JP2000080317A - Pigmented ink composition for use in water-based ball- point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigmented ink compsn. for use in a water-based ball- point pen to give an extremely good writing touch, not only excellent in a long-term stability and lubricity, causing no wear to the ball seat of the metallic tip, maintaining a uniform supply of ink while writing, and offering written lines with a uniform density and a long writing distance but also causing neither ink blurring nor dripping from the top of the metallic tip, and having an effect to contain corrosion of the metallic tip. SOLUTION: This pigmented ink compsn. for use in a water-based ball-point pen comprises a water-soluble resin and a water-soluble solvent, and contains, as an essential component, a nonionic fluorine-contg. surfactant, ammonium oleate and a polyoxyethylene alkyl ether phosphate. Its surface tension is adjusted in the range of 25-30 dyn/cm, and its pH value, in the range of 7.5-9.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous ballpoint pen ink using a pigment as a colorant.

[0002]

2. Description of the Related Art A conventional ballpoint pen having a metal tip as a brush end is composed of a dye, a resin, benzyl alcohol as a solvent,
There are those using an oil-based ink composition composed of phenyl glycol or oleic acid, and those using an aqueous ink composition composed of a dye and an aqueous medium. Poor water resistance. Therefore, an aqueous pigment ink composition using a pigment as a colorant has been proposed. However, the water-based pigment ink has a long-term stability because the pigment used as a coloring agent is insoluble in water and a solvent. Otherwise, a good writing feel cannot be obtained.

In order to solve the above-mentioned problems, for example, an ink containing a polyoxyethylene alkyl ether or a phosphoric acid monoester or diester of polyoxyethylene alkylphenyl ether (Japanese Patent Application Laid-Open No.
JP-A-66979), an ink containing a metal salt and / or an amine salt of N-acylsarcosine.
JP-A-2-27479), an ink containing a polyether polyol having a primary or secondary hydroxyl group at a molecular terminal (see JP-A-62-227372), and an ink containing a polyglycerin fatty acid ester (see JP-A-62-227372). JP-A-2-38474), those containing an organic phosphate (see JP-A-1-49432),
Ink containing alkali metal salt and / or amine salt of N-acylmethyltauric acid (JP-A-4-16497)
No. 7, Japanese Patent Application Laid-open No. 7) has been proposed, but problems such as increased bleeding of the writing line and aggregation of the pigment occur. Therefore, an amount sufficient to obtain a sufficient lubricating effect is added. As the writing progresses, the ball seat is worn out and the writing feel deteriorates, and the writing line becomes dull, broken, and braille, and the writing state is extremely poor, and the drawbacks have not been sufficiently solved.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the drawbacks of the conventional pigment ink for water-based ball pens, to provide excellent long-term stability and lubricating properties. There is no abrasion, uniform ink outflow during writing, uniform writing line density, long writing distance, no ink bleed, no tip leakage from the metal tip,
Further, it is an object of the present invention to provide a pigment ink composition for an aqueous ballpoint pen, which has an effect of suppressing corrosion of metal chips and has an extremely good writing feel.

[0005]

As a result of various studies to solve the problems described above, the present invention provides a pigment ink composition for water-based ball pens containing a pigment, a water-soluble resin and a water-soluble solvent. Contains nonionic fluorine-containing surfactant, ammonium oleate and polyoxyethylene alkyl ether phosphate as essential components, and
Surface tension is in the range of 25-30 dym / cm, pH
By adjusting the value to be 7.5 to 9.0,
It has been found that the object can be achieved, and the present invention has been completed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nonionic fluorine-containing surfactant used in the present invention has a surface tension of 25 to 30 dyn / c of the aqueous pigment ink composition for ballpoint pens.
m is added to adjust to the range of m, and among the nonionic fluorine-containing surfactants, those represented by the following general formula (1), particularly those having a value of n of 10 to 20 are effective. is there. The pigment ink composition for a water-based ballpoint pen of the present invention can be used in the range of 0.01 to 0.1% by weight based on the total amount. When the amount added is less than 0.01% by weight, the surface tension of the ink composition becomes 30 dyn / cm or more, and when it exceeds 0.1% by weight, 25 dyn / cm.
cm or less, and a lubricating effect cannot be obtained, but although there is a lubricating effect, ink leaks spontaneously from the tip of the metal tip. I will.

