JPH06145581A - Water-base ink composition for ball-point pen - Google Patents

Abstract

PURPOSE:To obtain the title compsn. which is a viscous neutral soln., hardly affected by the pH or salts, and has spinnability and lubricity by compounding a specific neutral polysaccharide and dimethylformamide or dimethyl sulfoxide into the compsn. CONSTITUTION:2-15 pts.wt. neutral polysaccharide and dimethylformamide and/or dimethyl sulfoxide are compounded into a water-base ink which at least contains a water-sol. or-dispersible colorant, a water-sol. org. solvent. and water. The polysaccharide has a structure regularly linked through alpha-1, 6 linkage contg. 3 molecules of glucose of a specific formula linked through alpha-1, 4 linkage. The obtd. compsn. is a viscous neutral soln., hardly affected by the pH or salts, has spinnability and lubricity, and hence is excellent in long stability, stability of ink flowing due to rolling of the ball during writing, and uniformity of written lines. Moreover, the compsn. is free from dripping during writing and gives quickly drying written lines.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ink composition for ballpoint pens. 2. Description of the Related Art A water-based ballpoint pen has characteristics that it is less viscous than an oil-based ballpoint pen and has a lighter writing feel, a stronger writing line, and no fluffing even after continuous writing. Therefore, its usage has expanded and it has come to be widely used for securities, office work, and multicolor drawing. Ink for water-based ballpoint pens should have appropriate viscosity and drainage,
There are no problems such as blurring, directionality, character breakage, Braille during writing, ink leakage during storage, and excellent initial writing performance. It must have properties such as good dryness of the handwriting, metal corrosion resistance to the tip metal tip, and excellent storage stability. Some aqueous ink compositions utilize gel-forming polymer substances such as polyvinyl alcohol and carrageenan. (JP-A-56-741
No. 64) [Problems to be Solved by the Invention] However, the ink composition is suitable for writing using capillarity by using batting of an aqueous marking pen, a writing pen, a felt pen and the like. However, they are not suitable for use in water-based ballpoint pens. That is, when this is used as a water-based ballpoint pen ink, ink leaks from the tip of the metal tip and the initial writing performance is poor. In addition, there is a problem in that, in continuous writing, the outflow of ink is non-uniform and directionality, blurring, etc. occur. [0006] As a result of considering the above-mentioned problems of the prior art, the present invention has identified a specific neutral polysaccharide and dimethylformamide, or one or two of dimethylsulfoxide. By adding and blending with water-based ink,
The present invention has been completed by finding that a composition which is remarkably excellent as an ink for a water-based ball-pen is obtained. That is, the present invention relates to the following aqueous ink composition for ballpoint pens. Three glucose molecules represented by the following general formula are α-
Ink composition for water-based ballpoint pens, characterized in that 2 to 15 parts by weight of 1,4-bonded and regularly α-1,6-bonded neutral polysaccharide and one or two of dimethylformamide or dimethylsulfoxide are contained. It is a thing. ## STR1 ## The neutral polysaccharide represented by the above general formula used in the present invention is well soluble in water to form a viscous neutral solution, which is hardly affected by PH and salts, and thus the string is drawn. And has lubricity. Therefore, by using this neutral polysaccharide, the ink composition can have an appropriate viscosity and an ink outflow property due to the rotation of the ball during writing. As the neutral polysaccharide, pullulan (manufactured by Hayashibara Co., Ltd.) is commercially available under the trade name, and this can be used. Dimethylformamide or dimethylsulfoxide is an organic solvent capable of dissolving the above-mentioned neutral polysaccharide, and is propylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, N-methyl-2, which are commonly used in aqueous ballpoint pens. -It is added and mixed as an associative amphiphilic solvent with an organic solvent such as pyrrolidone. If the above-mentioned generally used organic solvent is added and blended as a wetting agent without adding and blending dimethylformamide or dimethylsulfoxide, the ink lacks stability and causes a separation phenomenon with the passage of time. The amount of the neutral polysaccharide used is 2 to 15 in the ink composition.
It was 5 parts by weight, preferably 5-10 parts by weight. When the amount is less than 5 parts by weight, the ink viscosity is low, the spinnability is weak, and the ink easily leaks. On the other hand, when the amount is 10 parts by weight or more, the viscosity becomes high and the ink outflow tends to be obstructed. Is dimethylformamide or dimethylsulfoxide the same as the organic solvent used as a wetting agent,
The weight may be more than that. If the amount is less than the weight of the organic solvent used as a wetting agent, the ink may separate with the passage of time, resulting in poor stability. In the ink composition for a water-based ballpoint pen of the present invention, the neutral polysaccharide and dimethylformamide may be the same as the known water-based ballpoint pen ink, except for dimethylsulfoxide. That is, the ink composition of the present invention comprises 5 to 10 parts by weight of the above-mentioned neutral polysaccharide, 10 to 30 parts by weight of one or two kinds of dimethylformamide or dimethylsulfoxide, and 0.1 to 15 parts by weight of a water-soluble or water-dispersible colorant. Parts, surfactants, rust preventives, preservatives, dispersion stabilizers and other suitable additives in an amount of 0.05 to 10 parts by weight, a wetting agent of 5 to 30 parts by weight and / or the balance water. . Examples of the water-soluble or water-dispersible colorant include known water-soluble dyes and / or water-dispersible pigments, and one or more of those listed below can be used. If the amount used is too small, the color development is small and if the amount is too large, precipitation easily occurs in the case of pigments and dissolution becomes difficult in the case of dyes. As a water-soluble dye, CI Acid Red
