the fiber manufacturing processmanufactured fiber—any fiber derived by a process of manufacture from a substance that at any point in the process is not a fiber•generic names—refers to family of manufactured or synthetic fibers with similar chemical composition•trade names—companies’ names for fibers used for promotion & marketing

two types of manufactured fibers—•regenerated•synthetic

impact has far exceeded original predictions—caused tremendous changes in the way people live

the fiber manufacturing process

fiber spinning

raw material is:•natural product—cellulose or protein•synthetic polymer dissolved in liquid chemicals and made into a spinning solution (dope)

all manufactured-fiber spinning processes are based on these 3 steps:1.preparing a viscous dope or melt2.forcing or extruding dope or melt through opening in spinneret to form a fiber3.solidifying the fiber by coagulation, evaporation or cooling

fiber spinning

fiber spinning

fiber spinning

fiber modifications

there are 5 general ways that a fiber modification can be made:1.the size and shape of the spinneret can be changed to produce fibers of different sizes and shapes2.the fiber’s molecular structure and crystallinity can be changed to enhance fiber durability3.other compounds can be added to the polymer or dope to enhance fiber performance4.the spinning process can be modified to alter fiber characteristics5.in a more complex modification, two polymers can be combined as separate entities within a single fiber or yarn

fiber modifications—spinneret

changing fiber size is a common modification—simplest way is changing size of spinneret opening

macrofiber: denier greater than 1.0microfiber: denier less than 1.0ultrafine fibers: less than 0.3 dpfnanofibers: fibers with cross sections measuring less than 1,000 nanometers (human hair 80,000 nm)

macro & microfibers currently used in apparel and interior applicationsnanofibers used in protective apparel, safety harnesses & technical/medical filtration

fiber modifications—fiber shape

changing cross-sectional shape is easiest way to alter a fiber’s mechanical & aesthetic properties—usually by changing shape of spinneret hole

many shapes possible: flat, trilobal, quadrilobal, pentalobal, triskelion, cruciform, cloverleaf, Y, T

trilobal widely used in nylon & polyester—beautiful silklike hand, sheen & color, subtle opacity, soil-hiding capacity, bulk without weight, wicking, crush resistance, & good textured crimp

multilobal fibers improve hydrophilic, wicking and moisture management properties

fiber modifications—molecular structure

manufacturers can change molecular structure for specific end uses:•high-tenacity fibers—modification of polymer to increase polymerization•low-piling fibers—slightly reduced molecular weight of polymer chains•binder staple—when mixture is heated, bonds regular fibers together•low-elongation—changing the balance of tenacity and extension (useful in blends)•shape memory fibers—designed to conform to specific shape when specific stimuli (heat, light, etc…) are activated

fiber modifications—additives

delustering:titanium oxide—a white pigment—is added to spinning solution before fiber is extruded; particles of pigment absorb light…weakens fiber

solution dyeing:addition of colored pigments or dyes to spinning solution; provides color permanence; cost more per pound than other fibers

fiber modifications—additives

whiteners & brighteners:added to spinning solution to make fibers look whiter & resist yellowing; reflect more blue light & masks yellowing

cross-dyeable fibers:incorporates dye-accepting chemicals into molecular structure

antistatic fibers:fiber is made wettable by adding an antistatic compound to the fiber-polymer raw material

fiber modifications—additives

sunlight-resistant fibers:nitrogenous compounds added to dope to stabilize reaction between UV light and fiber or dye; carefully selected for specific fiber-dye combination

flame-resistant fibers:produced by changing polymer structure or by adding flame-retardant compounds to spinning solution

fiber modifications—additives

antibacterial fibers:chemical compounds that kill or discourage growth of bacteria and other microbes are incorporated in spinning solution prior to extrusion or during spinning

may require frequent washing to remove microbial debris and allow additive to work on living microbes

fiber modifications—complex

fiber modifications that provide comfort and improve human performance are important in today’s industry

more efficient materials produce lighter-weight, more comfortable products•manage moisture•wick perspiration away from skin•provide warmth or insulation•decrease friction & increase speed•protect from wind, rain or snow

http://www.youtube.com/watch?v=OnYaQgdazEQ

environmental concerns & sustainability

use only a small fraction of the by-products of the production of gasoline and fuel oils

fibers like nylon, polyester & olefin produced from natural gases or butadiene (by-product of refining crude oil)

significant efforts have been made by fiber producers to minimize negative environmental aspects of fiber production:•government regulations•concern for safety•economic necessity of reducing costs•public image concerns

environmental concerns & sustainability

natural degrading of fiber?with current landfill practices, natural fibers do not even degrade on their own

recycling of synthetic fibers very important to industry—polyester produced from preconsumer and postconsumer waste include a range of products from underwear to carpeting

“100% recyclable products” will be taken back by manufacturer and recycled when disposed of by consumer

manufactured fiber consumption

in 1928 manufactured fibers accounted for 5% of fiber consumption in the U.S…

now•64% world textile consumption•83% U.S. textile consumption

consumers continue to value natural fibers, but in many end uses manufactured fibers are clearly superior

manufactured vs. natural fibers

manufactured fibers provide performance options not possible with natural fibers

incredibly versatile and modified to meet wide range of performance expectations

can be produced quickly in the quantity and quality needed to meet market demand