Spinning of yams

Fabrics are two-dimensional materials made from fibers. Their primary purpose is to cover things and they are commonly used in clothes, carpets, curtains, and upholstery. The motive for covering may be aesthetic, thermal, or acoustic. Fabrics are made out of or twisted bundles of fibers. The spinning of yams can occur in two ways staple fibers can be twisted into a thread ( spun yam ) or monofilaments can be twisted into a similar usable thread ( filament yam or continuous filament yam ). All these definitions are important in order to understand the conversation of the fiber industry. 

Spinning of yams (from godown to post-spinning operations)... 

The viscose obtained from Cross and Bevan was so successful for production of lamp filaments that Steam asked Topham to try to spin it for use in textiles. The first experiments failed dismally. After several years of painstaking work, Topham made several discoveries essential to the spinning of yam from viscose aging (ripening) of the solution, filtration to remove particles, multiple-hole platinum spinnerettes, and a circular, centrifugally operated yarn collecting device that twisted the yam and packaged it in convenient cake form [117]. The Topham box, as it is still called, or variations of it are still on many of the continuous-filament rayon machines today. 

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. 

The economics of recovery are a very strong function of the amount of zinc used in the preparation of the yarn and the ratio of acid to zinc in the spinning bath. In manufacturing industrial yarns and tire cords, it is common to use 4.5 to 7.5 kg of zinc per 100 kg of yam. This high concentration of zinc makes recovery extremely attractive. Textile yams use less zinc, and although recovery is still the most economic solution, it offers less of a return. These two cases are presented as extremes, with many plants falling between the two values. 

PTT polymer pellets must be dried to a moisture level of <30 ppm, preferably in a close-loop hot air dryer, to avoid hydrolytic degradation during melt processing. Drying is carried out with 130 °C hot air with a dew point of < -40 °C for at least 4 h. Because of the faster crystallization rate, PTT pellets are already semicrystalline after pelletizing, and do not require pre-crystallization prior to drying as with PET. The dried polymer is extruded at 250-270 °C into bulk continuous filaments (BCFs), partially oriented yam (POY), spin-draw yam (SDY) and staple fiber. 

Brown and Chuah [84] and Oppermann el ol. [36] studied the spinning of partially oriented yam (POY) as a function of take-up speed from 500 to 5000m/min. Figures 11.18 and 11.19 show, respectively, development of the tenacity and elongation as a function of spinning speed. Tenacity increases with increasing... 

Polejes, J. D Nylon and polyester production - in practice, Presentation given at the Fundamentals of Melt Spinning and Yam Production Conference, Clemson University, Clemson, SC, February 26-27, 1992. 

The stress-induced crystallization influences the ability to sustain the stress of deformation occurring in the spin line. Optical micrographs of fluffs allow the assumption of different deformation or stress behavior of core and skin layers of spun fibers, as shown in Figure 13.1. The reason for this kind of yam break can... 

The simplest procedure for grafting copolymerization, in terms of number of components in the reaction medium, is a bulk polymerization of the monomer in mixture with the molten polyamide. This has been claimed in an earlier patent (2), related to improvements in dyeability and hydrophylic properties of the resulting yam, obtained by melt spinning of the product of reaction with monomers such as 2,5-dichloro styrene, lauryl methacrylate, N-vinyl pyrrolidone, and N-vinyl carbazole. 

Furthermore, the types of yam structures that Willoughby (5) described in the Seip textiles as vegetal core with red-stained rabbit hair wrapped around if can only be achieved in coloring the fibers before spinning. Therefore, the prehistoric artisans had to have specific knowledge about dyes and how to apply them. 

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