Tags

, ,

Object: 18th century (?) silk lace and cotton ruffs (ruffles), part of men’s coat. The upper part is made of white cotton and is slightly gathered,  while the lower part is made of silk lace. Hand-stitched using cotton thread.

Condition: small tears in the lace, deformation due to wear, overall grey appearance, the dirt was embedded in the fabric.

The object had to be wet-cleaned twice, the first cleaning was not effective.

To clean I used two types of surfactant Berol (AkzoNobel) that were available at the studio where I was based at the time.

1st wet cleaning: Amphoteric surfactant Berol 784.  Amphoteric surfactants contain both cationic and anionic groups. Their main characteristic is their dependance on the pH of the solution (Tadros T. F. 2005. Applied Surfactants: Principles and Applications). In acid solution the molecule acquires a positive charge and behaves as a cationic surfactant, but in alkaline pH solution they become negatively charged and behave like an anionic one. Its properties, foaming, wetting, detergency etc. depend strongly on the solution pH.

Tadros states that (p 7):

‘a specific pH can be defined at which both ionic groups show equal ionization’

N+ … COOH                                      N+ COO-                    NHCOO-

acid pH < 3 (acts as cationic)           isoelectric          pH >6 alkaline (acts as anionic)

Method used: Ruffs were cleaned using the so-called puddle method, this is cleaning with minimal amount of water on the table surface/no immersion. Concentration: 0.5 ml/1 l for the first bath and 1 ml/1 l for the second. Used sponges to clean, each bath lasted 8 min. Deionised water was used to rinse the textile by sponging, no immersion (3 rinses). Dried by blotting (fabric and paper), padded and edges sandwiched between the blotting paper to prevent tide lines. Cold fans were used to assist with drying.

pH was kept between 6 to 7. In theory, the amphoteric surfactant should have been acting as anionic at this pH.

Result: The overall appearance of the textile was slightly grey with dirt still visible on the cotton and also deposited on the blotting paper.

2nd wet cleaning: 

for the 2nd wet-cleaning I used anionic surfactant Berol 480 in concentration of 1ml/  l for the first bath, and 2ml/1l for the second bath. This time I used the full immersion method. Following cleaning, the ruffs were rinsed five times: two immersion rinses and three running rinses. pH : 6 during washing, restoring to 7 after rinsing.

Result: overall, a significant visual improvement, no shrinkage, no redeposition of dirt on the blotting paper.

Discussion: the problem with the 1st cleaning was not the amphoteric surfactant but the puddle method. puddle method is a good way to wet-clean very fragile textiles that can’t be subjected to agitation in the bath. One way to improve this method is to increase the volume of water used to wash and rinse the textile in situ (on the table surface), the water should be quickly replaced by blotting the excess away, to remove the washing solution loaded with dirt. i have since used this method successfully to clean a very fragile silk embroidery on white linen background.

one more post on wet-cleaning of historic textiles

© Luba Dovgan Nurse and luba’s conservation, 2000-2014.

selected references:

Tinkham, R. 2001. Soil Removal and Redeposition on Cotton, Nylon, and Poiyester Fabrics Wet- Cleaned with Anionic and Nonionic Surfactants, thesis submitted towards MS in Conservation, University of Alberta.

Lewis J & D. Eastop 2001. Mixtures of anionic and non‐ionic surfactants for wet‐cleaning historic textiles: A preliminary evaluation with standard soiled wool and cotton test fabrics, The Conservator, 25 (1).

Lewis, J. (1 996). Evaluating mixtures of anionic and non-ionic surfactants for wet-cleaning historic textiles. Postgraduate Diploma in Textile Conservation. The Textile Conservation Centre: Hampton Court Palace.

Tadros T. F. 2005. Applied Surfactants: Principles and Applications.

Advertisements