Sakura Color Products Corporation

Atsushi Sudo

Yasuyuki Yoshimura

Norimasa Kurihara

Norihiro Hirano

Isao Enjon

An erasable ink composition comprising water, a water-soluble organic solvent, and the following colorant, colorless resin particles and shear-thinning, viscosity-adjustment agent, characterized in that the colorless resin particles have a mean particle diameter smaller than that of the colorant and are contained in an amount larger than that of the colorant: (a) 3 to wt % (based on the whole ink) of colorless resin particles which are made of at least one resin selected from among acrylic resins, urethane resins, silicone resins and melamine resins and have a mean particle diameter of 0.10 to 10 &#x3bc;m, (b) 1 to 40 wt % (based on the whole ink) of a colorant having a mean particle diameter of 2 &#x3bc;m or above, and (c) 0.01 to 4 wt % (based on the whole ink) of a shear thinning, viscosity-adjustment agent.

Erasable ink composition

The main object is to provide a water-based ink composition which is not only superior in hiding power but also has satisfactory writing properties. This invention relates to a water-based ink composition comprising a powder consisting of inorganic particles comprising at least one of aluminum oxide, titanium dioxide and boron nitride and water.

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Osaka, Japan

Atsushi Sudo