Dyeing and Printing Aniline Colors.

Scientific American 7, 17.8.1861

A most important patent has recently been taken out in England by R. H. Gratrix[?], of Salford, and M. P. Javal, of Thann, France, for preparing and applying aniline colors to textile fabrics. The specification of the patent is published in Newton's London Journal. It relates that hitherto, in the use of this class of colors for producing patterns upon textile materials and fabrics, the mode adopted for fixing them has been to use albumen, lacterine or other azotized substances; but either from the cost of these materials, or the loose and fugitive character of the applied colors, no cheap and fast goods could be produced.

In order to obtain patterns by the aid of printing in the above-named class of colors, which patterns shall be chemically fixed, the patentees precipitate the color on the fabric in the following manner: they first form a compound of tannin with the color which is desired to be employed, and thicken it with gum senegal or other suitable thickening material; they then take the article to be operated upon, say forexample, the cloth known in the trade as "prepared cloth" - that is, cloth on which tin or other suitable metallic base has been precipitated by any of the wellknown preparation processes - and impress upon this cloth the prepared or combined color, by meand of printing blocks or engraved rollers. Or, as a modification of this improved process, they print upon the prepared cloth the desired pattern with a composition consisting of a thickened solution of gall nuts. By this means there is formed on those parts only of the surface which are to carry the colored pattern, a combination of tannin with oxyd of tin or other suitable base. This fabric is submitted to a bath composed by preference of a dilute acid solution of any desired color, derived from aniline or analogous substances. By either of these processes a precipitate of the color employed is obtained on the fabric, and thus, in a comparatively inexpensive manner, the colored pattern is firmly fixed on the fabric.

In order to form compounds of tannin with the color to be employed, add to a solution of blue, purple or red color, or their combinations, derived from aniline and analagous substances, so much of a strong solution of galls (a newlymade solution being preferred) as is sufficient to precipitate all the coloring matter, or use the pure tannin, if the expense be not objectionable; then collect the precipitate upon a filter, and wash it, and dry it or not, as may be thought desirable. Re-dissolve this precipitate in acetic acid, alcohol, methylated spirits, or other suitable solvent, and thicken it with gum senegal or other suitable thickening, and it is then ready to be used for printing upon cloth prepared with salts of tin or other suitable mordant or mordants. When the fabric has been printed, it is to be steamed and then washed, with or without the use of soap, according to the color under operation; the red color more particularly requiring such treatment with soap.

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