PROCESS FOR THE PREPARATION OF MODIFIED PHENOL RESIN BINDERS AND THEIR USE IN THE PRODUCTION OF CHIP-BOARD PANELS

摘要

1. Process for producing modified phenolic resin bonding agents characterized by preparing as known per se phenol-formaldehyde resins with a viscosity of higher than 300 mPa.s (at 20 degrees C) with a solids content of 20 to 55% and adding to the viscous phenolic resin solutions 2 to 30 wt.-% urea, relative to the phenolic resin solution, the phenol-formaldehyde resins being prepared with as much alkali as is required to ensure that the modified resin solution resulting therefrom contains 2 to 12 wt.-% alkali (titrated, calculated as NaOH).