JP2009161654A - Water-based ballpoint pen ink composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous ink composition for ballpoint pen in which the dispersibility of titanium oxide is excellent and which is well in writing. <P>SOLUTION: In the aqueous ink composition for the ballpoint pen containing at least water, titanium oxide and a surfactant, the titanium oxide has 1 to 95 nm average particle diameter and the surface of the titanium oxide is subjected to surfactant treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an aqueous ballpoint pen ink composition, and more particularly to an aqueous ballpoint pen ink composition containing titanium oxide having good dispersibility.

  Conventionally, water-based ballpoint pens using titanium oxide are well known. In such an aqueous ballpoint pen containing titanium oxide, it is necessary to blend titanium oxide at a high concentration in order to obtain a clear handwriting when written on dark paper or the like.

  In addition, in order to improve the concealability and handwriting visibility, titanium oxide, which is an inorganic pigment having an average particle diameter of 0, 5 μm or more, was used, so that the specific gravity was large and settled with time in the ink. There was a problem.

In view of these problems, as an aqueous ball-point pen that suppresses sedimentation of titanium oxide and has good concealing properties, Japanese Patent Application Laid-Open No. 8-325503 “Aqueous Pigment Ink Composition for Core Writing Instruments”, Japanese Patent Application Laid-Open No. 10-44673. Japanese Laid-Open Patent Publication “Ballpoint Pen”, WO98 / 50473, “White Tone Pigment Ink for Aqueous Ballpoint Pen” and the like are disclosed.
"JP-A-8-325503" "Japanese Patent Laid-Open No. 10-44673" "WO98 / 50473 publication"

  However, in Patent Document 1, by setting the ink viscosity to 6000 to 50000 centipoise, there is an effect of suppressing the precipitation of titanium oxide, but as a water-based ink, the ink viscosity is very high, and ink follow-up failure occurs. This will result in poor handwriting such as blurring and line skipping in the handwriting, and poor writing quality.

  Moreover, in patent document 2, since there is much content of titanium oxide as 25 weight% or more, it does not carry out dispersion | distribution stabilization in ink, and titanium oxide will settle, and it will become a writing defect. Furthermore, titanium oxide having a conventional particle size is also a material used as an abrasive, and a rough feeling or paper hitting occurs during writing, resulting in poor writing quality. Further, the ball seat of the ball tip is worn, and the wear is remarkable, which causes blurring, line skipping, and poor writing on the handwriting.

  Furthermore, in Patent Document 3, since the particle size of titanium oxide is 150 nm or more, the concealability is good, but the specific gravity of titanium oxide is high, and there is a problem that precipitation is likely to occur over time.

  An object of the present invention is to provide an ink composition for a water-based ballpoint pen having good dispersibility of titanium oxide in ink and good writing quality.

In order to solve the above problems, the present invention
“1. An aqueous ballpoint pen ink composition containing at least water, titanium oxide, and a surfactant, wherein the titanium oxide has an average particle diameter of 1 to 95 nm, and the titanium oxide has an interface on the surface. The ink composition for water-based ballpoint pens according to claim 1, wherein the composition is subjected to an activator treatment.
2. 2. The water-based ballpoint pen ink composition according to item 1, wherein the titanium oxide is surface-treated with a silicon-based surfactant.
3. The water-based ballpoint pen ink composition according to item 1 or 2, wherein the titanium oxide content is 0.5 to 30.0% by mass relative to the total mass of the ink composition.
4). The surfactant is a phosphate ester surfactant, and the content of the phosphate ester surfactant is 0.1 to 5.0% by mass with respect to the total mass of the ink composition. 2. The ink composition for oil-based ballpoint pens according to claim 1. Is.

  The present invention is an aqueous ballpoint pen ink composition comprising at least water, titanium oxide, and a surfactant, wherein the titanium oxide has an average particle size of 1 to 95 nm, and the titanium oxide has an interface on the surface. By the fact that it was treated with an activator, it was possible to provide an aqueous ballpoint pen ink composition having good dispersibility of titanium oxide in ink and good writing quality.

  The first feature of the present invention is that titanium oxide having an average particle diameter of 1 to 95 nm is contained and the surface of titanium oxide is treated with a surfactant.

  Titanium oxide is used as a concealing white colorant, but because of its high specific gravity, it is inferior in dispersibility stability in ink, tends to settle, and has poor writing due to clogging at the tip of the chip. Is likely to occur. Therefore, when titanium oxide is contained, it is important to consider the dispersion stability of titanium oxide.

