Abstract

The present invention relates to an environmentally sound method for the production of urea-melamine-formaldehyde resin characterized by the stagewise condensation of formaldehyde with urea and the subsequent co-condensation of the obtained prepolymer with melamine. Urea- formaldehyde concentrate may be used as formaldehyde feed for production of the urea-melamine-formaldehyde resin. The condensation with urea is performed in three stages by introducing urea batchwise. The process requires media with alternating acidity and heating supply. An acid condensation stage is part of the process. Deionized water may be used as viscosity regulator. Borax may be introduced in the reaction mixture in the course of the co- condensation with melamine. The obtained resin contains high concentrated dry residue, inconsiderable concentration of free formaldehyde and is stable during storage. It has a short gelatinization time and excellent physical and mechanical properties. It may be used as chemical hardeners e.g. for production of resin bonded and cellulose-fiber chipboards and other composite materials.

IPC Classes  ?

• C08G 12/38 - UreasThioureas and melamines
• C08G 12/12 - UreasThioureas
• C08L 61/30 - Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic and acyclic or carbocyclic compounds
• C09J 161/30 - Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic and acyclic or carbocyclic compounds