JP2013119253A - Water-based ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based ballpoint pen having a smooth writing feeling, suppressing abrasion of a ball seat, and excellent in ink stability with time.SOLUTION: The water-based ballpoint pen includes a ballpoint pen tip rotatably holding a ball in a ball holding chamber of a tip body made of a stainless steel directly or through a tip holder at the distal end part of an ink storing cylinder, the ball having a ball diameter of ≤0.4 mm. The water-based ballpoint pen is characterized in that a water-based ballpoint pen ink composition including at least water, a coloring agent, a phosphate-based surfactant with a HLB (hydrophile-lipophile balance) of ≥10, and a solvent with a solubility parameter of 12-18, is directly filled into the ink storing cylinder.

Description

  The present invention relates to a water-based ballpoint pen, and more particularly to a water-based ballpoint pen that has a smooth writing feel, suppresses wear of a ball seat, and is excellent in ink aging stability.

    Conventionally, a ballpoint pen provided with a ballpoint pen tip using a tip body made of a stainless steel material is well known. This uses a chip body made of stainless steel in consideration of wear resistance, corrosion resistance, cost, and the like. Further, in order to improve the writing feeling, and to avoid the occurrence of blurring of handwriting and line skipping, Japanese Patent Application Laid-Open No. 2006-282870 “Water-based ink composition for ballpoint pens” and Japanese Patent Application Laid-Open No. 7-62288 “Ink composition for water-based ballpoint pens”. In Japanese Patent Application Laid-Open No. 2003-192972 “Water-based ballpoint pen ink”, water-based ballpoint pen ink compositions containing various lubricants have been proposed.

"JP 2006-282870 A" "JP-A-7-62288" "Japanese Patent Laid-Open No. 2003-192972"

  In Patent Document 1, since an isoprene sulfonic acid-acrylic acid copolymer is contained, ink can be stably discharged without interruption, so that writing can be performed with light writing, and line breaks and blurring of handwriting can be prevented. Inhibiting, Patent Document 2 discloses that by containing dibenzylidene sorbitol, ink can flow smoothly by rotation of the ball, thereby enabling smooth writing and improving writing performance such as blurring. However, in Patent Document 3, by containing an N-acylamino acid and N-acylmethyltaurine, the friction between the ball and the tip seat is reduced during the rotation of the ball during writing by adsorbing to the seat of the tip. Therefore, it is disclosed that the writing quality is improved. As described above, although a somewhat smooth writing feeling was obtained, the ink aging stability due to the dissolution stability in the ink was poor, and there was a problem that precipitates were likely to be generated. In particular, in recent ultra-fine water ballpoint pens of φ0.4 or less, since the contact area between the ball and the ball seat is small, the writing quality is poor, the wear of the ball seat is likely to be poorly written, and the problem is solved. Was desired.

  The object of the present invention is to solve the above-mentioned problems, and is a water-based ballpoint pen having a ball diameter of 0.4 mm or less, has a smooth writing feeling, suppresses wear of the ball seat, and is stable over time with ink. It is to provide an excellent water-based ballpoint pen.

In order to solve the above problems, the present invention
“1. A ballpoint pen tip having a ball rotatably held in a ball holding chamber of a chip body made of a stainless steel material is provided directly or via a tip holder at the tip of the ink containing cylinder, and the ball diameter is 0. A water-based ballpoint pen that is 4 mm or less, and is an ink composition for water-based ballpoint pens that includes at least water, a colorant, a phosphate ester-based surfactant having an HLB of 10 or more, and a solvent having a solubility parameter of 12 to 18 in the ink containing cylinder. A water-based ballpoint pen characterized by packing things directly.
2. The water-based ballpoint pen according to item 1, wherein the phosphate ester surfactant of HLB 10 or higher is a linear alcohol phosphate ester surfactant.
3. The aqueous ballpoint pen according to item 1 or 2, wherein the phosphate ester-based surfactant having an HLB of 10 or more is 0.1 to 5.0% by mass. .
4). The water-based ballpoint pen according to any one of Items 1 to 3, wherein the ball is made of a cemented carbide material. Is.

  In the water-based ballpoint pen having a ball diameter of 0.4 mm or less, the present invention improves the lubricity, has a smooth writing feeling, suppresses the wear of the ball seat, and does not generate precipitates. An aqueous ballpoint pen excellent in stability over time could be provided.

