Process modification involving strong-acid step in urea-formaldehyde resin preparation


  • Dicky Dermawan Department of Chemical Engineering Institut Teknologi Nasional Bandung Indonesia
  • Lucky William Kusnadi Department of Chemical Engineering Institut Teknologi Nasional Bandung Indonesia
  • Jemmy Lesmana Department of Chemical Engineering Institut Teknologi Nasional Bandung Indonesia



UF resin, Plywood, Alkaline – Acid Process, Strong Acid Step


Urea-formaldehyde (UF) resin adhesive for wood-based panel industries are commonly manufactured using conventional alkaline-acid process. This paper reports a process modification of a conventional UF resin preparation by incorporating a strong-acid step, involving simultaneous methylolation and condensation reactions at very low pH at the beginning of the processing step. The experiment showed that this additional step should be carried out at short duration and at high enough temperature in order to avoid gelation or separation problems. In order to control temperature rise caused by the exothermic nature of the reactions, the modified process requires a higher initial formaldehyde-to-urea (F/U) molar ratio compared to the original. For the same reason, the first urea should be fed incrementally to ensure high F/U ratio at any time during the strong acid step. Using regular formalin concentration as raw material at the same F/U molar ratio, the modified resin showed lower free formaldehyde content thus have lower reactivity in comparison to those of the original. However, when the same procedure was applied using higher formaldehyde concentration at higher solid content, the produced resin showed comparable free formaldehyde content and shorter gelation time. Application test for making plywood showed that the modified process gave a very significant improvement in both the internal bonding strength and formaldehyde emission.

Author Biographies

Dicky Dermawan, Department of Chemical Engineering Institut Teknologi Nasional Bandung Indonesia

Master degree in Chemical Engineering. Research interest in Chemical Product Development. Works as academic staff at Itenas for almost 23 years now.

Lucky William Kusnadi, Department of Chemical Engineering Institut Teknologi Nasional Bandung Indonesia

former student

Jemmy Lesmana, Department of Chemical Engineering Institut Teknologi Nasional Bandung Indonesia

former student


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