[0007]

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[0008] Ammonium oleate and polyoxyethylene alkyl ether phosphate improve the writing feel because dissociating ions interact to form a layer between the inner surface of the metal chip, ie between the ball and ball seat. It is thought to be. Disadvantages that could not be solved by adding only ammonium oleate or polyoxyethylene alkyl ether phosphate, excellent long-term stability, and good writing feel were obtained by using a nonionic fluorine-containing surfactant, ammonium oleate, The problem could be solved by using oxyethylene alkyl ether phosphate in combination.

The amount of ammonium oleate can be added in the range of 0.2 to 1.0% by weight based on the total amount of the pigment ink composition for aqueous ballpoint pens of the present invention. 0.0 to the total amount of the pigment ink composition for aqueous ballpoint pens of the present invention.
It can be used in the range of 5 to 2.0% by weight. When ammonium oleate is added and polyoxyethylene alkyl ether phosphate is not added, ink stability is poor,
When stored in an atmosphere of 40 ° C. and a relative humidity of 60%, writing becomes impossible in 1 to 3 months. In the case where only polyoxyethylene alkyl ether phosphate is added and ammonium oleate is not added, if a ball-point pen filled with the ink composition is continuously used, the ball seat at the end of the ball-point pen is worn and the writing feel is reduced. Deteriorates, causing blurring and broken characters.

If the total amount of ammonium oleate and polyoxyethylene alkyl ether phosphate is less than 0.2% by weight, the formation of the layer is insufficient and the writing feel is insufficiently improved. If the content exceeds 3.0% by weight, the writing feel is improved, but the leakage occurs. The preferred total amount is in the range of 0.4 to 2.0% by weight based on the total amount of the pigment ink composition for water-based ballpoint pens of the present invention. Although it depends on the material,
1-2: 1.

[0011]

[Action] The mechanism by which good writing feel is obtained is not clear, but ions generated by the dissociation of ammonium oleate and polyoxyethylene alkyl ether phosphate form on the inner surface of metal chips, the surface of balls and pigment particles. It adsorbs while interacting with each other to create a better lubricating effect, and the nonionic fluorine-containing surfactant, olein is formed by the combined micelle formation of the anion generated by the dissociation and the nonionic fluorine-containing surfactant. It is considered that a better writing feel was obtained because a synergistic lubricating effect, which cannot be obtained by adding ammonium acid and polyoxyethylene alkyl ether phosphate alone, was obtained. When a cationic surfactant is used as the fluorine-containing surfactant, a synergistic lubricating effect cannot be obtained due to a charge canceling action. On the other hand, in the case of the anionic system, the charged ions become too large, and the osmotic pressure effect required for dispersion expected to achieve the object of the present invention cannot be obtained, causing separation of the ink composition.

The pH of the ink composition is adjusted to suppress the rust of the metal chips and to stabilize the water-soluble resin used. Triethanolamine, N
-Methyldiethanolamine, diisopropanolamine, monoethanolamine, triethylamine, etc., and the amount of the ink used is 7.5 to 9.
Add so as to be in the range of 0. When the pH value of the ink composition is less than 7.5, the writing feel and the state of the writing line are deteriorated depending on the material of the metal tip used for the ballpoint pen to be filled with the aqueous ballpoint pen ink composition of the present invention. In severe cases, rust is generated within a short period of time, and the ink inside the chip is agglomerated.

