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.
把可溶于
氯化亚
甲烷且红外吸收峰值在1100纳米以上的红外
染料公开,这些
染料在可见光谱中有轻微变色。这些红外
染料特别适用于生产多色激光标记的安全文件,以减少背景变色并增强色彩范围。