JPH0150348B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a water-based ink for ballpoint pens, and more particularly to a water-based ink for ballpoint pens that has excellent lubricity and provides a smooth writing feel. [Conventional technology and its problems] Conventional water-based inks for ballpoint pens are made by adding dyes directly to an aqueous solution of water-soluble organic solvents such as glycol solvents, glycol ether solvents, glycol ether ester solvents, and amine solvents as evaporation inhibitors. These are low-viscosity water-based inks made by dissolving water-soluble dyes such as acidic dyes or basic dyes, and adding preservatives and anionic or nonionic surfactants as appropriate.
The problem is that the friction between the ball and the tip is large, causing abrasion noise between the ball and the tip when writing, and the writing feeling is not smooth, or there is wear on the synthetic resin or metal ball seat. This causes the problem that the clearance between the ball and the tip from which the ink is drawn is blocked, and the ink is not sufficiently drawn to the tip of the ball, resulting in blurred handwriting and difficulty in writing smoothly. Ta. In recent years, in order to solve these problems, attempts have been made to add water-soluble cutting oil to water-based ink, but satisfactory effects have not been obtained, and new problems have arisen, such as blurring of handwriting. [Means for Solving the Problems] The present inventors have completed the present invention as a result of intensive research to solve the above-mentioned problems. The gist of the invention is a water-based ink for ballpoint pens, which comprises at least a dye, a water-dispersible resin, a water-soluble polymer, a water-soluble organic solvent, and water. Next, each component used in the present invention will be explained in detail. Eiseneosin GH (C.
I.45380), Water Black #21 (CI15985,
42090, 42745 mixed dye), Nigrosine NB Conch (CI50420), Water Blue #9 (C.
I.42090), Water Pink #2 (CI45410), and Kayaktatrazine (CI19140).
I.35255), Kayak Water Black #9 (CI.
Direct Black #19), Direct Deep Black EX (CI35225), Direct Deep Black EA (manufactured by Sumitomo Chemical Co., Ltd.), Direct First Black Conc (CI27720), etc.
These can be used alone or in an appropriate mixture, and the amount used is preferably 2 to 30% by weight based on the total amount of the ink. Water-acidic resins form emulsions that are dispersed in ink, and specifically include polyacrylamides, N-methylolacrylamides, copolymers of acrylic acid and vinyl acetate, and acrylic acid and acrylic acid. These include copolymers with esters, copolymers with acrylic acid and vinyl chloride, copolymers with methacrylic acid and vinyl acetate, copolymers with methacrylic acid and acrylic esters, and these may be used alone or in combination. In particular, remarkable effects can be seen on polyacrylic acid, copolymers of acrylic acid and vinyl acetate, and copolymers of acrylic acid and acrylic esters. The amount used is 0.01 to 10% by weight, more preferably 0.1 to 5% by weight based on the total amount of the ink. If it is less than 0.01% by weight, the effect will be small, and if it is more than 10% by weight, problems such as precipitation and blurring of handwriting may occur. The water-soluble polymer exists dissolved in the ink. It is used to further stabilize the dispersion of water-soluble emulsion and to improve its lubricity.Specifically, it is used to stabilize the dispersion of water-soluble emulsion and to improve its lubricity.
Alginic acid, polyvinyl alcohol, polyvinylpyrrolidone, polyalkylene oxide, water-soluble epoxy compounds, etc. can be used alone or in combination, and the amount used is 0.01 to 10% by weight based on the total amount of ink, and more preferably ,
It is 0.1 to 5% by weight. If it is less than 0.01% by weight, the effect will be small, and if it is more than 10% by weight, problems such as precipitation and blurring of handwriting may occur. Examples of water-soluble organic solvents include glycol solvents, glycol ether solvents, glycol ether ester solvents, dimethylformamide, dimethyl sulfoxide, 2-pyrrolidone, N-methyl-
Examples include 2-pyrrolidone, which can be used alone or in combination, and the amount used is preferably 1 to 40% by weight based on the total amount of the ink. Further, the amount of water used as the main solvent is preferably 50 to 85% by weight based on the total amount of the ink. In addition to the above-mentioned components, penetrants such as various nonionic surfactants may be added in an amount of 5% by weight or less based on the total amount of the ink. Preservatives such as clophenol sodium, phenol, formalin, etc., and anti-catalysts such as benzotriazole, ethylenediaminetetraacetate, etc. are added as appropriate to prevent metal corrosion when metal is used in parts that come into contact with ink. You can also. Next, the method for manufacturing the ink of the present invention will be briefly described. The ink of the present invention can be produced by a simple operation of mixing and dissolving the above-mentioned components, but it is more preferable to first mix water and a water-soluble organic solvent, and then add a water-soluble emulsion of a water-soluble resin to the mixed solution. , After sufficient dispersion, other ingredients are added to obtain the ink. In addition, it is also possible to heat the mixture during stirring, if necessary. [Function] What is particularly important in the present invention is the combination of a water-dispersible resin and a water-soluble polymer. Although it is not clear whether this has the effect of preventing friction between the ball and the chip and preventing wear of the ball seat portion of the chip, it is speculated as follows. Water-dispersible resins have water-soluble groups and are hydrophobic, so they do not dissolve in water, and as a result, they form a hydrosol/emulsion state in water-based inks and are uniformly and stably dispersed. Due to its hydrophobic or oily nature,
