Low toxicity, environmentally friendly red smoke generating composition and method of making the same

Abstract

The present invention is directed to a novel, low-toxicity red smoke generating composition and a method of making the same, comprising at least one red dye, a coolant, an oxidizer, a non-sugar binder, and a non-sulfur particulate fuel that is also a burn-control agent having at least one particle size distribution. Preferably, the red dye comprises an anthracene or anthraquinone-based dye and the fuel comprises a sugar or mixture of sugars.

Claims

1. A low-toxicity red smoke generating composition, comprising: an oxidizer; a particulate non-sulfur fuel having a particle size range of 10 to 100 microns, and wherein said fuel further includes second particles having a particle size range of 300 to 650 microns; at least one anthracene or anthraquinone-based red dye; a coolant; and a non-sugar binder.

2. The composition of claim 1, wherein said oxidizer is potassium chlorate.

3. The composition of claim 1, wherein said fuel is a sugar selected from the group consisting of dextrose, lactose, sucrose, and mixtures thereof.

4. The composition of claim 3, wherein said fuel is sucrose.

5. The composition of claim 1, wherein said fuel comprises a mixture of a first sugar comprising sucrose (10) having a particle size range of 10 to 100 microns, and a second sugar comprising granulated sucrose having a particle size range of 300 to 650 microns.

6. The composition of claim 1, wherein said coolant is selected from the group consisting of sodium bicarbonate, magnesium carbonate, and mixtures thereof.

7. The composition of claim 1, wherein said binder is selected from the group consisting of nitrocellulose, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl ester, polyvinyl ether, and mixtures thereof.

8. The composition of claim 7, wherein said binder is selected form the group consisting of nitrocellulose, polyvinyl alcohol, and mixtures thereof.

9. The composition of claim 1, wherein said red dye is selected from the group consisting of 1-(Methylamino)anthraquinone (solvent red 111); 1-(Cyclohexylamino)anthracene-9,10-dione (solvent red 168); 1-Isopropylamino-9,10-anthraquinone (solvent red 169); 1,5-bis[(3-methylphenyl)amino]anthraquinone (solvent red 207); and mixtures thereof.

10. The composition of claim 9, wherein said red dye is selected from the group consisting of 1-(Cyclohexylamino)anthracene-9,10-dione (solvent red 168); 1-Isopropylamino-9,10-anthraquinone (solvent red 169); and mixtures thereof.

11. The composition of claim 1, wherein said composition comprises said oxidizer in an amount of 18 to 35 wt. %, said fuel in an amount of 20 to 50 wt. %, said red dye in an amount of 27 to 50 wt. %, said coolant in an amount of 8 to 25 wt. %, and said binder in an amount of 1 to 5 wt. %.

12. The composition of claim 1, wherein said oxidizer comprises potassium chlorate in an amount of about 21 wt. %, said red dye comprises 1-Isopropylamino-9,10-anthraquinone (solvent red 169) in an amount of about 35 wt. %, said fuel comprises a mixture of sucrose (10) and granulated sucrose, said fuel in amount of about 28 wt. %, said coolant comprises magnesium carbonate in an amount of about 16 wt. %, and said binder comprises polyvinyl alcohol or nitrocellulose in an amount of about 2 wt. %.

13. The composition of claim 1, wherein said oxidizer comprises potassium chlorate in an amount of about 21 wt. %, said red dye comprises 1-(Cyclohexylamino) anthracene-9,10-dione (solvent red 168) in an amount of about 35 wt. %, said fuel comprising sucrose (10) in amount of about 14 wt. % and granulated sucrose having a particle size of 350 to 600 microns in an amount of about 14 wt. %, said coolant comprises magnesium carbonate in an amount of about 16 wt. %, and said binder comprises polyvinyl alcohol or nitrocellulose in an amount of about 2 wt. %.

14. The composition of claim 1, wherein said composition is essentially free of nitrogen-based flame retardants.

15. The composition of claim 1, wherein said composition is adapted for use in a smoke producing grenade.

16. A process for producing a low-toxicity red smoke generating grenade, comprising: mixing an oxidizer; a non-sulfur fuel, wherein said fuel comprises a mixture of sucrose having a particle size range of 10 to 100 microns and further includes sucrose having a particle size range of 300 to 650 microns; at least one anthracene or anthraquinone-based red dye; a coolant; and a non-sugar binder to form a mixture; loading said mixture into a body as a solid charge; loading an ignition composition into said body; sealing said body; and attaching an igniter to said body to form a smoke grenade.

