US 2007.006861 OA1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2007/0068610 A1 Nickel (43) Pub. Date: Mar. 29, 2007 (54) MICROCRYSTALLINE NITROCELLULOSE Publication Classification PYROTECHNIC COMPOSITIONS (51) Int. Cl. (76) Inventor: Russell R. Nickel, Columbus, MT (US) C06B 45/10 (2006.01) (52) U.S. Cl. ............................................................ 149/19.8 Correspondence Address: PSERIEDER, WOODRUFF & (57) ABSTRACT 12412 POWERSCOURT DRIVE SUTE 200 ST. LOUIS, MO 63131-3615 (US) A. pyrotechnic composition comprising microcrystalline nitrocellulose which is characterized as an ultra low-smoke (21) Appl. No.: 11/469,936 composition. The pyrotechnic composition includes at least one flame coloring agent, and may be produced with or (22) Filed: Sep. 5, 2006 without an optional oxidizing agent, with or without an optional metal powder, with or without an optional chlorine Related U.S. Application Data donor. Upon combustion, the pyrotechnic composition pro duces illuminating emissions having desired colors and (63) Continuation-in-part of application No. 11/058,677, luminosity characteristics with significantly reduced or toxic filed on Feb. 15, 2005. combustion products and Smoke. US 2007/006861.0 A1 Mar. 29, 2007 MCROCRYSTALLINE NITROCELLULOSE may include at least one compound selected from a group PYROTECHNIC COMPOSITIONS consisting of ammonium perchlorate, alkali metal perchlo rates, alkali metal chlorates, alkali metal nitrates and alka CROSS-REFERENCE TO RELATED line earth metal nitrates. Additional fuels may include car APPLICATIONS bon, titanium, titanium alloys, Zirconium, Zirconium alloys, 0001. The present application is a continuation-in-part of iron, alloys of iron, magnesium, alloys of magnesium, U.S. patent application Ser. No. 11/058,677 herein incorpo aluminum and alloys of aluminum. These materials are rated by reference, filed on Feb. 15, 2005 and published as easily solidified with binders, agglomerated, or compressed, U.S. Patent Application Publication No. 2006/0180253 on to form pellets or granules. Aug. 17, 2006. 0008. It is known that pyrotechnic compositions includ ing nitrocellulose as the Sole propellant in a color generating STATEMENT REGARDING FEDERALLY composition are not capable of generating Sufficient tem SPONSORED RESEARCH perature during combustion to produce an acceptable light output and depth of color Suitable for use as a pyrotechnic 0002) Not Applicable. star or other fireworks visual display element. Initially, it was thought that the inability of nitrocellulose to produce BACKGROUND OF THE INVENTION adequate colors was due to the presence of contaminants in 0003. The present invention is related to the manufacture the combustion flame including sodium salts and un-oxi and use of pyrotechnic compositions such as are used in dized carbon, but extensive testing has shown that the lack fireworks and flares for providing an illuminating visual of functionality is mainly due to the low combustion tem display, and in particular to the use of microcrystalline perature inherent to nitrocellulose itself. Even when com nitrocellulose as a fuel component in a pyrotechnic compo pressed to a great degree, nitrocellulose does not produce a sition to provide vivid colors during combustion. Sufficient combustion temperature to generate usable colors or useful luminosity as a fireworks display component by 0004 Nitrocellulose, also known as cellulose nitrate, itself. pyroxylin, colloxylin, Xyloidin, celloidin, and parlodion, is a fast burning, easily ignitable, high-nitrogen energetic mate 0009 Common nitrocellulose is not capable of reaching rial which has been used in Such applications as explosives Sufficient temperatures during combustion to allow the use and as a gun and rocket propellant. Nitrocellulose burns of a variety of color generating salts because the combustion cleanly with non-toxic combustion byproducts. Such as temperature of nitrocellulose does not reach sufficient levels nitrogen, carbon dioxide, and water vapor. In the fireworks to cause the decomposition of the colorant salts into their industry, nitrocellulose is typically utilized as an energetic constituent ions, enabling them to reform into the proper binder in a lacquer form, added to pyrotechnic compositions. color radiating species in combination with free chlorine. To solve this problem, it is known to combine the nitrocellulose 0005 Nitrocellulose is manufactured from cellulose, with additional chemical additives to increase the tempera which has the chemical formula CHOs, and which is the ture of combustion. Typically both oxidizers and fuels are principle structural component of cell walls in higher plants. used for this purpose, and usually in combination with each An almost