Industrial Melamine/Urea Formaldehyde Resins - Effects of Aging, and Production Consistency

This work looks into the process of aging of industrial water-based UF/MUF adhesives, produced on-site at Fantoni SpA. It aims to understand the chemical changes that occur within typical period of storage (pot life), up to ~20 days. To that end, change in chemical composition of the constituent molecules was investigated with FTIR; which found that aging process led to formation of methylene-ether bridges, following a somewhat similar pathway to curing at 90ºC. GPC investigation yielded ambiguous results, proving to be a demanding technique for monitoring aging process. Insight into kinetics of the process with DSC measurements, without and with the hardener (ammonia sulfate), showed that addition of the hardener made melamine-free adhesive reap higher benefits, as well as indicating that melamine-containing adhesive is highly susceptible to aging, slowing its subsequent curing kinetics.