Patent ID: 6864343

Claim:
A purified brominated polyphenylene oxide having a molecular skeleton obtained by condensing tribromophenols, which satisfies the following requirements: (A) Its 20 wt. % solution in chloroform has an absorbance at 600 nm of not larger than 0.6; (B) When 50 ml of ion-exchanged water is added to its 1.00 g/30 ml solution in dioxane, the resulting solution has an electroconductivity of not larger than 10 μ/cm measured at 25° C.; and (C) When a mixture comprised of 20% by weight of the brominated polyphenylene oxide and 80% by weight of triphenyl phosphate is heated at 280° C. for 20 minutes, the halide ion increase therein is not larger than 10 μmols per gram of the brominated polyphenylene oxide; wherein said purified brominated polyphenylene oxide satisfying said requirements is prepared by subjecting a solution of a crude brominated phenylene oxide obtained by condensing tribromophenols, to a decolorization treatment, subjecting the decolorized solution to a first liquid-liquid extraction with water, substantially completely separating the brominated polyphenylene oxide solution from the aqueous phase resulting from the extraction, subjecting the separated brominated polyphenyleneoxide solution to at least one additional liquid-liquid extraction with water, substantially completely separating the brominated phenylene oxide solution from the aqueous phase, and precipitating, filtering and drying a solid purified brominated polyphenylene oxide.