JPS6152870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-based ink suitable for use in writing instruments, stamps, printing, and recorders. The invention relates to a water-based ink that has excellent properties.

Conventionally, for example, writing instruments, specifically writing instruments with pen nibs made of fibers, felt, monofilament, or capillary tube type writing instruments such as ballpoint pens and fountain pens, have been exposed to air during storage or when the cap is removed from the writing instrument body. There has been a need for a water-based ink that does not clog the ink flow path in the pen tip even when exposed to water for a long time, and allows the ink to flow out smoothly at all times, allowing for extremely smooth writing.

In order to meet this demand, water-soluble organic solvents such as glycol-based agents, glycol ether-based solvents, and glycol ether ester-based solvents, or hygroscopic inorganic compounds such as lithium chloride and calcium chloride are included in the aqueous solution of water-soluble dyes. Water-based inks with improved drying properties are known, but none have been able to provide sufficient drying resistance.

The reason for this is that glycol solvents generally have a high viscosity and a high boiling point, which increases the viscosity of the ink, and when used in the above-mentioned writing instruments that require low viscosity, the outflow of the ink is inhibited, causing the ink to run out. Moreover, it has drawbacks such as the handwriting is difficult to dry and the abrasion resistance after writing is poor, and there is a limit to the amount used, and it is not possible to add it in an amount sufficient to satisfy the 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 increasing viscosity and strong odor, and as mentioned above, it cannot be added in an amount sufficient to satisfy drying resistance.

Lithium chloride and calcium chloride react with dyes to form salts and reduce the solubility of dyes.
It becomes difficult to adjust the ink concentration to a high concentration, and if a high concentration ink is required after all, a disadvantage arises that is inconvenient for satisfying certain properties of dryness resistance.

Therefore, the inventors of the present invention have conducted various studies to solve the conventional problems mentioned above, and have found that when an N・N-dialkylethanolamine derivative is blended into an aqueous solution of a water-soluble dye, good drying resistance is achieved. The present invention was completed based on the discovery that a water-based ink that does not cause a sudden increase in viscosity and has good dye solubility can be obtained.

The present applicant previously filed an application for using amines in water-based ink (Japanese Patent Application No. 1975-75514......
-5130), but when comparing the invention of the application (hereinafter referred to as the invention of the earlier application) and the amines of the invention, the invention has the following advantages.

That is, the amines of the present invention are superior to the amines of the prior invention, with less odor and toxicity.

If unreacted raw material amine remains, since the basicity is low, it will not react with the composition (particularly dye) in the ink, and there is little possibility that by-products will occur and cause problems.

Since a lower alkyl group is selected for the amine, it exhibits properties as a weak activator and improves the solubility of direct dyes.

As described above, the amines of the present invention are superior to the amines of the prior invention in various respects.

That is, the gist of the present invention is a water-based ink in which an N·N-dialkylethanolamine derivative represented by the following general formula () is blended into an aqueous solution of a water-soluble dye.

General formula: (In the formula, R represents a lower alkyl group and n = an integer of 1 to 20.) Next, each component of the aqueous ink of the present invention will be explained in more detail.

Examples of N·N-dialkylethanolamine derivatives include adducts of N·N-dimethylethanolamine and 1 to 20 moles of propylene oxide, and adducts of N·N-diethylethanolamine and 1 to 20 moles of propylene oxide. can be mentioned.
All of these can be easily obtained by adding 1 to 20 moles of propion oxide to the corresponding N·N-dialkylethanolamine.

The amount of the N·N-dialkylethanolamine derivative used may be changed as appropriate depending on the purpose, but for example, when used as an ink for writing instruments, suitable results can be obtained when it is used in an amount of 0.5 to 50% by weight of the ink composition. , preferably 1.0 to 20% by weight.

When using the N/N-dialkylethanolamine derivative represented by the above general formula, the solubility of the dye is increased, the hygroscopicity is improved, and the dye in the ink does not coagulate at room temperature, so it can be used for a long time. An ink with so-called excellent drying resistance is obtained in which the ink at the pen tip does not evaporate even if the pen is removed and left in the atmosphere.

In this way, the solubility of all dyes, acidic, basic and direct, can be increased. In particular, it becomes possible to use direct dyes, which have not been used often due to their poor solubility, and therefore, by using these dyes, inks with good water resistance and drying resistance can be obtained.

