METHOD FOR PREPARING CARBAMIDE-FORMALDEHYDE RESIN Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to preparing carbamide-formaldehyde gluing resins. Resin is prepared by condensation of carbamide with formaldehyde in medium with variable acidity followed by concentrating and additional condensation with additional amount of carbamide in alkaline medium firstly and then in acid medium at pH = 4.5-5.8 in the presence of strong acid ammonium salt that is a modifying addition simultaneously. If necessary, stabilization with diphenylolpropane is carried out. Process is carried out up to preparing water-proof resin with final mass ratio carbamide, formaldehyde, diphenylolpropane and strong acid ammonium salt = 100 : (50-75) : (0.0-3.0) : (0.05-1.0), respectively. Invention provides preparing resins with high gluing properties and reduced content of highly volatile compounds. EFFECT: improved preparing method. 2 tbl, 3 ex