LOW ADDITION OF MELAMINE SALTS FOR IMPROVED UF ADHESIVES WATER RESISTANCE

Melamine/acid salts such as melamine acetate, melamine formate and mel amine oxalate, function both as efficient hidden hardeners of UF resin s for plywood as well as upgrading the performance of simple UF resins for plywood through approximately 10% by mass melamine grafting to yi eld comparable strength durability of premanufactured MUF resins of 30 %-40% melamine mass content, hence of resins of much higher mass conte nt of melamine. The system works by simple addition of a melamine salt in the UF gluemix eliminating the need to premanufacture a MUF resin. The effectiveness of melamine grafting in the glue-mix and during hot pressing has been found to depend from the relative solubility of the melamine salt which depends from both the acid strength of the acid a s well as the number of acid functions in the salt. The reasons why tr aditional, premanufactured MUF resins waste 2/3 or more of the melamin e used in them, and why the system presented is so much more effective by not wasting melamine are presented and discussed.