US5487851A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite gun propellant processing technique
Assignee: Northrop Grumman Innovation Systems LLC
•
Filing: 1993-12-20
•
Granted: 1996-01-30
•
Expires: 2013-12-20
Abstract
Abstract A continuous extrusion process for manufacturing composite gun propellant is disclosed. The disclosed process is particularly suitable for preparing gun propellant formulations based upon a cellulose ester binder. In the process, the binder ingredients are dissolved in an organic solvent and then pumped directly into a twin-screw extruder. The other ingredients, except the oxidizer, may optionally be dissolved in the organic solvent prior to introduction into the twin-screw extruder. The oxidizer is dried, ground, and also fed dry to the twin-screw extruder. In the extruder, the materials are thoroughly mixed and the solvent is reduced to sufficient level for direct extrusion through the desired dies.
Inventors
- 👤 David R. Dillehay
- 👤 David W. Turner
- 👤 Horace L. Wingfield, III
- 👤 James A. Blackwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:53
CPC Classifications
C; C06; C06B; C06B21/00; C06B21/0033; C06B21/0075; C06B45/00; C06B45/04; C06B45/06; C06B45/10; C06B45/105
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
91 words
A method of making composite gun propellant comprising the steps of: (a) introducing a lacquer solution into a twin-screw extruder, said lacquer solution containing a quantity of cellulose ester binder and nitrocellulose; (b) adding a quantity of dry oxidizer to the twin-screw extruder, said oxidizer having a weight-mean-diameter particle size of less than about 5 microns; and (c) extruding the composite gun propellant with the twin-screw extruder, said extruding step including the steps of mixing the dry oxidizer and the lacquer solution and removing excess solvent from the oxidizer/lacquer solution mixture.
Claim 2
Independent Claim
91 words
A method of making composite gun propellant comprising the steps of: (a) introducing a lacquer solution into a twin-screw extruder, said lacquer solution containing a quantity of cellulose ester binder and nitrocellulose; (b) adding a quantity of dry oxidizer to the twin-screw extruder, said oxidizer having a weight-mean-diameter particle size of less than about 5 microns; and (c) extruding the composite gun propellant with the twin-screw extruder, said extruding step including the steps of mixing the dry oxidizer and the lacquer solution and removing excess solvent from the oxidizer/lacquer solution mixture.
Claim 3
Dependent Claim
24 words
A method of making composite gun propellant as defined in claim 1, wherein the oxidizer is selected from HMX, RDX, CL-20, and mixtures thereof.
Claim 4
Dependent Claim
35 words
A method of making composite gun propellant as defined in claim 1, wherein the oxidizer has a weight percent in the composite gun propellant in the range from about 70 to about 80 weight percent.
Claim 5
Dependent Claim
28 words
A method of making composite gun propellant as defined in claim 1, further comprising the step of introducing a quantity of stabilizer and plasticizer into the twin-screw extruder.
Claim 6
Dependent Claim
24 words
A method of making composite gun propellant as defined in claim 1, wherein the lacquer solution further contains a quantity of stabilizer and plasticizer.
Claim 7
Dependent Claim
29 words
A method of making composite gun propellant as defined in claim 1, wherein the cellulose ester binder is selected from cellulose acetate, cellulose acetate butyrate and cellulose acetate propionate.
Claim 8
Dependent Claim
37 words
A method of making composite gun propellant as defined in claim 1, wherein the cellulose ester binder has a weight percent in the composite gun propellant in the range from about 10 to about 15 weight percent.
Claim 9
Dependent Claim
39 words
A method of making composite gun propellant as defined in claim 1, wherein the plasticizer is an energetic plasticizer having a weight percent in the composite gun propellant in the range from about 5 to about 10 weight percent.
Claim 10
Dependent Claim
36 words
A method of making composite gun propellant as defined in claim 8, wherein the plasticizer is selected from bis(2,2-dinitropropyl)acetal/bis(2,2-dinitropropyl)formal (BDNPF/BDNPA), trimethylolethanetrinitrate (TMETN), triethyleneglycoldinitrate (TEGDN), diethyleneglycoldinitrate (DEGDN), nitroglycerine (NG), butanetrioltrinitrate (BTTN), alkyl nitratoethylnitramines (NENA's), and mixtures thereof.
Claim 11
Dependent Claim
39 words
A method of making composite gun propellant as defined in claim 1, wherein the plasticizer is an inert plasticizer having a weight percent in the composite gun propellant in the range from about 5 to about 10 weight percent.
Claim 12
Dependent Claim
34 words
A method of making composite gun propellant as defined in claim 10, wherein the plasticizer is selected from triacetin, acetyltriethylcitrate (ATEC), dioctyladipate (DOA), isodecylperlargonate (IDP), dioctylphthalate (DOP), dioctylmaleate (DOM), dibutylphthalate (DBP), and mixtures thereof.
Claim 13
Dependent Claim
25 words
A method of making composite gun propellant as defined in claim 1, further comprising the step of applying a temperature profile along the twin-screw extruder.
