Explosive and thermic compositions or charges – Structure or arrangement of component or product – Solid particles dispersed in solid solution or matrix
Reexamination Certificate
1999-10-12
2001-07-10
Carone, Michael J. (Department: 3641)
Explosive and thermic compositions or charges
Structure or arrangement of component or product
Solid particles dispersed in solid solution or matrix
C149S019600, C149S023000, C149S088000, C149S019900, C149S019400
Reexamination Certificate
active
06258188
ABSTRACT:
BACKGROUND OF THE INVENTION
The U.S. Army MICOM has conducted investigations in the development of fuel-rich gas generator formulations for minimum signature and smokey ducted rockets. The majority of work has primarily involved the incorporation of carbon as a fuel in a binder system based on glycidyl azide polymer (GAP). Goals of the ducted rocket engine formulations include high delivered volumetric heating values, tailorable burning rates and exponents, low temperature sensitivity, good mechanical properties, low combustion chamber temperatures, and good ignitability over a wide temperature range.
SUMMARY OF THE INVENTION
In studies conducted by MICOM, nitramine-containing prepolymers such as ORP-2 and 9-D, T-NIDA were evaluated as alternatives to GAP. These studies show ORP-2 and 9-D, T-NIDA to have superior compatibility and mechanical properties to GAP while still offering the low combustion temperatures which made GAP of interest initially. These formulations also contain zirconium hydride, ZrH
2
, as a fuel additive. ZrH
2
has been demonstrated to improve ignitability relative to standard carbon-containing formulations. Based on the results of initial tests with these ingredients, a formulation range (TABLE 3) has been developed. Examples of formulations derived from this formulation range are outlined below in TABLE 1. These examples demonstrate the theoretical performance [specific impulse, (Isp), impulse density, (IspD), chamber temperature, (Tcham), and exhaust temperature, (Texit)] available with combinations of these ingredients and the resulting theoretical concentration of exhaust products.
DESCRIPTION OF THE PREFERRED EMBODIMENT(s)
Examples of formulations derived from the formulation ranges of Table 3 are shown in Table 1 along with the combustion products and some relative performance characteristics. Table 2 lists additional performance characteristics. The ingredients with abbreviations shown in Table 1, Table2, and Table 3 are identified hereinbelow under “Table: Ingredients Defined” prior to the listing of ingredients set forth in Tables 1-3.
TABLE
Ingredients Defined
ORP-2
a nitramine-containing prepolymer based on
undecanedioc acid as detailed in U.S. Pat. No.
4,916,206 issued to Day and Hani.
CARBON
carbon black
HMDI
hexamethylene diisocyanate
IPDI
Isophorone diisocyanate
N100
a polyfunctional isocyanate which is the reaction product
of hexamethylene diisocyanate and water
ZrH
2
zirconium hydride as fuel additive
DBTDL
dibutyl tin dilaurate, curing catalyst
9-D, T-NIDA
nitramine-containing prepolymer based on
nitraminodiacetic acid, diethylene glycol,
and triethylene glycol.
TABLE 1
INGREDIENT
%
%
%
ORP-2
82.65
78.30
82.65
N100
12.34
11.69
12.34
C
5
0
3
ZrH
2
0
10
2
DBTDL
0.01
0.01
0.01
PERFORMANCE
VALUE
Isp(sec)
140.2
149.8
143.2
IspD
6.7
7.6
6.9
Tcham(K)
999
1105
1024
Texit(K)
664
760
687
EXHAUST
WEIGHT
WEIGHT
WEIGHT
PRODUCT
%
%
%
C
33.31
27.28
31.35
CH
4
0.19
8.54
10.05
CO
0.23
1.56
0.38
CO
2
18.78
17.08
18.83
H
2
0.65
1.57
0.83
H
2
O
22.54
17.21
21.63
N
2
14.29
13.53
14.29
ZrO
2
0
13.
2.64
The theoretical values shown are within the acceptable ranges for the application of these formulations to solid fuel gas generators.
Solid fuel gas generator formulations are also characterized by their theoretical volumetric and gravimetric heating values. Theoretical heating values for the formulations described above in TABLE 1 are outlined in TABLE 2.
TABLE 2
INGREDIENT
%
%
%
ORP-2
82.65
78.3
82.65
N100
12.34
11.69
12.34
C
5
0
3
ZrH
2
0
10
2
DBTDL
0.01
0.01
0.01
PERFORMANCE
VALUE
VHV,
441
425
431
BTU/in3
GHV,
9188
8598
9018
BTU/lb
TABLE 2
INGREDIENT
%
%
%
ORP-2
82.65
78.3
82.65
N100
12.34
11.69
12.34
C
5
0
3
ZrH
2
0
10
2
DBTDL
0.01
0.01
0.01
PERFORMANCE
VALUE
VHV,
441
425
431
BTU/in3
GHV,
9188
8598
9018
BTU/lb
In a comparison with other binder systems (prepolymer with curing agents), it has been determined that energetic nitramine containing binders offer advantages over current ducted rocket engine fuel gas generator formulations and lead to improved overall performance. These advantages include superior compatibility and mechanical properties without adversely affecting low temperature combustion. Because of these advantages and the initial test results which show that combinations of ORP-2 with ZrH
2
, in solid fuel gas generators display improved ignitability relative to standard carbon containing formulations, we claim this combination as unique and more suitable for solid fuel gas generators.
While the present invention is outlined by specifications listed in TABLE 3, it is not intended to be limited specifically to this range. There are many variations possible within the scope of the claims.
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Hatcher Richard C.
Stanley Robert L.
Stephens William D.
Bush Freddie M.
Carone Michael J.
Sanchez Glenda L.
The United States of America as represented by the Secretary of
Tischer Arthur H.
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