JP6837943B2 - Water-based ink composition for ballpoint pens and ballpoint pens containing them - Google Patents

Description

The present invention relates to a water-based ink composition for a ballpoint pen. Further, the present invention relates to a water-based ink composition for a ballpoint pen having excellent lubrication performance and high writing performance, and a ballpoint pen incorporating the same.

Conventionally, in a ballpoint pen containing a water-based ink having poor lubricity as compared with an oil-based ink, wear of the ball receiving seat is likely to occur due to the rotation of the ball. As a result, the ink flow path in the ballpoint pen tip is deformed, which may cause poor ink ejection or leakage. Therefore, there is a problem that the writing feeling at the time of writing is impaired and the writing is defective.
Therefore, in order to solve the above problem, an attempt to reduce wear of the ball receiving seat by adding polyoxyethylene polyoxypropylene alkyl ether phosphoric acid to the ink composition to improve the lubricity of the water-based ink is disclosed. (See Patent Document 1).
Japanese Unexamined Patent Publication No. 2014-122253

In Document 1, since polyoxyethylene polyoxypropylene alkyl ether phosphoric acid exhibits a higher lubricating effect than conventional lubricants, the number of rotations and the rotation speed of the ball with respect to the writing distance increase, resulting in severe conditions. Even when applied to an ultrafine ballpoint pen, good handwriting can be formed without causing seat wear due to writing.
However, when a pigment is used as a colorant, the pigment may aggregate depending on the amount of polyoxyethylene polyoxypropylene alkyl ether phosphoric acid added when the pigment is left in an ink state for a long period of time. In that case, the ink ejection property at the time of writing was not stable, and the handwriting may be blurred or skipped.

The present invention aims to further improve the lubricity of a water-based ink using polyoxyethylene polyoxypropylene alkyl ether phosphoric acid, which has a high lubricating effect, and eliminates the above-mentioned problems that occur when a pigment is used. is there. That is, by using the above-mentioned material, it is possible to permanently obtain an excellent writing feeling by exhibiting a higher lubricating effect for a long period of time, and it is possible to suppress the aggregation of pigments without worrying about the amount of the addition. Therefore, the present invention provides a water-based ink composition for a ballpoint pen capable of maintaining a stable ink ejection property and forming a good handwriting without blurring or line skipping for a long period of time, and a ballpoint pen incorporating the composition.

〔式（１）中、Ｒは炭素数１２〜１８であるアルキル基であり、ａ及びｂは付加モル数を示す整数である。エチレンオキサイドの付加モル数を示すａは、３〜２０の範囲、プロピレンオキサイドの付加モル数を示すｂは、１〜２０の範囲である。〕

〔式（２）中、Ｒ^１は炭素数１１〜１７のアルキル基であり、Ｒ^２は−ＣＨ_２ＣＨ(ＯＨ)ＣＨ_２ＳＯ_３ ⁻又は−Ｏ⁻であり、nは２〜４のいずれかの整数である。〕
更には、前記ボールペン用水性インキ組成物を内蔵したボールペンを要件とし、前記ボールペンが直径０．４ｍｍ以下のボールを筆記先端部に備えることを要件とする。 The water-based ink composition for a ballpoint pen of the present invention contains at least a colorant, water, polyoxyethylene polyoxypropylene alkyl ether phosphoric acid represented by the following general formula (1), and an amidamine compound represented by the following general formula (2). It is a requirement to contain it.

[In the formula (1), R is an alkyl group having 12 to 18 carbon atoms, and a and b are integers indicating the number of added moles. A indicating the number of moles of ethylene oxide added is in the range of 3 to 20, and b indicating the number of moles of propylene oxide added is in the range of 1 to 20. ]

[In the formula (2), R ¹ is an alkyl group having 11 to 17 carbon atoms, R ² is −CH ₂ CH (OH) CH ₂ SO ₃ ⁻ or −O ⁻ , and n is any of 2 to 4. Is an integer. ]
Further, a ballpoint pen containing the water-based ink composition for a ballpoint pen is required, and the ballpoint pen is required to have a ball having a diameter of 0.4 mm or less at the writing tip.

