This graft is then mixed with a catalyst masterbatch, typically in the ratio 95:5. This catalyst masterbatch is usually based on a tin catalyst such as di-butyl tin dilaurate (DBTDL) in a polymer carrier. This can either be pre-mixed with the graft or dosed into the extruder hopper along with the graft. This mixture is extruded to make the pipe or cable and the curing reaction occurs after the extrusion.
The first step in the curing process is that water must be introduced to hydrolyse the graft to replace the alcohol groups on the ends of the side chains.