Explosive and thermic compositions or charges – Containing inorganic nitrogen-oxygen salt
Reexamination Certificate
1998-10-01
2001-01-30
Rotman, Alan L. (Department: 1612)
Explosive and thermic compositions or charges
Containing inorganic nitrogen-oxygen salt
C546S003000, C546S013000, C546S022000
Reexamination Certificate
active
06179937
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to stabilizers for hydroxylammonium nitrate (HAN), HAN derivatives, and their precursor, hydroxylamine and compositions comprising HAN, an HAN derivative or hydroxylamine. The present invention further relates to stabilized HAN, HAN derivatives and hydroxylamine, as well as stabilized compositions containing HAN, an HAN derivative or hydroxylamine. HAN, HAN derivatives or hydroxylamine and compositions comprising HAN, an HAN derivative or hydroxylamine are stabilized against decomposition by the addition of a stabilizing effective amount of a stabilizer(s) within the scope of the present invention. More specifically, the present invention relates to stabilized compositions, such as liquid propellants (also referred to herein as “LP”) that contain HAN, an HAN derivative or hydroxylamine and a fuel. HAN derivatives referred to within the scope of the present invention are compounds prepared by substituting a functional group on the amine in place of a hydrogen ion—i.e. diethylhydroxylammonium nitrate.
BACKGROUND OF THE INVENTION
HAN, HAN derivatives and hydroxylamine are useful oxidizers in various propellant formulations such as, for example, those used for guns, rockets, satellites, gas generators, and the like. HAN, specifically, is an oxidizer for propellants that has recently become available in commercial quantities. Processes for preparing HAN are set forth in U.S. Pat. Nos. 5,510,097 and 5,258,104. HAN, its derivatives and hydroxylamine have many desirable properties, such as high oxygen content, high water solubility as well as containing no halogen atoms. Unfortunately, the storage stability for HAN, HAN derivatives or hydroxylamine, and compositions containing them has been, and continues to be, a concern for which solutions are sought. The need exists to enhance the storage stability of HAN, HAN derivatives or hydroxylamine and compositions containing them.
Certain stabilizers for HAN, HAN derivatives and hydroxylamine are known. Some have been used to protect compositions containing HAN, HAN derivatives and hydroxylamine from unwanted degradation during storage prior to use. As disclosed in U.S. Pat. No. 3,145,082, chelating agents, such as the tetrasodium salt of ethylenediaminetetraacetic acid (EDTA) have been used as stabilizers for hydroxylamine. The prior art further teaches the use of aminophosphonic acids as stabilizers for HAN-based liquid propellant (LP) compositions. This is set forth in a technical report by R. Hansen et al., entitled “Processes for Assessing the Thermal Stability of HAN-Based Liquid Propellants, Final Report,” BRL-CR-635, Ballistic Research Laboratory, Aberdeen Proving Ground, Md. (Jul., 1990).
There exists a continuing need to develop and provide means for which to provide enhanced stability to HAN, HAN derivatives and hydroxylamine, as well as for compositions comprising these. Being able to accomplish this in a cost-effective fashion is further desirable. The present invention provides a solution to meet the needs described.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to stabilizers for HAN, HAN derivatives and hydroxylamine and compositions comprising these. The present invention further relates to stabilized HAN, HAN derivatives, or hydroxylamine-containing compositions comprising HAN, an HAN derivative or hydroxylamine and an effective stabilizing amount of a stabilizer within the scope of the present invention. The stabilizer is preferably present in said composition in an amount of between approximately 0.0001% wt. to 2% wt. based on the weight of said composition.
Stabilizers which may be employed herein are selected from (a) a pyridine or pyridone salt, or an acid thereof (Type I stabilizers); (b) a diphosphonate or methylenephosphonate salt, or an acid thereof (Type II stabilizers); or (c) a stabilizing mixture of at least one stabilizer selected from each of (a) and (b), above (Type III stabilizers). The stabilizers will be more specifically identified and defined in the detailed description of the invention.
Accordingly, it is an object of the present invention to provide stabilizers for HAN, HAN derivatives and hydroxylamine, and for compositions containing at least one of said HAN, HAN derivative or hydroxylamine.
It is another object of the present invention to provide a stabilized HAN, HAN derivative or hydroxylamine-containing composition comprising said HAN, HAN derivative or hydroxylamine and a stabilizing effective amount of a stabilizer ingredient to provide a storage-stable composition.
Yet a further object of the present invention is to provide a stabilized HAN, HAN derivative or hydroxylamine-containing composition comprising said HAN, HAN derivative or hydroxylamine and a stabilizer, wherein said stabilizer is present in said composition in an amount of between approximately 0.0001% wt. and 2% wt. based upon the weight of said composition.
It is a further object of the present invention to provide a process for stabilizing HAN, HAN derivatives or hydroxylamine against unwanted degradation during storage prior to use, which comprises contacting said HAN, HAN derivative, or hydroxylamine with a stabilizing effective amount of a stabilizer to provide a storage-stable composition.
Still a further object of the present invention is to provide a process for forming a storage-stable composition of HAN, an HAN derivative or hydroxylamine, or propellant formulations containing at least one of said HAN, HAN derivative or hydroxylamine, which comprises mixing a stabilizing effective amount of a stabilizer with a composition comprising HAN, an HAN derivative or hydroxylamine to provide said storage-stable composition.
It is a further object of the present invention to increase the shelf life of HAN, HAN derivatives, and hydroxylamine, and compositions comprising at least one of said ingredients.
The means to achieve these and other objectives of the present invention will be apparent from the following detailed description of the invention and claims.
REFERENCES:
patent: 3145082 (1964-08-01), Rausch et al.
patent: 5258104 (1993-11-01), Crawlfield et al.
patent: 5510097 (1996-04-01), Crawlfield et al.
patent: 5703323 (1997-12-01), Rothgery et al.
Hansen, R., et al., “Processes for Assessing the Thermal Stability of HAN-Based Liquid Propellants, Final Report,” BRL-CR-635, Ballistic Research Laboratory, Aberdeen Proving Ground, Maryland (Jul., 1990).
Bunte Steven W.
Klein Nathan
Leveritt Chares S.
Rothgery Eugene F.
Seefried Carl G.
Clohan, Jr. Paul S.
Kelly Mark D.
Rotman Alan L.
The United States of America as represented by the Secretary of
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