US 12,441,899 B2
Ink composition for water-based ballpoint pen
Akiko Hirayama, Shinagawa-ku (JP); and Kousuke Ogura, Shinagawa-ku (JP)
Assigned to MITSUBISHI PENCIL COMPANY, LIMITED, Shinagawa-ku (JP)
Appl. No. 17/759,825
Filed by MITSUBISHI PENCIL COMPANY, LIMITED, Shinagawa-ku (JP)
PCT Filed Jan. 30, 2020, PCT No. PCT/JP2020/003464
§ 371(c)(1), (2) Date Jul. 29, 2022,
PCT Pub. No. WO2021/152779, PCT Pub. Date Aug. 5, 2021.
Prior Publication US 2023/0073595 A1, Mar. 9, 2023
Int. Cl. C09D 11/18 (2006.01); B43K 7/02 (2006.01); C09D 11/17 (2014.01)
CPC C09D 11/18 (2013.01) [B43K 7/02 (2013.01); C09D 11/17 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A water-based ballpoint pen, comprising:
a ballpoint pen tip having a ball with a ball diameter of 0.5 mm or less; and
an ink composition suitable for a water-based ballpoint pen,
wherein the ink composition comprises an aluminum pigment, having an average particle size in a range of from 5 to 20 μm, in a range of from 0.1 to 20 mass % and solid urethane particles, having an average particle size in a range of from 0.3 to 10 μm, in a range of from 8 to 25 mass %.