METHOD PREPARING CARBAMIDE-FORMALDEHYDE RESIN Russian patent published in 2001 - IPC

FIELD: chemical industry. SUBSTANCE: described is method of preparing carbamide-formaldehyde resin by condensation of carbamide-formaldehyde concentrate with first portion of carbamide in the presence of viscosity and heating regulator in aqueous solution having variable acidity followed by aftercondensation of the resulting product with additional amount of carbamide in the presence of buffer additive at initial and final carbamide to formaldehyde molar ratio of 1:(1.9-2.1) and 1:(1.02-1.7) respectively and cooling of final resin. Condensation of carbamide-formaldehyde concentrate and carbamide is carried out throughout entire process in the presence of buffer additive introduced in two steps: prior to introducing first carbamide portion and in after condensation stage, respectively. EFFECT: simplified process and improved quality of the desired product. 4 ex, 1 tbl