Editing Argon (section)

===Preservative===
[[File:CsCrystals.JPG|thumb|A sample of [[caesium]] is packed under argon to avoid reactions with air]]
Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the [[E numbers|European food additive code]] E938). Aerial oxidation, hydrolysis, and other chemical reactions that degrade the products are retarded or prevented entirely. High-purity chemicals and pharmaceuticals are sometimes packed and sealed in argon.<ref name="pmid17099243">{{cite journal |vauthors=Ilouga PE, Winkler D, Kirchhoff C, Schierholz B, Wölcke J|date=November 2007 |title=Investigation of 3 industry-wide applied storage conditions for compound libraries|journal=Journal of Biomolecular Screening|volume=12 |issue=1 |pages=21–32 |doi=10.1177/1087057106295507|pmid=17099243 |doi-access=free }}</ref>

In [[winemaking]], argon is used in a variety of activities to provide a barrier against oxygen at the liquid surface, which can spoil wine by fueling both microbial metabolism (as with [[acetic acid bacteria]]) and standard [[redox]] chemistry.

Argon is sometimes used as the propellant in [[aerosol]] cans.

Argon is also used as a preservative for such products as [[varnish]], [[polyurethane]], and paint, by displacing air to prepare a container for storage.<ref>Zawalick, Steven Scott "Method for preserving an oxygen sensitive liquid product" {{US patent|6629402}} Issue date: 7 October 2003.</ref>

Since 2002, the American [[National Archives]] stores important national documents such as the [[United States Declaration of Independence|Declaration of Independence]] and the [[United States Constitution|Constitution]] within argon-filled cases to inhibit their degradation. Argon is preferable to the helium that had been used in the preceding five decades, because helium gas escapes through the intermolecular pores in most containers and must be regularly replaced.<ref>
{{cite web
 |url=https://www.archives.gov/press/press-kits/charters.html#pressrelaese1
 |title=Schedule for Renovation of the National Archives Building
 |access-date=7 July 2009
}}</ref>