The Development Of The Nomex Fiber Blended Fabric And Flame Retardant Heat Resistance

In this paper, two series of flame retardant blended fabrics, namely, Nomex/cotton Nomex 462/Lenzing Viscose FR were developed. The properties of the fibers, the mechanical characteristics of the blended yarns and their fabrics, the flame retardance, heat resistance and mechanical characteristics of the fabrics were studied systematically. The technology on spinning, weaving and finishing were also discussed.It is indicated that the heat resistance of Nomex 450 and Nomex 462 fibers is similar, and the mechanical properties of Nomex 450 fiber are better than those of Nomex 462, its crystallinity and degree of orientation are higher than those of Nomex 462, thus its dyeability is worse than Nomex 462. As to Lenzning Viscose FR fiber, it has a high moisture regain. while its mechanical properties are not as good as those of Nomex fiber.The researches on spinning, weaving and finishing of the series of Nomex/cotton included the followings: a trial spinning of Nomex 450/long-staple cotton, Nomex 450/medium cotton, Nomex 462/long-staple cotton,Nomex 462/medium cotton blended yarns in 5 blending ratios; 21 types of fabrics in 2 sets of weft density using the above yarns being woven; choosing a preferable scheme among the above ones to make bulk production; the desizing method and flame-retardant treatment also being probed. Moreover, 7 types of Nomex 4627 Lenzing Viscose FR blended yarns were spun and their fabrics were woven. And through the experiments, some regular patterns were founded. As to Nomex/cotton series, when the blending ratio of Nomex increases, the breaking tenacity and breaking elongation rate decrease first and then increase, the general mechanical properties of their fabrics become better; the mechanical properties of Nomex 462 blended yarns and their fabrics are a little worse than those of Nomex 450, while their dyeability are very good. With regards to the series of Nomex 4627 Lenzing Viscose FR, the mechanical properties of both yarns and fabrics change following a similar pattern.Results from Vertical Flammability Test and LOI experiments manifest the followings. As the increasing of the blending ratio of Nomex, the LOI of every Nomex/cotton blended fabric increases, while it is smaller than that of 100% Nomex fabric. When in a same blending ratio, fabrics made from both types of Nomex fibers show a similar LOI.The Fabric that after flame-retardant treatment has a higher LOI, and its damaged length, duration of afterglow.duration of afterflame decrease sharply. And to Nomex 462/Lenzing Viscose FR, it is founded for the first time that LOI of both pure raw fabrics are the smallest, the LOI of each of the other 5 blended fabrics increase as the increasing of blending ratio of Nomex 462, and their damaged length, duration of afterglow,duration of afterflame all decrease.Through TG and DSC analysis, some useful results can be given. To both series of Nomex/cotton,Nomex 462/Lenzing Viscose FR blended fabrics, heat resistance becomes better with the increasing of blending ratio of Nomex; and the decomposition temperature of cotton or Lenzing Viscose FR in the fabric increase; each changing stage of these fabrics shows an absorption of heat, and it needs a large quantity of heat, thus in order to support the combustion or decomposition of these fabrics, much heat will be needed and it should be provided continuously.