	US 12,473,445 B2
	Ink composition for aqueous ballpoint pens
Kosuke Ogura, Shinagawa-ku (JP)
Assigned to MITSUBISHI PENCIL COMPANY, LIMITED, Shinagawa-ku (JP)
Appl. No. 17/771,757
Filed by MITSUBISHI PENCIL COMPANY, LIMITED, Shinagawa-ku (JP)
PCT Filed Oct. 21, 2020, PCT No. PCT/JP2020/039585 § 371(c)(1), (2) Date Apr. 25, 2022, PCT Pub. No. WO2021/085270, PCT Pub. Date May 6, 2021.
Claims priority of application No. 2019-196109 (JP), filed on Oct. 29, 2019.
Prior Publication US 2022/0411651 A1, Dec. 29, 2022
Int. Cl. C09D 11/18 (2006.01); C09D 11/17 (2014.01)

CPC C09D 11/18 (2013.01) [C09D 11/17 (2013.01)]

20 Claims

1. An aqueous ink composition suitable for a writing instrument, the composition comprising:

colored resin particles (A) encapsulating a pigment (a); and

non-colored resin particles (B) comprising no pigment,

wherein the pigment (a) is carbon black, encapsulated together with a synergist comprising an acidic functional group in the colored resin particles (A), and

wherein a (B)/(A) mass content ratio of the non-colored resin particles (B) to the colored resin particles (A) is in a range of from 0.05 to 1.0.