Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

 Previous item  Up One Level Next item

shellac

A resinous secretion of the insect, Tachardia lacca, which breeds on the twigs of certain Indian trees. It was originally used as a source of dyestuff, but is now used almost entirely for its content of resinous matter. Shellac has a softening temperature of 60 to 75° C., but decomposes if heated much above 100° C. It is soluble in alcohol, except for about 4% wax, which is insoluble in cold alcohol. It represents the most highly refined form of LAC and is prepared in the form of thin orange or yellow flakes. The term is also used with reference to the varnish prepared by dissolving shellac in alcohol. Shellac is used in the manufacture of leather, in lithography, in the preparation of finishing sizes, etc. See a1so: SHELLAC SIZE . (233 , 235 )




[Search all CoOL documents]


URL: http://cool.conservation-us.org/don/dt/dt3082.html
Timestamp: Saturday, 19-Nov-2011 13:18:44 PST
Retrieved: Thursday, 23-Nov-2017 07:19:23 GMT