Most of the water-soluble acid dyes, basic dyes, and direct dyes can be used as water-soluble dyes. Specific examples of acid dyes include Eiseneosin GH (CI45380) and Water Black #21 ( Mixed dyes of CI15985, 42090, 42745), Nigrosine NB Conch (CI50420), Water Blue #9 (CI42090), Water Pink #2 (CI45410), Kayactatrazine (C.
I.19140) etc. Victoria Blue F4B (CI42563), Victoria Blue as a basic dye
FB (CI44045), Methyl Violet FN (C.
I.42535), rhodamine 6GCP (CI45160), etc. Direct dyes include Water Black #100 (CI35255), Direct Deaf Black EX (CI35225), Direct Deaf Black XA (manufactured by Sumitomo Chemical Co., Ltd.), and Direct First Black Conc (CI27720). It can be used alone or in combination with other water-soluble dyes. The amount of water-soluble dye to be used may be changed depending on the purpose, but for example, when used as an ink for writing instruments, it should be 0.5 to 0.5 of the total ink composition.
Good results are obtained when using 15% by weight.

As mentioned above, the present invention greatly improves drying resistance by adding and blending the compound represented by the general formula () into an aqueous solution of a water-soluble dye. , glycol ether type, glycol ether ester type,
Dimethyl sulfoxide, 2-pyrrolidone, N
A solvent such as -methyl-2-pyrrolidone or a preservative may be appropriately selected and used.

Examples of the present invention will be described below regarding ink for writing instruments.

In addition, in the examples, the term "parts" simply indicates "parts by weight."

Example 1 Water black #21 (CI15985, 42090,
42745 mixed dye, manufactured by Orient Chemical Industry Co., Ltd.)
6.5 parts Nigrosine NB Conc (CI50420, Sumitomo Chemical
Co., Ltd.) 1.0〃 Formalin (preservative) 1.0〃 Ethylene glycol 20.0〃 N・N-dimethylethanolamine and propylene oxide 10 mole adduct 10.0〃 Water 61.5〃 Among the above ingredients, first mix ethylene glycol and water. Next, the remaining components are mixed into the mixed solution and stirred while heating at 40 to 50° C. for about 1 hour to form an ink. This ink has good color strength, good adhesion properties on writing paper, and does not bleed or bleed when used on writing paper. In addition, the drying resistance of this ink can be tested by removing the cap from a writing instrument made of fiber, felt, monofilament, porous, or having a capillary tip and leaving it for 10 days at a temperature of 20°C and humidity of 65%. I was able to write without the pen tip drying out even when I was using the pen.

An ink obtained by removing the 10 mole adduct of N.N-dimethylethanolamine and propylene oxide from this formulation and adding that amount of water dried under the same conditions in about one day.

Example 2 Water black #100 (CI35255, manufactured by Orient Chemical Industry Co., Ltd.) 6.5 parts Sodium pentachlorophenol (preservative)
1.0〃 Ethylene glycol 20.0〃 N.N-diethylethanolamine and propylene oxide 5 mol adduct 20.0〃 Water 52.5〃 The ink prepared by mixing, heating and stirring the above components as in Example 1 has good writing characteristics. Even if the pen was left for 10 days with the cap removed under the same conditions as in Example 1, the pen tip did not dry out and writing was possible. An ink obtained by removing the 5 mole adduct of N·N-diethylethanolamine and propylene oxide from this formulation and adding that amount of water was dried in about one day under the same conditions.

Example 3 Victoria Blue FB (manufactured by BASE) 6.0 parts Formalin 1.0〃 Diethylene glycol 20.0〃 N.N-dimethylethanol and propylene oxide 5 mol adduct 20.0〃 Water 53.0〃 The above components were mixed as in Example 1, heated and stirred. The resulting ink had good writing characteristics, and even if it was left for 30 days with the cap removed under the same conditions as in Example 1, the pen tip did not dry out and writing was possible.
Note that an ink obtained by removing the 5 mole adduct of N·N-dimethylethanolamine and propylene oxide from this formulation and adding that amount of water dried under the same conditions in about 5 days.

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

Claims (1)

[Scope of Claims] 1. A water-based ink characterized by containing an N·N-dialkylethanolamine derivative represented by the following general formula (). General formula: (In the formula, R represents a lower alkyl group and n = an integer of 1 to 20.)