According to the present invention, it is possible to exhibit higher lubricity for a long period of time than when polyoxyethylene polyoxypropylene alkyl ether phosphoric acid is used alone, and to suppress the occurrence of pigment aggregation to maintain stable ink ejection property. Therefore, a water-based ink composition for a ballpoint pen, which can permanently obtain a better writing feeling at the time of writing and can form a good handwriting without blurring or line skipping over a long period of time, and a ballpoint pen incorporating the composition.

In the present invention, one kind alone or two or more kinds of amidamine compounds represented by the general formula (2) are contained in the water-based ink composition for a ball pen together with the polyoxyethylene polyoxypropylene alkyl ether phosphoric acid represented by the general formula (1). By adding polyoxyethylene polyoxypropylene alkyl ether phosphoric acid in combination, a higher lubricating effect can be imparted than when polyoxyethylene polyoxypropylene alkyl ether phosphoric acid is used alone, and the amount of polyoxyethylene polyoxypropylene alkyl ether phosphoric acid blended together. It is possible to reliably suppress pigment aggregation that may occur depending on the combination of types of phosphors used.
Therefore, even when a small-diameter ball of 0.4 mm or less, which has a narrow ink ejection portion and the ball rotates at an ultra-high speed during writing, is used, there is no clogging of agglomerates and wear of the ball receiving seat can be suppressed. It is possible to obtain a writing with excellent feeling and a uniform and good handwriting.

The polyoxyethylene polyoxypropylene alkyl ether phosphoric acid represented by the general formula (1) exhibits high lubricity when added to a water-based ink, and a smooth brush feel can be obtained by applying it to a ballpoint pen. Be done.
In the general formula (1), R is an alkyl group, and a substituent having 12 to 18 carbon atoms, for example, a lauryl group, a myristyl group, a palmityl group, a cetyl group, a stearyl group, an oleyl group and the like can be applied. Of these, myristyl groups, cetyl groups, and oleyl groups are particularly preferable because they are highly versatile and can exert their effects with a small amount of addition.
Further, a and b are integers indicating the number of added moles, and a indicating the number of added moles of ethylene oxide is preferably in the range of 3 to 20, more preferably in the range of 5 to 15. The b, which indicates the number of moles of propylene oxide added, is preferably in the range of 1 to 20, and more preferably in the range of 3 to 8. Those having an additional mole number within these ranges are preferably used because they have a high lubricating effect.
In the general formula (1), specifically, a is 10, b is 5, R is a combination of cetyl groups, a is 5 to 8, b is 2, R is a combination of myristyl groups, and a is 5. A combination of ~ 8, b of 2, and R of an oleyl group is particularly preferable.
When added to ink, it can also be applied as an alkali metal salt or an amine salt.

The amount of the polyoxyethylene polyoxypropylene alkyl ether phosphoric acid added can be in the range of 0.1 to 5% by mass, preferably 0.3 to 3% by mass, based on the total amount of the ink composition.
If it is less than 0.1% by mass, it is difficult to obtain the desired lubricating effect, and even if it is blended in excess of 5% by mass, the effect is not improved, and aggregation may occur depending on the type of pigment. Does not need to be added.

Since the amide amine compound represented by the general formula (2) has an amide group as a substituent, a long-chain hydrocarbon group such as ^{R 1} , and an anionic functional group such as ^{R 2.} It exists stably in an aqueous medium and exhibits a high lubricating effect over a long period of time. At that time, higher lubricity can be exhibited for a long period of time in combination with the lubricating effect of polyoxyethylene polyoxypropylene alkyl ether phosphoric acid.
Further, when a pigment is used as a colorant, high dispersion stability can be imparted, so that the ink composition can be determined without worrying about the amount of polyoxyethylene polyoxypropylene alkyl ether phosphoric acid added. it can.
As a result, an optimal water-based ink composition for a ballpoint pen, which has both high lubricity and ink ejection stability, can be obtained.

