Method of treating fiber

摘要

A polyester fiber suitable for reinforcing resin can be obtained by subjecting a fiber obtained by melt-spinning a polyester which exhibits anisotropy in its molten state to (a) a treatment comprising adhering to the fiber a solution of an epoxy group-containing compound dissolved in an organic solvent which is inert to the said compound, and then drying the resulting fiber; or (b) a treatment comprising making the fiber contact with at least one member selected from the group consisting of sulfur trioxide, chlorosulfonic acid, fluorosulfonic acid, and an aqueous sulfuric acid solution having a concentration of 30 to 95% by weight.