Adhesion composition comprising a formaldehyde-containing aminoplast resin and a catalysing compound

The invention relates to an adhesive composition comprising a formaldehyde-containing aminoplast resin and a catalysing compound, with the catalysing compound being an acid or is able to release an acid with a pKa lower than 4 and with the formaldehyde-containing aminoplast resin having a F/(NH2) 2 ratio lower than or equal to 1. The catalysing compound comprises at most 11 wt.% of an ammonium salt. The invention also relates to a process for the preparation of board material using the adhesive composition according to the invention and to the board material thus obtainable.