Patent GB-984960-A (GB)
Title: Solid propellant compositions
Inventor: KLAGER KARL
IPC: C06B45/12
Filed: 1960-08-02
Abstract: A solid propellent composition comprises a cured intimate mixture of a solid, inorganic oxidizing salt and a cross-linked resin binder which is the reaction product of a compound having not less than two hydroxy or thiol groups and a compound, e.g. a diisocyanate or diisothiocyanate, capable of undergoing a urethane-type reaction with the first compound. Preferably the oxidizing salt comprises about 45 to 95% by weight of the whole composition. The hydroxy or thiol compound is exemplified by many suitable alkane diols, alkene diols, cycloalkylene diols, aromatic diols, aliphatic-aromatic diols, diols containing hetero atoms, and corresponding dithiol compounds; polyesters obtained by reacting a dihydric alcohol with a dicarboxylic acid are also suitable and may be used together with an olefine, e.g. styrene or vinyl acetate; polyethers and polysulphides are also referred to. The isocyanate component may be an alkane, alkene, alkylidene, cycloalkylene, cycloalkylidene, aromatic, aliphatic-aromatic, or hetero atom-containing diisocyanate, or a corresponding diisothiocyanate; many of these compounds are listed. A slight excess of the isocyanate over the other reactants is preferable. A cross-linking agent may be included, in the form of an organic compound having three or more groups polymerizable with hydroxy or isocyanate groups; examples given include polyhydroxy and polyisocyanate compounds, polymeric compounds, cellulose and its derivatives, and proteins. Oxidizing salts which may be used are the chromates, dichromates, permanganates, nitrates, chlorates, and perchlorates of alkali or alkaline earth metals, or of ammonia, hydrazine, or guanidine.  Other ingredients which may be included are solvents, plasticizers, polymerization catalysts, burning rate modifiers, antioxidants, wetting agents, and anti-foaming agents. The ingredients may be added in various orders, mixed under vacuum, cast or extruded, and then cured at 70 DEG  to 180 DEG  F.; the propellent may be cast directly into a rocket chamber lined with a coating of inert resin, and provided with an igniter as described in Specification 892,881.  In examples, the following ingredients are used: as oxidizing salts, ammonium perchlorate, ammonium nitrate, sodium nitrate, potassium nitrate, and potassium chlorate; as resin components, polypropylene glycol, decamethylene glycol, 2,4-tolylene diisocyanate, and p,p1-diphenyl-methane diisocyanate; as cross-linking agents, glycerol monoricinoleate, nitro-isobutyl glycerol, the compound of formula <FORM:0984960/C1/1> tris - (hydroxymethyl)nitromethane, 2,4,6-tolylene triisocyanate, 1,2,6 - hexanetriol, N,N,N1,N1 - tetrakis - (2 -hydroxypropyl)-ethylenediamine, and monoethanol - trispropanol - ethylenediamine; as plasticizers, di-2-ethylhexylazelate and isodecyl pelargonate; as polymerization catalyst, ferric acetylacetonate and vanadyl acetylacetonate; as wetting agents, lecithin and a mixture of sorbitan monooleate and polyoxyethylene esters of mixed fatty and resin acids; as burning rate modifiers, copper chromite and carbon black; and as an anti-foaming agent, a silicone oil product.