METHOD OF PREPARATION OF PHENOLALDEHYDE OLIGOMERS Russian patent published in 1997 - IPC

FIELD: manufacture of plastic foams. SUBSTANCE: phenol- aldehyde oligomers are prepared by polycondensation of phenol and aldehyde in the presence of catalyst. Catalyst components are mixed by spraying at ultrasonic spraying oscillation frequency of 18.100 kHz. The resulting oligomer is then subjected to vacuum drying. Process also involves optionally improving quality of resins and products based thereon. The claimed method makes it possible to obtain phenol aldehyde resins with less molecular weight distribution reduced toxicity due to fuller removal of moisture and unreacted components, and also to improve properties of plastic foams based on said resins. EFFECT: more efficient preparation method. 2 cl, 6 dwg, 1 tbl