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MANUFACTURED CELLULOSIC FIBERS/ PROTEIN FIBERS Chapter 5
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Identification of Regenerated Fibers Manufactured regenerated fibers: From naturally occurring polymers; regenerated fibers – cannot be used in their natural state, but are chemically processed into a solution that is then extruded through a spinneret Cellulosic: Rayon, lyocell Protein: Azlon – soy silk, silk latte Derivative cellulosic Fibers: chemically changed derivative of cellulose known as esters Acetate, triacetate
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Rayon Production: Wet spun rayon (viscose); high wet modulus (HWM) rayon. Physical structure: Naturally bright Can be solution dyed Regular rayon: Serrated cross section. HWM rayon: Rounder cross section and better performance.
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Chemical Composition and Molecular Arrangement of Rayon Manufactured fiber of regenerated cellulose in which substitutes have replaced not more than 15 percent of the hydrogens of the hydroxyl groups.
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Rayon Properties Physical: Fluid drape, soft hand; control luster, length, diameter. Mechanical: Regular: Weak, especially wet. HWM: Stronger; adequate breaking elongation. Chemical: Absorbent, dyes well, high regain, smooth, soft, good heat & static conductor.
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Rayon Appearance retention: Moderate Regular: poor resiliency, progressive shrinkage HWM: less wrinkling, accepts durable press & dimensional stability finishes, can be merceriz ed Care: Regular: limited washability (wrinkling, loss of sizing, excessive shrinkage) dry clean HWM: greater washability, less wrinkling, shrinkage may be controlled
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Rayon Environmental effects: Similar to other cellulosics. Environmental impact: Tree harvesting, processing of wood pulp, chemicals (acid rain), recycling, water & chemicals in finishing, dry cleaning. Identification: Burns readily, striations, may be crimped.
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Rayon Common modifications: Staple, solution dyed, acid dyeable, cross sections & sizes, high tenacity, HWM, optically brightened, flame retardant, high absorbency. Uses: Apparel, furnishings, industrial (medical, nonwovens, disposables).
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Lyocell Production: Wet spun with the solvent recycled. Physical structure: Staple and filament; rounded cross section, but can be modified. Chemical structure: Manufactured fiber composed of solvent spun cellulose.
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Lyocell Properties Physical: Size, luster, denier related to use. Mechanical: Strong (4.8-5.0 g/d), 18% weaker when wet; adequate breaking elongation; poor resistance to abrasion (fibrillates). Chemical: Good regain (11.5%), no static, soft hand.
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Lyocell Appearance retention: Moderate, dimensional stability moderate. Care: Dry cleaned; unacceptable changes in hand and color if washed in regular cycle.
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Acetate/Triacetate Production: Dry spun; Triacetate no longer produced in the U.S. Physical structure: Staple and filament; lobular cross-section, can be modified.
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Chemical Composition and Molecular Arrangement of Acetate/Triacetate Manufactured fiber in which the fiber forming substance is cellulose acetate. Where, not less than 92% of the hydroxyl groups are acetylated, the term triacetate may be used as a generic description of the fiber; modified cellulose.
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Acetate Properties Physical: Control cross section, luster, denier for end use. Mechanical: Weak, especially when wet; adequate breaking elongation; poor resistance to abrasion. Chemical: Lower regain (acetate 6%, triacetate 3.2%), static, resistant to weak acids, alkalis, and bleach.
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Acetate/Triacetate Appearance retention: Poor resiliency for acetate, better for triacetate. Dimensional stability moderate for both; elasticity low for both. Care: Both can be dry cleaned and are thermoplastic and heat sensitive. Identification: Slight striations. Environmental effects: Resistant to moths, mildew, & bacteria; less than other cellulosics unless sunlight resistant type (SLR).
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Acetate/Triacetate Environmental impact: Tree harvest; processing of wood pulp; solvent reclaimed & reused, dry cleaning. Common fiber modifications: Solution dyed, cross section & fiber sizes, textured, sunlight & weather resistant, flame retardant. Uses: Apparel, furnishings, industrial.
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Other Regenerated Fibers Alginate fiber: Polysaccharides processed from brown seaweed; used for wound dressings. Regenerated protein fibers Soysilk®: from soybean waste; durable, good drape, good comfort; apparel Silk Latte®: from milk protein; soft hand, dyeable; apparel Bamboo: Soft, silky hand; similar to high quality ramie.
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Soy Silk and Bamboo
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Properties (Other Fibers) Identification: Round cross-section, resistant to most organic solvents. Environmental effects: Resistant to moths, similar sunlight resistance to rayon & cotton. Environmental impact: Some made from waste from other industries; small amounts produced. Common fiber modifications: Few at present. Uses: Apparel, furnishings, industrial.
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