Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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mangrove (bark)

Trees of the family Rhizophoraceae, especially those of the genera Rhizophora, Bruguiera, Aicennia and Ceriops, the barks of which are rich in tannin. The tannin content of mangrove barks varies widely, however, from less than 10% to more than 40%, depending upon a number of factors, including the species, as well as the age, exposure to sun and air, location on the tree where the bark is removed, etc.

As a tanning material mangrove bark has both advantages and disadvantages. Its principal disadvantage is the reddish color it imparts to leather (See also: HEMLOCK ), although this can readily be overcome by mixing mangrove with other tanning materials which modify or reduce the intensity of the color. The leather produced by the use of mangrove alone also tends to be harsh and thick-grained. When used with other tannins, however, as it usually is, mangrove provides a very satisfactory tannage. The rate of penetration of the tannin is slower than with such tannins as wattle or quebracho, but can be increased by sulfiting.

Mangrove is considered to be the most economical and abundant vegetable tannin available today. It is one of the condensed class of tannins, has a fairly high pH and a relatively low acids content. It is very soluble and develops a minimum of insoluble matter. It also produces very little sludge in the tanning liquor.

Mangrove is inaccurately (but persistently) referred to as "cutch" or "kutch." See also: VEGETABLE TANNINS . (175 , 306 , 363 )




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