JP3525370B2 - Method for preparing water-shrinkable water-based ballpoint pen ink, shear-thinned water-based ballpoint pen ink composition, and ballpoint pen using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a shear thinning aqueous ballpoint ink, a shear thinning aqueous ballpoint ink, and a ballpoint pen using the same.

[0002]

2. Description of the Related Art Conventional inks for ballpoint pens have a viscosity of 10 to 20,000 m.s. Pa. An oil-based ballpoint pen ink composed of an oil-based solvent system having a viscosity of 10 m.s. Pa. A low-viscosity aqueous ball-point pen ink made of an aqueous medium of about s is widely used. The oil-based ballpoint pen ink has the advantage that it is a relatively simple ballpoint pen mechanism that is filled in the pipe-shaped ink storage portion in a direct liquid state and put into practical use without interposing an ink flow rate adjusting member. High writing pressure is required because the writing feeling is heavy due to the high viscosity.
In addition, because of the mechanism that transfers the ink thin film of high viscosity ink formed on the ball surface to the writing surface, there is a blur phenomenon, so-called battering phenomenon in which ink accumulates at the tip of the writing, and in the environment where the outside temperature is high During writing, problems such as blurring of handwriting tend to occur. On the other hand, in the water-based ballpoint pen using the low-viscosity water-based ballpoint ink, there is an advantage that a dark handwriting density can be obtained with a light writing pressure, but on the other hand, an ink outflow control means or the like for appropriately flowing out the low-viscosity ink is provided. It is necessary to compose a complicated structure composed of many parts, and it is apt to cause bleeding of writing and fluffing phenomenon depending on the low viscosity of the ink.

In view of the above situation, in recent years, an ink of an aqueous medium to which thixotropy has been imparted, that is, a so-called shear thinning aqueous ball-point pen ink has been developed and put into practical use.
This type of ink has a high viscosity when it is allowed to stand without being subjected to a shear stress, and is stably held in the ballpoint pen mechanism. Only the ink in the vicinity has a low viscosity, and as a result, the ink smoothly passes through the gap between the ball and the ball accommodating portion by the capillary force, and the ink is transferred to the paper surface. Since the ink transferred to the paper surface or the like is released from the shearing force, it becomes a high viscosity state again and does not cause the handwriting bleeding phenomenon which is a defect of the conventional non-shear thinning water-based ballpoint pen.

Several proposals for the above shear thinning aqueous ballpoint pen ink have been disclosed. For example, water-dispersible gums, resins, polysaccharides, etc. (for example,
U.S. Pat. No. 4,671,691 and Japanese Patent Publication No. 64-867.
No. 3). By the way, the water-dispersible gums, resins, and thickening polysaccharides disclosed in the above proposal are denatured or deteriorated by depolymerization by microorganisms, decomposition by photochemical oxidation, and cleavage of molecular chains by strong shearing force. Therefore, it cannot be said that the shear thinning effect is stably maintained and satisfied.

Also, an organic polymer compound such as a crosslinkable acrylic resin is used as a shear thinning agent (Japanese Patent Application Laid-Open No. 5-539).
No. 7-49678, etc.) is disclosed, but even if the crosslinkable acrylic resin exhibits a certain degree of shear thinning in a high viscosity state as a property of the crosslinkable acrylic resin, in applying the aqueous ball-pen to a writing mechanism, It is not always easy to achieve that effect effectively. That is, the shear thinning effect is insufficient, and it does not always satisfy the balance between the low viscosity suitable for writing caused by the shearing force during writing and the high viscosity required for the storage state during non-writing. .

An attempt to use an inorganic compound such as inorganic fine particles as a shear thinning agent (JP-A-6-256699).
However, even if fine particles such as silicic acid anhydride fine particles show a shear thinning property by absorbing water,
The dependence of the action due to the cohesive force between the fine particles is large. Therefore, when this type of ink is applied as an ink for ballpoint pens, it is quite difficult for the three-dimensional structure of the agglomerated particles to pass through the narrow gap between the ball and the ball house in a uniform state, which causes ink shortage. Tend to be. In addition, swelling clays such as hydrophilic synthetic smectites are dispersed in fine particles as they are substantially in a dissolved state, and even if they initially give good shear thinning properties, they can cause water to lose their gel content over time. There is a tendency to cause a phenomenon of separation and discharge, that is, a "synergy" phenomenon, and there is a drawback that local separation of ink and cutting of ink columns occur in the ballpoint pen mechanism.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems with conventional ballpoint pen inks, provides a smooth writing feeling, and prepares a shear thinning water-based ballpoint pen ink that satisfies writing performance and storage performance, An object of the present invention is to provide a shear thinning aqueous ball-point pen ink and a ball-point pen using the same.

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned conventional inconveniences, the present inventors have conducted extensive studies on inks for water-based ballpoint pens, and by adding a specific surfactant to an aqueous vehicle, The inventors have found that a ballpoint pen ink having effective shear thinning properties can be obtained for a ballpoint pen, and have completed the present invention.

The present invention relates to an aqueous vehicle containing a colorant, water, and a water-soluble polar solvent, in which H 2 is added to the total amount of the vehicle.
Nonionic surfactant having an LB value selected from the range of 8 to 12 (excluding polyethylene glycol monolaurate)
1 to 30% by weight of the aqueous vehicle is mixed with stirring so that the aqueous vehicle exhibits a shear thinning property, and the viscosity is 25 to 160 m.p.m. Pa. s (value at a rotation speed of 100 rpm in an EM type rotational viscometer, 25 ° C.), and a shear thinning viscosity index is adjusted to a range of 0.1 to 0.6. The method of preparation is a requirement. Further, the nonionic surfactant (polyether
Ethylene glycol monolaurate) (excluding ethylene glycol monolaurate) is prepared so that a phase in a dispersed state in the form of fine particles of 2 μm or less and a phase in a substantially dissolved state are mixed, and further, 1 to 35 wt. %, Water-soluble polar solvent 2-35% by weight
And nonionic surfactants having an HLB value in the range of 8 to 12 (excluding polyethylene glycol monolaurate)
1 to 30% by weight, the balance being water and a conditioning additive,
Viscosity is 25 to 160 m. Pa. s (value at a rotation speed of 100 rpm in an EM type rotational viscometer, 25 ° C.), a shear thinning index of 0.1 to 0.6, and a surfactant in a finely dispersed state. A shear thinning water-based ballpoint pen ink composition in which a phase and a phase in a molecularly dissolved state are mixed is required. Furthermore, the above-mentioned nonionic surfactant has at least one or more hydroxyl groups in the molecule, and the nonionic surfactant is liquid or pasty in a temperature range from room temperature to room temperature or higher. That is, the colorant is a reversible thermochromic microcapsule pigment, in which a wall film covers a homogeneous compatible solution containing an electron-donating organic compound, an electron-accepting compound and a reaction medium for controlling the color change temperature as essential components. The particle distribution is 0.
It is a pigment that occupies 95% by volume or more in the range of 5 μm to 20 μm, and further, a reversible thermochromic microcapsule pigment that occupies 95% by volume or more in the range of 0.5 μm to 20 μm. Min), HLB value is 8 ~
1 to 30% by weight of the nonionic surfactant in the range of 12,
A water-soluble polar solvent is contained in an amount of 2 to 35% by weight, and the balance is water and an adjusting additive. Pa. s (E
A shear thinning water-based ball ink composition having a shear thinning index of 0.1 to 0.6, which is in the range of 100 rpm in M type rotary viscometer). Furthermore, the reversible thermochromic microcapsule pigment is
The requirement is that the pigment is a wall film formed by an interfacial polymerization or an interfacial polycondensation method having a depression on at least a part of the outer surface. Furthermore, in a ball-point pen which is equipped with a tip that rotatably holds a ball and is configured to draw out the ink stored in the ink storage part and to be able to write, the ink for the shear thinning aqueous ball-point pen described above in the ink storage part. A water-based ballpoint pen in which the composition is stored in a direct liquid state without interposing an ink flow rate adjusting member, and further,
The ink accommodating portion is composed of a pipe, and it is required that an ink follower is arranged at the rear end of the ink composition for a shear thinning aqueous ball-point pen in the accommodating state.

