Production of Filaments and Fibers

From 1910 onward waste filament yam had been chopped into short lengths suitable for use on the machinery designed to process cotton and wool staples into spun yams. In the 1930s new plants were built specifically to supply the staple fiber markets. During World War II the production of staple matched that of filament, and by 1950, staple viscose was the most important product. The new spun-yam oudets spawned a series of viscose developments aimed at matching the characteristics of wool and cotton more closely. Viscose rayon was, after all, silk-like. Compared with wool it lacked bulk, residence, and abrasion resistance. Compared to cotton, it was weaker, tended to shrink and crease more easily, and had a rather lean, limp hand. 

Jets for continuous filament textile yam are typically 1 cm diameter gold—platinum ahoy stmctures with 20—500 holes of 50—200 p.m diameter. Tire yam jets are also 1 cm in diameter but typicahy use 1000—2000 holes to give the required balance of filament and yam denier. Staple fiber jets can have as many as 70,000 holes and can be made from a single dome of ahoy or from clusters of the smaller textile or tire yam jets. The precious metal ahoy is one of the few materials that can resist the harsh chemical environment of a rayon machine and yet be ductile enough to be perforated with precision. Glass jets have been used for filament production, and tantalum metal is a low cost but less durable alternative to gold—platinum. 

Monofilament yarns consist of a single filament. The filament size is much larger than those found in multifilament yarn. Consequently, monofilament is relatively stiff and is used mainly for the production of rope and twine. Fiber size range is typically 75 to 5000 denier. Monofilament fiber is usually produced from polypropylene homopolymer with a relatively low melt flow index in the range 3.5 to 5.0 grams/10 min. 

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,... 

In Table II the U.S. production of man-made fiber is further divided into filament and staple fiber, and the U.S. consumption of cotton and wool is included. On the basis of these data domestic man-made fibers accounted for over 70% of all of the fiber consumed in the U.S. in 1982. These numbers, as well as those in Table I, clearly indicate the importance of the man-made fiber production industry with respect to the U.S. and the world s textile industry. 

The range of products that can be made by extrusion is very large rods, pipes, hoses, sheets, films, profiles, filaments and fibers, wire coatings, etc. 

Boron/tungsten fiber applications include the use of filaments and of boron/tungsten fiber reinforced prepreg tape, aluminum matrix composites, and boron/graphite structures. The major applications for these structures are found in the aerospace market and about 25% in sporting goods markets [36]. SiC/carbon fiber reinforced products include aluminum, titanium, and ceramic matrix composites. Major applications for these structures are also found in the aerospace market, minor uses in the industrial market [37]. 

It can be concluded that PBT is polymer used in both injection molding and extrusion processes today. The easy processability of PBT in extrusion processes such as meltblowing, spunbonding, nettings, monofilaments, multifilaments (staple fibers and filament yarns) and films are resulting in the production of new and innovative materials for extrusion. 

Fibers are the basic element of nonwovens world consumption of fibers in nonwoven production is 63% polypropylene, 23% polyester, 8% viscose rayon, 2% acrylic, 1.5% polyamide and 3% other high performance fibers [8]. The data in Fig. 10.4 shows the market share of important polymers and fibers in the nonwovens market. Manufacturers of nonwoven products can make use of almost any kind of fibers. These include traditional textile fibers, as well as recently developed hi-tech fibers. Future advancements will be in bicomponent fibers, micro-fibers (split bicomponent fibers or meltblown nonwovens), nano-fibers, biodegradable fibers, super-absorbent fibers and high performance fibers. The selection of raw fibers, to a considerable degree, determines the properties of the final nonwoven products. The selection of fibers also depends on customer requirement, cost, processability, changes of properties because of web formation and consolidation. The fibers can be in the form of filament, staple fiber or even yam. 

The word "textile" was originally used to define a woven fabric and the processes involved in weaving. Over the years the term has taken on broad connotations, including the following (1) staple filaments and fibers for use in yarns or preparation of woven, knitted, tufted or non-woven fabrics, (2) yarns made from natural or man-made fibers, (3) fabrics and other products made from fibers or from yarns, and (4) apparel or other articles fabricated from the above which retain the flexibility and drape of the original fabrics. This broad definition will generally cover all of the products produced by the textile industry intended for intermediate structures or final products. 

For melt spinning, spinnerets made of steel are used. For the production of filament yarns, these plates have up to several hundred boreholes. Spinnerets for staple fiber production using conventional spinning methods have up to 10,000, and for compact spinning methods even up to several 100,000 capillaries. 

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