17. The process of claim 16, wherein said mixing is done using a planetary mixer or a fluidized bed mixer.

18. The process of claim 16, wherein each of said loading was completed at 1500 to 2500 psi, or about 15,000 lb dead load.

19. The process of claim 16, wherein said mixture comprises said oxidizer in an amount of 18 to 35 wt. %, said fuel in an amount of 20 to 50 wt. %, said red dye in an amount of 27 to 50 wt. %, said coolant in an amount of 8 to 25 wt. %, and said binder in an amount of 1 to 5 wt. %.

20. The process of claim 16, wherein said red dye is selected from the group consisting of 1-(Cyclohexylamino)anthracene-9,10-dione (solvent red 168); 1-Isopropylamino-9,10-anthraquinone (solvent red 169); and mixtures thereof.

21. The process of claim 16, wherein said mixture is essentially free of nitrogen-based flame retardants.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention together with other objects, features, aspects, and advantages thereof will be clearly understood from the following in conjunction with the accompanying drawing.

(2) FIG. 1 depicts the burn time of a smoke grenade relative to the amounts of incorporated granulated sugar.

SUMMARY OF THE INVENTION

(3) The present invention is directed to a novel, environmentally friendly and low toxicity red smoke generating composition comprising at least one red dye, a coolant, an oxidizer, a binder, and a non-sulfur particulate fuel that is also a burn-control agent having at least one particle size distribution.

(4) In a further aspect of the present invention, there is provided a method of producing the red smoke generating composition and incorporating the composition into a smoke grenade.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

(5) The present invention is directed toward a novel environmentally-friendly and low-toxicity red smoke generating composition comprising at least one red dye, and a method of manufacturing the novel environmentally-friendly and low-toxicity red-smoke-producing composition of the present invention.

(6) The invention relates to a smoke-producing pyrotechnic composition and more particularly, is related to generally cool-burning, non-toxic and non-corrosive smoke producing compositions, which incorporate:

(7) Oxidizera presently preferred oxidizer is potassium chlorate (KClO.sub.3).

(8) Non-Sulfur Fuela low energy, sugar-based fuel that also minimizes heat and flame produced. Such fuels are free of sulfur and are selected from the group consisting of starch, dextrose, lactose, sucrose, and mixtures thereof.

(9) Red Dyea sublimable and/or evaporative organic coloring substance which produces a red smoke as a result of the dye undergoing a phase change.

(10) Coolantcoolant prevents excessive decomposition of the dye, and also acts as a buffer for the KClO.sub.3. Suitable coolant is selected from sodium bicarbonate, magnesium carbonate, and the mixtures thereof. Preferably the coolant is magnesium carbonate.

(11) Non-Sugar Bindernitrocellulose or a polymer binder.

(12) Additives (optional)terephthalic acid or stearic acid.

(13) An ideal dye material for this application transforms sublimes directly from the solid phase to the gas phase with little or no intermediate liquid phase. The direct transformation to a gas enhances the likelihood of the dye molecules escaping from the solid matrix made of fuel, oxidizer, and dye to the external environment without the dye molecules reaching an undesirably high temperature. Thus, dyes are sought for the composition that have the property of sublimation at increased temperatures and normal pressures.

(14) The dyes, which may be used in this invention corresponding to the color standard FED-STD-595C color chip, are listed by the Society of Dyers and Colorists in dye classification materials according to chemical structure, and include the following:

