Laser-effected darkening in TPEs with TiO2 additives

Investigations were carried out for laser-effected darkening and damage-free laser marking on thermoplastic elastomers (TPEs). Titanium dioxide (TiO₂) was studied as the laser-sensitive additive to the TPEs for its role in enhancing laser marking contrast and its effect on the TPE properties. Laser beam characteristics, processing variables and percentage loading of TiO₂ in the TPEs were found to have significant effect on the marking contrast. Surface damage-free and high contrast marking have been achieved with short pulse UV lasers. The laser-effected darkening was found to penetrate into the material in the order of a few tens of microns. XPS analysis was carried out to understand the laser-effected darkening mechanism. Potential applications of the technique are highlighted.