18, Acid 87, CI Acid Orange 56, CI Acid Yellow 28, Acid Blue 7, Acid 9, CI Acid Violet 49, Acid Acid Dyes such as CI Acid Black 2, CI Direct Orange 6, CI Direct Yellow 44, 87, CI Direct Black 19, 71, 88
Direct dyes and the like can be exemplified. As the water-dispersible pigment, a dispersion-stable pigment treated with a polymer composed of a monomer containing both hydrophilic and hydrophobic groups in one molecule can be preferably used, and an inorganic pigment such as titanium oxide or carbon black. Examples include organic pigments such as Carmin 6B, CI Pigment Red 112, CI Pigment Blue 15, and CI Pigment Green 7. As the surfactant, a nonionic surfactant such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene alkyl ether, perfluoroalkylcarboxylic acid salt, perfluoroalkyl phosphate ester, and the like, Examples thereof include anionic surfactants such as formalin condensate of naphthalene sulphonate and perfluoroalkyl ethylene oxide adduct. As rust preventives, benzotriazole, tolyltriazole,
Examples thereof include dicyclohexyl ammonium nitrate. Examples of antiseptics include potassium sorbate, sodium benzoate, and sodium pentachlorophenol. Examples of the dispersion stabilizer include styrene acrylic resin, styrene maleic acid resin, acrylic methacrylic acid resin and the like. As the organic solvent of the wetting agent, one or more of the following are used. If the amount of the organic solvent used is too small, the decapping property is deteriorated. Organic solvents include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, 1.8-propanediol, 1.
Dihydric alcohols such as 3-butylene glycol, 1.4-butanediol, neopentyl glycol, hexylene glycol and thiodiglycol; polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, diglycerin and sorbit; ethylene glycol monomethyl Examples thereof include glycol ethers such as ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and diethylene glycol monobutyl ether; pyrrolidone; N-methyl-2pyrrolidone. The ink composition of the present invention is not limited to the above composition, and a composition containing components other than the above is also included in the scope of the present invention. For example, urea may be further added for the purpose of promoting the solubility of the dye and improving the decapping property. The ink composition of the present invention is produced, for example, as follows. While stirring at room temperature, the above-mentioned neutral polysaccharide was gradually added to a mixed system of water and one or two kinds of dimethylformamide or dimethylsulfoxide, and after completely dissolved, an organic solvent as a wetting agent, a coloring agent and a suitable agent. Add additives to dissolve or disperse uniformly. The present invention will be described in more detail with reference to the following examples and comparative examples. An ink composition was produced using each of the raw materials shown in Table 1, and the viscosity, the ink outflow property, the long-term stability, etc. were observed. The results are shown in Table 2. An ink composition was produced using each of the raw materials shown in Examples and Comparative Examples, and had a ball diameter of 0.7 mm, a superhard ball, a nib metal tip, and an ink lead hole made of nickel silver and having a diameter of 1.5 mm.
The ink tank is made of polypropylene and has an inner diameter of 4 mm and a length of 130 mm.
It was a ballpoint pen of the shape. [0012] ・ Viscosity: 25 ± 0.5 by ELD rotational viscometer
It was measured at ° C. Ink effluent property: Writing speed 400 cm / min Writing angle 70 ° Writing in load of 100 g under the condition of 100 g of writing load was measured. 100 to 150 mg is ○, 50 to 100 mg 150 to 200 m
g is Δ, and 50 mg or less or 200 mg or more is x.・ Long-term stability: Temperature 4 at the center of the ballpoint pen
Viscosity was measured after 3 months and 12 months of standing at 0 ° C. and humidity of 60%. If the increase / decrease in viscosity was within 10%, it was marked with "" within 10-15%, and with "" within 15%, it was marked with x.・ Ink leakage: At room temperature, the tip of the metal chip was faced down and left for a day and night. -Dryness of handwriting: After writing Arabic letters 1 to 5 on a high-quality paper, the time until it was dry to the touch was measured. If it is within 60 seconds, ∘60 to 90 seconds is Δ, and 90 seconds or more is ×. As is clear from Table 2, the ink composition of the present invention is
Stable ink outflow and long-term stability. Ink leak. The handwriting dryness was also good, and it was excellent as an aqueous ballpoint pen ink composition. When the neutral polysaccharide is used outside the range specified in the present invention, if it is too small as in Comparative Example 1, the ink leakage, ink leakage, and handwriting dryness are poor. Comparative example 2
If the amount is too large, the ink outflow is poor. In Comparative Example 1, when the proportions of ethylene glycol and glycol as a wetting agent were made higher than the proportions of dimethylformamide and dimethylsulfoxide, ink separation occurred and writing became impossible. In Comparative Example 3, the ink composition using polyvinyl alcohol in place of the neutral polysaccharide was poor in ink outflow property, long-term stability, ink leakage, and handwriting dryness. The ink composition of the present invention is characterized by containing a neutral polysaccharide and one or two of dimethylformamide or dimethylsulfoxide, and is a viscous neutral solution. Since it has the property of being less susceptible to the effects of PH and salts, and has spinnability and lubricity, it has excellent long-term stability of the ink, and the ink outflow due to ball rotation during writing is stable and uniform. It becomes a writing line. Furthermore, there is no flicker during writing. It has excellent advantages such as quick drying of handwriting.

Claims (1)

Claims: In an ink for a water-based ballpoint pen containing at least a water-soluble or water-dispersible colorant, a water-soluble organic solvent, and water, three glucose molecules represented by the following general formula:
Neutral polysaccharide 2 with 1,4 bond and regular α-1,6 bond 2
A water-based ink composition for a ballpoint pen, characterized by containing -15 parts by weight of dimethylformamide or one or two of dimethylsulfoxide. [Chemical 1]