MANUFACTURED CELLULOSIC FIBERS/

PROTEIN FIBERS

Chapter 5

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

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.

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.

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.

Rayon

Appearance retention: Moderate Regular: poor resiliency, progressive shrinkage HWM: less wrinkling, accepts durable press & dimensional stability

finishes, can be mercerizedCare:

Regular: limited washability (wrinkling, loss of sizing, excessive shrinkage) dry clean

HWM: greater washability, less wrinkling, shrinkage may be controlled

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.

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).

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.

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.

Lyocell

Appearance retention: Moderate, dimensional stability moderate.

Care: Dry cleaned; unacceptable changes in hand and color if washed in regular cycle.

Acetate/Triacetate

Production: Dry spun; Triacetate no longer produced in the U.S.

Physical structure: Staple and filament; lobular cross-section, can be modified.

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.

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.

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).

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.

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.

Soy Silk and Bamboo

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.