Claim 14
Dependent Claim
40 words
A method of making composite gun propellant as defined in claim 1, wherein the twin-screw extruder contains a vacuum port and wherein the method further comprises the step of applying a vacuum to the vacuum port to collect solvent vapors.
Claim 15
Dependent Claim
20 words
A method of making composite gun propellant as defined in claim 1, wherein the composite gun propellant is extruded horizontally.
Claim 16
Dependent Claim
21 words
A method of making composite gun propellant as defined in claim 1, wherein the lacquer solution contains a mixture of solvents.
Claim 17
Dependent Claim
30 words
A method of making composite gun propellant as defined in claim 15, wherein the mixture of solvents is selected from an organic ester, organic ketone, organic alcohol, and mixtures thereof.
Claim 18
Dependent Claim
28 words
A method of making composite gun propellant as defined in claim 15, wherein the mixture of solvents is selected from ethyl acetate, acetone, ethyl alcohol, and mixtures thereof.
Claim 19
Dependent Claim
25 words
A method of making composite gun propellant as defined in claim 1, further comprising the step of cutting the extruded composite gun propellant into pellets.
Claim 20
Dependent Claim
23 words
A method of making composite gun propellant as defined in claim 18, further comprising the step of drying the composite gun propellant pellets.
Claim 21
Dependent Claim
32 words
A method of making composite gun propellant as defined in claim 19, further comprising the step of glazing the composite gun propellant pellets with graphite to prevent static charges and improve packing.
Claim 22
Independent Claim
168 words
A method of making composite gun propellant comprising the steps of: (a) introducing a lacquer solution into a twin-screw extruder, said lacquer solution comprising: a cellulose ester binder having a weight percent in the composite gun propellant in the range from about 10 to about 15 weight percent, and nitrocellulose having a weight percent in the composite gun propellant in the range from about 2 to about 5 weight percent, wherein the foregoing ingredients are dissolved in a solvent; (b) adding a quantity of dry oxidizer selected from HMX, RDX, CL-20, and mixtures thereof to the twin-screw extruder, said oxidizer having a weight-mean-diameter particle size of less than about 5 microns, said oxidizer having a weight percent in the composite gun propellant in the range from about 70 to about 80 weight percent; and (c) extruding the composite gun propellant with the twin-screw extruder, said extruding step including the steps of mixing the dry oxidizer and the lacquer solution and removing excess solvent from the oxidizer/lacquer solution mixture.
Claim 23
Independent Claim
168 words
A method of making composite gun propellant comprising the steps of: (a) introducing a lacquer solution into a twin-screw extruder, said lacquer solution comprising: a cellulose ester binder having a weight percent in the composite gun propellant in the range from about 10 to about 15 weight percent, and nitrocellulose having a weight percent in the composite gun propellant in the range from about 2 to about 5 weight percent, wherein the foregoing ingredients are dissolved in a solvent; (b) adding a quantity of dry oxidizer selected from HMX, RDX, CL-20, and mixtures thereof to the twin-screw extruder, said oxidizer having a weight-mean-diameter particle size of less than about 5 microns, said oxidizer having a weight percent in the composite gun propellant in the range from about 70 to about 80 weight percent; and (c) extruding the composite gun propellant with the twin-screw extruder, said extruding step including the steps of mixing the dry oxidizer and the lacquer solution and removing excess solvent from the oxidizer/lacquer solution mixture.
Claim 24
Dependent Claim
29 words
A method of making composite gun propellant as defined in claim 21, wherein the cellulose ester binder is selected from cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate.
Claim 25
Dependent Claim
73 words
A method of making composite gun propellant as defined in claim 21, further comprising the step of introducing a quantity of stabilizer and plasticizer into the twin-screw extruder, said stabilizer having a weight percent in the composite gun propellant in the range from about 0.2 to about 1 weight percent and said plasticizer having a weight percent in the composite gun propellant in the range from about 5 to about 10 weight percent.
Claim 26
Dependent Claim
63 words
A method of making composite gun propellant as defined in claim 21, wherein the lacquer solution further comprises: a stabilizer having a weight percent in the composite gun propellant in the range from about 0.2 to about 1 weight percent, and a plasticizer having a weight percent in the composite gun propellant in the range from about 5 to about 10 weight percent.
Claim 27
Dependent Claim
19 words
A method of making composite gun propellant as defined in claim 21, wherein the plasticizer is an energetic plasticizer.
Claim 28
Dependent Claim
36 words
A method of making composite gun propellant as defined in claim 25, wherein the plasticizer is selected from bis(2,2-dinitropropyl)acetal/bis(2,2-dinitropropyl)formal (BDNPF/BDNPA), trimethylolethanetrinitrate (TMETN), triethyleneglycoldinitrate (TEGDN), diethyleneglycoldinitrate (DEGDN), nitroglycerine (NG), butanetrioltrinitrate (BTTN), alkyl nitratoethylnitramines (NENA's), and mixtures thereof.
Claim 29
Dependent Claim
19 words
A method of making composite gun propellant as defined in claim 21, wherein the plasticizer is an inert plasticizer.
