Ink composition and components thereof

摘要

PCT No. PCT/GB90/02033 Sec. 371 Date Jul. 24, 1992 Sec. 102(e) Date Jul. 24, 1992 PCT Filed Dec. 28, 1990 PCT Pub. No. WO91/11492 PCT Pub. Date Aug. 8, 1991.Raman-active compounds such as polydiacetylenes are provided in the form of particles whose maximum dimension is 40 mu m. They can be formulated into inks, for the purpose of printing on security documents which are thus readily capable of authentication.