JPH06100825A - Water-base ink composition for ball-point pen - Google Patents

Abstract

PURPOSE:To obtain the subject compsn. which has such an excellent lubricity as to reduce the abrasion of a ball holder, and is excellent in durability and feeling during writing. CONSTITUTION:The objective water-base ink compsn. contains a water-sol. dye or a water-dispersible pigment, a water-sol. org. solvent, water, and at least one urea deriv. represented by the general formula: R1HNCONHR2 (wherein R1 and R2 are each 1-6C alkyl or 3-6C cycloalkyl).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aqueous ink composition for ballpoint pens. More specifically, the present invention relates to a water-based ink composition for a ball-point pen, which exhibits excellent lubricity, suppresses abrasion between the ball receiving seat and the ball of the ball-point pen tip, and makes ink flow out smoothly.

[0002]

2. Description of the Related Art Conventionally, water-based ink compositions for ballpoint pens have been formed by adding a water-soluble organic solvent such as a polyhydric alcohol or its derivative to an aqueous solution containing a water-soluble dye or a water-dispersible pigment. However, such a water-based ink composition for a ballpoint pen has poor lubricity, and the distance between the ball and the holder increases due to the rotation of the ball during writing, which causes rattling of the ball and poor rotation of the ball, resulting in poor writing quality. There is a drawback that so-called line skipping occurs in which parts of the handwriting are blurred.

[0003]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a water-based ink composition for ball-point pens that overcomes the drawbacks of conventional water-based ball-point pens and has excellent lubricity and little bleeding and is stable over time. That is.

[0004]

As a result of intensive studies to solve these drawbacks, the present inventor has found that a water-based ink composition for ball-point pens comprising a water-soluble dye or water-dispersible pigment, a water-soluble organic solvent, and water. The above-mentioned problems have been solved by providing an aqueous ink composition for a ballpoint pen, characterized in that it contains at least one compound represented by the following general formula. [General Formula] R ₁ HNCONHR ₂ (R ₁ and R ₂ are C _{1 ■ 6} Alkyl Group or C _{3 ■ 6} Cycloalkyl Group)

The present invention will be described in detail below. The compound represented by the above general formula is added as a lubricant, and specific examples thereof include 1,3-dimethylurea, 1,3-diethylurea, and N, N′-dicyclohexylurea.
The amount used can be from 0.1 to 20% by weight, and preferably from 0.5 to 5% by weight, based on the total amount of the ink composition. If the amount used is small, a sufficient lubricating effect cannot be obtained, and if the amount used is large, the stability over time deteriorates.

The water-soluble dye contained in the water-based ink composition for a ballpoint pen of the present invention may be one used in ordinary water-based inks, such as C.I. I. Acid Red 87, C.I. I. Acid Orange 56, C.I. I. Acids By Ole 4
9, C.I. I. Acid dyes such as Acid Blue 9, C.I. I.
Direct Yellow 50, C.I. I. Direct black 1
Direct dyes such as C.9. I. Basic Blue 9, C.I.
I. Basit clad 1, C.I. I. Basic dyes such as Basic Yellow 35 can be used, and they may be used alone or in combination of two or more kinds. As the pigment, various known pigments can be used, and specific examples include azo pigments, condensed polyazo pigments, phthalocyanine pigments,
Organic pigments such as quinacridone pigments, anthraquinone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, perinone and perylene pigments, titanium oxide,
Inorganic pigments such as iron oxide and carbon black, and fluorescent pigments may be used, and these may be used alone or in combination of two or more kinds. The colorant may be used in an amount of 0.1 to 30% by weight, preferably 1 to 20% by weight, based on the total ink composition. If the amount used is small, the handwriting becomes thin, and if the amount used is large, the viscosity of the ink composition increases and the writing quality becomes poor.

As the dispersant, those generally used as pigment dispersants such as resins and surfactants can be used, and the amount thereof is preferably 1 to 20% by weight based on the total amount of the ink.

