PROCESS FOR PREPARING UREA-FORMALDEHYDE RESIN SOLUTIONS TO BE HARDENED

摘要

A method for the preparation of solutions of hardenable urea-formaldehyde resins which are suitable for impregnating paper supports used for coating wood-based panels wherein urea and formaldehyde are first mixed in specific mole ratios and reacted for a period of time to a given viscosity, an aminosulfonic acid is then added and the pH is controlled with ammonia to further react the mixture and finally, additional ammonia and urea are added to produce the final viscosity product wherein a portion of the initial urea is replaced with a melamine which results in significant improvements in the temperature and pH control of the process.