The amidoamine compound is preferably in the range of 0.05 to 5% by mass, and more preferably in the range of 0.1 to 1% by mass in the total amount of the ink composition. A high effect can be exhibited even with a small amount as in the above range.

In particular, the highest lubricating effect can be expected by adding the amidoamine compound in an amount of 0.1 to 20 times, preferably 0.3 to 10 times the amount of the polyoxyethylene polyoxypropylene alkyl ether phosphoric acid. ..

In the configuration of the present invention, the polyoxyethylene polyoxypropylene alkyl ether phosphoric acid acts preferentially on the ball of the ballpoint pen tip and the metal surface of the chip body, and the amidamine compound is further combined with the polyoxyethylene polyoxypropylene alkyl ether phosphoric acid. By interposing with the ink component, a high lubricating effect is exhibited. In particular, when a pigment is used as the colorant, the amidamine compound is interposed between the polyoxyethylene polyoxypropylene alkyl ether phosphoric acid and the pigment, so that the pigment aggregation can be efficiently suppressed in addition to the lubricating effect. It becomes a thing. At that time, if the amidoamine compound is added in an amount of more than 20 times, there is a possibility that the action of polyoxyethylene polyoxypropylene alkyl ether phosphoric acid on the metal surface is inhibited and it becomes difficult to obtain a sufficient lubricating effect. Further, if the amount is less than 0.1 times, it may be difficult to obtain the effect after a long period of time.

As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof will be illustrated below.
As the dye, acid dyes, basic dyes, direct dyes and the like can be used.
Acid dyes include ponceau (CI 16255), tartrazine (CI 19140), acid blue black 10B (CI 20470), guinea green (CI 42085), brilliant blue FCF. (CI 42090), Acid Violet 6B (CI 42640), Solve Blue (CI 42755), Naphthalene Green (CI 44025), Eosin (CI 45380), Phloxine (CI 45410), erythrosine (CI 45430), ponceau (CI 50420), acid phloxine (CI 56205) and the like are used.
As basic dyes, chrysoidin (CI 11270), methyl violet FN (CI 42535), crystal violet (CI 42555), malachite green (CI 42000), Victoria blue FB ( CI 44045), Rhodamine B (CI 45170), Acridine Orange NS (CI 46005), Methylene Blue B (CI 52015) and the like are used.
As direct dyes, Congo Red (CI 22120), Direct Sky Blue 5B (CI 24400), Violet BB (CI 27905), Direct Deep Black EX (CI 30235), Kaya Las Black G Conc (CI 35225), Direct Fast Black G (CI 35255), Phthalocyanine Blue (CI 74180) and the like are used.

The pigments include general 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 using a surfactant or the like in advance. Water-dispersed pigment products and the like are used, for example, C.I. I. Pigment Blue 15: 3B [Product name: S.I. S. Blue GLL-E, pigment content 22%, manufactured by Sanyo Dye Co., Ltd.], C.I. I. Pigment Red 22 [Product name: S.A. S. Red 1321-E, pigment content 21.5%, manufactured by Sanyo Dye Co., Ltd.], C.I. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichiseika Kogyo Co., Ltd.], C.I. I. Pigment Red 220/166 [Product name: TC Red FG, pigment content of about 35%, manufactured by Dainichiseika Kogyo Co., Ltd.] and the like can be mentioned.
As the fluorescent pigment, a synthetic resin fine particulate fluorescent pigment in which various fluorescent dyes are solid-solved in a resin matrix can be used.
In addition, pearl pigments, golden and silver metallic pigments, phosphorescent pigments, white pigments such as titanium dioxide, metal powders such as aluminum, and heat-discoloring compositions, photo-discoloring compositions, fragrances, etc. are directly or microcapsules. Examples thereof include a modified capsule pigment.