Examples of the water-soluble organic solvent include polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin, glycol ethers such as propylene glycol monomethyl ether and glycol ether acetates such as propylene glycol monomethyl ether acetate. These may be used alone or in combination of two or more. The content of these water-soluble organic solvents is preferably 1 to 40% by weight based on the total amount of the ink. If the amount used is small, the pen tip will dry quickly, and if the writing line is blurred, if it is large, the handwriting will dry slowly.

In addition, if necessary, pseudoplasticity-imparting agents, rust preventives, surfactants, antiseptic / antifungal agents and the like can be appropriately selected and used. As the pseudoplasticity-imparting agent, natural polysaccharides and semi-synthetic cellulosic polymers can be used among general water-soluble polymers. More specifically, as a natural polysaccharide,
It is possible to use guar gum, locust bean gum, welan gum, rhamsan gum, xanthan gum and the like having a high molecular chemical structure composed of monosaccharides such as glucose, galactose, rhamnose, mannose and glucuronate. Further, as the semi-synthetic cellulose-based polymer,
It is possible to use methyl cellulose, ethyl cellulose, carboxymethyl cellulose, etc., which are water-soluble by esterifying or etherifying the hydroxyl groups of cellulose. Benzotriazole can be used as the rust preventive. As the preservative, phenol, potassium sorbate, sodium benzoate or the like can be used. As the mildew-proofing agent, 1,2-benzisothiazolin-3-one can be used.

[0010]

Although it is not clear why the water-based ink composition for a ballpoint pen of the present invention is effective in preventing abrasion of the ball receiving portion, it is presumed as follows. That is, it is considered that the compound represented by the following general formula is adsorbed on the surface of the ball or the ball seat to form a thin film, and the lubricity of ball rotation is improved. [General Formula] R ₁ HNCONHR ₂ (R ₁ and R ₂ are C _{1 ■ 6} Alkyl Group or C _{3 ■ 6} Cycloalkyl Group)

[0011]

EXAMPLES The present invention will be described in more detail with reference to examples. In the following, "part" means "% by weight". Example 1 Eosin (C.I. Agitudred 87) 6.0 parts Propylene glycol 25.0 parts Neugen P (Daiichi Kogyo Seiyaku Co., Ltd., nonionic activator) 0.5 parts Sodium benzoate (preservative) 1. 0 part Proxel XL-2 (ICCI Japan Co., Ltd., antifungal agent) 0.5 part 1,3-Dimethylurea 20.0 parts Benzotriazole (rust inhibitor) 0.5 part Water 46. 5 parts The above components were heated to 50 to 60 ° C., stirred for 2 hours, cooled, and then filtered to obtain a red ink. Example 2 Water black R455 (CI Acid Black 2) 8.0 parts Ethylene glycol 20.0 parts Sodium benzoate (preservative) 1.0 part Proxel XL-2 (ICCI YAPAN Corporation) , Mildewproofing agent) 0.5 part Benzotriazole (rust inhibitor) 0.5 part Kerzan (manufactured by Sansei Co., Ltd., xanthan gum, pseudoplasticity imparting agent) 0.5 part 1,3-diethylurea 5.0 part Water 64.5 parts Of the above components, first, Kerzan was added to water little by little so that it could not be stiffened, completely dissolved by stirring, and the remaining components were stirred and dissolved, and then filtered to obtain a black ink. Example 3 Copper phthalocyanine blue 10.0 parts Sodium salt of styrene-maleic acid copolymer (dispersant) 2.0 parts Ethylene glycol 15.0 parts Diethylene glycol 5.0 parts Sodium benzoate (preservative) 1.0 parts Proxel XL-2 (ICCI Japan Co., Ltd., fungicide) 0.5 part Benzotriazole (rust inhibitor) 0.5 part Ramzan gum (Daiichi Kogyo Seiyaku Co., Ltd., pseudoplasticizer) 0.3 parts N, N'-dicyclohexylurea 1.5 parts Water 64.2 parts Copper phthalocyanine blue, a sodium salt of a styrene-maleic acid copolymer and 30 parts of water were dispersed in a sand mill for 1 hour. After that, each of the remaining components other than rumzan gum was mixed with 34.2 parts of water, and rumzan gum was added little by little so that Mamako could not be stirred, and a liquid that was dissolved by stirring was added,
After stirring for 1 hour, a blue ink was obtained by filtration.

