Ink composition for water-based ballpoint pens
AssigneeMitsubishi Pencil Company, Limited
InventorKosuke Ogura
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Abstract
An ink composition for a water-based ballpoint pen in which, even in a case of an ink composition for a water-based ballpoint pen using a colored resin particle containing a pigment, the phenomenon of skipped strokes does not occur and writing defects are less likely to occur when writing at a high writing angle or under a high load. An example of the ink composition for a water-based ballpoint pen according to the present embodiment includes an ink composition for a water-based ballpoint pen that contains at least a urethane-based colored resin particle containing a pigment and having an average particle size of 0.3 to 2 μm and a naphthalenesulfonic acid-formaldehyde condensate.
Claims9
A ballpoint pen comprising an ink composition, the ink composition comprising:
- a urethane-based colored resin particle;
- and
- a naphthalenesulfonic acid-formaldehyde condensate,
- wherein the urethane-based colored resin particle comprises carbon black and a synergist in a mass ratio of the synergist/the carbon black in a range of from 0.01 to 0.2,
- wherein the urethane-based colored resin particle has an average particle size in a range of from 0.5 to 2 μm, and
- wherein the naphthalenesulfonic acid-formaldehyde condensate is present in a range of 0.04 to 5.5 mass % relative to the total amount of the ink composition.
Dependencies are inferred from the claim text.