Cellophane

Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, and bacteria makes it useful for food packaging. Cellophane is in many countries a registered trade mark of Innovia Films Ltd, Cumbria, UK. Cellulose from wood, cotton, hemp, or other sources is dissolved in alkali and carbon disulfide to make a solution called viscose, which is then extruded through a slit into a bath of dilute sulphuric acid and sodium sulphate to reconvert the viscose into cellulose. The film is then passed through several more baths, one to remove sulphur, one to bleach the film, and one to add glycerine to prevent the film from becoming brittle. A similar process, using a hole (a spinneret) instead of a slit, is used to make a fibre called rayon. Chemically, cellophane, rayon and cellulose are polymers of glucose and contain the chemical elements carbon, hydrogen, and oxygen.

History

Cellophane emerged from a series of efforts conducted during the late 19th century to produce artificial materials by the chemical alteration of cellulose, a natural polymer obtained in large quantities from wood pulp or cotton linters. In 1892 English chemists Charles F. Cross and Edward J. Bevan patented viscose, a solution of cellulose treated with caustic soda and carbon disulphide. Viscose is best known as the basis for the man-made fibre rayon, but in 1898 Charles H. Stearn was granted a British patent for producing films from the substance.

Cellophane was invented by Swiss chemist, Jacques E. Brandenberger while employed by Blanchisserie et Teinturerie de Thaon. In 1900, inspired by seeing a wine spill on a restaurant's tablecloth, he decided to create a cloth that could repel liquids rather than absorb them. His first step was to spray a waterproof coating on to fabric, and he opted to try viscose. The resultant coated fabric was far too stiff, but the clear film easily separated from the backing cloth, and he abandoned his original idea as the possibilities of the new material became apparent.

By 1908, Brandenberger developed the first machine for the manufacture of transparent sheets of regenerated cellulose. By 1912, Brandenberger was making a saleable thin flexible film used in gas masks. Brandenberger coined the term cellophane by combining cellulose with diaphane, the French word for “translucent.” In the United States, the first customer for Cellophane film was Whitman's candy company, who used the the film to wrap their chocolates. Whitman's imported the product from France until 1924, when Dupont started manufacturing and selling the film.

Development in the Invention of the Cellophane

In 1917 Brandenberger assigned his patents to La Cellophane Societe Anonyme and joined that organization.

On December 26, 1923, an agreement was executed between the DuPont Cellophane Company and La Cellophane. La Cellophane licensed to the DuPont Cellophane Company the exclusive rights to its United States cellophane patents, and granted to the DuPont Cellophane Company the exclusive right to make and sell in North and Central America using La Cellophane's secret processes for cellophane manufacture. In exchange, the DuPont Cellophane Company granted to La Cellophane the exclusive rights for the rest of the world the use of any cellophane patents or processes DuPont Cellophane Company might develop.

Cellophane had it's limitation as even though it was waterproof, it was not moisture proof - it held water but was permeable to water vapour. It was therefore unsuited to packaging products that required moisture proofing. Du Pont hired chemist William Hale Charch, who spent three years developing a nitrocellulose lacquer that, when applied to Cellophane, made it moisture proof. Following the introduction of moisture-proof Cellophane in 1927, the material's sales tripled between 1928 and 1930, and in 1938, Cellophane accounted for 10% of Du Pont's sales and 25% of its profits.

Role of the Invention of the Cellophane in the development of Human Life

• It was widely used for packaging a variety of food items which were susceptible to damage.

• It became a base for self-adhesive tapes as Sellotape and Scotch Tape, a semi-permeable membrane in a certain type of battery, as dialysis tubing (Visking tubing) and as a release agent in the manufacture of fibreglass and rubber products.

• Cellulose film has been manufactured continuously since the mid-1930s and is still used today.