JP2002363473A - Aqueous ink composition and aqueous ball-point pen using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous ink composition and to provide an aqueous ball-point pen causing no blurring nor discontinued lines due to the corrosion of a penpoint even after a long preservation without using an aqueous ink composition containing a rust-preventive agent. SOLUTION: The aqueous ink composition has an electrical conductivity of <=1.5 mS/cm. The ball-point pen having the ball made of a hard metal uses the aqueous ink composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ink composition having improved corrosion resistance of a metal ball such as a cemented carbide at a pen tip portion, and an aqueous ballpoint pen provided with the same.

[0002]

2. Description of the Related Art Generally, ball-point pens include a direct liquid type in which ink is directly stored in an ink storage tube and a batting type in which an ink occluding material such as a fiber bundle is used. A writing ball is rotatably held by a socket at the tip of the pen tip. The above-mentioned nib tip portion requires a certain degree of hardness for performance such as sufficiently withstanding the pressure at the time of writing depending on the manner of use of the ballpoint pen. As a material, a metal material such as nickel silver or stainless steel is usually used.

[0003] In recent years, water-based ballpoint pens have gained attention because of their widespread use as writing implements due to the practical use of ballpoint pens having various characteristics such as brilliant coloring.
Conventionally, there has been a problem that the ink flows out when the ink is stored vertically downward, and the ink flows back inside the aqueous ballpoint pen when the ink is stored vertically upward. As a solution to this problem by a ballpoint pen mechanism, a spring is provided in the tip of the pen tip, and the spring constantly prevents ink from flowing out when stored vertically downward by means for applying pressure to the ball. The backflow of the ink inside the ballpoint pen when stored vertically upward is achieved by means including a ball which is a valve body for backflow prevention at the rear part in the tip part.

[0004]

However, when a water-based ballpoint pen is stored for a long period of time, metal parts such as the ball and socket of the pen tip tip corrode because the ink contains moisture, and the ball is not recharged. When a cemented carbide is used as the metal material, the periodic table IVa, Va,
Due to corrosion such as elution of a binding metal such as Co used to form the powder of the carbide of the Group VIa metal into a spherical shape, there is a problem that writing is reduced and the writeability is reduced.

[0005] In order to solve this problem, it is usual to use an ink composition using various rust inhibitors as an ink composition for an aqueous ballpoint pen. However, rust preventives are generally poorly soluble in water, such as benzotriazole, easily gelled, such as metal salts, or difficult to manufacture. Since the aqueous ink composition using such a rust inhibitor is a special aqueous ink composition, an ink for an aqueous ballpoint pen that does not require the use of a rust inhibitor is desirable.

[0006]

The inventors of the present invention have made intensive studies and found that the electrical conductivity of the ink was 1.5 mS / cm.
By providing the following water-based ink composition in a ballpoint pen, without using a special water-based ink composition using a rust inhibitor, found that rust does not occur even during long-term storage, the present invention Reached.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to an aqueous ink composition having an electric conductivity of 1.5 mS / cm or less, and an aqueous ballpoint pen provided with the aqueous ink composition.

[0008] The aqueous ink composition of the present invention only needs to have an electrical conductivity of 1.5 mS / cm or less as a final aqueous ink. When the electric conductivity of the ink provided on the ballpoint pen is greater than 1.5 mS / cm, the ball provided at the tip of the pen tip includes a metal on at least the surface and a metal other than the ball includes the metal on at least the surface If the surface metal of the component is different, electrolysis proceeds because current flows between the metal contained in the surface of the ball and the metal contained in the surface of the component. If C
Undesirably, the binding metal such as o elutes, causing corrosion of the ball and lowering the writability.

The composition of the aqueous ink composition is not particularly limited, and any raw material may be used or combined as long as the electric conductivity of the ink is 1.5 mS / cm or less. However, for example, a viscosity modifier, a coloring agent, a water-soluble organic solvent, and other various additives can be used as needed. In addition, it is preferable that the water-based ink composition does not substantially contain a substance having a rust-preventing effect such as a rust-preventive agent from the viewpoint of easiness of a manufacturing process typified by availability.

As the viscosity modifier that can be used in the aqueous ink composition, natural polymers and synthetic polymers can be used, and polysaccharides (such as natural polysaccharides) and semi-synthetic cellulose-based polymers can be used. And a water-soluble synthetic polymer can be suitably used. The viscosity modifiers can be used alone or in combination of two or more.

The polysaccharide is not particularly limited as long as the viscosity of the ink can be adjusted, but it is preferable to use a polysaccharide that gives thixotropy.
Galactose, rhamnose, mannose, and macromolecules having a macromolecular chemical structure composed of monosaccharides such as glucuronate, and the like, and microbial polysaccharides or derivatives thereof,
Water-soluble plant polysaccharides or derivatives thereof, water-soluble animal polysaccharides or derivatives thereof, and the like can be used. As polysaccharides,
Specifically, pullulan, xanthan gum, welan gum, ramzan gum, microbial polysaccharides such as succinoglucan or derivatives thereof, guar gum, locust bean gum, trigant gum, tarara gum, karaya gum, gati gum, arabinogalactan Water-soluble plant polysaccharides such as gum, quince seed gum, silium seed gum, gum arabic, pectin, starch and the like, and derivatives thereof, and water-soluble animal polysaccharides such as gelatin and casein or a derivative thereof, and the like.

