Limits and innovation in poly(vinyl acetate) water resistant D3 glues

Present work describes the chemistry at the basis of standard PVAc-D3 products, explaining the role of the cross-linking agent and also giving some insights into the function of Al3+. Furthermore, the possible role played by these compounds in determining some inconveniences, such as formaldehyde release during time, glueline colouring, acidic pH, indirect staining of wood and equipment corrosion, is also described: it is shown how formaldehyde emissions are mostly related to the curing agent, and that both wood staining and glueline discoloration are related to the presence of Al3+. Finally, we showed how understanding those mechanisms constituted the basis for the development of a new generation of PVAc-D3 glues characterised by a good adhesion to wood surfaces, and exhibiting neither corrosive nor chromatic alteration evidences as well as absence of formaldehyde, thus allowing the compliance to the ultimate strictest legislations in terms of formaldehyde emission (CARB, E1-plus) in wood products.