Preservative
Argon is used to displace oxygen- and moisture-containing air in packaging material to extend the shelf-lives of the contents (argon has the European food additive code of E938). Aerial oxidation, hydrolysis, and other chemical reactions which degrade the products are retarded or prevented entirely. Bottles of high-purity chemicals and certain pharmaceutical products are available in sealed bottles or ampoules packed in argon.
In winemaking, argon is used in a variety of activities to provide a barrier against oxygen at the liquid's surface, which can spoil wine by fueling both microbial metabolism (such as with acetic acid bacteria) and standard redox chemistry.
Argon is also available in aerosol-type cans, which may be used to preserve compounds such as varnish, polyurethane, paint, etc. for storage after opening.[35]
Since 2002, the American National Archives stores important national documents such as the Declaration of Independence and the Constitution within argon-filled cases to inhibit their degradation. Using argon reduces gas leakage, compared with the helium used in the preceding five decades