Shellac for Water-Proof Coatings, Dyes, Paints, and Printing-Inks.

Manufacturer and builder 5, 1869

A solution of shellac in ammonia, after having become to a certain extent concentrated from exposure to the air, possesses, according to Puncher, very remarkable properties. They are of such a nature as to warrant the belief that the use of ammoniacal solutions of shellac will soon prevail extensively in the arts. The solution is prepared by putting three parts of white shellac, one part of sal-ammoniac, and from six to eight parts of water in a bottle, and then allowing the bottle to stand well corked for twelve hours. Thereafter the contents must be boiled until dissolved. During the process of boiling a constant stirring must be kept up. The solution as thus ob-tained may take the place of the alcoholic shellac solution used by hatters, or, if diluted with twelve parts of water and mixed with terra de siena and ochre, it may be used as a paint for floors. If to an ammoniacal solution of shellac a dilute solution of Cassel brown in sal-ammonic be added, a durable water-proof, brown dye for wood is obtained. By previously digesting the sal-ammoniac solution with logwood or Brazil-wood, various shades of brown in combination with the Cassel brown may be produced. Mixed half and half with Runge's ink, or ground with soot, an ammoniacal solution of shellac forms a preparation for coating leather or wood, or for addressing boxed goods. Such a coating is perfectly water-proof. By grinding it with carefully prepared chalk, it may be used in the manufacture of pergament-paper, or ground with colors it becomes an element in the manufacture of water-proof wall-paper. But for this pur-pose colors that have been adulterated with gypsum, as, for instance, some carmine lakes, inferior chrome-yellows, or green of Neuwied, should be rejected, from the fact that they decompose the shellac solution. The most interesting and useful property of this solution consists in its solvent action upon some of the aniline dyes. Aniline green, which is soluble only in acidulated spirits of wine, is readily taken up by a hot shellac solution that contains eight parts of water to one part of the original preparation. Aniline yellow is readily taken up by means of boiling water, but in such cases only a pale shade of color is produced upon non-nitrogenous substances, such as paper and wood. If a shellac preparation of the proper degree of concentration is added to a solution of yellow aniline dye in water, dyes are obtained which are water-proof, and applicable to both wood and paper. Different shades of color may be given to this yellow dye by means of the above-mentioned solution of green aniline, or a most beautiful red ink or dye for wood may be obtained by adding a solution of carmine in ammonia to it. If a solution of Magenta red in water is boiled for some time with the original shellac solution, it is first converted into violet, and then into blue. This process takes place with the separation of an insoluble blue color, and the blue solution obtained may be used in the manufacture of inks, wood-dyes, and for coloring paper pulp. Again, by thoroughly mixing small quantities of common salt, gypsum, or dilute acids with these colored inks, dyes of great vivacity and body separate, which when leached with water may be employed for marbling paper, or as print colors for wall-paper and fabrics of various kinds. It may be used alone, or mixed with starch paste. When ground with linseed-oil and printer's varnish, they may be used for book, stone, and calico printing. If they are mixed with more sulphate of lead or gypsum, they give rise to a series of bright-colored paints. If, instead of the ordinary shellac, that of the best quality is employed, the solution is particularly serviceable as a binding material for water-colors. Pictures painted with such a color possess not only more freshness and greater durability, but are also water-proof, like oil-paintings. It is quite certain that these ammoniacal solutions of shellac will find application in the decorative art instead of glue; and finally, as a hint to painters, it may be remarked that they form an excellent drying material when used in combination with white-lead and zinc-white.

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