Method for marking materials, e.g. pharmaceuticals, packaging or bank notes, uses coded polymer micro-particles containing dye and-or doped nano-particles, or aggregates of different groups of such micro-particles

摘要

Coded micro-particles for marking materials are obtained by polymerisation of unsaturated monomers in presence of dyes and/or doped nano-particles, and/or by agglomeration of at least two groups of microparticles which differ in their absorption, emission and/or scattering of electromagnetic radiation, to give aggregates with a particle diameter of 300 nm to 500 microns. A method for marking materials with coded micro-particles (I), in which (I) are obtained by (i) reversed water-in-oil suspension polymerisation of water-soluble mono-unsaturated monomer(s) (IIa) in presence of poly-unsaturated comonomer(s) (III) using doped nano-particles (IV) as the suspension medium, (ii) emulsion polymerisation of water-insoluble mono-unsaturated monomers (IIb) with 0-10 wt% (III) using (IV) as emulsifier for stabilising the disperse phase, (iii) polymerisation of (II) with a copolymerisable dye containing an ethylenic double bond, optionally followed by agglomeration of the resulting particles, or (iv) agglomeration of at least two groups of micro-particles which differ in their absorption, emission and/or scattering of electromagnetic radiation, to give aggregates with an average particle diameter of 300 nm to 500 microns. An independent claim is also included for materials containing coded (I) for the purposes of marking.