The research of reducing the contents of free formaldehyde in foamable phenolic resin

This is research on the influence of the synthesis condition of phenol formaldehyde resin on the contents of free formaldehyde in resin.The results showed that the contents of free formaldehyde in resin is 0.12%～11.57% when the mole ratio of initial formaldehyde to phenol was(1.2～2.4) ∶1;The whole reaction could be divided into two procedures:it could be heated at 65 ℃ and 95 ℃ for 40 min respectively,resulting in lower contents of free formaldehyde;The most suitable dosage of catalyzer was 6%～9% of the amount of phenol;With the increasing use of carbamide,the contents of free formaldehyde would decrease,however,it had the threshold,so optimal dosage of carbamide was 10%～12% of amount of formaldehyde.