It is thought to provide lubricity to the ink. or,
It is thought that by using a water-soluble polymer in combination, the dispersion of the water-dispersible resin is more stabilized, and the lubricity of the ink is further improved due to some kind of synergistic effect with the water-dispersible resin. [Examples] The present invention will be described in detail below based on Examples. In the examples, "parts" simply indicate "parts by weight." Example 1 Nigrosine NB Conc (CI50420, manufactured by Sumitomo Chemical Co., Ltd.) 6.5 parts Movinyl Powder SA (water-dispersible resin, manufactured by Hoechst Synthesis Co., Ltd.) 0.2 parts Solubilized starch (water-soluble polymer) 2.0 parts Penta Sodium chlorophenol (preservative)
0.5 parts Ethylene glycol 20.0 parts Water 70.8 parts Of the above ingredients, first mix water and ethylene glycol, heat to 40-50℃, add Movinyl Powder SA while stirring the mixture, and add it for 1 hour. After stirring, solubilized starch, then nigrosine
NB conc. and sodium pentachlorophenol were added in this order, and the mixture was further stirred for 1 hour while maintaining the liquid temperature at 40 to 50° C. to obtain a black ink. Comparative Example 1 A black ink was obtained in the same manner as in Example 1, except that Movinyl Powder SA and solubilized starch in Example 1 were removed and water was added in the same amount. Comparative Example 2 Except for Movinyl Powder SA of Example 1,
A black ink was obtained in the same manner as in Example 1 except that water was added in the same amount. Example 2 Water Blue #9 (CI42090, manufactured by Orient Chemical Industry Co., Ltd. 7.0 parts Jurimer AC-10N (water dispersible resin, manufactured by Nippon Pure Chemical Industries, Ltd.)
Co., Ltd.) 10.0 parts Polyvinyl alcohol (water-soluble polymer) 1.0 parts Sodium pentachlorophenol (preservative)
0.4 parts diethylene glycol 15.0 parts water 69.6 parts Of the above ingredients, first mix water and diethylene glycol, heat to 40-50°C, add Diyurimer AC-10N while stirring the mixture, and after stirring for 1 hour. , polyvinyl alcohol, Water Blue #9, and sodium pentachlorophenol were added in this order, and the mixture was stirred for 1 hour while maintaining the liquid temperature at 40 to 50°C to obtain a blue ink. Comparative Example 3 A blue ink was obtained in the same manner as in Example 2, except that the polyvinyl alcohol in Example 1 was removed and water was added in the same amount. Example 3 Kayaku Water Black #9 (CI Direct Black 29, manufactured by Nihon Kagaku Kogyo Co., Ltd.) 5.0 parts Julymar AT-515L (water-dispersible resin, manufactured by Nippon Pure Chemical Industries, Ltd.) 10.0 parts Metrose SM (water-soluble Polymer, Shin-Etsu Chemical
Co., Ltd.) 0.5 parts Proxel XL-2 (preservative, manufactured by Imperial Chemical Industries, Ltd.) 0.4 parts Ethyl carbitol 15.0 parts Water 69.1 parts Of the above ingredients, first mix water and ethyl carbitol, Heat the mixture to 50°C, add Julymer AT-515L while stirring the mixture, and after stirring for 1 hour, add Metrose SM, then Kayak Water Black #9, and Proxel XL-2 in this order, and bring the temperature of the mixture to A black ink was obtained by stirring for another 1 hour while maintaining the temperature at 40 to 50°C. Comparative Example 4 Same as Example 3, except for Jurimer AT-515L and Metrose SM, except that the same amount of water was added. A black ink was obtained in the same manner as in Example 3. [Effect] The inks obtained in Examples 1 to 3 and Comparative Examples 1 to 4 above were used in a commercially available metal tip ballpoint pen (tip material: brass, ball material: tungsten). Filled with carbide-containing steel, ball diameter: 0.6mm),
Table 1 shows test results regarding writing distance, amount of ball sinking after writing, and abrasion noise during writing.

【table】

【table】

[Table] As described above, when the ink of the present invention is used in a water-based ballpoint pen, it has excellent abrasion prevention effect and lubricity between the metal ball and the tip, and the tip is made of synthetic resin such as polycarbonate other than metal. This water-based ink for ballpoint pens has excellent abrasion resistance even when writing, and as a result, the writing distance for smooth writing is greatly extended, and the generation of unpleasant sounds due to abrasion during writing is minimized.

Claims (1)

[Scope of Claims] 1. A water-based ink for a ballpoint pen comprising at least an acid dye and/or a direct dye, a water-dispersible resin, a water-soluble polymer, a water-soluble organic solvent, and water. 2. The water-based ink for ballpoint pens according to claim 1, wherein the water-dispersible resin is polyacrylic acid, a copolymer of acrylic acid and vinyl acetate, or a copolymer of acrylic acid and acrylic ester.