US 2546791 A
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Patented Mar. 27,1951 7 MASKING THE ODflR OF AMMONIA IN DEVELOPING DIAZOTYPES Sam Charles Slifkin, Binghamton, and John Sulich, Jr., Endicott, N. Y., .assignors to General Aniline & Film Corporation, New York,- N. Y., a corporation of Delaware No Drawing. Application December 16, 1948, Serial No. 65,729
This invention relates to a process for masking the odor of ammonia and to the resulting composition.
Aqueous solutions of ammonia are employed for many purposes which require the volatilization of the dissolved ammonia from the solution. The volatilized ammonia can be confined within a given space only by means of gas tight seams and connections in the apparatus used. It is often impractical to do this and in such cases the ammonia gas will escape into the surrounding atmosphere creating an intolerable situation because of the characteristicly unpleasant pungent odor of the ammonia.
A particular case where this problem is of considerable concern is the process of dry developing diazotype light sensitive material. Exposed dry developable diazotype materials are usually developed by drawing them across the perforated surface of a tank in which ammonia is being vaporized by means of an endless belt travelling around rollers on either side of the perforated surface. Since the diazotype material to be developed must have ready entrance to and exit from the developing surface, it is difiicult to seal off the escape of the ammonia. Furthermore, the diazotype material itself will absorb and carry out a certain amount of occluded gas.
In order to counteract the offensive odor of the ammonia vapors emitted to the atmosphere in the i above described diazotype developing process and similar processes, it is proposed by this invention to add an ingredient to the aqueous ammonia solution which will mask the odor of the ammonia .volatilized therefrom. The ingredient which is added is an aromatic volatile material which will volatilize with the ammonia. It should be readily dispersible, but not hydrolizable in aqueous ammonia solution; It should be sufficiently volatile to remain vaporized with the ammonia and not condense upon the cooler portions of the equipment with which it is used so that smearing of the prints during development may be avoided. It should not have a sweet or objectionable odor but a pleasant odor sufficiently strong to mask the odor of the ammonia. In the process of developing diazotype reproductions by the ammonia or dry method a small concentrationjof the volatile ingredient should be left on the diazotype print by occlusion of the vapor in the pores of the diazotype support material such as paper. Thus a residual pleasant odor will be maintained on the diazotype prints overriding the characteristic ammonia odor which would otherwise predominate.
We have found that a solution in isopropyl alcohol of an essential oil such as petitgrain oil which, preferably, is free of terpenes has the properties necessary to perform the ammonia odor masking function. Such a solution of petitgrain oil is readily dissolved or dispersed in aqueous solutions of ammonia. The petitgrain oil does not hydrolize in the aqueous ammonia. It vaporizes with the ammonia upon application of heat or release of pressure in an evaporating chamber and its pleasant odor dominates and obscures the characteristic unpleasant odor of the ammonia. It does not condense out of the vapor mixture upon contact with cool portions of the equipment in which it is being evaporated such as a diazotype ammonia developer. The petitgrain oil also has the same property as ammonia of becoming occluded, in the vapor stage, to the surface of paper or other like medium used as a support for diazotypes. It accordingly imparts a residual pleasant odor to ammonia developed diazotype prints which obscures any residual odor attributable to the ammonia.
As an example of a suitable concentration of the volatile aromatic oil for masking the odor of ammonia we suggest the addition of 30 cc. of a 10% solution of petitgrain oil free of terpenes in isopropyl alcohol to one gallon of aqueous ammonia (28% NH4OH). That is approximately one part of the 10% petitgrain oil/isopropyl alcohol solution in 126 parts by volume of the 28% aqueous ammonia solution. Coloring matter such as a spirit soluble aniline dye of high tinctorial strength may be added for identification purposes.
The solution of the petitgrain oil or other essential oil may be prepared and stored or distributed in a form ready for use in the aqueous ammonia by dissolving the essential oil in the solvent, such as isopropyl alcohol to the desired strength. A 10% solution of the essential oil in the solvent is generally adequate. If desired a small amount of the spirit soluble aniline dye may also be added in order to give the essential oil solution a distinctive color facilitating its identification.
What we claim is:
1. The process of developing diazotypes by means of odor masked ammonia vapors which comprises contacting the diazotype material with the vapors from an aqueous ammonia solution of petitgrain oil dissolved in isopropyl alcohol.
2. The process of developing diazotypes by means of odor masked ammonia vapors which 2,546,791 r 'o s;
Comprises oontacting the diazotype material with the vapors from an aqueous ammonia solution of petitgrain oil, free of turpines, dissolved in isopropyl alcohol.
SAM CHARLES SLIFKIN. JOHN SULICI-I, JR.
REFERENCES CITED Name Date Ellis May 1, ,1926
Number 4 OTHER REFERENCES Druggists Circular Formula Book, 2d ed. (1920 pp. 95, 96, 9'7.
Hiss and Ebert: New Standard Formulary, 5th 5 .ed. 1920). pp. 927, 92s.
Poucher: Perfumes, Cosmetics, and Soaps, vol. 2, 3d ed. (1929), pp. 460 to 463.
.Poucher: Perfumes, Cosmetics, and Soaps, vol. in 1, 5th ed. (1942), pp. 334, 335.