Study on Manufacturing PCT/PPS Flame Retardant Fiber by Sheath/Core Conjugate Spinning

In this study, fiber for wigs was produced by a sheath/core conjugate spinning machine using poly PCT (cyclohexanedimethanol terephthalate) as a sheath polymer and PPS (polyphenylene sulfide) as a core polymer. In order to withstand the high temperature of hot irons used in hair salons, the fiber was made of high heat resistant polymers. Also, an epoxy-type chain extender was added so that the MFI (melt flow index) of PCT, which had a lower melt velocity than PPS, could become similar to that of PPS. In addition, a phosphorus flame retardant was added to PCT, which has no flame retardancy, so that the limiting oxygen index (LOI) was raised to over 29. The strength and elongation of the manufactured yarn varied depending on the drawing method, draw ratio, and heat set temperature. The strength increased as the un-drawn yarn passed faster through the draw roller, and it also increased as the draw ratio increased. As the heat set temperature increased, the strength increased and the elongation decreased. The strength and the elongation of the PCT/PPS conjugate fiber were in the middle of the ranges of those of the single spun PCT and PPS fibers.