PURPOSE: To provide the title economically producible fiber excellent in flame resistance and mechanical strength, made up of polyethylene terephthalate and a phosphorus-contg. polyester prepared by copolymerization of a specific organophosphorus compound, exposing the former component on the surface.
CONSTITUTION: The objective fiber made up of (A) polyethylene terephthalate or a phosphorus-free polyester predominant in polyethylene terephthalate and (B) a second polyester containing ≥500ppm of P atom, prepared by copolymerization of an organophosphorus compound of the formula (E is CH2CH2; Ar is aromatic group; (m) and (n) are each such integer as to total 1-20), with at least part of the component A exposed on the fiber surface. It is suggested that the organophosphorus compound be prepared by reaction under heating in a solvent between diphenylphosphine oxide and an aromatic dihydroxyl compound such as hydroquinone followed by reaction of the resulting product with ethylene carbonate in a solvent.
ABE TOSHIKAZU
MATSUMOTO TETSUO
