US3335040A - Pyrotechnic disseminating composition containing a nitramine fuel - Google Patents

Description

United States Patent Ofiice 3,335,040 PYROTECHNIC DISSEMINATING COMPOSITION CONTAINING A NITRAMINE FUEL Earl Thomas Niles, Midland, Mich., assignor to The Dow Chemical Company, lVIidland, Mich., a corporation of Delaware No Drawing. Filed Nov. 21, 1966, Ser. No. 595,576 5 Claims. (Cl. 149-76) ABSTRACT OF THE DISCLOSURE The invention is a novel pyrotechnic disseminating composition employing nitramines as fuel, inorganic oxidizers which readily are combustible at atmospheric pressures as oxidizer and effective quantities of an agent to be disseminated.

This invention relates to pyrotechnic dissemination and more particularly is concerned with disseminating systems based on novel pyrotechnic fuel formulations employing nitramines as fuel.

Pyrotechnic disseminating formulations are widely employed for colored smoke production used as a signal or screen, for the distribution of plant growth regulating agents such as pesticides, fumigants, herbicides and the like and for the release and distribution of chemicals used in Warfare and law enforcement such as tear gas, psychotomimetic incapacitating agents and the like.

The primary problem in disseminating such signalling and treating materials, hereinafter referred to as agents, by pyrotechnic means is in providing a combustible mixture evolving large quantities of gaseous combustion products which burns at a sufliciently low temperature such that the agent being disseminated is not detrimentally degraded or destroyed. In general, such compositions should provide large volumes of gaseous combustion products while undergoing complete burning at a low burning pressure, e.g. a maximum of about two atmospheres, and a maximum buring temperature of about 800 C. and preferably from about 300 to about 600 C. It is another criterium of operation that the agent to be disseminated must be compatible with the pyrotechnic composition to assure reliability of burning after storage as well as storageability without mix degradation.

Heretofore, pyrotechnic dissemination of smoke dyes, herbicides, chemical warfare materials, tear gas and other like agents has been carried out using compositions wherein substantial amounts of the agent to be disseminated are mixed with cool burning fuel-oxidizer combinations which provide copious quantities of water vapor and carbon dioxide as the principal gaseous exhaust products. In these formulations, many times undesirable high percentages of the agent are lost through degradation during the combustion dissemination process.

Empirically, it has been found that a mixture of carbohydrates or sulfur with potassium chlorate in the presence of minor amounts of certain additives, e.g. sodium bicarbonate with sulfur or kaolin with sugar, can be used as a pyrotechnic system for dissemination of colored smoke and chemical warfare agents. These systems can be classified as cool-burning only because of the flame quenching additives employed therein. Polyvinyl acetate in dilute solutions has been used with these conventional pyrotechnic compositions to increase their physical strength and ease of consolidation. Such solutions reduce the amount of pressure needed to compact the formulations into a grain. This is of interest especially with those formulations containing sulfur as compaction of such formulations at high pressure is hazardous in that these 3,335,040- Patented Aug. 8, 1967 compositions during fabrication are prone to ignition. Even when partially compacted, the resulting deflagration borders on detonation with respect to velocity. Oil, as a diluent, has been used to moisten and reduce friction sensitivity in such mixtures. This material, however, undesirably degrades the composition from the standpoint of efliciency of dissemination.

Dissemination of agents of the type set forth herein also has been realized using pyrochemical gas producers as the high volume gas source. To illustrate, self-sustained gas producing reactions as realized by the relatively low temperature catalytic decomposition of ammonium nitrate, guanidine nitrate and nitrogu-anidine utilizing chromates and dichromates as catalysts have been used to disperse benzene hexachloride, DDT and other pesticides. These formulations suffer from the disadvantage that they exhibit relatively low efficiency of dissemination and are not universally applicable.

It is a principal object of the present invention to provide a novel pyrotechnic composition for dissemination of smoke dyes, pesticides, chemical warfare and the like agents.

It is also an object of the present invention to provide a pyrotechnic formulation which is safe to handle during mixing and other production operations when in admixture with an agent to be disseminated.