The semi-synthetic cellulose-based polymer includes, for example, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl ethyl cellulose, carboxymethyl cellulose or a salt thereof ( Sodium salt). Examples of the synthetic polymer include polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acid, and methyl vinyl ether maleic anhydride copolymer.

The colorant that can be used in the present invention may be any as long as it can impart coloring properties to the ink.
Those having solubility and dispersibility are preferred. Specifically, in addition to water-soluble dyes such as acid dyes, direct dyes, and basic dyes, inorganic pigments such as carbon black and titanium oxide, copper phthalocyanine pigments, sulene pigments, azo pigments, quinacridone pigments, anthra Quinone pigments, dioxane pigments, indigo pigments, thioindigo pigments,
In addition to organic pigments such as perinone pigments, perylene pigments, indolenone pigments, and azomethine pigments, glass flake pigments, metal powder pigments such as aluminum powder, pearl pigments, fluorescent pigments, colored resin emulsions, alkylene bismelamine derivatives, Plastic pigments (synthetic resin particle pigments) of various shapes such as spherical and flat, etc.
These can be used as a pigment dispersion. Also,
The coloring agents can be used alone or in combination of two or more.

The water-soluble organic solvent that can be used in the aqueous ink composition is not particularly limited as long as it can prevent drying or freezing at low temperatures by using the aqueous ink composition. But not ethylene glycol, diethylene glycol,
Glycols such as propylene glycol,
They can be used alone or in combination of two or more.

Examples of various additives that can be used as needed in the aqueous ink composition include, for example, polyoxyethylene alkali metal salts, dicarboxylic acid amides, and the like.
Lubricants such as phosphate esters and N-oleyl sarcosine salts, and preservatives and fungicides such as benzoisothiazoline, pentachlorophenol and cresol can be used.

[0016] The ballpoint pen of the present invention comprises the above-mentioned aqueous ink composition, comprises a ball containing metal on at least the surface of the pen tip, and further comprises a part other than the ball, wherein the part contains metal on at least the surface. It is also provided.

The ball provided on the pen tip portion of the ballpoint pen according to the present invention is not particularly limited as long as it includes metal on at least the surface. Even if the ball is entirely made of metal, Alternatively, the entire surface of a sphere made of a material other than metal may be coated with a material containing metal, but it is preferable that the ball is made of a cemented carbide for wear resistance. The metal contained in the surface of the ball is not particularly limited, and may be, for example, stainless steel.When the ball is a cemented carbide, the bonding metals cobalt, chromium, titanium, and vanadium are used. It may be.

The component other than the ball provided in the ballpoint pen of the present invention is not particularly limited, but is a component that is in contact with or immersed in the ink in which the ball is in contact or immersed. At least a metal different from the metal contained in the surface portion of the ball is contained in the surface. If the ball and the component are not in contact with or immersed in the same aqueous ink composition, no current can flow between the metals. Also,
The metal contained in the surface portion of the ball and the metal contained in the surface of the component may have different types, composition ratios, and crystal orientations, but have a standard oxidation-reduction potential difference of 0.5 V or more. Is preferred.

The types of the components include, for example, a socket provided in the nib tip portion, a spring provided in the nib tip for applying pressure to the ball, a ball which is a valve body for preventing backflow, and a metal refill. Body.

The metal contained on the surface of the component may be
There is no particular limitation. For example, SUS304 stainless steel (nickel chrome alloy steel), SUS430 stainless steel (chromium alloy steel), brass, nickel silver, phosphor bronze alloy, free-cutting stainless steel, etc., alone or in combination of two or more It can be used in combination. Further, the alloy may be used after the surface coating component is peeled off, and the SUS304 stainless steel may be the one from which the nickel coated on the surface is peeled off. As stainless steel, it is easy to work because it has non-cutting properties comparable to free-cutting brass. Therefore, the trade name "DSR6F" (ferritic, manufactured by Daido Special Steel Co., Ltd.), which is a free-cutting stainless steel, is used. It can be suitably used.

In the ballpoint pen of the present invention, the combination of a ball provided on the pen tip portion with metal on at least the surface and a component other than the ball and having a metal on at least the surface is particularly limited. However, it is preferable that the ball is a cemented carbide ball and the component is a free-cutting stainless steel for wear resistance and impact resistance.

[0022]

EXAMPLES Examples and comparative examples of the present invention will be described below, but the present invention is not limited thereto.

