Alkaline condensed urea - - - phenol formaldehyde resin solution, to a process for their preparation and their use in the production of particle boards

摘要

An alkali-condensed urea-phenol-formaldehyde resin solution having a solids content of from 38 to 60 % by weight has an improved shelf life and is characterised in that it contains (a) sulphite and/or hydroxymethanesulphinate in a concentration of from 0.2 to 3 % by weight, calculated as SO32- or sulphinic acid radical, and (b) dimethylolurea and/or trimethylolurea in a concentration of from 0 to 5 % by weight, in each case based on the total weight of the resin solution.