Mitsubishi Pencil Kabushiki Kaisha

Hiroyuki Idogawa

Nobuatsu Watanabe

Kiyokazu Sakurai

Yong-Bo Chong

Atsushi Iwasa

Yasuaki Ogiwara

Atsushi Wakata

Oil-base pigment ink composition for writing tools

Provided is a stable water base ink composition which has a sufficiently high concentration as ink for an ink jet-recording apparatus and writing instruments and prevents the recorded images and the written characters from being blurred or disappearing with water and sweat and which has such an excellent light fastness that the images and the characters do not deteriorate over a long period of time and does not cause a change in physical properties and precipitates. A water base dispersion liquid containing colored resin fine particles is prepared by emulsion-polymerizing a vinyl monomer in the presence of a hydrophobic dye and then diluted with water or a water soluble organic solvent, whereby the water base ink composition is produced.

Water base ink composition

Provided is a colored resin fine particle water base dispersion liquid which can be a base material for an ink causing no precipitates and having storage stability. Further provided is a water base ink composition for an ink jet recording apparatus or a water base ink composition for a writing tool capable of providing recorded images or written characters and drawn lines which are clear and neither are blurred nor disappear due to water and sweat and which are so excellent in light fastness that they are not deteriorated over a long period of time, wherein the colored resin fine particle water base dispersion liquid is produced by mixing a water soluble basic dye with a mixed vinyl monomer containing a vinyl monomer having an acid functional group and emulsion-copolymerizing the above mixture.

Colored resin fine particle water base dispersion liquid for water base

The present invention provides a recording material containing a carbonaceous powder whose surfaces are modified with a fluorine gas. Even when the recording material of the present invention is stored for a long period of time, a carbonaceous powder such as a graphite powder or carbon black neither coheres nor precipitates. For example, even if the recording material of the present invention is used in a felt pen or a ball-point pen, the carbonaceous powder does not cohere in the container or the pen point, and therefore any clogging does not occur in the pen point and good writing is possible.

Recording material containing carbonaceous powder whose surface is

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Urawa, Japan

Hiroyuki Idogawa