  A feature of the present invention is that in a water-based ballpoint pen having a ball diameter of 0.4 mm or less equipped with a ballpoint pen tip using a tip body made of stainless steel material, a phosphate ester-based surface activity of HLB 10 or more in an ink containing cylinder A water-based ballpoint pen ink composition that uses a combination of an agent and a solvent having a solubility parameter of 12 to 18 is directly packed.

  As the lubricant used in the present invention, a phosphate ester type surfactant is used in consideration of smooth writing feeling and suppression of wear of the ball seat by further improving the lubricity. This is because the phosphate group has an adsorptive power to metals and adsorbs to balls, chip bodies, etc., so it has better lubricity and better lubrication effect than other types of surfactants. It is for having. In particular, among metals, since the phosphate group is easily adsorbed to the stainless steel material, the lubricating effect of the phosphate ester surfactant is further obtained. Use.

  In addition, the lubricity can be improved to some extent by using a phosphoric acid ester type surfactant alone. However, in the case of a ball having a ball diameter of 0.4 mm or less, the contact area between the ball and the ball seat is small and it takes up a unit area. Deterioration of writing feeling and wear of the ball seat are likely to progress due to increased load, but in order to solve these problems, we are eagerly studying whether it is possible to improve lubricity and improve ink aging stability. As a result, by selecting a specific phosphate ester surfactant and a specific solvent, and improving lubricity, it has a smooth writing feel, suppresses wear of the ball seat, and improves ink aging stability. It turns out that it is possible to excel.

  As for the phosphate ester type surfactant, it is necessary to use HLB 10 or more in consideration of lubricity and ink aging stability. This is because a phosphate ester-based surfactant having an HLB of less than 10 has a low HLB value and thus has a high lipophilicity and improves the lubricity of the ball. Phosphate ester surfactants less than HLB10 react with metal ions such as manganese ions and chromium ions eluted from the inside of the chip body to easily form highly lipophilic metal salts, which are soluble in aqueous inks. It is because it is easy to be inferior and the problem which the deposit by a metal salt generate | occur | produces easily arises. In particular, when the ball diameter is 0.4 mm or less, the ink discharge port is small, and the precipitates are clogged, resulting in poor writing.

  In addition, the solvent is used in consideration of the dissolution stability of the colorant, the dissolution stability of water, the suppression of water evaporation, etc., but when using a phosphate ester surfactant of HLB10 or higher as in the present invention. In order to further improve the lubricity, it is necessary to use a solvent having a solubility parameter of 12 to 18. This is because the solvent having a solubility parameter of less than 12 has poor compatibility between the solvent and water, resulting in poor ink aging stability, and in the case of a solvent having a solubility parameter of more than 18, in aqueous ink, The phosphate ester surfactant of HLB10 or more has improved solubility in water, so that the amount of phosphate groups adsorbed on the chip body of the stainless steel material is small, so that a desired lubricating effect can be obtained. Absent. Therefore, in an aqueous ballpoint pen having a ball diameter of 0.4 mm or less, it is necessary to use a phosphate ester surfactant having an HLB of 10 or more and a solvent having a solubility parameter of 12-18.

  In addition, among the phosphate ester surfactants of HLB10 or higher, linear alcohol-based phosphorus is considered in consideration of improving the lubricity and improving the smooth writing feeling and the ball seat wear suppression. Acid ester surfactants are preferred. This includes styrenated phenol-based, nonylphenol-based, lauryl alcohol-based, tridecyl alcohol-based, octylphenol-based, short-chain alcohol-based, etc. If it has, the lubricity tends to be affected by steric hindrance, and therefore it is preferable to use a linear alcohol lauryl alcohol, tridecyl alcohol, or short chain alcohol. Furthermore, it is most preferable to use a lauryl alcohol-based phosphate surfactant because the lubricating performance and the dissolution in ink tend to be stable and the ink aging tends to be stable. You may use these individually or in mixture of 2 or more types.

Specific examples of phosphate ester surfactants having an HLB of 10 or more include Prisurf A212E (HLB value: 10, nonylphenol), Prisurf A217E (HLB) from the Prisurf series (Daiichi Kogyo Seiyaku Co., Ltd.). Value: 15, nonylphenol type), A213B (HLB value: 12, lauryl alcohol type), A215C (HLB value: 11, tridecyl alcohol type), A219B (HLB value: 16, lauryl alcohol type), etc. It is done. These phosphate ester surfactants may be used alone or in combination of two or more.
In addition, HLB can be calculated | required from HLB = 7 + 11.7log (Mw / Mo) and (Mw: molecular weight of a hydrophilic group, Mo: molecular weight of a lipophilic group) as a general formula.

