Saran is a
trade name
A trade name, trading name, or business name, is a pseudonym used by companies that do not operate under their registered company name. The term for this type of alternative name is a "fictitious" business name. Registering the fictitious name w ...
used by
S.C. Johnson & Son, Inc. for a
polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bo ...
food wrap. The Saran trade name was first owned by
Dow Chemical for
polyvinylidene chloride
Polyvinylidene chloride, or polyvinylidene dichloride (PVDC), is a homopolymer of vinylidene chloride.
History
Ralph Wiley accidentally discovered polyvinylidene chloride polymer in 1933. He, then, was a college student who worked part-time at D ...
(PVDC), along with other
monomer
In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization.
Classification
Mo ...
s. The formulation was changed to the less effective polyethylene in 2004 due to the chlorine content of PVDC.
Since its accidental discovery in 1933, polyvinylidene chloride has been used for a number of commercial and industrial products. When formed into a thin plastic film, the principal advantages of polyvinylidene chloride, when compared to other plastics, are its ability to adhere to itself and its very low
permeability to water vapor, flavor and aroma molecules, and oxygen. This oxygen barrier prevents food spoilage, while the film barrier to flavor and aroma molecules helps food retain its flavor and aroma.
History
![Saran Wrap 02](https://upload.wikimedia.org/wikipedia/commons/8/8d/Saran_Wrap_02.JPG)
Polyvinylidene chloride (PVDC) was discovered at
Dow Chemical Company
The Dow Chemical Company, officially Dow Inc., is an American multinational chemical corporation headquartered in Midland, Michigan, United States. The company is among the three largest chemical producers in the world.
Dow manufactures plastic ...
(Michigan, United States) in 1933 when a lab worker, Ralph Wiley, was having trouble washing beakers used in his process of developing a dry-cleaning product. It was initially developed into a spray that was used on US fighter planes and, later, automobile upholstery, to protect them from the elements. Dow Chemical later named the product Saran and eliminated its green hue and offensive odor.
In 1942, fused layers of original-specification PVDC were used to make woven mesh ventilating insoles for newly developed
jungle or tropical combat boots made of rubber and canvas.
[Risch, Erna, ''The Quartermaster Corps'', Washington, D.C.: Office of the Chief of Military History, Dept. of the Army (1953), pp. 108-109][Kearny, Cresson H. (Maj), ''Jungle Snafus...And Remedies'', Oregon Institute of Science and Medicine (1996), pp. 179-183][''Report on Orinoco-Casiquiare-Negro Waterway: Venezuela-Colombia-Brazil'', Volume 4, Washington, D.C.: U.S. Army Corps of Engineers, U.S. Office of Inter-American Affairs (July 1943)] These insoles were tested by experimental Army units in jungle exercises in Panama, Venezuela, and other countries, where they were found to increase the flow of dry outside air to the insole and base of the foot, reducing blisters and tropical ulcers.
The PVDC ventilating mesh insole was later adopted by the United States Army for standard issue in its M-1945 and M-1966 Jungle Boots.
In 1943, Ralph Wiley and his boss, John Reilly, both employed by Dow Chemical Company, completed the final work needed for the introduction of PVDC, which had been invented in 1939. PVDC monofilaments were also extruded for the first time. The word ''Saran'' was formed from a combination of John Reilly's wife's and daughter's names, Sarah and Ann Reilly.
In 1949, Dow introduced Saran Wrap, a thin, clingy
plastic wrap
Plastic wrap, cling film, Saran wrap, cling wrap, Glad wrap or food wrap is a thin plastic film typically used for sealing food items in containers to keep them fresh over a longer period of time. Plastic wrap, typically sold on rolls in boxe ...
that was sold in rolls and used primarily for wrapping food. It quickly became popular for preserving food items stored in the refrigerator. Saran Wrap was later acquired by
S. C. Johnson & Son.
After the end of the Vietnam War, the U.S. military phased out PVDC insoles in favor of Poron®, a microcellular urethane, for its jungle and combat boots.
However, the British Army continues to use PVDC insoles in its combat boots, primarily because of its insulating properties.
Formulation change to polyethylene
Today's Saran Wrap is no longer composed of PVDC in the United States, due to cost,
processing difficulties, and environmental concerns with halogenated materials,
[ and is now made from ]polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including bo ...
. However, polyethylene has a higher oxygen permeability, which in turn affects food spoilage prevention. For example, at 23 °C and 95% relative humidity polyvinylidene chloride has an oxygen permeability of 0.6 cm3 μm m−2 d−1 kPa−1 while low-density polyethylene
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its ...
under the same conditions has an oxygen permeability of 2000 cm3 μm m−2 d−1 kPa−1. For that reason, packaging for the meat industry still may use PVDC-containing films, as a barrier layer.[ ]
References
External links
*
"Saran Wrap - The History of PVDC"
(from About.com
Dotdash Meredith (formerly About.com) is an American digital media company based in New York City. The company publishes online articles and videos about various subjects across categories including health, home, food, finance, tech, beauty, ...
)
{{SCJohnson
Plastics
Packaging materials
Food preparation utensils
Synthetic fibers
Kitchenware brands
S. C. Johnson & Son brands
Dow Chemical Company
Brand name materials
Products introduced in 1933