Sakura Color Products Corporation

Norihiro Hirano

Yasuyuki Yoshimura

Norimasa Kurihara

Atsushi Sudo

Hiroshi Inoue

Hidetoshi Fukuo

Naoshi Murata

Satoshi Maruyama

Shoko Matsumoto

Keiko Nakamura

Kaoru Matsumoto

Kenichi Shibuya

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

A polychromic ink composition depending on viewing angle comprises 0.5 to 40% by weight of cholesteric liquid crystal polymer particles whose maximum particle diameter is 1 to 200 &mgr;m, 1.0 to 30.0% by weight of binder resins, 0.05 to 20% by weight of pigments with a deep-colored coloring matter whose average particle diameter is 0.01 to 0.5 &mgr;m, 0.01 to 5.0% by weight of a shear-thinning property imparting agent, and water with respect to the total amount of the ink composition.

Polychromic ink composition depending on viewing angle

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.

Aqueous ink composition

A water base erasable ink composition for use in marking pens which comprises:

Water base erasable ink compositions

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Higashiosaka, Japan

Norihiro Hirano