METHOD OF SYNTHESIS OF ESTERIFIED PHENOLFORMALDEHYDE OLIGOMERS Russian patent published in 1997 - IPC

FIELD: chemical technology. SUBSTANCE: resol phenolformaldehyde resins esterified with alcohols were synthesized by stages. Firstly, diphenylolpropane is condensed with paraform solution in an organic solvent taken from the following group: methyl, ethyl, propyl, isopropyl, butyl, isobutyl alcohol, ethylcellosolve, butylcellosolve. Mole ratio of diphenylolpropane and paraform = 1:(5-6) and condensation is carried out up to content of formaldehyde in reaction mixture 7-9 wt.-%. Then an additional amount of diphenylolpropane is added up to its mole ratio with paraform = 1:(2-4) and condensation is continued up to formaldehyde content ≅ 1 wt.-%. The obtained product of condensation is esterified at 50-70 C, at medium pH = 2-3 and mole ratio organic solvent : diphenylolpropane = (3-15):1. EFFECT: decreased time of process, increased esterification degree, decreased content of unreacted monomers in the end product. 2 tbl