Abstract: The present invention relates to Microsphere comprising a core and a shell, in which the core comprises a polymer and at least two laser light absorber. The particle size of the microsphere is for example between 50 nm and 50 micron and preferably between 100 nm and 10 micron. The core comprises a thermoplastic polymer, the shell comprises a compatibilizer. The laser light absorbers are chosen from oxides, hydroxides, sulphides, sulphates and phosphates of metals such as copper, bismuth, tin, aluminum, zinc, silver, titanium, antimony, manganese, iron, nickel, barium, gallium, germanium, arsenic and chromium and combinations of two or more of these metals, laser light absorbing (in)organic dyes or metaloxide coated flakes. The invention further relates to the use of the microsphere as a laser marking additive and to a process for the production of the microsphere by reactive extrusion.

Abstract: The present invention relates to Microsphere comprising a core and a shell, in which the core comprises a polymer and at least two laser light absorber. The particle size of the microsphere is for example between 50 nm and 50 micron and preferably between 100 nm and 10 micron. The core comprises a thermoplastic polymer, the shell comprises a compatibilizer. The laser light absorbers are chosen from oxides, hydroxides, sulphides, sulphates and phosphates of metals such as copper, bismuth, tin, aluminum, zinc, silver, titanium, antimony, manganese, iron, nickel, barium, gallium, germanium, arsenic and chromium and combinations of two or more of these metals, laser light absorbing (in)organic dyes or metaloxide coated flakes. The invention further relates to the use of the microsphere as a laser marking additive and to a process for the production of the microsphere by reactive extrusion.