METHOD OF PRODUCING CARBAMIDE-FORMALDEHYDE RESINS Russian patent published in 2011 - IPC C08G12/12 

FIELD: chemistry.

SUBSTANCE: method involves condensation of formaldehyde to carbamide in molar ratio less than 2.0:1.0 in a medium with variable acidity at temperature not higher than 100°C until achieving viscosity of at least 700 cP. Further, post-condensation at molar ratio of formaldehyde to carbamide 0.95-1.5:1.0 for not less than 30 minutes and final cooling are performed. Not less than 10 minutes after the beginning of the post-condensation step, alkali is added to the reaction mixture at temperature 40-65°C in such an amount that pH lies in the range of 9.0-10.0.

EFFECT: obtaining reactive carbamide-formaldehyde resins with short gel time and stability during storage.

3 cl, 7 ex, 2 tbl