Improved Compound of Aniline Colors.

Scientific American 18, 2.5.1868

Emil Zinssmann, of New York city, has lately patented the following:
"This invention consists in a compound, which is soluble in water, and made of aniline colors, which, in themselves, are not soluble in water, by treating said colors with glue or gelatinous materials, or with different kinds of gums, such as gum arable or gum tragacanth, or with starch, which is soluble in water, or with other equivalent materials, either alone or mixed together, in combination with either acetic acid, or glycerin, or eaccharine solutions or decoctions of plants, or any other liquid which will produce the desired effect; said materials being combined mechanically to a thick siruplike homogeneous mass, and then mixed together with the anilihe color (which is to be rendered soluble in water), and, heated in such a manner that a product is obtained which retains all the coloring properties and qualities inherent to the aniline colors, and which is so perfectly soluble in water that it can be used with the best success for dyeing and printing all fibrous materials, and consequently the expensive operation of dissolving the aniline colors in alcohol, which, with aniline colors as now made, is indispensable, particularly for dyeing and printing wool or cotton, or fabrics made therefrom, can be dispensed with.

"In carrying out my invention, I proceed, for instance, as follows: I take a quantity of glue (about from two to six pounds of glue to one pound of the color), and dissolve the same in common acetic acid of seven or eight degrees, so as to form a thick, siruplike mites. With this thick solution I mix the aniline color previously reduced to a fine powder, and then I work the mass until it forms a fine thick homogeneous pulp, either by means of suitable stones, or by passing the mass through a mill, or in any suitable manner. The pulp thus obtained is then placed into a suitable vessel (best an enamelled kettle), and heated in a water bath under constant agitation or kneading, it being desirable at the same time to provide the vessel containing the pulp with a tightlyclosing cover, so as to prevent the undue evaporation of the liquid parts of the mass. It must be remarked, however, that the desired reaction, or, in other words, the perfect dissolution of the aniline color in the glue, or the, equivalent material, will take place only and best when the pulp in the water bath forms a mass of such thickness and consistency that it just can be kneaded or stirred. If the pulp should, however, become so thick that it cannot be stirred or kneaded before the aniline color is perfectly dissolved in the glue or equivalent material, the addition of a small quantity of the corresponding liquid is sufficient to reduce the pulp to the desired consistency. From time to time a small quantity of the pulp is taken out, dissolved in hot water, and while hot passed through a filter, and if no color remains on the filter, the process can be considered completed, and the product can be used immediately, or it can be dried and preserved for future use.

"For purple aniline colors, with the exception of the bluish purple, such as "Parme," or of the aniline blue, about two or three pounds of glue or gelatine to one pound of the color are sufficient, but for bluish aniline, such as "Parme," or for aniline blue, it is better to use from four to six pounds of glue or gelatine. For blue aniline, or for "Parme," the use of glue and acetic acid is to be recommended, but for purple aniline I can use gums, or starch which is soluble in water (dextrine), and the acetic acid can be replaced by glycerin or decoctions of plants, such as soapwort (Radix saponica), or materials of a similar effect, and this change is to be recommended, because the acetic acid affects and injures the hue of the purple aniline colors. If glycerin and glue are employed, it is necessary to soften the glue first in a small quantity of water, and then to effect the combination of the glycerin and glue by heating them together.

"By this treatment I am enabled to produce from aniline colors, which in themselves are not soluble in water, a compound which is perfectly soluble in hot water, thus forming a solution which is applicable with great advantage in place of the expensive and unreliable alcoholic solution of mid colors. The great saving effected thereby is apparent from the fact that at present, for the purpose of dissolving one pound of purple or blue aniline colors (particularly for the purpose of dyeing or printing woolen and cotton materials), from twenty to thirty pounds of the strongest alcohol, or a still larger quantiy of methylene or wood spirit, are required, and even then the solution thus produced is not reliable or perfect. If the alcoholic solution remains standing a short time, a portion of the color is precipitated from the same, and if said solution is used for dyeing, the color of the dyed fabric is many times not uniform, and liable to come off. By the use of my compound all these disadvantages are avoided, it dissolves perfectly; the coloring matter is not liable to precipitate from the solution, however long said solution may remain standing, and wool, silk, cotton, also paper, and different other materials or fabrics can be dyed or printed therewith with the greatest ease and perfection.

"I am well aware that products soluble in water have been prepared by treating aniline colors with sulphuric acid, but such products are applicable more particularly for dyeing and printing leather or silk, but little or not at all for dyeing and printing of wool or cotton or fabrics made therefrom. I am also aware that some time ago, glycerin or decoctions of plants have been recommended for the purpose of dissolving aniline colors. But the extensive and common use of alcohol as a solvent of these colors, shows that said materials did not produce the desired result. I have never succeeded in producing, with these lastnamed materials alone, anything like a satisfactory result, and it is only possible to effect the solution, if at the same time a substance is used, such as glue, or equivalent material, as above specified.

"Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is: A compound, which is soluble in water, and made from such aniline colors which in themselves are not soluble in water, by treating said colors with glue or equivalent substances, either alone or mixed together, and with a liquid, such as acetic acid, or glycerin, or their equivalents, either alone or mixed together, as herein set forth."