Title of Invention	"A PYROTECHNIC AEROSOL GENERATING SYNERGETIC COMPOSITION".
Abstract	This invention relates to a pyrotechnic aerosol generating synergetic composition which comprising of 65 to 85% by wt. Red-phosphorus preferably 78 to 82% by wt, 5 to 15% by wt. Potassium nitrate as oxidiser preferably 12 to 15% by weight, 2 to 10% by wt. Phenolic resin as binder preferably 4 to 7% by weight, a diluent and 1 to 5% by wt. Densensitiser.

Full Text

FIELD OF INVENTION This invention relates to a pyrotechnic aerosol generating synergetic composition. PRIOR ART Pyrotechnic compositions have been used for generating aerosol screen. These aerosol screens are formed on the dispersion of the products of combustion, with atmospheric humidity condensing around them. The moisture-laden-particles of combustion absorb incident radiation in specific wave length regions and this property is used for camouflage operations. These aerosol generating composition are generally processes using a fuel, an oxidiser and a binder with need based additives. One of the pyrotechnic composition known in the art, comprises of hexachloroethane, anthracane, magnesium powder and Zinc oxide. The smoke produced with the burning of hexachloroethane is capable of obscuring IR radiation in the near infrared region of electromagnetic spectrum. Primary disadvantage of the above composition is delayed smoke formation because of the burning nature of the composition. Another disadvantage of the above composition is the formation of HCI acidic vapours which are highly toxic in nature. Still another disadvantage of the above composition is that obscuration characteristic of the composition in the 8 to 14 µm wavelength region is not very high (an extinction coefficient of about 0.1 m2/g at-50% RH. Another pyrotechnic composition known in the art, comprises of a mixture of red phosphorus, sodium nitrate, epoxy binder, magnesium powder and other additives. The primary disadvantage of the above composition is high sensitivity to impact and friction. The processing of the composition which involves granulating and pressing in the form of pellets or in-situ, therefore becomes hazardous . Still -another disadvantage of the above composition is the hygroscopicity due to sodium nitrate oxidiser leading to formation of highly toxic phosphene gas . Still another class of pyrotechnic compositions known in the art, are based upon dispersion of carbon particles(which are the combustion products of the composition) in air to screen IR radiation. One such pyrotechnic composition comprises of hexacloroethane / hexaclorobenzene, naphthalene and magnesium powder. Another such composition comprises of potassium perchlorate, hexacloroethane, anthracene, in combination with gunpowder. Still another reported such composition comprises of hexacloroethane, magnesium powder and an energetic binder, glycidyl azide polymer. However all above pyrotechnic composition based upon screening properties of carbon particle, suffer from the following disadvantages:- One of the disadvantage of the above compositions is that these carbon producing pyrotechnic compositions are effective in absorbing radiation in visible and near IR radiation in the wave length region from 0.4 to 1.1 µrn only, and their extinction coefficient in the 3 to 5 and 8 to 14 urn range is low. Another disadvantage of the above three compositions is that these composition take large amount of time to produce smoke screen.. Red-phosphorous based compositions are also known in the art. One such composition comprises of red phosphorous 31 to 47%, alkali metal nitrate 18 to 32%, metal fuel 1 to 5% and polymeric binder 25 to 35%. Another reported smoke composition comprises of red phosphorous 55 to 80%. sodium nitrate 10 to 30%, amnonium nitrata (3 hydroscopic oxidiser) 10 to 30%, light metal, fuel 1 to 5% and synthetic rudoer 1 to 8, The above two red Phosphorous containing pyrotechnic compositions are effective in absorbing radiation in visible and IR radiation in the wave length region from 0.4 to l.i um only, ana their extinction coefficient in the 3 to 5 and 8 to 14 urn range is low. OBJECTS OF PRESENT INVENTION. The orimary odject of the present invention 3.3 to propose a process to arovidea desensitised aerosol oenerating composition with maximum red-Dhosohorous to