JPS62101671A - Water ink composition for writing utensil - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which allows the ball and the ball seat of a ball point pen to smoothly cooperate with each other to thereby prevent the seat from being worn and prolong the life of the pen, by blending a specified lubricant with water ink contg. a pigment, an aq. medium, etc. CONSTITUTION:A hydroxy acid such as malic acid, tartaric acid, citric acid, etc. is esterified with butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl or octadecyl alcohol to obtain a mono- or dialkyl ester of the hydroxy acid having at least one OH group and at least one free COOH group. 0.1-10wt% said ester is blended with water ink contg. 3-20wt% inorg. or org. pigment, 5-40wt% aq. medium (e.g., ethylene glycol) and optionally a hygroscopic material, a rust inhibitor, a mildewproofing agent, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a water-based ink for writing instruments using a small amount of pigment as a coloring agent, and more specifically, to a water-based ink for writing instruments using a pigment as a coloring agent.

Optimal performance for ballpoint pens with metal tips.

For example, it relates to a water-based ink for violet marking instruments that allows many characters to be printed 9 Y because the wear of the ball seat due to the rotation of the ball is small.

(Prior art and its problems) As a writing instrument using a conventional metal tip, there is a water-based metal ballpoint pen that uses water-based ink consisting of pigment and an aqueous medium. 4Z of the hard ball and ball catch Because the 4Z sliding is not smooth, the pole catch wears out during writing and many characters have a disadvantage.In order to further improve this defect, There are countermeasures such as adding an activator as an agent and increasing the viscosity by increasing the amount of glycols in the ink. (2) Ink viscosity tends to be disadvantageous for quick writing and writing at low temperatures.

It was not a perfect countermeasure.

(Means for Solving the Problems) The present invention was completed as a result of intensive research to solve the above-mentioned problems, and uses a monoalkyl ester of a specific oxyacid, By using a dialkyl ester, the lubricity of the water-based ink is increased, so there is less wear on the cemented carbide ball and the pole seat of the metal tip, and it is therefore possible to write many characters. Furthermore, since these oxyacid monoalkyl esters and dialkyl esters have different activators, they do not lower the surface tension of the water-based ink, so handwriting does not bleed, and while they are esters of acids with hydroxyl groups, they also contain free carboxyl groups. It also has good compatibility with aqueous media (,
It provides lubricity to water-based ink without thickening it.

That is, the gist of the present invention is a water-based ink for writing instruments, which is characterized in that the water-based ink comprises at least a pigment and contains a monoalkyl ester or dialkyl ester of an oxyacid as a lubricant.

(Structure of the invention) Next, the present invention will be explained in detail.

As the pigment used as the black coloring agent in the present invention, conventionally known general inorganic pigments and organic pigments can be used. Examples of the inorganic pigment include carbon plastic 7, chromium dilo, molybdenum red, ultramarine, navy blue, and titanium oxide. etc., but
Organic pigments include Hansa Yellow, Resole, Do, Disazo Yellow, Quinacridone, and Phthalocyanine.

Thioindigo etc. can be used. The amount of these pigments used is preferably 3 to 20% by weight based on the total amount of the ink.

Aqueous media include ethylene glycol, diethylene glycol, and triethylene glycol.

Polyhydric alcohols such as propylene glycol, glycerin and thiodiethylene glycol, cellsolves such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, carbitols such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether, and acid amides such as formamide and acetamide. These types can be used alone or in combination. The amount of these aqueous media to be used is preferably 5 to 40% by weight based on the entire ink stage.

When the oxyacid is malic acid, monoalkyl esters and dialkyl esters of oxyacids that are the gist of the present invention include monobutyl esters, monopentyl esters, monohexyl esters, monohebutyl esters, monooctyl esters, Monononyl ester, monodecyl ester, monododecyl ester, monotetradecyl ester, monohexadecyl ester.

Monooctadecyl ester can be used. Tartaric acid and citric acid are monobutyl ester, diptyle ester, monopentyl ester, cyhentyl ester, monohexyl ester, dihexyl ester, monoheptyl ester, diheptyl ester, monooctyl ester, dioctyl ester, monononyl ester, dinonyl ester, Monodecyl ester, didecyl ester, monododecyl ester, didodecyl ester, monotetradecyl ester, ditetradecyl ester, monohexadecyl ester, dihexatenyl ester, monooctadecyl ester, dioctadecyl ester can be used.

It is important that the oxyacid ester of the present invention has a hydroxyl group and at least one free carboxyl group, and the amount used thereof is preferably 01 to 10% based on the total amount of the ink.

In addition, hygroscopic substances such as urea and urea derivatives, rust preventive agents, antifungal agents, etc. can also be used as necessary.

The aqueous ink composition for writing instruments of the present invention consists of the above-mentioned components, and a known method can be used for its production. That is, each component of the water-based ink is mixed and ground using a known dispersing machine 1, such as a ball mill, homomixer, sand grinder, speed line mill, or roll mill.