As described above, according to the present invention, when a specific amount of a specific surfactant is present in an aqueous vehicle and mixed, a shear thinning property is exhibited and a shear loss satisfying the suitability as a ballpoint pen ink and various performances is exhibited. A viscous ink is obtained. Conventionally disclosed shear thinning agent is a polymer compound, resin, gums, or inorganic fine particles as described above, whereas in the present invention, a specific low molecular weight surface active agent is used. It has been found that the agent develops an effective shear thinning function. More specifically, the present inventors have found that the nonionic surfactant has an HLB value in the range of 8 to 12, that is, a surfactant exhibiting an intermediate solubility between oil solubility and water solubility is above a predetermined concentration. It was found that, when present in an aqueous medium, the medium exhibits shear thinning properties.

The HLB value applied to the present invention is 8 to 1
The present inventors believe that the reason why the nonionic surfactant in the range of 2 exhibits shear thinning properties in an aqueous medium is as follows. A surfactant having an HLB value in the range of 8 to 12 has an intermediate property between lipophilicity and hydrophilicity, and partly dissolves in a molecular state in an aqueous medium and partly becomes fine particles. It is dispersed, and it is opaque or translucent in appearance. In such a two-phase state of a dissolved phase and a dispersed phase, fine particles composed of the dispersed phase are used as fixed points, and the surrounding dissolved phase functions as a fluid phase, resulting in a three-dimensional structure consisting of two phases when the shearing force is low. Retains its network structure and exhibits a high viscosity. On the other hand, when a strong shearing force acts, the fluid phase moves easily,
It is speculated that the three-dimensional network structure temporarily weakens, resulting in low viscosity.

The particle size of the dispersed phase is largely related to the stability of the shear thinning system, and it is necessary that the particles are dispersed in a fine state of about 2 μm or less. Generally, if it exceeds 2 μm, the dispersed phase and the dissolved phase tend to separate into two phases over time due to the difference in specific gravity between the dispersed phase and the dissolved phase, which is not preferable. Preferably, a stable system is exhibited when the dispersed phase exists in the range of 2 μm or less to several tens of nm. Aqueous media containing a surfactant having such particle properties are generally in descending order of particle size,
It has a cloudy to translucent to bluish translucent appearance.
The ink composition having such a physicochemical state has the effect of smoothly promoting ball rotation, is excellent in writing feeling, and
Wear on the ball seat is also reduced.

Further, from the viewpoint of the temperature-dependent stability of the shear thinning system, use of a liquid or pasty surfactant at room temperature can impart excellent shear thinning properties with little temperature dependency. The characteristic feature of such a surfactant is that the hydrophobic group in the hydrocarbon group in the molecule is generally a branched hydrocarbon group, an unsaturated hydrocarbon group, an aromatic hydrocarbon group, or a saturated hydrocarbon group having 12 or less carbon atoms. Because it is composed of hydrogen radicals. The expression of shear thinning in the aqueous medium in the present invention is considered to be caused by the three-dimensional network structure of the specific surfactant, but when the surfactant molecule has one or more hydroxyl groups in the molecule. Can develop a more stable and effective shear thinning property. That is, a smaller shear thinning index can be obtained. The surfactant having one or more hydroxyl groups in such a molecule is a low shear thinning index, because it can take a stronger and more stable three-dimensional network structure due to intermolecular interaction due to hydrogen bond. In other words, it is particularly effective when high thixotropy is required. Further, a surfactant having two or more hydroxyl groups in one molecule is more preferable, and examples of the hydroxyl groups include alcoholic hydroxyl groups, phosphoric acid hydroxyl groups, and phenolic hydroxyl groups.

The surfactant applied to the present invention is added in the range of 1 to 30% by weight in the water-based ballpoint pen ink, but the suitable addition amount differs depending on the individual compound, and in order to obtain the desired shear thinning viscosity. The required amount applies. 1% by weight
If the amount is less than the above, it is difficult to impart the shear thinning viscosity required for the water-based ballpoint pen ink, and if it exceeds 30% by weight, the scratches of the handwriting are apt to be generated, and further, even under a high shearing condition, the desired viscosity is not obtained. It is difficult to obtain a proper ink outflow property that corresponds to the writing speed because no decrease is obtained. The HLB value is 8 to 1
If the surfactant is in the range of 2, a plurality of surfactants may be used in combination within the above-mentioned addition amount range.

The nonionic surfactant applicable to the present invention is illustrated below, but the invention is not limited thereto. In addition, among the exemplified compounds, for example, the expression of POE (5) indicates that the compound has ethylene oxide molecules added per 5 mol on average. Therefore, when ethylene oxide is added to the 2-substituent, it means addition of 10 moles as the whole molecule.

Examples of polyglycerin fatty acid esters include the following. Hexaglyceryl monomyristate (HLB: 11.
0) Hexaglyceryl monopalmitate (HLB: 10.
0) Hexaglyceryl monostearate (HLB: 9.0) Hexaglyceryl monooleate (HLB: 9.0) Decaglyceryl monostearate (HLB: 12.0) Decaglyceryl monooleate (HLB: 12.0) Decaglyceryl monolinoleate (HLB: 12.0) Decaglyceryl monoisostearate (HLB: 12.
0) Decaglyceryl diisostearate (HLB: 9.5) Decaglyceryl dioleate (HLB: 10.0) Other than the above-exemplified compounds, polyglycerin fatty acid esters having an HLB in the range of 8 to 12 exhibit similar effects. be able to.

