JPH05148443A - Pigment ink composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition capable of providing drawn line excellent in water resistance when used for writing tool and excellent in long- term disperse stability of a pigment by blending pigment ink using a polyhydric alcohol (derivative) as a solvent with a ketone resin. CONSTITUTION:The objective composition contains (A) a solvent selected from a polyhydric alcohol and a polyhydric alcohol derivative (e.g. ethylene glycol or glycerin), (B) a ketone resin, (C) a dispersing agent (e.g. rosin, PVA or surfactant) and (D) a pigment. The component B is blended in a ratio of 0.2-25wt.% based on total amount of the composition. Generally, the component (D) and the component (C) are each preferably blended in ratios of 2-70wt.% based on total amount of the composition and 0.5-500wt.% based on the component (C).

Description

Detailed Description of the Invention

[0001]

The present invention relates to a writing instrument, a stamp stand,
The present invention relates to a pigment ink composition suitable for applications such as recorders.
More specifically, it relates to a pigment ink composition using a polyhydric alcohol, a polyhydric alcohol derivative or the like as a solvent.

[0002]

2. Description of the Related Art Conventionally, as an ink used for a writing instrument, a stamp stand, a recorder, etc., it is generally known that a dye is used as a colorant. However, inks using dyes are inferior in fastness such as bleeding of drawing lines, light resistance, and water resistance. Therefore, inks using pigments as colorants have been studied. An ink using a pigment as a colorant can solve some of the drawbacks when a dye is used. For example, with regard to water resistance, the pigment or dispersant used,
It may be insufficient depending on the type and blending amount of the solvent, and improvement has been desired. In particular, in inks using a polyhydric alcohol or a polyhydric alcohol derivative as a solvent among pigment inks, for example, when the pigment ink is used for a writing instrument, a stamp stand, a recorder, etc., the water resistance of the drawn line is not sufficient. It was

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and there is a drawback that a pigment ink using a polyhydric alcohol or a polyhydric alcohol derivative as a solvent has poor drawing line water resistance. A solution to the problem is to provide a pigment ink composition having excellent pigment dispersion stability for a long period of time and having good water resistance.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that at least one or two or more selected from polyhydric alcohols and polyhydric alcohol derivatives are used as a solvent. The inventors have found that the problem can be solved by including a ketone resin in the pigment ink, and completed the present invention.

That is, the pigment ink composition of the present invention is
At least one or more solvents selected from polyhydric alcohols and polyhydric alcohol derivatives, ketone resins,
It contains a dispersant and a pigment. The preferred content of the ketone resin is 0.05 to 35% by weight based on the total amount of the composition.

Examples of the ketone resin used in the composition of the present invention include ketone resin K90 (manufactured by Arakawa Chemical Industry Co., Ltd.) and Hirac 110H (Hitachi Chemical Co., Ltd.).
Manufactured) and the like. These ketone resins may be used alone or in combination of two or more, and the compounding amount thereof is 0.05 to 35% by weight, preferably 0.2 to 25% by weight based on the total amount of the composition. Selected in a range. If the content is less than 0.05% by weight, the water resistance effect is insufficient, and if it exceeds 35% by weight, the viscosity of the ink becomes too high and the stability of the ink over time is impaired, which is not preferable.

The polyhydric alcohol used in the composition of the present invention is an organic solvent having two or more hydroxyl groups in the molecule, such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene. Glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butadiol, 1,5-pentanediol, hexylene glycol, octylene glycol, glycerin, diglycerin, polyglycerin, 1,2,6 -Hexanetriol and the like. Examples of the polyhydric alcohol derivative include derivatives of the polyhydric alcohol such as alkyl ether and fatty acid ester. These polyhydric alcohols or polyhydric alcohol derivatives may be used alone or in combination of two or more.