The thermochromic composition includes (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound, and (c) a reversible thermochromic composition comprising a reaction medium that determines the occurrence temperature of both of the color reactions. A sexual composition is suitable, which is encapsulated in microcapsules and applied as a reversible thermochromic microcapsule pigment.
The reversible thermochromic composition is described in Japanese Patent Publication No. 51-44706, Japanese Patent Publication No. 51-44707, Japanese Patent Publication No. 1-2398, and the like with a predetermined temperature (discoloration point) as a boundary. The color changes before and after, the color is decolorized in the temperature range above the high temperature side discoloration point, and the color is developed in the temperature range below the low temperature side discoloration point. The other state is maintained as long as the heat or cold required for the state to develop is applied, but returns to the state exhibited in the normal temperature range when the heat or cold is not applied, and the hysteresis width is A heat-decoloring type microcapsule pigment in which a reversible thermochromic composition having a relatively small property (ΔH = 1 to 7 ° C.) is encapsulated in a microcapsule can be applied.
Further, relatively large hysteresis characteristics (ΔH = 8 to 50) described in JP-A-4-17154, JP-A-7-179777, JP-A-7-33997, JP-A-8-39936 and the like. It exhibits a large hysteresis characteristic described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, and the like. That is, the shape of the curve plotting the change in coloring density due to the temperature change is significantly different between the case where the temperature is raised from the lower temperature side than the discoloration temperature range and the case where the temperature is lowered from the higher temperature side than the discoloration temperature range. A reversible thermochromic composition that changes color by following a path and has color memory in a specific temperature range when the color is developed in a low temperature range below the complete color development temperature or in a high temperature range above the complete decolorization temperature. A heat-decoloring type microcapsule pigment can also be applied.
Specifically, as the reversible thermochromic composition having color memory, the complete color development temperature can be obtained only in a freezer, a cold region, or the like, that is, −50 to 0 ° C., preferably -40 to −. 5 ° C, more preferably -30 to -10 ° C, and the complete decolorization temperature is the frictional heat of the friction body, the temperature obtained from a familiar heating body such as a hair dryer, that is, 50 to 95 ° C, preferably 50 to 90 ° C. , More preferably, it is specified in the range of 60 to 80 ° C., and the ΔH value is specified in the range of 40 to 100 ° C., so that it can effectively function to maintain the color exhibited in the normal state (daily living temperature range).

The colorant may be used alone or in admixture of two or more, and is used in the range of 1 to 30% by mass, preferably 2 to 25% by mass in the ink composition.

Further, if necessary, a conventional general-purpose water-soluble organic solvent compatible with water can be used. Specifically, 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 mono. Examples thereof include ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like.
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 mass, preferably 5 to 35% by mass.

Further, it is preferable to add a water-soluble resin in order to impart stickiness and viscosity to the paper surface. Examples of the water-soluble resin include alkyd resin, acrylic resin, styrene maleic acid copolymer, cellulose derivative, polyvinylpyrrolidone, polyvinyl alcohol, dextrin and the like. The water-soluble resin may be used alone or in combination of two or more, and is used in the range of 1 to 30% by mass in the ink composition.

In addition, general-purpose polyalkylene glycol fatty acid esters, ethylene oxide-added cationic surfactants, phosphate ester-based surfactants, thiocarbamates, dimethyldithiocarbamates, N-acylamino acids, N-acylmethyltaurine, metal soaps, etc. Can also be used in combination with the above lubricants. In particular, a phosphoric acid ester-based surfactant (phosphoric acid ester) is useful because it has a high synergistic effect when used in combination.

In addition, if necessary, inorganic salts such as sodium carbonate, sodium phosphate, sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, benzotriazole, tolyltriazole, 2,5-dimercapto- Antiseptic agents such as 1,3,4-thiazidol, saponin, coal acid, sodium salt of 1,2-benzthiazolin 3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3 , Preservatives or antifungal agents such as 5,6-tetrachloro-4- (methylsulfonyl) pyridine, urea, sorbit, mannit, sucrose, glucose, reduced starch hydrolysates, wetting agents such as sodium pyrophosphate, A defoaming agent, a fluorine-based surfactant or a nonionic surfactant that improves the permeability of the ink may be used.
In addition, ascorbic acids, erythorbic acids, α-tocopherols, catechins, synthetic polyphenols, kodiic acid, alkylhydroxylamines, oxime derivatives, α-glucosylrutin, α-lipoic acid, phosphonates, phosphinates, sulfates, sulfoxyls. Bubbles can also be chemically removed by adding acid salt, phosphite, thiosulfate, thiourea dioxide and the like.
In addition, N-vinyl-2-pyrrolidone oligomer, N-vinyl-2-piperidone oligomer, N-vinyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, ε-caprolactam, N-vinyl-ε-caprolactam By adding a thickening inhibitor such as an oligomer, the function in the infested form can be enhanced.

