Transcript Chapter 7 Manufactured Regenerated Fibers

Chapter 5
MANUFACTURED
CELLULOSIC FIBERS/
PROTEIN FIBERS
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
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Cellulosic: Rayon, lyocell
Protein: Azlon – soy silk, silk latte
 Derivative cellulosic Fibers: chemically changed
derivative of cellulose known as esters
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Acetate, triacetate
Rayon
 Production: Wet spun rayon (viscose); high wet
modulus (HWM) rayon.
 Physical structure:
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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 mercerized
 Care:
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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
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 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.