Treatment agent for a polyester synthetic fiber, first treatment agent for a polyester synthetic fiber, second treatment agent for a polyester synthetic fiber and polyester synthetic fiber

Abstract

The present invention addresses the problem of providing: a treatment agent for a polyester synthetic fiber, by means of which the quality of fibers to which the treatment agent adheres is improved; and a polyester synthetic fiber obtained using the treatment agent. This treatment agent for a polyester synthetic fiber is characterized in that it comprises a smoothing agent (A), an antistatic agent (B), and a non-ionic surfactant (C), wherein the non-ionic surfactant (C) contains a (poly)oxyalkylene derivative (C1) of an aromatic alcohol. The (poly)oxyalkylene derivative (C1) of the aromatic alcohol is a compound with a structure such that at least one alkylene oxide, selected from ethylene oxide and propylene oxide, is added in a total amount of at least 1 mol and at most 100 mol per 1 mol of an alcohol represented by the following general formula (1).In the general formula (1), R1 represents a hydrocarbon group with 10 to 20 carbon atoms.