METHOD OF PREPARING PLASTICIZED NOVOLAC- PHENOLFORMALDEHYDE RESIN Russian patent published in 1997 - IPC

FIELD: manufacture of friction components and foundry industry. SUBSTANCE: plasticized phenol-formaldehyde resin is synthesized by alkylation of phenol with plasticizing agent that (tall oil and/or aromatic compound with end olefin groups) in the presence of strong acid at phenol to plasticizing agent to acid weight ratio of 100:(1-25):(0.2-0.56), respectively at 80-125 C. Sodium hydroxide is added in amount of 0.25- 0.6 part per 1 kg of strong acid till it is fully neutralized. Formaldehyde and oxalic acid are then added and condensation is carried out at boiling temperature followed by drying of resin under vacuum to obtain resin containing 0.05-0.33 % free phenol and having viscosity of 54-119 MPa*s. EFFECT: more efficient preparation method. 1 tbl