Water-based ink composition for fine pointed ballpoint pen and fine pointed ballpoint pen

Abstract

Provided is a water-based ink composition for a fine pointed ballpoint pen characterized by blending an ink composition comprising at least water, a colorant and a water soluble solvent with at least one kind of ultra fine particles selected from the group consisting of alumina, titanium oxide, silica, silicon carbide and tungsten carbide each having an average particle diameter of less than 0.1 [mu]m, wherein a blending amount of the ultra fine particles is 0.002 to 2 % by weight based on the ink composition, particularly preferably an ink composition having a viscosity of 50 to 2000 mPa.s (25 DEG C) which is measured at 1 rpm by means of a corn and plate type rotational viscometer (1 DEG 34'R24 corn). Further, provided is a fine pointed ballpoint pen having a ball of a diameter of 0.4 mm or less, filled with the water-based ink composition described above.

Description

technical field [0001] The present invention relates to a water-based ink composition for ballpoint pens, in particular to a water-based ink composition which has excellent A water-based ink composition with excellent ball mount abrasion resistance, line quality, ink drainage characteristics, and excellent stability over time; and a fine-tip ballpoint pen. Background technique [0002] When writing with a ball-point pen, ink is delivered to the writing position by the rotation of the ball, and there has been a problem so far that the parts that hold the ball and come into contact with it inside the ball-point pen point (ball-housing seat) ) wears as the ball rotates, so that the ink discharge port becomes clogged, or the caulking part holding the ball comes into contact with the paper surface, causing poor writing (such as lack of ink and writing failure). Therefore, attempts have been made to add water-soluble cutting oils and surfactants to ballpoint...

AI Technical Summary

Problems solved by technology

[0002] When writing with a ball-point pen, ink is delivered to the writing position by the rotation of the ball, and there has been a problem so far that the parts that hold the ball and come into contact with it inside the ball-point pen point (ball-housing seat) ) wears as the ball rotates, so that the ink discharge port becomes clogged, or the caulking part holding the ball comes into contact with the paper surface, causing poor writing (such as lack of ink and writing failure)

Therefore, it is easy to cause serious inconvenience that it is impossible to write before the ink is used up, and there is a big problem in the design of the fine tip ballpoint pen.

Specifically, in the case of a fine-tip ballpoint pen having a ball diameter of 0.4 mm or less, the frictional resistance further increases, thereby causing significant wear of the mount

In addition to this, it is difficult to make the ball rotate smoothly, so there have been serious problems of poor writing feeling and lower quality of marking due to directional defects and broken lines

[0004] In addition, due to the small area of ​​the ink discharge port, the ink discharge characteristics of fine-tip ballpoint pens with small ball diameters tend to deteriorate, so that it is usually necessary to reduce the viscosity of the ink

However, when fine particles are mixed in ink, particles with a large specific gravity settle down over time, causing serious problems such as poor writing feeling, poor ink discharge characteristics, and clogging caused by settling. Poorly written, so this needs to be addressed early on

[0005] Therefore, in a fine-tip ballpoint pen having a ball diameter of, for example, 0.5 mm or less, only adding fine particles having a particle diameter of 0.1 micrometer or more and 30 micrometers or less cannot satisfactorily suppress wear of the mount, and scratches occur. Serious problems of reduced line quality, poor writing feeling, poor ink discharge characteristics, and poor writing due to clogging due to sedimentation