  The content of the phosphate ester surfactant having an HLB of 10 or more is preferably 0.1 to 5.0% by mass with respect to the total amount of the ink composition. If the addition amount is less than 0.1% by mass with respect to the total amount of the ink composition, the desired lubricity tends to be difficult to obtain, the writing feeling tends to be poor, and there is a tendency for blurring to occur in the handwriting. If it exceeds 0.0% by mass, the ink aging tends to become unstable, so 0.1 to 5.0% by mass is preferable with respect to the total amount of the ink composition. Furthermore, if considering lubricity and ink aging stability, 0.5 to 3.0% by mass is most preferable.

  Moreover, about the solvent whose solubility parameter is 12-18, since there is much adsorption amount of a phosphate group and a lubrication effect is easy to be acquired, the solvent whose solubility parameter is 12-16 is preferable. When the content of the solvent having a solubility parameter of 12 to 18 is less than 5.0% by mass, the desired lubricity tends to be difficult to obtain, and the dissolution stability of the colorant tends to be difficult to obtain. If it exceeds 5% by mass, the writing quality and blurring are likely to be affected, so 5.0 to 40.0% by mass is preferable with respect to the total amount of the ink composition. In consideration of lubricity, 10.0 to 30.0% by mass is most preferable.

  Moreover, a coloring agent can be used in combination with dye, a pigment, etc. suitably. As the dye, direct dyes, acid dyes, basic dyes, metal-containing dyes, various salt-forming dyes, and the like can be used. Examples of pigments include inorganic, organic, and processed pigments. Specifically, carbon black, aniline black, ultramarine, yellow lead, titanium oxide, iron oxide, phthalocyanine, azo, quinacridone, quinophthalone, selenium , Triphenylmethane, perinone, perylene, glyoxazine, aluminum pigment, pearl pigment, fluorescent pigment, phosphorescent pigment, and complementary color pigment. These colorants may be used alone or in combination of two or more. The content is preferably 1 to 20% by mass relative to the total amount of the ink composition.

  In addition, in order to improve the temporal stability of the colorant, pH adjusters, antibacterial agents such as 1,2 benzoisothiazolin-3-one, moisturizers such as urea and sorbit, and rust preventive agents such as benzotriazole A chelating agent such as ethylenediaminetetraacetic acid can be added. Further, silicon-based, acetylene glycol-based, and fluorine-based surfactants other than the phosphate ester surfactants can be added to improve handwriting dryness, wettability, and the like. In addition, acrylic resins, alkyd resins, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, etc. as water-soluble resins, and acrylic resins, urethane resins, styrene-butadiene resins, polyester resins, vinyl acetate resins as resin emulsions. For adjusting the viscosity of the ink such as a resin, a shear thinning agent such as a cross-linked acrylic acid polymer, xanthan gum, succinoglycan, or a cellulose derivative can be added. These can be used alone or in combination of two or more.

The ink viscosity is not limited, but considering a smoother writing feel, using a Brookfield DV-II viscometer (CPE-42 rotor) in an environment of 20 ° C., At a shear rate of 384.0 sec ⁻¹ , it is preferably 50 mPa · s or less, and more preferably 20 mPa · s to 50 mPa · s.

  The ball material is not particularly limited, and examples thereof include cemented carbide, silicon carbide, alumina, zirconia, ruby, silicon nitride, and resin balls. In particular, cemented carbide balls are mainly composed of tungsten carbide and sintered with iron-based metals such as Fe, Co, Ni, etc., and phosphate groups are easily adsorbed. This is preferable because a lubricating effect can be further obtained.

Next, an Example is shown and this invention is demonstrated.
Example 1
Water 65.5 parts by mass Solvent (solubility parameter value: 16) 20.0 parts by mass Lubricant (phosphate ester surfactant) 1.0 part by mass pH adjuster (triethanolamine) 1.5 parts by mass humectant 5.0 parts by mass rust preventive (benzotriazole) 0.5 parts by mass antibacterial agent (1,2 benzoisothiazolin-3-one) 0.5 parts by mass colorant (direct black 154) 6.0 parts by mass shear reduction Viscosity imparting agent (xanthan gum) 0.40 parts by mass

  First, water, a solvent, a phosphate ester surfactant, a pH adjuster, a humectant, a fungicide, a rust inhibitor, and a colorant are heated and stirred with a magnet hot stirrer to prepare a 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. The ink viscosity in Example 1 was measured using a Brookfield DV-II viscometer (CPE-42 rotor) at 20 ° C. and a shear rate of 384 sec ⁻¹ (rotation speed: 100 rpm). It was 45 mPa · s when measured.