provide screening both visible and IR region of electromagnetic spectrum. Another object of the present invention is to propose process to provide a aerosol generating composition which effective in obscuring electromagnetic multisoectral emissions the wave length region of 0.4 to 14 µm. Stil another object of the present invention is to propose a process to provide a formulate a aerosol generating composition which is non-hygroscopic. Yet another object of the present invention is to propose a process to provide a aerosol generating composition which is stable on 1ong storage. pelletsation. without posing and hazard. Due to the maximized loading of the composition with red-phosphorous, the obscuration of multi-spectral & visual emissions in the region of 0,4 to 14 pm is complete.DESRIPTION OF THE PROCESS According to this invention there is provided a pyrotechnic aerosol generating synergetic composition which comprising of 65 to 85% by wt. Red-phosphorus preferably 78 to 82% by wt, 5 to 15% by wt. Potassium nitrate as oxidiser preferably 12 to 15% by weight, 2 to 10% by wt. Phenolic resin as binder preferably 4 to 7% by weight, a diluent and 1 to 5% by wt. Densensitiser In accordance with the present invention, the pyrotechnic aerosol generating composition is prepared by a process comprising following steps ::- (a) Drying of red-phosphorous and sieving 65 to 85% by weight, preferably 78-82% by weight of red-phosphorous conforming to specification IS-2012, is dried at around 70C for about 3 hours. It is then sieved through 150pm IS sieve. (bl Preparation of solution of binder and desensitiser Phenolic resin is dissolved in the diluent methyl ethyl ketone and a desensitiser is added to this and the mixture is mixed for 5 minutes. Methyl ethyl ketone serves as a processing and so that the materials can be processed in a semi-solid form suitable for filing into the container. The desensitiser preferably is dibutyl phthalate or dioctyl adipate which is taken in quantity 1 to 5% by weight, preferably 1 to 2.5 by weight. Phenolic resin is taken in quantity 2 to 10% by weight, preferably 4 to 7% by weight. (c) Drying of potassium nitrate Potassium nitrate (KNO3) taken in quantity 5 to 15% by weight, preferably in quantity 12-15% by weight, is dried at around 100°C for about 2 hours and is then ground in a pulveriser. It is then sieved through 125 micron sieve. (d) Preparation of Composition Red-phosphorus dried and sieved as per step (a) above is taken in a mixer bowl and half the quantity of solution of binder and desensitiser in methyl ethyl ketone. prepared as per step (b), is added to the mixer bowl and the mixture is mixed for about 10 minutes. Dried and sieved potassium nitrate as per step (c) is then added the mixture along-with the remaining quantity of the solution of binder and desensitiser in methyl ethyl ketone (step b). The mixing is continued for 15 minutes and the composition is unloaded into an anti-static bowl. It is covered with aluminium foil before taking up casting/filling. (e) Casting In-situ A paper tube, which goes into the ultimate container, is blocked at one end with a perforated disc and cambric cloth. The composition slurry is poured/filled in granular form and pressed into this and kept in a vacuum chamber at 5 mm of Hg for about one hour to drive out the solvent and is further dried in a drier for about 4 hours. SYNERGIC EFFECT The composition of the present invention does not involve mere addition of constituents leading to aggregation of properties. In the present invention different constituents have synergic effects on each other. The combination of red-phosphorus and oxidiser potassium nitrate produces multi-spectral smoke when activated. Phenolic resin holds the two materials together and the desensitiser dibutyl phthalate or dioctyl adipate desensitise the composition against friction and impact. Methyl ethyl ketone serves as a diluent to enable transforming the mixture into a semi-solid form convenient for casting in situ into a paper liner. The process of the present invention will now be illustrated with a working example, which is intended to be a typical example to illustrate the working of the invention and is not intended to be taken restrictively to imply any limitation on the scope of the invention. WORKING EXAMPLE In