| The fire hazards caused by the textile products are over one half of the fire hazards every year. Therefore, it is of necessity to develop the flame-retardant (FR) clothing with excellent thermal resistance and fire retardancy. Nomex is a popular fiber used for the FR clothing. However, due to its high price, Nomex blended yarn has been being developed to reduce the cost of yarn manufacturing. At present most of FR yarns are spun using the traditional ring spinning technology in China. The research on the rotor spinning of the Nomex fiber is seldom, although the rotor spinning has many merits compared to the ring spinning. This thesis aims to find the optimum processing parameters for the rotor spinning of the Nomex/Flame-retardant Acrylic blended yarn with good mechanical and physical properties and flame retardancy conforming to the standard.First, the effects of the combination of the navel and opening roller on the yarn properties are investigated experimentally. In the experiment, we chose three kinds of navels, i.e., the ceramic navel, the chamfer navel and the antistatic navel, and three types of opening rollers, i.e., needle roll, OK37 and OK40 according to the fibers' properties. The spinning process was smooth and there were almost no end-breaks when the OK37 opening roller was combined with the three navels, while end breaks often occurred when OK40 opening roller was used. The fuzzy decision method and clustering analysis were adopted to analyze the experiment data and an optimum combination of the antistatic navel with the OK37 opening roller was determined.Secondly, the effects of the rotor speed, opening roller speed and twist multiplier on the yarn properties were investigated based on the uniform experiment design. The regression analysis show' that such properties of the Nomex/FR Acrylic blended yarn as the tenacity, breaking elongation, CV value and hairiness index are affected to different extents by the rotor speed, opening roller speed and twist multiplier. The twist multiplier is the most significant factor that affects the yarn properties. The CV value has a quadratic relationship with the twist multiplier, while the rotor speed and the opening roller speed have insignificant effects on the CV value. The yarn tenacity was influenced linearly by the product of the rotor speed and the twist multiplier and was influenced insignificantly by the opening roller speed. The hairiness was mainly affected by the twist multiplier. Based on the regression analysis, the optimal model was established and solved so that the optimum spinning parameters for rotor spun Nomex/FR Acrylic yarn were obtained, i.e., the rotor speed is 30,000 r/min, the opening roller speed is 6,000r/min and the twist multiplier is 500. The optimum parameters were verified experimentally.Finally, the flame-retardant fabric samples were woven from the Nomex/FR Acrylic yarn rotor-spun by using the optimum spinning parameters. The tests show that the indexes regarding the flame-retardancy, the mechanical properties and the comfort of the fabric conform to GB8965-1998, the Chinese standard of flame-retardant protective clothing. |
