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

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing urea formaldehyde resin, which can be used in wood processing industry when producing wood chipboards and fibreboards, plywood and laminated wood structures. The method involves condensation of carbamide and formaldehyde with initial and final molar ratio of 1:1.95-2.1 and 1:1.01-1.6, respectively, in a variable pH medium while heating, and post-condensation with an additional amount of carbamide. Formaldehyde is added in form of paraform and 37% formaldehyde solution. Condensation is carried out at temperature 90-100°C for 30-60 minutes while varying pH from 9.0-8.0 to 5.8-5.0. Further, carbamide is added and post-condensation is carried out at temperature 65-90°C for 30-90 minutes, while changing pH to 7.5-8.5. The mixture is cooled to temperature 20-30°C.

EFFECT: low toxicity of the obtained urea formaldehyde resin.

2 cl, 1 ex