Diester of bisphenol fluorene compounds and thermochromic pigment compositions comprising the same

Abstract

There is a compound represented by the following formula (I): in which R1 and R2, identical or different, represent a C2-C30 alkyl group, a C2-C30 alkenyl group, a C2-C30 alkynyl group, or a C2-C30 alkoxy group, the alkyl, alkenyl, alkynyl, or alkoxy groups being optionally substituted with at least one hydroxy, halogen, amino, C1-C8 alkyl, or C1-C8 alkoxy group, as a temperature change regulating agent in a thermochromic ink composition. There also are thermochromic pigment microcapsules having a compound of formula (I) according to the disclosure, to ink compositions having such thermochromic pigment microcapsules, and to writing instruments comprising such ink compositions.

Dependencies are inferred from the claim text.