JPS61123683A - Aqueous ink composition - Google Patents

Abstract

PURPOSE:The titled composition suppressing evaporation of ink at a pin point, crystal growth of dye or secondary aggregation of pigment, having no fear of blurred writing and writing impossibility, containing a fixed amount of an N,N'-dialkylpropyleneurea. CONSTITUTION:0.1-50pts.wt., preferably 10-30pts.wt. (based on 100pts.wt. ink composition) is blended with water and dye or pigment, and, if necessary, a moisture absorbing agent, and other additives, uniformly dissolved or dispersed at room temperature, to give the aimed composition.

Description

[Detailed Description of the Invention] [Object of the Invention] The present invention uses a water-based ink composition, especially for a marking pen, so that even if you forget to close the cap or the cap falls off due to panic, the pen tip can be used. To provide an aqueous ink composition for marking, which suppresses ink evaporation, crystal growth of dyes, and secondary aggregation of pigments, and does not cause blurring or inability to write over a long period of time.

[Structure of the invention]

This invention contains 0.5 to 6 N,N-dialkylpropylene urea represented by the general formula CI) per 100 parts by weight of the composition.
This is an aqueous ink composition containing 0 parts by weight as an essential component.

The symbol represents hydrogen or an alkyl group having 1 to 8 carbon atoms, and includes propylene urea, N,N-dimethylpropylene urea, N,N-
Examples include diethylpropylene urea. Hereinafter, it will be abbreviated as propylene urea. ) Propylene ureas are liquid at room temperature, have extremely low volatility, and have high solubility in water.When added to water-based ink, they increase the solubility of dyes in water, suppressing ink evaporation and dye crystallization. It also seems to have the effect of preventing secondary agglomeration of pigments, and propylene ureas themselves do not crystallize, so when used in a marking pen, even if the cap is left uncovered for a long period of time, it will not cause blurring or inability to write. do not have.

Propylene ureas can be used in an amount of 0.5 to 50 parts, preferably 10 to 80 parts, per 100 parts by weight (hereinafter, parts by weight are simply referred to as parts) of the ink composition.

If the amount of propylene urea is in excess of 60 parts, the ink will bleed when written on paper, and if it is less than 5 parts, the ink evaporation suppressing effect will be lost.

In the present invention, all pigments, acid dyes, direct dyes, and basic dyes that are normally used in marking pen inks can be used as colorants, and pigments include inorganic pigments such as titanium oxide, Bengara, and ultramarine, and caramel.

Organic pigments such as Miso 6B and phthalocyanine green, C!
, 1. Acid Red 87.92. C! , 1. Acid Yellow 28.0.1. Acid Bluef.

0, 1. Acidic dye such as Acid Black 2, (:!,
I.

Direct black 19.88. (3, I, Direct Dye 44.87. C, 1, Direct dye such as Direct Bluff 1, O, 1, Basic Red 1, O, 1,
Basic Nilow 1, O, 1, Basic Blue 1
Examples include basic dyes such as.

The amount of coloring agent used may vary from 0.1 to 15 parts, preferably from 0.1 to 10 parts per 10 G parts of the composition, depending on the desired concentration.

In the present invention, it is desirable to use a wetting agent commonly used as ink for marking pens in combination with propylene urea, as this has a synergistic effect in preventing blurred writing. Wetting agents include ethylene glycol, diethylene glycol,
Examples include triethylene glycol, propylene glycol, and glycerin.

In addition, nonionic activators or anionic activators, preservatives such as potassium sorbate, I'H such as sodium carbonate, etc., to improve dispersion of pigments and dissolution of dyes, as necessary.
Of course, rust preventives such as A-detergent 4-benzotriazole, which are commonly used as additives in marking pen inks, may also be used.

To prepare the ink composition of the present invention, dyes or pigments, propylene ureas, and if necessary a moisture absorbent and other additives are added to water and stirred at room temperature to uniformly dissolve or disperse.

Next, examples will be shown to further clarify the present invention.

Example 1 10 parts of C,1, Direct Blue and 1 part of N,N-dimethylpropylene urea were added to 89 parts of water, and the mixture was stirred at room temperature for 1 hour to obtain a uniform solution, thereby obtaining a blue ink composition.

Comparative Example 1 89 parts of water with 0, 1. Direct Blue 10 parts propylene glycol
A blue ink composition was obtained in the same manner as in Example 1 with the addition of 1 part.

Comparative Experiment Using the ink compositions of Example 1 and Comparative Example 1, a marking pen with a polyester fiber nib and a polyester fiber ink absorber was filled with each ink composition and heated at 20°C 160 with the cap removed. %RH.

The pen using the ink of Comparative Example 1 became blurred overnight and could no longer be written on, but the pen using the ink of Example 1 was able to write without any problem even after one week.

Example 2 Water 58.9 parts Newcoxin 8 parts N,N-dimethylpropylene urea tOS ethylene glycol
10 parts nonionic activator 0.
1 part (trade name, Neugen P1, manufactured by Dai-Kogyo Seiyaku) Sodium benzoate 1.0 part A red ink composition was obtained according to Example 1.

Example 8 Water 66.7 parts Direct Black 18 9 parts (trade name, Kayaras Black G Conc) N,N'-dimethylpropylene urea 16 parts Glycerin 5 parts Nonionic surfactant 0.1 part (trade name,
Score roll #400, manufactured by Kao Atlas) Potassium sorbate 0.2 parts A black ink composition was obtained according to Example 1.

Example 4 Water 67.9 parts Titanium oxide 18 parts (trade name, Titanium FC50, manufactured by Furukawa Mining Co., Ltd.) N,N-dimethylpropylene urea 15 parts Diethylene glycol
6 parts Nonionic surfactant 0.1 part (trade name, Noniolite POIO) Sodium benzoate 1 part A white ink composition was obtained according to Example 1.

Claims (1)

[Claims] An aqueous ink composition containing 0.5 to 50 parts by weight of N,N-dialkylpropylene urea per 100 parts by weight of the composition.