Cellulose acetate

Cellulose acetate (also known as zyl or zylonite),[1] first prepared in 1865, is the acetate ester of cellulose. Cellulose acetate is used as a film base in photography, as a component in some adhesives, and as a frame material for eyeglasses;[1] it is also used as a synthetic fiber and in the manufacture of cigarette filters and playing cards.

Contents

History

Paul Schützenberger discovered that cellulose could react with acetic anhydride to form cellulose acetate in 1865 but the use of chloroform to make it soluble was expensive and in 1904 George Miles, and American chemist[2], discovered that hydrolyzed cellulose acetate is soluble in more solvents like acetone. German chemist Eduard Schweizer discovered that tetraaminecopper dihydroxide could dissolve cellulose.[3]

Acetate was first introduced in 1904, when Camille Dreyfus and his younger brother Henri, did chemical research and development in a shed in their father's garden in Basel, Switzerland. Inasmuch as their father was interested in a chemical factory, his influence was probably a factor in their choice of careers. And since Basel was a center of the dyestuffs industry, it was natural that their first achievement should be the development of synthetic indigo dyes. In search of a field that offers really limitless potentialities, they deliberately selected that of cellulose acetate products, including fibers for textile use.[4]

For five years, the Dreyfus brothers studied and experimented in a logical, systematic manner in Switzerland and France. By 1910, they had perfected acetate lacquers and plastic film and opened a factory in Basel capable of producing about three tons a day. This was largely sold to the celluloid industry in France and Germany, and to Pathe Fréres in Paris for non-flammable motion picture film base. A small but constantly growing amount of acetate lacquer, called "dope", was sold to the expanding aircraft industry to coat the fabric covering wings and fuselage.[4]

After some twenty-odd thousand separate experiments, by 1913, the brothers produced excellent laboratory samples of acetate continuous filament yarn. In 1918 the American Cellulose & Chemical Manufacturing Company was founded in New York by the Dreyfus brothers.

The outbreak of World War I postponed completion of development leading to successful commercial production until 1921. The war, of course, necessitated rapid expansion of the Basel factory which terminated its trade with Germany and exclusively supplied the Allied Governments with acetate "dope" for military aircraft.[4]In 1927 the American Cellulose & Chemical Manufacturing Company name was changed to the Celanese Corporation of America[5].

In 1849 Mazzucchelli Spa. opened in north of Italy in Castiglione Olona a town near Varese, Como and Milan. The founder Santino Mazzucchelli and his son Pompeo begin working Cellulose nitrate sheets in the late 1800. The idea was to transform the sheets in to combs, brushes, bottons and hair ornaments. This entrepreneurs were able to establish a company that would influence the development of bioplastic material world wide til today. Mazzucchelli grew to become the largest producer of Celluloid Acetate sheets and Cellulose Nitrate sheets worldwide. Today this warm and aesthetically pleasing material is used mostly for making the frames for eyeglasses, followed by hair ornaments, jewellery, stationary and other accessories. The history of Mazzucchelli 1849 Spa. is fascinating being one of the few family company that lasted for 6 generations. The family is still involved in the business and it continues to influence the bioplastic manufactring development in Europe, USA and Asia. Through the year many tests were done and many patterns were created with acetate sheets the most famous is the Tortoise shell look made exclusively by Mazzucchelli.

In November 1914, the British Government invited Dr. Camille Dreyfus to come to England to manufacture acetate "dope". The "British Cellulose and Chemical Manufacturing Co" was set up. At the end of World War I, the British Government canceled all contracts and the company changed to produce acetate fibers. In 1918 the company name was changed to British Celanese Ltd.

In 1917, the War Department of the United States Government invited Dr. Dreyfus to establish a similar factory in the US after their entry into war. After about six weeks, a contract was negotiated for sale of acetate "dope" to the War Department and a plant site was sought. Dr. Dreyfus and his associates started construction of the American company at Cumberland, Maryland in 1918, but the war was over before the plant could be completed. The business with the Government was completed in due time, construction of the plant continued, the early nucleus of the management began to assemble, and the organization in England completed development of the first commercially successful acetate textile yarn. In England, in 1912, the British company produced the first commercial cellulose acetate yarn. The yarn was sold primarily for crocheting, trimming, and effect threads and for popular-priced linings.[4]

