| abstract |
A heat-sensitive recording material is described which contains at least one substance from the group 4,4ʹ-dihydroxydiphenyl sulfone, 2,4ʹ-dihydroxydiphenyl sulfone and bis- (3-tert-butyl-4-hydroxy-6-methylphenyl) sulfone and one in the color development layer contains special fluorene leuco dye. The recording material according to the invention has superior resistance to the effects of light, climate and oils, and better optical readability in the near infrared range. |