  Further, since titanium oxide is contained in the ink composition, resistance is generated between the ball-point pen tip ball and the ball seat during writing, and there is a tendency that a rough feeling or paper hitting occurs and the writing quality is deteriorated. Therefore, when titanium oxide is contained, it is important to consider improvement in writing quality.

  The smaller the particle size of titanium oxide, the better the dispersibility and the better the ink aging stability. However, when the average particle size is less than 1 nm, the particle size is too small to make it difficult to manage the particle size in the manufacturing process. Therefore, when productivity is taken into consideration, it is not practical. On the other hand, if it exceeds 95 nm, the dispersibility of titanium oxide becomes unstable and sedimentation occurs. Furthermore, resistance is generated between the ball of the ball-point pen tip and the ball seat during writing, and a rough feeling and paper hitting are generated, so that the writing quality is deteriorated and the handwriting tends to be blurred and skipped. Therefore, in order to improve the dispersibility of titanium oxide, the average particle size needs to be 1 to 95 nm, and in order to obtain better dispersibility, oxidation with an average particle size in the range of 1 to 50 nm is required. It is necessary to use titanium.

  Furthermore, when the surface of the titanium oxide is surface-treated with a surfactant, the surface activity is suppressed, so that there is an effect that aggregation and sedimentation of titanium oxide in the ink composition can be suppressed. Further, since the surface is treated with a surfactant, the lubricity is improved between the ball of the ball-point pen tip and the ball seat at the time of writing, so that a synergistic effect that improves the writing quality can be obtained.

  Examples of the surfactant to be surface-treated include silicon-based, fluorine-based, phosphate ester-based, and acetylene glycol-based surfactants, but a silicon-based interface having an effect of further suppressing surface activity. Activators are most preferred.

  Specifically, micro cut powder (average particle size: 10 to 20 nm, silicon surfactant surface treatment, manufactured by Polar Kasei Kogyo Co., Ltd.), Idemitsu Titania I-TS (average particle size: 10 to 30 nm, Idemitsu Manufactured by Kosan Co., Ltd.), Tynock A-6, M-6, AM-15, H-30, R-30, A-100 (average particle size: 5-95 nm, manufactured by Taki Chemical Co., Ltd.) ) And the like, and those obtained by processing them. These may be used alone or in combination of two or more.

  Further, if the content of titanium oxide exceeds 30.0% by mass with respect to the total mass of the ink composition, it is difficult to obtain good writing quality and writing performance, and if it is less than 0.5% by mass, sufficient Handwriting visibility and concealment cannot be obtained. Therefore, the content of titanium oxide is preferably in the range of 0.5 to 30.0% by mass with respect to the total mass of the ink composition. More preferably, it is 5.0-20.0 mass% with respect to the ink composition whole quantity.

    The second feature of the present invention is to contain a surfactant in the ink composition in order to improve the writing quality, to improve the lubricity between the ball and the chip body, and to obtain a smooth writing feeling.

  As described above, when titanium oxide is contained in the ink composition, resistance is generated between the ball of the ball-point pen tip and the ball seat at the time of writing, and there is a tendency that a rough feeling or paper hitting occurs and the writing quality is deteriorated. Therefore, it is necessary to treat the surface of titanium oxide with a surfactant, and to include a surfactant in the ink composition to improve the lubricity between the ball and the chip body and improve the writing quality. .

  Examples of the surfactant used in the present invention include surfactants such as phosphate ester surfactants, silicon surfactants, fluorine surfactants, and acetylene glycol surfactants. These surfactants are used to improve the writing quality because the lubricity between the ball and the chip body can be improved and a smooth writing feel can be obtained. Among them, those having a phosphate group have an adsorptive power to metals and are adsorbed to a ball or a chip body, so that they are more lubricious than other types of surfactants and phosphorous. It is more preferable to use an acid ester surfactant. These may be used alone or in combination of two or more.

  Phosphate ester surfactants include polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphate monoester, polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphate diester, phosphate triester, Alternatively, there are derivatives thereof, but these phosphate surfactants may be used alone or in combination of two or more. Among these, in view of ink aging stability, it is most preferable to use polyoxyethylene alkyl ether or polyoxyethylene alkyl aryl ether phosphoric acid monoester or phosphoric acid diester.

