Method of producing progressively burning artillery propellant powder and agent adapted thereto

• US 4,597,994 A
• Filed: 01/09/1985
• Issued: 07/01/1986
• Est. Priority Date: 07/13/1983
• Status: Expired due to Fees

• Current Assignee: Aktiebolaget Bofors
• Original Assignee: Aktiebolaget Bofors
• Inventors: Schmid, Hermann, Bolinder, Boo
• Primary Examiner(s): Beck, Shrive P.
• Application Number:
  US06/690,072
• Time in Patent Office: 538 Days
• Field of Search: 102/288, 102/290, 102/292, 427/213, 427/221
• US Class Current: 427/213
• CPC Class Codes: C06B 21/0083 Treatment of solid structures, e.g. for coating or impregnating with a modifier compositions therefor C06B23/00
• CPC Class Codes: C06B 23/04 for cooling the explosion gases including antifouling and flash suppressing agents
• CPC Class Codes: C08G 18/4277 Caprolactone and/or substituted caprolactone
• CPC Class Codes: F42B 5/196 Coatings

Abstract

The invention relates to a general method of producing progressively burning deterrent-coated powder, more particularly propellant powder for weapons having barrels. According to the method a film-forming, preferably polymerizable deterrent substance is fed to the powder loosely or dispersed in a liquid phase which is thereafter driven off. The invention also relates to a method of giving a deterrent coating to granular powder or powder cut up in to short pieces (so-called tubular powder) in a fluidized bed. Finally, the invention relates to a special deterrent substance in the form of a water-dispersable polyurethane built up on an aliphatic isocyanate and a caprolacton polyester.

Claims

1. A method of producing a progressively burning deterrent-coated propellant powder for weapons having a barrel which comprises coating the outer surfaces of the said propellant powder with a film-forming deterrent substance by feeding to said powder said deterrent substance dissolved or dispersed in water and, thereafter, driving off said water.

2. The method of claim 1 wherein said powder is rod-shaped tubular powder.

3. The method of claim 1 wherein said deterrent substance is polymerizable.

4. The method of claim 3 wherein said deterrent substance is a water-dispersible polyurethane with a molecular weight between 200 and 600 built up from an aliphatic isocyanate and a caprolactone polyester having the formula:

##STR2## where R=the polymerization initiator.

5. The method of claim 4 wherein said powder is rod-shaped tubular powder.

6. The method of claim 4 wherein said powder is granular powder or tubular powder cut up into shorter lengths;

wherein the powder is coated with the deterrent substance while the powder is kept suspended in a fluidized bed to which the deterrent substance is fed; and

wherein the water is driven off from the powder before the powder is removed from the said fluidized bed.

7. The method of claim 6 wherein the powder is kept suspended in the fluidized bed until all of the deterrent substance attached to the powder has been polymerized.

8. The method of claim 7 wherein fed to the outer surfaces of the powder in the fluidized bed are a number of superimposed deterrent layers, each of which contains, in addition to the film-forming substance and the water, at least one additive selected from the group of coolants, flame dampers, and decoppering agents.

9. The method of claim 8 wherein said additive is present in an amount of up to 80% by weight based upon the amount of finally solid substance.

10. The method of claim 9 wherein said amount is 35-65% by weight.

11. The method of claim 8 wherein said additive is a formaline-based material or titanium dioxide.

12. The method of claim 8 wherein said additive is oxamide or dimethylol urea.

13. The method of claim 1 wherein said coating has a thickness of 2-500 μ

m.

14. The method of claim 1 wherein said deterrent substance is a polymerizable water-urethane dispersion containing tertiary amine blocked carboxyl groups which, during film formation, split off tertiary amine.

15. The method of claim 1 wherein said powder is granular powder or tubular powder cut up into shorter lengths;

wherein the powder is coated with the deterrent substance while the powder is kept suspended in a fluidized bed to which the deterrent substance is fed; and

wherein the water is driven off from the powder before the powder is removed from the said fluidized bed.