The pigment used in the pigment ink composition for water-based ball-point pens of the present invention is not particularly limited, and any one of inorganic and organic pigments used in ordinary pigment ink compositions for water-based ball-point pens can be used. can do. The amount used is 5 to 30% by weight, preferably 8 to 30% by weight, based on the total amount of the pigment ink composition for aqueous ballpoint pens of the present invention.
It is selected in the range of 20% by weight.

Examples of the water-soluble resin include a water-soluble acrylic resin, a cross-linked acrylic acid resin, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, carboxycellulose, hydroxymethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium alginate, and acetic acid. Copolymers of vinyl and polyvinylpyrrolidone are exemplified. These water-soluble resins can be used alone or as a mixture of two or more kinds.
It is contained in the range of weight%. This content is 0.1% by weight
If it is less than 0.4% by weight, the viscosity suitable for writing cannot be obtained, and if it exceeds 0.4% by weight, the viscosity of the ink composition becomes too high. The writing feel is heavy and the writing property is poor.

As the water-soluble solvent, one or a mixture of two or more of propylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, polyethylene glycol and the like can be used.
Usually, it is used in the range of 10 to 40% by weight.

Further, in addition to the above main components, commonly used pigment dispersants, rust preventives, preservatives, wetting agents and the like can be added and used. Examples of the pigment dispersant include acrylic / styrene copolymers, maleic acid / styrene copolymers, and neutralized salts thereof, and examples of the rust preventive include benzotriazole, tolyltriazole, and dicyclohexylammonium nitrate. Can be illustrated.
Examples of preservatives include sodium benzoate, potassium sorbate, sodium pentachlorophenol, and the like.
As the wetting agent, a hygroscopic substance such as urea or a urea derivative can be used.

[0017]

Next, the present invention will be described in detail with reference to examples. As examples of the aqueous pigment ink composition for ballpoint pens of the present invention, those having the compositions shown in Table 1 below were prepared.

[0018]

[Table 1]

In Examples 1 to 7 shown in Table 1, a water-soluble resin such as a cross-linked acrylic acid resin or hydroxypropylcellulose was added to a water-soluble solvent such as ethylene glycol or glycerin and water with vigorous stirring. Dissolve completely. Next, acrylic and pigment dispersant
After the styrene copolymer is added and the pigment is uniformly dispersed, ammonium oleate, sodium polyoxyethylene oleyl ether phosphate, and a nonionic fluorine-containing surfactant are added. Add further urea, benzotriazole, potassium sorbate additives and keep stirring vigorously. Finally, the pH value was adjusted to 7.5 to 9.0 by adding triethylamine or triethanolamine, and this was used as an aqueous pigment ink composition for ballpoint pens.

The physical properties of Examples 1 to 7 are shown in Table 2 below.

[0021]

[Table 2]

[0022] Next, as a comparative example, a composition having the composition shown in Table 3 below was prepared.

[0023]

[Table 3]

Comparative Example 1 is an ink composition prepared from Example 1 except that sodium polyoxyethylene oleyl ether phosphate was omitted. Comparative Example 2 is an ink composition prepared by removing ammonium oleate from the composition of Example 2. In Comparative Example 3, the amount of the nonionic fluorine-containing surfactant was increased so that 25 dyn /
The ink composition has a surface tension value smaller than 1 cm.
Comparative Example 4 is an ink composition prepared from Example 4 by removing ammonium oleate and sodium polyoxyethylene oleyl ether phosphate. Comparative Example 5 is an ink composition prepared from Example 2 by removing the nonionic fluorine-containing surfactant.

The physical properties of Comparative Examples 1 to 5 are shown in Table 4 below.

[0026]

[Table 4]

The pigment ink compositions for water-based ballpoint pens prepared as Examples 1 to 7 and Comparative Examples 1 to 5 were treated with an inner diameter of 3.5.
Approximately 10c in height in a polyethylene pipe
m, about 0.8 g in weight, filled with a stainless steel tip for water-based ballpoint pen, and filled with grease in the back of the ink to prevent drying and outflow of the ink. A test core used for the following test was obtained by removing air remaining between the inks.

