ink.

  Among the L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or their salts, erythorbic acid and / or its salts have the highest effect of removing bubbles, and the ink can be used even in a high temperature atmosphere or after standing for a long time. It is optimally used because it produces the least amount of discoloration and reaction products.

In the water-based ink composition of the present invention, resin fine particles and / or a wax emulsion may be used in combination in order to further enhance the dripping prevention effect. The resin fine particles are a single monomer polymer or a copolymer of two or more monomers and do not dissolve in an aqueous medium.
The wax emulsion is an aqueous dispersion of vegetable wax such as carnauba wax, mineral wax such as montan wax, animal wax such as lanolin wax, petroleum natural wax such as paraffin wax, and synthetic wax.
The resin fine particles and / or wax emulsion is used in the range of 0.5 to 5.0% by weight based on the total amount of the ink composition. If it is less than 0.5% by weight, no dripping prevention effect is observed. If it exceeds 5.0% by weight, a strong film is formed at the tip of the tip when left in a cap-off state, thus preventing ink dripping. Although the effect is sufficient, the dry-up resistance performance is inferior.

As the colorant used in the present invention, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof are illustrated below.
As the dye, an acid dye, a basic dye, a direct dye, or the like can be used.
As an acid dye,
New coccin (CI. 16255),
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. 44025),
Eosin (C.I. 45380),
Phloxin (C.I. 45410),
Erythrosine (C.I. 45430),
Nigrosine (C.I. 50420),
Acid flavin (C.I. 56205) or the like is used.

As basic dye,
Chrysoidine (C.I. 11270),
Methyl violet FN (C.I. 42535),
Crystal violet (C.I. 42555),
Malachite green (C.I. 42000),
Victoria Blue FB (C.I. 44045),
Rhodamine B (C.I. 45170),
Acridine orange NS (C.I. 46005),
Methylene blue B (C.I. 52015) or the like is used.

As a direct dye,
Congo Red (C.I. 22120),
Direct Sky Blue 5B (C.I. 24400),
Violet BB (C.I. 27905),
Direct deep black EX (CI 30235),
Caillas Black G Conch (C.I. 35225),
Direct Fast Black G (C.I. 35255),
Phthalocyanine blue (C.I. 74180) or the like is used.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as water dispersion finely and stably dispersed in an aqueous medium in advance using a surfactant or resin. Pigment products and the like are used. I. Pigment
Blue 15: 3B [Product name: Sandye Super Blue GLL, pigment content 24%, manufactured by Sanyo Dye Co., Ltd.]
C. I. Pigment Red 146 [Product name: Sandye Super Pink FBL, pigment content 21.5%, manufactured by Sanyo Dye Co., Ltd.]
C. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.]
C. I. Pigment Red 220/166 [Product name: TC Red FG, pigment content of about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.].

As the fluorescent pigment, a fluorescent pigment in the form of fine particles of a synthetic resin in which various fluorescent dyes are formed into a solid solution in a resin matrix can be used.
In addition, white pigments such as titanium dioxide, metal powders such as aluminum, natural mica, synthetic mica, alumina, pearl pigments in which the surface of the core material is coated with a metal oxide such as titanium dioxide, cholesteric liquid crystal type glitter A functional pigment or the like can also be used.
The pigments can be used alone or in combination of two or more, and are used in the range of 1 to 25% by weight, preferably 2 to 15% by weight in the ink composition.

As the water-soluble organic solvent, conventionally used solvents that are compatible with water are used. 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 Examples include monoethyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like.
In addition, the said water-soluble organic solvent can also use 1 type (s) or 2 or more types together, and is used in 2-60 weight% in an ink composition, Preferably it is 5-35 weight%.

In addition, you may add a pH adjuster, antiseptic | preservative, or an antifungal agent, a rust preventive, a lubricant, etc. as needed.
Examples of the pH adjuster include inorganic salts such as sodium carbonate, sodium phosphate and sodium hydroxide, and water-soluble amines 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, 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine, and the like. Can be mentioned.

Specific examples of the rust inhibitor include benzotriazole and derivatives thereof, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, sodium thiosulfate, ethylenediaminetetraacetate, saponin, dialkylthiourea and the like.
Examples of the lubricant include metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic activator, phosphate ester activator, dialkyldithiocarbamate and the like.
In addition, you may add surfactant, an antifoamer, etc. as needed.

