JPS6221388B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-based ink with excellent drying resistance.

Traditionally, for example, writing instruments, specifically writing instruments with pen nibs made of fiber, felt, or monofilament,
Or, for capillary type writing instruments such as fountain pens, even if the pen tip is exposed to the atmosphere for a long time during storage or when the cap is removed from the writing instrument body, ink always flows smoothly without clogging the ink flow path of the pen tip. There was a need for a water-based ink that would flow and allow extremely smooth writing.

In order to meet these demands, glycol solvents such as ethylene glycol and propylene glycol, glycol ether solvents such as ethylene glycol monomethyl ether, glycol ether ester solvents such as ethylene glycol monomethyl ether acetate, amine solvents such as triethanolamine, and formamide. Water-based inks are known that improve drying resistance by incorporating water-soluble organic solvents such as amide solvents such as amide solvents, or hygroscopic inorganic compounds such as lithium chloride into an aqueous solution of water-soluble dyes. It was not possible to obtain a product that satisfactorily satisfies drying resistance. The reason for this is that glycol solvents generally have a high viscosity and a high boiling point, so the viscosity of ink used in large quantities increases, and when used in writing instruments that require low viscosity, ink flow is inhibited and the ink runs out. In addition, it is difficult to dry handwriting, and there is a limit to the amount that can be used, making it impossible to add enough to satisfy drying resistance.

Glycol ether solvents and glycol ether ester solvents generally have low surface tension, so handwriting tends to smear, and the ink may penetrate to the back side of the paper or smudge on the surface, making it impossible to obtain clear handwriting. It has drawbacks such as low dissolving power for dyes, making it impossible to obtain sufficient color development, and strong odor, and similarly to the above, it is not possible to add it in an amount sufficient to satisfy drying resistance.

Since amine solvents have an unpleasant odor peculiar to amines, they cannot be added in an amount sufficient to satisfy drying resistance.

Amide solvents undergo significant hydrolysis and lower PH, so they cannot be used for dyes that are highly PH-dependent. Furthermore, since it is highly corrosive to metals, it has the disadvantage that there are limits to the materials that can be used for writing instruments.

Hygroscopic inorganic compounds such as lithium chloride and calcium chloride react with dyes to form salts and reduce the solubility of dyes, making it difficult to prepare highly concentrated inks and requiring only a sufficient amount to satisfy drying resistance. cannot be added.

The inventors of the present invention have conducted various studies to solve the conventional problems described above, and have found that when a certain substance is included in an aqueous solution of water-soluble dye, the drying resistance is good and the viscosity increases rapidly. The present invention was completed based on the discovery that a water-based ink with excellent dye solubility can be obtained without the need for oxidation.

That is, the gist of the present invention is a water-based ink containing at least water, a water-soluble organic solvent, a water-soluble dye, and an organic polycarboxylic acid and/or a salt thereof.

Next, each component of the water-based ink of the present invention will be explained in more detail. As water-soluble dyes, most dyes such as acid dyes, direct dyes, and basic dyes can be used. Specific examples of acid dyes include Eiseneosin GH (CI45380), Nigrosin NB Conc (CI50420), solvable blue
OBB (CI42780), Soluble Blue OBC (C.
Direct dyes include Direct Deep Black EX (CI30235), Kayalus Black G Conch (CI35225), Direct Deep Black XA (similar to CI30235), and Diacotton First Orange WS (C .
I.29156), Phthalocyanine Blue G Conch (C.
I.22311), Nippon Orange GG Conch (C.
Basic dyes include Victoria Blue FB (CI44045), Methyl Violet FN (CI42535), and Rhodamine F4G (C.I.23375).
I.45160), etc., and these can be used alone or in combination with other water-soluble dyes, but direct dyes are particularly preferred in view of the water resistance and light resistance of the ink. The amount of water-soluble dye to be used varies depending on the purpose of use, but for example, when used as an ink for writing instruments, it is preferable to use it in an amount of 0.5 to 15% by weight based on the total amount of ink. is obtained.

