US4241661A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite propellant with surface having improved strain capacity
Assignee: Hercules LLC
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Filing: 1968-12-04
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Granted: 1980-12-30
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Expires: 1988-12-04
Abstract
Abstract The invention is based on the discovery that when at least a part of the initial burning surface of an epoxy cured carboxy terminated rubber type composite propellant is coated with a propellant antioxidant material, an increase in resistance to oxidative hardening and an increase in strain capability is imparted to said surface. The invention provides (1) such a composite propellant coated at an initial burning surface with a propellant antioxidant in an amount sufficient to impart those unexpected improvements, (2) method involving coating the burning surface with the requisite amount of the propellant antioxidant material, and (3) a propellant rocket motor containing the above said propellant. When only a portion of the surface is subject to high strain, e.g. in slot areas, it is sufficient that only that portion of the burning surface be coated.
Inventors
- 👤 Donald E. Elrick
- 👤 Harry Gilbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:56
CPC Classifications
C; C08; C08G; C08G59/00; C08G59/18; C08G59/68; C08G59/681; C08G59/685; C06; C06B; C06B23/00; C06B23/006; C06B45/00; C06B45/04; C06B45/06; C06B45/10; C06B45/12; C08L; C08L63/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
107 words
In a composite propellant wherein the binder component comprises a carboxy terminated rubber selected from the group consisting of elastomeric polymers of at least one conjugated diene containing 4 to 8 carbon atoms and elastomeric polymers of at least one olefin containing 2 to 4 carbon atoms, cured with an epoxide curing agent therefor, the improvement comprising a coating of a propellant antioxidant material on an initial burning surface of said propellant in an amount sufficient to impart to said burning surface an increase in strain capability and an increase in resistance to oxidative hardening and to provide at least about 0.0005 gram/square centimeter of said surface.
Claim 2
Dependent Claim
107 words
In a composite propellant wherein the binder component comprises a carboxy terminated rubber selected from the group consisting of elastomeric polymers of at least one conjugated diene containing 4 to 8 carbon atoms and elastomeric polymers of at least one olefin containing 2 to 4 carbon atoms, cured with an epoxide curing agent therefor, the improvement comprising a coating of a propellant antioxidant material on an initial burning surface of said propellant in an amount sufficient to impart to said burning surface an increase in strain capability and an increase in resistance to oxidative hardening and to provide at least about 0.0005 gram/square centimeter of said surface.
Claim 3
Dependent Claim
28 words
A composite propellant of claim 1 wherein the amount of antioxidant on said surface is within the range of from 0.0005 to 0.1 gram/square centimeter of said surface.
Claim 4
Dependent Claim
37 words
A composite propellant of claim 2 wherein said antioxidant material is a mixture of at least one propellant antioxidant of the free radical decomposer type and at least one propellant antioxidant of the hydroperoxide group decomposer type.
Claim 5
Dependent Claim
15 words
A composite propellant of claim 3 wherein said antioxidant mixture also contains a chelating agent.
Claim 6
Dependent Claim
21 words
A composite propellant of claim 2 wherein said antioxidant material is a mixture of a phenyl-β-naphthylamine, N,N'-bis(1,4-dimethylpentyl)p-phenylenediamine, 4,4'-thio-bis(6-tert-butyl-meta-cresol) and 8 hydroxyquinoline.
Claim 7
Dependent Claim
19 words
A composite propellant of claim 3 wherein said mixture contains at least 8 weight percent of each individual antioxidant.
Claim 8
Dependent Claim
18 words
A composite propellant of claim 2 wherein said antioxidant material is a mixture of phenyl-β-naphthylamine, N,N'-bis(1,4-dimethylpentyl)p-phenylenediamine and thiodiphenylamine.
Claim 9
Dependent Claim
19 words
A composite propellant of claim 2 wherein said antioxidant material is a mixture of phenyl-β-naphthylamine, N,N'-bis(1,4-dimethylpentyl)p-phenylenediamine and 4,4'-thio-bis (6-tert-butyl-meta-cresol).
Claim 10
Dependent Claim
26 words
A composite propellant of claim 2 containing, on a weight basis, from 5-20 percent of said binder component and from 60-90 percent of a solid oxidizer.
Claim 11
Dependent Claim
38 words
A propellant of claim 9 wherein said epoxy curing agent is a mixture of difunctional epoxides and trifunctional epoxides, and wherein the mole ratio of the dioxide to trioxide is within the range of from 15:1 to 1:1.
Claim 12
Dependent Claim
35 words
A propellant of claim 10 wherein said carboxy terminated rubber is a carboxy terminated butadiene, and wherein the mole ratio of epoxy groups to carboxy groups is within the range of from 0.9:1 to 2:1.
Claim 13
Dependent Claim
41 words
A propellant of claim 10 wherein the carboxy terminated rubber is a polymer selected from the group consisting of a carboxy terminated polybutadiene and carboxy terminated polyisobutylene having a molecular weight within the range of from about 1000 to about 20,000.
Claim 14
Dependent Claim
13 words
A propellant of claim 9 wherein said solid oxidizer component is ammonium perchlorate.
Claim 15
Dependent Claim
30 words
A propellant of claim 13 containing from 70 to about 90 weight percent of said ammonium perchlorate and from 5 to about 10 weight percent of a particulate metal fuel.
Claim 16
Dependent Claim
128 words
In a composite rocket motor, wherein the binder system of the propellant comprises a carboxy terminated rubber selected from the group consisting of elastomeric polymers of at least one conjugated diene containing 4 to 8 carbon atoms and elastomeric polymers of at least one olefin containing 2 to 4 carbon atoms, cured with an epoxide curing agent therefor, the improvement comprising a stain of a propellant antioxidant material on an initial burning surface of said propellant in an amount sufficient to impart to said burning surface an increase in strain capability and an increase in resistance to oxidative hardening and to provide at least about 0.0005 gram/square centimeter of said surface; and said propellant having a mass ratio increased as a function of the presence of said stain.
Claim 17
Dependent Claim
128 words
In a composite rocket motor, wherein the binder system of the propellant comprises a carboxy terminated rubber selected from the group consisting of elastomeric polymers of at least one conjugated diene containing 4 to 8 carbon atoms and elastomeric polymers of at least one olefin containing 2 to 4 carbon atoms, cured with an epoxide curing agent therefor, the improvement comprising a stain of a propellant antioxidant material on an initial burning surface of said propellant in an amount sufficient to impart to said burning surface an increase in strain capability and an increase in resistance to oxidative hardening and to provide at least about 0.0005 gram/square centimeter of said surface; and said propellant having a mass ratio increased as a function of the presence of said stain.
Claim 18
Dependent Claim
22 words
In a propellant motor of claim 15, from 0.0005 to 0.01 grams of said stain per square centimeter of said burning surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-30 | 1984-06-30 | 1984-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-30 | 1988-06-30 | 1988-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-30 | 1992-06-30 | 1992-12-30 | $7700.00 | Window Closed / Lapsed |