Rieter

General

Index

Since the introduction of this spinning system, rotor spun yarns have become firmly established in certain ranges of application, for both woven and knitted fabrics. In many cases processing rotor-spun yarns into end products has even offered advantages over ring-spun yarns, resulting in higher-quality end products. For example, ring-spun ply yarns have been successfully replaced by single rotor-spun yarns. Early reservations regarding the use of rotor-spun yarns due to their yarn structure and the fact that the hand of the finished article was initially considered too stiff and harsh for knitted fabrics have been dispelled. However, it became apparent in mill operations that ring-spun yarns could not simply be replaced by rotor-spun yarns on weaving or knitting machines. It was very soon discovered that machine settings, such as air injection on the air-jet weaving machine or sinking depth on the circular knitting machine, had to be adjusted to the properties specific to rotor- spun yarns (hairiness, yarn structure, tendency to snarl, etc.). Some of the prejudices against the processability and suitability of rotor-spun yarns in end products date back to the time before all yarn processors had adjusted their machine settings to the new type of yarn.

However, rotor-spun yarns were, of course, used successfully first of all where the specific properties of rotor-spun yarns corresponded particularly well to the requirements of the end products. This was the case in a surprisingly wide range of end products:

  • workwear, such as smocks, overalls and hospital attire;
  • denim fabrics in both light (shirts, blouses) and heavy weights (jeans, coats);
  • rough-surface fabrics for outerwear (flannels) and sheets (so-called beaver sheets);
  • in the coarse count yarn sector (blankets, curtains, textile wall coverings, home textiles);
  • in the fine count yarn sector (sheets made from blended yarns);
  • technical fabrics, e.g. coating substrates, laminates for facial protection;
  • hand towels. bath towels, etc, rotor-spun yarns in both warp and weft, as well as pile, preferably loop fabric;
  • T-shirts made from single jersey (dominated by rotorspun yarns).

Despite the approx. 15 - 20% lower yarn tenacity of rotorspun yarns, the difference is reduced in fabric strength. The strip tensile strength and tear propagation strength of fabrics made from rotor-spun yarn is only 10 - 15% less than that of comparable ring-spun yarns. This is attributable to rotor-spun yarns‘ gain in work capacity due to their better elongation at break and smaller variations in breaking strength (CV% cN/tex). The air permeability of comparable fabrics is some 20% greater with rotor-spun yarns, bursting pressure about the same as for fabrics made from ring-spun yarn. All these statements refer to the yarn count range covered by the rotor spinning system of tex 200 - 10 / Ne 3 - 60 / Nm 5 - 100 and a minimum number of 90 - 100 fibers in the case of man-made fibers and 100 - 120 for cotton. The use of rotor-spun yarns is still limited where especially high fabric strength is required, for example for men‘s shirting fabrics.