pure form of cellulose, known as alpha cellulose, other, since adding either an oxidizer or a fuel alone would occurs naturally in cotton fibers. The physical properties of alter the oxygen balance of the pyrotechnic composition, cellulose are a result of an association of cellulose chains thereby lowering the performance. which form crystalline structures called microfibrils, typi 0010. It is further well known that it is advantageous to cally having a diameter of 2-20 nm, a length of between provide free and excess chlorine ions to color generating 100-40,000 nm, and which contain about 2000 cellulose compositions to ensure the prompt and efficient production molecules. Within a plant cell, the orientation of microfibrils of the preferred “mono-chloride' color emitting species. The changes from layer to layer. Often, especially in very strong favored color generating species in pyrotechnic flames is plant cell walls, the microfibrils are arranged screw-like generally considered to be a mono-chloride of an alkali about an axis of the cell, with changes in the turning angle metal or alkaline earth metal. In the past it has been found from layer to layer. to be advantageous to add supplemental chlorine donating 0006 Nitrocellulose is produced by the well known pro compounds to increase the chances of forming the desired cess of nitrating cellulose with a mixture of concentrated mono-chlorides and thus the intended color. Recently, per acids including nitric acid, which has the chemical formula chlorates Such as potassium and ammonium perchlorate HNO. During the resulting chemical process, the nitric acid have been discovered to pose a heath hazard in lower levels converts the cellulose into cellulose nitrate, having the than previously believed. chemical formula of CHO(NO), CHOs (NO), or 0011 Since a majority of chlorine-containing compounds CH, Os(NO), depending on the degree of nitration. Sulfu normally employed in color-generating pyrotechnic compo ric acid generally is used in conjunction with the nitric acid sitions, are either toxic, hazardous, or pose a pollution during the nitrating process to prevent the water produced in hazard, particularly in geographic locations near which the reaction from diluting the concentration of nitric acid. regular fireworks displays are provided, it would be advan 0007 Pyrotechnic and explosive compositions are typi tageous to provide a pyrotechnic composition for use in cally fairly dense mixtures of crystalline salts for flame fireworks and flares which produces illuminating emissions color, crystalline oxidizers, carbonaceous fuels, and pow having desired color and luminosity characteristics while dered metals. The flame coloring agents are commonly the reducing or eliminating harmful or toxic compounds. salts of the metals; barium, strontium, copper, boron, cal 0012 Another problem with the use of nitrocellulose in a cium, potassium, Sodium and lithium. The oxidizing agents pyrotechnic composition is the inherent low density nature US 2007/006861.0 A1 Mar. 29, 2007 of nitrocellulose. The addition of fuels or oxidizers to a such as described in U.S. Pat. No. 6,599,379 B2 to Hiskey pyrotechnic composition containing nitrocellulose may et al. because of the clean burning, low Smoke, low tem serve to increase the density of the composition, but the perature and generally environmentally friendly nature of nitrocellulose molecules remain overall a low density mate conventional nitrocellulose. However, conventional nitro rial. Coloiding and partial dissolution of the pyrotechnic cellulose has the undesirable property of not being able to composition has been employed in pyrotechnic components, attain combustion temperatures which are sufficient to gen as well as propellant applications for many years. The use of erate the vivid and vibrant colors desired in fireworks additional binders, solvents, plasticizers, and coloiding displays without the use of Supplemental energetic oxidiz agents generally only results in slower rate or burn and an ers, fuels, and/or combinations of same. The oxidizers and increase in the Smoke output of the pyrotechnic composition fuels employed with conventional nitrocellulose are the upon combustion, and increases the complexity of the manu same as used in current state of the art fireworks composi facturing process. tions. Thus, the problems inherent in utilizing these oxidiz 0013. Accordingly, it would be advantageous to provide ers and fuel in combination with conventional nitrocellulose a pyrotechnic composition which reduces the requirement remain the same, albeit at a reduced amount. for additional binders or densifying agents, which has a 0020. The present invention serves to remove nearly dense crystalline form, and which provides