Volume 9, Number 3
May 1985

Pyroxylin vs. Aqueous (Acrylic) Coated Cloth

Even though "aqueous" coated cloth has been commercially available as an alternative to pyroxylin for two or three years, no systematic comparison of their qualities has appeared in print. The "aqueous" coating has a large component of acrylic in it, and acrylics have a good reputation among conservators because they are so stable; pyroxylin, on the other hand, is made of cellulose nitrate, which has a bad reputation because some forms of it are flammable and chemically unstable. Still, we do not want to judge a dish by the recipe. Pyroxylin has been a pretty good cloth coating for several decades, and no one has showed us yet that the aqueous cloth is better.

We need to know how the two coatings compare with regard to how well they retain their important qualities as they age--flexibility, pH, flammability, color, strength, and so on. The subvention review panel of the National Historical Publications and Records Commission plans to look into this matter later this year.

In the absence of research results on these two coatings, a simple test was performed in the Preservation Department at Brigham Young University by Kirby Packham, head of the Book Repair Unit. He took a sample of each kind of buckram and burned then. His observations: "Both ignited and burned about equally readily, but the aqueous coated buckram was harder to put out. I had to put water on it to stop it from smoldering. Both smoked and smelled while burning. The cloth on the pyroxylin sample seemed to burn faster than the coating but with the aqueous sample the coating seemed to burn faster.

Joanna Western Mills Company (220 Broad Street, Kingsport IN 37660, 615/247-2131) is the only cloth manufacturer in this country with a standard aqueous coated product on the market in colors and weights to replace pyroxylin. However, in January Joanna decided not to sell "retail" amounts of its aqueous buckram (under 2500 yards at a time). Smaller amounts cannot even be obtained through Gane Brothers and Lane. However, this limitation may not apply to the cloth Grades A-C, or to the imitation leather, Lacqroid, from Joanna.