  The water-based ink composition for ballpoint pens of the present invention is used after being adjusted to a range of 5 to 20 mPa · s (20 ° C.) in measurement with a B-type viscometer using a BL adapter. When it is lower than 5 mPa · s, the handwriting tends to spread, and when it is higher than 20 mPa · s, “crying” and “bottom” at the time of writing and line breakage of the handwriting may occur.

  The water-based ink composition of the present invention is filled in a ball-point pen with a ball-point pen tip attached to the writing tip, and is used for practical use. It can be applied, but it can be applied to a ballpoint pen having a structure in which ink is stored directly in an ink storage tube fitted with a ballpoint pen tip at one end or via a relay member and an ink backflow prevention body is closely arranged on the rear end surface of the ink. Most effective.

The ballpoint pen tip is not limited in its material, structure, shape and the like, and a general-purpose one can be applied. For example, a chip having a structure in which a ball is held in a socket made of a synthetic resin, a ball receiving seat in which a plurality of locations near the tip of a metal pipe are pressed and deformed inward, and a tip portion in which the entire circumference is caulked inward Or a chip in which an ink circulation hole and a ball holding part are formed by cutting a metal bar or pipe. Further, it is possible to use the above-described chip in which the ball is urged forward by an elastic body mounted inside the chip.
The balls are made of cemented carbide, stainless steel, ruby, ceramic or the like with a diameter of about 0.2 to 2 mm.

For example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate is suitably used as the ink storage tube for storing the ink composition in terms of low ink evaporation, cost, and productivity. Further, by making the ink containing tube transparent, colored transparent, or translucent, it is possible to visually confirm the ink color, the ink remaining amount, and the like from the outside.
The ink storage tube may be a refill type in which the refill is accommodated in a shaft cylinder, or the shaft cylinder with a tip attached to the tip is used as an ink container, and ink is directly contained in the shaft cylinder. It may be filled.

  An ink backflow preventer is disposed at the rear end of the ink composition filled in the ink containing tube. As the ink backflow preventive body, a non-volatile or hardly volatile high-viscosity liquid such as polybutene, silicone oil, or mineral oil is used. Usually, a thickener such as fine-particle silica, aluminum silicate, etc. is added to the high-viscosity liquid. The viscosity is adjusted. In addition, a solid ink backflow preventive body such as a resin molded product may be used, and the high viscosity liquid-based ink backflow preventive body and the solid ink backflow preventive body may be used in combination.

  Table 1 below shows the formulation and viscosity values of Examples, and Table 2 shows the formulation and viscosity values of Comparative Examples. The ink viscosities of Examples 1 to 5 and Comparative Examples 3 to 6 were measured with a B-type rotational viscometer using a BL adapter, and the ink viscosities of Comparative Examples 1 and 2 were measured with an EM-type rotational viscometer. All ink viscosity measurements were made with the sample kept at 20 ° C.

The raw materials in the table will be described according to the note numbers.
(1) Trade name: Water Black 100-L, Orient Chemical Co., Ltd., C.I. I. 20% by weight aqueous solution of Acid Black 19 (2) Product name: Acid Blue PG, manufactured by Sumitomo Chemical Co., Ltd., C.I. I. 42655
(3) Product name: Phloxin, manufactured by Hodogaya Chemical Co., Ltd., C.I. I. 45410
(4) Product name: Sankara 634, Taiyo Kagaku Co., Ltd. (5) Product name: Prisurf AL, Daiichi Kogyo Seiyaku Co., Ltd., phosphate ester surfactant (6) Product name: Proxel XL- 2, Abisia, 1,2-benzisothiazolin-3-one (7) Product name: John Wax 26, Johnson Polymer, polyethylene wax (particle size 0.069 μm, solid content 25%)
(8) Product name: Haricoat TA-523, manufactured by Harima Kasei Co., Ltd., acrylic resin particle aqueous dispersion (solid content: 36.3%)
(9) Product name: Kelzan, manufactured by Sanki Co., Ltd. (10) Product name: Rubiscor K-30, manufactured by BASF (11) Product name: Sunphenon TA-200, manufactured by Taiyo Chemical Co., Ltd. (12) Product Name: α-G rutin P, manufactured by Toyo Seika Co., Ltd.