(15) TABLE-US-00001 TABLE 1 Chemical compositions of dyes suitable for use in in red smoke-producing compounds of the present invention Cl Name CAS # Trade Name Chemical Name Solvent Red 1 1229-55-6 Anasol Red SG amethoxybenzenazo--naphthol Solvent Red 3 6535-42-8 Anasol Brown DPN 4-(4-ethoxyphenyl)azo-1-naphthol Solvent Red 4 2653-64-7 Anasol Bordeaux DNN 1-(1-Naphthylazo)-2-naphtnol Solvent Red 23 85-86-9 Anasol Scarlet Y 1-(4-(Phenyldiazenyl)phenyl)azonaphlen-2-ol Solvent Red 24 85-83-6 Anasol Red OB 1-((2-Methy1-4-((2-methlphenyl)azo)phenyl)azo)-2- naphthalenol Solvent Red 26 4477-79-6 Anasol Red DTXB 1-[[2,5-dimethyl-4-[[(2-methylphenyl)azo]phenyl]azo]-2- Naphthalenol Solvent Red 27 1320-06-5 Anasol Red DXXN 1-[[4-[(dimethylphenyl)azo]dimethylphenyl]azo]-2- Naphthalenol Solvent Red 49 509-34-2 Anasol Red RBB 9-(9H)xanthen]-3-one,3,6-bis(diethylamino)- Spiro[isobenzofuran-1(3H) Solvent Red 52 81-39-0 Anasol Red BL 3-Methyl-6-(p-toluidino)-3H-dibenz[f,ij]isoquinoline- 2,7-dione Solvent Red 111 82-38-2 Anasol Red KMA 1-(Methylamino)anthraquinone Solvent Red 135 71902-17-5 Anasol Red GG 8,9,10,11-Tetrachloro-12-phthaloperinone Solvent Red 164 71819-51-7 C.I. Solvent Red 164 1-[[2,5-dimethy1-4-[(2-methylphenl)azo]-phenyl]azo]- 2-naphthol Solvent Red 168 71832-19-4 Abcol red 168 1-(Cyclohexylamino)anthracene-9,10-done Solvent Red 169 27354-18-3 AMaplast Red PC 1-isopropylamino-9,10-anthraquinone Solvent Red 179 6829-22-7 Macrolex Red E2G 14H-Benz(4,5)isoquino(2,1-a)perimidin-14-one Solvent Red 207 10114-149-5 Anasol Red CHA 1,5-bis[(3-methylphenyl)amino]anthraquinone

(16) The present inventive red smoke generating composition includes at least one anthracene or anthraquinone-based red dye selected from Table 1. The red dye is selected from the group consisting of: 1-(Methylamino)anthraquinone (solvent red 111); 1-(Cyclohexylamino)anthracene-9,10-dione (solvent red 168); 1-Isopropylamino-9,10-anthraquinone (solvent red 169); 1,5-bis[(3-methylphenyl)amino]anthraquinone (solvent red 207); and mixtures thereof. Preferably, the red dye is selected from the group consisting of 1-(Cyclohexylamino)anthracene-9,10-dione (solvent red 168); 1-Isopropylamino-9,10-anthraquinone (solvent red 169); and mixtures thereof. Specifically, in the form of dry weight, the inventive red smoke generating composition includes at least one red dye in the amount of 27 to 50 wt. %, and preferably about 35 wt. % of the red smoke composition.

(17) The compositions of the present invention also incorporate at least one binder to provide the desired consistency. A binding agent from the group of the halogen-free thermoplastics can be used for the physical stabilization of the mixture of the pyrotechnic smoke-producing composition. The binding agent is selected from the group consisting of polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl ester, polyvinyl ether, or mixtures thereof. Preferably, the binder is either nitrocellulose or polyvinyl alcohol as they result in a decreased solid residue within the burned grain and produce only a small energy output upon combustion. This is important in avoiding very high-energy outputs, high temperatures, and flames, which render smoke producing compositions dangerous and difficult to handle. Nitrocellulose, if used, is used in a solution of 6 to 12% nitrocellulose dissolved in acetone. Accordingly, no sugar substance is used as a binder, as sugar in excess to the fuel of the present invention may cause insufficient burn and reduce color strength.

(18) The composition of the present invention also includes one or more oxidizer compounds. It is found that potassium chlorate (KClO.sub.3) is an efficient oxidizer and produces good results when coupled with the fuel and previously mentioned nitrogen-rich compounds.