Comparative Example 1 A red ink was obtained in the same manner as in Example 1, except that 1,3-dimethylurea in the ink component was replaced with the same amount of water. Comparative Example 2 A black ink was obtained in the same manner as in Example 2, except that 1,3-diethylurea in the ink component was replaced with the same amount of water. Comparative Example 3 A black ink was obtained in the same manner as in Example 3, except that N, N′-dicyclohexylurea in the ink component was replaced with the same amount of water.

[0013]

[Effect] The water-based ink compositions obtained in Example 1 and Comparative Example 1 have a diameter of 0.6 mm and a built-in ink absorber and relay core.
Of a so-called center-type writing instrument that fills an aqueous ball-point pen equipped with a super hard ball and a nickel-white ball-point pen socket to form a pen body, and the water-based ink compositions obtained in Examples 2 and 3 and Comparative Examples 2 and 3. With a so-called free-ink writing instrument obtained by pressing a ballpoint pen tip into one end of a polypropylene tube and centrifuging to remove the bubbles, confirm the effect using a spiral writing tester. went. The conditions of the tester at that time were a writing angle of 65 degrees, a load of 100 g, and a speed of 7 cm / sec, and the test paper was JIS P3201 Writing paper A. Under these conditions, the ball sinking after 500 m writing was measured using a tool microscope. . In addition, a handwriting sensory test was performed by handwriting. The results are shown in Table 1.

[Table 1] Evaluation standard for writing feeling Smooth ─── Writing smoothly. Squeak ─── There is resistance and I cannot write smoothly. As described above, the water-based ink composition for a ballpoint pen according to the present invention has excellent lubricity, has an effect of reducing abrasion of the ball receiving seat, and has excellent durability and writing feeling.

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[Procedure amendment]

[Submission date] August 31, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

As a result of intensive studies to solve these drawbacks, the present inventor has found that a water-based ink composition for ball-point pens comprising a water-soluble dye or water-dispersible pigment, a water-soluble organic solvent, and water. The above-mentioned problems have been solved by providing an aqueous ink composition for a ballpoint pen, characterized in that it contains at least one compound represented by the following general formula. [General Formula] R ₁ HNCONHR ₂ (R ₁ and R ₂ are C _{1 to} C ₆ Alkyl Group or C _{3 to} C ₆
Cycloalkyl group)

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010]

Although it is not clear why the water-based ink composition for a ballpoint pen of the present invention is effective in preventing abrasion of the ball receiving portion, it is presumed as follows. That is, it is considered that the compound represented by the following general formula is adsorbed on the surface of the ball or the ball seat to form a thin film, and the lubricity of ball rotation is improved. [General Formula] R ₁ HNCONHR ₂ (R ₁ and R ₂ are C _{1 to} C ₆ Alkyl Group or C _{3 to} C ₆
Cycloalkyl group)

Claims (1)

[Claims] 1. A water-based ink composition for a ballpoint pen containing a water-soluble dye or a water-dispersible pigment, a water-soluble organic solvent and water containing at least one urea derivative represented by the following general formula. A water-based ink composition for a ballpoint pen, which is characterized in that [General Formula] R ₁ HNCONHR ₂ (R ₁ and R ₂ are C _{1 ■ 6} Alkyl Group or C _{3 ■ 6} Cycloalkyl Group)