Abstract:

In order to improve the flame retardance and spinnability of polyamide 6 (PA6) fibers, a synergetic flame-retardant system of pentaerythritol phosphate (PEPA) / zinc diethyl phosphate (ZDP) was designed. Flame retardant polyamide 6 (PA6) / PEPA / ZDP composites were prepared by a melt blending method in a twin-screw extruder. The influence of different flame retardant components on the flame retardancy and the spinning process and properties of the optimal flame retardant ratio were studied by scanning electron microscopy, differential scanning calorimetry, thermo gravimetry, cone calorimetry, limit oxygen index (LOI) and UL-94 rating. The results indicate that PEPA can decrease the thermal stability of  PA6, but ZDP can improve the thermal stability of the composites, which can be complementary with each other. When the mass ratio of PEPA and ZDP is  10 : 5 in PA6, the value of LOI reaches 28%, and the flame burning time of the UL-94 is reduced obviously. The residual carbon amount of cone calorimetry increases by 6.56%, and the value of total heat release decreases by 34.5%. It is found that the composites have excellent spinnability. The breaking strength is 1.34 cN/dtex and The as-spun fibers elongation at break is 33.99% after as-spun fibers are subjected to hot stretching by  three times.

Key words: polyamide 6, pentaerythritol phosphate, zinc diethyl phosphate, spinnability, flame retardancy