(19) The present invention includes a fuel. The fuel is preferably a relatively low energy fuel similar to the binder. It is also preferred that the fuel produce gaseous reaction products capable of carrying the smoke producing agent into the environment. Preferably the fuel is a sugar. Some suitable fuels include starch, dextrose, and polyhydroxylic compounds such as lactose and sucrose. It has been found that depending on the choice of the red dye, an applicable fuel is either one type of sugar having one particle size distribution, or a mixture of sugars having two distinct particle size distributions to effectively control the burn time of the red smoke generating composition from 50 to 90 seconds, an acceptable range for an M18 smoke grenade. Preferably, if one type of sugar is used, the sugar fuel is in the amount of 20 to 50 wt. % of the red smoke composition, and comprises sucrose having a particle size of 10 to 100 microns (10). Most preferably, the 10 sucrose comprises about 28 wt. % of the red smoke composition. If a mixture of sugars is used in the red smoke composition, the sugar comprises a mixture of sucrose having a particle size of 10 to 100 microns (10), and sucrose having a particle size of 300 to 650 microns (granulated). Preferably, the 10 sugar is present in the amount of 10 to 25 wt. % of the red smoke composition, and the granulated sugar (300 to 650 microns) is present in the amount of 10 to 25 wt. % of the red smoke composition. Most preferably, the 10 sucrose comprises about 14 wt. % of the red smoke composition, and the granulated sucrose also comprises about 14 wt. % of the red smoke composition. The ratio of the 10 sugar to the granulated sugar may range from 1:14 to 14:1.

(20) Other materials are also added to produce specific desirable results. One suitable material is magnesium carbonate. Magnesium carbonate acts as a buffer, which prevents autocatalytic decomposition of the KClO.sub.3. Magnesium carbonate also functions as a coolant when the smoke-producing composition combusts. Alternatively, sodium bicarbonate can be used. Another useful additive in the present invention is aluminum. In some cases, atomized aluminum can provide additional thermal conductivity within the composition. This results in more uniform heat transfer and ignition of the fuel.

(21) In general, the ingredients of the composition may be within the ranges indicated in Table 2:

(22) TABLE-US-00002 TABLE 2 Ingredient ranges of the pyrotechnic smoke producing composition of the present invention Percent by Weight Materials (in dry state), % Potassium Chlorate 18 to 35 Sugar (Fuel) 20 to 50 Dye 27 to 50 Magnesium Carbonate 8 to 25 Nitrocellulose 1 to 5

(23) It must be noted that essentially no flame retardant is used, and specifically, no nitrogen-based flame retardant is used. Flame retardants would adversely affect the red color strength of the smoke, as well as prolong the burn time to outside of the 50 to 90 second range for the M18 smoke grenade. The burn rate is controlled by the coolant removing the need of a flame retardant.

EXAMPLE

(24) A series of mixtures were made using white smoke formulation as a baseline (Table 3), replacing part or all of the 10 sugar having an average particle size of 60.91 microns, with granulated sugar having an average particle size of 330.82 microns. The ratio of 10 to granulated sugar varied between 14:0 and 0:14 while the other components remained constant throughout the experiments with respect to the quantity and lot. A Sympatec HELOS laser diffraction particle size analyzer (Sympatec, Clausthal, Germany) was used to measure particle size of the sugar.

(25) TABLE-US-00003 TABLE 3 Baseline Pyrotechnic Smoke Composition Materials Percent by Weight % KClO.sub.3 23 Sugar (sucrose, 10X) 14 Terephthalic Acid (TA) 43 Pentaerythritol (PE) 15 MgCO.sub.3 3 Polyacrylic Rubber 2

(26) Typical pyrotechnic mixing procedures were observed when blending components for all mixtures in a Hobart planetary mixer (Hobart Corporation; Troy, Ohio). Acetone was used as the solvent for the polyacrylic rubber binder and as a mixing medium. The polyacrylic rubber was dissolved in a minimum amount of acetone (approximately 500 ml) before being used to wet the other components of the mixture. Acetone was added as needed to wet the other components of the mixture and to achieve the proper consistency for mixing. Mixing was accomplished using an electrically grounded planetary mixer. When sufficient acetone had evaporated leaving the residual material a damp powder, the mixture was removed from the mixing bowl and placed in a tray. The mixture was then transported to a forced air oven and allowed to dry for a minimum of 24 hours at 140 F.

(27) Ten grams of the dried mixture were hand pressed into small aluminum containers using the step-faced ram. The step on the ram had a depth of 0.375 inch. and a diameter of 0.35 inch. The dimensions of the aluminum container were 1.13 inches inner diameter and 2.21 inches in depth. One gram of the ignition composition given in Table 4 was added to the indentation left by the step-faced ram. The aluminum container was then placed in a Carver Laboratory Press and consolidated with the flat faced ram at 1800 lb. dead load. Based on the dimensions of the container this consolidation force was equivalent to 1800 psi. A container lid with a centered 0.1875 in. diameter port was attached using a sheet metal screw. Initiation was achieved by a small piece of quickmatch (MIL-Q-378B).

