Page 614 - Carrahers_Polymer_Chemistry,_Eighth_Edition

Polymer Technology 577

in the United States, the international standards are generally determined by the International
Organization for Standardization (ISO). Table 18.2 contains a brief listing of some of the ISO and
FTC names for some of the most utilized fi bers.
Fiber production continues to increase for most general groupings. Table 18.3 contains approxi-

mate fiber production by fi ber type.
The dimensions of a filament or yarn are expressed in terms of a unit called the “tex,” which is a

−6

measure of the fineness or linear density. One tex is 1 g/1,000 m or 10 kg/m. The tex has replaced
denier as a measure of the density of the fiber. One denier is 1 g/9,000 m, so 1 denier = 0.1111 tex.

While some natural polymers produced “natural” fi bers, fibers from synthetic and regenerated

natural polymers are generally produced using one of the spinning processing techniques. Three
spinning processes are generally employed in the large-scale commercial production of fi bers. The

first produces fiber from the melted polymer-melt spinning. The other two techniques form fi bers
from concentrated polymer solutions—dry and wet spinning. Figure 18.3 illustrates the essentials
of these three spinning techniques. Table 18.4 is a listing of the most common polymers made into

fibers by these three processes.
18.3.2 MELT SPINNING
Melt spinning was developed in the 1930s. In melt spinning, the polymer is melted or extruded,

clarifi ed by filtration, and pumped through a die having one or more small holes. The die is called
a spinneret. The number, shape, and size of the hole can vary considerably. The number of holes
ranges from several holes to several thousand holes.

TABLE 18.2
Generic Names for Synthetic Fibers According to the ISO and FTC
ISO FTC
Acetate Acetate
Acrylic Acrylic
Aramid Aramid
Chlorofi ber Vinyon/Saran
Cupro/viscose/modal/deacetylated acetate Cupra/rayon
Elastane Spandex
Glass Glass
Modacrylic Modacrylic
Nylon/polyamide Nylon/polyamide
Polyester Polyester
Polyethylene/polypropylene–polyolefi n olefi n Vinylal/vinal

TABLE 18.3
Global Production of Fibers by Fiber Type (2005)
Fiber Type Global Production Million Tons Global Production Percentage
Cellulosic 2.0 6
Acrylic 2.7 8
Nylon 3.9 11
Olefi n 5.9 17
Polyester 21 58

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