Solid rocket fuel composition containing metal hydride with butyl rubber and method of making same

Claim 1

A SOLID FUEL COMPOSITION SUITABLE FOR USE WITH A LIQUID OXIDIZER IN A HYBRID ROCKET MOTOR, WHICH COMPRISES A SOLIDLY COMPACTED AND HEAT-CURED GRAIN HAVING GOOD DIMENSIONAL STABILITY AND STRENGHT ADEQUATE TO RESIST THE STRESSES OF ROCKET MOTOR COMBUSION, SAID GRAIN CONSISTING OF ABOUT 90 PERCENT BY WEIGHT OF LITHIUM HYDRIDE AND ABOUT 10 PERCENT BY WEIGHT OF BUTYL RUBBER.

Claim 3

The method of preparing a solid fuel grain consisting essentially of 90 to 95 percent by weight of hydride of metal selected from the group consisting of lithium, sodium, potassium, aluminum, magnesium, and alloys thereof, and from 5 to 10 percent of synthetic rubber selected from the group consisting of butyl rubber and polyisobutylene rubber, which comprises: dissolving the solid synthetic rubber in moisture-free hydrocarbon solvent selected from the group consisting of hexane, cyclohexane and petroleum ether, in any proportions up to 35 percent by weight of rubber and 65 percent of solvent; introducing a small quantity of hydride into the rubber/solvent solution and allowing the same to react with any residual moisture while purging the surface with nitrogen; adding the remainder of the hydride to the rubber/solvent solution and thoroughly mixing the ingredients under vacuum to evaporate the solvent therefrom; loading the resultant crumb into a die; and pressing the crumb into a solidly compacted, coherent grain.

Claim 4

The method of preparing a solid fuel grain consisting essentially of 90 to 95 percent by weight of hydride of metal selected from the group consisting of lithium, sodium, potassium, aluminum, magnesium, and alloys thereof, and from 5 to 10 percent of synthetic rubber selected from the group consisting of butyl rubber and polyisobutylene rubber, which comprises: dissolving the solid synthetic rubber in moisture-free hydrocarbon solvent selected from the group consisting of hexane, cyclohexane and petroleum ether, in any proportions up to 35 percent by weight of rubber and 65 percent of solvent; introducing a small quantity of hydride into the rubber/solvent solution and allowing the same to react with any residual moisture while purging the surface with nitrogen; adding the remainder of the hydride to the rubber/solvent solution and thoroughly mixing the ingredients under vacuum to evaporate the solvent therefrom; loading the resultant crumb into a die; and pressing the crumb into a solidly compacted, coherent grain.

Claim 5

The method of preparing a solid fuel grain consisting essentially of about 90 percent by weight of lithium hydride and about 10 percent of cured butyl rubber, which comprises: dissolving solid butyl rubber containing some unsaturation capable of cross-linking with sulfur in dried hexane; introducing a small quantity, of the order of 10 grams per pound of rubber, of lithium hydride into the butyl rubber/hexane solution and allowing the same to react to completion with any residual moisture while purging the surface with nitrogen; adding the remainder of the lithium hydride to the solution; adding curatives including sulfur for cross-linking with the unsaturation of the butyl rubber; thoroughly mixing the ingredients under vacuum so as to remove substantially all of the hexane by evaporation; loading the resulting crumb into a die and pressing the same into a solidly compacted, coherent grain; and curing the said grain at an elevated temperature.

Claim 6

The method of preparing a solid fuel grain consisting essentially of about 90 percent by weight of lithium hydride and about 10 percent of cured butyl rubber, which comprises: dissolving solid butyl rubber containing some unsaturation capable of cross-linking with sulfur in dried hexane; introducing a small quantity, of the order of 10 grams per pound of rubber, of lithium hydride into the butyl rubber/hexane solution and allowing the same to react to completion with any residual moisture while purging the surface with nitrogen; adding the remainder of the lithium hydride to the solution; adding curatives including sulfur for cross-linking with the unsaturation of the butyl rubber; thoroughly mixing the ingredients under vacuum so as to remove substantially all of the hexane by evaporation; loading the resulting crumb into a die and pressing the same into a solidly compacted, coherent grain; and curing the said grain at an elevated temperature.