(28) TABLE-US-00004 TABLE 4 Ignitions Composition Used in Experiments Materials Percent by Weight % KNO.sub.3 67.35 Ti 11.23 Al 8.16 Si 6.12 S 2.04 C 5.10

(29) Table 5 displays the various sugar ratios in the formulation and burn times for the experiments conducted. A minimum of ten trials was performed for each formulation.

(30) TABLE-US-00005 TABLE 5 Burn Times Resulting from Increasing Percentage of Granulated Sugar Granulated Sugar 10X Confectioners' Sugar (% Weight) (% Weight) Average Burn(s) 0 14 25.05 2 12 26.38 3 11 27.68 4 10 28.33 6 8 30.11 8 6 32,55 9 5 34.14 12 2 37.33 14 0 36.82

(31) Table 5 and FIG. 1 clearly show that when the 10 was replaced with granulated sugar, the burn time was decreased by 32% in this experimental configuration. All test items displayed reliable ignition and produced smoke at a rate consistent with the formulation. As evidenced by a R.sup.2 value of 0.9755 in FIG. 1, a linear approximation of the burn time as a function of sugar ratio served as a reasonable model.

Full Scale Production

(32) For full-scale production the ingredients were mixed using a Glatt fluidized air bed mixer, with a polyvinyl alcohol PVA binder in a water solution. Specifically, the ingredients were weighed to 0.1 g of the desired amount. The sugar, dye, magnesium carbonate, and potassium chlorate were added to the bowl of the Glatt mixer. After 5 minutes of the mixing, the binder was added to the Glatt mixer bowl via spraying for 15 minutes. The mixing operation produced powder and small granules of the smoke composition. The powder was either stored or taken to the pressing operation immediately.

(33) The formulations prepared in the Glatt mixer were then pressed and loaded as follows: Press 1: 100 g of the smoke composition at 15,000 lb dead load; Press 2: 100 g of the smoke composition at 15,000 lb dead load; and Press 3: 100 g of the smoke composition and 5 g of a starter composition at 15,000 lb dead load.

(34) Five grenades were produced for this phase of testing, and were loaded in the same manner as the standard M18 grenades. Four slugs were pressed at about 5500 lb maximum and reconsolidated at 8500500 lb. Each slug was approximately 65 g. The grenades were loaded in the following order: smoke slug, smoke slug, starter patch, smoke slug, starter patch, and smoke slug. The loading was completed at 1500 to 2500 psi, preferably 2300 psi.

(35) Table 6 shows the formulation of the five grenades. Two 1000 g batches of formulation were produced. The mix was pressed into 65 g slugs.

(36) TABLE-US-00006 TABLE 6 Primary Red Formulation Material Amount (%) Amount (g) Solvent Red 169 35.0 350.0 Potassium chlorate 21.0 210.0 Magnesium carbonate 16.0 160.0 Sugar, 10X 28.0 280.0 PVA (BMS CEL 06325) 2.0 333.0

(37) The grenades produced with the primary red formulation had an average burn time of 55.62.3 s. No flaming occurred during this test.

(38) A secondary red smoke formulation was also produced and tested using the above mentioned methods. Two 1000 g batches of this type were made using the formulation listed in Table 7.

(39) TABLE-US-00007 TABLE 7 Secondary Red Formulation Material Amount (%) Amount (g) Solvent Red 168 35.0 350.0 Potassium chlorate 21.0 210.0 Magnesium carbonate 16.0 160.0 Sugar, 10X 14.0 140.0 Sugar, granulated 14.0 140.0 PVA (BMS CEL 06325) 2.0 333.0

(40) The grenades produced with the secondary red formulation had an average burn time of 71 seconds.

(41) An Alternative secondary red formulation was also made:

(42) TABLE-US-00008 TABLE 8 Alternative Red Formulation Material Amount (%) Amount (g) Solvent Red 168 30.0 90.0 Potassium chlorate 21.0 63.0 Magnesium carbonate 21.0 63.0 Sugar, 10X 14.0 42.0 Sugar, granulated 14.0 42.0 Nitrocellulose binder 2.0 6.0

(43) The average burn time for the above formulation was 61 seconds.

(44) The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.