A polymer coating was applied to 20 Japanese sugito (cedar doors) in the Philadelphia Museum of Art (PMA) during the 1960s to protect and consolidate their elaborate painted decorations.The pair shown below, titled Queen Mother of the West, measure 161.9 × 219.7 cm. The polymer used is referred to as soluble nylon in the art conservation literature; one product was sold by Imperial Chemical Industries, Ltd.(ICI) under the tradename Calaton CB. Although soluble nylon was favored for its flexibility, clarity and adhesive properties, it is no longer used as it ages poorly and becomes insoluble. Coating and paint samples from the doors were studied by FTIR, Raman and other techniques. Calaton CB is a derivative of nylon 6,6. Partial N-methoxymethylation of nylon 6,6 results in a polymer soluble in methanol in contrast with the highly insoluble nylon 6,6. Calaton CB samples were obtained from the Winterthur Museum, Getty Conservation Institute, and other sources. Calaton CB cast films also are being investigated and compared with both commercial nylon 6,6 and the sugito samples. The four infrared spectra shown below illustrate both major similarities and minor (but significant) spectral differences between nylon 6,6; Calaton CB powder; Calaton CB cast film; and the soluble nylon on the sugito. There is little change between the powder and cast film (to date); aging studies are in progress. The spectral changes observed in the sugito samples may be influenced by the underlying binder and/or pigments, but the spectral similarity to nylon 6,6 is clear. This investigation also is of significance internationally as comparable sugito in Nagoya and Nijo Castles, Japan are national treasures and therefore their decorations cannot be sampled.

Investigation of a soluble nylon applied to Japanese sugito

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.