Bonding, e.g. wood laminates, with thermosetting adhesive - by separately applying aminoplast mixed with buffer and acid hardener, to lengthen closed waiting time (NO 25.4.77)

摘要

Closed wating time in bonding components with HCHO-based aminoplast thermosetting adhesives, is lengthened by mixing the resin component with a buffer cpd. for the separately added hardener, which contains an acid or an acid-dissociating cpds. Process is used for bonding or laminating wood and boards, e.g. for doors. Closed waiting time can be lengthened, e.g. from 3 to >9 min., without increasing hardening time. The resin component is pref. applied to one of the surfaces to be bonded, while the hardenr is applied as soln. to the other surface. The separately added hardener contains or releases an acid having acid dissociation const. pKa 2.5 at 25 degrees C, e.g. maleic acid, CCl3COOH or inorganic acids. Hardening takes place in a hot press.