  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. An ink composition for a water-based ballpoint pen used in No. 1 was obtained. Further, a ballpoint pen tip made of a stainless steel material rotatably holding a cemented carbide ball having a diameter of 0.38 mm was mounted via a tip holder, and the water-based ballpoint pen ink composition was directly packed inside the ink containing cylinder. The refill was mounted on a gel ink ballpoint pen (trade name: G-knock) manufactured by Pilot Corporation to obtain an aqueous ballpoint pen of the present invention.

Examples 2-7
Except that the ink formulation and the ball diameter were changed as shown in Table 1, water-based ballpoint pens of Examples 2 to 7 were obtained in the same procedure as Example 1. Table 1 shows the measurement and evaluation results.

Comparative Examples 1-7
Aqueous ballpoint pens of Comparative Examples 1 to 7 were obtained in the same procedure as in Example 1 except that the composition of the ink and the ball diameter were changed as shown in Table 2. Table 2 shows the measurement and evaluation results.

Tests and Evaluations The following tests and evaluations were performed using the aqueous ballpoint pens prepared in Examples 1 to 7 and Comparative Examples 1 to 7. The writing feeling and the abrasion resistance test were evaluated by the following test method using JIS P3201 writing paper A as a writing test paper.

Writing sensation: A ballpoint refill was allowed to stand in a room temperature environment for 2 weeks, and then evaluated by a handwritten sensory test.
Very smooth ・ ・ ・ ◎
Smooth thing ○○
Somewhat heavy ・ ・ ・ △
Heavy and slippery

Abrasion resistance test: The wear of the ball seat after the writing test was measured with a running test machine with a load of 100 gf, a writing angle of 65 °, and 4 m / min.
Ball seat wear less than 10μm ・ ・ ・ ◎
Ball seat wear of 10 to 20 μm
Ball seat wear of 20-30 μm
Ball seat wear exceeding 30 μm ・ ・ ・ ×

Ink aging test: After the ballpoint refill was left for 3 months in an environment of 50 ° C. and 0% humidity, the ink in the chip body was observed with a microscope.
Good without deposits ... ◎
Slightly generated precipitates, but no problem in practical use
Precipitate is present and causes scumming or poor writing ・ ・ ・ ×

  From the results shown in Table 1, in Examples 1 to 7, good writing feeling, abrasion resistance test and ink aging test were obtained, or performance at a level having no practical problem was obtained.

  From the results shown in Table 2, in Comparative Examples 1, 2, and 5, since a phosphate ester-based surfactant having an HLB of less than 10 was used, the writing feeling was poor.

  In Comparative Example 3, since a solvent having a solubility parameter exceeding 18 was used, precipitates were generated.

  In Comparative Example 4, since a solvent having a solubility parameter of less than 12 was used, the writing feeling was slightly heavy.

  In Comparative Example 6, since the phosphate ester surfactant was not used, the writing feeling and the abrasion resistance test were bad.

  In Comparative Example 7, since a solvent having a solubility parameter of 12 to 18 was not used, the writing feeling was slightly heavy.

  The present invention can be used as a water-based ballpoint pen, and more specifically, can be widely used as a water-based ballpoint pen of a cap type or a knock type filled with the ink composition for water-based ballpoint pens.

Claims (4)

The tip of the ink storage cylinder is equipped with a ballpoint pen tip that is rotatably held in a ball holding chamber of a tip body made of stainless steel, directly or via a tip holder, and the ball diameter is 0.4 mm or less. A water-based ballpoint pen, wherein an ink composition for a water-based ballpoint pen comprising at least water, a colorant, a phosphate ester surfactant having an HLB of 10 or more, and a solvent having a solubility parameter of 12 to 18 is directly placed in the ink container. A water-based ballpoint pen characterized by stuffing. The aqueous ball-point pen according to claim 1, wherein the phosphate ester-based surfactant having an HLB of 10 or more is a linear alcohol phosphate ester-based surfactant. The water-based ballpoint pen according to claim 1 or 2, wherein the phosphate ester-based surfactant having an HLB of 10 or more is 0.1 to 5.0% by mass relative to the total mass of the ink composition. The water-based ballpoint pen according to any one of claims 1 to 3, wherein the ball is made of a cemented carbide material.