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CHAPTER 8- POLYESTER FIBERS - First produced by DuPont plant; Dacron®; US 1953 - “manufactured fiber in which fiber-forming substance is any long chain synthetic polymer composed of 85% by weight of an ester of substituted aromatic carboxylic acid, including but not restricted to substituted terephthalate units or parasubstituted hydroxybenzoate units” –FTC Manufacture - Starting materials are: organic acid and an alcohol, both derived from petroleum o Most commonly used acid is terephthalic acid or its dimethyl ester - Processes used vary for diff. polyesters - PET—polyethylene terephthalate o Formed by reaction of terephthalic acid and ethylene glycol o At high temps under vacuum the two compounds react, with an antimony catalyst, in series of steps to build up polymer chain of considerable length o Direct esterification —most producers now begin with the acid, reacting it with ethylene glycol o Now days the polymerization and spinning steps in one continuous process; polymer produced at high temps and melt is pumped directly to spinnerets o When fiber exits spinneret, they solidify on hitting cool air and wound loosely onto cylinders o Cross sectional shapes can be modified to create fabrics for special purposes Hollow polyesters are made into fiberfill with good insulating qualities Multi-lobed fiber enhance wicking Drawing - Staple fiber: several sets of filaments, each containing 250-3000 filaments, brought together and coiled in large can in preparation for drawing o Yarns then heated and drawn to several times orig. length to orient molecular structure then allowed to relax to release stresses and strains and reduce shrinkage o drawn tow is crimped, dried, and heat-set for stability o tow can now be cut into required staple lengths & baled for sale; usually 38-152 mm (1.5-6 in) in length - Filament yarn: either drawn directly and packaged for sale or wound on bobbins in preparation for draw twisting or draw texturing o Yarn for weaving or knitting or yarn intended for texturing often processed on draw twister that heats and draws fibers and imparts small amt of base twist
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o Addt. Heating and drawing given to high strength industrial yarns in second stage of processing - POY: partially oriented yarns; yielded by high speed spinning processes o Yarns both drawn and textured in same operation—where drawing, texturing, and heat-setting
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  • Fall '08
  • Staff
  • Polymer, Carboxylic acid, Polyester, Polyethylene terephthalate, Polyester Fibers PTT Fibers PBT Fibers PEN Fibers PLA Fibers Polylactic acid Polymers, Fibers PTT Fibers

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