Cellophane is a thin, flexible, synthetic material. It is made from cellulose, a substance in the walls of plant cells (see Cellulose ). Most cellophane is coated with special chemicals to make it airproof and moisture-resistant. These chemicals also make cellophane heat sealable—that is, they enable cellophane to be sealed to itself and to certain other materials through the application of heat and pressure.
Most cellophane is used to package products that require protection from air and moisture to remain fresh. Such products include baked goods, candy, and cigars. Most cellophane is transparent and colorless and is about 1/1,000 inch (0.03 millimeter) thick. It is also flammable.
How cellophane is made.
Cellulose manufacturers begin by chemically removing cellulose from wood pulp and mixing it with with sodium hydroxide (also called caustic soda, or lye). This mixture is aged and treated with carbon disulfide to create a thick, sticky liquid called viscose. After the viscose has been aged and filtered, manufacturing machinery extrudes (pushes) it through a long, narrow slit, forming it into a thin liquid sheet. This sheet is immediately treated with sulfuric acid, which hardens it into cellophane. Various chemical processes remove impurities and make the cellophane flexible. The product is then dried and wound onto rolls.
History.
A Swiss chemist named Jacques E. Brandenberger discovered cellophane in 1908, when he sprayed viscose on a tablecloth he was trying to make stain-resistant. He found he could peel the coating from the cloth in the form of a thin, transparent sheet. In 1911, Brandenberger designed a machine to produce the material. In 1927, the DuPont Company developed coatings to make cellophane moisture-resistant and heat-sealable. Since the 1960’s, polyesters and other film materials made from petroleum have replaced cellophane for most packaging.
