| 摘要 |
NEW MATERIAL:Fluoran derivatives of formula I wherein R<1>, R<2> are each a 1- 4C lower alkyl. EXAMPLE:2-(4-Acetylphenyl)amino-6-N-methyl-N-4'-n-butylphenylaminofluo ran. USE:They are used as a heat-sensitive color coupling component for leuco thermal recording materials and gives thermal recording materials which exhibits little ground color formation, has a high color density and a low initial color forming temp. and is excellent in initial rise of color formation. PREPARATION:A diphenylamine compd. of formula II (wherein R is H, lower alkyl) is reacted with a benzophenone compd. in the presence of a condensing agent such as conc. sulfuric acid. The reaction product is separated and purified by filtration, extraction, recrystallization, etc. to obtain the fluoran derivative of formula I . |
