UREA-FORMALDEHYDE RESIN PRODUCTION PROCESS Russian patent published in 1999 - IPC

FIELD: polymer production. SUBSTANCE: resin is prepared by condensation of urea-formaldehyde concentrate with first urea portion and heating in aqueous solution with variable acidity followed by bringing intermediate product into interaction with additional amount of urea, initial and final urea-to-formaldehyde molar ratios being 1:(1.9-2.1) and 1:(1.1-1.4), respectively. Process is distinguished by being conducted in presence of resin viscosity corrector and conducting its finishing phase in presence of buffer additive, while initial concentrate is product containing 65-85% of formaldehyde and its compounds with urea at urea-to-formaldehyde molar ratio 1: (4-6) modified with 1-15% urones and 1-5% triazinones. EFFECT: optimized and intensified synthesis of low-mole urea- formaldehyde resin, and improved working characteristics of product. 1 tbl, 5 ex