JP2000219839A - Pigment ink composition for aqueous ballpoint pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject pigment ink composition not making ink leakage from a pen point, even when a ballpoint pen is allowed to stand in a quiet condition, not generating a blot, even when used for writing at a high temperature, and having a stable writing performance not changed with the lapse of time, by compounding a specified polymeric compound. SOLUTION: This pigment ink composition is obtained by adding (E) a reversibly and heat-sensitively gelling polymeric compound having a gelation-starting temperature of 30-50 deg.C [for example, poly(N-isopropylethylacrylamide), poly(N- isopropylmethacrylamide), poly(N-cyclopropylacrylamide) and poly(N,N- diethylacrylamide)] in an amount of, preferably, 0.05-15 wt.%, more preferably, 0.1-10 wt.% to an aqueous ballpoint pen pigment ink composition containing (A) a pigment (an ordinary inorganic or organic pigment), (B) a pigment dispersing agent (for example, a polyacrylate-styrene copolymer), (C) a water-soluble solvent (for example, propylene glycol), and (D) a water-soluble polymeric resin (for example, tragacanth gum) as main components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ballpoint pen ink using a pigment as a colorant, and more particularly, to a pigment containing a pigment, a pigment dispersant, a water-soluble solvent and a water-soluble polymer resin as main components. The present invention relates to a pigment ink composition for an aqueous ballpoint pen.

[0002]

2. Description of the Related Art Water-based ballpoint pens have characteristics such as lighter writing feel, higher writing line density and less dents than oil-based ballpoint pens. It has become. Early aqueous ballpoint pens used fiber bundles and foams as ink reservoirs, which were filled with ink compositions containing dyes and water-soluble solvents as main components, but because dyes were used as colorants, Water resistance and light resistance are poor, and instead, an aqueous pigment ink composition using a pigment as a colorant has been proposed.

[0003] In the aqueous pigment ink composition, it is important to make the pigment used as a colorant into fine particles and to stably disperse the pigment so as to have excellent long-term stability. In order to obtain excellent long-term stability, a water-soluble polymer resin is used as an ink viscosity modifier. For example, tragacanth gum, guar gum, alginic acid, carrageenan, xanthan gum, dextrin, casein, methylcellulose, ethylcellulose, hydroxyethylcellulose,
Carboxymethylcellulose, N-vinylacetamide, polyvinylpyrrolidone, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, alkali metal salt of acrylic resin, copolymer of alkyl methacrylate, copolymer of vinyl acetate and polyvinylpyrrolidone And a mixture of two or more of such water-soluble polymer resins.

However, even when the above-mentioned resin is used, a so-called "tip leakage" occurs in which the ink composition does not hold in a stationary state and the ink leaks from the pen tip of a ball-point pen due to the properties of the resin used. Or where the temperature exceeds about 30 ° C., there is a problem in that the ink viscosity generally decreases, and the ink is liable to be burned during writing.

[0005] In order to solve the above-mentioned problems, for example, a cation-exchangeable synthetic silicate having a smectite structure is added (see JP-A-4-292672), and a cross-linked acrylic acid polymer is used (see JP-A-Hei. 6-57194), and a mixture of fine powdered silicon dioxide and alumina (see Japanese Patent Application Laid-Open No. 7-76665). However, the viscosity is reduced due to the presence of metal ions in the ink. However, problems such as poor properties and clogging of an inorganic substance to be added in a tip, which is a pen point, occur, and the problem has not been sufficiently solved.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to prevent ink from leaking from a pen tip even when a ballpoint pen is kept still.
It is an object of the present invention to provide a water-based ballpoint pen pigment ink composition which does not generate burrs even at the time of writing at a high temperature exceeding about 0 ° C. and has stable writing performance without a change over time.

[0007]

According to the present invention, as a result of various studies to solve the above-mentioned problems, a reversible thermosensitive gel polymer compound having a gelation start temperature of 30 to 50 ° C., for example, Poly N-isopropylethyl acrylamide (gelation start temperature (the same applies hereinafter) 31 ° C.), poly N-isopropyl methacrylamide (44 ° C.), poly N-cyclopropyl acrylamide (46 ° C.), poly N, N-diethyl acrylamide (32 It has been found that the object can be achieved by adding (C.) to the pigment ink composition for aqueous ballpoint pens, and the present invention has been completed.

