US2419851A - Stabilized colored smoke composition - Google Patents

Description

Patented Apr. 29, 1947 STABILIZED COLORED SMOKE COMPOSITION John W. Orelup, Short Hills, N. J.

No Drawing. Application March 24, 1944, Serial No. 527,957

3 Claims. 1

The present invention relates to improvements in the production of colored smokes used for the purpose of signals, military pyrotechnics, and daylight fireworks.

Compositions for the production of colored smokes comprise mixtures of organic dyestuffs with compositions evolving heat. After ignition of the mixture, the vapors of the heated dyestufi are automatically forced through small orifices in the canister in which the compound is packed. These vapors then condense by contact with air producing a smoke.

The compositions favored at this time for the heat source are mixtures of lactose and potassium chlorate and the proportions must be varied depending upon the dyestufi used. Other readily ignitable mixtures, capable of supporting combustion and suitable for use in signal bombs or the like, may of course be used as the heat source.

In the course of tests involving hundreds of dyes, it was found that very few dyes had the required stability and correct volatility to produce a good smoke of fixed color. A comparison of the amount of dyestufi used and the amount converted into smoke showed very large losses of material destroyed by combustion. Furthermore it was observed that certain dyestuffs accelerated the combustion and that others retarded it. No variation of lactose and chlorate, or changing size or position or orifices was found to prevent some dyes from flaming or showing a white smoke either at once or later during the burning of the signal.

It is a primary object of the present invention to improve combustion for the production of colored smokes by the inclusion therein of an agent for modifying or controlling the combustion so as to prevent or reduce the destruction of the dyestufi and to result in its vaporization or burning in such a manner as to yield the greatest amount of smoke of the desired color. In general the agents found successful appear to act as stabilizers preventing the dyestuff from breaking down so that it flames or produces only a white smoke. With the use of such agents it is possible to preserve in the smokes the color properties of many dyes which would otherwise be unusable for the production of colored smokes, and also to improve the action of the more stable dyes and make them more efiective and longer burning.

I have discovered that the substances most effective for accomplishing the above object comprise urea and its alkyl derivatives, particularly the methyl, ethyl, propyl, butyl, and higher alkyl derivatives. Up to this time I have found urea itself the most desirable for use. Dyes which give only a white smoke or flame without urea give good colored smokes when urea is used. Depending upon the type of dyestuff, from 5% to 20%, more or less, of the whole mixture including the dye and heat producing compound should be urea. If too much urea is used the signal is slow to ignite, if too little, the signal either burns as a white smoke or flames. By using urea with dyestufis which have been found reasonably satisfactory for the production of colored smokes without the urea addition, an improvement is shown especially in the larger sizes of canisters where there is a great loss of materials by combustion. The yield of smoke is greater and if desired, the weight of the signal can be reduced. This is a considerable advantage in parachute types of signals and for any application where smaller size and weight is important. In rocket mixtures the urea can be used to govcm the rate of burning and also as a source of gas.

Examples of smoke signal compositions illustrative of the invention are as follows, it being understood that the invention is in no way limited thereto:

The dyestufis used in the following examples are intimately mixed with urea in the following proportions:

For yellow signal:

Percent Quinophthalone 90 Urea 10 For blue signal:

1.4 Di (amyl amido) anthrachinon 85 Urea 15 For green signal:

1.4 Di (amyl amido) anthrachinon 51 Quinophthalone 34 Urea 15 Red No. 1:

2 methoxy benzene azo 2 hydroxy naphthalene 85 Urea 15 Red No. 2:

2-naphthalene-azo 21-hydroxy naphthalene Urea 20 Orange:

2-chlor benzene azo 2-hydroxy naphthalene 75.5 2 methoxy benzene azo 2 hydroxy naphthalene Urea 15 These color bases are mixed 5 parts by weight with 3 parts potassium chlorate and 2 parts lactose. The materials are finely powdered and mixed carefully, then rammed or pressed into containers leaving a central canal and other channels to allow the colored vapors to escape on ignition.

The above proportions are suitable for small signals of the size of 10 gauge shotgun shells. These proportions may require some variation and adjustment if larger sizes of signals are prepared.

In some instances the density and coherence of the smoke signal produced by the combustion of the above or other colored smoke producing mixtures may be improved by the addition of a volatile vehicle for carrying the dye, which vehicle is preferably of a waxy, fatty or oily nature such as stearic acid, white mineral oil, or petrolatum. Such vehicles may be added in quantities up to about 10% of the whole mixture.

I claim:

1. A composition for the production of colored smokes for signals and the like, comprising a mixture of an organic dyestuff, an ignitable heat producing compound which may be incorporated with the dyestufi" in such composition, and when ignited will be consumed and volatilize the dyestuff so as to produce a colored smoke, and urea for stabilizing the combustion.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,448,073 Lucas Mar. 13, 1923 2,173,756 Kronenberg Sept. 19, 1939 2,030,096 Brooks Feb. 11, 1936 FOREIGN PATENTS Number Country Date 128,986 British July 10, 1919 591,113 French Apr. 1, 1925