| 摘要 |
PURPOSE:To obtain a recording material possible in the reading from a visible region to a near infrared region by using a specific compound imparting a developed color image having strong absorption within a near infrared region and excellent in storage stability 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 is a hydrogen atom, a halogen atom or a dialkylamino group, R2 and R3 are a lower alkyl group, R4 is a hydrogen atom, a halogen atom, a lower or a dialkylamino group, formula III is a benzene ring or a naphthalene ring, B is a group represented by formula II wherein R5 and R6 are an alkylene group, R7 is a lower alkyl group and n is 0 - 4. The leuco dye represented by the formula is a white or light yellow crystal in usual and can be easily synthesized by the dehydro-condensation of a benzophenone derivative and a butadiene 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 70 - 1,000nm and said image can be sufficiently read by an image reading apparatus. |
