RELEASE OF POLYMER GEL FROM POLYMERIZATION BELT IN PRODUCTION OF WATER-ABSORBENT POLYMER PARTICLES

摘要

The invention generally relates to a process for the preparation of water-absorbent polymer particles, comprising the process steps of (i) preparing an aqueous monomer solution comprising at least one partially neutralized, monoethylenically unsaturated monomer bearing carboxylic acid groups (α1) and at least one crosslinker (α3); (ii) optionally adding fine particles of a water-absorbent polymer to the aqueous monomer solution; (iii) adding a polymerization initiator or a at least one component of a polymerization initiator system that comprises two or more components to the aqueous monomer solution; (iv) optionally decreasing the oxygen content of the aqueous monomer solution; (v) charging the aqueous monomer solution onto a belt of a polymerization belt reactor; (vi) polymerizing the at least one monomer in the aqueous monomer solution on the belt, thereby obtaining a polymer gel; (vii) discharging the polymer gel from the belt and comminuting the polymer gel; (viii) drying the comminuted polymer gel; (ix) grinding the dried polymer gel thereby obtaining water-absorbent polymer particles; (x) sizing the grinded water-absorbent polymer particles; and (xi) optionally treating the surface of the grinded and sized water-absorbent polymer particles; wherein in process step (vi) or (vii) or both a releasing agent is applied to at least a part of the belt.