JPS61246271A - Water-based pigment ink for writing utensil - Google Patents

Abstract

PURPOSE:To provide an ink having improved dispersion stability and drying resistance, by blending a pigment, a water-soluble amine salt or ammonium salt of a copolymer, a water-soluble org. solvent and water. CONSTITUTION:The titled ink is formed from pref. 5-20wt% pigment (a), 0.5-3.0wt% water-soluble amine salt, ammonium salt or metal salt (b) of a copolymer composed of a hydrophilic addition-polymerizable monomer and styrene and/or a styrene derivative, 15-35wt% water-soluble org-solvent (c) and water (d), each quantity being based on the entire quantity of ink. Examples of the hydrophilic addition-polymerizable monomers are acrylic acid, methacrylic acid and maleic acid. Examples of the styrene derivatives are alpha-methylstyrene and alpha-ethylstyrene. Examples of the solvents are glycols, glycol ethers and glycerol.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a water-based pigment ink for writing instruments, particularly those using fiber bundles or porous materials in the nib, and more particularly relates to a water-based pigment ink for writing instruments that uses a fiber bundle or a porous material in the pen tip, and more particularly, This invention relates to a water-based pigment ink for writing instruments with excellent drying properties.

Prior art) Water-based pigment inks have been used for various purposes due to their excellent water resistance and light resistance.

(Problems to be Solved by the Invention) However, when the ink for writing instruments is used at a low viscosity, there is a problem that the dispersibility of the pigment is unstable and it tends to aggregate, making writing impossible over time. or.

The nib uses fiber bundles such as natural hair or artificial hair, or porous materials such as urethane or sponge.

(Means for Solving the Problem) The present inventors have conducted various studies to improve the dispersibility and drying resistance of the above-mentioned aqueous pigment ink, and as a result, they have found that hydrophilic addition-polymerizable monomers, styrene and/or By using a water-soluble amine salt, ammonium salt, or metal salt of a copolymer consisting of a styrene derivative monomer, the dispersion stability of the ink can be improved, and by using a specific amount of these, the pen tip can be *
The present invention was completed based on the discovery that the drying resistance of a pen (when a fiber bundle or a porous material is used in the nib) is improved. That is, in the present invention, pigment and;
．． Ink with a water-soluble amine salt, ammonium salt or metal salt of a copolymer consisting of 5 to 3.0% by weight of a hydrophilic addition polymerizable monomer and a styrene and/or styrene derivative monomer; The gist of the invention is a water-based pigment ink for writing instruments, which comprises at least 15 to 35% by weight of a water-soluble organic solvent based on the total amount; and water.

(Function) Although it is not clear why the aqueous pigment ink for writing instruments of the present invention has excellent dispersion stability and drying resistance, it is inferred as follows.

The water-soluble amine salt, ammonium salt, or metal salt of a copolymer consisting of a hydrophilic addition-polymerizable monomer and a styrene and/or styrene derivative monomer used in the present invention shares a hydrophilic portion and a hydrophobic portion. This gives the pigment good dispersibility.

It is thought that dispersion stability is improved due to improved wetting to water and water-soluble organic solvents. In addition, the amount of the water-soluble amine salt, ammonium salt, or metal salt of the copolymer used is α5 to 3.0% by weight based on the total amount of the ink, and the amount of the water-soluble organic solvent used is 15 to 3.0% by weight based on the total amount of the ink. 35% by weight
Therefore, it is thought that drying of ink at the pen tip, especially at a pen tip using a fiber bundle or porous material, is prevented as much as possible.

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

As the pigment, all commercially available pigments can be used, and specific examples thereof are listed below.

Carbon black, phthalocyanine blue (C21,7
4160), Phthalocyanine Green CC.

1.74260), Hansa Yellow 3 G (0,I
.

11670), Disazo Yellow R (0, I.

21100), Permanent Red 4 R (0, I.

12335), Brilliant Carmine 6 B (0
゜1.15850), Quinacridone Red (0,I
.

46500) and the like can be used, and the amount used is preferably 5 to 20% by weight based on the total amount of the ink.

