Fiber processing solution-spinning

Spectra AUied Signal s trade name for its ultrathin polyethylene fibers that are about 10 times stronger than steel. See fiber processing, gel-spinning fiber processing, solution-spinning. 

In solution spinning process, the polymer is used as a solution by dissolving polymer in an appropriate solvent, whereas in the melt spinning process, the polymer is in the molten state. However, in both the cases, the polymer (either in the molten or in the solution form) is streamed through a spinneret, which is a special kind of plate with extremely fine holes for the fibers. The solution spinning may be of three types. 

By far the greatest use of secondary cellulose acetate is as cigarette filter tow. At a D.S. of ca. 2.4 the cellulose acetate is soluble in acetone and the resulting solution in spun into fibers using solution spinning. The removal and recovery of the acetone is the most expensive aspect of the spin process. An aligned tube of these fibers is the actual "filter" on a cigarette. 

The second ceUulosic fiber process to be commercialized was invented by L. H. Despeissis (4) in 1890 and involved the direct dissolution of cotton fiber in ammoniacal copper oxide Uquor. This solvent had been developed by M. E. Schweizer in 1857 (5). The cuprammonium solution of ceUulose was spun into water, with dilute sulfuric acid being used to neutralize the ammonia and precipitate the ceUulose fibers. H. Pauly and co-workers (6) improved on the Despeissis patent, and a German company, Vereinigte Glanstoff Eabriken, was formed to exploit the technology. In 1901, Dr. Thiele at J. P. Bemberg developed an improved stretch-spinning system, the descendants of which survive today. 

Doped silicon, conductivity in, 23 35 Doped/undoped electrochromic organic films, 6 580-582 Dope-dyeing, 9 197 Dope-making process, in acrylic fiber solution spinning, 11 204 Dope solids, in air gap spinning, 11 209 Doping, 23 838—839 calcium, 23 842-844 conducting polymers, 7 528-529... 

Cellulose Acetate and Triacetate Fibers. Polymer solutions arc convened into fibers by extrusion. The dry-extrusion process, also called dry spinning, is primarily used lor acelate and triacetate. 

Two methods are used to prepare hollow fibers solution spinning and melt spinning [98,99], The most common process is solution spinning or wet spinning, in which a 20-30 wt% polymer solution is extruded and precipitated... 

Cationic dyes are also used to dye polyacrylonitrile fibers during the spinning process either from dimethylformamide solution or in the gel stage subsequent to aqueous spinning processes. 

PAN homopolymer is not a true TP. It is a polar crystallizing polymer that undergoes chemical decomposition before crystalline melting at temperatures above 300C (572F). The almost pure homopolymer, however, can be processed into fiber (acrylic fibers) through its spinning from solutions (Chapter 6). PAN is also used as a base material... 

Melt or solution spinning of synthetic fibers is a marvel of modern technology. Fiber lubrication, which is of the utmost importance in this high-speed process, is achieved by the application of spin finish—a combination of oils and surfactants. A typical spin line for the production of polyester staple fiber is shown schematically in Figure 2. The number of filaments, which can vary from tens to thousands, come into contact with various parts of the machinery, some of which are heated for proper fiber modification. To replenish the lost finish and to ensure adequate lubrication,... 

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