Processing procedure for isocyanate cured propellants containing some bismuth compounds

Abstract

A processing procedure for incorporating bismuth compounds into isocyanate cured hydroxy terminated binder propellants has been discovered. When added to the propellant formulation in ballistic modifier amounts (≧0.25%), bismuth salicylate and bismuth β-resorcylate significantly reduce the potlife to less than 1-hour. It was discovered that to maximize propellant potlife the temperature of the mixture at the time of the addition is critically important. The potlife of propellants containing bismuth compounds can be increased to greater than 15 hours at 70° F., when the temperature of the mixture at the addition step for bismuth, is lowered from the normal addition temperature of 150° F., to 60° F. Depending on the formulation and solids loading, the viscosity of the propellant at 60° F. is not greatly affected.

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