Examples of the phosphoric ester surfactant include styrenated phenols, nonylphenols, lauryl alcohols, tridecyl alcohols, octylphenols, short chain alcohols, and the like. Further, among this, styrenated phenol, nonylphenol type, phenyl skeleton of octylphenol system such as _{(C 6 H 5 -, C} 6 H 4 -, C 6 H 3 - , etc.) phosphoric acid ester-based surfactant having a can, Since the phenyl skeleton forms a three-dimensional structure, it has the effect of causing steric hindrance compared to other systems, and the lubricity is somewhat inferior, and the improvement in writing quality is small. It is more preferable to use a tridecyl alcohol type or a short chain alcohol type.

  Specific examples of the phosphate ester-based surfactant include Prisurf A208B (lauryl alcohol), A219B (lauryl alcohol), A213B (lauryl) from the Prisurf series (Daiichi Kogyo Seiyaku Co., Ltd.). Alcohol), A210B (Lauryl alcohol), A215C (Tridecyl alcohol), Plysurf A212C (Tridecyl alcohol), A208F (Short chain alcohol), A208S (Synthetic alcohol), A208N (Synthetic alcohol type). These surfactants may be used alone or in combination of two or more.

  Further, if the content of the phosphate ester-based surfactant is less than 0.1% by mass relative to the total amount of the ink composition, the desired lubricity may not be obtained in the ink, and 5.0% by mass If it exceeds 1, the ink aging may become unstable, so 0.1 to 5.0% by mass is preferable with respect to the total amount of the ink composition. More preferably, 0.5-3.0 mass% is suitable with respect to the ink composition whole quantity.

  A water-soluble organic solvent may be used in consideration of water dissolution stability and prevention of water evaporation drying. The water-soluble solvent is added for the purpose of suppressing water evaporation at the tip of the ballpoint pen tip, and organic solvents such as glycol and glycol ether generally used for aqueous ballpoint pens can be used, but butyl cellosolve (boiling point 171 ° C.), etc. Those having a boiling point of less than 180 ° C. have a high vapor pressure at room temperature, and easily evaporate with moisture. Also, glycerin (boiling point 290 ° C.), diethylene glycol (boiling point 245 ° C.), triethylene glycol (boiling point 276 ° C.), dipropylene glycol (boiling point 225 ° C.), propylene glycol (boiling point 188 ° C.), ethylene glycol (boiling point 198 ° C.), Those having a boiling point of 180 ° C. or higher are generally preferable because they have a low vapor pressure and are difficult to evaporate with moisture. Furthermore, those having a boiling point of 250 ° C. or higher such as glycerin are more preferable because they are more difficult to evaporate and are excellent in stability over time.

  Moreover, you may use together inorganic, organic, a processed pigment, etc. as a coloring agent. Specifically, carbon black, aniline black, ultramarine, yellow lead, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium, triphenylmethane, perinone, perylene, glyoxazine, aluminum pigment, Examples include pearl pigments, fluorescent pigments, phosphorescent pigments, and complementary color pigments. In addition, microcapsules in which hollow resin particles or colored bodies in which pigments are dispersed in a medium as colored resin particles are encapsulated or solidified in a shell made of a resin wall film-forming substance by a known microencapsulation method A pigment may be used. These pigments may be used alone or in combination of two or more. If desired, direct dyes, acid dyes, basic dyes, metal-containing dyes, and various salt-forming dyes may be used in combination.

  A shear thinning agent may be used as a viscosity modifier. Specific examples include shear thinning agents such as xanthan gum, crosslinked acrylic acid polymer, crosslinked acrylamide polymer, succinoglycan, guar gum, and welan gum.

  In addition, as other additives, pH adjusters such as triethanolamine, humectants such as urea and sorbit, rust inhibitors such as benzotriazole, and antibacterial agents such as 1,2 benzoisothiazolin-3-one should be added. Can do. These may be used alone or in combination of two or more. Fixing agents and dispersants can also be added as appropriate. Water-soluble resins include acrylic resins, alkyd resins, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, etc., and resin emulsions such as acrylic resins, urethane resins, styrene- A butadiene resin, a polyester resin, a vinyl acetate resin, or the like can be added.

Next, an Example is shown and this invention is demonstrated.
Example 1
57.0% by weight of water
Water-soluble organic solvent (glycerin) 18.0% by mass
Phosphate ester surfactant (trade name; Prisurf A-208N) 2.5% by mass
Titanium oxide (trade name; micro cut powder, average particle size; 10 to 20 nm)
20.0% by mass
pH adjuster (triethanolamine) 2.0% by mass
Antibacterial agent (1,2 benzoisothiazolin-3-one) 0.5% by mass
Shear thinning agent (succinoglycan) 0.30% by mass

  , Titanium oxide (micro cut powder (average particle size: 10-20 nm, manufactured by Polar Chemical Industries, Ltd.)), dispersant (phosphate ester surfactant), water-soluble organic solvent (glycerin), bead mill, ball mill After sufficiently dispersing using a disperser such as the above, centrifugal separation is performed to remove coarse components to obtain a pigment dispersion.