Examples of the ethylene oxide derivative of glycerin fatty acid ester include the following. POE (5) glyceryl monooleate (HLB: 9.
5) POE (5) glyceryl monostearate (HLB:
9.5) POE (10) glyceryl monostearate (HLB:
11.9) POE (5) glycerin cow fatty acid ester (HLB:
9.5) POE (10) Glycerin Beef Hard Fatty Acid Ester (HL
B: 11.5) Other than the exemplified compounds, glycerin fatty acid esters in the range of HLB 8 to 12 can exhibit the same effect.

Examples of polyoxyethylene sorbite fatty acid esters include the following. Tetraoleic acid POE (6) sorbit (HLB:
8.5) POE (10) sorbit tetraoleate (HLB:
9.5) POE (20) tetraoleate sorbit (HLB:
10.5) Tetraoleic acid POE (30) sorbit (HLB:
11.5) tetraoleic acid POE (35) sorbit (HLB:
12.0) Tetrastearic acid POE (30) Sorbit (HL
B: 11.0) In addition to the exemplified compounds, polyoxyethylene sorbite fatty acid esters having an HLB in the range of 8 to 12 can be applied.

Examples of polyoxyethylene sorbitan fatty acid esters include the following. POE (20) sorbitan trioleate (HLB: 1
1.0) POE (6) sorbitan monooleate (HLB: 1
0.0) POE (20) sorbitan tristearate (HLB:
10.5) POE (6) sorbitan monostearate (HLB:
9.6) In addition to the exemplified compounds, polyoxyethylene sorbitan fatty acid esters having an HLB of 8 to 12 can be applied.

[0020] The port Rie Chi glycol fatty acid esters, the following may be exemplified. PEG monostearate (10) (HLB: 11.0) PEG monooleate (10) (HLB: 11.0) PEG monooleate (6) (HLB: 8.5) In addition to the above exemplified compounds, HLB Range from 8 to 12
Rie Chi glycol fatty acid esters (polyethylene
(Excluding glycol monolaurate) is applicable.

Polyoxyethylene alkyl ethers,
Examples of the polyoxyethylene alkylphenyl ethers include the following. POE (2) lauryl ether (HLB: 9.5) POE (4) lauryl ether (HLB: 11.5) POE (2) cetyl ether (HLB: 8.0) POE (5.5) lauryl ether (HLB: 10.
5) POE (7) lauryl ether (HLB: 10.5) POE (2) stearyl ether (HLB: 8.0) POE (4) stearyl ether (HLB: 9.0) POE (7) oleyl ether (HLB: 10.5) POE (10) behenyl ether (HLB: 10.0) POE (5) nonyl phenyl ether (HLB: 8.
0) POE (10) octyl phenyl ether (HLB: 1
1.5)

The following compounds can be exemplified as polyoxyethylene polyoxypropylene alkyl ethers. POE (1), POP (4) cetyl ether (HLB:
9.5) POE (10), POP (4) cetyl ether (HL
B: 10.5) POE (1), POP (8) cetyl ether (HLB:
9.5) POE (20), POP (8) cetyl ether (HL
B: 12.5) POE (12), POP (6) tetradecyl ether (HLB: 8.5) POE (12), POP (6) tetradecyl ether (HLB: 11.5) POE (12), POP (6) Tetradecyl ether (HLB: 12.0)

Examples of the fatty acid monoethanolamide include the following compounds. Lauric acid monoethanolamide, myristic acid monoethanolamide, palmitic acid monoethanolamide, stearic acid monoethanolamide, behenic acid monoethanolamide, isostearic acid monoethanolamide, oleic acid monoethanolamide, ricinoleic acid monoethanolamide, linoleic acid Examples include monoethanolamide.

Examples of the fatty acid diethanolamides include the following compounds. Lauric acid diethanolamide, myristic acid diethanolamide, palmitic acid diethanolamide, stearic acid diethanolamide,
Behenic acid diethanolamide, isostearic acid diethanolamide, oleic acid diethanolamide, ricinoleic acid diethanolamide, linoleic acid diethanolamide, etc. are 1: 1 type and 1: 2 type, respectively, and one or more of these may be used. The value of HLB is 8 by mixing
It can be used by adjusting the range from 1 to 12.

Examples of polyoxyethylene fatty acid amides include the following. Here, the number in parentheses represents the average number of added moles in the ethylene oxide chain.
POE (2-5) lauric acid amide, POE (2-6)
Myristic acid amide, POE (2-7) palmitic acid amide, POE (2-8) stearic acid amide, POE
(2 to 10) oleic acid amide, POE (2 to 7) isostearic acid amide, POE (2 to 7) linoleic acid amide, POE (2 to 7) ricinoleic acid amide, POE
(2 to 10) behenic acid amide and the like can be exemplified, and among these, the HLB value by mixing one kind or two or more kinds is 8
Can be used as a mixture of 1 to 12. Preferably, the liquid or paste-like polyoxyethylene fatty acid amide at room temperature exhibits shear thinning excellent in temperature stability.

Examples of polyoxyethylene alkylamines include the following. POE (2-5) amine laurate, POE (2-6) amine myristate,
POE (2-7) amine palmitate, POE (2-
8) amine stearate, POE (2-10) amine oleate, POE (2-7) amine isostearate,
POE (2 to 7) amine linoleate, POE (2 to 7)
7) Amine ricinoleate, amine POE (2-10) behenate, and the like can be exemplified, and from these, one or a mixture of two or more can be used as a mixture having an HLB value of 8 to 12. Preferably, the liquid or pasty polyoxyethylene fatty acid amine at room temperature exhibits a shear thinning property excellent in temperature stability.

The saccharide esters include the following. The constituent carboxylic acids of sucrose ester are lauric acid, myristic acid, stearic acid behenic acid, isostearic acid, oleic acid, linolenic acid, ricinoleic acid,
A sucrose ester simple substance or a mixture of HLB in the range of 8 to 12 is selected from one or more compounds selected from mono- and diesters and triesters such as sucrose consisting of beef tallow fatty acid and the like. The sucrose ester compound is generally available as DK ester (sucrose ester manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and for example, DK ester F-110 (HLB about 11), F-90 (HLB about 9), F. -70 (HLB about 8) and the like can suitably exhibit shear thinning properties.

