Are Polypropylene sheets archival? Not really. These materials are pH neutral, and are the most UV-stable materials we stock. But because these materials are thicker sheets and not glass clear, there is no demand for this material in archival applications, so they have not been tested or certified for archival properties.
If you need a good all-around archival grade film, try our Archival Duralar™ product line, which meets the Library of Congress’ specifications for archival polyester film.