Writing Feeling: The writing feeling when five testers handwritten the test core was evaluated. The evaluation was as follows: ◎: 4 or more out of 5 persons had good writing feeling. : Three out of five persons felt that the writing feeling was good. Δ: One or two of the five persons had good writing feel. X: One out of five persons did not consider that the writing feeling was good. In four stages.

Bleedability: Written by hand on a writing paper, and the evaluation was made based on the line width of the image and the presence or absence of bleed at that time. The evaluation was as follows: ◎: No bleeding was observed. : Somewhat blurred but not noticeable. ×: Bleeding is observed and the line width is increased. In three stages.

Long-term stability: A test core was placed in a glass container and stored in a thermostatic chamber set at a temperature of 50 ° C. and a relative humidity of 60%. After 6 months, the viscosity and pH value of the ink composition were measured. Measured and watched the change. The evaluation was as follows: ◎: A change in viscosity was within ± 20%, and a change in pH value was negligible or very slight. ：: The change in viscosity is ± 20 to 50% and the change in pH value is less than 1. X: The change in viscosity is ± 50% or more, or the ink gels or separates, or the change in pH value is 1 or more. In three stages.

Lubricity: A test core was written at room temperature at a writing angle of 70 °, a writing speed of 4 m / min, and a writing load of 100 g, and the ink consumption was measured at a writing distance of 100 m. In addition, the degree of wear of the ball seat of the stainless steel tip for the water-based ballpoint pen attached to the test core was observed. The evaluation was as follows: ◎: The ball seat was not worn, and there was no large difference in the ink consumption value for each writing distance of 100 m. : The ink consumption increased as the ball seat was slightly worn and the writing distance was increased. Δ: Abrasion of the ball seat was large, the ink introduction hole was closed, and the ink consumption gradually decreased, and the writing line condition deteriorated. X: The ink consumption was remarkably reduced, and 80 mg / 100
What has become m. In four stages.

Leakage: The pen tip of the test core was fixed vertically downward, and it was observed whether the ink spontaneously leaked from the pen tip. The evaluation was as follows: ◎: No leakage occurred. : Slightly leaked but not so noticeable. ×: Leakage caused trouble in writing. In three stages.

Chip corrosion: The test core was heated at a temperature of 50 ° C.
The sample was stored in a thermostatic chamber set to a relative humidity of 60%, and after 6 months, the corrosion state in the chip was observed using a microscope.
The evaluation was as follows: A: No corrosion was observed. : The inside of the chip was slightly discolored due to corrosion. ×: Discoloration significantly due to corrosion. In three stages.

Table 5 shows the results of the above six tests.

[0035]

[Table 5]

[0036]

As described in detail above, the effect is as follows. In a pigment ink composition for an aqueous ballpoint pen containing a pigment, a water-soluble resin and a water-soluble solvent, a nonionic fluorine-containing surfactant and ammonium oleate are essential components. And polyoxyethylene alkyl ether phosphate, a synergistic lubricating effect that cannot be obtained by simply adding a nonionic fluorine-containing surfactant, ammonium oleate, or polyoxyethylene alkyl ether phosphate alone And the writing feel is extremely good. Further, the surface tension is 25 to 30 dyn / c.
m, the pH value of the ink composition is 7.5 to 9.0.
A pigment ink composition for water-based ballpoint pens that has excellent long-term stability, is free from ink bleeding, does not leak from the tip of the metal tip, and has the effect of suppressing corrosion of the metal tip by being adjusted to fall within the range of Things.

Claims (1)

[Claims] 1. An aqueous pigment ink composition for a ballpoint pen containing a pigment, a water-soluble resin and a water-soluble solvent, comprising a nonionic fluorine-containing surfactant, ammonium oleate and polyoxyethylene alkyl ether phosphate as essential components. Containing and having a surface tension of 25 to 30 dyn /
A pigment ink composition for an aqueous ball-point pen, wherein the pH value is adjusted to be 7.5 to 9.0.