Die Eigenschaften formaldehydarmer HF-Leimharze und daraus hergestellter Holzspanplatten. 1. Mitteilung: Einfluß des Molverhältnisses auf die Eigenschaften der Rohleimharze

The influence of the molar ratio of urea: formaldehyde on the chemical, physical, and technological properties of the uncondensed resins was investigated. The molar ratio of the industrial resins varied between 1:2,1 and 1:1,2. Viscosity, water compatibility, stability and free formaldehyde content of the uncondensed resins are influenced significantly by the molar ratio. Using common ammonium salt hardeners, the hardening reaction decreased considerably for resins with low formaldehyde content