Claim 30
Dependent Claim
34 words
A method of making composite gun propellant as defined in claim 27, wherein the plasticizer is selected from triacetin, acetyltriethylcitrate (ATEC), dioctyladipate (DOA), isodecylperlargonate (IDP), dioctylphthalate (DOP), dioctylmaleate (DOM), dibutylphthalate (DBP), and mixtures thereof.
Claim 31
Dependent Claim
25 words
A method of making composite gun propellant as defined in claim 21, further comprising the step of applying a temperature profile along the twin-screw extruder.
Claim 32
Dependent Claim
40 words
A method of making composite gun propellant as defined in claim 21, wherein the twin-screw extruder contains a vacuum port and wherein the method further comprises the step of applying a vacuum to the vacuum port to collect solvent vapors.
Claim 33
Dependent Claim
20 words
A method of making composite gun propellant as defined in claim 21, wherein the composite gun propellant is extruded horizontally.
Claim 34
Dependent Claim
21 words
A method of making composite gun propellant as defined in claim 21, wherein the lacquer solution contains a mixture of solvents.
Claim 35
Dependent Claim
30 words
A method of making composite gun propellant as defined in claim 32, wherein the mixture of solvents is selected from an organic ester, organic ketone, organic alcohol, and mixtures thereof.
Claim 36
Dependent Claim
28 words
A method of making composite gun propellant as defined in claim 32, wherein the mixture of solvents is selected from ethyl acetate, acetone, ethyl alcohol, and mixtures thereof.
Claim 37
Dependent Claim
25 words
A method of making composite gun propellant as defined in claim 21, further comprising the step of cutting the extruded composite gun propellant into pellets.
Claim 38
Dependent Claim
23 words
A method of making composite gun propellant as defined in claim 35, further comprising the step of drying the composite gun propellant pellets.
Claim 39
Dependent Claim
32 words
A method of making composite gun propellant as defined in claim 36, further comprising the step of glazing the composite gun propellant pellets with graphite to prevent static charges and improve packing.
Claim 40
Independent Claim
144 words
A method of making composite gun propellant comprising the steps of: (a) drying a quantity of RDX; (b) grinding the RDX to a weight-mean-diameter particle size of less than about 5 microns; (c) preparing a lacquer solution by dissolving a quantity of cellulose ester, nitrocellulose, ethyl centralite, a liquid coupling agent, and an energetic plasticizer in a solvent containing acetone; (d) pumping the lacquer solution into a twin-screw extruder; (e) introducing the dry RDX to the twin-screw extruder; (f) extruding the composite gun propellant with the twin-screw extruder, said extruding step including the steps of mixing the dry RDX and the lacquer solution and removing excess solvent from the RDX/lacquer solution mixture, wherein the composite gun propellant is extruded horizontally; (g) cutting the extruded composite gun propellant into pellets; (h) drying the pellets; and (i) glazing the pellets with graphite to prevent static charges.
Claim 41
Independent Claim
144 words
A method of making composite gun propellant comprising the steps of: (a) drying a quantity of RDX; (b) grinding the RDX to a weight-mean-diameter particle size of less than about 5 microns; (c) preparing a lacquer solution by dissolving a quantity of cellulose ester, nitrocellulose, ethyl centralite, a liquid coupling agent, and an energetic plasticizer in a solvent containing acetone; (d) pumping the lacquer solution into a twin-screw extruder; (e) introducing the dry RDX to the twin-screw extruder; (f) extruding the composite gun propellant with the twin-screw extruder, said extruding step including the steps of mixing the dry RDX and the lacquer solution and removing excess solvent from the RDX/lacquer solution mixture, wherein the composite gun propellant is extruded horizontally; (g) cutting the extruded composite gun propellant into pellets; (h) drying the pellets; and (i) glazing the pellets with graphite to prevent static charges.
Claim 42
Dependent Claim
31 words
A method of making composite gun propellant as defined in claim 38, wherein the lacquer solution contains a mixture of solvents selected from ethyl acetate, acetone, ethyl alcohol, and mixtures thereof.
Claim 43
Dependent Claim
36 words
A method of making composite gun propellant as defined in claim 38, wherein the plasticizer is selected from bis(2,2-dinitropropyl)acetal/bis(2,2-dinitropropyl)formal (BDNPF/BDNPA), trimethylolethanetrinitrate (TMETN), triethyleneglycoldinitrate (TEGDN), diethyleneglycoldinitrate (DEGDN), nitroglycerine (NG), butanetrioltrinitrate (BTTN), alkyl nitratoethylnitramines (NENA's), and mixtures thereof.
Claim 44
Dependent Claim
25 words
A method of making composite gun propellant as defined in claim 38, further comprising the step of applying a temperature profile along the twin-screw extruder.
Claim 45
Dependent Claim
40 words
A method of making composite gun propellant as defined in claim 38, wherein the twin-screw extruder contains a vacuum port and wherein the method further comprises the step of applying a vacuum to the vacuum port to collect solvent vapors.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-29 | 1999-07-31 | 2000-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-29 | 2003-07-31 | 2004-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-29 | 2007-07-31 | 2008-01-30 | $7700.00 | Window Closed / Lapsed |