Phenol urea/melamine formaldehyde copolymers, method for the production thereof and use of the same

The invention relates to phenol urea/melamine formaldehyde copolymers which can be obtained through the condensation of an aqueous precondensate of phenol and/or phenol derivatives with an aqueous precondensate of urea and/or urea derivatives and/or melamine and/or melamine derivatives and formaldehyde in the presence of an anionic ion exchanger and a cationic ion exchanger. Thereby in the first step urea and phenol are reacted with formaldehyde in separate reactions. The reaction is regulated by time, pH value and temperature such that only methylol ureas or methylol phenols are formed. In the next step the two reaction mixtures are combined and come into contact with the immobilized ion exchanger (which can also be used catalytically).