The term “reversible thermosensitive gel polymer compound” as used herein means a compound whose solution viscosity reversibly increases at a certain temperature or higher. The aqueous solution containing this reversible thermosensitive gel polymer compound shows a reversible viscosity change in which the viscosity of the aqueous solution increases at a certain temperature or higher and the viscosity of the aqueous solution decreases at a certain temperature or lower. . This phenomenon is
This is due to the sol-gel transition occurring in the aqueous solution. In other words, this is because the reversible thermosensitive gel polymer compound undergoes a discontinuous volume change (phase transition) from the swelling phase to the shrinking phase depending on the temperature. It is thought to be due to changes in movement.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The reversible thermosensitive gel polymer compound used in the present invention has a viscosity of 30.
It is preferable that gelation occurs in the range of ５０50 ° C., and by using this, it is possible to efficiently suppress a decrease in viscosity caused by a rise in temperature. As the reversible thermosensitive gel polymer compound used, poly-N-isopropylethylacrylamide (gelation onset temperature (hereinafter the same))
31 ° C.), poly N-isopropyl methacrylamide (4
4 ° C.), poly N-cyclopropylacrylamide (46
° C), poly N, N-diethylacrylamide (32 ° C)
And the amount of addition is 0.05 to 15% by weight, preferably 0.1 to 10% by weight based on the total amount of the ink composition.
It is preferable to set the range as a guide. If the content of this reversible thermosensitive gel polymer compound is too small, the viscosity adjusting function is not exhibited, and if the content is too large, the viscosity adjusting function is exhibited too much, resulting in high viscosity and ink inside the pen tip and chip. As a result, the flow rate is obstructed, resulting in poor writing.

[0010] The pigment used in the present invention is not particularly limited, and any pigment can be used from general inorganic and organic pigments used in vice general pigment aqueous ballpoint pen inks. Alternatively, a pseudo pigment obtained by emulsion polymerization may be used. As the pseudo pigment, there is a dye obtained by dyeing an acrylic resin latex with a fluorescent dye. The type of the pseudo pigment is not particularly limited as long as it can be dispersed well in water. Specific examples include carbon blacks such as fanest black, contact black, acetylene black, and thermal black, black iron oxide, yellow iron oxide, red iron oxide, ultramarine, navy blue, cobalt blue, inorganic pigments such as titanium yellow, and C. . I. Pigment Black 7, C.I.
I. Pigment Blue 15, 16, 17, 22,
C. I. Pigment Red 5, 22, 22, and 4
1, same 49, same 88, same 112, same 122, same 146,
170, 190, 206, 245, 258,
C. I. Pigment Orange 5, 10, 13, 13
6, 40 and 43, C.I. I. Pigment Violet 19, 23, 31, 36, 50, C.I. I. Pigment Brown 25 and 26, C.I. I. Pigment Yellow 3, 12, 13, 24, 81, 95, 97, 108, 110, 120, 139, 1
66, C.I. I. Pigment Green 7, 10, 10
6, and the like. As a pseudo pigment,
NKW series dispersion liquid manufactured by Nippon Fluorescent Chemical Co., Ltd.
There are Nile Color Series dispersions manufactured by Okunikoshi Co., Ltd. The amount of the pigment used in the present invention is selected in the range of 3 to 30% by weight, preferably 5 to 20% by weight, based on the total weight of the ink composition, as pigment% by weight.

As the pigment dispersant, an acryl / styrene copolymer, a maleic acid / styrene copolymer, and a neutralized salt thereof can be used.

The water-soluble solvents include propylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,3
-One or more of butylene glycol, thiodiethylene glycol, glycerin, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether and the like can be used, and usually 10 to 40% by weight.
Used in the range.

Examples of the water-soluble polymer resin include tragacanth gum, guar gum, alginic acid, carrageenan, xanthan gum, dextrin, casein, methylcellulose, ethylcellulose, hydroxyethylcellulose,
Carboxymethylcellulose, N-vinylacetamide, polyvinylpyrrolidone, sodium polyacrylate, carboxyvinyl polymer, polyethylene oxide, alkali metal salt of acrylic resin, copolymer of alkyl methacrylate, copolymer of vinyl acetate and polyvinylpyrrolidone These water-soluble polymer resins can be used alone or as a mixture of two or more, and are used in the range of 0.1 to 0.4% by weight based on the total amount of the ink composition.

It goes without saying that, besides the above-mentioned main components, generally used rust inhibitors, lubricants, surfactants, preservatives, wetting agents and the like can also be added. As rust inhibitors, benzotriazole, tolylazole,
Examples thereof include dicyclohexylammonium nitrate. As the lubricant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, or a fluorine surfactant can be selected according to the effect. Preservatives include sodium benzoate, potassium sorbate, sodium pentachlorophenol, sodium dehydroacetate,
-Benzoisothiazolin-3-one and the like. As the wetting agent, a hygroscopic substance such as urea or a urea derivative, an organic acid such as malonic acid or a derivative thereof, or a water-soluble polymer such as polyethylene glycol can be used.

