CHINESE LACQUER – SHORT OVERVIEW OF TRADITIONAL TECHNIQUES AND MATERIAL CHARACTERISATION FOR CONSERVATION PURPOSES

Abstract

Chinese lacquer (urushi) is an ancient natural finishing material obtained from the sap of the lacquer trees (Rhus vernicifera). This has been used for millennia to protect and decorate furniture and various artefacts made of wood or other materials. Lacquered objects are important components of Chinese and world cultural heritage and their conservation imposes a good knowledge and understanding of the material and traditional techniques. This paper presents basic information on the Chinese lacquer as material and lacquering techniques in their historic evolution during different dynasties. The experimental part looked at the physical properties of raw urushi lacquer, respectively aspect, solids content and miscibility with different solvents. A limited compatibility with white spirit as potential thinner was demonstrated. Furthermore, the microstructure of the cured film and characteristic chemical features of raw urushi lacquer as liquid and cured film were investigated. The cured film of raw urushi presents a characteristic microstructural pattern. FTIR spectroscopy revealed a partial oxidation and polymerization following processing by Kuromisation. The further curing accentuated these changes, visible as a decrease of hydroxyl absorptions bands (3400 and 1360cm-1 ) occurring in parallel with an increase of carbonyl band (1740cm-1 ). A strong decrease of the absorption band at 1270cm-1 , which nearly disappears for the cured film, was also observed

Keywords

• chinese lacquer
• raw urushi
• Kurome urushi
• miscibility
• microscopy
• FTIR