As the phosphoric acid esters, a single compound or a mixture of monoesters, diesters and triesters of the following exemplified compounds can be used. POE (1-2) n-decyl ether phosphate ester POE (1-2) n-undecyl ether phosphate ester POE (1-3) n-dodecyl ether phosphate ester POE (1-3) n-isotri Decyl ether phosphate ester POE (1-3) n-myristyl ether phosphate ester POE (1-4) n-cetyl ether phosphate ester POE (1-4) n-stearyl ether phosphate ester POE (1-6) n-Behenyl ether phosphate ester POE (1-4) n-isostearyl ether phosphate ester POE (1-4) n-nonyl phenyl ether phosphate ester POE (1-4) n-oleyl ether phosphate ester n- Decyl phosphate ester, n-dodecyl phosphate ester, n-undecyl phosphate ester, isotolide Berlin esters, Mirisuchirurin acid ester, cetyl esters, stearyl esters, isostearyl phosphate esters, Behenirurin acid esters, oleyl esters, such as nonylphenyl phosphoric acid ester can be exemplified. HLB is 8 even in the compounds other than the exemplified compounds.
Phosphoric acid esters in the range of to 12 can exert similar effects. In the case of the above-mentioned phosphoric acid esters, the pH can be adjusted by partially neutralizing with an inorganic or organic base component, if desired.

Compound groups other than the above include polyoxyethylene alkylphenyl formaldehyde condensates,
Among nonionic surfactants such as polyoxyethylene lanolins, polyoxyethylene lanolin alcohols, polyoxyethylene sorbit beeswax, polyoxyethylene castor oils, polyoxyethylene castor hydrogenated oils, sorbitan fatty acid esters, etc. of HLB A single compound in the range 8-12 or two or more compounds can be used as a mixture.

As the colorant used in the ink composition of 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. Among the dyes, C.I. I. Acid dyes such as Blue 93,
Direct dyes such as Direct Black 154 and basic dyes such as rhodamine and methyl violet can be used.
The pigments include inorganic pigments such as carbon black and ultramarine blue, organic pigments such as copper phthalocyanine blue and benzidine yellow, and water-dispersed pigment products that have already been finely and stably dispersed in an aqueous medium using a surfactant. Can be used easily. For example, C.I. I. Pigment 15: 3B
[Product name: S. S. Blue GLL, pigment content 24%, Sanyo Dye Co., Ltd.], C.I. I. Pigment Re
d 146 [Product name: S. S. Pink FBL, pigment content 21.5%, Sanyo Dye Co., Ltd.], C.I. I. Pigm
ent Yellow 81 [Product Name: TC Yellow
wFG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.],
C. I. PigmentRed 220/166 [Product Name:
TC Red FG, pigment content about 35%, manufactured by Dainichiseika Kogyo Co., Ltd.] and the like. As fluorescent pigments, synthetic resin fine particle fluorescent pigments in which various fluorescent dyes are solid-solved in a resin matrix can be used, as well as pearl pigments, gold / silver metallic pigments, luminous pigments, and titanium oxide used for correction pens. Examples thereof include white pigments such as, and fragrances or fragrance capsule pigments.

The above colorants can be used alone or in combination of two or more, and the amount of these used is from 1 to 35% by weight.
However, the addition amount can be appropriately set according to the colorability of the pigment itself and the purpose of use. Further, as an application example of useful pigments, reversible thermochromic microcapsule pigments can be used. Here, the water-based ballpoint pen composition of the present invention using the reversible thermochromic microcapsule pigment as a colorant will be described.

The reversible thermochromic microcapsule pigment is composed of a thermochromic material composed of an electron-donating color-developing organic compound, an electron-accepting compound, and a homogeneous compatible solution of a color-changing temperature adjusting agent. Conventionally known types that reversibly develop / decolor at a predetermined temperature, for example, Japanese Patent Publication Nos. 51-44706, 51-44708, 52-7764, and 51-35414. No. 1-29398, or discoloration with a large hysteresis characteristic, in the temperature range between the low-temperature side discoloration point and the high-temperature side discoloration point, both the colored state and the colorless state or both the colored (A) and colored (B) phases. Japanese-Fairness 4-
It is obtained by encapsulating the thermochromic material disclosed in JP-A No. 17154, JP-A No. 7-33997, and JP-A No. 7-179777 into fine particles or forming a resin matrix by a known microencapsulation method. Anything can be applied.

The reversible thermochromic microcapsule pigment is present in a dispersed state in an aqueous medium used in the present invention, and the thermochromic microcapsule pigment is an electron-donating organic compound or an electron-accepting compound. And a homogenous solution containing a reaction medium for adjusting the discoloration temperature as an essential component, which is coated with a wall film, and has a particle distribution of 0.5% to 20 μm in a range of 95%
(Volume%) or more, more preferably, the reversible thermochromic microcapsule pigment is a pigment composed of a wall film formed by an interfacial polymerization or interfacial polycondensation method having a depression on at least a part of its outer surface. And more preferably 5 to 3 reversible thermochromic microcapsule pigments having a particle distribution of 0.5 vol.
5% by weight (solid content) is blended and the viscosity is 30-16
0 m. Pa. It is preferable that it is in the range of s (value at a rotation speed of 100 rpm in an EM type rotational viscometer at 25 ° C.), and the shear thinning index of the ink is in the range of 0.1 to 0.6.

Here, as described above, the microcapsule pigment having depressions on at least a part of its outer surface (see FIGS. 2 to 5) is an ink having the same viscosity as compared with a spherical body having a perfect circular cross section (see FIG. 1). However, external force (pressure generated during writing, etc.)
Even if it receives a stress, the stress is due to its own elastic deformation,
The pressure is relieved and the capsule itself is not destroyed and properly flows out from the ballpoint pen tip to give the desired handwriting performance.

Although the ink composition of the present invention uses water as a main solvent, as a water-soluble polar solvent, all of the conventional solvents which are compatible with water are also effective, and glycerin, triethanolamine, diethanolamine, monoethanolamine. , Ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, N-methyl-2
-Pyrrolidone etc. can be used. The amount used is preferably 2 to 35% by weight in the composition.

As the adjusting additive, as the PH adjusting agent,
Inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, and organic basic compounds such as water-soluble amine compounds can be applied. Benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin and the like can be used as the rust preventive. Examples of the antiseptic or antifungal agent include carboxylic acid, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,
3,5,6-tetrachloro-4- (methylsulfonyl) pyridine and the like can be mentioned. As a wetting agent, urea,
Nonionic surfactants, sorbit, mannitol, sucrose, glucose, reduced starch hydrolysates, sodium pyrophosphate, etc. can be used, as well as fluorochemical surfactants and nonionic surfactants to improve ink penetration. Activators may be used. The adjusting additive is a so-called conventional additive, and can be appropriately selected from known compounds as necessary.

