Method for making pyrotechnic material and related technology

1. A method for making a pyrotechnic composition, the method comprising:

forming a powder mixture including a metal powder and a binder powder, wherein the binder powder includes an adhesive material and an anticaking material disposed around the adhesive material; and

shearing the binder powder with heat over approximately 120 degrees Fahrenheit to increase contact between the adhesive material and the metal powder after forming the powder mixture.

2. The method of claim 1 wherein:

forming the powder mixture includes forming the powder mixture to include fluoropolymer powder; and

shearing the binder powder includes shearing the binder powder to cause the adhesive material to bind together the metal powder and the fluoropolymer powder.

3. The method of claim 1 , further comprising forcing the powder mixture through a die to form an extrudate.

4. The method of claim 3 wherein shearing the binder powder includes shearing and heating the binder powder at the die.

5. The method of claim 1 wherein the anticaking material is a fluoropolymer.

6. The method of claim 5 wherein:

forming the powder mixture includes forming the powder mixture to include polytetrafluoroethylene powder; and

the anticaking material is polytetrafluoroethylene.

7. The method of claim 6 wherein the adhesive material is a copolymer including vinylidene fluoride and hexafluoropropylene monomers.

8. The method of claim 1 wherein the shearing comprises shearing the binder powder with heat over approximately 150 degrees Fahrenheit.

9. The method of claim 1 wherein the shearing comprises shearing the binder powder with heat over approximately 120 degrees Fahrenheit and less than approximately 400 degrees Fahrenheit.

10. A method for making a pyrotechnic composition, the method comprising:

flowing metal powder toward an extruder;

flowing fluoropolymer powder toward the extruder;

flowing binder powder toward the extruder, wherein the binder powder includes adhesive material and anticaking material disposed around the adhesive material; and

extruding a mixture of the metal powder, the fluoropolymer powder, and the binder powder to form an extrudate in which the adhesive material binds together the metal powder and the fluoropolymer powder.

11. The method of claim 10 wherein extruding the mixture shears the binder powder to increase contact between the adhesive material and the metal powder.

12. The method of claim 10 wherein:

the binder powder includes the anticaking material in a coating on the adhesive material; and

the coating is disrupted in the extrudate.

13. The method of claim 10 wherein:

the binder powder includes the anticaking material covering the adhesive material; and

extruding the mixture includes shearing the binder powder to uncover the adhesive material.

14. The method of claim 10 wherein:

the binder powder includes the anticaking material covering the adhesive material; and

the method further comprises shearing the binder powder to uncover the adhesive material after flowing the binder powder and before extruding the mixture.

15. The method of claim 10 wherein:

the metal powder is magnesium powder; and

the fluoropolymer powder is polytetrafluoroethylene powder.

16. The method of claim 10 wherein:

flowing the metal powder and the fluoropolymer powder includes flowing the metal powder and the fluoropolymer powder in separate respective feed streams to one or more inlets of the extruder; and

the method further comprises forming the mixture within the extruder at or downstream from the one or more inlets.

17. The method of claim 10 wherein:

flowing the metal powder includes flowing the metal powder along a first conveyance extending from a source of the metal powder toward the extruder;

flowing the fluoropolymer powder includes flowing the fluoropolymer powder along a second conveyance extending from a source of the fluoropolymer powder toward the extruder;

flowing the binder powder includes flowing the binder powder along a third conveyance extending from a source of the binder powder toward the extruder; and

the method further comprises interspersing the metal powder, the fluoropolymer powder, and the binder powder at a mixer downstream from the first, second, and third conveyances and upstream from the extruder.

18. The method of claim 17 wherein the mixer is a baffled funnel.

19. The method of claim 10 , further comprising forming the mixture, wherein the mixture includes no more than a trace concentration of solvent at any time between forming the mixture and extruding the mixture.

20. The method of claim 19 wherein the mixture includes no solvent at any time between forming the mixture and extruding the mixture.

21. The method of claim 10 wherein the anticaking material is a fluoropolymer.

22. The method of claim 21 wherein the anticaking material has a weight that is less than approximately 20% of the weight of the binder powder.

23. The method of claim 21 wherein:

the fluoropolymer powder is polytetrafluoroethylene powder; and

the anticaking material is polytetrafluoroethylene.

24. The method of claim 23 wherein the adhesive material is a copolymer including vinylidene fluoride and hexafluoropropylene monomers.