Excirad 172 lamps can be used for post-cross-linking of cured acrylate coatings.  Photons with energies of 7.2 eV, as they are generated by excimer sources as Excirad 172 are strongly absorbed in a polyacrylate matrix.  They reach penetration depths of a several 10 to a several 100 nm in polyacrylates.   Radiation-initiated primary processes are triggered by electronic excitation of molecular states in the polymer molecule, which leads to the generation of polymer radicals.  Polymer radicals lead through recombination to crosslinking, i.e. to an increase of the molecular weight and a reduction of the free volume in the polymer.

As a result of the post-cross-linking we can observe:

• an increased microhardness
• an improved chemical resistance
• an increased surface energy (in combination with oxygen)

Patent pending