| abstract |
A heat sensitive coating composition comprises a colour former, 1,5-diisopropylnaphthalene as sensitizer and a colour developer, wherein the colour developer is selected from the group consisting of N-(p-toluenesulfonyl)-N'-(3-p-toluenesulfonyloxy)phenyl) urea, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone and bis(3-allyl-4-hydroxyphenyl)sulfone. The colour former is preferably a fluoran. |