Process for the continuous preparation of solid phenol-formaldehyde resols

摘要

The invention relates to a process for the continuous preparation of phenol-formaldehyde resols. The aim of the invention is continuous preparation of PF resols using simple equipment and under constant process conditions. The object of the invention is the termination of the concentrating of the PF polycondensate in closed reaction vessels at a solids content of < 94%. According to the invention, the starting materials are condensed in multichamber reactors. The polycondensation is then completed on a circulating (continuous), heat-resistant belt, where first the PF polycondensate is concentrated to a solids content of > 94% by analysis thereof, and the polycondensation product is then cooled to a temperature below its melting point on the circulating, heat-resistant belt. The PF resols prepared according to the invention are used as bodywork and laminate resins.