However, depending on the additive used, there is a substance that changes the gelation start temperature (phase transition temperature) of the reversible thermosensitive gel polymer compound. Therefore, when using it, it is necessary to pay attention to the amount of addition. is there. For example, urea and urea derivatives, which are commonly used as lubricants, form hydrogen bonds with gels or water, weakening the hydrogen bonds between the gel networks, and further destroying the structure of water, resulting in phase transition. Increase the temperature. Examples of those which lower the phase transition temperature include sodium salts of organic acids, for example, sodium 4-hydroxybenzoate and disodium maleate, inorganic sodium chloride, magnesium chloride and the like.

[0016]

Examples and Comparative Examples Next, the present invention will be specifically described with reference to Examples and Comparative Examples. Examples and comparative examples of the pigment ink compositions for aqueous ballpoint pens of the present invention were prepared as shown in Table 1 below.

[0017]

[Table 1]

The method of preparing the pigment ink compositions for aqueous ballpoint pens of Examples 1 to 4 and Comparative Examples 1 to 3 shown in Table 1 will be described.

Examples 1 and 2 In a water-soluble solvent such as ethylene glycol, diethylene glycol, glycerin and the like and water, a small amount of an N-vinylacetamide resin and a copolymer resin of an alkyl methacrylate were added under vigorous stirring. To disperse and dissolve completely. Next, a pigment and an acrylic-styrene copolymer as a pigment dispersant are added, and after the pigment is uniformly dispersed, a small amount of additives such as a surfactant is added and stirred, and finally, a reversible thermosensitive gel is added. The molecular compound was added, and the mixture was stirred for 5 hours and then filtered to obtain an aqueous pigment ink composition for a ballpoint pen.

Examples 3 and 4 In water-soluble solvents of triethylene glycol and glycerin,
The N-vinylacetamide resin is added little by little to the water-soluble solvent with vigorous stirring to completely disperse and dissolve. Next, a pseudo-pigment is added and uniformly dispersed, then a surfactant is added and stirred. Finally, a reversible thermosensitive gel polymer compound is added, and the mixture is stirred for 5 hours and filtered. This was a pigment ink composition.

Comparative Example 1 The same treatment as in Example 1 was performed without using the poly-N-isopropylethylacrylamide in the composition of the aqueous ballpoint pen ink composition of Example 1 and increasing the amount of water instead. The water-based pigment ink composition for ball-point pens of Comparative Example 1 was used.

Comparative Example 2 The same treatment as in Example 2 was carried out except that carboxymethylcellulose was added in place of polyN-cyclopropylacrylamide in the composition of the pigment ink composition for aqueous ballpoint pens of Example 2. Thus, a water-based pigment ink composition for ball-point pens of Comparative Example 2 was obtained.

Comparative Example 3 The poly-N, N-diethylacrylamide used in the composition of the pigment ink composition for aqueous ball-point pens of Example 3 was not used.
Instead, the amount of the pseudo pigment was increased and the same treatment as in Example 3 was performed to obtain a pigment ink composition for an aqueous ball-point pen of Comparative Example 3.

The pigment ink compositions for aqueous ballpoint pens prepared as Examples 1 to 4 and Comparative Examples 1 to 3 were treated with an inner diameter of 3.5.
mm, a 110 mm long polyethylene pipe was filled, a stainless steel tip with a 0.5 mm ball diameter was attached to one end of the pipe, and the end of the filled ink was filled with grease for preventing ink drying and outflow. A test core used for the following test was obtained by removing air remaining between the chip and the ink by centrifugation.

Writing performance test: The test core was placed at 25 ° C. and 30 ° C.
Writing was performed at a temperature of 35 ° C. and 35 ° C., and burrs, dents, and cracks were observed. The evaluation was as follows: ：: Good writing lines were obtained with almost no blurring, dents and cracks. Δ: Scratches, dents, and cracks observed throughout the writing line. ×: A continuation of blurring, dents and broken characters that cannot be used as a writing instrument. In three stages.

Ink Leakage: Without the cap attached, the pen was left at room temperature with the pen tip facing down, and the state of ink leakage after 24 hours was observed.評 価: No change was observed in the tip of the pen. Δ: Rice grain size ink leakage was observed at the tip of the pen. ×: Ink leakage was observed such that ink dropped from the tip of the pen. In three stages.

Long-term stability: The pigment ink compositions for aqueous ball-point pens of Examples 1 to 4 and Comparative Examples 1 to 3 were placed in a glass container and placed in a thermostatic chamber set at a temperature of 50 ° C. and a relative humidity of 60%. After storing for a month and returning to room temperature, the viscosities of the ink compositions were measured. The evaluation was as follows: ：: Change in viscosity was extremely small. Δ: Change in viscosity is ± 30% or more, but can be used as a writing instrument. X: The change in viscosity is large and cannot be used as a writing instrument. In three stages.

Table 2 shows the results of the above three tests.