  Add the pigment dispersion, water, water-soluble organic solvent, phosphate ester surfactant (Pricesurf A-208N (Daiichi Kogyo Seiyaku Co., Ltd.)), pH adjuster and antibacterial agent with a magnet hot stirrer. Stir warm to make base ink.

  Then, while heating the base ink prepared above, the shear thinning agent was added and mixed and stirred thoroughly using a homogenizer stirrer until uniform, and then filtered using filter paper. 1 aqueous ballpoint pen ink composition was obtained.

Examples 2-7
As shown in Table 1, water-based ink compositions of Examples 2 to 7 were obtained in the same procedure as in Example 1 except that each component was changed to a blend. Table 1 shows the measurement and evaluation results.

Comparative Examples 1-5
The composition of the ink is as shown in Table 2, and Table 2 shows the measurement and evaluation results.

Test and Evaluation In the titanium oxide dispersibility test, evaluation was performed by the following test methods using the water-based ink compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 5.
In addition, in the writing taste test, the tip of the ink containing cylinder is provided with a ballpoint pen tip having a silicon carbide ball having a ball diameter of φ0.7 mm that is rotatably held in the ball holding chamber of the chip body. A refill in which a water-based ink composition and a grease-like ink follower prepared in Examples 1 to 1 and Comparative Example 1 were directly filled in a cylinder was used as a gel ink ballpoint pen (trade name: G-3) manufactured by Pilot Corporation. ) Was prepared, and evaluated using JIS P3201 writing paper A as a writing test paper.

Titanium oxide dispersibility test: Each sample was placed in a 15 mm diameter open / close glass test tube, allowed to stand at room temperature for 1 month, and then collected in an appropriate amount.
Titanium oxide uniformly dispersed ・ ・ ・ ○
Titanium oxide sedimentation ・ ・ ・ ×

Written taste: A hand-written sensory test was performed and evaluated.
Smooth and good ・ ・ ・ ○
Heavy and inferior ・ ・ ・ ×

  From the results of Table 1, in Examples 1 to 7, good performance was obtained for both the titanium oxide dispersibility test and writing quality.

  From the results in Table 2, in Comparative Examples 1 to 5, titanium oxide was precipitated due to titanium oxide having an average particle diameter of 260 nm.

In Comparative Examples 4 and 5, since the phosphate ester surfactant was not added, there was a feeling of roughness when writing and the writing quality was poor. Since hollow resin particles and / or colored resin particles were not used in combination, there was a feeling of roughness when writing and the writing quality was poor.

  In the present embodiment, the coil spring that presses the ball is not provided on the inner wall of the tip end edge of the ballpoint pen tip, but the effect of suppressing ink sag is improved by providing the coil spring, which is more preferable.

  The ink viscosity of the water-based ink composition of the present invention is not particularly limited, but is 10 to 3000 mPa · s at 20 ° C. and 1.92 rpm in order to improve the writing quality and suppress the precipitation of titanium oxide. It is preferable to set to s.

  The present invention relates to a water-based ballpoint pen, and more specifically, by using a water-based ballpoint pen ink composition characterized in that a titanium oxide having an average particle size of 1 to 95 nm and a surfactant are used in combination. An aqueous ballpoint pen ink composition having good dispersibility and good writing quality can be provided. Therefore, it can be widely used as a ballpoint pen, such as a cap type and a knock type.

Claims (4)

An aqueous ballpoint pen ink composition containing at least water, titanium oxide, and a surfactant, wherein the titanium oxide has an average particle diameter of 1 to 95 nm, and the titanium oxide has a surfactant treatment on the surface. The water-based ballpoint pen ink composition according to claim 1, wherein The water-based ballpoint pen ink composition according to claim 1, wherein the titanium oxide is surface-treated with a silicon-based surfactant. 3. The aqueous ballpoint pen ink composition according to claim 1, wherein the titanium oxide content is 0.5 to 30.0 mass% with respect to the total mass of the ink composition. The surfactant is a phosphate ester surfactant, and the content of the phosphate ester surfactant is 0.1 to 5.0% by mass with respect to the total mass of the ink composition. 2. The ink composition for oil-based ballpoint pens according to claim 1.