Adhesive system

摘要

The invention concerns an adhesive system comprising (a) a resin component comprising a urea based amino resin having an F/NH2 ratio from 0.3 to 0.65; (b) a hardener component comprising at least one acid, acid generating salt or acidic salt; and, (c) an aqueous polymer dispersion; wherein the adhesive system comprises no or less than 0.9 wt % of urea, based on the weight of the entire adhesive system, in addition to any urea present in the urea based amino resin. The invention further concerns a method of producing a wood based product, wood based products obtainable thereby and use of the adhesive system.

主权项

1. An adhesive system comprising
a. a resin component comprising a urea based amino resin having an F/NH2 ratio from 0.3 to 0.65, the F/NH2 ratio being defined as the molar ratio between formaldehyde and the sum of all nitrogen atoms except those in the ring structure of aromatic groups, and wherein the urea based amino resin is a condensation product of formaldehyde and at least one compound carrying —NH2 or —NH groups in which urea constitutes from 75 to 100 wt % of said at least one compound carrying —NH2 or —NH groups; b. a hardener component comprising at least one acid, acid generating salt or acidic salt; and, c. an aqueous dispersion of at least one polymer comprising at least one of polyvinyl acetate (PVAc) and poly ethylene vinylacetate (EVA);wherein the adhesive system comprises no or less than 0.9 wt % of urea, based on the weight of the entire adhesive system, in addition to any urea present in the urea based amino resin.