Stabilising polyphenylene oxide against heat - by organic phosphite or thiophosphite and sterically hindered mono-phenol, bis phenol or bis-thiophenol

摘要

A polyphenylene oxide of formula (where R1 and R2 are H, halogen, CN, No2, amino, sulpho, or a (substd.) hydrocarbon, alkoxy, or phenox gp. and n is is not 100), is stabilised by addn. of (1) a phosphite of formula (where R1, R2 and R3 are 6-20C hydrocarbon gps. and X is O or S) and (2) a sterically hindered monophenol of formula (where R1 and R3 are 1-20C hydrocarbon gps. and R2 is H or a 1-20C hydrocarbon gp; R1 and R2 are pref. 1-10C alkyl), or a bisphenol of formula (where 1 A gp. on each ring is OH and the other A gps. are H or 1-20C hydrocarbon, R1, R2 and R5 are 1-20C hydrocarbon, and n = 0-20), or a corresp. thiobisphenol. The polymer does not become discoloured at high temp.