Examples of organic polycarboxylic acids used in the present invention include cyclopentane-1,2,3,4-tetracarboxylic acid, tetrahydrofuran-1,2,3,4-tetracarboxylic acid, and tetrahydro-2,2,5,5-tetracarboxylic acid.
Tetracarboxylic acid, carboxymethylated products of sucrose and lactose, carboxymethylated products of gluconic acid, carboxymethylated products of polyhydric alcohols, benzenepolycarboxylic acids represented by mellitic acid, ethane-1,1,2,2 tetracarboxylic acid acid, butane-1,2,3,4 tetracarboxylic acid,
Propane-1,2,3-tricarboxylic acid, butane-
1,4 dicarboxylic acid, decane-1,10 dicarboxylic acid, sulfotricarballylic acid, sulfoitaconic acid, and alkali metal salts, ammonium salts, amine salts, etc. of the above-mentioned substances can be used. The amount used is 0.5 to 20% by weight, especially 1 to 20% by weight based on the total amount of ink.
15% by weight is desirable. If the carboxylic acid is less than 0.5% by weight, the effect of the carboxylic acid may not be expected;
This is because if the polycarboxylic acid or its salt is not completely dissolved, the ink viscosity may increase more than necessary and the ink may become unusable.

Next, water-soluble organic solvents are those that are compatible with water and are used as auxiliary agents, such as ethylene glycol, diethylene glycol, doriethylene glycol, propylene glycol, 1.3-butylene glycol, thiodiglycol, ethylene glycol, monomethyl ether, There are ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, formamide, solpit, sorbitan, acetin, glycerin, etc., and these can be selected and used as appropriate. The amount used is preferably 1 to 40% by weight based on the total amount of 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 composition, if you want to add a wetting effect to the ink and make the ink flow out more smoothly during writing (however, if the porosity of the pen tip is large, for example, the phenomenon of overflow of ink will occur),
Penetrants such as various anionic or nonionic surfactants are contained in an amount of 5% by weight or less based on the total amount of ink, and preservatives such as sodium pentachlorophenol, phenol, formalin, etc. are used to prevent inhibition of ink flow due to mold growth. If metal is used in the part of the writing instrument that comes into contact with the ink, a corrosion inhibitor such as benzotriazole or ethylenediaminetetraacetate may be added as appropriate to prevent corrosion of the metal. .

Ink can be manufactured by a simple operation of appropriately selecting the above-mentioned ink components according to the function and required characteristics of the object to be used, mixing and dissolving them, but it is easier to prepare ink by heating and stirring with appropriate heat. can.

Hereinafter, the present invention will be explained with reference to examples. In the examples, parts simply refer to parts by weight.

Example 1 (Black ink) Water 72.8 parts Ethylene glycol 15.0 Kayarasu. Black G Conc 7.0〃 (Direct dye, manufactured by Nippon Kayaku Kogyo Co., Ltd.) Decane-1.10 dicarboxylic acid 5.0〃 Noogen P 0.1〃 (Nonionic activator, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Pentachlorophenol sodium 0.1〃 Above When the mixture of each component was heated to 40-50℃, stirred for 1 hour, and filtered, the viscosity was 3.1cps (at 25℃).
The desired black ink could be obtained. When I filled this ink into a writing instrument similar to a commercially available felt-tip pen and wrote on paper, the ink flowed out smoothly, and even after removing the cap and leaving it in the air for 10 days, there was no smudging when writing. I was able to write it down. Further, the ink did not penetrate to the back side of the paper or bleed. However, when propylene glycol was used instead of decane-1.10 dicarboxylic acid, complete smearing occurred in 4 hours when the cap was removed and left in the atmosphere.

Example 2 (Black ink) Water 64.8 parts Diethylene glycol 15.0 Direct Deep Black Salt 10.0〃 Neugen P 0.1〃 (Nonionic activator, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Pentachlorophenol sodium 0.1〃 Example 3 (Green ink) Water 60.0 parts Diethylene glycol monomethyl ether
18.0〃 Phthalocyanine Blue-G Conch (CI74180)
6.0 part Mitsui. Acid Fast Yellow G Conc (CI18965) 1.0〃 Lithium Sulfoitaconate 15.0〃 Example 4 (Orange ink) Water 65.0 parts Ethylene glycol 20.0〃 Nippon Orange GG Conc (CI23375) 5.0〃 Triammonium Trimellistate 10.0〃 Above Examples 2, 3, and 4 were treated similarly to Example 1, with a viscosity of 2.9 cps (at 25°C), respectively.
We were able to obtain the desired inks of 3.2 cps (at 25°C) and 3.1 cps (at 25°C). Further, when the ink was filled in a writing instrument and written on paper in the same manner as in Example 1, the flow of the ink was slightly different, but the flow was good in all cases. In other respects, almost the same results as in Example 1 were obtained.

Although the present invention has been described above with respect to a water-based ink for writing instruments, it can also be applied to water-based inks for stamps, printing, etc.

Claims (1)

[Claims] 1. A water-based ink containing at least water, a water-soluble organic solvent, a water-soluble dye, and an organic polycarboxylic acid and/or a salt thereof.