| 摘要 |
A color-developing sheet for pressure-sensitive recording sheets, said sheet comprising as a color-developing agent at least one 2,2'-bisphenolsulfone nickel salt selected from compounds of the following formula <IMAGE> (II) and <IMAGE> wherein R3, R4, R5, R6, R7 and R8 are identical or different, and represent a hydrogen atom, a halogen atom, an alkyl group containing 1 to 10 carbon atoms, a cycloalkyl group containing 3 to 10 carbon atoms, an aralkyl group containing 7 to 11 carbon atoms, or a phenyl group, or a mixture of at least one 2,2'-bisphenolsulfone nickel salt of the above formulae (II) and (III) and at least one 2,2'-bisphenolsulfone zinc salt of the following formula <IMAGE> (I) wherein R1 and R2 are the same as R3 through R8 defined above. |
