Coal-Tar Colours in the Decorative Industries (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922. Excerpt: ... CHAPTER II MORDANTS Metallic Salts--Tannin Bodies--Oils. The term Mordant, which has been used fairly frequently in the preceding chapter, refers to a class of bodies of immense importance in the application of dyestuffs. A mordant may be taken as being a body which is used to combine with, precipitate, or fix a soluble dyestuff on textile materials or inert substrata. For example, tannic acid is an ideal mordant for basic dyestuffs, since it forms with these colours insoluble tannates, and the insoluble tannates can be produced very conveniently upon textile materials and inert substrata by successive treatment with tannic acid and dyestuff. Metallic oxides and salts are very largely used as mordants for the production of alizarine and other colours. The chief mordants in use are as follows: --Metallic Salts. Aluminium.--Alum, aluminium sulphate and basic aluminium sulphate, aluminium acetate, sulphate-acetate, thiocyanate, nitrate, chloride, tartrate, oxalate, thiosulphate, etc., and aluminate of soda. Chromium.--Potassium dichromate, sodium dichromate, chromates of lead, barium and copper, chrome alum, chromium sulphate, sulphate-acetate, nitrate, chloride, thiocyanate, nitrate-acetate, etc. Iron.--Ferrous sulphate, acetate, chloride, nitrate, thiosulphate, ferric sulphate, nitrate, acetate, chloride, iron alum, etc. Tin.--Stannous chloride, nitrate, stannic chloride and stannate of soda. The above salts are used in both cotton and wool dyeing, in calico printing, lake-making and in any case in which is required the production of an insoluble shade from alizarine, certain acid, etc., dyes. Salts of lead, manganese and copper are also used as mordants for special purposes. Tannin Mordants. Tannic acid and tannin materials such as sumach, gall-nuts, divi-..