METHOD OF UREA-FORMALDEHYDE RESINS PRODUCTION Russian patent published in 2009 - IPC C08G12/12 C08G12/40 

FIELD: chemistry.

SUBSTANCE: method of producing urea-formaldehyde resins is ensured by condensation of carbamide and formaldehyde with ammonia and modifier added being mixed solution of nitroxyl radical 4-oxo-5-methylene-3-(N-piperidinomethyl)-2,2,6,6-tetramethylpiperidine-1-oxyl and ionol (2,6-di-tert-butyl-n-cresol) in butyl alcohol. Originally formaldehyde and ammonia are mixed to pH - 8. The prepared mixture is heated up to 50°C, mixed with carbamide, and 5 minutes later a modifier is added and heated up to 85°C, maintained for 5 min to pH - 5. Further the prepared resin is cooled to 50°C and stabilised with aqueous ammonia solution to pH - 7-7.5.

EFFECT: lower resin and air concentration of free formaldehyde in workrooms in manufacturing insulating boards with improved physicomechanical characteristics.

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