Infrared dyes soluble in methylene chloride and having an infrared absorption maximum above 1100 nm are disclosed which have minor discolouration in the visual spectrum. The infrared dyes are especially useful for producing multicolour laser marked security documents having reduced background discoloration and enhanced colour gamut.
本发明公开了可溶于
二氯甲烷并具有 1100 纳米以上红外吸收最大值的红外
染料,这些
染料在视觉光谱中具有轻微的变色。这种红外
染料特别适用于制作多色激光防伪文件,可减少背景变色,提高色域。