Acetate Fiber

Acetate Fiber

1. Acetate Fiber
Federal Trade Commission Definition for Acetate Fiber: A 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.
Acetate and triacetate
The term acetate fibres is used to describe fibres made from cellulose acetate. The difference between
acetate and triacetate fibres lies in the number of the cellulose hydroxyl groups that are acetylated. For
acetate fibres the number lies between 75% and 92%, for triacetate fibres it is more than 92%.
Acetate, which is properly called cellulose acetate (chemically di-acetate or secondary acetate)
was first made by Paul Schutzenberger in 1869
Basic Principles of Acetate Fiber Production:
1. Purified cellulose from wood pulp or cotton linters
2. Mixed with glacial acetic acid, acetic anhydride, and a catalyst
3. Aged 20 hours- partial hydrolysis occurs
4. Precipitated as acid-resin flakes
5. Flakes dissolved in acetone
6. Solution is filtered
7. Spinning solution extruded in column of warm air. Solvent recovered
8. Filaments are stretched and wound onto beams, cones, or bobbins ready for use
[1]

9. Filaments are then spun into fiber

Acetate is derived from cellulose by reacting purified cellulose from wood pulp with acetic acid and
acetic anhydride in the presence of sulfuric acid. It is then put through a controlled, partial hydrolysis to
remove the sulfate and a sufficient number of acetate groups to give the product the desired properties.
The anhydroglucose unit, is the fundamental repeating structure of cellulose, has three hydroxyl groups
which can react to form acetate esters. The most common form of cellulose acetate fiber has an acetate
group on approximately two of every three hydroxyls. This cellulose diacetate is known as secondary
acetate, or simply as “acetate”.
After it is formed, cellulose acetate is dissolved in acetone for extrusion. As the filaments emerge from
the spinneret, the solvent is evaporated in warm air (dry spinning), producing fine filaments of cellulose
acetate.

2. Chemistry of acetate fiber:

3. Physical properties of acetate:

Acetate filament: It is in broken strands. The length relies on the capacity of winding mechanism.
Modern winders hold many pounds of yarns with one or two knots per cone.
Acetate staple fibre: It can be cut into desired length. Commonly desired lengths are 1.50, 2, 2.50 and 3
inches till 7 inches for silk industries.
Fineness: The diameter of the strand ranges from 1.5 to 4.1 deniers for filaments and 1.5 to 20 deniers
for staple fibres.
Appearance and Color: The luster and color may be as desired. Bright luster may be received by lesser
twist. Staple are not as lustrous as filaments. Various shades from paler tints to heavy may be acquired
as they are the whitest fibres.
Density: The density ranges from 1.25 to 1.33 gm per cc. relying on the methods of measurement and
moisture at the time of making.
Absorption: The hygroscopicity is corresponding to cellulose but absorption is much less since hydroxyl
groups are removed by acetyl groups.
Tenacity: The wet strength is 65% of dry strength. The fibres can be changed in tenacity by the
manufacturers.
Elasticity: Under general situations, elastic recovery of fibre is completed within few seconds. But for
longer time and heavier load creep, deterioration or clearage occurs.
Thermal properties: It is a thermoplastic material. With temperature it becomes soft. It can be ironed at
the temperature up to 250
0
F. Above this sticking and melting occurs.
Conductivity: It is a perfect insulator. The static electricity is created by friction.

Chemical properties of acetate:

Effect of alkalis: It is stable to water even at boil and can withstand soap solutions and alkalis at normal
temperature.
Effect of acids: It is unaffected by thin solution but is attacked by strong acids. The degradation of
molecules occurs and the chain breaks.
Effect of oxidizing agents: Mild oxidizing agents may be utilized i.e. chlorine is old and mild peroxide.
Effect of organisms: It is resistant to attack by bacteria and mildew but it is attacked by moth which
makes holes in fabric.

Acetate Fiber Characteristics
 Luxurious feel and appearance
 Wide range of colors and lusters
 Excellent drapability and softness
 Relatively fast drying
 Shrink, moth and mildew resistant

4. Major industrial acetate fiber uses
 Apparel: buttons, sunglasses, linings, blouses, dresses, wedding and party attire, home
furnishings, draperies, upholstery and slip covers.
 Industrial uses: cigarette and other filters, ink reservoirs for fiber tip pens.
 High absorbency products: diapers and surgical products.
 The original Lego bricks were manufactured from cellulose acetate from 1949 to 1963.
 Award Ribbon: Rosettes for equestrian events, dog/cat shows, corporate awards, advertising
and identification products all use cellulose acetate ribbon.
 KEM brand playing cards, used at the World Series of Poker and in many poker rooms at major
casinos, are made of cellulose acetate. Italian playing card manufacturer Modiano also makes a
line of playing cards made of "acetate," though it is unclear whether this is true cellulose
acetate.