초록 ▼

The present invention relates to the field of compound pyrotechnic products. The invention relates to a three-step, solvent-free process for the manufacture of compound pyrotechnic products containing a thermosetting binder obtained by reaction of a polyhydroxylated prepolymer with a diisocyanate, w

The present invention relates to the field of compound pyrotechnic products. The invention relates to a three-step, solvent-free process for the manufacture of compound pyrotechnic products containing a thermosetting binder obtained by reaction of a polyhydroxylated prepolymer with a diisocyanate, which process is characterized in that: in a first step the said prepolymer is mixed with an energetic charge and with a quantity of diisocyanate representing 50 to 90% of the required stoichiometric quantity, in a second step the remainder required to attain the said stoichiometric quantity is added and, after mixing, the pasty mixture thus obtained is extruded, in a third step the crosslinking of the thermosetting binder is completed hot. The invention makes it possible to obtain industrially, by extrusion, small-diameter pyrotechnic products containing a thermosetting binder without restriction on the “pot life”period. The invention is particularly suitable for the production of compound propellent powders for arms.

대표청구항 ▼

Process for the manufacture of compound pyrotechnic products consisting essentially of, a polyurethane binder obtained by the reaction of a polyhydroxylated prepolymer with a diisocyanate and at least one inorganic or organic energetic charge, wherein said polyhydroxylated prepolymer has a weight av

Process for the manufacture of compound pyrotechnic products consisting essentially of, a polyurethane binder obtained by the reaction of a polyhydroxylated prepolymer with a diisocyanate and at least one inorganic or organic energetic charge, wherein said polyhydroxylated prepolymer has a weight average molecular mass between 2,000 and 5,000 and an average hydroxyl OH group functionality greater than 2 and less than 3 and said process being comprised of the steps of (1) mixing said polyhydroxylated prepolymer with said energetic charge and with a quantity of diisocyanate which is between 50% and 90% by weight of the stoichiometric quantity required for complete polymerization of all the hydroxyl OH groups of said prepolymer, such that the condensation reaction of the isocyanate NCO groups with the hydroxyl OH groups produces a partially polymerized paste; (2) mixing said partially polymerized paste with the remainder of the diisocyanate required to attain the said stoichiometric quantity required for complete polymerization, and extruding the resultant paste mixture; and (3) hot curing said pasty mixture so as to complete the condensation reaction of the isocyanate NCO groups added during the second step with the hydroxyl groups of said prepolymer which are still free.