The dispersant used in the composition of the present invention may be any dispersant as long as it can be dissolved in a polyhydric alcohol or a polyhydric alcohol derivative.
Gum arabic, natural resins such as rosin, hydroxyethyl cellulose and its derivatives, semi-synthetic resins such as rosin derivatives, polyvinyl alcohol, polyvinylpyrrolidone,
Synthetic resins such as polyvinyl butyral, polyvinyl ether, styrene-maleic acid copolymer, styrene-acrylic acid copolymer and surfactants such as anionic surfactants, cationic surfactants and amphoteric surfactants are mentioned. May be used alone or in combination of two or more. The blending amount is 0.5 to 500% by weight based on the pigment.

The pigment used in the pigment ink composition of the present invention is not particularly limited, and any one of inorganic and organic pigments used in ordinary pigment ink compositions can be used. The compounding amount is selected in the range of 2 to 70% by weight based on the total amount of the composition. The usual pigment dispersion method in the pigment ink composition of the present invention can be obtained by, for example, dispersing and mixing by a method using a ball mill, a sand mill, a bead mill, a roll mill, a homomixer, a stirrer or ultrasonic waves.

The composition of the present invention may contain, if necessary, additives such as a preservative, a fungicide and a rust preventive, which are generally used.

[0011]

The pigment ink composition of the present invention is superior in dispersion stability of the pigment as compared with the conventional pigment ink composition, and has dramatically improved water resistance. Therefore, when the pigment ink composition of the present invention is used for a writing instrument, a stamp stand, a recorder, etc., the water resistance of the drawn line becomes very good. The reason why such an effect is exhibited is not clear, but the ketone resin contained in the pigment ink composition of the present invention forms a water-insoluble film by orienting on the ink surface of the drawn line, and the chemical properties of the ketone resin. This is considered to improve the adhesion of the ink to the writing surface such as paper.

[0012]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Example 1) Carbon black 15% by weight Polyvinylpyrrolidone 5 Ketone resin (Hilac 110H: manufactured by Hitachi Chemical Co., Ltd.) 5 Diethylene glycol monoethyl ether 15 Ethylene glycol 60 Component except carbon black in the above composition Were mixed and made uniform, and carbon black was added thereto and dispersed and mixed in a ball mill for 24 hours to obtain a pigment ink composition.

Comparative Example 1 A pigment ink composition was obtained in the same manner as in Example 1 except that the ketone resin was not added and ethylene glycol was 65% by weight.

(Example 2) Phthalocyanine blue 10% by weight Polyvinyl butyral 4 Ketone resin (ketone resin K90: manufactured by Arakawa Chemical Industry Co., Ltd.) 2 Ethylene glycol monomethyl ether 10 Diethylene glycol monobutyl ether 20 Propylene glycol monomethyl ether 54 Of the above compositions, Mix components other than phthalocyanine blue to make it uniform, add phthalocyanine blue to it,
It was dispersed in a ball mill for 24 hours to obtain a pigment ink composition.

Comparative Example 2 A pigment ink composition was obtained in the same manner as in Example 2 except that the ketone resin was not added and propylene glycol monomethyl ether was 56% by weight.
The pigment ink composition obtained as described above was filled in a commercially available writing instrument and written on a paper surface, and the water resistance of the writing line was tested. The results are shown in Table 1. The water resistance test was performed by immersing the written paper immediately after writing in water and observing the change in the drawn line at that time. When there was no change in the drawn line, it was marked with ○, when it changed slightly, it was marked with Δ, and when it changed, it was marked with x.

[0017]

[Table 1]

[0018]

INDUSTRIAL APPLICABILITY The present invention provides a pigment ink composition containing a polyhydric alcohol or a polyhydric alcohol derivative having improved water resistance as a solvent. Therefore, when this composition is used for a stamp stand, a recorder, etc., a drawn line having excellent water resistance can be obtained.

Claims (2)

[Claims] 1. A pigment ink composition comprising at least one or more solvents selected from polyhydric alcohols and polyhydric alcohol derivatives, a ketone resin, a dispersant and a pigment. 2. The pigment ink composition according to claim 1, wherein the ketone resin is contained in an amount of 0.05 to 35% by weight based on the total amount of the pigment ink composition.