A guide to archival storage products (plastic)...by Paul R

[Ralph P]

Hello all - I was asked by a fellow forum member - Paul R. - to start and pin this thread on the Conservation forum. Overall all the data provided in this thread was put together by Paul and I am just assisting him in getting his data on the forum.

But as I was going through the data I found the information interesting and useful and I think we as a collecting community will also find the data useful. So thanks Paul for taking the time for putting this data together for the forum at large.

[Ralph P]

"Archival quality" generally describes products and materials that are safe for long-term storage and display of paper and collectibles. Art conservation specialists, museum professionals and product suppliers use the following standards and definitions for storage products.

The best-quality plastic storage products use a special type of polyester film, commonly called Mylar, or "archival polyester". You can also store paper collectibles and documents in less expensive Poly storage products. This term often refers to higher quality polypropylene (PP), but is also used for polyethylene (PE). A list of storage product brand names (http://www.dotpattern.com/supplies/s...uct-brands.htm) identifies companies that make mylar and poly products.

Mylar is crystal-clear, very strong, and performs far better than other types of plastic as a barrier against dust, pollution, water vapor and oily fingers. The Library of Congress (http://lcweb.loc.gov/preserv/supply/specs/500-500.html) will use only polyester products (such as Mylar) that "must not contain any plasticizer, surface coatings, UV inhibitors, or absorbents, and be guaranteed to be non-yellowing with natural aging.

Thick, 4-5 mil. mylar storage products are the best for long-term storage of a valuable collection. Economical, 1-2 mil. mylar is used to best display game cards, matchbook covers.

Low Density Polypropylene (PP) and Polyethylene (LDPE) are less expensive than mylar. Storage products made from polypropylene are strong, non-yellowing and less prone to scratching. Clear polyethylene is the least expensive material, acceptable for short-term storage of collectables.

Avoid direct contact between your collection and any products that contain PVC - commonly known as Vinyl (http://www.dotpattern.com/supplies/s...e.html#pvc#pvc) - used in some erasers, 3-ring binders, bubble wrap and adhesive tapes. The ink from artwork and photocopies can 'transfer' onto the surface of (for example) the inside pocket of a vinyl 3-ring binder.

Most important - keep paper and collectibles out of direct sunlight or in an acid-free box. Avoid keeping your collection in the basement or attic where humidity, insects and extreme temperatures can cause damage.

[Ralph P]

Plastics Glossary

cellophane
• crystal-clear
• organic based alternative to polypropylene
• many sizes
• brittle
• grease, oil & moisture resistant
• approved for food use
• heat sealable

[Ralph P]

polyester - any of a group of polymers that consist basically of repeated units of an ester, used especially in making fibers and sheets of plastic film.

Polyethylene Terephthalate (PET) in europe (PETE) is one form of polyester that can be completely recycled into thousands of new products (refer to the "chasing arrows" logo number one).

Uses: soda bottles, leisure suits, x-ray film, video tape and packaging. Recycled into carpet and fiberfill insulation for ski jackets.

[Ralph P]

"Mylar D" and "Melinex 516" are trade names for a special way to make a crystal-clear and strong form of PET plastic, used for true archival-quality storage and conservation products. Mylar is "bi-axially extruded polyester film", which aligns the "chains" of molten plastic both vertically and horizontally, similar to the 'grain' in a sheet of paper.

• Best plastic storage for a valuable collection.
• long-term protection for paper (100 years).
• Mandatory for archival conservation
• Crystal clear and very strong
• very effective barrier against air & moisture
• resistant to grease, oil, heat, oxidation
• chemically inert & non-yellowing
• will not shrink - "dimensionally stable"
• naturally UV resistant
• Can be produced without harmful additives
• generates static electricity which attracts dust
• Mylar is more expensive than "Poly" products

[Ralph P]

polyethylene

• high density polyethylene (HDPE)
• milky white or colored with pigments, waxy feeling.

uses: milk cartons, photographic film canisters, cereal box liners, printed shopping bags

[Ralph P]

low density polyethylene (LDPE)

• Inexpensive plastic for short-term storage.
• Easy to blend & process
• low melting point
• more clarity than polypropylene, but -
• Least rigid material (very flexible)
• low tensile strength
• scratches easily (low hardness)

uses: clear bags for dry cleaning, bread and frozen foods; squeeze bottles, insulation.

[Ralph P]

polypropylene (PP) polymers of propylene

• Quality plastic storage products.
• Lightweight but strong
• non-yellowing
• resistant to chemicals and heat
• crisper than polyethylene (less flexible)
• can be "oriented" (like mylar) for strength & stiffness
• less static than mylar
• less protection from air and moisture than mylar

The best storage products are made without adding vinyl (PVC), plasticizer, softeners or surface treatments.

[Ralph P]

polystyrene (PS)

• clear, hard and brittle
• uses: Compact Disk "gem" cases, toys, house wares, and luggage. Foam cups, plates, egg cartons and insulation.
used for storage boxes

[Ralph P]

"vinyl" (V) or polyvinyl chloride (PVC)

• used for short-term business document storage
• good transparency (clarity)
• chemical and weather resistant
• scratch-proof
• "all PVC polymers are degraded by light and heat, hydrogen chloride is eliminated and oxidation occurs" (http://www.plasticsusa.com/pvc.html)
• retains water (8%)
• "chemicals used to make this type of plastic can react with water vapor to form hydrochloric acid and quickly damage a paper collection."
• Not suitable for archival storage purposes
• uses: "leatherette" fabric, gloves, flying discs, carpet & flooring, pipes, exterior siding, 3-ring binders, bubble wrap.
• not recommended for use with silver.

[J Hardy]

Great info Ralph - I buy all my archival materials from Archival methods. Not cheap but definitely worth it

[Ralph P]

Much appreciate your feedback, the member who deserves all the credit for this thread is Paul R.

Great info Ralph - I buy all my archival materials from Archival methods. Not cheap but definitely worth it

[mfh7200]

Good information,Thanks for posting. This also should be pinned to the top.

[crfraser]

I put my documents and autographs in archival binders purchased from Cohasco. Plastic sleeves covering acid-free paper fillers.

On the fillers, I mount the documents using acid free photo corners. I often print out description on standard computer paper and print photos form the net of the people who signed the docs. These are either mounted on the reverse of the doc or on the same side.

Question - can acid from the standard photo paper or printer paper travel through the acid free filler and affect the document?

Colin

[Dieter3]

Two great sources of materials that I use include:

Conservation Resources International:

http://www.conservationresources.com/

and Atlantic Protective Pouches:

http://www.atlanticprotectivepouches.com/

My method for document protection and storage has been the following:

Mylar/Polyester sleeve with L-Seam - makes inserting documents easier than U-Seam. The document is backed with acid-free paper (the type I use is thicker than most papers - provides a slight bit of rigidity, not a lot). If the document contains unstable inks, I use a sheet of glassine to cover the top of the document - this will prevent any migration of the inks to the mylar surface caused by static electricity. This is somewhat opaque though, so viewing while still possible, is somewhat obscured.

The sleeved documents are placed into a archival storage boxes that include an internalized layer of carbon/zeolyte which assists in absorbing gaseous pollutants that cause accelerated degradation on cellulosic materials.

This probably goes without saying, but one should minimize skin contact with documents, using cotton gloves to handle them and always providing mechanical support to prevent bending, creasing, etc., whenever possible. Minimize contact with direct light, especially strong UV sources like the sun. If one has control over temp. and humidity - cooler temps. are best with RH in the 40-50% range.

Hope any of this is useful!