METHOD OF PRODUCING UREA FORMALDEHYDE RESIN Russian patent published in 2012 - IPC C08G12/12 C08G12/40 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing urea formaldehyde resin. The method involves condensation of carbamide and formaldehyde in initial and final molar ratio of 1:1.95-2.0 and 1:1.05-1.15, respectively, in a medium with variable acidity while heating, adding a polybacid alcohol as a modifying additive and post-condensation with an additional amount of carbamide. Formaldehyde is added as part of a low-methanol carbamide-formaldehyde concentrate with 60±0.5 wt% formaldehyde, 25±0.5 wt % carbamide, and water. Condensation is carried out at temperature 90-100°C for 30-60 minutes while changing pH from 9.0-7.0 to 5.8-5.0, in the presence of an acid catalyst and pentaerythritol, which is taken as a modifying additive in amount of 0.35-2.0% of the total weight of the obtained urea formaldehyde resin. Further, carbamide is added at temperature 65-90°C and post-condensation is carried out for 30-60 minutes, while changing pH to 7.5-8.5 and then cooling to 20-30°C.

EFFECT: high technological effectiveness of the process of producing resin while simultaneously improving physical and mechanical properties of articles made from said resin.

1 cl, 1 ex, 1 tbl