PURPOSE: To obtain a high-quality phenolic resin outstanding in processability and heat resistance without impairing the other physical properties, by incorporating, as the flame-retardant, a polythiol phosphorus-contg. compound as a phosphine oxide derivative during the phenolic resin production.
CONSTITUTION: During the phenolic resin production process, that is, in the reaction between a phenol and aldehyde or in the curing of the precondensate from the phenol and aldehyde, pref. 5W40wt%, based on the phenolic resin, of a phosphine oxide derivative of formula I (X is 0W2, Y is 1W3 and X+Y=3; R is of formula II or III) prepared by reaction, at 90W150°C (pref. 90W140°C) using a catalyst such as p-toluenesulfonic acid, of tris(hydroxypropyl)phosphine oxide and thioglycolic acid and/or mercaptopropionic acid is incorporated in the system, thus obtaining the objective phenolic resin.
ISHIZUKA YOSHITSUGU
BABA YUJI
SASAGAWA NORIMOCHI
Next Patent: FLAME-RETARDANT POLYESTER COMPOSITION