Further, a polymer having substantially no shear thinning property can be added for the purpose of providing a binder or water resistance. Examples of such polymers include linear polymers such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid resins, and styrene-maleic acid resins.
Further, known resins having shear thinning properties, gums, thickening polysaccharides, inorganic particles and the like can be used together. The shear thinning property of the ink composition of the present invention has a property that the viscosity is remarkably high and does not easily flow when in a static state or a low stress, and a rheological property showing low viscosity and good flowability when the stress increases. To tell. It means a common liquid property also called thixotropic or pseudoplasticity.

In the ink composition of the present invention, under high shearing stress during writing, the three-dimensional structure is temporarily destroyed and the viscosity of the ink decreases, and the ink near the ball becomes a low viscosity ink suitable for writing. It moves through 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 ink, including the vicinity of the ball, becomes high, so that ink leakage can be prevented, and ink separation and backflow can be prevented. Also, the physical properties of the ink can be kept stable over time.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION The ink of the present invention is a so-called direct liquid, which is directly filled in an ink containing portion 4 of a ballpoint pen having a conventionally known ballpoint pen tip as a writing tip without interposing an ink flow rate adjusting member. It can be put to practical use in the state (see FIG. 11). A configuration in which the ink follower 7 is arranged in contact with the rear end portion of the ink 6 stored in the ink storage portion 4 is generally used. It is also possible to use a structure in which ink is accommodated in a flexible barrel and the barrel is appropriately pressed and deformed to adjust the ink output, without using an ink follower. Regarding the ball-point pen tip structure, the difference S between the inner diameter A of the ball accommodating portion 3 and the outer diameter B of the ball 2 and the space C that can be moved in the axial direction of the ball 2 are appropriately determined depending on the type of ink, the purpose, etc. It can be set in the range, and a conventional chip mechanism, for example, a chip in which a ball receiving seat and an ink lead-out portion are integrally formed by pressing and deforming the tip end portion of a metal pipe inward from the outer surface (FIG. 6, FIG. 7) or a chip (FIGS. 8 and 9) having a ball receiving seat 33, a central hole 31, and a radial lead-out groove 32 formed inside by cutting a metal material with a drill or the like, or the ball is moved forward by a spring body. A mechanism (FIG. 10) for urging the ball to move and a writing or applicator in which the ball is rotatable are effective. Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples. Further, the shear thinning viscosity index (n) in the examples is an empirical formula (T = Kj ⁿ : K and n are obtained by rheological measurement based on viscosity diameters such as shear stress value (T) and shear rate (j) value. The calculated n value is shown. The compounding numbers in the examples indicate parts by weight.

Example 1                                                               (Part by weight)   Black pigment [SS BLACK C, pigment content 28%, Sanyo Dye Co., Ltd.] 19.4   Glycerin 3.0   Silicone defoamer 0.1   Preservative [Proxel XL-2, manufactured by Zeneca] 0.1   Decaglyceryl diisostearate 12.1     [NIKKOL DEC2-IS, manufactured by Nikko Chemicals Co., Ltd.]   Water 65.3 ───────────────────────────────────                                                             100.0

Preparation of Ink Of the predetermined amount, first, decaglyceryl isodistearate is uniformly dispersed in water by heating. After cooling to room temperature, a black pigment was added while stirring, glycerin, an antifoaming agent and an antiseptic agent were added, and suction filtration was performed with a G3 glass filter to remove coarse substances, to obtain an ink composition of the present invention. The obtained ink had a shear thinning index (n): 0.41, a viscosity (100 rpm): 71 m.p. Pa. It was s (25 degreeC).

Fabrication of ball-point pen A cutting-type ball-point pen tip using a ball having a diameter of 0.5 mm and having a difference S between inner diameter A and outer diameter B of the ball receiving portion S = 20 μm and a space C = 20 μm movable in the axial direction. Using. 1.2 g of a polypropylene pipe having an inner diameter of 3.3 mm was filled with the ink composition and connected to the ballpoint pen tip through a resin holder. Then, from the tail of the polypropylene pipe, fill a polybutene-based viscoelastic ink follower (liquid stopper),
After deaeration by centrifugal treatment, a ball-point pen was obtained by mounting an exterior barrel, a base, a tail plug, and a cap. When I wrote continuously on the report paper using the ballpoint pen, a clear black handwriting was obtained from the writing,
Good writing performance was exhibited without line cracks, line breaks, and ink bloating.

Example 2 (parts by weight) Orange fluorescent pigment dispersion 15.0 [Lumicol 2104, manufactured by Nippon Fluorescent Science Co., Ltd.] Glycerin 5.0 Urea 1.0 Silicone-modified antifoaming agent 0.1 Colic acid 0.1 Benzotriazole 0.5 Tetraoleic acid POE sorbit (30EO) 12.1 [NIKKOL GO-430N, manufactured by Nikko Chemicals Co., Ltd.] Water 66.2 ─────────────────── ─────────────────── 100.0 Ink was prepared in accordance with Example 1 above. The same applies to the following examples. The resulting ink had a shear thinning index (n) of 0.20 and a viscosity (100 rpm) of 102 m.
Pa. It was s (25 degreeC).

Fabrication of ballpoint pen Ball diameter 0.7 mm, axially movable space C
A ballpoint pen was prepared in the same manner as in Example 1 except that the thickness was 50 μm. When writing continuously on a report paper using this ballpoint pen, clear blue handwriting was obtained from the initial writing, and good writing performance was exhibited without smearing, line cracking, line breakage, and ink bloating.

Example 3 (parts by weight) Blue material dispersion 15.6 [SS BLUE HB, pigment content 25%, manufactured by Sanyo Dye Co., Ltd.] Glycerin 2.6 Urea 1.0 Silicone-modified antifoaming agent 0.2 Coal acid 0.1 Benzotriazole 0.5 Hexaglyceryl monooleate 11.7 [NIKKOL HEX 1-O, manufactured by Nikko Chemicals Co., Ltd.] Water 68.3 ──────────────── ───────────────────── 100.0 The obtained ink had a shear thinning index (n): 0.34, a viscosity (100 rpm): 61 m.p. Pa. It was s (25 degreeC).

Production of ball-point pen A stainless-steel ball having a diameter of 0.5 mm was mounted, and the difference between the pipe inner diameter A and the ball outer diameter B was set to S = 25 μm and the axially movable space C was set to 20 μm. A ballpoint pen was assembled according to Example 1 by using a press-deformation type ballpoint pen tip (FIGS. 6 to 7) and other members. When writing continuously on a report paper using the above ballpoint pen, clear black handwriting was obtained from the start of writing, and good writing performance was exhibited without smearing, line breakage, line breakage, and ink bloating.