It is also possible to add a shear thinning agent to the ink composition.
As the shear-reducing agent, a substance soluble or dispersible in water is effective, and succinoglycan (average molecular weight) in which xanthan gum, welan gum, and the constituent monosaccharides are organic acid-modified heteropolysaccharides of glucose and galactose. Approximately 1 to 8 million), guar gum, locust bean gum and its derivatives, hydroxyethyl cellulose, alkyl ester of alginate, polymer of 100,000 to 150,000 molecular weight mainly composed of alkyl ester of methacrylic acid, glucomannan, agar and caragenin Carbohydrates with gelling ability extracted from seaweeds such as benzylidene sorbitol and benziliden xylitol or derivatives thereof, crosslinkable acrylic acid polymers, polyN-vinylcarboxylic acid amides, inorganic fine particles, nonions having an HLB value of 8 to 12. Examples of system surfactants, metal salts and amine salts of dialkyl sulfosuccinic acid can be exemplified, and further, it is stable even when N-alkyl-2-pyrrolidone and an anionic surfactant are added in combination in the ink composition. It can impart shear reduction.

The viscous characteristics of the ink composition having the above composition include so-called gel ink with high shear thinning and so-called Newtonian ink with low viscosity and low shear thinning (shear thinning) applied when using an ink retaining member or the like. Ink that does not contain an imparting agent) or the like may be used.
Due to the structure of the writing instrument, writing defects are likely to occur due to deposits on the ink retaining member or the like, so that the ink composition of the present invention having high dissolution stability is particularly useful for inks having low viscosity and low shear thinning.

The structure and shape of the ballpoint pen filled with the water-based ink composition for a ballpoint pen are not particularly limited. For example, an ink reservoir composed of a fiber bundle housed inside a barrel is impregnated with ink to impregnate the pen tip (ballpoint pen tip). ), A structure that stores ink directly inside the barrel, and a structure in which an ink flow control member consisting of a comb groove-shaped ink flow control member and a fiber bundle is interposed between the pen tip and the pen tip. Alternatively, a structure in which ink and an ink backflow prevention body (liquid plug) are housed in a shaft tube connected via a connecting member, a structure in which a ballpoint pen refill containing ink and an ink backflow prevention body is housed in an ink storage tube, etc. Can be exemplified, and either a cap type or a haunting type can be used. As the haunting type, a form in which a plurality of the refills are accommodated may be used.

As the ink backflow preventive body applied to the ballpoint pen refill, either liquid or solid can be used, and the liquid ink backflow preventive body is non-volatile such as polybutene, α-olefin oligomer, silicone oil, and refined mineral oil. Examples thereof include a sex medium, and if desired, silica, aluminum silicate, swellable mica, fatty acid amide and the like can be added to the medium. Further, as a solid ink backflow preventive body, a resin molded product can be mentioned. The liquid and solid ink backflow preventives can also be used in combination.

For the structure of the writing tip (tip) of the ballpoint pen, a conventional general-purpose mechanism is effective, and the ball is held by the ball holding portion in which the vicinity of the tip of the metal pipe is pressed and deformed inward from the outer surface. A tip made by holding a ball in a ball holding portion formed by cutting a metal material with a drill or the like, or a tip formed by cutting a metal pipe or a metal material. A ball that is urged forward by a spring body or the like can be applied.
Further, as the ball, a general-purpose ball made of cemented carbide, stainless steel, ruby, ceramic or the like can be applied, and a ball having a diameter of 0.15 mm to 2.0 mm, preferably 0.18 mm to 1.0 mm is preferable. Used for. In particular, when the ball diameter is as small as 0.5 mm or less, the number of rotations of the ball with respect to the writing distance increases, so that the ink of the present invention works more preferably. Therefore, the ink of the present invention acts very advantageously as the ball diameter becomes smaller, such as 0.4 mm, 0.38 mm, 0.35 mm, 0.3 mm, 0.28 mm, 0.25 mm, 0.18 mm, and the like. ..