  For the inks of Examples 1 to 5 and Comparative Examples 1, 2, 4 and 5, a 1% by weight aqueous solution of λ-carrageenan or xanthan gum was previously prepared, and water, a water-soluble organic solvent and a colorant were added in a separate container. It was obtained by heating and dissolving, adding other additives, adding the 1% λ-carrageenan aqueous solution or the 1% xanthan gum aqueous solution, and treating with a disper at 2000 rpm for 10 minutes. Other inks were obtained by heating and dissolving water, a water-soluble organic solvent, a colorant, and a water-soluble resin, adding other additives, and treating with a propeller-type stirrer for 15 minutes.

Preparation of sample ball-point pen The inks of the examples and comparative examples were filled in a ball-point pen refill fitted with one end of a polypropylene pipe with a stainless steel chip holding a cemented carbide ball having a diameter of 0.5 mm. After arranging an ink backflow prevention body composed of 95 parts of liquid polybutene and 5 parts of hydrophobic silica so as to be in close contact with the rear end face, a ballpoint pen refill subjected to a centrifugal treatment was incorporated into a ballpoint pen barrel to obtain a sample ballpoint pen for performance test. .

[Cap-off test]
After confirming that the sample ball-point pen assembled in the above procedure can be written normally, the sample ball-point pen is left in the room horizontally in a room temperature atmosphere with the cap removed. After 30 days, letters were written on JIS P3201 writing paper A, and the state of handwriting (scratch condition) was visually observed.
[Air generation test]
The sample ball-point pen assembled in the above procedure was left in a 50 ° C. atmosphere with the chip facing upward for 60 days and then allowed to cool to room temperature, and the presence or absence of bubbles in the ink was visually confirmed.
[Discoloration test]
The ink color of the ballpoint pen left in the 50 ° C. atmosphere for 60 days was visually observed, and the color tone was compared with that of the ballpoint pen not left warm.
(Sag test)
After confirming that the sample ball-point pen assembled in the above procedure can be written normally, the sample ball-point pen was left in a 20 ° C. and 95% RH atmosphere for 20 hours in the downward direction of the chip, and the accumulation of ink at the tip of the chip was visually observed.
〔written examination〕
Using the sample ball-point pen assembled in the above procedure, a circle with a diameter of about 1 cm was continuously written on JIS P3201 writing paper A, and the presence or absence of “crying” and “bottom” was confirmed.

  The results of the test are summarized in Tables 3 and 4.

In addition, the evaluation criteria of each performance test are as follows.
[Cap-off test]
○: Can be written from the first character. △: 1-10 characters are faint. ×: More than 10 characters are fainted or cannot be written. [Air generation test]
○: No bubbles are generated Δ: One to several minute bubbles can be confirmed ×: Bubbles are expanded and the diameter is 2 mm or more [Discoloration test]
○: No discoloration observed △: Slight discoloration ×: Large degree of discoloration [sag test]
○: No ink drooping △: Slight ink droplets are observed at the tip of tip ×: Ink droplets having a diameter of 1 mm or more are observed at the tip of tip, or ink is dropped [Writing test]
○: Crying out and no bottling occurred ×: Crying out and botting confirmed

Claims (7)

  As an essential component, a colorant, water, a water-soluble polymer, a water-soluble organic solvent, and one or more selected from L-ascorbic acid, ascorbic acid derivatives, erythorbic acid and / or salts thereof are added. A water-based ink composition for a ballpoint pen, wherein the viscosity of the ink at 20 ° C. is 5 to 20 mPa · s as measured by a B-type rotational viscometer using a BL adapter.   The L-ascorbic acid, ascorbic acid derivative, erythorbic acid and / or a salt thereof is included in an amount of 0.05 to 2.0% by weight based on the total amount of the ink composition. The water-based ink composition for a ballpoint pen according to claim 1, wherein   The water-based ink composition for ballpoint pens according to claim 1 or 2, wherein the water-soluble polymer is λ-carrageenan.   The water-based ink composition for ballpoint pens according to claim 3, wherein the λ-carrageenan is contained in an amount of 0.05 to 0.5% by weight based on the total amount of the ink composition.   2. The water-based ink composition for ballpoint pens according to claim 1, wherein the colorant is a dye.   The aqueous ink composition for ballpoint pens according to any one of claims 1 to 5, wherein the ink composition contains 0.5 to 5.0% by weight of resin fine particles and / or a wax emulsion. .   The water-based ink composition for a ballpoint pen according to any one of claims 1 to 6 is directly filled into an ink containing tube in which a ballpoint pen tip is attached directly or via a connecting member, and a rear end surface of the ink composition A water-based ballpoint pen in which an ink backflow prevention body is closely arranged.