Example 4 (parts by weight) Red pigment dispersion 26.1 [SS RED RR, pigment content 25%, Sanyo Dye Co., Ltd.] Glycerin 3.3 Urea 3.3 Silicone-modified defoamer [Dehydrane 1620 ] 0.1 Preservative [Proxel XL-2, manufactured by Zeneca] 0.2 Oxyethylene (2) lauric acid amide 8.4 [LAD [2], manufactured by Meisei Chemical Industry Co., Ltd.] Water 58.6 --- ────────────────────────────────── 100.0 The obtained ink has a shear thinning index (n). : 0.24, viscosity (100 rpm): 65 m.p.m. Pa. It was s (25 degreeC).

Preparation of Ballpoint Pen A ballpoint pen was constructed by filling ink in the same manner as in Example 1 and continuous writing was performed. As a result, a dark red handwriting was obtained from the writing, and blurring, line breakage, line breakage, and ink It showed good writing performance without the fluff phenomenon.

Example 5 (parts by weight) Red pigment dispersion 16.6 [SS RED RR, pigment content 25%, Sanyo Dye Co., Ltd.] Ethylene glycol 7.2 Silicone-modified defoamer 0.1 Preservative [ Proxel XL-2, manufactured by Zeneca] 0.1 Polyoxy (5) oleylamine 11.8 [TAMNO-5, manufactured by Nikko Chemicals Co., Ltd.] Water 64.2 ─────────────── ───────────────────── 100.0 The obtained ink had a shear thinning index (n) of 0.48 and a viscosity (100 rpm) of 29 m.p. Pa. It was s (25 degreeC).

Preparation of Ballpoint Pen A ballpoint pen was constructed by filling ink in the same manner as in Example 1, and when continuous writing was performed, a dark red handwriting was obtained from writing, and blurring, line cracking, line breakage, and ink It showed good writing performance without the fluff phenomenon.

Example 6 (parts by weight) Black dye aqueous solution [C. I. Direct black 20% aqueous solution] 19.7 [SS Green LXB, pigment content 30%, Sanyo Dye Co., Ltd.] 5% sucrose ester aqueous solution [DK Ester F-90] 56.2 Glycerin 11.2 Urea 2.8 5% aqueous sodium borate solution 8.4 Silicone-modified defoaming agent 0.1 Preservative [Proxel XL-2, manufactured by Zeneca] 0.2 Permeation enhancer [SN-WET 366, manufactured by San Nopco Ltd.] 1.4 ─ ─────────────────────────────────── 100.0 The obtained ink has a shear thinning index (n ): 0.45, viscosity (100 rpm): 33 m. Pa. It was s (25 degreeC).

Preparation of Ballpoint Pen A ballpoint pen was constructed by filling ink in the same manner as in Example 1, and when continuous writing was performed, a dark pink handwriting was obtained from the writing, and blurring, line cracking, line breakage, and ink It showed good writing performance without the fluff phenomenon.

Example 7 A method for preparing a thermochromic microcapsule pigment used in this example will be described. A thermochromic composition comprising 2 parts of 6- (ethylisobutylamino) benzofluorane, 6 parts of bisphenol A, 30 parts of cetyl alcohol, and 20 parts of stearyl caprate and 1 part of tinuvin 326 as a light resistance-imparting agent, and then as a film material. Epoxy equivalent 190 obtained by reaction of bisphenol A with epichlorohydrin
15 parts of the epoxy resin of Example 1 were uniformly heated and melted, and emulsified with 100 parts of the aqueous protective colloid medium preheated to 70 ° C. with a homomixer so that the average particle size was 2.5 μm. Then, 5 parts of an aliphatic polyamine curing agent was added, and stirring was continued at 90 ° C. for 5 hours to obtain a microcapsule dispersion liquid by an interfacial polymerization method. Then, centrifugation treatment was performed to concentrate the microcapsules to obtain 100 parts of a slurry.

The water content of the capsule slurry was measured and found to be 38%. Then, in order to measure the particle size distribution, the particle size characteristics were measured by a centrifugal sedimentation type automatic particle size distribution measuring device (CAPA-300 manufactured by Horiba, Ltd.).
When the particle diameter is D, the relationship between the particle diameter and the occupied volume% was as follows. The cumulative total of 0.5 μm ≦ D ≦ 20 μm was 97%, and the average particle size was 2.7 μm. When the obtained microcapsules were observed with a microscope, it was confirmed that they were hemispherical flat capsules having recesses (see FIGS. 2 to 5). Further, the flatness increased as the particle size increased.

The thermochromic microcapsule pigment thus obtained exhibited a magenta color at a temperature of about 27 ° C. or lower and a colorless color at a temperature of 32 ° C. or higher, and there was a transitional period between the two temperatures.
An aqueous ballpoint pen ink was prepared by the following formulation using the microcapsules as a colorant. (Parts by weight) Thermochromic microcapsule pigment (solid content 65%) 24.8 Glycerin 4.2 Urea 3.7 Silicone-modified defoaming agent 0.1 Preservative [Proxel XL-2, manufactured by Zeneca] 0.1 Hexaglyceryl monooleate 12.4 [NIKKOL HEX 1-O, manufactured by Nikko Chemicals Co., Ltd.] Water 54.6 ───────────────────────── ───────────── 100.0 The obtained ink had a shear thinning index (n) of 0.35 and a viscosity (100 rpm) of 96 m. Pa. It was s (25 degreeC).

Production of ball-point pen A ball-point pen tip of the deformation type of a pipe is applied,
A stainless steel ball with a diameter of 0.7 mm is used, and the ball receiving portion has a difference S between the pipe inner diameter A and the ball outer diameter B = 25 μ.
m, the space C movable in the axial direction was set to 46 μm, and the other members were applied according to Example 1 to assemble the ballpoint pen. After continuous writing on the report paper, a clear black handwriting was obtained from the start of writing, and good writing performance was exhibited without scratches, line breaks, line breaks, and ink bloating. Handwriting is magenta at 27 ° C or below, 32 ° C
As described above, it was confirmed that the material was colorless and that there was no deterioration in the performance of the handwriting with time.

