JPH05140498A - Water-base ink - Google Patents

Abstract

PURPOSE:To provide a water-base ink which is excellent in the capability of wetting synthetic resins, can give clear handwriting without defects such as blotting of writing, and can display these performances in a relatively low viscosity range. CONSTITUTION:The objective ink comprises maltosylcyclodextrin, a colorant and water as essential components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous ink used for writing instruments and the like.

[0002]

2. Description of the Related Art Water-based inks for writing instruments are required to have high affinity with synthetic resins, that is, high wettability.
For example, water-based ink is filled into the ink cartridge of a fountain pen molded of polyethylene resin, etc.
If the wettability of the water-based ink is low, the ink does not move smoothly in the cartridge and remains, resulting in poor writing. Further, like a pen core, a part having an ink conduction path in which a capillary action functions is often formed of a synthetic resin such as a polyacetal resin or a polyamide resin. It doesn't conduct well,
Similarly, there is a problem that writing defects occur.

[0003]

Therefore, in order to improve the wettability of water-based ink, it has been widely practiced to add a surfactant to the ink. However, when a surfactant is added, at the same time, the surface tension is remarkably lowered, so that the handwriting is blurred at the time of writing, and "shattering" or "scattering" of the ink occurs due to a slight shock or vibration.

In order to solve such a problem, it is also attempted to increase the viscosity of the ink by adding a water-soluble resin such as polyvinyl alcohol, a cellulose derivative and dextrin together with the surfactant. The smooth outflow of As described above, when the surfactant is used as the main agent for improving the wettability, various problems are caused due to the decrease in the surface tension, so that there is a limit to the improvement of the wettability, and an aqueous ink having sufficient performance is still available. The reality is that it has not been obtained.

In view of such circumstances, the present invention has excellent wettability to synthetic resin, can obtain clear handwriting without defects such as bleeding of handwriting, and exhibits these performances in a relatively low viscosity range. The purpose is to provide a possible water-based ink.

[0006]

To achieve the above object, the water-based ink of the present invention contains maltosyl cyclodextrin, a colorant and water as essential components.

[0007]

The maltosyl cyclodextrin is a kind of oligosaccharide, and among the many sugars, it was found that it is the most effective for achieving the object of the present invention, and the present invention was completed. That is, the addition of maltosyl cyclodextrin can remarkably improve the affinity for various synthetic resins, that is, the wettability. Therefore, when the water-based ink is filled in the ink cartridge of a fountain pen formed of polyethylene resin or the like, the ink is smoothly moved in the cartridge. In addition, the surface tension is hardly changed, and the handwriting does not bleed during writing, and the ink does not "flatter" or "scatter" due to a slight shock or vibration. Moreover, the viscosity of the ink is hardly increased as compared with sugars such as dextrin, and even if the addition amount is increased, the viscosity of the ink is slight.

The amount of maltosyl cyclodextrin added is effectively 0.5 to 20% by weight in the ink formulation, preferably 3 to 15% by weight. If the amount is less than 0.5% by weight, the effect is small. On the contrary, if the amount exceeds 20% by weight, not only the effect is small and it is wasteful, but also maltosyl cyclodextrin may be precipitated due to aging, and the stability is stable. Becomes worse.

Any colorant may be used as long as it can be dissolved or uniformly dispersed in water as a solvent, and various acid dyes, direct dyes, basic dyes, and pigments such as carbon black and various processed pigments are used. it can.

As described above, the essential components of the water-based ink are maltosyl cyclodextrin, a colorant and water, but various components may be added as necessary. That is, in order to suppress evaporation, a water-soluble organic solvent, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, glycerin, 2-pyrrolidone, sulfolane, dimethyl sulfoxideon, triethanolamine, Diethanolamine, monoethanolamine and the like can be added in appropriate amounts. In addition, as a stabilizer for colorants, urea, hydrotropes such as dimethyl sulfone, as a fungicide,
Sodium dehydroacetate, carboxylic acid, sodium benzoate and the like can be added in appropriate amounts. Furthermore, E. D. T. A suitable amount of an anticorrosive agent such as A, casein, shellac, maleic acid resin, cellulose derivative, and a viscosity modifier such as polyvinyl alcohol can be added.

[0011]

EXAMPLES Examples and comparative examples of the water-based ink of the present invention will be explained below and their performances will be compared. All parts in the formulation examples are parts by weight.

Example 1 Water Black # 100-L 10 parts Ethylene glycol 2 parts Maltosyl cyclodextrin 5 parts Phenol 0.1 part Water 82.9 parts The above components are dissolved at room temperature using a stirrer to make a fountain pen. I got a black ink. [Comparative Example 1] A black ink for fountain pens was obtained by the same method, which was composed of components excluding maltosyl cyclodextrin from the formulation of [Example 1].

Example 2 Soluble Blue OBC 2 parts Glycerin 1 part Maltosyl cyclodextrin 10 parts Phenol 0.1 part Water 86.9 parts The above components are dissolved at room temperature using a stirrer to prepare a blue fountain pen. I got ink. [Comparative Example 2] A blue ink for fountain pens was obtained by the same method, which was composed of components excluding maltosyl cyclodextrin from the formulation of [Example 2].

Example 3 Water red # 9 2 parts Propylene glycol 2 parts Maltosyl cyclodextrin 5 parts Phenol 0.1 part Water 90.9 parts The above components are dissolved at room temperature using a stirrer to prepare a fountain pen. I got red ink. [Comparative Example 3] A red ink for fountain pens was obtained by the same method, which was composed of components excluding maltosyl cyclodextrin from the formulation of [Example 3].

An ink replaceability test and a dripping resistance test were conducted using the above 6 types of water-based inks. In the ink replaceability test, a polyethylene resin ink carridge is filled with half its capacity and sealed. And
After standing for 24 hours in a vertical state, it was inverted and the situation in which the ink was moved alternately was examined. In addition, in the anti-bottling resistance test, a polyethylene resin ink carridge that was filled with each ink was attached to a fountain pen, and the fountain pen was left at 0 ° C for 1 hour with the pen body facing upwards and then inverted. It was left standing in a downward position at 30 ° C. for 1 hour, and the presence or absence of ink dripping into the cap was examined.

The results are shown in Table 1. The results of both tests were good in all Examples, and all Comparative Examples were poor. That is, in each of the examples, the wettability with respect to the synthetic resin is excellent, and clear handwriting can be obtained without defects such as handwriting bleeding.

[Table 1]

[0017]

As described above, since the water-based ink of the present invention contains maltosyl cyclodextrin, a colorant and water as essential components, it has excellent wettability with synthetic resin and does not have defects such as handwriting bleeding. You can get clear and clear handwriting.

Claims (1)

[Claims] 1. A water-based ink containing maltosyl cyclodextrin, a colorant, and water as essential components.