The shaft cylinder, ink cartridge, and ink storage pipe (refill pipe) for accommodating the water-based ink composition are, for example, a molded body or metal made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, nylon, polycarbonate, and ABS. The work piece is preferably used in terms of low evaporation property and productivity of ink.
In particular, when the barrel, the ink cartridge, and a part or the whole of the ink storage tube are made of a transparent resin, the inside can be visually recognized, so that the remaining amount of ink and the hue can be confirmed. The transparency includes colored transparent, translucent, and colored translucent.

In addition to directly connecting the chip to the shaft cylinder, the shaft cylinder and the chip may be connected via a connecting member.
When the ink composition has a low viscosity, the ink composition contained in the barrel can be prepared by mounting an ink holding member on the front part of the barrel and directly accommodating the ink composition in the barrel, or by making the ink composition porous. Examples thereof include a method of impregnating an ink storage body such as a material or a processed fiber (such as a fiber bundle coated with an outer skin) with the ink composition and accommodating the ink.

Further, instead of directly incorporating the ink in the shaft cylinder, an ink container such as an ink cartridge or an ink storage tube may be used, or the ink storage body may be filled with ink and stored in the outer shaft. In this case, these ink accommodating bodies and ink storage bodies may have a replaceable structure.

Examples will be described below, but the present invention is not limited to these examples.
The table below shows the composition, viscosity, and shear thinning index of the water-based inks for ballpoint pens of Examples and Comparative Examples. The numerical values of the compositions in the table indicate parts by mass.
The ink viscosities of each example and comparative example are measured at 20 ° C. using a B-type rotational viscometer [manufactured by Tokyo Keiki Co., Ltd., using a BL adapter] at 60 rpm, or an E-type rotational viscometer [Toki Sangyo]. Measurement at 1 rpm using [manufactured by Co., Ltd.] was performed under any of the possible conditions.
The shear viscosity index (n) of the inks of each example and comparative example was calculated by measuring the ink viscosity at 20 ° C. using an E-type viscometer [manufactured by Tokyo Keiki Co., Ltd.].

The contents of the raw materials in the table will be explained according to the note numbers.
(1) Made by Sanyo Dye Co., Ltd., Product name: SS BLUE GLL-E
(2) Made by Hodogaya Chemical Industry Co., Ltd., Product name: Phloxine (3) Made by Fuji Pigment Co., Ltd., Product name: SP Black 8922
(4) 4.5 parts of 2- (2-chloroanilino) -6-di-n-butylaminofluorane as the component (a), and 1,1-bis (4'-hydroxyphenyl) n- as the component (b). Reversible thermochromic composition consisting of 4.5 parts of decan, 7.5 parts of 2,2-bis (4'-hydroxyphenyl) hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl capric acid as a component (c). Microcapsule pigment containing an substance [T ₁ : -20 ° C, T ₂ : -9 ° C, T ₃ : 40 ° C, T ₄ : 57 ° C, ΔH: 63 ° C, average particle size: 2.5 μm (Coulter method) , Color changes from black to colorless]
(5) POP (5) POE (10) Cetyl ether phosphoric acid (6) POP (2) POE (5) Myristyl ether phosphoric acid (7) POP (2) POE (8) Oleyl ether phosphoric acid (8) POE ( 9) Lauryl ether phosphoric acid (9) In the general formula (2), R ¹ is an alkyl group having 11 carbon atoms, R ² is −CH ₂ CH (OH) CH ₂ SO ₃ ⁻ , and n = 3 compounds (10). ^{) A compound in which R 1} in the general formula (2) is an alkyl group having 11 carbon atoms and R ² is −O ⁻ , and n = 3 (11) Stearyldimethylaminoacetate betaine, manufactured by Kao Co., Ltd., trade name: Anchitol 86B
(12) Made by ROHM & Haas Japan, Product Name: Primal ASE-60

Preparation of Inks Each component was added to water, and each ink was prepared by stirring at 20 ° C. with a disper at 400 rpm for 1 hour and filtering.