Example 8 The thermochromic composition of Example 7 was treated with 2- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide 2 .5
Parts, 2,2-bis (4-hydroxyphenyl) hexafluoropropane 5 parts, and isoamyl stearate 50 parts, except that the thermochromic microcapsule pigment was obtained in the same manner as in Example 7. The water content of the capsule slurry was 32%, and the thermochromic microcapsule pigment obtained had a blue color at 16 ° C or lower and a colorless color at 18 ° C or higher. Using the obtained microcapsules as a coloring agent, an aqueous ballpoint pen ink was prepared by the following formulation. (Parts by weight) Thermochromic microcapsule pigment (solid content 68%) 24.9 Hexaglyceryl monostearate 3.1 [HEX-1-S, Nikko Chemicals Ltd.] Glycerin 5.0 Urea 2.5 Silicone Modified defoaming agent 0.1 Preservative [Proxel XL-2, manufactured by Zeneca] 0.1 Water 64.3 ───────────────────────── ──────────── 100.0 The obtained ink had a shear thinning index (n) of 0.29 and a viscosity (100 rpm) of 96 m. Pa. It was s (25 degreeC).

Preparation of Ballpoint Pen A ballpoint pen was assembled according to Example 7. When writing continuously on a report paper using the ballpoint pen, a clear blue handwriting was obtained from the writing, scrapes, line breaks,
Good writing performance was exhibited without line breaks and ink bloating. The handwriting was blue at 16 ° C. or lower and colorless at 18 ° C. or higher, and it was confirmed that the performance of the handwriting did not deteriorate with time.

Comparative Example 1 An ink composition was prepared by substituting all the tetraoleic acid POE sorbit (30EO) in Example 2 with water. The ink had a low viscosity and did not have shear thinning properties, and the ink blobbing phenomenon remarkably occurred immediately after assembling into a ballpoint pen. When the ink was written, the ink bleeding was severe and unsuitable for writing. The obtained ink has a shear thinning index (n): 1.0.
0, viscosity (100 rpm): 2 m. Pa. s (25
℃).

Comparative Example 2 All the decaglyceryl diisostearate in Example 1 was POE sorbitan monooleate (20EO) (H
LB: 15.0) [NIKKOLTO-10, manufactured by Nikko Chemical Co., Ltd.] to obtain an ink composition. The ink had a low viscosity and did not have shear thinning property, and the ink blobbing phenomenon remarkably occurred immediately after assembling into a ballpoint pen. When writing, the ink bloating was severe and unsuitable for writing. The obtained ink had a shear thinning index (n) of 1.00 and a viscosity (100 rpm) of 12 m. Pa. It was s (25 degreeC).

The results of the writing tests of the ball-point pens filled with the inks of Examples 1 to 8 and Comparative Examples 1 and 2 and the evaluation of the stability over time are shown in the table.

[Table 1] The test items in the table will be described below. Handwriting density and stability Intermittent writing lines, blurring, and uniformity of density were observed and comprehensively evaluated. Ink Leakage Test The pen tip of a ball-point pen filled with ink was held in the downward state in the air, and the state of the ink leaked from the pen tip after 1 hour was visually observed and evaluated. During writing, press the pointed ballpoint pen strongly against the paper surface and let it stand for 1 minute, then visually observe the size of the ink spread on the paper surface and the degree of local ink flapping during actual continuous writing (loop writing). And evaluated. Line breaking A state in which the writing line appears double when the periphery of the writing line is dark and the central part is thin. The handwriting was observed with a magnifying glass and the degree was evaluated.

[0062]

INDUSTRIAL APPLICABILITY According to the present invention, a specific amount of a specific nonionic surfactant is blended to form a specific aqueous liquid state, thereby exhibiting a desired shear thinning property, and suitable suitability as a ballpoint pen ink. It has properties such as filling, line cracking of the handwriting, blurring, and battering, and viscosity characteristics that are stable over time, and satisfies practical performance as an aqueous ballpoint pen ink containing various colorants. Further, various kinds of pigments and dyes can be applied as the colorant, and a ballpoint pen exhibiting various color tones can be provided. Furthermore, in the system to which the thermochromic microcapsule pigment is applied as the colorant, a convenient ballpoint pen that gives thermochromic handwriting can be provided, and new applications can be developed. The application and the effect thereof are illustrated below. (1) Magical applications such as postcards, Christmas cards, greeting cards, etc. that can form images such as secret letters and patterns that discolor at temperatures lower than room temperature, and make the image appear by cooling, or colored (A) It is possible to form an image exhibiting color (B) tautomerism, and to discolor at body temperature or hand temperature. (2) In a system in which a thermochromic pigment that changes color only when it is cold, such as 10 ° C., or a thermochromic pigment having hysteresis characteristics in a wide temperature range is applied as a secret pen,
It becomes possible to make unreadable records at room temperature, and is used for memos that require confidentiality. (3) In a system to which a color-memory thermochromic pigment having a hysteresis characteristic is applied, write necessary answers and supplementary notes and heat them for learning purposes such as question collections, tests, drills, blank maps, and English translations. This has the advantage that the handwriting can be erased and the problem can be tackled again without a completely reset answer or note. Even in a system that gives a handwriting of 10 ° C discoloration, the above-mentioned use can be satisfied, and a set product can be constructed by combining with a discoloring tool using cold water, ice chips, or the like as a refrigerant. (4) Write a message on the side of a container such as a paper cup with a thermochromic ballpoint pen that discolors at 10 ° C, and pour a cold drink, the message will appear, and it is suitable for party products and fancy products, together with lightness It is effective as a product. (5) The present invention can be applied to temperature indicating purposes that serve as a thermometer. Providing a plurality of thermochromic ballpoint pen sets with different discoloration temperatures, it can play the role of temperature detection by forming various images, is not limited to toys, stationery applications, various industrial fields, for example, It can be applied to convenient operations such as temperature control of reaction tank, temperature control in processing process, indicator for proper temperature control of low temperature food, and overheat prevention display due to short circuit of electrical cord outlet. (6) In the field of clothing, by drawing illustrations and designs on casual wear such as T-shirts with a thermochromic ballpoint pen that discolors at 30 ° C, color changes that take advantage of the temperature difference between the outdoors and indoors in the summer It can also be applied to gloves, shoes, hats, ski wear, swimwear, etc., where users can design their own T-shirts. (7) In the field of sewing processing, a guide line is formed by using a thermochromic ballpoint pen having a memory property to form a handwriting in a colored state, and heating it with a iron or the like to a temperature exceeding the high temperature side trigger after sewing. Can be erased. As an example of a memory-based discoloration function for such an application, a low temperature side trigger -10 ° C and a high temperature side trigger 4
A system to which a thermochromic pigment having a temperature of 0 ° C is applied is effective. (8) In the field of anti-counterfeiting, it is possible to distinguish a genuine product from a forged product by cooling or heating. For example, it is effective for preventing forgery by handwriting such as tickets, cash vouchers, and coupon tickets in individual shops and small lot scales. If desired, the discoloration temperature, the type of discoloration, and the color can be marked by date and period, which is particularly useful for applications requiring short-term identification. (9) In the field of toys, for example, you can write your own design on the part with stuffed toys and use it to warm the body temperature to enjoy its discoloration, lips, nails, and around the eyes of a doll. Colored with a thermochromic ballpoint pen that has a memory effect of shadow color, you can repeatedly play two states of "makeup state" and "non-makeup state" with a color changing tool using hot water and ice water, ball diameter 1 mm ~ Two
A ball-point pen for thick writing of about mm can exert its effect more effectively. (10) As a drawing pen for designers, a rough color sketch is drawn in the color-developed state using a memory-type thermochromic temperature pen, and then the final design or picture is drawn up with general drawing materials. After that, it is effective for the purpose of heating and erasing the rough sketch line drawing. (11) On a part of each piece of the jigsaw puzzle completed as a picture, write a number or symbol with a thermochromic ballpoint pen whose room temperature is below room temperature so that the position when engaged can be confirmed in advance. When the combination becomes difficult, the position can be confirmed by partially cooling and expressing handwriting. (12) You can enjoy the two picture states by drawing graffiti on face photographs, paintings, etc. with a memory thermochromic ballpoint pen with low-temperature discoloration temperature of 10 ° C and high-temperature discoloration temperature of 35 ° C, and heating and cooling. In addition, the aspect of change can be further diversified by combining it with a non-discoloring general ballpoint pen.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of the outer shape of an example of a microcapsule pigment. (A) shows an external appearance and (B) shows a cross-sectional view.

