| 摘要 |
PURPOSE:To obtain a recording material imparting a developed color image, which has strong absorption within a near infrared region and shows a hue nearer to black in the absorption within a visible region, and reduced in the yellowing of a background part due to light by using a compound represented by a specific chemical structural formula as at least one kind of a leuco dye. CONSTITUTION:At least one kind of a leuco dye composed of a compound represented by formula I is used in a recording material. In the formula, R1 and R2 are a lower alkyl group, a cycloalkyl group, an aralkyl group or an aryl group and, further, may be mutually bonded to form a ring or bonded through -O- to form a morpholino ring, R2 is a hydrogen atom, a lower alkyl group, an alkoxy group or an aralkyloxy group, R4 and R5 are a lower alkyl group and R6 is a hydrogen atom, a lower alkyl group, an alkoxy group or a halogen atom. The leuco dye represented by the formula I is a white - faint yellow crystal in usual and can be easily synthesized by the dehydro- condensation of a ketone derivative and an ethylene derivative in the presence of a dehydro-condensation agent. The recording material using this leuco dye imparts a developed color image having strong absorption over a range of 700 - 900nm and said image can be sufficiently read by an image reading apparatus. |
