Spinning Woolen

In woolen spinning there are no highly efficient mechanical methods to remove VM. Generally, very clean scoured wool, combed wools, or carbonized wool must be used as inputs, or fabrics must be carbonized. 

Woolen spinning is thus a very short sequence compared to worsted processing. Woolen yams are economically uncompetitive with worsted yams even at relatively coarse yam counts, a result of the yams being virtually made on the carding machine, the expense of the much larger card used, the low dehvery speed, and the very low card production in spinning fine yams, resulting from the low deUvery speed. 

Staple sta-p9l [ME, fr. ME estaple, fr. MD stapel emporium] (14c) n. Natural fibers or cut lengths from filaments. The staple length of natural fibers varies from less than 1 in. as with some cotton fibers to several feet for some hard fibers. Manufactured staple fibers are cut to a definite length, from 8 in. down to about 1-0.5 in. (occasionally down to 1 in.), so that they can be processed on cotton, woolen, or worsted yarn spinning systems. The term staple (fiber) is used in the textile industry to distinguish natural or cut length manufactured fibers from filament. 

Friction spurning is a variation of the open-end spinning system and often referred to as the DREF system. In this system, one or more slivers are fed onto a rapidly rotating card drum which opens the si iver to form single fibers. The separated single fibers are blown from the card dram by a stream of air onto the junction of two parallel perforated drams turning in the same direction. The rotating perforated drams under suction cause the fibers to be compressed and twist around aie another to form a uniform yam which is continuously removed onto a spool. The resultant yarns are bulky and have properties similar to woolen yarns. 

After scouring, the wet wool is carbonized with diluted sulfuric acid to remove plant-derived components. The wool is then dried, pressed, and made into yarns with woolen spinning machines (Section 3.2.1). 

Waste silk and parts of the cocoon not suitable for reeling may be processed into staple fiber yarns according to the schappe or bourette spinning method, depending on their staple length. These procedures are similar to the worsted yarn process or the woolen spinning process (Chapter 3). 

For the production of woolen yarns, ring spinning can also be economical owing to their relatively low twist, which reduces the economic advantage of nonconven-tional spinning machines. 

Carded woolen spinning is a very flexible spinning method, with which several very different fiber types can be processed. Wool and fine animal hair as well as pure or blended synthetic fibers can be spun. Furthermore, waste from other spinning processes as well as regenerated wool from textile waste can be used, see Fig. 3.27. 

Figure 3.27 Flow chart for carded woolen spinning method...

Figure 3.30 Carded woolen spinning frame (Kirchenberger, 1986) (1) roving bobbin,...

The conventional woolen card incorporates a web sheer at the end that divides the fiber mat into multiple parallel strips depending on the required fineness. These strips are directly fed to a rubber spinning frame that compacts them into rovings and winds them onto bobbins. As with the rubber draw frame used in worsted yarn spinning, the sliver cohesion is caused by false-twisting the fiber strips. 

For very fine woolen yarns (30-40 tex), the selfactor spinning frame can still be used economically today. 

With the nonconventional woolen spinning method, which was developed at the Institut fiir Textiltechnik at the RWTH Aachen, Germany, within a research project of the European Union, the slivers are produced on a novel compact card with only one tambour. They have a titer of about 4 ktex. Without additional roving formation, they can be spun directly into a yarn on a nonconventional woolen ring spinning frame or a modified OE-rotor spinning machine. 

Figure 3.31 Flow chart for nonconventional woolen spinning (Hormes, 1991)...

Recycled libers can be processed very well with the woolen spinning method. Therefore, research work in woolen spinning is of particular importance. 

The woolen staple fiber yarns for carpets are usually manufactured according to the woolen spinning principle. 

The tearing fibers produced according to the processes described can again reach the textile production process as raw materials. This happens, for example, in the field of woolen spinning (outerwear fabrics, carpet yarns), nonwoven production (sound and heat damping materials), and for the production of composites for the automobile industry (hat racks, inside covers). Additional applications are cleaning and wiping cloths made from woven friction yarns or from stitch-bonded nonwovens. 

The woolen spinning process is one of the oldest textile recycling processes. It was introduced more than 100 years ago and is well established today. In some regions of Europe, for example, in the area of Prato in Italy, woolen spinning is the dominant industrial branch. 

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