UREA-FORMALDEHYDE RESIN PRODUCTION PROCESS Russian patent published in 2007 - IPC C08G12/12 C08G12/40 

FIELD: polymer production.

SUBSTANCE: invention, in particular, relates to production of urea-formaldehyde resins widely used in wood-working industry. Process according to invention is implemented via condensation of urea-formaldehyde concentrate with urea on heating first in neutral or low-alkaline medium and then in acidic medium in presence of catalytic additive composed of formaldehyde, sodium hydroxide, and sulfuric acid at molar ratio 1.0:(0.4-0.5):(0.1-0.3), respectively, followed by co-condensation of formed product with additional amount of urea in neutral or low-alkaline medium at initial and final urea-to-formaldehyde molar ratios 1.0:(1.9-2.1) and 1.0:(1.1-1.6), respectively. Action of impurities in urea-formaldehyde concentrate and urea is neutralized with sodium hydroxide solution until pH of mixture 6.0-8.0 is attained. Stabilization of pH of reaction mixture is achieved by using catalytic additive in amount 0.1-0.3% of the weight of initial formaldehyde in urea-formaldehyde concentrate.

EFFECT: simplified technology with high principal characteristics of resins preserved.

3 cl, 1 tbl, 4 ex