[0029]

[Table 2]

[0030]

As described in detail above, a reversible thermosensitive gel polymer having a gelation onset temperature of 30 to 50 ° C., for example, poly N-isopropylethylacrylamide (gelation onset temperature (hereinafter the same)) 31.degree. C.), poly N-isopropyl methacrylamide (44.degree. C.), poly N-cyclopropyl acrylamide (46.degree. C.), poly N, N-diethyl acrylamide (32.degree. C.), etc. are used in the pigment ink composition for aqueous ballpoint pens. This ensures that ink does not leak from the pen tip even when the ball-point pen is kept still, and that writing does not occur when writing at a high temperature exceeding 30 ° C. It is possible to provide a water-based pigment ink composition for a ballpoint pen having high performance.

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[Procedure amendment]

[Submission date] February 9, 1999 (1999.2.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

There is no particular limitation on the pigment used in the present invention, and any pigment can be used from general inorganic and organic pigments used in ordinary pigment-based ballpoint pen inks. Alternatively, a pseudo pigment obtained by emulsion polymerization may be used. As the pseudo pigment, there is a dye obtained by dyeing an acrylic resin latex with a fluorescent dye. The type of the pseudo pigment is not particularly limited as long as it can be dispersed well in water. Specific examples include carbon blacks such as fanest black, contact black, acetylene black, and thermal black, black iron oxide, yellow iron oxide, red iron oxide, ultramarine, navy blue, cobalt blue, inorganic pigments such as titanium yellow, and C. . I. Pigment Black 7, C.I.
I. Pigment Blue 15, 16, 17, 22,
C. I. Pigment Red 5, 22, 22, and 4
1, same 49, same 88, same 112, same 122, same 146,
170, 190, 206, 245, 258,
C. I. Pigment Orange 5, 10, 13, 13
6, 40 and 43, C.I. I. Pigment Violet 19, 23, 31, 36, 50, C.I. I. Pigment Brown 25 and 26, C.I. I. Pigment Yellow 3, 12, 13, 24, 81, 95, 97, 108, 110, 120, 139, 1
66, C.I. I. Pigment Green 7, 10, 10
6, and the like. As a pseudo pigment,
NKW series dispersion liquid manufactured by Nippon Fluorescent Chemical Co., Ltd.
There are Nile Color Series dispersions manufactured by Okunikoshi Co., Ltd. The amount of the pigment used in the present invention is selected in the range of 3 to 30% by weight, preferably 5 to 20% by weight, based on the total weight of the ink composition, as pigment% by weight.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

It goes without saying that, besides the above-mentioned main components, generally used rust inhibitors, lubricants, surfactants, preservatives, wetting agents and the like can also be added. Examples of the rust inhibitor include benzotriazole, Torirutori azole,
Examples thereof include dicyclohexylammonium nitrate. As the lubricant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, or a fluorine surfactant can be selected according to the effect. Preservatives include sodium benzoate, potassium sorbate, sodium pentachlorophenol, sodium dehydroacetate,
-Benzoisothiazolin-3-one and the like. As the wetting agent, a hygroscopic substance such as urea or a urea derivative, an organic acid such as malonic acid or a derivative thereof, or a water-soluble polymer such as polyethylene glycol can be used.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

However, depending on the additive used, there is a substance that changes the gelation start temperature (phase transition temperature) of the reversible thermosensitive gel polymer compound. Therefore, when using it, it is necessary to pay attention to the amount of addition. is there. For example, urea and urea derivatives, which are commonly used as lubricants, form hydrogen bonds with gels or water, weakening the hydrogen bonds between the gel networks, and further destroying the structure of water, resulting in phase transition. Increase the temperature. Examples of those which lower the phase transition temperature include sodium salts of organic acids such as sodium 4-hydroxybenzoate, disodium maleate, and inorganic salts.
There sodium chloride, magnesium chloride and the like.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

The pigment ink compositions for aqueous ballpoint pens prepared as Examples 1 to 4 and Comparative Examples 1 to 3 were treated with an inner diameter of 3.5.
mm, poly propylene Ren made pipe length 110 mm, filled respectively, equipped with a stainless steel tip with 0.5mm ball diameter at one end thereof, the ink end filled filled with grease ink drying and runoff prevention After that, remove the air remaining between the chip and the ink by centrifugation,
The test core was used for the following tests.

Claims (2)

[Claims] 1. An aqueous ballpoint pen pigment ink composition comprising a pigment, a pigment dispersant, a water-soluble solvent, and a water-soluble polymer resin as main components, the reversible temperature sensitivity having a gelation initiation temperature of 30 to 50 ° C. A pigment ink composition for an aqueous ballpoint pen, comprising a gel polymer compound. 2. The reversible thermosensitive gel polymer compound is poly-N
The pigment ink composition for aqueous ballpoint pens according to claim 1, which is -isopropylethylacrylamide, polyN-isopropylmethacrylamide, polyN-cyclopropylacrylamide, or polyN, N-diethylacrylamide.