Effect of Processing Factors and Fiber Properties on the Arrangement of Fibers in Blended Yarns

Abstract

A study was made of the influence of processing factors on the average disposition of fibers within a section and on the intimacy of mixing, when the blending constituents differ widely with respect of fiber dimensions. A simplified measure was developed to characterize the preferential arrangement of fibers within a cross section, and the effects of spinning factors were evaluated. It was found that long and fine fibers have a definite tendency to occupy the core, while short and coarse fibers concentrate at the surface, and of the spinning factors, only strand width at the delivery nip has a significant effect on the arrangement. Further, no significant preferential segregation of the constituents was noticed across the width of the drafted strand, indicating that the biased arrangement develops during spinning. Spinning from multiple rovings showed promise of improving the preferential arrange ment, but the average position of the constituent in the yarn section does not have any large effects on the strength or the extension of the yarn. When blending is done prior to the card, intimate mixing of the components, close to ideal, is realized in the yarn even in blends composed of fibers that differ considerably in length and fineness. But with blending at the ring frame, the components are distributed almost independently of each other and, in such yarns, the variability in the blend proportion is of the same order as the variability in the total number of fibers. Evidence is presented to show that adjoining fibers tend to move together during drafting, and in order to minimize variation in the blend proportion longitudinally, adequate lateral intermingling of the components must be obtained.