The first yarn spun in America was on Christmas Day, 1924, at the Cumberland, Maryland Plant. The first yarn was of fair quality, but sales resistance was heavy, and silk associates worked zealously to discredit acetate and discourage its use. Acetate became an enormous success as a fiber for moiré because its thermoplastic quality made the moiré design absolutely permanent. The same characteristic also made permanent pleating a commercial fact for the first time, and gave great style impetus to the whole dress industry.[4]

This was a genuine contribution. The mixing of silk and acetate in fabrics was accomplished at the beginning and almost at once cotton was also blended, thus making possible low-cost fabrics by means of a fiber which then was cheaper than silk or acetate. Today, acetate is blended with silk, cotton, wool, nylon, etc. to give to fabrics an excellent wrinkle recovery, good left, handle, draping quality, quick drying, proper dimensional stability, cross-dye pattern potential, at a very competitive price.[4]

Acetate fiber and triacetate fiber

Acetate and triacetate are mistakenly referred to as the same fiber; although they are similar, their chemical compounds differ. Triacetate is known as a generic description or primary acetate containing no hydroxyl group. Acetate fiber is known as modified or secondary acetate having two or more hydroxyl groups. Triacetate fibers, although no longer produced in the United States, contain a higher ratio of acetate-to-cellulose than do acetate fibers[1].

Cellulose acetate film

Cellulose acetate film was introduced in 1934 as a replacement for the cellulose nitrate film stock that had previously been standard. When exposed to heat, moisture or acids in the film base begin to deteriorate to an unusable state, releasing acetic acid with a characteristic vinegary smell, causing the process to be known as "vinegar syndrome." Acetate film stock is still used in some applications, such as camera negative for motion pictures. Since the 1980s, polyester film stock (sometimes referred to under Kodak's trade name "ESTAR Base") has become more commonplace, particularly for archival applications. Acetate film was also used as the base for magnetic tape, prior to the advent of polyester film.

Cellulose acetate computer tape

Cellulose acetate magnetic tape was introduced by IBM in 1952 for use on their IBM 726 tape drive in the IBM 701 computer. It was much lighter and easier to handle than the metal tape introduced by UNIVAC in 1951 for use on their UNISERVO tape drive in the UNIVAC I computer. In 1956 cellulose acetate magnetic tape was replaced by the more stable PET film magnetic tape for use on their IBM 727 tape drive.

Fiber

Cellulose acetate fiber is one of the earliest synthetic fibers and is based on cotton or tree pulp cellulose ("biopolymers"). These "cellulosic fibers" have been replaced in may applications by cheaper petro-based fibers (nylon and polyester) in recent decades.

It was invented by two Swiss brothers, Doctors Camille and Henri Dreyfus, who originally began chemical research in a shed behind their father's house in Basel, Switzerland. In 1905, Camille and Henri developed a commercial process to manufacture cellulose acetate. The Dreyfus brothers initially focused on cellulose acetate film, which was then widely used in celluloid plastics and film. By 1913, Camille and Henri's studies and experiments had produced excellent laboratory samples of continuous filament acetate yarn. In 1918 acetate fiber was first manufactured in quantity at the British Celanese plant in Spondon, Derbyshire. In 1924, the first commercial acetate filament was spun in the United States and trademarked as Celanese.

Trade names for acetate include Acele, Avisco, Celanese, Chromspun and Estron.[6]

Fiber properties

Acetate is a very valuable manufactured fiber that is low in cost and has good draping qualities. Properties of acetate have promoted it as the “beauty fiber”[1]. Acetate is used in fabrics such as satins, brocades, and taffetas to accentuate luster, body, drape and beauty.

Acetate usually requires dry cleaning.

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 thereby will the quality of the cellulose acetate sometimes be damaged. 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]

Acetate fiber characteristics

Major industrial acetate fiber uses

See also

References

  1. ^ a b frame material
  2. ^ acetate-Retrieved 2011-10-10
  3. ^ rayon development- Retrieved 2011-10-10
  4. ^ a b c d e f Peter John Turnbull Morris, "The American Synthetic Rubber Research Program", Pennsylvania Press, ISBN 0-8122-8207-8, Full Text Online, page 258
  5. ^ Celanese Corporation of America-Retrieved 2011-10-10
  6. ^ trade names

External links