US 12,246,549 B2
Thermosensitive recording medium
Kenji Hirai, Tokyo (JP); Kentaro Kawasaki, Tokyo (JP); Yuka Murata, Tokyo (JP); and Yoshimi Midorikawa, Tokyo (JP)
Assigned to Nippon Paper Industries Co., Ltd., (JP)
Appl. No. 17/802,599
Filed by Nippon Paper Industries Co., Ltd., Tokyo (JP)
PCT Filed Feb. 8, 2021, PCT No. PCT/JP2021/004529
§ 371(c)(1), (2) Date Aug. 26, 2022,
PCT Pub. No. WO2021/171983, PCT Pub. Date Sep. 2, 2021.
Claims priority of application No. 2020-033448 (JP), filed on Feb. 28, 2020.
Prior Publication US 2023/0144275 A1, May 11, 2023
Int. Cl. B41M 5/333 (2006.01); B41M 5/323 (2006.01); B41M 5/42 (2006.01)
CPC B41M 5/3333 (2013.01) [B41M 5/323 (2013.01); B41M 5/42 (2013.01); B41M 2205/04 (2013.01); B41M 2205/40 (2013.01)] 5 Claims
 
1. A thermosensitive recording medium having a thermosensitive recording layer comprising a colorless or pale colored electron donating leuco dye and an electron accepting color developing agent on a substrate,
wherein the thermosensitive recording layer contains at least two kinds of urea compounds as the electron accepting color developing agents,
the first urea compound being represented by one compound selected from the group consisting of N, N′-di-[3-(p-toluenesulfonyloxy) phenyl] urea, N, N′-di-[3-(o-toluenesulfonyloxy) phenyl]urea, N, N′-di-[3-(benzenesulfonyloxy) phenyl]urea, N, N′-di-[3-(mesitylene sulfonyloxy) phenyl urea, N, N′-di-3-(2-naphthalenesulfonyloxy) phenyl] urea, N, N′-di-[3-(p-methoxybenzenesulfonyloxy) phenyl] urea, N, N′-di-[3-(benzylsulfonyloxy) phenyl] urea, N, N′-di-[3-(ethanesulfonyloxy) phenyl] urea, N, N′-di-[4-(p-toluenesulfonyloxy) phenyl] urea, and N, N′-di-[4-(benzenesulfonyloxy) phenyl] urea, and
the second urea compound being a compound represented by the following general formula 6 or 7,

OG Complex Work Unit Chemistry

OG Complex Work Unit Chemistry
and
wherein a content of the second urea compound is from 1.0 to 30.0 parts by weight per 1.0 part by weight of the first urea compound, in the thermosensitive recording layer.