A phtalide compound and a near infrared absorber and a recording material each comprising the same compound.

摘要

A phthalide compound of general formula (I) and a near infrared absorber and a recording material each utilizing the phthalide compound are disclosed. <CHEM> wherein ring A represents a substituent group of the following formula <CHEM> where R1 represents hydrogen, alkyl, alkoxy or halogen; n represents an integer of 1-3; ring B represents a defined aromatic ring; R2 represents alkyl or aryl; R3 represents alkyl; R4 and R5 independently represent alkyl or unsubstituted or substituted phenyl; R6 represents hydrogen, alkyl or alkoxy. The near infrared absorber and the recorded image on the recording material absorb strongly the near infrared region with no appreciable absorption in the visible region of the spectrum. The near infrared absorber is colorless or pale in color and yet highly capable of absorbing near infrared radiation. The recorded image on the recording material can hardly be read with the eye but can be read with the OCR. Moreover, the effect on the developed shade of any concomitant color former in a recording material is minimal.