Lac wax

Description

A solid fatty acid ester compound obtained from Shellac resin. Shellac contains approximately 3-6% wax and is separated as a byproduct during shellac processing. Lac wax primarily contains myricyl and ceryl alcohols with a small proportion of heavier alcohols and some hydrocarbons ranging from C42 to C68. As early as the 17th century lac wac was imported to Europe and used as a sealing wax. The hard, golden-color wax is no longer commonly used. In shellac varnishes, the incomplete removeal of lac wax can produce a hazy appearance.

Synonyms and Related Terms

cera de laca (Esp.); shellac wax; lacwax

Risks

• Combustible.

Physical and Chemical Properties

• Iodine value=6.0-8.8
• Acid value=12.1-24.3
• Saponification value = 63.8-83.0
• Melting Point = 78-82 C
• Density = 0.971-0.980 g/ml

Resources and Citations

• R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966

• Thomas Gregory, The Condensed Chemical Dictionary, Reinhold Publishing, New York, 3rd ed., 1942

• John S. Mills, Raymond White, The Organic Chemistry of Museum Objects, Butterworth Heineman, London, 2nd ed., 1994

• Encyclopedia Britannica, http://www.britannica.com Comment: "lac" [Accessed February 6, 2003]. gives 17th c. for first use in Europe

• CRC Handbook of Chemistry and Physics, Robert Weast (ed.), CRC Press, Boca Raton, Florida, v. 61, 1980 Comment: melting point = 79-82; density=0.971-0.980; iodine value=6.0-8.8, acid value=12.1-24.3; saponification value = 63.8-83.0