Polyester synthetic fiber treatment agent containing (POLY)oxyalkylene derivative and specific inorganic acid and organic phosphoric acid ester compounds, and related compositions and method

Abstract

Disclosed is a polyester synthetic fiber treatment agent containing 5% by mass or more of a (poly)oxyalkylene derivative, 1% by mass or more of an inorganic acid compound, and 5% by mass or more of an organic phosphoric acid ester compound. A 1% by mass waterdiluted liquid of the polyester synthetic fiber treatment agent (containing no solvent) has a pH at 25°C of 5.5 or more and 8.5 or less, the inorganic acid compound (B) is at least one selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, and salts thereof. The organic phosphoric acid ester compound (C) is at least one selected from the group consisting of an organic phosphoric acid ester and a salt thereof having an alkyl group with 16 or more and 20 or less carbon atoms in a molecule.