It can be easily prepared by removing coarse particles by centrifugation.

(Example) The present invention will be specifically explained by referring to Examples.

In the examples, "part J" represents "part by weight."

Example 1 Carbon black 10 parts styrene
Monoethanolamine salt of methacrylic acid copolymer (molar ratio 2:1) 10 parts Malic acid monooctyl ester 1 part ethylene glycol 10 parts Benzotriazole
01 part water
689 parts The above ingredients were placed in a small pot mill and dispersed for 100 hours, and then centrifuged to remove coarse carbon black particles.
A black water-based ink for bamboo markings with a pigment content of 75% by weight was obtained.

Comparative Example 1 Instead of malic acid monooctyl ester used in Example 1, ethylene oxide 2 of 7-nylphenol in the same i was used.
Using the 0 mol adduct, 111 L of the same was strained to obtain a black water-based ink for writing instruments.

Example 2 Polychlorinated copper phthalonanine 12 parts styrene ~
8 parts ammonium salt of maleic acid copolymer (mole ratio 3:1) Mo7 dotenyl citric acid ester 5 parts propylene glycol 15 parts water
72 parts The above ingredients were placed in a small sand grinder and dispersed for 6 hours, followed by centrifugation to remove coarse polychlorinated copper phthalocyanine particles, thereby producing a green water-based writing ink containing 5 pigments and 9.0% by weight. Obtained.

Specificity Example 2 A green water-based ink for writing instruments was obtained in the same manner as in Example 1, except that the same amount of glycerin was used in place of the monododecyl citric acid ester used in Example 1.

Example 3 Quinacridone 15 parts Monomethylamine salt of styrene-acrylic acid copolymer Dibutyl tartrate 2 parts Ethylene glycol 10 parts Benzotriazole
05 parts pentachlorophenol-N
a Salt 0. + Hot water
62.4 parts The above ingredients were dispersed in a roll and centrifuged to remove coarse quinacridone particles, resulting in a pigment content of 100% by weight.
A red water-based ink for writing instruments was obtained.

Comparative Example 3 A red aqueous ink for writing instruments was obtained in the same manner as in Example 6, except that the same amount of water was used in place of the tartaric acid dibutyl ester used in Example 6.

Example 4 Copper phthalonanine 12 parts styrene
8 parts Li-lium salt of 7M combination of maleic acid (molar ratio 2:1) Glycerin 5 parts Ethylene glycol 5 parts Citric acid monooctyl ester 3 parts Water
67 parts The above ingredients were placed in a small sand grinder, dispersed for 4 hours, and then centrifuged to remove coarse copper phthalocyanine particles.

A blue water-based ink for writing instruments having a pigment content of 89% by weight was obtained.

Comparative Example 4 Instead of the citric acid monooctyl ester used in Example 4, the same amount of sorbitan laurate was used, and the same v:
Then, a black water-based ink for rod marking tools was obtained.

(Effects of the Invention) Each of the water-based inks for writing instruments obtained in Examples 1 to 4 and Comparative Examples 1 to 4 was filled into a water-based ballpoint pen having a metal tip and tested. Table 1 shows the results.

Table 1 (average of n = 5) (Note) The prototype water-based ink for writing instruments was filled into a writing instrument made of nickel silver with a 0.5 mm carbide ball, and JIS P
100I load on 3201 paper! , a marked line was written under the conditions of a writing angle of 70 degrees and a speed of 7 ay+/sec, and the change in ball ejection t was evaluated for chip wear.

JIS for writing instruments filled with water-based ink for rice 2 writing instruments
P3201 Paper K Draw 10 straight lines at 30 cm/sec and evaluate the state of handwriting (fading).

+6 JIS writing instruments filled with water-based ink for writing instruments
Draw a straight line on a sheet of paper and compare the width of the line immediately after writing P320 and 20 seconds after writing.

evaluate.

Patent original person Pentel Co., Ltd.

Claims (4)

[Claims] (1) A water-based ink composition for writing instruments, characterized in that the water-based ink comprises at least a pigment and contains a monoalkyl ester or dialkyl ester of an oxyacid as a lubricant. (2) In the monoalkyl ester or dialkyl ester of an oxyacid used as a lubricant, the oxyacid is
The aqueous ink composition for writing instruments according to claim 1, characterized in that the ink composition contains malic acid, tartaric acid, and citric acid. (3) In the monoalkyl ester or dialkyl ester of an oxyacid used as a lubricant, the alkyl ester group is butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, or octadecyl. A water-based ink composition for writing instruments according to claim 1. (4) The amount of monoalkyl ester or dialkyl ester of oxyacid used is 0.1 to 10% by weight in the water-based ink.
The aqueous ink composition for writing instruments according to claim 1, characterized in that: