All PU- and TPU soles are injection-molded, and the molds are prepared with a mold-release agent
before injection takes place. This chemical is often transferred to the finished soles, which of course
hampers the bonding process. Grinding would remove it from the surface, but that is not practicable
with unit soles. Therefore: Clean flat TPU soles or PU/TPU unit soles with the new Renia – Cleaner
for PU/TPU before bonding – apply the product to a rag and scrub the soles thoroughly in order to
remove any leftover mold release agents. Let the Cleaner dry for at least 10-15 minutes when working
with Primer for PU/TPU as the next step, or leave for at least 60 minutes when bonding with a PUbased adhesive straight after cleaning.
Priming and bonding
CR-based contact adhesives are generally not suitable for bonding compact PU and TPU by
themselves. PU-based adhesives such as Renia – Syntic-TOTAL work well on PU, but have difficulties
on TPU as well. The solution for this problem: Coat the cleaned (see above) compact TPU soles or
PU/TPU unit soles with the new Renia – Primer for PU/TPU and let that dry for at least 60 minutes.
The primed material can then be bonded with Renia- and Siema PU-based adhesives (SynticTOTAL, Siemaplast) as well as Renia – Colle de Cologne and all Renia/Siema – CR-based
adhesives. The best results are achieved by using PU-based adhesives or Colle de Cologne. Please
keep in mind: Unit soles require sufficient pressure, also from the side!
Renia Cleaner Primer for PU/TPU 250ml - 53V201