Pros and Cons of Plastic Storage Containers

What's safe for food is also usually safe for artifacts.

When considering plastic storage boxes, be sure to look for polypropylene or polyethylene. Both of these plastics have been tested as safe in conservators’ artificial aging scenarios (oddy tests). Polypropylene usually has the initials “PP” on the base under the recycling symbol. Polyethylene products contain a “PE” in addition to other letters (i.e. HDPE, LDPE).

Pros:

  • Poly boxes offer flood protection.
  • Poly boxes create a micro-climate that will drastically slow changes in RH (moisture equilibration).
  • Poly boxes are often available in clear, allowing for increased visibility of interior artifacts and humidity indicator strips.
  • Poly boxes allow for a desiccated micro-environment with the use of silica gel—especially helpful in cases where metal is corroding.
  • While all boxes deter insects, only poly boxes keep rodents out.
  • Depending on type, size, and source, poly boxes can be less expensive than archival board boxes.

Cons:

  • Poly boxes can store and retain acidity and do not contain buffering agents to counteract acidity.
  • If RH level is high in the micro-climate, risks intensify.
  • Larger size poly boxes are not made or sold for preservation purposes and may contain additives that are potentially harmful for artifact preservation.
  • Depending on type, size, and source, poly boxes can be more expensive than archival board boxes.
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About collectionsconversations

This blog will contain posts from the C2C project staff on a variety of topics related to collections care and disaster preparedness. Enjoy the posts and let us know if you would like additional information or have a topic you would like for us to address.

Posted on January 27, 2012, in collections access, collections care, collections management, disaster preparedness, storage and tagged , , , . Bookmark the permalink. 3 Comments.

  1. What would be your opinion on storing an antique silk wedding dress in a PP or PE box (along with unbuffered tissue) versus an acid-free textile storage box? I work for a small museum, and the PP/PE box may be a cheaper alternative for our limited budget if it’s a safe storage option.
    By the way, just found this blog, and I think it’s a great idea! I will be returning regularly 🙂

    • I feel pretty confident recommending that type of plastic box. I’ve corresponded with environmental conservators at IPI and conservator Marc A. Williams about poly storage boxes and think they’re a really good solution–especially in cases where there is little RH control or possible rodents. I’d keep a humidity indicator card inside the box, if it’s clear and in a visible position, you can check the RH without opening the box. Also, try to pack the textile artifact in moderate RH conditions (40-50%). If it’s excessively humid when packing, there is a danger that the plastic would trap excess moisture the textile holds. The PP will keep ambient RH swings from affecting the microclimate within. Also, light easily damages silk, so that’s a consideration with clear PP, depending on where you would keep the box. –Adrienne Berney

  2. Thank you so much for your advice. I really appreciate it!

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