Preparation of Ink Backflow Prevention Body After adding 1.5 parts of fatty acid amide as a thickener to 98.5 parts of polybutene as a base oil, the mixture was kneaded with three rolls to obtain an ink backflow prevention body.

Preparation of Ballpoint Pen A 2.0 g of each of the ink compositions of Examples 1, 2 and 5 and Comparative Examples 1, 2 and 5 is directly contained in the barrel, and a comb groove-shaped ink flow rate adjusting member is interposed. , A stainless steel cutting tip holding a cemented carbide ball having a diameter of 0.3 mm was assembled, and then a cap was attached to prepare a sample ballpoint pen A.

Preparation of Ballpoint Pen B A stainless steel tip holding a cemented carbide ball having a diameter of 0.3 mm is fitted to one end of a polypropylene pipe with the ink compositions of Examples 3 and 4 and Comparative Examples 3, 4 and 6. 1.0 g of the ballpoint pen refill was filled, the ink backflow preventive body was arranged at the rear end of the ink, the ballpoint pen refill was incorporated into the outer shaft, and a cap was attached to prepare a sample ballpoint pen B.

The following tests were performed using the sample ballpoint pen and the ink composition.
Written test A
A sample ballpoint pen (5 each) confirmed to be writable is continuously written on JIS P3201 writing paper A with an automatic writing tester to see if the ink to be filled can be completely consumed. confirmed. The testing machine was used under the conditions of a writing load of 50 g, a writing angle of 70 °, and a writing speed of 4 m / min.
The evaluation of the test result is the number of inks that have been completely consumed (the number of printed inks).
Written test B
The writing resistance value of the sample ballpoint pen confirmed to be writable was measured at room temperature using a disk-type drawing machine (writing angle 75 °, load 100 g, writing speed 4 m / min). The obtained value is an average value (unit: g) of five writing resistance value data.
Abrasion test A sample ballpoint pen that has been confirmed to be writable is used with an automatic writing tester to continuously write 1000 m of spiral circles on JIS P3201 writing paper A, and then the amount of wear (pen) for the initial state of the ballpoint pen. The amount of ball sinking in the forward-upward state) was measured.
The testing machine was used under the conditions of a writing load of 50 g, a writing angle of 70 °, and a writing speed of 4 m / min. In addition, the measured value is an average value of five tests for each.
Ink Stability Test Each ink composition was sealed in a glass bottle and left in an environment of 50 ° C. for 30 days. Then, the state of the ink inside was visually confirmed at room temperature.
The results of each of the above tests are shown in the table below.

The evaluation of the test results is as follows.
Ink stability test ○: No abnormality.
Δ: Some agglutination is observed.
X: A large amount of agglutination is observed.

Claims (3)

A water-based ink composition for a ballpoint pen containing at least a colorant, water, a polyoxyethylene polyoxypropylene alkyl ether phosphoric acid represented by the following general formula (1), and an amidamine compound represented by the following general formula (2).

[In the formula (1), R is an alkyl group having 12 to 18 carbon atoms, and a and b are integers indicating the number of added moles. A indicating the number of moles of ethylene oxide added is in the range of 3 to 20, and b indicating the number of moles of propylene oxide added is in the range of 1 to 20. ]

[In the formula (2), R ¹ is an alkyl group having 11 to 17 carbon atoms, R ² is −CH ₂ CH (OH) CH ₂ SO ₃ ⁻ or −O ⁻ , and n is any of 2 to 4. Is an integer. ] A ballpoint pen containing the water-based ink composition for a ballpoint pen according to claim 1. The ballpoint pen according to claim 2, wherein the ballpoint pen includes a ball having a diameter of 0.4 mm or less at a writing tip.