(Production Example of Blue Pigment Dispersion) 25 parts by weight of a blue pigment (trade name "Fast Gen Blue TGR", manufactured by Dainippon Ink Industries, Ltd.), styrene-acrylic resin (trade name "John Krill 683", Johnson) (Polymer)
, 5 parts by weight of propylene glycol, 0.06 parts by weight of sodium hydroxide, and 64.9 parts of ion-exchanged water.
4 parts by weight of each was added and dispersed by a known bead mill to obtain a blue pigment dispersion having an average particle size of 0.12 μm.

According to the composition shown in Table 1, a blue pigment dispersion,
The components of the water-soluble organic solvent, water, and, if necessary, the aluminum powder pigment were mixed and stirred by a known method, and then a viscosity modifier and an antiseptic / antifungal agent were added thereto, followed by mixing and stirring. This was filtered and then defoamed. Examples 1-3 and Comparative Examples 1-3
Of aqueous ink compositions were obtained.

[0025]

[Table 1]

As the blue pigment dispersions in Table 1, those prepared in Production Examples were used, and the following various raw materials were used.

The aluminum powder pigment used was "Alpaste WXM0630" (manufactured by Johnson Polymer). Carboxymethylcellulose (trade name "Selogen 5A", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used as the viscosity modifier A, and ramzan gum (trade name "K7C23") was used as the viscosity modifier B.
3 ", manufactured by Sansei Co., Ltd.). As the antiseptic / antifungal agent, "Proxel XL-2" (trade name, manufactured by Zeneca Corporation) was used.

[Evaluation Test] Examples 1 to 3 and Comparative Examples 1 to
The electrical conductivity at a liquid temperature of 25 ° C. was measured for each of the ink compositions obtained in Step 3 by a known measuring method using an electric conductivity meter (electric conductivity meter model: CM-2A, manufactured by Toa Denpa Kogyo Co., Ltd.). It was measured. The ink compositions obtained from Examples 1 to 3 and Comparative Examples 1 to 3 were made of polypropylene, the material of the ink containing tube was stainless steel, the material of the socket portion of the ballpoint pen tip was stainless steel, and the material of the ball portion was super hard. Alloy (Sintered tungsten carbide,
The ball-point pen was housed in a ball-point pen having a configuration of bonding metal: Co, Cr) and assembled. After leaving each of the assembled ballpoint pens at room temperature for one year, the writing performance by handwriting and the corrosion of the ball portions were evaluated. Table 2 shows the results.

(Evaluation of Writability) Each of the assembled ball pens was allowed to stand at room temperature for one year, and then handwritten on a high-quality paper and evaluated according to the following criteria. 〇: I was able to write normally. ×: The writing line is faint and the writing is poor.

(Evaluation of Corrosion of Ball Part) Each of the assembled ball-point pens was left at room temperature for one year,
The surface condition of the ball portion was observed with a microscope and evaluated according to the following evaluation criteria. In the microscopic observation, KH2700 (trade name, manufactured by Hi-Rox Co., Ltd.) was used for the microscope, and the microscope was observed at a magnification of 250. 〇: No abnormality was observed in the ball portion. ×: Corrosion was observed in the ball portion.

[0031]

[Table 2]

(Summary of Evaluation) The water-based ballpoint pens using the water-based ink compositions of Examples 1 to 3 which are water-based ink compositions according to the present invention all have an electric conductivity of 1.5 mS / cm.
Below, the writability was good and no corrosion occurred on the surface of the ball. On the other hand, the aqueous ink compositions of Comparative Examples 1 to 3 not using a rust inhibitor had an electric conductivity of 1.5 m.
It was larger than S / cm, the writing property was poor, and corrosion occurred on the surface of the ball.

[0033]

According to the present invention, the electric conductivity of the present invention is 1.5 mS.
By using a water-based ink composition of not more than / cm and a ball-point pen provided with this water-based ink composition, the ball at the tip of the pen tip did not corrode even during long-term storage, and the writing performance was good.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C350 GA03 HA09 KD02 KD09 NA01 NA02 NA10 NA11 NC02 NC10 NE07 4J039 AB01 AB02 BA04 BA13 BC10 BC39 BE01 BE02 BE12 BE23 CA03 EA24 EA48 GA27

Claims (4)

[Claims] 1. The ink has an electric conductivity of 1.5 mS / cm.
An aqueous ink composition comprising: 2. The electric conductivity of the ink is 1.5 mS / cm.
An aqueous ballpoint pen comprising the following aqueous ink composition. 3. The ink has an electric conductivity of 1.5 mS / cm.
A ball-point pen provided with the following water-based ink composition, wherein (1) the ball-point pen includes a ball including a metal on at least the surface thereof in a pen-tip portion, and (2) the pen-point tip includes a metal on at least the surface. Equipped with a ball containing
(3) The water-based ball-point pen is characterized in that the ball-point pen is other than the ball and has a component containing a metal on at least the surface. 4. The water-based ballpoint pen according to claim 2, wherein the component is at least one selected from the group consisting of a backflow preventing ball, a spring, and a socket.