| abstract |
The present invention relates to microparticle compositions comprising an organic IR absorbing pigment having a main absorption maximum in the range from 750 to 1100 nm. The invention also relates to a process for producing said microparticle compositions and to their use in a printing ink, in particular in a printing ink, which is suitable for producing a security feature or a security document. The microparticles of the pigment composition contain the organic IR absorbing pigment as solid particles, which are surrounded by or embedded in an aminoplast polymer, which is a polycondensation product of one or more amino compounds and one or more aldehydes. The microparticle based pigment composition is characterized by a volume based particle size distribution, as determined by static light scattering according to ISO 13320:2009 EN, having a D(4,3) value in the range from 1.0 to 15.0 µm. |