FIG. 2 is a schematic explanatory view of the outer shape of another example of the microcapsule pigment. (A) shows an external appearance and (B) shows a cross-sectional view.

FIG. 3 is a schematic explanatory view of the outer shape of another example of the microcapsule pigment. (A) shows an external appearance and (B) shows a cross-sectional view.

FIG. 4 is a schematic explanatory view of the outer shape of another example of the microcapsule pigment. (A) shows an external appearance and (B) shows a cross-sectional view.

FIG. 5 is a schematic explanatory view of the outer shape of another example of the microcapsule pigment. (A) shows an external appearance and (B) shows a cross-sectional view.

FIG. 6 is a vertical cross-sectional explanatory view of an embodiment of the tip portion of the ballpoint pen of the present invention.

7 is a cross-sectional view taken along line XX of FIG.

FIG. 8 is a vertical cross-sectional explanatory view of an embodiment of the tip portion of the ballpoint pen of the present invention.

9 is a cross-sectional view taken along line XX of FIG.

FIG. 10 is an explanatory longitudinal sectional view of another example of the tip portion of the ballpoint pen of the present invention.

FIG. 11 is a vertical cross-sectional explanatory view of an embodiment of the ball-point pen of the present invention.

[Explanation of symbols]

1 ballpoint pen Two balls 3 ball storage 31 central hole 32 Outlet hole 33 ball catch 4 Ink storage 5 microcapsule pigment 51 membrane wall 52 depression 53 Thermochromic composition 6 Shear thinning ballpoint ink 7 Ink follower

Claims (11)

(57) [Claims] 1. An aqueous vehicle containing a colorant, water, and a water-soluble polar solvent, and a nonionic surfactant ( porosity) having an HLB value selected from the range of 8 to 12 relative to the total amount of the vehicle.
1-3 except for ethylene glycol monolaurate)
The mixture is agitated and mixed in the presence of 0% by weight so that the aqueous vehicle exhibits a shear thinning property and a viscosity of 2%.
5 to 160 m. Pa. s (value at a rotation speed of 100 rpm in an EM type rotational viscometer, 25 ° C.), and a shear thinning viscosity index is adjusted to a range of 0.1 to 0.6. Preparation method. 2. The nonionic surfactant (polyethylene)
(Excluding glycol glycol monolaurate) is prepared so that a phase in a dispersed state in the form of fine particles of 2 μm or less and a phase in a substantially dissolved state are mixed in the ink composition. The method for preparing a shear thinning water-based ballpoint pen ink according to claim 1. 3. A nonionic surfactant (polyethylene glycol monolaurate) containing 1 to 35% by weight of a colorant and 2 to 35% by weight of a water-soluble polar solvent and having an HLB value in the range of 8 to 12.
1 to 30 wt% excluding the rate), the balance is water and adjusting additives, viscosity 25～160M. Pa. s (EM
Value at a rotational speed of 100 rpm in a rotational viscometer of the mold, 25
C.), the shear thinning index is in the range of 0.1 to 0.6, and the phase in which the surfactant is dispersed in the form of fine particles and the phase in which the molecule is dissolved are in a mixed state. Shear thinning aqueous ball-point pen ink composition. 4. The nonionic surfactant according to any one of claims 1 to 3 has at least one or more hydroxyl groups in the molecule. 5. The nonionic surfactant according to any one of claims 1 to 4 is liquid or pasty in a temperature range from room temperature to room temperature or higher. 6. The colorant according to claim 1 or 3 is a reversible thermochromic microcapsule pigment. 7. The colorant is a reversible thermochromic microcapsule pigment, and a homogeneous compatible solution containing an electron-donating organic compound, an electron-accepting compound and a reaction medium for controlling the color change temperature as essential components is used as a wall film. Particle size distribution is 0.5μ
The shear-thinning aqueous ball-point pen ink composition according to claim 3, which is a pigment occupying 95% by volume or more in a range of m to 20 µm. 8. A reversible thermochromic microcapsule pigment occupying 95% by volume or more in a particle distribution of 0.5 μm to 20 μm in a range of 5 to 35% by weight (solid content) and an HLB value of 8 to 12.
1 to 30% by weight of the nonionic surfactant, 2 to 35% by weight of the water-soluble polar solvent, and the balance water and the adjusting additive, and the viscosity is 30 to 160 m. Pa. A shear thinning viscosity water-based ball ink composition having a shear thinning index of 0.1 to 0.6 in the range of s (value at 100 rpm in an EM type rotary viscometer). 9. The reversible thermochromic microcapsule pigment is a pigment having a wall film formed by an interfacial polymerization or an interfacial polycondensation method having a depression on at least a part of the outer surface thereof, thereby reducing the shearing force. Viscous aqueous ballpoint pen ink composition. 10. A ball-point pen configured such that the ink stored in the ink storage portion can be drawn out from a tip holding a ball rotatably, and the ink can be written in the ink storage portion. An aqueous ball-point pen characterized in that the shear thinning aqueous ink composition for a ball-point pen is stored in a direct liquid state without an ink flow rate adjusting member. 11. The water-based ballpoint pen according to claim 10, wherein the ink containing portion is composed of a pipe, and an ink follower is arranged at a rear end portion of the ink composition for shear thinning aqueous ballpoint pen in a contained state.