It is a further object of the present invention to provide a pyrotechnic formulation containing an agent to be disseminated wherein the resultant composition remains stable under prolonged storage even at relatively elevated temperatures of 60 C. or more and which gives high efficiencies of gaseous combustion production and agent dissemination upon use.

It is another object of the present invention to provide a pyrotechnic composition suitable for use with a wide variety of agents ordinarily dispersed by pyrotechnic dissemination.

It is also an object of the present invention to provide a cool-burning pyrotechnic composition for dissemination of agents which requires no coolant additives.

These and other objects and advantages readily will become apparent from the detailed description of the invention presented hereinafter.

The present invention comprises a pyrotechnic disseminating composition employing nitramines as fuel, inorganic oxidizers which readily are combustible at atmospheric pressures as oxidizer and effective quantities of an agent to be disseminated.

More particularly, the present invention comprises from about 17 to about 40 weight percent of 3-amino-1- nitroguanidine, ethylenedinitramine or dinitroethyleneurea, from about 7.5 to about 55 weight percent of an alkali metal or ammonium chlorate or perchlorate such as, for example, sodium chlorate (NaClO potassium chlorate (KClO or ammonium perchlorate (NH ClO and balance, agent to be disseminated.

A preferred embodiment of the present invention comprises from about 25 to about 32.5 weight percent of 3- amino-1-nitroguanidine, from about 12 to about 17 weight percent potassium chlorate, and balance agent to be disseminated.

These formulations exhibit a satisfactory burning rate, are cool burning and develop copious quantities of neutral (i.e. substantially non-reactive with agent) gaseous combustion products to provide good agent dissemination. If desired, however, optionally up to about 5 percent by weight or more, ordinarily from about 1 to about 5 weight percent, and preferably about 1 Weight percent of a combustion catalyst, e.g. chromates, copper salts, platinum, rhodium or iridium metals, ferrocene, metal chromites, ferric oxide and the like can be incorporated into the formulation. Alkali metal chromates, e.g. potassium chromate (K CrO and copper halides, e.g. copper chloride, copper chromite and ferric oxide (F6203) have been found to be particularly suitable catalysts. With the catalysts, sustained combustion is realized at stoichiometric or fuel rich fuel-oxidizer proportions. If the catalyst is not employed, the composition usually must be oxidizer rich to obtain sustained combustion. In some instances, this can lead to undesirable agent degradation during the combustion dissemination process. Additionally, the catalyst provides increased burning rates and increased gaseous combustion product yield and efiiciency of agent dissemination.

Agents for dissemination which can be incorporated into the formulation include for example organic dyes such as methylaminoanthraquinone (MAAQ) used for the production of colored smoke, tear gas agents, incapacitating agents which are psychotomimetics, her-bicides, fungicides, pesticides and the like.

By effective quantities of such agents is meant those amounts whereby a predetermined level of treatment or activity is realized as is understood by one skilled in the art of pyrotechnic dissemination.

The formulations can be fabricated into compacts or grains using techniques and procedures commonly em ployed in the art. Blends usually are made by mixing the components, placing the resulting substantially homogeneous mix into a container, compacting the mix in the container and contacting the so-compacted formulation with an ignition system and igniter.

First Fire and a No. 56 Squib igniter was inserted into the can through this opening and placed in contact with the dissemination formulation.

The so-pressed end burning grain was ignited and burning characteristics, including ease of ignition, burning time, combustion temperature and pressure were recorded. Additionally the aerosol yield,

!gent in Aerosol Form X 100 (Aerosol yield Total Weight Composition and . Agent in Aerosol Form X 100 (Emmemy Agent in Composition also were measured.

The results of these studies are summarized in Tables I and II. To aid in the ease of understanding and ready presentation of the results, the operable and optimum com-position ranges are shown in Table I. Table II summarizes the burning characteristics exhibited by the compositions of corresponding number in Table I.

TABLE I Fuel KO 0 l soxidizer, KzCX'O4 Catalyst, MAAQ Agent Comp. Parts by Weight Partsb We ht P No. Parts by Weight y g ms by Weght Component Operable Optimum Operable Optimum Operable Optimum Operable I Optimum Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max.

