Textiles yarns

Gam, n. yarn thread, twine net. -druck, m. (Textiles) yarn printing. 

In the manufacture of fast cord the first process is to coat paper or textile yarns with a blackpowder/nitrocellulose dope by a dipping process. These yarns are thoroughly dried and a number of them passed through an extruder and given a thick covering of plastic incendiary composition. The cord thus produced is covered with a protective layer of plastic, usually polyethylene. The overall diameter of the cord is about 2-5 mm. 

Spin. In fuse manufacture, to wind on a spiral of textile yarns. 

Fig. 8 Tensile curves of cellulose II fibres measured at an RH of 65% (1) Fibre B, (2) Cor-denka EHM yarn, (3) Cordenka 700 tyre yarn, (4) Cordenka 660 tyre yarn and (5) Enka viscose textile yarn [26]. The solid circles represent the strength corrected for the reduced cross section at fracture. The dotted curve is the hyperbola fitted to the end points of the tensile curves 1,3 and 5. The dashed curve is the fracture envelope calculated with Eqs. 9,23 and 24 using a critical shear stress rb=0.22 GPa... 

Unlike nylon, which is highly crystalline, PET fibers are amorphous after spinning. They are like the molecules shown at the top of Figure 22-6 in Chapter 22. In order to make a usable textile yarn or staple fiber our of PET, it must be drawn under conditions that result in orientation and crystallinity. This is accomplished by drawing at temperatures of about 175°F with stretch 300-400%. As with nylon, the conditions of draw (especially... 

Huizenga, R., Mantingh, J., Pomp-De Wit, F., (1998). Amylopectin potato starch products as sizing agents for textile yarns. World Intellectual Property Organization, International Patent Applieation PCT/NL98/00063. 

During spinning and weaving of textiles (cotton, wool, bast fibres, etc.) breakdown of the textile yarn is frequently observed17. This has an influence not only on the quality of the textile product but also on the production cost, since the machines have to be stopped every time that the yarn is broken. To avoid or reduce the incidence of these harmful consequences, the textile yarn is strengthened with a layer of cellulose. Less than 5% of the breakages that occur with an untreated yarn still occur when the yarn is treated with cellulose. 

The relatively long fiber lengths (about 1 in. (25.4 mm) or longer) on the cottonseed relate to the fiber that is used by the textile industry. This raw cotton fiber, which can be spun into textile yarns, is called lint. However, another type of fiber, linters or fuzz fibers, which are very short, is also produced on the seed along with the lint [44]. The distribution of the lint and fuzz fibers over the seed surface is neither uniform nor random. The base of the seed mostly produces lint fibers, whereas cells near the tip of the seed mostly produce fuzz fibers. 

Buchanan D R and Hardegree G L, Thermal stress analysis of textile yarns . Textile Research Journal, 1977,47, 732-740. 

Relative scales of the spinning processes for staple and filament products are depicted in Table 12.1. The industrial filament process is intermediate to the staple and textile filament processes, in terms of both spinning du oughput and fiber orientation uniformity (here measured by spun birefringence level). Industrial yarns must be uniform enough to be drawn to much higher tenacity levels dian staple yarns, but are not dyed and tlierefore not subject to tire more demanding uniformity requirements of textile yarns. 

ISO 2060, 1994 Textiles—Yarn from packages—Determination of linear densitv (mass per unit length) by the skein method. 

ISO 2062, 199.1 Textiles —Yarn from packages—Determination of single end breaking force and elongation at break. 

The primary fabrication process in the production of synthetic fibers is the spinning—i.e., the formation—of filaments. In every case the polymer is either melted or dissolved in a solvent and is put in filament form by forcing through a die, called spinneret, having a multiplicity of holes. Spinnerets for rayon spinning, for example, have as many as 10,000 holes in a 15-cm-diameter platinum disc, and those for textile yarns may have 10-120 holes industrial yarns such as tire core might be spun from spinnerets with up to 720 holes. 

Another important class of extruded materials consist of filaments and yarns. These are produced by spinning, which is the extrusion of molten material through fine holes in a spinneret. After passing through the spinneret the filaments cool, either in air or in water. If single-filament material is required, as for instance with nylon fishing line, the different filaments are wound up separately. If a textile yarn is required finer filaments produced simultaneously are twisted together before wind-up. 

For linear polyamides, the viscosity of dilute or moderately concentrated solution can be related closely to M . Thus, the molecular weight of polymer can be evaluated from i inh = ln reiA- This is usually measured at a concentration of 0.5 g of polymer in 100 ml of solvent, e.g., m-cresol. A typical value of T i h of nylon-6,6 is one forMn of about 15,000. Another method of characterization commonly used is to measure the relative viscosity (RV) of an 8.4% solution of polymer in 90% formic acid. Typical values of relative viscosity for nylon-6,6 are in the range of 30 to 70. An RV of 41 corresponds toMn of about 15,000, whereas an RV of 60 corresponds to about 19,000. Polymers in the lower range are used for textile yarns, and those in the higher range for industrial yarns. 

Microscopic examination All fibers have distinguishing features that allow either outright identification or classification into a narrower grouping for specialized analysis. Animal hair fibers, for example, have a characteristic scaled surface. In addition, many textile yarns are blends of two or more fiber types. A simple examination with a normal light microscope can establish this and allow the components of the yam to be separated for more detailed evaluation. The major identifying characteristics are ... 

Textile yarn (acetate fibres) is produced in a similar fashion but with much fewer filaments per spinning site (20 to 160) and overall yarn titers between 44 and 670 dtex [43]. Melt spinning is not, to the authors knowledge, found in the literature. 

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