US3956038A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for obtaining coated pyrotechnic compositions
Assignee: Government of France
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Filing: 1974-03-14
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Granted: 1976-05-11
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Expires: 1994-03-14
Abstract
Abstract Pyrotechnic compositions having a decreased susceptibility to external influences are obtained by suspending pyrotechnic particles in a dilute solution of a coating polymer and adding a second polymer which is more soluble in the solvent, so that microdroplets of the coating polymer are formed, completely enclosing the pyrotechnic particles. The coated particles are hardened by exposure to air, optionally in the presence of a hardening catalyst.
Inventors
- 👤 Jean Rene Duguet
- 👤 Marie Louise Sanmartin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:36
CPC Classifications
C; C06; C06B; C06B21/00; C06B21/0033; C06B21/0066; C06B21/0083; C06B35/00; C06B45/00; C06B45/18
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
201 words
A process for preparing a powdered pyrotechnic composition comprising free particles of at least one pyrotechnic substance, all of said particles characterized by having a size less than 500 microns, being coated with a polymeric binder, having a continuous closed curved convex surface, having a minimum sensitivity to friction of 150g., and having a ratio of the extreme dimensions of the particles up to 2/1, said process comprising the steps of: dissolving the coating polymer in an ionic or non-ionic solvent in a concentration of 2 to 20 percent by weight, introducing 10 to 60 percent by weight of a powdered pyrotechnic substance with sufficient agitation to maintain a homogeneous dispersion of the particles in the coating polymer solution, progressively adding with agitation one or more viscous liquid antagonistic polymers for which said solvent has greater affinity than for said coating polymer to obtain a weight concentration between 20 and 60 percent of the total weight of the solvent, polymer and pyrotechnic substance; filtering to separate plasticized particles of coated pyrotechnic substance from the residual liquid phase; washing the separated particles; and hardening the particles by exposure to air or to the heat of an oven for 2 to 3 hours.
Claim 2
Dependent Claim
201 words
A process for preparing a powdered pyrotechnic composition comprising free particles of at least one pyrotechnic substance, all of said particles characterized by having a size less than 500 microns, being coated with a polymeric binder, having a continuous closed curved convex surface, having a minimum sensitivity to friction of 150g., and having a ratio of the extreme dimensions of the particles up to 2/1, said process comprising the steps of: dissolving the coating polymer in an ionic or non-ionic solvent in a concentration of 2 to 20 percent by weight, introducing 10 to 60 percent by weight of a powdered pyrotechnic substance with sufficient agitation to maintain a homogeneous dispersion of the particles in the coating polymer solution, progressively adding with agitation one or more viscous liquid antagonistic polymers for which said solvent has greater affinity than for said coating polymer to obtain a weight concentration between 20 and 60 percent of the total weight of the solvent, polymer and pyrotechnic substance; filtering to separate plasticized particles of coated pyrotechnic substance from the residual liquid phase; washing the separated particles; and hardening the particles by exposure to air or to the heat of an oven for 2 to 3 hours.
Claim 3
Dependent Claim
25 words
A process according to claim 1 wherein the particles of pyrotechnic substance introduced into the coating polymer solution have a size less than 50 microns.
Claim 4
Dependent Claim
14 words
A process according to claim 3 wherein the pyrotechnic substance comprises a primary explosive.
Claim 5
Dependent Claim
14 words
A process according to claim 3 wherein the pyrotechnic substance comprises a secondary explosive.
Claim 6
Dependent Claim
15 words
A process according to claim 3 wherein the pyrotechnic substance comprises oxidizing and reducing particles.
Claim 7
Dependent Claim
14 words
A process according to claim 3 wherein the pyrotechnic substance comprises electrically conducting particles.
Claim 8
Dependent Claim
25 words
A process according to claim 3 wherein the coating polymer is selected from the group consisting of inert rigid, flexible, thermostable, thermoplastic and thermosetting polymers.
Claim 9
Dependent Claim
13 words
A process according to claim 7 wherein the coating polymer is a polyester.
Claim 10
Dependent Claim
14 words
A process according to claim 7 wherein the coating polymer is a polyol diisocyanate.
Claim 11
Dependent Claim
13 words
A process according to claim 9 wherein the coating polymer is a nitrocellulose.
References Cited (Backward Citations)
US3373062A
Cited
US3480488A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-05-11 | 1979-11-10 | 1980-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-11 | 1983-11-10 | 1984-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-11 | 1987-11-10 | 1988-05-11 | $7700.00 | Window Closed / Lapsed |