1a B-amino-l-nitroguanidine. 17 lb 2a D1n1troethyleneurea... 29 2b 0 3 Ethylenedinitramine 28 1 System not optimized.

TABLE IIB URNING CHARACTERISTICS C Tlgilrning qOombusttion Cti mbustion Clfinltitin Axgflifiol Efficiency,

omp. e, sec. empera ure, ressure arac erie Percent Im act S a k No. (range) 0. (range) (range) istics Percent (range) p p r Fnctmn x51 General (range) 9-15 270-500 M-G G 3641 63-74 G 10-11 -400 G G 4041 73-74 G g g g g 30-33 380???) g-G L-G 25 50 G G G G G N G G 26-32 350-500 MG L-G 25-30 52-60 G G g g 8 1 Formulation compatibility after long term (9-12 weeks) storage at about 70 C P=Poor, L=Low, M=Mediu.m, G= Good (based on Poor as minimal acceptable performance for use in agent disseminating).

Internal burning grains are prepared by pressing or compacting the blend around a mandrel of predetermined shape and size.

The present novel pyrotechnic disseminating formulations offer the unexpected advantage of safety during mixing with agents that are somewhat hazardous to handle in the presence of sulfur. Also, they provide unexpectedly high stability during storage as well as higher efliciency of dissemination when compared with formulations based on conventional pyrotechnic systems.

The following example will serve to further illustrate the present invention but is not meant to limit it thereto.

Example.For aerosol evaluation, a number of formulations were prepared by mixing a nitramine fuel and potassium chromate catalyst, incorporating MAAQ smoke the like, as disclosed herein can be utilized in these compositions.

Various modifications can be made in the present invention without departing from the spirit or scope thereof for it is understood that I limit myself only as defined in the appended claims.

I claim:

1. A pyrotechnic disseminating formulation comprising (a) from about 17 to about 40 weight percent of a nitramine as a fuel member,

(b) from about 7.5 to about 55 weight percent of a member selected from the group consisting of alkali metal and ammonium chlorates and perchlorates as oxidizer, and

(c) balance an effective amount of agent selected from the group consisting of organic dyes, chemical warfare agents, incapacitating agents, and plant growth regulants to be disseminated.

2. The composition as defined in claim 1 and including up to about 5 weight percent of a combustion catalyst.

3. The composition as defined in claim 1 wherein the fuel member is selected from the group consisting of 3- amino-l-nitroguanidine, ethylenedinitramine and dinitroethyleneu-rea and said oxidizer is potassium chlorate.

4. The composition as defined in claim 3 and including from about 1 to about 5 weight percent of potassium chromate combustion catalyst.

5. The composition as defined in claim 1 wherein the fuel member is 3-amino-1-nitroguanidine, said fuel member ranging from about 25 to about 32.5 weight percent, the oxidizer is potassium chlorate, said oxidizer ranging from about 12 to about 17 weight percent and including about 1 weight percent potassium chromate catalyst.

References Cited 7 UNITED STATES PATENTS 2,557,814 6/1951 Dinsdale et al 14985 X 2,557,815 6/1951 Wheelwright et al. 149-85 X 2,707,695 5/ 1955 Courtier 14992 X 3,042,580 7/ 1962 Jacobi 149-'61 X CARL D. QUARFORTH, Primary Examiner.

S. J. LECHERT, JR., Assistant Examiner.

Claims (1)

1. A PYROTECHNIC DISSEMINATING FORMULATION COMPRISING (A) FROM ABOUT 17 TO ABOUT 40 WEIGHT PERCENT OF A NITRAMINE AS A FUEL MEMBER, (B) FROM ABOUT 7.5 TO ABOUT 55 WEIGHT PERCENT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL AND AMMONIUM CHLORATES AND PERCHLORATES AS OXIDIZER, AND (C) BALANCE AN EFFECTIVE AMOUNT OF AGENT SELECTED FROM THE GROUP CONSISTING OF ORGANIC DYES, CHEMICAL WARFARE AGENTS, INCAPACITATING AGENTS, AND PLANT GROWTH REGULANTS TO BE DISSEMINATED.