a 5 liters capacity beaker, 150g phenolic resin is taken and 700ml of diluent methyl ethyl ketone is added and mixed for 15 minutes to achieve homogeneous solution. To this, 60g desensitiser dioctyl odipate is added and mixed for 5 minutes. In a planetary mixer bowl, the dried and sieved red phosphorus 2400 g is taken and 400ml of the above solution is added and mixed for 10 minutes. Further potassium nitrate 450 g dried and sieved to 125 micron IS sieve is added with remaining 300ml of the binder solution and mixing continued for 15 minutes. The composition is then unloaded into an anti-static bowl and covered with aluminium foil before undertaking casting pressure filling in situ. The above composition weighing about 500 g Is then filled into a paper liner and is cast into a tubular mass of outer diameter 76 mm, internal diameter 10mm and length 80 mm, one end of which is closed with perforated disc and cambric cloth. Six such tubular charges may be filled in three kg of composition. The charges are then dried in a vacuum at a pressure of 5 mm of Hg for 1 hour. Further, they are dried in an air drier for 4 hours duration. EVALUATION The composition as prepared above has a Figure of Insensitivity (F of I) of 70 and has a friction sensitivity of 36 kg determined on standard sensitivity equipments. When the tubular charge is ignited using 2 g of igniter composition, kept in a cambric cloth bag in the port, it bursts open and a smoke screen of 6 x 4m is created for a duration not less than 20 s with excellent obscuration in the visible as well as Infra-red regions of the electromagnetic spectrum. The characteristics of the composition are: i) Impact sensitivity : 70 (Figure of Insensitivity) ii) Friction sensitivity : 36 (Insensitive upto - kg) iii) Flame Temperature, (°C) : 1050 iv) Ignition temperature, (°C) : 330 v) Calorimetric value (in air), (Cal/g) : 250 vi) Smoke screen formation, meters : 6x4 (900 g composition), (screen for a duration of not less than 20 s.) viii) Spectral range of effectiveness : 0.4-14 micron ix) Obscuration constants of the composition in various regions of the electromagnetic spectrum expressed in terms of extinction coefficient: A. At 85% RH i) 0.68 m2/g in 0.4 - 0.7 um ii) 0.64 nr/g in 3 - 5 um iii) 0.52 nr/g in 8 -14 µm B. At 45% RH i) 0.58 m2/g in 0.4 - 0.7 µm ii) 0.40 m2/g in 3 - 5 µm iii) 0.27 m2/g in 8 - 14 µm The process described in the present invention is susceptible to adaptations, changes and modification by those skilled in the art. Such adaptations, changes and modifications are intended to be within the scope of the present investigation, which is further set forth by the following claims: WE CLAIM; 1. A pyrotechnic aerosol generating synergetic composition which comprising of 65 to 85% by wt. Red-phosphorus preferably 78 to 82% by wt, 5 to 15% by wt. Potassium nitrate as oxidiser preferably 12 to 15% by weight, 2 to 10% by wt. Phenolic resin as binder preferably 4 to 7% by weight, a diluent and 1 to 5% by wt. Densensitiser. 2. A pyrotechnic aerosol generating composition as claimed in claim 1 wherein diluent is methyl ethyl ketone. 3. A pyrotechnic aerosol generating composition as claimed in claim 1 wherein desensitiser is preferably dibutyl phthalate or diocryl adipate in quantity of preferably 1 to 2.5% by weight. 4. A pyrotechnic aerosol generating composition substantially as herein described and illustrated in the examples. 5. A process for the preparation of pyrotechnic aerosol generating synergetic composition as claimed in claim 1 comprising in the steps of drying red phosphorous at 70C for 3 hours and sieving through 150 micron 19 sieve, drying potassium nitrate at 100C for 2 hours and sewing through 125 microns, mixing of dried and sieved red-phosphorous with half the quantity of the solution of binder and desensitiser in diluent followed with mixing of dried and sieved pottassium nitrate and the remaining quantity of the solution of binder and desensitiser in diluent which is further followed by casting in-situ after vacuum drying.

Documents:

500-del-2001-abstract.pdf

500-del-2001-claims.pdf

500-del-2001-correspondence-others.pdf

500-del-2001-correspondence-po.pdf

500-del-2001-description (complete).pdf

500-del-2001-form-1.pdf

500-del-2001-form-18.pdf

500-del-2001-form-2.pdf

500-del-2001-gpa.pdf