User:KDS4444/Acetate (fiber)

Cellulose acetate fiber, also called diacetate, secondary acetate, or, more commonly, acetate, is one of the earliest synthetic textiles. It is produced from cellulose acetate which itself is based on cotton or tree pulp cellulose (so-called biopolymers-- the fiber which makes up cotton is almost pure cellulose). In recent decades acetate has been replaced in many applications by cheaper and more-durable petroleum-based textiles such as nylon and polyester. Acetate has been marketed under many trade names, including Acele, Avisco, Celanese, Chromspun and Estron among others.

Comparison with other fibers
Acetate shares many similarities both in its production and its finished characteristics with rayon, and at one point manufacturers did not distinguish between the two in garment production. However, rayon is considered a regenerated cellulose fiber whereas acetate is considered a cellulose derived fiber: where rayon is ,,,,, acetate cellulose is no longer considered "regerated" because the polymer formula to produce acetate is acetate ((in the form of cellulose esther) rather than cellulose itself. However, acetate differs from rayon in the employment of acetic acid in its production. The two fabrics are now required to be listed distinctly on garment labels.

Rayon is superior to acetate in that rayon tends to resists heat while acetate is prone to melting. Generally, acetate must be laundered with care either by hand-washing or dry cleaning. Acetate garments will disintegrate when heated in a tumble dryer. The breathable nature of the fabric suits it for use as a lining. Acetate fabric is used frequently in wedding gowns and other bridal attire. Its lustrous sheen and smooth, satiny texture make it an adequate synthetic alternative to silk.

The discovery of cellulose acetate is credited to Paul Schützenberger in 1865. While trying to dissolve cotton in acetic anhydride liquid, he noticed that white flakes of triacetate precipitated out of the solution. However, it wasn't until 1904 that George Miles directly solved the problem of converting triacetate into secondary or "diacetate", which could then be spun. In 1921 British Cellulose Ltd. began the manufacture of acetate in Britain, and a year later Camille Dreyfus (one of the owners of B.C. Ltd) imported the production process to the United States. Initially world demand for acetate grew quickly. however, there has been a precipitous decline in the demand for acetate fiber over the past few decades and it is now rarely encountered.

Acetate fiber, then, currently exists in two forms: triacetate and secondary or diacetate. Both have a lighter volume density than viscose (to which they are closely related) and a similar tenacity/ resistance to breaking when either wet or dry, have very similar wet elongation breaking points (34%-45%), are both considered to have good dimensional stability with some stretch and resistance to shrinkage. The principal differences between the two are that the former is more heat resistant than the latter, and triacetate absorbs about half as much moisture (3.4%-3.5%) as regular secondary acetate (which absorbs 6.5%, about that of cotton). Triacetate is also more resistant to wrinkling that secondary acetate.

It is often important to be able to distinguish between acetate and other manmade but petroleum-based fibers such as polyester and nylon. Like polyester, acetate will burn and melt if heated with a flame. However, the smell of burning polyester is the smell of burning plastic, whereas burned acetate smells like burned wood. Nylon, too, smells like burning plastic.

Fiber properties
Acetate was the first fiber ever invented that melted rather than burned when heated with a match. Acetate begins to break down at 195 F which is well within the heating temperature of most household irons and even clothes dryers. Acetate's tendency to significantly weaken when moistened means it should almost never be machine washed. Triacetate, on the other hand, only decomposes at temperatures that household irons do not reach. Acetate acquires and retains wrinkles easily, while triacetate is more wrinkle resistant. Triacetate can be given permanent heat-set creases and pleats, while acetate cannot. Both acetate and triacetate are mildew and pest resistant. Acetate in particular does not breathe well and has low water-absorbency properties; it becomes uncomfortable to wear in hotter humid weather. Both fabrics are permanently destroyed by contact with nail polish remover or other acetone-containing solvents. Acetate is low in cost and has good draping qualities. It is used in fabrics such as satins, brocades, and taffetas to accentuate luster, body, drape and beauty.


 * Hand: soft, smooth, dry, crisp, resilient
 * Comfort: breathes, wicks, dries quickly, no static cling
 * Drape: linings move with the body linings conform to the garment
 * Color: deep brilliant shades with atmospheric dyeing meet colorfastness requirements
 * Luster: light reflection creates a signature appearance
 * Performance: colorfast to perspiration staining, colorfast to dry cleaning, air and vapor permeable
 * Tenacity: weak fiber with breaking tenacity of 1.2 to 1.4 g/d; rapidly loses strength when wet; must be dry cleaned
 * Abrasion: poor resistance
 * Heat retention: poor thermal retention; no allergenic potential (hypoallergenic)
 * Dyeability: (two methods) cross-dying method where yarns of one fiber and those of another fiber are woven into a fabric in a desired pattern; solution-dying method provides excellent color fastness under the effects of sunlight, perspiration, air contaminants and washing

Production
The Federal Trade Commission definition for acetate fiber is "A manufactured fiber in which the fiber-forming substance is cellulose acetate. Where not less than 92 percent of the hydroxyl groups are acetylated, the term triacetate may be used as a generic description of the fiber."

Acetate is derived from cellulose by deconstructing wood pulp into a purified fluffy white cellulose. In order to get a good product, special qualities of pulps - dissolving pulps - are used. A common problem with these is that the reactivity of the cellulose is uneven, and the quality of the cellulose acetate will sometimes be impacted. The cellulose is then reacted 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 and 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 into a viscous resin for extrusion through spinnerets (which resemble a shower head). As the filaments emerge, the solvent is evaporated in warm air via dry spinning, producing fine cellulose acetate fibers.

First U.S. Commercial Acetate Fiber Production: 1924, Celanese Corporation

Current U.S. Acetate Fiber Producers: Celanese, Eastman Chemical Company

Production method

 * 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 fiber characteristics

 * cellulosic and thermoplastic
 * selective absorption and removal of low levels of certain organic chemicals
 * easily bonded with plasticizers, heat, and pressure
 * acetate is soluble in many common solvents (especially acetone and other organic solvents) and can be modified to be soluble in alternative solvents, including water
 * hydrophilic: acetate wets easily, with good liquid transport and excellent absorption; in textile applications, it provides comfort and absorbency, but also loses strength when wet
 * acetate fibers are hypoallergenic
 * high surface area
 * made from a renewable resource: wood pulp
 * can be composted or incinerated
 * can be dyed, however special dyes and pigments are required since acetate does not accept dyes ordinarily used for cotton and rayon (this also allows cross-dyeing)
 * resistant to mold and mildew
 * easily weakened by strong alkaline solutions and strong oxidizing agents.
 * can usually be washed or dry cleaned; generally does not shrink

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.

Trade names
Cellulose acetate is marketed under various trade names, such as Tenite by the Eastman Chemical Company, zyl and zylonite, Cellon and Rhodoid.

Other Cellulose esters
Related chemical products include cellulose acetate butyrate and cellulose acetate propionate, both of which are used in inks and coatings. The chief difference between these and cellulose acetate is their solubility in a wider range of solvents.