Incidentally, the proportion of each type of pigment to be used is selected as appropriate.

A water-soluble amine salt of a copolymer consisting of a hydrophilic addition polymerizable monomer and a styrene and/or styrene derivative monomer,
Ammonium salt or metal salt is used as a dispersant, and the amount used is 0.5 to 3.0% based on the total amount of ink.
It is 0% by weight. If it is less than 0.5% by weight, the pigment dispersion power will decrease and the stability over time will deteriorate. If the amount exceeds 50% by weight, a thin resin film will be formed at the fiber bundle or porous pen tip, resulting in poor ink flow and blurred handwriting.

Examples of hydrophilic addition polymerizable monomers include acrylic acid,
Examples of styrene and/or styrene derivative monomers include methacrylic acid, ethacrylic acid, maleic acid, and fumaric acid.

Styrene, a-methylstyrene, a-ethylstyrene,
Examples include serprobylstyrene, a-butylstyrene, and a-pentylstyrene. still.

The two components can be combined arbitrarily.

Glycol solvents are water-soluble organic solvents.

Glycol ether type i agents, glycol ether ester type solvents, glycerin, pyrrolidone, etc. can be used.
One or more types of these can be used, and the amount used is 15 to 35% by weight based on the total weight of the ink. 1
If it is less than 5% by weight, the moisturizing effect will be reduced and the dryness resistance will be poor.

If the amount is more than 35% by weight, the viscosity of the ink at the nib increases as it dries at the nib, resulting in poor ink flow and blurred handwriting.

Water is used as the main solvent.

In addition to the above ingredients, if necessary, preservatives such as 1,2-benzisothiazolin-3-one, pentachlorophenol-acresol, rust preventives such as benz) IJ azole, and various surfactants may be added. Various additives may be used as appropriate.

Next, in the method for producing the water-based pigment ink for writing instruments of the present invention, the above-mentioned components are mixed and ground using a common dispersing machine such as a ball mill, roll mill, sand mill, super mill, Dyno Mill water attritor, etc. 9 obtained by dispersing.

(Example) The present invention will be described in detail below based on Examples, where "parts" in the examples indicate "parts by weight."

Examples 1 to 4 shown in Table 1 below. Each component of Comparative Examples 1 to 4 was premixed by stirring for 2 hours.

Furthermore, Examples 1 and 4. Comparative Examples 1 and 4 were processed in a sand mill for 10
Time, Example 2.3. Comparative example 2.3 is 1 in a ball mill.
After grinding for 5 hours, coarse particles were removed by passing through the mixture to obtain a water-based pigment ink for writing instruments.

Table 1 (Unit: parts) (Effects of the invention) Above Examples 1 to 4. Table 2 shows the results of the dispersion stability test and drying resistance test of the inks obtained in Comparative Examples 1 to 4.

Table 2 *1 Dispersion stability test Ink was placed in a test tube and sealed, heated at 100°C for 94 hours, returned to room temperature, and dripped onto a membrane filter; unheated ink dripped onto a membrane filter. The dispersion state of the pigment was compared.

○: No change ×: Aggregation *2 Drying resistance test Fill a commercially available brush pen (SF-15, manufactured by Bentel ■, nib: urethane porous material) with ink, remove the cap,
After being left horizontally for 5 hours indoors (20°C ± 5°C, humidity 40% ± 5%), I wrote on it and compared it with the written line before leaving it.

○: Almost no change Δ: Occurrence of blurring ×: Almost impossible to write As explained above, 2 The water-based pigment ink for writing instruments of the present invention has excellent dispersion stability and drying resistance, In particular, a writing instrument using a fiber bundle or a porous material for the nib has excellent nib drying resistance.

Claims (1)

[Claims] Pigment; water-soluble amine salt of a copolymer consisting of a hydrophilic addition-polymerizable monomer and a styrene and/or styrene derivative monomer in an amount of 0.5 to 3.0% by weight based on the total amount of the ink; ammonium With salt or metal salt; 1 per total amount of ink
A water-based pigment ink for writing instruments comprising at least 5 to 35% by weight of a water-soluble organic solvent and water.