JPH0819362B2 - Print ink composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a print ink composition. More specifically, it relates to a print ink composition having excellent storage stability.

(Prior Art) Conventionally, the printing ink used was an oil-based type or a neutral (water-in-oil emulsion type) type, but the odor / toxicity of the oil type and the instability of the neutral type emulsion Therefore, in recent years, a water-based printing ink containing a pigment, an alkali-soluble resin and a high boiling point organic solvent as a main component has been used.

(Problems to be solved by the invention) However, when the above print ink is stored for a long period of time, a so-called "water spring" phenomenon occurs in which a liquid substance in the ink is separated into an upper layer, which causes stirring and mixing during use. In order to prevent this "water spring" phenomenon, it is necessary to increase the proportion of powder such as pigments and fillers in the printing ink, or to use an alkali-soluble resin. Can be achieved by increasing the ratio of
When the proportion of powder is increased, the abrasion resistance of the printed print becomes weak and the durability of the work decreases.
Further, when the proportion of the resin is increased, the spinnability of the printing ink becomes strong, and when the ink is transferred to the wood block using a roller or the like, the ink once transferred to the wood block is pulled to the roller or the like. This causes unevenness on the woodblocks, which reduces the quality of the work. It prevents "water spouting", and at the same time, reduces the "rubbing resistance of the prints" and "excessive spinnability of the print inks". No solution was found that would not cause

(Means for Solving Problems) Therefore, in view of the above problems, the present inventors prevent the "water spring" phenomenon, have excellent storage stability, and lower the abrasion resistance of prints and the prints. The present invention was finally completed by conducting intensive research to obtain a print ink composition that does not cause excessive spinnability of the ink. The present invention is based on a pigment, an alkali-soluble resin, and a high-boiling aqueous solution. A printing ink composition comprising at least a water-soluble organic solvent, wherein the printing ink composition comprises hydroxyalkyl cellulose.

 Hereinafter, the present invention will be described in detail.

The pigment is used as a coloring material, and various conventionally known inorganic and organic pigments can be used. Specifically, carbon black, titanium oxide, red iron oxide, loess, Hansaello G, 10G, Burnt Sienna , Lake Red, Carmine 3B, 6B, Ultramarine Blue, Phthalocyanine Blue, Phthalocyanine Green and the like can be used alone or in combination, and the amount thereof is preferably 3 to 25% by weight based on the printing ink composition.

The alkali-soluble resin is used as a fixing agent and a color-developing agent for the above-mentioned pigment, and specifically, (meth) acrylic resin, styrene-acrylic resin, styrene-maleic acid resin, maleic acid resin, fumaric resin. An acid resin, a rosin-modified maleic acid resin, or the like can be used, and the amount thereof is preferably 5 to 20% by weight based on the aqueous printing ink composition.

The high boiling water-soluble organic solvent is used to prevent the printing ink composition from drying on the non-absorbing surface such as a kneading plate. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, etc. These glycols, glycerin, benzyl alcohol and the like can be used alone or in combination, and the amount thereof is preferably 10 to 70% by weight based on the printing ink composition.

The hydroxyalkyl cellulose, which is the essence of the present invention, is used as a “water spring” inhibitor, and specifically, hydroxyethyl cellulose, hydroxypropyl cellulose and the like are preferably used, and the amount thereof is used in the print ink composition. It is preferably 0.1 to 1.0% by weight.

In addition to the above components, if necessary, calcium carbonate,
Additives such as extenders such as barium sulfate, preservatives and fungicides, surfactants such as sodium alkylbenzenesulfonate, and penetration and drying accelerators such as lower aliphatic alcohols may be used as appropriate.

The print ink composition of the present invention can be easily obtained by mixing and dispersing the above components with a disperser such as a three-roll mill or a horizontal ball mill.

(Operation) The print ink composition according to the present invention is excellent in storage stability without "water spring", and also excellent in abrasion resistance of print.
In addition, it is speculated that the spinnability of the printing ink is appropriate for the following reasons. That is, since hydroxyalkyl cellulose is dissolved in the printing ink so as to form a three-dimensional network structure, the synergistic effect of this and the alkali-soluble resin suppresses the sedimentation of pigments and fillers over time. Therefore, it is considered that the "water spring" is prevented and the storage stability is improved. Further, since the print ink of the present invention does not increase the proportion of the powder, the abrasion resistance is not decreased, and further, the hydroxyalkyl is not observed. Even if cellulose is dissolved in a water-soluble organic solvent, it shows almost no spinnability, so it is considered that cellulose does not have excessive spinnability.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples.
"Parts" means "parts by weight".

Example 1 Carbon black 10 parts Precipitating barium sulfate 15 parts Rosin-modified maleic acid resin 10 parts Dimethylethanolamine 5 parts Glycerin 7 parts Triethylene glycol 28 parts Isopropyl alcohol 5 parts Hydroxypropylcellulose 0.5 parts Water 20 parts After premixing for 1 hour in a mixer, the mixture was passed through a 3-roll mill twice to obtain a black print ink composition.

Comparative Example 1 A black printing ink composition was obtained in the same manner as in Example 1 except that 0.5 part of hydroxypropylcellulose of Example 1 was replaced with glycerin.

Example 2 Carmine 6B 10 parts Precipitating barium sulfate 15 parts Rosin-modified maleic acid resin 10 parts Dimethylethanolamine 5 parts Ethylene glycol 20 parts Triethylene glycol 40 parts Hydroxyethyl cellulose 0.5 parts The above ingredients were placed in a lab mixer and premixed for 1 hour. After that, it was passed through a three-roll mill twice to obtain a red print ink composition.

Comparative Example 2 A red printing ink composition was obtained in the same manner as in Example 2 except that 0.5 part of hydroxyethyl cellulose of Example 2 was replaced with carboxymethyl cellulose.

(Effects of the Invention) Tests were performed on the above Examples 1 and 2 and Comparative Examples 1 and 2. The results are shown in the table.

Further, the print ink compositions obtained in Examples 1 and 2 were used to print prints, and in each case, the work was excellent in workability and the prints had good abrasion resistance.

As described in detail above, the print ink composition according to the present invention is excellent in storage stability without "water spring", and is also excellent in characteristics as other print inks. .

Further, it goes without saying that the present invention can be used not only as a printing ink but also as a normal paint.

Claims (1)

[Claims] 1. A printing ink composition comprising at least a pigment, an alkali-soluble resin, and a high-boiling point water-soluble organic solvent, wherein the printing ink composition contains hydroxyalkyl cellulose.